Low tidal volume ventilation for patients undergoing laparoscopic surgery: a secondary analysis of a randomised clinical trial.

BACKGROUND: We recently reported the results for a large randomized controlled trial of low tidal volume ventilation (LTVV) versus conventional tidal volume (CTVV) during major surgery when positive end expiratory pressure (PEEP) was equal between groups. We found no difference in postoperative pulmonary complications (PPCs) in patients who received LTVV. However, in the subgroup of patients undergoing laparoscopic surgery, LTVV was associated with a numerically lower rate of PPCs after surgery. We aimed to further assess the relationship between LTVV versus CTVV during laparoscopic surgery. METHODS: We conducted a post-hoc analysis of this pre-specified subgroup. All patients received volume-controlled ventilation with an applied PEEP of 5 cmH2O and either LTVV (6 mL/kg predicted body weight [PBW]) or CTVV (10 mL/kg PBW). The primary outcome was the incidence of a composite of PPCs within seven days. RESULTS: Three hundred twenty-eight patients (27.2%) underwent laparoscopic surgeries, with 158 (48.2%) randomised to LTVV. Fifty two of 157 patients (33.1%) assigned to LTVV and 72 of 169 (42.6%) assigned to conventional tidal volume developed PPCs within 7 days (unadjusted absolute difference, - 9.48 [95% CI, - 19.86 to 1.05]; p = 0.076). After adjusting for pre-specified confounders, the LTVV group had a lower incidence of the primary outcome than patients receiving CTVV (adjusted absolute difference, - 10.36 [95% CI, - 20.52 to - 0.20]; p = 0.046). CONCLUSION: In this post-hoc analysis of a large, randomised trial of LTVV we found that during laparoscopic surgeries, LTVV was associated with a significantly reduced PPCs compared to CTVV when PEEP was applied equally between both groups. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry no: 12614000790640.

A scoping review of assessment methods of competence of general surgical trainees.

BACKGROUND: Only rigorous evaluation of competence will result in the production of safe surgeons that are able to provide the best care for patients. The development of competency-based assessment should ultimately be evidence driven. OBJECTIVES: Explore the volume of existing evidence pertaining to the different objective assessment methods reported in the literature. ELIGIBILITY CRITERIA: Studies describing objective assessment of postgraduate general surgical trainees within the last 20 years. SOURCES OF EVIDENCE: PubMed, Ovid Medline and Web of Sciences. CHARTING METHODS: A data chart proforma was designed and data were extracted into tables. Basic numerical analysis of extracted data and narrative synthesis of charted data. RESULTS: A total of 343 papers were reviewed. 26 were eligible for inclusion. 92% of articles were published from 2008 onwards. 50% have been published in the last five years. The articles originated from 6 different countries, predominantly the United Kingdom (42%), followed by the United States of America (38%). In addition, a small number were published from Canada (8%), Japan (4%), Germany (4%) and Australia (4%). UK publications were predominantly between 2008 and 2014 while the USA had a later predominance between 2015 and 2018. 42% were based on quantitative methodology, 27% had a qualitative approach while 31% had mixed analysis. There were sixteen assessment methods presented. The most common type of assessment was Objective Structured Assessments (27%), which included Objective Structured Assessment of Technical Skill (OSATS) (23%) and Objective Structured Assessment of Non-Technical Skill (4%). Procedure Based Assessment (PBA) (23%) and Entrustability Scales (23%) were also prevalent. CONCLUSIONS: This scoping review has identified a range of different assessment methods. The assessment methods with a higher volume and level of supporting evidence were OSATS, PBAs and Entrustability Scales. There was a lower volume and level of supporting evidence found within this review for the remaining assessment methods.

Intraoperative low tidal volume ventilation and the risk of ICD-10 coded delirium and the use for antipsychotic medications.

BACKGROUND: Low tidal volume (VT) ventilation and its associated increase in arterial carbon dioxide (PaCO2) may affect postoperative neurologic function. We aimed to test the hypothesis that intraoperative low VT ventilation affect the incidence of postoperative ICD-10 coded delirium and/or the need for antipsychotic medications. METHODS: This is a post-hoc analysis of a large randomized controlled trial evaluating low vs. conventional VT ventilation during major non-cardiothoracic, non-intracranial surgery. The primary outcome was the incidence of ICD-10 delirium and/or the use of antipsychotic medications during hospital stay, and the absolute difference with its 95% confidence interval (CI) was calculated. RESULTS: We studied 1206 patients (median age of 64 [55-72] years, 59.0% males, median ARISCAT of 26 [19-37], and 47.6% of ASA 3). ICD-10 coded delirium and /or antipsychotic medication use was diagnosed in 11.2% with similar incidence between low and conventional VT ventilation (11.1% vs. 11.3%; absolute difference, -0.24 [95%CI, -3.82 to 3.32]; p = 0.894). There was no interaction between allocation group and type of surgery. CONCLUSION: In adult patients undergoing major surgery, low VT ventilation was not associated with increased risk of ICD-10 delirium and/or the use of antipsychotic medications during hospital stay. TRIAL REGISTRATION: ANZCTR Identifier: ACTRN12614000790640 .

Intra-operative ventilator mechanical power as a predictor of postoperative pulmonary complications in surgical patients: A secondary analysis of a randomised clinical trial.

BACKGROUND: Studies in critically ill patients suggest a relationship between mechanical power (an index of the energy delivered by the ventilator, which includes driving pressure, respiratory rate, tidal volume and inspiratory pressure) and complications. OBJECTIVE: We aimed to assess the association between intra-operative mechanical power and postoperative pulmonary complications (PPCs). DESIGN: Post hoc analysis of a large randomised clinical trial. SETTING: University-affiliated academic tertiary hospital in Melbourne, Australia, from February 2015 to February 2019. PATIENTS: Adult patients undergoing major noncardiothoracic, nonintracranial surgery. INTERVENTION: Dynamic mechanical power was calculated using the power equation adjusted by the respiratory system compliance (CRS). Multivariable models were used to assess the independent association between mechanical power and outcomes. MAIN OUTCOME MEASURES: The primary outcome was the incidence of PPCs within the first seven postoperative days. The secondary outcome was the incidence of acute respiratory failure. RESULTS: We studied 1156 patients (median age [IQR]: 64 [55 to 72] years, 59.5% men). Median mechanical power adjusted by CRS was 0.32 [0.22 to 0.51] (J min-1)/(ml cmH2O-1). A higher mechanical power was also independently associated with increased risk of PPCs [odds ratio (OR 1.34, 95% CI, 1.17 to 1.52); P < 0.001) and acute respiratory failure (OR 1.40, 95% CI, 1.21 to 1.61; P < 0.001). CONCLUSION: In patients receiving ventilation during major noncardiothoracic, nonintracranial surgery, exposure to a higher mechanical power was independently associated with an increased risk of PPCs and acute respiratory failure. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry no: 12614000790640.

Effect of Intraoperative Low Tidal Volume vs Conventional Tidal Volume on Postoperative Pulmonary Complications in Patients Undergoing Major Surgery: A Randomized Clinical Trial.

Importance: In patients who undergo mechanical ventilation during surgery, the ideal tidal volume is unclear. Objective: To determine whether low-tidal-volume ventilation compared with conventional ventilation during major surgery decreases postoperative pulmonary complications. Design, Setting, and Participants: Single-center, assessor-blinded, randomized clinical trial of 1236 patients older than 40 years undergoing major noncardiothoracic, nonintracranial surgery under general anesthesia lasting more than 2 hours in a tertiary hospital in Melbourne, Australia, from February 2015 to February 2019. The last date of follow-up was February 17, 2019. Interventions: Patients were randomized to receive a tidal volume of 6 mL/kg predicted body weight (n = 614; low tidal volume group) or a tidal volume of 10 mL/kg predicted body weight (n = 592; conventional tidal volume group). All patients received positive end-expiratory pressure (PEEP) at 5 cm H2O. Main Outcomes and Measures: The primary outcome was a composite of postoperative pulmonary complications within the first 7 postoperative days, including pneumonia, bronchospasm, atelectasis, pulmonary congestion, respiratory failure, pleural effusion, pneumothorax, or unplanned requirement for postoperative invasive or noninvasive ventilation. Secondary outcomes were postoperative pulmonary complications including development of pulmonary embolism, acute respiratory distress syndrome, systemic inflammatory response syndrome, sepsis, acute kidney injury, wound infection (superficial and deep), rate of intraoperative need for vasopressor, incidence of unplanned intensive care unit admission, rate of need for rapid response team call, intensive care unit length of stay, hospital length of stay, and in-hospital mortality. Results: Among 1236 patients who were randomized, 1206 (98.9%) completed the trial (mean age, 63.5 years; 494 [40.9%] women; 681 [56.4%] undergoing abdominal surgery). The primary outcome occurred in 231 of 608 patients (38%) in the low tidal volume group compared with 232 of 590 patients (39%) in the conventional tidal volume group (difference, -1.3% [95% CI, -6.8% to 4.2%]; risk ratio, 0.97 [95% CI, 0.84-1.11]; P = .64). There were no significant differences in any of the secondary outcomes. Conclusions and Relevance: Among adult patients undergoing major surgery, intraoperative ventilation with low tidal volume compared with conventional tidal volume, with PEEP applied equally between groups, did not significantly reduce pulmonary complications within the first 7 postoperative days. Trial Registration: ANZCTR Identifier: ACTRN12614000790640.

Frequency of hyperoxaemia during and after major surgery.

The oxygen concentration (FiO2) and arterial oxygen tension (PaO2) delivered in patients undergoing major surgery is poorly understood. We aimed to assess current practice with regard to the delivered FiO2 and the resulting PaO2 in patients undergoing major surgery. We performed a retrospective cohort study in a tertiary hospital. Data were collected prospectively as part of a larger randomised controlled trial but were analysed retrospectively. Patients were included if receiving controlled mandatory ventilation and arterial line monitoring. Anaesthetists determined the FiO2 and the oxygenation saturation (SpO2) targets. An arterial blood gas (ABG) was obtained 15-20 minutes after induction of anaesthesia, immediately before the emergence phase of anaesthesia and 15 minutes after arrival in the post-anaesthesia care unit (PACU). We defined hyperoxaemia as a PaO2 of >150 mmHg and included a further threshold of PaO2 >200 mmHg. We studied 373 patients. The median (interquartile range (IQR)) lowest intraoperative FiO2 and SpO2 values were 0.45 (IQR 0.4-0.5) and 97% (IQR 96-98%), respectively, with a median PaO2 on the first and second ABG of 237 mmHg (IQR 171-291 mmHg) and 189 mmHg (IQR 145-239 mmHg), respectively. In the PACU, the median lowest oxygen flow rate was 6 L/min (IQR 3-6 L/min), and the PaO2 was 158 mmHg (IQR 120-192 mmHg). Hyperoxaemia occurred in 82%, 73% and 54% of participants on the first and second intraoperative and postoperative ABGs respectively. A PaO2 of >200 mmHg occurred in 64%, 41% and 21% of these blood gases, respectively. In an Australian tertiary hospital, a liberal approach to FiO2 and PaO2 was most common and resulted in a high incidence of perioperative hyperoxaemia.

Cardiac Implantable Electronic Devices and End-of-Life Care: An Australian Perspective.

Cardiac implantable electronic devices (pacemakers and defibrillators) are increasingly common in modern cardiology practice, and health professionals from a variety of specialties will encounter patients with such devices on a frequent basis. This article will focus on the subset of patients who may request, or be appropriate for, device deactivation and discuss the issues surrounding end-of-life decisions, along with the ethical and legal implications of device deactivation.

Thymic flap for bronchial stump reinforcement after lobectomy.

Buttressing of the bronchial stump after pulmonary resection has been reported to decrease the prevalence of bronchopleural fistula. This adjuvant maneuver is most commonly performed in patients undergoing resection for infection or in those who have received preoperative radiation. The anatomic location of the upper lobe bronchus often makes it difficult to create a tension-free flap using muscle or pericardial fat. Parietal pleura is often mobilized for such cases. We present a case in which the parietal pleura was not available, and the right inferior pole of the thymus was used for bronchial coverage following upper lobectomy.

Portomesenteric venous thrombosis following major colon and rectal surgery: incidence and risk factors.

BACKGROUND: Portomesenteric venous thrombosis (PMVT) is an uncommon complication of abdominal surgery. The objective of this study was to assess PMVT risk factor profiles and patient outcomes after colorectal surgery. METHODS: A single center retrospective review of patients undergoing colorectal surgery was performed (2007-2012). PMVT was defined as thrombus within the portal, splenic, or superior mesenteric vein on computed tomography (CT). Inferior mesenteric vein thrombosis was excluded. Independent samples t test was used to compare data variables between PMVT and non-PMVT patients. Univariate and multivariate logistic regression analyses were used to assess PMVT risk factors. RESULTS: There were 1,224 patients included (mean age 62 years, male = 566). Elective bowel resection was performed for colon carcinoma (n = 302), rectal carcinoma (n = 112), ulcerative colitis (n = 125), Crohn's disease (n = 78), polyps (n = 117), and diverticulitis (n = 215). Patients undergoing gynecological resections and emergent laparotomies were included (n = 275). Thirty-six patients (3%) were diagnosed with PMVT by CT: 17/36 on initial presentation and 19/36 by expert radiologist review. Patients with PMVT were younger (53 vs. 62 years, p = 0.001) with higher BMI (30.5 vs. 26.7, p < 0.001) and thrombocytosis (464 vs. 306, p < 0.001) compared to patients without PMVT. Univariate logistic regression identified younger age (p < 0.001), obesity (p < 0.001), ulcerative colitis (p < 0.001), thrombocytosis, (p < 0.001) and proctocolectomy as significant predictors of PMVT. Stepwise multivariate logistic regression identified that obesity (p < 0.001), thrombocytosis, (p < 0.001) and restorative proctocolectomy (p = 0.001) were still significant predictors. No patients in the PMVT group suffered bowel infarction and no related mortalities occurred. Thirty-day readmission rates were higher in the PMVT group (53% vs. 17%, p < 0.01). CONCLUSION: BMI ≥ 30 kg/m(2), thrombocytosis, and restorative proctocolectomy were significant predictors of PMVT. Initial diagnostic studies showed a PMVT rate of 1.4%; however, after expert focused radiologic review, the actual rate was 3%. Thus, the diagnosis of PMVT is difficult and readmission after colorectal surgery should prompt its consideration.

Surgical and medical management of extracranial carotid artery aneurysms.

OBJECTIVE: Extracranial carotid artery aneurysms (ECCAs) are extremely rare with limited information about management options. Our purpose was to review our institution's experience with ECCAs during 15 years and to discuss the presentation and treatment of these aneurysms. METHODS: A retrospective review of patients diagnosed with ECCAs from 1998 to 2012 was performed. Symptoms, risk factors, etiology, diagnostic methods, treatments, and outcomes were reviewed. RESULTS: During the study period, 141 aneurysms were diagnosed in 132 patients (mean age, 61 years; 69 men). There were 116 (82%) pseudoaneurysms and 25 (18%) true aneurysms; 69 (49%) aneurysms were asymptomatic, whereas 72 (52%) had symptoms (28 painless masses; 10 transient ischemic attacks; 10 vision symptoms; 9 ruptures; 8 strokes; 4 painful mass; 1 dysphagia; 1 tongue weakness; 1 bruit). Causes of true aneurysms included fibromuscular dysplasia in 15 patients, Ehlers-Danlos syndrome in three, Marfan syndrome in one, and uncharacterized connective tissue diseases in two. Of 25 true aneurysms, 11 (44%) were symptomatic; 15 (60%) true aneurysms underwent open surgical treatment, whereas 10 (40%) were managed nonoperatively. Postoperative complications included one stroke during a mean follow-up of 31 months (range, 0-166 months). No aneurysms managed nonoperatively required intervention during a mean follow-up of 77 months (range, 1-115 months). Of 116 pseudoaneurysms, 60 (52%) were symptomatic; 33 (29%) pseudoaneurysms underwent open surgery, 18 (15%) underwent endovascular intervention, and 65 (56%) were managed medically. Pseudoaneurysm after endarterectomy (28 patients; 24%) presented at a mean of 82 months from the surgical procedure. Mean follow-up for all aneurysms was 33.9 months. One (0.7%) aneurysm-related death occurred (rupture treated palliatively). No patient undergoing nonoperative management suffered death or major morbidity related to the aneurysm. Nonoperative management was more common in asymptomatic patients (71%) than in symptomatic patients (31%). CONCLUSIONS: ECCAs are uncommon and may be manifested with varying symptoms. All segments of the carotid artery are susceptible, although the internal is most commonly affected. Open surgical intervention was more common in patients with symptoms and with true aneurysms. Patients with pseudoaneurysms were more likely to undergo endovascular intervention. Nonoperative treatment is safe in selected patients.

Brachiocephalic vein bypass with sternal reconstruction for symptomatic occlusion.

Complications attributed to central venous stenosis and subsequent thrombosis are increasing in frequency and are most commonly associated with neointimal fibroplasia as well as neoplastic, fibrotic, and traumatic pathologies. We present the successful venous bypass and thoracic wall reconstruction of a 58-year-old female with chronic atypical symptoms secondary to brachiocephalic vein occlusion from congenital thoracic dystrophy.

Do statins have a role in the promotion of postoperative wound healing in cardiac surgical patients?

Cardiac surgical patients often have associated comorbidities that can impede normal wound healing; however, statin therapy has the potential to improve this process through augmentation of the normal inflammatory response. Outcomes included a 30% earlier rate of wound epithelialization and an 80% greater wound-breaking strength combined with faster wound healing rates (13.0 days vs 18.7 days, p<0.0001). Inhibition of farnesyl pyrophosphate may hold a key role in the mediation of such advantageous effects. This systematic review suggests that there is sufficient evidence to warrant completion of a human trial to assess the effects of statins on wound healing.

A meta-analysis to compare Dacron versus polytetrafluroethylene grafts for above-knee femoropopliteal artery bypass.

BACKGROUND: Surgical revascularization for lower limb ischemia remains an important component for optimization of quality of life and symptoms in patients with peripheral arterial disease. In the absence of a vein graft, prosthetic alternatives are considered. The objective of this meta-analysis was to establish which prosthetic graft, Dacron or polytetrafluroethylene (PTFE), has the better long-term patency in patients undergoing an above-knee femoropopliteal arterial bypass. METHODS: This meta-analysis was performed by use of Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An electronic search of all relevant databases was performed from 1990 to 2013 with the Medical Subject Headings "Dacron," "polytetrafluroethylene," "PTFE," "above knee," "femoropopliteal," and "bypass" combined with the Boolean operator "AND." The inclusion criteria were randomized controlled trials, use of Dacron vs PTFE prosthetic conduits, and completion of an above-knee femoropopliteal arterial bypass involving adult patients older than 18 years presenting with disabling claudication, rest pain or tissue loss, occlusion of the superficial femoral artery, and reconstitution of the above-knee popliteal artery. Whenever studies included above- and below-knee data, only the above-knee arterial bypass data were extracted and analyzed. Graft patency rates were calculated with RevMan 5.1 software provided by the Cochrane Collaboration. RESULTS: Ninety-one publications were reviewed. After exclusion of duplicate, nonrandomized, and alternative bypass surgery studies, eight randomized controlled trials were identified and included in the meta-analysis. Two of the included trials represented follow-up evaluation of two previous studies, and for the purpose of this analysis, the initial and follow-up studies were subsequently evaluated as one trial. In this meta-analysis, 1192 patients were assessed, including 601 Dacron and 591 PTFE above-knee lower limb arterial bypasses. Primary patency was calculated from all included studies. However, only four studies provided data to evaluate secondary patency. Mean age reported was 66 years. Although all studies described cardiovascular comorbidities and risk factors including myocardial ischemia, diabetes, hypertension, and smoking, exact patient numbers were not consistently provided. Included studies evaluated grafts from 5 to 8 mm. Although primary and secondary patency rates at 12 months were not significantly different (relative risk [RR], 0.78; P = .08, and RR, 0.84; P = .52), 24-, 36-, and 60-month primary patency rates were significantly better with Dacron compared with PTFE grafts (RR, 0.79; P = .003; RR, 0.80; P = .03; RR, 0.85; P = .02). Statistical analysis also supported higher secondary patency rates for Dacron at 24 months (RR, 0.75; P = .02) and 60 months (RR, 0.76-0.77; P = .03-.27). Although primary patency was similar between grafts (28% vs 28%; P = .12), secondary patencies were better with Dacron at 10 years (49% vs 35%; P = .01). Antiplatelet and anticoagulation protocols varied between the trials. There was no difference in amputation, overall morbidity, or mortality rates between the two surgical graft populations. CONCLUSIONS: Current evidence suggests that Dacron prosthetic grafts are superior to PTFE grafts in above-knee femoropopliteal arterial bypass procedures. Further randomized trials targeting standardization of confounding variables, particularly graft size and best medical therapy, are warranted.

Endothelial function, antioxidant status and vascular compliance in newly diagnosed HFE C282Y homozygotes.

PURPOSE: This pilot study was aimed to establish techniques for assessing and observing trends in endothelial function, antioxidant status and vascular compliance in newly diagnosed HFE haemochromatosis during the first year of venesection. PATIENTS/METHODS: Untreated newly diagnosed HFE haemochromatosis patients were tested for baseline liver function, iron indices, lipid profile, markers of endothelial function, anti-oxidant status and vascular compliance. Following baseline assessment, subjects attended at 6-weeks and at 3, 6, 9 and 12-months for follow-up studies. RESULTS: Ten patients were recruited (M=8, F=2, mean age=51 years). Venesection significantly increased high density lipoproteins at 12-months (1.25 mmol/L vs. 1.37 mmol/L, p=0.01). However, venesection did not significantly affect lipid hydroperoxides, intracellular and vascular cell adhesion molecules or high sensitivity C-reactive protein (0.57 µmol/L vs. 0.51 µmol/L, p=0.45, 427.4 ng/ml vs. 307.22 ng/ml, p=0.54, 517.70 ng/ml vs. 377.50 ng/ml, p=0.51 and 290.75 µg/dL vs. 224.26 µg/dL, p=0.25). There was also no significant effect of venesection on anti-oxidant status or pulse wave velocity (9.65 m/s vs. 8.74 m/s, p=0.34). CONCLUSIONS: Venesection significantly reduced high density lipoproteins but was not associated with significant changes in endothelial function, anti-oxidant status or vascular compliance. Larger studies using this established methodology are required to clarify this relationship further.

Glomus tumor of the mediastinum.

Glomus tumors are rare benign myoepithelial neoplasms that can present with intractable pain. We report the case of a 59-year-old gentleman who presented with upper abdominal and chest pain caused by a posterior mediastinal glomus tumor arising from the spinal column, which required surgical resection. As glomus tumors usually develop in the limbs, this case highlights the complexity of diagnosis and treatment of glomus tumors when they present in rare locations.

Percutaneous thrombolysis of acute-on-chronic inferior vena cava thrombosis after previous insertion of an Adams-DeWeese clip.

We describe the successful percutaneous treatment of acute-on-chronic IVC thrombosis 30 years following previous placement of Adams-DeWeese clip.