Baseline Gastric Volume in Fasting Diabetic Patients Is Not Higher than That in Nondiabetic Patients: A Cross-sectional Noninferiority Study.

BACKGROUND: The physiology of diabetes mellitus can increase the risk of perioperative aspiration, but there is limited and contradictory evidence on the incidence of "full stomach" in fasting diabetic patients. The aim of this study is to assess the baseline gastric content (using gastric ultrasound) in diabetic and nondiabetic patients scheduled for elective surgery who have followed standard preoperative fasting instructions. METHODS: This was a prospective, noninferiority study of 180 patients (84 diabetic and 96 nondiabetic patients). Bedside ultrasound was used for qualitative and quantitative assessment of the gastric antrum in the supine and right lateral decubitus positions. Fasting gastric volume was estimated based on the cross-sectional area of the gastric antrum and a validated model. The hypothesis was that diabetic patients would not have a higher baseline fasting gastric volume compared to nondiabetic patients, with a noninferiority margin of 0.4 ml/kg. Secondary aims included the comparison of the incidence of full stomach (solid content or more than 1.5 mL/kg of clear fluid), estimation of the 95th percentile of the gastric volume distribution in both groups, and examination of the association between gastric volume, glycemic control, and diabetic comorbidities. RESULTS: The baseline gastric volume was not higher in diabetic patients (0.81 ± 0.61 ml/kg) compared to nondiabetic patients (0.87 ± 0.53 ml/kg) with a mean difference of -0.07 ml/kg (95% CI, -0.24 to 0.10 ml/kg). A total of 13 (15.5%) diabetic and 11 (11.5%) nondiabetic patients presented more than 1.5 ml/kg of gastric volume (95% CI for difference, -7.1 to 15.2%). There was little correlation between the gastric volume and either the time since diagnosis or HbA1C. CONCLUSIONS: The data suggest that the baseline gastric volume in diabetic patients who have followed standard fasting instructions is not higher than that in nondiabetic patients.

Ready to scan? A systematic review of point of care ultrasound (PoCUS) for screening of obstructive sleep apnea (OSA) in the pediatric population.

STUDY OBJECTIVE: Diagnosis of obstructive sleep apnea (OSA) in pediatric practice is challenging, as screening questionnaires are inadequate and sleep studies are resource limited and time-consuming. A recent systematic review and meta-analysis of perioperative point-of-care ultrasound (PoCUS) in adults identified several parameters which correlate with OSA diagnosis and are the subject of an ongoing prospective study. The objective of this systematic review was to evaluate the usefulness of surface airway ultrasound as a PoCUS tool for OSA screening in the pediatric population. DESIGN: Databases were searched for observational cohort studies and randomized controlled trials of patients under 18 years of age undergoing quantitative surface US measurement of extra-thoracic airway structures where correlation or association was examined either directly to OSA diagnosis or indirectly to an alternative reference measure. Diagnostic properties and correlation between US parameters (index test) and reference measures were evaluated where possible. MAIN RESULTS: Of the initial 8499 screened articles, 12 articles (8 airway, 4 non-airway) evaluating 1237 patients were included. Six of these studies were conducted in the sleep/obesity clinic and six in in the perioperative population. Ten studies were prospective and two were cross sectional studies. Airway parameters which correlated with moderate-severe OSA were lateral pharyngeal wall thickness and total neck thickness at the retropharyngeal level. Tonsil volume was not correlated with OSA diagnosis or severity. In tonsillectomy patients, tonsil volume on preoperative ultrasound correlated well with volume of surgical specimens. Adenoid thickness correlated strongly with radiological and endoscopic measures of size and occlusion. CONCLUSION: Ultrasound measurement in children indicates several parameters which correlate with OSA diagnosis or with other reference measurements. This has not yet been validated as a diagnostic tool, however the recent emergence of research in this area is encouraging and the findings from this review will inform future studies.

Role of regional anesthesia and analgesia in enhanced recovery after colorectal surgery: a systematic review of randomized controlled trials.

BACKGROUND: Effective analgesia is an important element of enhanced recovery after surgery (ERAS), but the clinical impact of regional anesthesia and analgesia for colorectal surgery remains unclear. OBJECTIVE: We aimed to determine the impact of regional anesthesia following colorectal surgery in the setting of ERAS. EVIDENCE REVIEW: We performed a systematic review of nine databases up to June 2020, seeking randomized controlled trials comparing regional anesthesia versus control in an ERAS pathway for colorectal surgery. We analyzed the studies with successful ERAS implementation, defined as ERAS protocols with a hospital length of stay of ≤5 days. Data were qualitatively synthesized. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. FINDINGS: Of the 29 studies reporting ERAS pathways, only 13 comprising 1170 patients were included, with modest methodological quality and poor reporting of adherence to ERAS pathways. Epidural analgesia had limited evidence of outcome benefits in open surgery, while spinal analgesia with intrathecal opioids may potentially be associated with improved outcomes with no impact on length of stay in laparoscopic surgery, though dosing must be further investigated. There was limited evidence for fascial plane blocks or other regional anesthetic techniques. CONCLUSIONS: Although there was variable methodological quality and reporting of ERAS, we found little evidence demonstrating the clinical benefits of regional anesthetic techniques in the setting of successful ERAS implementation, and future studies must report adherence to ERAS in order for their interventions to be generalizable to modern clinical practice. PROSPERO REGISTRATION NUMBER: CRD42020161200.

Overview of Innervation of Knee Joint.

Image-guided diagnostic block and radiofrequency ablation of the knee joint to manage pain require detailed understanding of joint innervation in relation to soft tissue and bony landmarks. In this article, the origin, course, and relationship to anatomic landmarks of articular nerves supplying the knee joint are discussed. The innervation pattern of the anterior and posterior aspects of the knee joint capsule is relatively consistent, with some variation in supply by the saphenous, anterior division of obturator, and common fibular nerves. To improve nerve capture rates for diagnostic block and radiofrequency ablation, multiple target sites could be beneficial.

Subomohyoid Anterior Suprascapular Block versus Interscalene Block for Arthroscopic Shoulder Surgery: A Multicenter Randomized Trial.

BACKGROUND: Interscalene brachial plexus block, the pain relief standard for shoulder surgery, is an invasive technique associated with important complications. The subomohyoid anterior suprascapular block is a potential alternative, but evidence of its comparative analgesic effect is sparse. The authors tested the hypothesis that anterior suprascapular block is noninferior to interscalene block for improving pain control after shoulder surgery. As a secondary objective, the authors evaluated the success of superior trunk (C5-C6 dermatomes) block with suprascapular block. METHODS: In this multicenter double-blind noninferiority randomized trial, 140 patients undergoing shoulder surgery were randomized to either interscalene or anterior suprascapular block with 15 ml of ropivacaine 0.5% and epinephrine. The primary outcome was area under the curve of postoperative visual analog scale pain scores during the first 24 h postoperatively. The 90% CI for the difference (interscalene-suprascapular) was compared against a -4.4-U noninferiority margin. Secondary outcomes included presence of superior trunk blockade, pain scores at individual time points, opioid consumption, time to first analgesic request, opioid-related side-effects, and quality of recovery. RESULTS: A total of 136 patients were included in the analysis. The mean difference (90% CI) in area under the curve of pain scores for the (interscalene-suprascapular) comparison was -0.3 U (-0.8 to 0.12), exceeding the noninferiority margin of -4.4 U and demonstrating noninferiority of suprascapular block. The risk ratio (95% CI) of combined superior trunk (C5-C6 dermatomes) blockade was 0.98 (0.92 to 1.01), excluding any meaningful difference in superior trunk block success rates between the two groups. When differences in other analgesic outcomes existed, they were not clinically important. CONCLUSIONS: The suprascapular block was noninferior to interscalene block with respect to improvement of postoperative pain control, and also for blockade of the superior trunk. These findings suggest that the suprascapular block consistently blocks the superior trunk and qualify it as an effective interscalene block alternative.

Intrathecal Morphine and Pulmonary Complications after Arthroplasty in Patients with Obstructive Sleep Apnea: A Retrospective Cohort Study.

BACKGROUND: Intrathecal morphine is commonly and effectively used for analgesia after joint arthroplasty, but has been associated with delayed respiratory depression. Patients with obstructive sleep apnea may be at higher risk of postoperative pulmonary complications. However, data is limited regarding the safety of intrathecal morphine in this population undergoing arthroplasty. METHODS: This retrospective cohort study aimed to determine the safety of intrathecal morphine in 1,326 patients with documented or suspected obstructive sleep apnea undergoing hip or knee arthroplasty. Chart review was performed to determine clinical characteristics, perioperative events, and postoperative outcomes. All patients received neuraxial anesthesia with low-dose (100 µg) intrathecal morphine (exposure) or without opioids (control). The primary outcome was any postoperative pulmonary complication including: (1) respiratory depression requiring naloxone; (2) pneumonia; (3) acute respiratory event requiring consultation with the critical care response team; (4) respiratory failure requiring intubation/mechanical ventilation; (5) unplanned admission to the intensive care unit for respiratory support; and (6) death from a respiratory cause. The authors hypothesized that intrathecal morphine would be associated with increased postoperative complications. RESULTS: In 1,326 patients, 1,042 (78.6%) received intrathecal morphine. The mean age of patients was 65 ± 9 yr and body mass index was 34.7 ± 7.0 kg/m. Of 1,326 patients, 622 (46.9%) had suspected obstructive sleep apnea (Snoring, Tired, Observed, Pressure, Body Mass Index, Age, Neck size, Gender [STOP-Bang] score greater than 3), while 704 of 1,326 (53.1%) had documented polysomnographic diagnosis. Postoperatively, 20 of 1,322 (1.5%) patients experienced pulmonary complications, including 14 of 1,039 (1.3%) in the exposed and 6 of 283 (2.1%) in the control group (P = 0.345). Overall, there were 6 of 1 322 (0.5%) cases of respiratory depression, 18 of 1,322 (1.4%) respiratory events requiring critical care team consultation, and 4 of 1,322 (0.3%) unplanned intensive care unit admissions; these rates were similar between both groups. After adjustment for confounding, intrathecal morphine was not significantly associated with postoperative pulmonary complication (adjusted odds ratio, 0.60 [95% CI, 0.24 to 1.67]; P = 0.308). CONCLUSIONS: Low-dose intrathecal morphine, in conjunction with multimodal analgesia, was not reliably associated with postoperative pulmonary complications in patients with obstructive sleep apnea undergoing joint arthroplasty.

Evaluation of the proximal adductor canal block injectate spread: a cadaveric study.

BACKGROUND AND OBJECTIVES: Quadriceps sparing adductor canal block has emerged as a viable intervention to manage pain after total knee arthroplasty. Recent studies have defined ultrasound (US) landmarks to localize the proximal and distal adductor canal. US-guided proximal adductor canal injection has not been investigated using these sonographic landmarks. The objectives of this cadaveric study were to evaluate dye injectate spread and quantify the capture rates of nerves supplying articular branches to the knee joint capsule using a proximal adductor canal injection technique. METHODS: A US-guided proximal adductor canal injection with 10 mL of dye was performed in seven lightly embalmed specimens. Following injection, specimens were dissected to document dye spread and frequency of nerve staining. RESULTS: Following proximal adductor canal injection, dye spread consistently stained the deep surface of sartorius, vastoadductor membrane, aponeurosis of the vastus medialis obliquus, and adductor canal. The saphenous nerve, posteromedial branch of nerve to vastus medialis, superior medial genicular nerve and genicular branch of obturator nerve were captured in all specimens at the proximal adductor canal. There was minimal to no dye spread to the distal femoral triangle, anterior division of the obturator nerve and anterior branches of nerve to vastus medialis. CONCLUSIONS: This anatomical study provides some insights into the mechanism of analgesia to the knee following a proximal adductor canal injection and its motor sparing properties. Further clinical investigation is required to confirm cadaveric findings.

Anterior quadratus lumborum block analgesia for total hip arthroplasty: a randomized, controlled study.

BACKGROUND AND OBJECTIVES: Quadratus lumborum (QL) block is a new regional analgesic technique for upper and lower abdominal surgeries as part of a multimodal analgesic regime. It has also been reported to relieve pain after total hip arthroplasty (THA). In this prospective, randomized, double-blind study, we compared QL block with control (no block) in patients undergoing primary THA. METHODS: Eighty patients undergoing primary THA surgery under spinal anesthesia were randomized into two groups, one with and one without QL block. The patients in both groups were randomized after sedation, positioning and ultrasound scanning. Both the patient and the researcher collecting data were blinded to the patient's group assignment. Opioid consumption and visual analog scores (VAS) pain scores were measured at 12, 24, and 48 hours after surgery. Also, the ambulation distance, patient satisfaction, and length of stay were recorded. RESULTS: The study analysis included 36 patients in the QL group and 35 patients in the control group. Both VAS pain score at 24 hours (difference -1.76, 95% CI -2.87 to -0.64) and cumulative opioid consumption were significantly lower in the QL group at 12, 12-24, 24, 24-48, and 48 hours after surgery as compared with the control group (difference at 48 hours -36.13, 95% CI -62.89 to -9.37) (p<0.05). However, there was no difference in pain score at 12 and 48 hours, nor in the ambulation distance and duration of hospital stay between the two groups. The patient satisfaction score was significantly higher in the QL group. CONCLUSIONS: Our preliminary data show that the QL block provided effective analgesia and decreased opioid requirements up to 48 hours after primary THA. TRIAL REGISTRATION NUMBER: NCT03408483.

Intermittent bolus versus continuous infusion popliteal sciatic nerve block following major foot and ankle surgery: a prospective randomized comparison.

BACKGROUND AND OBJECTIVES: Foot and ankle surgery is associated with severe pain that can be reduced with continuous popliteal sciatic nerve block. We tested the hypothesis that programmed intermittent bolus (PIB) delivery of local anesthetic provides superior analgesia to a continuous infusion (CI) regimen. METHODS: 60 patients undergoing major foot and ankle surgery were randomized to receive PIB (10 mL of ropivacaine 0.2% every 2 hours) or CI (5 mL/hour) continuous popliteal sciatic nerve block with patient-controlled regional analgesia (5 mL every 30 min as needed) provided for all. Primary outcome was the average of static and dynamic numerical rating scale (NRS) pain scores through 48 hours. Secondary outcomes included rest and movement NRS pain scores at different timepoints, opioid consumption, local anesthetic consumption, intensity of sensory and motor block, patient satisfaction and the incidence of opioid-related side effects. RESULTS: There was no significant difference in the primary outcome of average NRS pain score through 48 hours, opioid consumption or the volume of local anesthetic administered. Patients in group PIB had significantly decreased strength of toe dorsiflexion at 6 hours (p=0.007) and 12 hours (p=0.001) and toe plantarflexion at 12 hours (p=0.004). Patient satisfaction and the incidence of side effects was similar between groups. CONCLUSIONS: Both CI and PIB regimens provided excellent analgesia, low opioid consumption and high patient satisfaction. While there was no difference in analgesic outcomes, PIB dosing resulted in a more profound motor block. TRIAL REGISTRATION NUMBER: NCT02707874.

Addition of dexamethasone to local infiltration analgesia in elective total hip arthroplasty: a double-blind, randomized control trial.

BACKGROUND AND OBJECTIVES: Pain following total hip arthroplasty is significant, and effective analgesia is associated with an improvement in functional outcomes. Dexamethasone may facilitate the action of local anesthesia, but its role as an additive to a local infiltration analgesia (LIA) mixture in hip arthroplasty settings has not been investigated. We hypothesized that the addition of dexamethasone to local anesthetic infiltration improves analgesic outcomes following total hip arthroplasty. METHODS: We performed a double-blind, randomized control trial of 170 patients undergoing total hip arthroplasty. Patients were randomized to receive LIA mixed with either 2 mL of saline 0.9% or 2 mL of dexamethasone 4 mg/mL. The primary outcome was 24 hours oral morphine consumption. Secondary outcomes included short-term and long-term analgesic and functional outcomes and adverse events. RESULTS: 85 patients were included in each arm. 24 hours morphine consumption was similar between saline and dexamethasone groups, with a median (IQR (range)) of 75 (45-105 (0-240)) and 62.5 (37.5-102.5 (0-210)) mg, respectively (p=0.145). However, patients receiving dexamethasone had significantly reduced opioid consumption for their total in-hospital stay, but not at any other time points examined. Functional outcomes were similar between groups. The incidence of postoperative nausea and vomiting was reduced in patients receiving dexamethasone. CONCLUSIONS: The addition of 8 mg dexamethasone to LIA did not reduce 24 hours morphine consumption but was associated with limited improvement in short-term analgesic outcomes and a reduction in postoperative nausea and vomiting. Dexamethasone had no effect on functional outcomes or long-term analgesia. TRIAL REGISTRATION NUMBER: NCT02760043.

The effect of anesthetic technique on mortality and major morbidity after hip fracture surgery: a retrospective, propensity-score matched-pairs cohort study.

INTRODUCTION: Spinal anesthesia (SA) has physiological benefits over general anesthesia (GA), but there is insufficient evidence regarding a mortality benefit. We performed a retrospective propensity score-matched cohort study to evaluate the impact of anesthetic technique on mortality and major morbidity in patients undergoing hip fracture surgery. MATERIALS AND METHODS: Clinical, laboratory and outcome data were extracted from electronic databases for patients who underwent hip fracture surgery over a 13-year period at the University Health Network in Toronto, Ontario, Canada. The anesthetic technique was documented (SA or GA), and the primary outcome was 90-day mortality. Secondary outcomes included mortality at 30 and 60 days, hospital length of stay, pulmonary embolism (PE), major blood loss and major acute cardiac events. A propensity-score matched-pair analysis was performed following a non-parsimonious logistic regression model. RESULTS: Of the 2591 patients identified, 883 patients in the SA group were matched to patients in the GA group in a 1:1 ratio. There was a weak association between SA and lower 90-day mortality (risk ratio (RR) 0.74, 95% CI 0.52 to 0.96, 99% CI 0.48 to 1.00, p=0.037). SA was also associated with a lower incidence of both PE (1.3% vs 0.5%, p<0.001) and major blood loss (7.7% vs 4.8%, p<0.001) and a shorter hospital length of stay by about 2 days (median 11.9 vs 10 days, p=0.024). There was no difference in major cardiac events or mortality at 30 and 60 days. DISCUSSION: This propensity-score matched-pairs cohort study suggests that SA is weakly associated with a lower 90-day mortality following hip fracture surgery. SA was also associated with improved morbidity evidenced by a lower rate of PE and major blood loss and a shorter hospital length of stay. Given the retrospective nature of the study, these results are not proof of causality.

Ultrasound-guided transmuscular quadratus lumborum block for elective cesarean section significantly reduces postoperative opioid consumption and prolongs time to first opioid request: a double-blind randomized trial.

BACKGROUND: Elective cesarean section (ECS) can cause moderate to severe pain that often requires opioid administration. To enhance maternal recovery, and promote mother and baby interaction, it is important to reduce postoperative pain and opioid consumption. Various regional anesthesia techniques have been implemented to improve postoperative pain management following ECS. This study aimed to investigate the efficacy of bilateral ultrasound-guided transmuscular quadratus lumborum (TQL) block on reducing postoperative opioid consumption following ECS. METHODS: A randomized double-blind trial with concealed allocation was conducted in 72 parturients who received bilateral TQL block with either 30 mL ropivacaine 0.375% or saline. TQL block injectate was deposited in the interfascial plane between the quadratus lumborum and psoas major muscles, posterior to the transversalis fascia. Primary outcome was opioid consumption, which was recorded electronically. Pain scores and time to first opioid request were also evaluated. RESULTS: Opioid consumption (oral morphine equivalents, OME) was significantly reduced in group ropivacaine (GRO) in the first 24 hours compared with group saline (65 mg OME vs 94 mg OME) with a mean difference of 29 mg OME; 95% CI 3 to 55, p<0.03. Time to first opioid request was significantly prolonged in GRO, p<0.003. Numerical rating scale pain scores were significantly lower in GRO in the first 6 hours after surgery, p<0.03. CONCLUSIONS: Bilateral TQL block significantly reduced 24 hours' opioid consumption. Further, we observed significant prolongation in time to first opioid, and significant reduction of pain during the first 6 postoperative hours.

The analgesic efficacy of the transversalis fascia plane block in iliac crest bone graft harvesting: a randomized controlled trial.

BACKGROUND: Iliac crest bone graft (ICBG) harvesting is associated with significant perioperative pain and opioid consumption. This randomized controlled trial sought to determine if the transversalis fascia plane (TFP) block provides effective analgesia for anterior ICBG harvesting. METHODS: Fifty patients undergoing wrist fusion surgery with anterior ICBG harvesting were randomized to receive a TFP block with either 20 ml of 0.5% ropivacaine or 5% dextrose. Patients additionally received a brachial plexus block for primary surgical-site anesthesia and either a general or spinal anesthetic depending on patient preference. Primary outcomes of interest were perioperative opioid consumption (measured as intravenous morphine equivalents [IME]), pain intensity at the ICBG harvest site for up to 48 h postoperatively, and the incidence of persistent postoperative pain at 6 and 12 months after surgery. RESULTS: The TFP group used less opioid in the post-anesthetic care unit (PACU) (median 0 vs. 2.5 mg IME, P = 0.01) and in the first 8 h following PACU discharge (median 2.5 vs. 13.0 mg IME, P = 0.02). The patients who received a TFP block also had lower pain scores in PACU (median 0 vs. 4.0 out of 10, P < 0.001). Although opioid consumption and pain scores were lower in the TFP group at later timepoints, this difference was not statistically significant. Persistent pain at the ICBG site was reported in only 4.3% and 6.5% of all patients at 6 and 12 months, respectively. CONCLUSIONS: The TFP block provides effective early analgesia for anterior ICBG harvesting. The incidence of persistent postoperative pain was low.

Outcome Selection and Methodological Quality of Major and Minor Shoulder Surgery Studies: A Scoping Review.

BACKGROUND: Core outcome sets aim to select and standardize the choice of important outcomes reported in clinical trials to encourage more effective data synthesis, increase the reliability of comparing results, and minimize reporting bias. A core outcome set for elective shoulder surgery has yet to be defined, and therefore a systematic assessment of outcomes and methodology is necessary to inform the development of a core outcome set. QUESTIONS/PURPOSES: The purpose of this study was to examine randomized controlled trials (RCTs) of patients having elective major or minor shoulder surgery to (1) identify the outcome domains reported; (2) determine specific outcome measurement tools that were utilized; and (3) assess the work for methodological quality and risk of bias. METHODS: We conducted a scoping review (a review that identifies the nature and extent of research evidence) to explore the reported outcome domains, outcome tools, and methodological quality from RCTs conducted in shoulder surgery. We considered both major shoulder surgery (defined as arthroplasty, rotator cuff repair, stabilization procedures, biceps tenodesis, or Bankart repairs) and minor shoulder surgery (simple arthroscopy, capsular plication, lateral clavicular excisions, or subacromial decompression). We queried 10 electronic databases for studies published between January 2006 and January 2015. Studies were included if they were prospective, randomized controlled, clinical trials enrolling patients who received an elective shoulder surgical intervention. We extracted data relating to trial characteristics, primary outcomes, tools used to measure these outcomes as well as methodological quality indicators. We assessed indicators of methodological quality by exploring (1) the reproducibility of power analyses; and (2) whether the primary outcomes were powered to minimum clinically important differences. Risk of bias was also assessed with the Jadad score with scores between 0 (very high risk of bias) and 5 (very low risk). Findings were qualitatively analyzed and reported according to systematic and scoping review guidelines. We included 315 studies involving 30,232 patients; 266 studies investigated anesthetic, analgesic, or surgical interventions. RESULTS: Of the 315 studies included, the most common outcome domains evaluated were analgesic (n = 104), functional (n = 87), anesthetic (n = 56), and radiologic (n = 29) outcomes, with temporal patterns noted. Studies of major shoulder surgery most commonly reported functional primary outcome domains, whereas minor shoulder surgery studies most frequently reported analgesic primary outcome domains. There were 85 different primary outcome tools utilized, which included 20 functional, 20 anesthetic, 13 analgesic, and 12 radiologic. A methodological quality assessment revealed that 24% of studies had reproducible power analyses, 13% were powered to minimum clinically important differences, and risk of bias assessment demonstrated a median (interquartile range [range]) Jadad score of 4 (3-5 [1-5]). CONCLUSIONS: A wide range of outcome domains and outcome assessment tools are in common use in contemporary trials of patients undergoing elective surgery. Although some diversity is important to allow the assessment of patient populations that may have different goals, the large number of tools in common use may impair the ability of future meta-analyses to pool results effectively or even for systematic reviews to synthesize what is known. The limitations of methodological quality in RCTs may be improved by researchers following standard guidelines and considering the minimum clinically important differences in their trials to be of greater use to clinicians and their patients. LEVEL OF EVIDENCE: Level I, therapeutic study.

Diagnostic Accuracy of Point-of-Care Gastric Ultrasound.

BACKGROUND: Pulmonary aspiration of gastric contents is associated with significant perioperative morbidity and mortality. Previous studies have investigated the validity, reliability, and possible clinical impact of gastric ultrasound for the assessment of gastric content at the bedside. In the present study, we examined the accuracy (evaluated as sensitivity, specificity, and likelihood ratios) of point-of-care gastric ultrasound to detect a "full stomach" in a simulated scenario of clinical equipoise. METHODS: After a minimum fasting period of 8 hours, 40 healthy volunteers were randomized in a 1:1 ratio to either remain fasted or ingest a standardized quantity of clear fluid or solid. Each subject was randomized twice on 2 independent study sessions at least 24 hours apart. A gastric ultrasound examination was performed by a blinded sonographer following a standardized scanning protocol. Using a combination of qualitative and quantitative findings, the result was summarized in a dichotomous manner as positive (any solid or >1.5 mL/kg of clear fluid) or negative (no solid and ≤1.5 mL/kg of clear fluid) for full stomach. RESULTS: Data from 80 study sessions were analyzed. In this simulated clinical scenario with a pretest probability of 50%, point-of-care gastric ultrasound had a sensitivity of 1.0 (95% confidence interval [CI], 0.925-1.0), a specificity of 0.975 (95% CI, 0.95-1.0), a positive likelihood ratio of 40.0 (95% CI, 10.33-∞), a negative likelihood ratio of 0 (95% CI, 0-0.072), a positive predictive value of 0.976 (95% CI, 0.878-1.0), and a negative predictive value of 1.0 (95% CI, 0.92-1.0). CONCLUSIONS: Our results suggest that bedside gastric ultrasound is highly sensitive and specific to detect or rule out a full stomach in clinical scenarios in which the presence of gastric content is uncertain.