Appendectomy versus antibiotic treatment for acute appendicitis.

BACKGROUND: Acute appendicitis is one of the most common emergency general surgical conditions worldwide. Uncomplicated/simple appendicitis can be treated with appendectomy or antibiotics. Some studies have suggested possible benefits with antibiotics with reduced complications, length of hospital stay, and the number of days off work. However, surgery may improve success of treatment as antibiotic treatment is associated with recurrence and future need for surgery. OBJECTIVES: To assess the effects of antibiotic treatment for uncomplicated/simple acute appendicitis compared with appendectomy for resolution of symptoms and complications. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, and two trial registers (World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov) on 19 July 2022. We also searched for unpublished studies in conference proceedings together with reference checking and citation search. There were no restrictions on date, publication status, or language of publication. SELECTION CRITERIA: We included parallel-group randomised controlled trials (RCTs) only. We included studies where most participants were adults with uncomplicated/simple appendicitis. Interventions included antibiotics (by any route) compared with appendectomy (open or laparoscopic). DATA COLLECTION AND ANALYSIS: We used standard methodology expected by Cochrane. We used GRADE to assess the certainty of evidence for each outcome. Primary outcomes included mortality and success of treatment, and secondary outcomes included number of participants requiring appendectomy in the antibiotic group, complications, pain, length of hospital stay, sick leave, malignancy in the antibiotic group, negative appendectomy rate, and quality of life. Success of treatment definitions were heterogeneous although mainly based on resolution of symptoms rather than incorporation of long-term recurrence or need for surgery in the antibiotic group. MAIN RESULTS: We included 13 studies in the review covering 1675 participants randomised to antibiotics and 1683 participants randomised to appendectomy. One study was unpublished. All were conducted in secondary care and two studies received pharmaceutical funding. All studies used broad-spectrum antibiotic regimens expected to cover gastrointestinal bacteria. Most studies used predominantly laparoscopic surgery, but some included mainly open procedures. Six studies included adults and children. Almost all studies aimed to exclude participants with complicated appendicitis prior to randomisation, although one study included 12% with perforation. The diagnostic technique was clinical assessment and imaging in most studies. Only one study limited inclusion by sex (male only). Follow-up ranged from hospital admission only to seven years. Certainty of evidence was mainly affected by risk of bias (due to lack of blinding and loss to follow-up) and imprecision. Primary outcomes It is uncertain whether there was any difference in mortality due to the very low-certainty evidence (Peto odds ratio (OR) 0.51, 95% confidence interval (CI) 0.05 to 4.95; 1 study, 492 participants). There may be 76 more people per 1000 having unsuccessful treatment in the antibiotic group compared with surgery, which did not reach our predefined level for clinical significance (risk ratio (RR) 0.91, 95% CI 0.87 to 0.96; I2 = 69%; 7 studies, 2471 participants; low-certainty evidence). Secondary outcomes At one year, 30.7% (95% CI 24.0 to 37.8; I2 = 80%; 9 studies, 1396 participants) of participants in the antibiotic group required appendectomy or, alternatively, more than two-thirds of antibiotic-treated participants avoided surgery in the first year, but the evidence is very uncertain. Regarding complications, it is uncertain whether there is any difference in episodes of Clostridium difficile diarrhoea due to very low-certainty evidence (Peto OR 0.97, 95% CI 0.24 to 3.89; 1 study, 1332 participants). There may be a clinically significant reduction in wound infections with antibiotics (RR 0.25, 95% CI 0.09 to 0.68; I2 = 16%; 9 studies, 2606 participants; low-certainty evidence). It is uncertain whether antibiotics affect the incidence of intra-abdominal abscess or collection (RR 1.58, 95% CI 0.61 to 4.07; I2 = 19%; 6 studies, 1831 participants), or reoperation (Peto OR 0.13, 95% CI 0.01 to 2.16; 1 study, 492 participants) due to very low-certainty evidence, mainly due to rare events causing imprecision and risk of bias. It is uncertain if antibiotics prolonged length of hospital stay by half a day due to the very low-certainty evidence (MD 0.54, 95% CI 0.06 to 1.01; I2 = 97%; 11 studies, 3192 participants). The incidence of malignancy was 0.3% (95% CI 0 to 1.5; 5 studies, 403 participants) in the antibiotic group although follow-up was variable. Antibiotics probably increased the number of negative appendectomies at surgery (RR 3.16, 95% CI 1.54 to 6.49; I2 = 17%; 5 studies, 707 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS: Antibiotics may be associated with higher rates of unsuccessful treatment for 76 per 1000 people, although differences may not be clinically significant. It is uncertain if antibiotics increase length of hospital stay by half a day. Antibiotics may reduce wound infections. A third of the participants initially treated with antibiotics required subsequent appendectomy or two-thirds avoided surgery within one year, but the evidence is very uncertain. There were too few data from the included studies to comment on major complications.

Non-opioid analgesics for the prevention of chronic postsurgical pain: a systematic review and network meta-analysis.

BACKGROUND: Chronic postsurgical pain is common after surgery. Identification of non-opioid analgesics with potential for preventing chronic postsurgical pain is important, although trials are often underpowered. Network meta-analysis offers an opportunity to improve power and to identify the most promising therapy for clinical use and future studies. METHODS: We conducted a PRISMA-NMA-compliant systematic review and network meta-analysis of randomised controlled trials of non-opioid analgesics for chronic postsurgical pain. Outcomes included incidence and severity of chronic postsurgical pain, serious adverse events, and chronic opioid use. RESULTS: We included 132 randomised controlled trials with 23 902 participants. In order of efficacy, i.v. lidocaine (odds ratio [OR] 0.32; 95% credible interval [CrI] 0.17-0.58), ketamine (OR 0.64; 95% CrI 0.44-0.92), gabapentinoids (OR 0.67; 95% CrI 0.47-0.92), and possibly dexmedetomidine (OR 0.36; 95% CrI 0.12-1.00) reduced the incidence of chronic postsurgical pain at ≤6 months. There was little available evidence for chronic postsurgical pain at >6 months, combinations agents, chronic opioid use, and serious adverse events. Variable baseline risk was identified as a potential violation to the network meta-analysis transitivity assumption, so results are reported from a fixed value of this, with analgesics more effective at higher baseline risk. The confidence in these findings was low because of problems with risk of bias and imprecision. CONCLUSIONS: Lidocaine (most effective), ketamine, and gabapentinoids could be effective in reducing chronic postsurgical pain ≤6 months although confidence is low. Moreover, variable baseline risk might violate transitivity in network meta-analysis of analgesics; this recommends use of our methods in future network meta-analyses. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42021269642.

The role of resistance exercise training for improving cardiorespiratory fitness in healthy older adults: a systematic review and meta-analysis.

BACKGROUND: Declines in cardiorespiratory fitness (CRF) and muscle mass are both associated with advancing age and each of these declines is associated with worse health outcomes. Resistance exercise training (RET) has previously been shown to improve muscle mass and function in the older population. If RET is also able to improve CRF, as it has been shown to do in younger populations, it has the potential to improve multiple health outcomes in the expanding older population. METHODS: This systematic review aimed to identify the role of RET for improving CRF in healthy older adults. A search across CINAHL, MEDLINE, EMBASE and EMCARE databases was conducted with meta-analysis performed on eligible papers to identify improvements in established CRF parameters (VO2 peak, aerobic threshold (AT), 6-minute walking distance test (6MWT) following RET intervention. Main eligibility criteria included older adults (aged over 60), healthy cohorts (disease-specific cohorts were excluded) and RET intervention. RESULTS: Thirty-seven eligible studies were identified. Meta-analysis revealed a significant improvement in VO2 peak (MD 1.89 ml/kg/min; 95% confidence interval (CI) 1.21-2.57 ml/kg/min), AT (MD 1.27 ml/kg/min; 95% CI 0.44-2.09 ml/kg/min) and 6MWT (MD 30.89; 95% CI 26.7-35.08) in RET interventions less than 24 weeks. There was no difference in VO2 peak or 6MWT in interventions longer than 24 weeks. DISCUSSION: This systematic review adds to a growing body of evidence supporting the implementation of RET in the older population for improving whole-body health, particularly in time-limited timeframes.

Post-operative electrical muscle stimulation attenuates loss of muscle mass and function following major abdominal surgery in older adults: a split body randomised control trial.

INTRODUCTION: Significant losses of muscle mass and function occur after major abdominal surgery. Neuromuscular electrical stimulation (NMES) has been shown to reduce muscle atrophy in some patient groups, but evidence in post-operative patients is limited. This study assesses the efficacy of NMES for attenuating muscle atrophy and functional declines following major abdominal surgery in older adults. METHODS: Fifteen patients undergoing open colorectal resection completed a split body randomised control trial. Patients' lower limbs were randomised to control (CON) or NMES (STIM). The STIM limb underwent 15 minutes of quadriceps NMES twice daily on post-operative days (PODs) 1-4. Ultrasound measurements of Vastus Lateralis cross-sectional area (CSA) and muscle thickness (MT) were made preoperatively and on POD 5, as was dynamometry to determine knee extensor strength (KES). Change in CSA was the primary outcome. All outcomes were statistically analysed using linear mixed models. RESULTS: NMES significantly reduced the loss of CSA (-2.52 versus -9.16%, P < 0.001), MT (-2.76 versus -8.145, P = 0.001) and KES (-10.35 versus -19.69%, P = 0.03) compared to CON. No adverse events occurred, and patients reported that NMES caused minimal or no discomfort and felt that ~90-minutes of NMES daily would be tolerable. DISCUSSION: NMES reduces losses of muscle mass and function following major abdominal surgery, and as such, may be the promising tool for post-operative recovery. This is important in preventing long-term post-operative dependency, especially in the increasingly frail older patients undergoing major abdominal surgery. Further studies should establish the efficacy of bilateral NMES for improving patient-centred outcomes.

Dressings and topical agents for the management of open wounds after surgical treatment for sacrococcygeal pilonidal sinus.

BACKGROUND: Sacrococcygeal pilonidal sinus disease is a common debilitating condition that predominantly affects young adults, with a profound impact on their activities of daily living. The condition is treated surgically, and in some cases the wound in the natal cleft is left open to heal by itself. Many dressings and topical agents are available to aid healing of these wounds. OBJECTIVES: To assess the effects of dressings and topical agents for the management of open wounds following surgical treatment for sacrococcygeal pilonidal sinus in any care setting. SEARCH METHODS: In March 2021, we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and we scanned reference lists of included studies, reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. SELECTION CRITERIA: We included parallel-group randomised controlled trials (RCTs) only. We included studies with participants who had undergone any type of sacrococcygeal pilonidal sinus disease surgery and were left with an open wound. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence for each outcome. MAIN RESULTS: We included 11 RCTs comprising 932 participants. Two studies compared topical negative pressure wound therapy (TNPWT) with conventional open wound healing, two studies compared platelet-rich plasma with sterile absorbent gauze, and the other seven studies compared various dressings and topical agents. All studies were at high risk of bias in at least one domain, whilst one study was judged to be at low risk of bias in all but one domain. All studies were conducted in secondary care. Mean participant ages were between 20 and 30 years, and nearly 80% of participants were male. No studies provided data on quality of life, cost-effectiveness, pain at first dressing change or proportion of wounds healed at 6 or 12 months, and very few adverse effects were recorded in any study. It is unclear whether TNPWT reduces time to wound healing compared with conventional open wound healing (comparison 1), as the certainty of evidence is very low. The two studies provided conflicting results, with one study showing benefit (mean difference (MD) -24.01 days, 95% confidence interval (CI) -35.65 to -12.37; 19 participants), whilst the other reported no difference. It is also unclear whether TNPWT has any effect on the proportion of wounds healed by 30 days (risk ratio (RR) 3.60, 95% CI 0.49 to 26.54; 19 participants, 1 study; very low-certainty evidence). Limited data were available for our secondary outcomes time to return to normal daily activities and recurrence rate; we do not know whether TNPWT has any effect on these outcomes. Lietofix cream may increase the proportion of wounds that heal by 30 days compared with an iodine dressing (comparison 4; RR 8.06, 95% CI 1.05 to 61.68; 205 participants, 1 study; low-certainty evidence). The study did not provide data on time to wound healing. We do not know whether hydrogel dressings reduce time to wound healing compared with wound cleaning with 10% povidone iodine (comparison 5; MD -24.54 days, 95% CI -47.72 to -1.36; 31 participants, 1 study; very low-certainty evidence). The study did not provide data on the proportion of wounds healed. It is unclear whether hydrogel dressings have any effect on adverse effects as the certainty of the evidence is very low. Platelet-rich plasma may reduce time to wound healing compared with sterile absorbent gauze (comparison 6; MD -19.63 days, 95% CI -34.69 to -4.57; 210 participants, 2 studies; low-certainty evidence). No studies provided data on the proportion of wounds healed. Platelet-rich plasma may reduce time to return to normal daily activities (MD -15.49, 95% CI -28.95 to -2.02; 210 participants, 2 studies; low-certainty evidence). Zinc oxide mesh may make little or no difference to time to wound healing compared with placebo (comparison 2; median 54 days in the zinc oxide mesh group versus 62 days in the placebo mesh group; low-certainty evidence). We do not know whether zinc oxide mesh has an effect on the proportion of wounds healed by 30 days as the certainty of the evidence is very low (RR 2.35, 95% CI 0.49 to 11.23). It is unclear whether gentamicin-impregnated collagen sponge reduces time to wound healing compared with no dressing (comparison 7; MD -1.40 days, 95% CI -5.05 to 2.25; 50 participants, 1 study; very low-certainty evidence). The study did not provide data on the proportion of wounds healed. Dialkylcarbamoyl chloride (DACC)-coated dressings may make little or no difference to time to wound healing compared with alginate dressings (comparison 8; median 69 (95% CI 62 to 72) days in the DACC group versus 71 (95% CI 69 to 85) days in the alginate group; 1 study, 246 participants; low-certainty evidence). One study compared a polyurethane foam hydrophilic dressing with an alginate dressing (comparison 3) whilst another study compared a hydrocolloid dressing with an iodine dressing (comparison 9). It is unclear whether either intervention has any effect on time to wound healing as the certainty of evidence is very low. AUTHORS' CONCLUSIONS: At present, the evidence that any of the dressings or topical agents contained in this review have a benefit on time to wound healing, the proportion of wounds that heal at a specific time point or on any of the secondary outcomes of our review ranges from low certainty to very low certainty. There is low-certainty evidence on the benefit on wound healing of platelet-rich plasma from two studies and of Lietofix cream and hydrogel dressings from single studies. Further studies are required to investigate these interventions further.

Equipment-free, unsupervised high intensity interval training elicits significant improvements in the physiological resilience of older adults.

BACKGROUND: Reduced cardiorespiratory fitness (CRF) is an independent risk factor for dependency, cognitive impairment and premature mortality. High-intensity interval training (HIIT) is a proven time-efficient stimulus for improving both CRF and other facets of cardiometabolic health also known to decline with advancing age. However, the efficacy of equipment-free, unsupervised HIIT to improve the physiological resilience of older adults is not known. METHODS: Thirty independent, community-dwelling older adults (71(SD: 5) years) were randomised to 4 weeks (12 sessions) equipment-free, supervised (in the laboratory (L-HIIT)) or unsupervised (at home (H-HIIT)) HIIT, or a no-intervention control (CON). HIIT involved 5, 1-minute intervals of a bodyweight exercise each interspersed with 90-seconds recovery. CRF, exercise tolerance, blood pressure (BP), body composition, muscle architecture, circulating lipids and glucose tolerance were assessed at baseline and after the intervention period. RESULTS: When compared to the control group, both HIIT protocols improved the primary outcome of CRF ((via anaerobic threshold) mean difference, L-HIIT: +2.27, H-HIIT: +2.29, both p < 0.01) in addition to exercise tolerance, systolic BP, total cholesterol, non-HDL cholesterol and m. vastus lateralis pennation angle, to the same extent. There was no improvement in these parameters in CON. There was no change in diastolic BP, glucose tolerance, whole-body composition or HDL cholesterol in any of the groups. CONCLUSIONS: This is the first study to show that short-term, time-efficient, equipment-free, HIIT is able to elicit improvements in the CRF of older adults irrespective of supervision status. Unsupervised HIIT may offer a novel approach to improve the physiological resilience of older adults, combating age-associated physiological decline, the rise of inactivity and the additional challenges currently posed by the COVID-19 pandemic. TRIAL REGISTRATION: This study was registered at clinicaltrials.gov and coded: NCT03473990 .

Methodologies for systematic reviews with meta-analysis of randomised clinical trials in pain, anaesthesia, and perioperative medicine.

Systematic reviews and meta-analyses (SRMAs) are increasing in popularity, but should they be used to inform clinical decision-making in anaesthesia? We present evidence that the certainty of evidence from SRMAs in anaesthesia (and in general) may be unacceptably low because of risks of bias exaggerating treatment effects, unexplained heterogeneity reducing certainty in estimates, random errors, and widespread prevalence of publication bias. We also present the latest methodological advances to help improve the certainty of evidence from SRMAs. The target audience includes both review authors and practising clinicians to help with SRMA appraisal. Issues discussed include minimising risks of bias from included trials, trial sequential analysis to reduce random error, updated methods for presenting effect estimates, and novel publication bias tests for commonly used outcome measures. These methods can help to reduce spurious conclusions on clinical significance, explain statistical heterogeneity, and reduce false positives when evaluating small-study effects. By reducing concerns in these domains of Grading of Recommendations, Assessment, Development and Evaluation, it should help improve the certainty of evidence from SRMAs used for decision-making in anaesthesia, pain, and perioperative medicine.

Pre-emptive and preventive NSAIDs for postoperative pain in adults undergoing all types of surgery.

BACKGROUND: Postoperative pain is a common consequence of surgery and can have many negative perioperative effects. It has been suggested that the administration of analgesia before a painful stimulus may improve pain control. We defined pre-emptive nonsteroidal anti-inflammatories (NSAIDs) as those given before surgery but not continued afterwards and preventive NSAIDs as those given before surgery and continued afterwards. These were compared to a control group given the NSAIDs after surgery instead of before surgery. OBJECTIVES: To assess the efficacy of preventive and pre-emptive NSAIDs for reducing postoperative pain in adults undergoing all types of surgery. SEARCH METHODS: We searched the following electronic databases: CENTRAL, MEDLINE, Embase, AMED and CINAHL (up to June 2020). In addition, we searched for unpublished studies in three clinical trial databases, conference proceedings, grey literature databases, and reference lists of retrieved articles. We did not apply any restrictions on language or date of publication. SELECTION CRITERIA: We included parallel-group randomized controlled trials (RCTs) only. We included adult participants undergoing any type of surgery. We defined pre-emptive NSAIDs as those given before surgery but not continued afterwards and preventive NSAIDs as those given before surgery and continued afterwards. These were compared to a control group given the NSAIDs after surgery instead of before surgery. We included studies that gave the medication by any route but not given on the skin. DATA COLLECTION AND ANALYSIS: We used the standard methods expected by Cochrane, as well as a novel publication bias test developed by our research group. We used GRADE to assess the certainty of the evidence for each outcome. Outcomes included acute postoperative pain (minimal clinically important difference (MCID): 1.5 on a 0-10 scale), adverse events of NSAIDs, nausea and vomiting, 24-hour morphine consumption (MCID: 10 mg reduction), time to analgesic request (MCID: one hour), pruritus, sedation, patient satisfaction, chronic pain and time to first bowel movement (MCID: 12 hours). MAIN RESULTS: We included 71 RCTs. Seven studies are awaiting classification. We included 45 studies that evaluated pre-emptive NSAIDs and 26 studies that evaluated preventive NSAIDs. We considered only four studies to be at low risk of bias for most domains. The operations and NSAIDs used varied, although most studies were conducted in abdominal, orthopaedic and dental surgery. Most studies were conducted in secondary care and in low-risk participants. Common exclusions were participants on analgesic medications prior to surgery and those with chronic pain. Pre-emptive NSAIDs compared to post-incision NSAIDs For pre-emptive NSAIDs, there is probably a decrease in early acute postoperative pain (MD -0.69, 95% CI -0.97 to -0.41; studies = 36; participants = 2032; I2 = 96%; moderate-certainty evidence). None of the included studies that reported on acute postoperative pain reported adverse events as an outcome. There may be little or no difference between the groups in short-term (RR 1.00, 95% CI 0.34 to 2.94; studies = 2; participants = 100; I2 = 0%; low-certainty evidence) or long-term nausea and vomiting (RR 0.85, 95% CI 0.52 to 1.38; studies = 5; participants = 228; I2 = 29%; low-certainty evidence). There may be a reduction in late acute postoperative pain (MD -0.22, 95% CI -0.44 to 0.00; studies = 28; participants = 1645; I2 = 97%; low-certainty evidence). There may be a reduction in 24-hour morphine consumption with pre-emptive NSAIDs (MD -5.62 mg, 95% CI -9.00 mg to -2.24 mg; studies = 16; participants = 854; I2 = 99%; low-certainty evidence) and an increase in the time to analgesic request (MD 17.04 minutes, 95% CI 3.77 minutes to 30.31 minutes; studies = 18; participants = 975; I2 = 95%; low-certainty evidence). There may be little or no difference in opioid adverse events such as pruritus (RR 0.40, 95% CI 0.09 to 1.76; studies = 4; participants = 254; I2 = 0%; low-certainty evidence) or sedation (RR 0.51, 95% CI 0.16 to 1.68; studies = 4; participants = 281; I2 = 0%; low-certainty evidence), although the number of included studies for these outcomes was small. No study reported patient satisfaction, chronic pain or time to first bowel movement for pre-emptive NSAIDs. Preventive NSAIDs compared to post-incision NSAIDs For preventive NSAIDs, there may be little or no difference in early acute postoperative pain (MD -0.14, 95% CI -0.39 to 0.12; studies = 18; participants = 1140; I2 = 75%; low-certainty evidence). One study reported adverse events from NSAIDs (reoperation for bleeding) although the events were low which did not allow any meaningful conclusions to be drawn (RR 1.95; 95% CI 0.18 to 20.68). There may be little or no difference in rates of short-term (RR 1.26, 95% CI 0.49 to 3.30; studies = 1; participants = 76; low-certainty evidence) or long-term (RR 0.85, 95% CI 0.52 to 1.38; studies = 5; participants = 456; I2 = 29%; low-certainty evidence) nausea and vomiting. There may be a reduction in late acute postoperative pain (MD -0.33, 95% CI -0.59 to -0.07; studies = 21; participants = 1441; I2 = 81%; low-certainty evidence). There is probably a reduction in 24-hour morphine consumption (MD -1.93 mg, 95% CI -3.55 mg to -0.32 mg; studies = 16; participants = 1323; I2 = 49%; moderate-certainty evidence). It is uncertain if there is any difference in time to analgesic request (MD 8.51 minutes, 95% CI -31.24 minutes to 48.27 minutes; studies = 8; participants = 410; I2 = 98%; very low-certainty evidence). As with pre-emptive NSAIDs, there may be little or no difference in other opioid adverse events such as pruritus (RR 0.56, 95% CI 0.09 to 3.35; studies = 3; participants = 211; I2 = 0%; low-certainty evidence) and sedation (RR 0.84, 95% CI 0.44 to 1.63; studies = 5; participants = 497; I2 = 0%; low-certainty evidence). There is probably little or no difference in patient satisfaction (MD -0.42; 95% CI -1.09 to 0.25; studies = 1; participants = 72; moderate-certainty evidence). No study reported on chronic pain. There is probably little or no difference in time to first bowel movement (MD 0.00; 95% CI -15.99 to 15.99; studies = 1; participants = 76; moderate-certainty evidence). AUTHORS' CONCLUSIONS: There was some evidence that pre-emptive and preventive NSAIDs reduce both pain and morphine consumption, although this was not universal for all pain and morphine consumption outcomes. Any differences found were not clinically significant, although we cannot exclude this in more painful operations. Moreover, without any evidence of reductions in opioid adverse effects, the clinical significance of these results is questionable although few studies reported these outcomes. Only one study reported clinically significant adverse events from NSAIDs administered before surgery and, therefore, we have very few data to assess the safety of either pre-emptive or preventive NSAIDs. Therefore, future research should aim to adhere to the highest methodology and be adequately powered to assess serious adverse events of NSAIDs and reductions in opioid adverse events.

Contrast-enhanced ultrasound assessed renal microvascular perfusion may predict postoperative renal complications following colorectal surgery.

Colorectal surgery is associated with an above-average mortality rate of approximately 15%. During surgery, maintenance of vital organ perfusion is essential in order to reduce postoperative mortality and morbidity, with renal perfusion of particular importance. Oesophageal Doppler monitors (ODM) are commonly used to try and provide accurate measures of fluid depletion during surgery; however, it is unclear to what extent they reflect organ perfusion. In addition, it is not known whether macro- and/ or microvascular perfusion indices are associated with renal complications following colorectal surgery. Thirty-two participants scheduled for colorectal surgery had three measures of macro- and microvascular renal blood flow via contrast enhanced ultrasound (CEUS), and simultaneous measures of cardiac output indices via ODM: (i) pre-operatively; (ii) intra-operatively at the mid-point of operation, and (iii) after the conclusion of surgery. The Postoperative Morbidity Survey (POMS) was used to assess postoperative complications. Intra-operatively, there was a significant correlation between renal microvascular flow (RT) and renal macrovascular flow (TTI) (ρ = 0.52; p = 0.003). Intra-operative TTI, but not RT, was associated with cardiac index (ρ = -0.50; p=0.0003). Intra-operative RT predicted increases in renal complications (OR 1.46; 95% CI 1.03-2.09) with good discrimination (C-statistic, 0.85). Complications were not predicted by TTI or ODM-derived indices. There was no relationship between RT and TTI before or after surgery. ODM measures of haemodynamic status do not correlate with renal microvascular blood flow, and as such are likely not suitable to determine vital organ perfusion. Only CEUS-derived measures of microvascular perfusion were predictive of postoperative renal complications.

Prophylactic antibiotics for penetrating abdominal trauma: duration of use and antibiotic choice.

BACKGROUND: Penetrating abdominal trauma (PAT) is a common type of trauma leading to admission to hospital, which often progresses to septic complications. Antibiotics are commonly administered as prophylaxis prior to laparotomy for PAT. However, an earlier Cochrane Review intending to compare antibiotics with placebo identified no relevant randomised controlled trials (RCTs). Despite this, many RCTs have been carried out that compare different agents and durations of antibiotic therapy. To date, no systematic review of these trials has been performed. OBJECTIVES: To assess the effects of antibiotics in penetrating abdominal trauma, with respect to the type of agent administered and the duration of therapy. SEARCH METHODS: We searched the following electronic databases for relevant randomised controlled trials, from database inception to 23 July 2019; Cochrane Injuries Group's Specialised Register, CENTRAL, MEDLINE Ovid, MEDLINE Ovid In-Process & Other Non-Indexed Citations, MEDLINE Ovid Daily and Ovid OLDMEDLINE, Embase Classic + Embase Ovid, ISI Web of Science (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), and two clinical trials registers. We also searched reference lists from included studies. We applied no restrictions on language or date of publication. SELECTION CRITERIA: We included RCTs only. We included studies involving participants of all ages, which were conducted in secondary care hospitals only. We included studies of participants who had an isolated penetrating abdominal wound that breached the peritoneum, who were not already taking antibiotics. DATA COLLECTION AND ANALYSIS: Two study authors independently extracted data and assessed risk of bias. We used standard Cochrane methods. We aggregated study results using a random-effects model. We also conducted trial sequential analysis (TSA) to help reduce type I and II errors in our analyses. MAIN RESULTS: We included 29 RCTs, involving a total of 4458 participants. We deemed 23 trials to be at high risk of bias in at least one domain. We are uncertain of the effect of a long course of antibiotic prophylaxis (> 24 hours) compared to a short course (≤ 24 hours) on abdominal surgical site infection (RR 1.00, 95% CI 0.81 to 1.23; I² = 0%; 7 studies, 1261 participants; very low-quality evidence), mortality (Peto OR 1.67, 95% CI 0.73 to 3.82; I² = 8%; 7 studies, 1261 participants; very low-quality evidence), or intra-abdominal infection (RR 1.23, 95% CI 0.84 to 1.80; I² = 0%; 6 studies, 111 participants; very-low quality evidence). Based on very low-quality evidence from fifteen studies, involving 2020 participants, which compared different drug regimens with activity against three classes of gastrointestinal flora (gram positive, gram negative, anaerobic), we are uncertain whether there is a benefit of one regimen over another. TSA showed the majority of comparisons did not cross the alpha adjusted boundary for benefit or harm, or reached the required information size, indicating that further studies are required for these analyses. However, in the three analyses which crossed the boundary for futility, further studies are unlikely to show benefit or harm. AUTHORS' CONCLUSIONS: Very low-quality evidence means that we are uncertain about the effect of either the duration of antibiotic prophylaxis, or the superiority of one drug regimen over another for penetrating abdominal trauma on abdominal surgical site infection rates, mortality, or intra-abdominal infections. Future RCTs should be adequately powered, test currently used antibiotics, known to be effective against gut flora, use methodology to minimise the risk of bias, and adequately report the level of peritoneal contamination encountered at laparotomy.

Mirtazapine for Postoperative Nausea and Vomiting: Systematic Review, Meta-analysis, and Trial Sequential Analysis.

PURPOSE: Patients rank postoperative nausea and vomiting (PONV) as the most undesirable outcome of anesthesia. Mirtazapine is hypothesized to be effective in PONV prophylaxis via 5HT3 receptor antagonism. DESIGN: Systematic review and meta-analysis. METHODS: We identified seven randomized controlled trials by systematically searching electronic databases that compare the efficacy of mirtazapine versus placebo or ondansetron in reducing PONV. FINDINGS: Mirtazapine reduced PONV overall versus placebo in three studies (risk ratio [RR] = 0.44; 95% confidence interval [CI] 0.32 to 0.62) both on conventional meta-analysis and trial sequential analysis. One study comparing mirtazapine with ondansetron found similar rates of PONV (RR = 0.96; 95% CI 0.48 to 1.94). Mirtazapine reduced preoperative anxiety versus placebo or ondansetron (standardized mean difference -1.4; 95% CI -2.56 to -0.23) but increased sedation (RR = 22.47; 95% CI 5.61 to 89.93). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) quality of evidence was moderate to low. CONCLUSIONS: This meta-analysis suggests that mirtazapine reduces PONV overall versus placebo. We found evidence of reduction in preoperative anxiety, although mirtazapine increased the risk of sedation.

Baseline Morphine Consumption May Explain Between-Study Heterogeneity in Meta-analyses of Adjuvant Analgesics and Improve Precision and Accuracy of Effect Estimates.

BACKGROUND: Statistical heterogeneity can increase the uncertainty of results and reduce the quality of evidence derived from systematic reviews. At present, it is uncertain what the major factors are that account for heterogeneity in meta-analyses of analgesic adjuncts. Therefore, the aim of this review was to identify whether various covariates could explain statistical heterogeneity and use this to improve accuracy when reporting the efficacy of analgesics. METHODS: We searched for reviews using MEDLINE, EMBASE, CINAHL, AMED, and the Cochrane Database of Systematic Reviews. First, we identified the existence of considerable statistical heterogeneity (I > 75%). Second, we conducted meta-regression analysis for the outcome of 24-hour morphine consumption using baseline risk (control group morphine consumption) and other clinical and methodological covariates. Finally, we constructed a league table of adjuvant analgesics using a novel method of reporting effect estimates assuming a fixed consumption of 50 mg postoperative morphine. RESULTS: We included 344 randomized controlled trials with 28,130 participants. Ninety-one percent of analyses showed considerable statistical heterogeneity. Baseline risk was a significant cause of between-study heterogeneity for acetaminophen, nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors, tramadol, ketamine, α2-agonists, gabapentin, pregabalin, lidocaine, magnesium, and dexamethasone (R = 21%-100%; P < .05). There was some evidence that the methodological limitations of the trials explained some of the residual heterogeneity. Type of surgery was not independently associated with analgesic efficacy. Assuming a fixed baseline risk of 50 mg (in order of efficacy), gabapentin, acetaminophen, α2-agonists, nonsteroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors, pregabalin, tramadol, magnesium, and lidocaine demonstrated moderate clinically significant reductions (>10 mg). We could not exclude a moderate clinically significant effect with ketamine. Dexamethasone demonstrated a small clinical benefit (>5 mg). CONCLUSIONS: We empirically identified baseline morphine consumption as the major source of heterogeneity in meta-analyses of adjuvant analgesics across all surgical interventions. Controlling for baseline morphine consumption, clinicians can use audit data to estimate the morphine-reducing effect of adding any adjuvant for their local population, regardless which surgery they undergo. Moreover, we have utilized these findings to present a novel method of reporting and an amended method of graphically displaying effect estimates, which both reduces confounding from variable baseline risk in included trials and is able to adjust for other clinical and methodological confounding variables. We recommend use of these methods in clinical practice and future reviews of analgesics for postoperative pain.

Pre-emptive and preventive opioids for postoperative pain in adults undergoing all types of surgery.

BACKGROUND: Postoperative pain is a common consequence of surgery and can have deleterious effects. It has been suggested that the administration of opioid analgesia before a painful stimulus may improve pain control. This can be done in two ways. We defined 'preventive opioids' as opioids administered before incision and continued postoperatively, and 'pre-emptive opioids' as opioids given before incision but not continued postoperatively. Both pre-emptive and preventive analgesia involve the initiation of an analgesic agent prior to surgical incision with the aim of reducing intraoperative nociception and therefore postoperative pain. OBJECTIVES: To assess the efficacy of preventive and pre-emptive opioids for reducing postoperative pain in adults undergoing all types of surgery. SEARCH METHODS: We searched the following electronic databases: CENTRAL, MEDLINE, Embase, AMED, and CINAHL (up to 18 March 2018). In addition, we searched for unpublished studies in three clinical trial databases, conference proceedings, grey literature databases, and reference lists of retrieved articles. We did not apply any restrictions on language or date of publication. SELECTION CRITERIA: We included parallel-group randomized controlled trials (RCTs) only. We included participants aged over 15 years old undergoing any type of surgery. We defined postincision opioids as the same intervention administered after incision whether single dose (as comparator with pre-emptive analgesia) or continued postoperatively (as comparator with preventive analgesia) (control group). We considered studies that did and did not use a double-dummy placebo (e.g. intervention group received active drug before incision and placebo after incision; control group received placebo before incision and active drug after incision). DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by Cochrane. Our primary outcomes were: early acute postoperative pain (measured within six hours and reported on a 0-to-10 scale) and respiratory depression. Our secondary outcomes included: late acute postoperative pain (24 to 48 hours and reported on a 0-to-10 scale), 24-hour morphine consumption, and adverse events (intraoperative bradycardia and hypotension). We used GRADE to assess the quality of the evidence for each outcome. MAIN RESULTS: We included 20 RCTs, including one unpublished study with 1343 participants. Two studies were awaiting classification as the full text for these studies was not available. One study evaluated pre-emptive opioids, and 19 studies evaluated preventive opioids. We considered only one study to be at low risk of bias for most domains. The surgeries and opioids used varied, although roughly half of the included studies were conducted in abdominal hysterectomy, and around a quarter used morphine as the intervention. All studies were conducted in secondary care.Pre-emptive opioids compared to postincision opioidsFor pre-emptive opioids in dental surgery, there may be a reduction in early acute postoperative pain (mean difference (MD) -1.20, 95% confidence interval (CI) -1.75 to -0.65; 40 participants; 1 study; low-quality evidence). This study did not report on adverse events (respiratory depression, bradycardia, or hypotension). There may be a reduction in late acute postoperative pain (MD -2.10, 95% CI -2.57 to -1.63; 40 participants; 1 study; low-quality evidence). This study did not report 24-hour morphine consumption.Preventive opioids compared to postincision opioidsFor preventive opioids, there was probably no reduction in early acute postoperative pain (MD 0.11, 95% CI -0.32 to 0.53; 706 participants; 10 studies; I2 = 61%; moderate-quality evidence). There were no events of respiratory depression in four studies (433 participants). There was no important reduction in late acute postoperative pain (MD -0.06, 95% CI -0.13 to 0.01; 668 participants; 9 studies; I2 = 0%; moderate-quality evidence). There may be a small reduction in 24-hour morphine consumption (MD -4.91 mg, 95% CI -9.39 mg to -0.44 mg; 526 participants; 11 studies; I2 = 82%; very low-quality evidence). There may be similar rates of bradycardia (risk ratio (RR) 0.33, 95% CI 0.01 to 7.88; 112 participants; 2 studies; I2 = 0%; low-quality evidence) and hypotension (RR 1.08, 95% CI 0.25 to 4.73; 88 participants; 2 studies; I2 = 0%; low-quality evidence). AUTHORS' CONCLUSIONS: Due to the low quality of the evidence, we are uncertain whether pre-emptive opioids reduce postoperative pain. Based on the trials conducted thus far, there was no clear evidence that preventive opioids result in reductions in pain scores. It was unclear if there was a reduction in morphine consumption due to very low-quality of evidence. Too few studies reported adverse events to be able to draw any definitive conclusions. Once assessed, the two studies awaiting classification may alter the conclusions of the review.

Fibrin glue for pilonidal sinus disease.

BACKGROUND: Pilonidal sinus disease is a common condition that mainly affects young adults. This condition can cause significant pain and impairment of normal activities. No consensus currently exists on the optimum treatment for pilonidal sinus and current therapies have various advantages and disadvantages. Fibrin glue has emerged as a potential treatment as both monotherapy and an adjunct to surgery. OBJECTIVES: To assess the effects of fibrin glue alone or in combination with surgery compared with surgery alone in the treatment of pilonidal sinus disease. SEARCH METHODS: In December 2016 we searched: the Cochrane Wounds Specialised Register; CENTRAL; MEDLINE; Embase and CINAHL Plus. We also searched clinical trials registries and conference proceedings for ongoing and unpublished studies and scanned reference lists to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. SELECTION CRITERIA: We included randomised controlled trials (RCTs) only. We included studies involving participants of all ages and studies conducted in any setting. We considered studies involving people with both new and recurrent pilonidal sinus. We included studies which evaluated fibrin glue monotherapy or as an adjunct to surgery. DATA COLLECTION AND ANALYSIS: Two study authors independently extracted data and assessed risk of bias. We used standard methods expected by Cochrane. MAIN RESULTS: We included four RCTs with 253 participants, all were at risk of bias. One unpublished study evaluated fibrin glue monotherapy compared with Bascom's procedure, two studies evaluated fibrin glue as an adjunct to Limberg flap and one study evaluated fibrin glue as an adjunct to Karydakis flap.For fibrin glue monotherapy compared with Bascom's procedure, there were no data available for the primary outcomes of time to healing and adverse events. There was low-quality evidence of less pain on day one after the procedure with fibrin glue monotherapy compared with Bascom's procedure (mean difference (MD) -2.50, 95% confidence interval (CI) -4.03 to -0.97) (evidence downgraded twice for risk of performance and detection bias). Fibrin glue may reduce the time taken to return to normal activities compared with Bascom's procedure (mean time 42 days with surgery and 7 days with glue, MD -34.80 days, 95% CI -66.82 days to -2.78 days) (very low-quality evidence, downgraded as above and for imprecision).Fibrin glue as an adjunct to the Limberg flap may reduce the healing time from 22 to 8 days compared with the Limberg flap alone (MD -13.95 days, 95% CI -16.76 days to -11.14 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). It is uncertain whether use of fibrin glue affects the incidence of postoperative seroma (an adverse event) (risk ratio (RR) 0.27, 95% CI 0.05 to 1.61; very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). There was low-quality evidence that fibrin glue, as an adjunct to Limberg flap, may reduce postoperative pain (median 2 versus 4; P < 0.001) and time to return to normal activities (median 8 days versus 17 days; P < 0.001). The addition of fibrin glue to the Limberg flap may reduce the length of hospital stay (MD -1.69 days, 95% CI -2.08 days to -1.29 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for unexplained heterogeneity).A single RCT evaluating fibrin glue as an adjunct to the Karydakis flap did not report data for the primary outcome of time to healing. It is uncertain whether fibrin glue with the Karydakis flap affects the incidence of postoperative seroma (adverse event) (RR 3.00, 95% CI 0.67 to 13.46) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for imprecision). Fibrin glue as an adjunct to Karydakis flap may reduce length of stay but this is highly uncertain (mean 2 days versus 3.7 days; P < 0.001, low-quality evidence downgraded twice for risk of selection, performance and detection bias). AUTHORS' CONCLUSIONS: Current evidence is uncertain regarding any benefits associated with fibrin glue either as monotherapy or as an adjunct to surgery for people with pilonidal sinus disease. We identified only four RCTs and each was small and at risk of bias resulting in very low-quality evidence for the primary outcomes of time to healing and adverse events. Future studies should enrol many more participants, ensure adequate randomisation and blinding, whilst measuring clinically relevant outcomes.

Gabapentin for the hemodynamic response to intubation: systematic review and meta-analysis.

PURPOSE: Endotracheal intubation is the gold standard for securing the airway before surgery. Nevertheless, this procedure can produce an activation of the sympathetic nervous system and result in a hemodynamic response which, in high-risk patients, may lead to cardiovascular instability and myocardial ischemia. The aim of this review was to evaluate whether gabapentin can attenuate this response and whether such an attenuation could translate into reduced myocardial ischemia and mortality. SOURCE: We searched MEDLINE(®), EMBASE™, CINAHL, AMED, and unpublished clinical trial databases for randomized-controlled trials that compared gabapentin with control, fentanyl, clonidine, or beta blockers for attenuating the hemodynamic response to intubation. Primary outcomes were mortality, myocardial infarction, and myocardial ischemia. Secondary outcomes were hemodynamic changes following intubation. PRINCIPAL FINDINGS: We included 29 randomized trials with only two studies at low risk of bias. No data were provided for the primary outcomes and no studies included high-risk patients. The use of gabapentin resulted in attenuation in the rise in mean arterial blood pressure [mean difference (MD), -12 mmHg; 95% confidence interval (CI), -17 to -8] and heart rate (MD, -8 beats·min(-1); 95% CI, -11 to -5) one minute after intubation. Gabapentin also reduced the risk of hypertension or tachycardia requiring treatment (risk ratio, 0.15; 95% CI, 0.05 to 0.48). Data were limited on adverse hemodynamic events such as bradycardia and hypotension. CONCLUSION: It remains unknown whether gabapentin improves clinically relevant outcomes such as death and myocardial infarction since studies failed to report on these. Nevertheless, gabapentin attenuated increases in heart rate and blood pressure following intubation when compared with the control group. Even so, the studies included in this review were at potential risk of bias. Moreover, they did not include high-risk patients or report adverse hemodynamic outcomes. Future studies are required to address these limitations.

Exploring the utility of bedside tests for predicting cardiorespiratory fitness in older adults.

Objectives: Cardiorespiratory fitness (CRF) declines with advancing and has also, independent of age, been shown to be predictive of all-cause mortality, morbidity, and poor clinical outcomes. In relation to the older patient, there is a particular wealth of evidence highlighting the relationship between low CRF and poor surgical outcomes. Cardiopulmonary exercise testing (CPET) is accepted as the gold-standard measure of CRF. However, this form of assessment has significant personnel and equipment demands and is not feasible for those with certain age-associated physical limitations, including joint and cardiovascular comorbidities. As such, alternative ways to assess the CRF of older patients are very much needed. Methods: Sixty-four participants (45% female) with a median age of 74 (65-90) years were recruited to this study via community-based advertisements. All participants completed three tests of physical function: (1) a step-box test; (2) handgrip strength dynamometry; and (3) a CPET on a cycle ergometer; and also had their muscle architecture (vastus lateralis) assessed by B-mode ultrasonography to provide measures of muscle thickness, pennation angle, and fascicle length. Multivariate linear regression was then used to ascertain bedside predictors of CPET parameters from the alternative measures of physical function and demographic (age, gender, body mass index (BMI)) data. Results: There was no significant association between ultrasound-assessed parameters of muscle architecture and measures of CRF. VO2peak was predicted to some extent from fast step time during the step-box test, gender, and BMI, leading to a model that achieved an R 2 of 0.40 (p < 0.001). Further, in aiming to develop a model with minimal assessment demands (i.e., using handgrip dynamometry rather than the step-box test), replacing fast step time with non-dominant HGS led to a model which achieved an R 2 of 0.36 (p < 0.001). Non-dominant handgrip strength combined with the step-box test parameter of fast step time and BMI delivered the most predictive model for VO2peak with an R 2 of 0.45 (p < 0.001). Conclusions: Our findings show that simple-to-ascertain patient characteristics and bedside assessments of physical function are able to predict CPET-derived CRF. Combined with gender and BMI, both handgrip strength and fast step time during a step-box test were predictive for VO2peak. Future work should apply this model to a clinical population to determine its utility in this setting and to explore if simple bedside tests are predictive of important clinical outcomes in older adults (i.e., post-surgical complications).

The time course of disuse muscle atrophy of the lower limb in health and disease.

Short, intermittent episodes of disuse muscle atrophy (DMA) may have negative impact on age related muscle loss. There is evidence of variability in rate of DMA between muscles and over the duration of immobilization. As yet, this is poorly characterized. This review aims to establish and compare the time-course of DMA in immobilized human lower limb muscles in both healthy and critically ill individuals, exploring evidence for an acute phase of DMA and differential rates of atrophy between and muscle groups. MEDLINE, Embase, CINHAL and CENTRAL databases were searched from inception to April 2021 for any study of human lower limb immobilization reporting muscle volume, cross-sectional area (CSA), architecture or lean leg mass over multiple post-immobilization timepoints. Risk of bias was assessed using ROBINS-I. Where possible meta-analysis was performed using a DerSimonian and Laird random effects model with effect sizes reported as mean differences (MD) with 95% confidence intervals (95% CI) at various time-points and a narrative review when meta-analysis was not possible. Twenty-nine studies were included, 12 in healthy volunteers (total n = 140), 18 in patients on an Intensive Therapy Unit (ITU) (total n = 516) and 3 in patients with ankle fracture (total n = 39). The majority of included studies are at moderate risk of bias. Rate of quadriceps atrophy over the first 14 days was significantly greater in the ITU patients (MD -1.01 95% CI -1.32, -0.69), than healthy cohorts (MD -0.12 95% CI -0.49, 0.24) (P < 0.001). Rates of atrophy appeared to vary between muscle groups (greatest in triceps surae (-11.2% day 28), followed by quadriceps (-9.2% day 28), then hamstrings (-6.5% day 28), then foot dorsiflexors (-3.2% day 28)). Rates of atrophy appear to decrease over time in healthy quadriceps (-6.5% day 14 vs. -9.1% day 28) and triceps surae (-7.8% day 14 vs. -11.2% day 28), and ITU quadriceps (-13.2% day 7 vs. -28.2% day 14). There appears to be variability in the rate of DMA between muscle groups, and more rapid atrophy during the earliest period of immobilization, indicating different mechanisms being dominant at different timepoints. Rates of atrophy are greater amongst critically unwell patients. Overall evidence is limited, and existing data has wide variability in the measures reported. Further work is required to fully characterize the time course of DMA in both health and disease.

Indicators of response to exercise training: a systematic review and meta-analysis.

BACKGROUND: Means-based analysis of maximal rate of oxygen consumption (VO2max) has traditionally been used as the exercise response indicator to assess the efficacy of endurance (END), high intensity interval (HIIT) and resistance exercise training (RET) for improving cardiorespiratory fitness and whole-body health. However, considerable heterogeneity exists in the interindividual variability response to the same or different training modalities. OBJECTIVES: We performed a systematic review and meta-analysis to investigate exercise response rates in the context of VO2max: (1) in each training modality (END, HIIT and RET) versus controls, (2) in END versus either HIIT or RET and (3) exercise response rates as measured by VO2max versus other indicators of positive exercise response in each exercise modality. METHODS: Three databases (EMBASE, MEDLINE, CENTRAL) and additional sources were searched. Both individual response rate and population average data were incorporated through continuous data, respectively. Of 3268 identified manuscripts, a total of 29 studies were suitable for qualitative synthesis and a further 22 for quantitative. Stratification based on intervention duration (less than 12 weeks; more than or equal to 12 weeks) was undertaken. RESULTS: A total of 62 data points were procured. Both END and HIIT training exhibited differential improvements in VO2max based on intervention duration. VO2max did not adequately differentiate between END and HIIT, irrespective of intervention length. Although none of the other exercise response indicators achieved statistical significance, LT and HRrest demonstrated common trajectories in pooled and separate analyses between modalities. RET data were highly limited. Heterogeneity was ubiquitous across all analyses. CONCLUSIONS: The potential for LT and HRrest as indicators of exercise response requires further elucidation, in addition to the exploration of interventional and intrinsic sources of heterogeneity.