Peri-operative management of the obese surgical patient 2015: Association of Anaesthetists of Great Britain and Ireland Society for Obesity and Bariatric Anaesthesia

Adopting the day surgery default in the provision of lumbar discectomy and decompressive surgery

INTRODUCTION

Provision of day case spinal procedures in the UK is below expected standards and there is a need for the creation of guidance and patient pathways to address this. Here we present a day case lumbar discectomy protocol and evaluate its impact at our institution.

METHODS

A new pathway (incorporating defined selection criteria, patient education, anaesthetic protocol and discharge prescriptions) was implemented for all suitable patients within a single surgeon's cohort. Day case rates for lumbar discectomy were compared before and after implementation. Patient feedback was collated using a patient-reported experience measure.

RESULTS

Eighteen of 23 patients selected as suitable via the pathway successfully underwent day surgery, leading to an increase in lumbar discectomy day case rates from 25% to 69% at our institution. Nearly all patients were satisfied with their experience, although a significant proportion felt provision of postoperative analgesia could be improved.

CONCLUSION

We present a day surgery pathway for lumbar discectomy that is safe and effective. This could be more widely implemented to increase day case rates.

Comparing postinduction hypoxemia between ramped and supine position endotracheal intubations with apneic oxygenation in the emergency department

INTRODUCTION

Ramped position and apneic oxygenation are strategies to mitigate hypoxemia; however, the benefits of these strategies when utilized together remain unclear. Therefore, we compared first-attempt, postinduction hypoxemia between adult emergency department (ED) endotracheal intubations performed with apneic oxygenation in the ramped versus supine positions.

METHODS

We used the National Emergency Airway Registry (NEAR), a multicenter registry of data on ED intubations from 25 academic and community sites. We included first-attempt intubations with direct (DL) and video (VL) laryngoscopy in subjects ≥ 18 years old with nontrauma indications receiving apneic oxygenation. We examined patient characteristics (e.g., sex, obesity) and key intubation outcomes, including hypoxemia (primary outcome), first-pass success, and other adverse events (e.g., bradycardia). In addition, we examined unadjusted odds ratios (OR) and adjusted ORs (aOR) for key variables and stratified by laryngoscope type.

RESULTS

We included 210 ramped cases and 1,820 supine cases in the DL cohort and 202 ramped and 1,626 supine cases in the VL cohort. Rates of postinduction hypoxemia were similar between supine and ramped position in both the DL cohort (supine 6.5% and ramped 7.6%, aOR [95% CI] = 0.96 [0.55 to 1.67]) and the VL cohort (supine 10.1% and ramped 12.4%, aOR [95% CI] = 0.97 [0.60 to 1.56]). Other outcomes were also similar between groups.

CONCLUSION

Using this large national data set, we did not identify a difference in postinduction hypoxemia between ramped and supine positions in this cohort of ED intubations with apneic oxygenation.

Guidelines for Perioperative Care in Bariatric Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations: A 2021 Update

Background

This is the second updated Enhanced Recovery After Surgery (ERAS®) Society guideline, presenting a consensus for optimal perioperative care in bariatric surgery and providing recommendations for each ERAS item within the ERAS® protocol.

Methods

A principal literature search was performed utilizing the Pubmed, EMBASE, Cochrane databases and ClinicalTrials.gov through December 2020, with particular attention paid to meta-analyses, randomized controlled trials and large prospective cohort studies. Selected studies were examined, reviewed and graded according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. After critical appraisal of these studies, the group of authors reached consensus regarding recommendations.

Results

The quality of evidence for many ERAS interventions remains relatively low in a bariatric setting and evidence-based practices may need to be extrapolated from other surgeries.

Conclusion

A comprehensive, updated evidence-based consensus was reached and is presented in this review by the ERAS® Society.

Postoperative Respiratory Compromise following Cesarean Birth: The Impact of Obesity and Systemic Opioids

Objective  The aim of this study was to measure the effect of obesity and systemic opioids on respiratory events within the first 24 hours following cesarean. Methods  Opioid-naive women undergoing cesarean between January 2016 and December 2017 were included in this retrospective cohort study. The primary outcome was the proportion of women experiencing at least one composite respiratory outcome (oxygen saturation less than 95% lasting 30+ seconds or need for respiratory support) within 24 hours of cesarean. The impact of obesity and total systemic opioid dose in 24 hours (measured in morphine milligram equivalents [MMEs]) on the composite respiratory compromise outcome were evaluated. Results  Of 2,230 cesarean births, 790 women had at least one composite respiratory event. Predictors of the composite respiratory outcome included body mass index (BMI) as a continuous variable (odds ratio = 1.063 for every one unit increase in BMI [95% confidence interval (CI): 1.021-1.108], p  = 0.003), and MME (odds ratio = 1.005 [95% CI: 1.002-1.008], p  = 0.003), adjusting for magnesium sulfate use. The interaction between obesity and opioid dose demonstrated an odds ratio of 1.000 (95% CI: 0.999-1.000, p  = 0.030). Conclusion  The proportion of women experiencing respiratory events following cesarean birth increases with the degree of obesity and opioid dose. Key Points Respiratory events increase with obesity.Respiratory events increase with systemic opioid use.Odds ratio of respiratory events is 1.063/unit BMI increase.

Airway management in patients with obesity

Airway management in patients with obesity remains a complex and evolving topic that is becoming more pertinent given the increasing prevalence of obesity and bariatric surgery worldwide. Obesity is associated with increased morbidity and mortality secondary to anesthetic complications, especially related to airway management. Preoperative assessment is especially vital for the bariatric patient so that potential predictors for a difficult airway can be identified. There are several airway management strategies and techniques for the bariatric population that may help reduce postoperative pulmonary complications. This review aims to discuss assessment of the airway, ideal patient positioning, intubation techniques and devices, apneic oxygenation, optimal ventilation strategies, and extubation and post-anesthesia care.

High-flow nasal cannula versus face mask for preoxygenation in obese patients: A randomised controlled trial

BACKGROUND

Preoxygenation efficacy with high-flow nasal cannula (HFNC) in obese patients is not clearly established. The primary aim of this study was to compare heated, humidified, high-flow nasal cannula with face mask for preoxygenation in this population.

METHODS

We conducted a single-centre, randomised, controlled trial. Forty subjects with BMI ≥ 35 kg m^-2 were randomly assigned to receive 5.0 min of preoxygenation with face mask and 7 cm H₂ O of PEEP (PEEP group) or HFNC at 70 L min^-1 (HF group). Following induction, bag-mask ventilation continued until laryngoscopy, whereas HFNC was maintained before and during intubation. The primary outcomes were end-tidal fraction of oxygen (EtO₂ ) at 2.5 and 5.0 min duration of preoxygenation. Secondary outcomes included PaO₂ and PaCO₂ at 2.5 and 5.0 min of preoxygenation and at intubation.

RESULTS

Mean (±SD) EtO₂ was 0.89 (±0.04) versus 0.90 (±0.05) after 2.5 min (95% CI for mean difference -0.02, 0.04) and 0.93 (±0.02) versus 0.91 (±0.02) after 5.0 min of preoxygenation (95% CI for mean difference -0.03, -0.002) in the PEEP (n = 18) and HF group (n = 20), respectively. All subjects reached an EtO₂  ≥ 0.85 at 5.0 min. There were no differences in mean PaO₂ or PaCO₂ during preoxygenation. Subjects in the HF group had a mean (±SD) apnoea time of 199 (±38) s, but no desaturation (SpO₂  < 100%) occurred.

CONCLUSIONS

Face mask with PEEP was superior to HFNC for preoxygenation in obese subjects. HFNC provided adequate preoxygenation quality in all subjects and may be considered as an alternative to face mask in selected patients.

TRIAL REGISTRATION

#ISRCTN37375068 (www.isrctn.com).

Prevalence of PErioperAtive CHildhood obesitY in children undergoing general anaesthesia in the UK: a prospective, multicentre, observational cohort study

BACKGROUND

Childhood obesity has become a serious global healthcare challenge. No UK data currently define its anaesthetic and perioperative implications. We aimed to determine obesity prevalence amongst UK children undergoing general anaesthesia and the incidence of predefined adverse perioperative events, and to compare perioperative obesity rates with National Child Measurement Programme (NCMP) data.

METHODS

During a site-selected consecutive 7-day study period, all children (2-16 yr) undergoing general anaesthesia were included. Anonymised hospital, surgical, and procedural details; demographic data; and adverse perioperative events were collected prospectively by Paediatric Anaesthesia Trainee Research Network (PATRN) collaborators.

RESULTS

For this study, 102 UK hospitals participated and 4232 cases were included in the final analysis; 76% of hospitals did not routinely calculate BMI. In addition, 3030 (71.6%; 95% confidence interval [CI]: 70.2-73.0%) children of healthy weight were compared with 537 (12.7%; 11.7-13.7%) children who were overweight and 478 (11.3%; 10.3-12.2%) children with obesity. Children with obesity (n=71; 14.9%) more commonly underwent (adeno)tonsillectomy than children of healthy weight (n=282; 9.3%; P<0.001; odds ratio [OR] 2.15; 95% CI: 1.58-2.92). Fewer children with obesity (n=365; 77% vs n=2552; 85%) were anaesthetised by consultant anaesthetists (OR 0.62; 95% CI: 0.48-0.79). Mask ventilation was difficult for 3.7% of children with obesity vs 0.6% of children of healthy weight (difference 3.0%; 95% CI: 1.3-4.7%; P<0.001). Comparison with NCMP data demonstrated an over-representation of obesity amongst the paediatric surgical population.

CONCLUSIONS

This large multicentre cohort study suggests a concerning prevalence of children with obesity presenting for anaesthesia. These results should be used to inform optimal provision of care for this population and support perioperative healthcare initiatives to address the burden of childhood obesity.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03994419.

Demographic and clinical factors associated with variations in opioid administration using conscious sedation during HDR brachytherapy for cervical cancer

PURPOSE/OBJECTIVES To examine patient characteristics that predispose to higher opioid administration during tandem and ovoid (T&O) high-dose rate (HDR) brachytherapy. METHODS A single-institution retrospective review was performed on patients who underwent brachytherapy for cervical cancer. Patients were included if they received at least one fraction of HDR T&O brachytherapy with analgesia administration recorded in the Medication Administration Record. Fentanyl dose was dichotomized as "low" (mean <125 μg per fraction), or "high" (mean ≥ 125 μg per fraction). Descriptive statistics and multiple logistic regression analysis were performed comparing mean opioid dose per fraction with demographic and clinical information. RESULTS From July 2014 through May 2020, 113 patients underwent 531 T&O HDR brachytherapy fractions with oral benzodiazepine and intravenous opioid fentanyl for conscious sedation. The median opioid dose per fraction was 100 μg fentanyl (range 0-250 μg). Using multiple logistic regression analysis, younger age (OR 1.071, p = 0.002) and higher BMI (OR 1.091, p = 0.019) were associated with increased opioid administration during brachytherapy. Black women received less opioid during brachytherapy when compared to White women (OR 0.296, p = 0.047). FIGO stage, ECOG score, smoking status, prior narcotic use, prior illicit drug use, parity, prior cervical procedure, Smit sleeve placement, and distance to treatment center were not associated with high opioid dose. CONCLUSION Cervical cancer patients who are younger or have higher BMI receive more narcotic analgesia during HDR brachytherapy whereas Black women received less narcotic analgesia, irrespective of age and BMI. This underscores the immediate need to address how pain is assessed and managed during brachytherapy.

Leading Causes of Anesthesia-Related Liability Claims in Ambulatory Surgery Centers

OBJECTIVE

We present a contemporary analysis of patient injury, allegations, and contributing factors of anesthesia-related closed claims, which involved cases that specifically occurred in free-standing ambulatory surgery centers (ASCs).

METHODS

We examined ASC-closed claims data between 2007 and 2014 from The Doctors Company, a medical malpractice insurer. Findings were coded using the Comprehensive Risk Intelligence Tool developed by CRICO Strategies. We compared coded data from ASC claims with hospital operating room (HOR) claims, in terms of injury severity category, nature of injury, nature of allegation, contributing factors identified, and contributing comorbidities and claim value.

RESULTS

Ambulatory surgery center claims were more likely to be classified as medium severity than HOR claims, more likely to involve dental damage or pain than HOR claims, but less likely to involve death or respiratory or cardiac arrest. Technical performance was the most common contributing factor: 47% of ASCs and 48% of HORs. Only 7% of allegations relating to technical performance were judged to be a direct result of poor technical performance. The most common anesthesia procedures resulting in ASC claims were injection of anesthesia into a peripheral nerve (34%) and intubation (29%). Obesity was the most common contributing comorbidity in both settings. Mean closed claim value was significantly lower for ASC than HOR claims, averaging US $87,888 versus $107,325.

CONCLUSIONS

Analysis of ASC and HOR claims demonstrates significant differences and several common sources of liability. These include improving strategies for thorough screening, preoperative assessment and risk stratifying of patients, incorporating routine dental and airway assessment and documentation, diagnosing and treating perioperative pain adequately, and improving the efficacy of communication between patients and care providers.

Simulated weight reduction using an anti-gravity treadmill - A pilot study of the impact of weight loss on foot and ankle arthritis

BACKGROUND

Despite a paucity of evidence, obesity is frequently cited as an exacerbator of symptoms in foot and ankle arthritis. The aims of the current study were to determine whether simulated weight loss would improve symptoms in obese patients with foot and ankle arthritis.

METHODS

Patients walked on an "anti-gravity" treadmill allowing simulated weight reduction. Pain was recorded at baseline weight and then compared with pain at simulated normal BMI.

RESULTS

Simulated reduction to BMI 25 caused a significant reduction in pain. Mean pain scores improved from baseline to BMI 25 by 32% (15.9 points, p=0.04). Paired analysis showed a significant improvement in pain scores (p=0.016) from BMI of 30 to 25.

CONCLUSION

Simulated weight loss from high to normal BMI improved arthritic symptoms. This could be used to power future studies to further investigate the effects of weight loss in foot and ankle patients. Level of evidence Level II - repeated measures cohort study.

Obesity, metabolic syndrome, and inflammation: an update for anaesthetists caring for patients with obesity

Our understanding of chronic inflammation in obesity is evolving. Suggested mechanisms include hypoxia of adipose tissue and a subsequent increase in circulating cytokines. It is now known that adipose tissue, far from being an inert tissue, produces and secretes multiple peptides that influence inflammation and metabolism, including substrates of the renin-angiotensin-aldosterone system (RAAS). RAAS blocking antihypertensive medication and cholesterol-lowering agents are now being evaluated for their metabolic and inflammation-modulating effects. Surgery also has pro-inflammatory effects, which may be exacerbated in patients with obesity. This narrative review will summarise the recent literature surrounding obesity, metabolic syndrome, inflammation, and interplay with the RAAS, with evidence-based recommendations for the optimisation of patients with obesity, prior to surgery and anaesthesia.

Obesity and anastomotic leak rates in colorectal cancer: a meta-analysis

PURPOSE

Anastomotic leak (AL) following colorectal cancer resection is associated with considerable morbidity and mortality with an impact on recurrence rates and survival. The impact of obesity on AL rates is debated. This meta-analysis aims to investigate the relationship between obesity and AL.

METHODS

A search was conducted of the PubMed/MEDLINE, and Web of Science databases and included studies were split into Western and Asian groups based on population-specific body mass index (BMI) ranges for obesity. A meta-analysis was performed to assess the impact of obesity on AL rate following colorectal cancer resection.

RESULTS

Two thousand three hundred and four articles were initially screened. Thirty-one studies totaling 32,953 patients were included. Patients with obesity had a statistically significant increase in AL rate in all Western and Asian study groups. However, this increase was only clinically significant in the rectal anastomotic subgroups-Western: 10.8% vs 8.4%, OR 1.57 (1.01-2.44) and Asian: 9.4% vs 7.4%, OR 1.58 (1.07-2.32).

CONCLUSIONS

The findings of this analysis confirm that obesity is a significant risk factor for anastomotic leak, particularly in rectal anastomoses. This effect is thought to be primarily mediated via technical difficulties of surgery although metabolic and immunological factors may also play a role. Obesity in patients undergoing restorative CRC resection should be discussed and considered as part of the pre-operative counselling.

Morbidly obese patient with endometrial cancer treated by bariatric surgery to enable cancer treatment

The case demonstrates the use of bariatric surgery to improve a patient's candidacy for surgical treatment for endometrial cancer (EC). A 50-year-old morbidly obese woman with early-stage EC was initially treated with levonorgestrel-releasing intrauterine system (52 mg) . She had to reduce her body mass index (BMI) to become eligible for definite EC treatment. Using conservative methods, she was unable to lose weight effectively. She then underwent bariatric surgery that reduced her BMI from 71.3 to 54.3 kg/m² She maintained her weight and was eligible for total hysterectomy and bilateral salpingo-oopherectomy. Her procedure was successful and had no complications. She has 6-monthly follow-ups, and the most recent review showed no evidence of recurrence.

Intraoperative Monitoring of the Obese Patient Undergoing Surgery: A Narrative Review

With the increasing prevalence of obesity in the population, anaesthetists must confidently manage both the pathophysiological and technical challenges presented in bariatric and non-bariatric surgery. The intraoperative period represents an important opportunity to optimise and mitigate risk. However, there is little formal guidance on what intraoperative monitoring techniques should be used in this population. This narrative review collates the existing evidence for intraoperative monitoring devices in the obese patients. Although a number of non-invasive blood pressure monitors have been tested, an invasive arterial line remains the most reliable monitor if accurate, continuous monitoring is required. Goal-directed fluid therapy is recommended by clinical practice guidelines, but the methods tested to assess this had guarded applicability to the obese population. Transcutaneous carbon dioxide (CO₂) monitoring may offer additional benefit to standard capnography in this population. Individually titrated positive end expiratory pressure (PEEP) and recruitment manoeuvres improved intraoperative mechanics but yielded no benefit in the immediate postoperative period. Depth of anaesthesia monitoring appears to be beneficial in the perioperative period regarding recovery times and complications. Objective confirmation of reversal of neuromuscular blockade continues to be a central tenet of anaesthesia practice, particularly relevant to this group who have been characterised as an "at risk" extubation group. Where deep neuromuscular blockade is used, continuous neuromuscular blockade is suggested. Both obesity and the intraoperative context represent somewhat unstable search terms, as the clinical implications of the obesity phenotype are not uniform, and the type and urgency of surgery have significant impact on the intraoperative setting. This renders the generation of summary conclusions around what intraoperative monitoring techniques are suitable in this population highly challenging.

Airway events in obese vs. non-obese elective surgical patients: a cross-sectional observational study

Obesity is an increasingly prevalent comorbidity within the UK population. The aim of this study was to determine the proportion of obese patients in an elective surgical population. The second aim was to determine the choice of airway equipment and incidence of airway events in obese vs. non-obese patients. We conducted a cross-sectional observational study over two 24-h periods in March 2018 across 39 hospitals in the greater London area. Data were collected regarding 1874 patients. The incidence of obesity was 32% in the study population compared with 26% in the general UK population (p < 0.0001). Minor airway events were defined as: desaturation to S_p O₂ < 90%; failed mask ventilation; supraglottic airway device problem; aspiration; airway trauma and difficult intubation; or recognised oesophageal intubation. Major airway events were defined as: unrecognised oesophageal intubation; a 'cannot intubate cannot oxygenate' emergency; the need for unplanned front-of-neck airway; cardiac arrest; or unplanned intensive care unit admission due to an airway event. In total, 89 minor and two major airway events were recorded. Obese patients were more likely to experience a minor airway event (RR 2.39, 95%CI 1.60-3.57), the most common being desaturation (S_p O₂ < 90%). The use of a supraglottic airway device in obese vs. non-obese patients was associated with increased airway events (RR 3.46 [1.88-6.40]). Tracheal intubation vs. supraglottic airway device use increased with obesity class but was not associated with a decrease in airway events (RR 0.90 [0.53-1.55]). Our data suggest that obesity is more common in the elective surgical vs. general population and minor airway events are more common in obese vs. non-obese elective patients.

Clinical considerations in providing intravenous sedation with midazolam for obese patients in dentistry

The widespread prevalence of obesity continues to rise. Obesity and dental disease share common risk factors and so the demand for dental care for obese patients is escalating. For some of these patients, there is a corresponding need to be able to provide intravenous sedation safely when it is necessary and appropriate to do so. However, obesity often presents with multiple comorbidities and airway complexities, leading to more challenging management and potentially increased risk. The risk assessment process as well as patient monitoring and management strategies will be explored in this article. By reviewing the literature from dentistry and other medical specialties, we also aim to establish the potential benefit in administering supplemental oxygen and the use of capnography in monitoring this cohort of patients.

Dosing of neuromuscular blocking agents in patients with obesity: A narrative review

There is no consensus on which weight clinicians should use for weight-based dosing of neuromuscular blocking agents (NMBAs), as exemplified by differing or absent recommendations in clinical practice guidelines. The purpose of this paper is to review studies that evaluated various size descriptors for weight-based dosing of succinylcholine and non-depolarising NMBAs, and to provide recommendations for the descriptors of choice for the weight-based dosing of these agents in patients with obesity. All of the studies conducted to date involving depolarising and non-depolarising NMBAs in patients with obesity have assessed single doses or short-term infusions conducted in perioperative settings. Recognising that any final dosing regimen must take into account patient-specific considerations, the available evidence suggests that actual body weight is the size descriptor of choice for weight-based dosing of succinylcholine and that ideal body weight, or an adjusted (or lean) body weight, is the size descriptor of choice for weight-based dosing of non-depolarising NMBAs.

A Prospective Observational Study of High-Dose Intrathecal Diamorphine in Laparoscopic Bariatric Surgery: a Single-Centre Experience

BACKGROUND

Post-operative pain management following laparoscopic bariatric surgery can be challenging. There are concerns regarding the use of opioids. The rate of cardiorespiratory problems following neuraxial opioids is unclear. There is little published data on their use in bariatric surgery. This study aimed to assess technique feasibility, pain outcomes, patient acceptability, and the side effects and complications of a 'high-dose' (1.0 mg) intrathecal diamorphine technique for patients undergoing primary laparoscopic bariatric surgery.

MATERIALS AND METHODS

Fifty patients were included. Eleven patients (22%) had a diagnosis of OSA. All patients had a spinal anaesthetic with 2.0 mL of 0.25% isobaric bupivacaine containing 1.0 mg diamorphine. General anaesthesia followed together with multi-modal analgesia and anti-emesis. Post-operative pain scores, complications, and side effects in the first 24 h post-operative period were documented. Patients were followed up 6 to 8 weeks after discharge.

RESULTS

All patients had a working spinal anaesthetic with thirty-nine insertions (78%) on the first attempt. Pain scores were similar to previously published data where they were found to be superior to a non-spinal analgesic regime. The median 24 h post-operative oral morphine equivalent consumption was 5 mg. Eight patients (16%) required urinary catheterisation. Four patients (8%) complained of pruritus. Eighteen patients (36%) had post-operative nausea or vomiting. Thirty-three patients (66%) responded to the follow-up request. Thirty of the thirty-three patients (91%) stated they would have the spinal anaesthetic again.

CONCLUSION

We have demonstrated that neuraxial blockade is a simple, practical, and feasible technique to adopt. Our case series demonstrated a high level of patient acceptability.

Improving Accurate Blood Pressure Cuff Allocation in Patients with Obesity: A Quality Improvement Initiative

Accurate noninvasive blood pressure (NIBP) measurement requires use of an appropriately sized cuff. We aimed to improve the perioperative allocation of NIBP cuffs in patients with Class II–III obesity. In the baseline evaluation, we measured the mid-arm circumference (MAC) of 40 patients with BMI > 35 kg/m², documenting the corresponding cuff allocated by pre-operative nurses. The intervention consisted of the introduction of cuff allocation based on MAC measurement and augmented NIBP cuff supplies. We completed a re-evaluation and evaluation of the intervention by staff survey, using 5-point Likert scales and free text comments. At baseline, the correct cuff was allocated in 9 of 40 patients (22.5%). During the intervention, education occurred in 54 (69.2%) peri-operative nursing staff. Upon re-evaluation, the correct cuff was allocated in 30 of 40 patients (75.0%), a statistically significant improvement (χ² = 22.1, p < 0.001). Ninety-three of 120 staff surveys were returned (78%). Eleven out of 18 preoperative staff surveyed (61.1%) felt confident measuring the arm and selecting the correct cuff. Six (33%) agreed that taking the arm measurement added a lot of extra work. Equipment shortages, accuracy concerns, and clinical workarounds were reported by staff. Our intervention increased the proportion of correct cuffs allocated, but equipment and practical issues persist with NIBP cuff selection in obese patients.

Intubation outcomes using the aerosol box during the COVID-19 pandemic: A prospective, observational study

BACKGROUND AND AIMS

The aerosol box (AB), an improvised device used during the coronavirus disease (COVID)-19 pandemic, has attracted both interest and controversy. Several simulated studies have examined its protective efficacy as well as intubation efficiency. The aim of this study was to evaluate the practical conduct of intubation using the AB in patients undergoing elective, oncological surgery during the pandemic.

METHODS

This prospective, observational study included adult patients undergoing oncological surgery. Thirteen anaesthesiologists performed 132 intubations using one of three ABs designated as AB 1, AB 2 and AB 3. The primary outcome was the difference in the time to intubation (TTI) between patients with Mallampati score MP I-II (Group 1) and MP III-IV (Group 2). Secondary outcomes included first-pass success rate, fall in peripheral oxygen saturation to < 95%, total number of attempts and failure to intubate using the AB.

RESULTS

The mean TTI was not significantly different in Group 1 and Group 2 (71.02 (61.66) s vs. 101.35 (121.94) s respectively, P = 0.119). Desaturation during intubation was seen in 20 patients (15.1%). First pass success rate was achieved in 109 patients (82.6%). Twenty-one patients (15.9%) needed more than one attempt to intubate and the box had to be removed in 8 patients (6.1%) for facilitating intubation. The Mallampati score did not significantly influence either desaturation or first pass success rate.

CONCLUSION

There was a non-significant increasing TTI trend in patients with a higher MP score with the use of an aerosol box. However, this did not translate to a clinically significant difference in the overall intubation outcomes.

Ultrasound-Guided Erector Spinae Plane Block in Patients Undergoing Laparoscopic Bariatric Surgery: A Prospective Randomized Controlled Trial

BACKGROUND

Bariatric surgery is frequently complicated with considerable postoperative pain. We evaluated the impact of ultrasound-guided erector spinae plane block on perioperative analgesia and pulmonary functions following laparoscopic bariatric surgery.

METHODS

A total of 60 patients aged 18 to 65 years with a body mass index (BMI) of ≥ 40 kg/m² were randomly allocated into two groups. Patients received either bilateral erector spinae plane block using 20 mL bupivacaine 0.25% at the level of the T7 transverse process or bilateral sham block using 20 mL normal saline on each side. Visual analog scale, intraoperative fentanyl consumption, the cumulative 24-hour postoperative morphine consumption, and postoperative pulmonary functions were recorded.

RESULTS

Visual analog scale for the first eight postoperative hours were significantly lower in the erector spinae plane block group than the control group. The median (interquartile range [IQR]) intraoperative fentanyl consumption was higher in the control group (159.5 [112.0 to 177.8] μg) than in the erector spinae plane block group (0.0 [0.0 to 74.5] μg) (P < 0.001). The median (IQR) cumulative 24-hour postoperative morphine consumption was lower in the erector spinae plane block group (8.0 [7.0 to 9.0] mg) than in the control group (21.0 [17.0 to 26.25] mg) (P < 0.001, 95% CI [11.00, 15.00]). Postoperative pulmonary functions were significantly impaired in both groups compared with baseline values without significant difference between both groups.

CONCLUSION

Ultrasound-guided erector spinae plane block provided satisfactory postoperative analgesia following laparoscopic bariatric surgery with decreased analgesic consumption without significant difference in postoperative pulmonary functions compared with the control group.

Exploring new frontiers: Organ transplant anaesthesia or bariatric anaesthesia

Unlike previous years, Anaesthesiology today is a major speciality encompassing many areas of modern medicine. Advent of various surgical sub-specialities resulted into the emergence of anaesthesia sub-specialities, as every group of surgery has specific need. Choosing the best-suited speciality is a complex matter. For that, one needs to have an idea about each one of them. A postgraduate anaesthesiology student does not have adequate exposure to choose the speciality. This article will give an overview of two important sub-specialities i.e., Organ Transplant Anaesthesia and Bariatric Anaesthesia.

The Obese Patient: Facts, Fables, and Best Practices

The prevalence of obesity continues to rise worldwide, and anesthesiologists must be aware of current best practices in the perioperative management of the patient with obesity. Obesity alters anatomy and physiology, which complicates the evaluation and management of obese patients in the perioperative setting. Gastric point-of-care ultrasound (PoCUS) is a noninvasive tool that can be used to assess aspiration risk in the obese patient by evaluating the quantity and quality of gastric contents. An important perioperative goal is adequate end-organ perfusion. Standard noninvasive blood pressure (NIBP) is our best available routine surrogate measurement, but is vulnerable to greater inaccuracy in patients with obesity compared to the nonobese population. Current NIBP methodologies are discussed. Obese patients are at risk for wound and surgical site infections, but few studies conclusively guide the exact dosing of intraoperative prophylactic antibiotics for them. We review evidence for low-molecular-weight heparins and weight-based versus nonweight-based administration of vasoactive medications. Finally, intubation and extubation of the patient with obesity can be complicated, and evidence-based strategies are discussed to mitigate danger during intubation and extubation.

Enhanced Recovery After Bariatric Surgery: Feasibility and Outcomes in a National Bariatric Centre

PURPOSE

This study aimed to assess outcomes of bariatric surgical procedures after the implementation of an enhanced recovery after bariatric surgery protocol in the National Bariatric Centre in Ireland.

MATERIALS AND METHODS

Data on consecutive bariatric procedures performed over a 36-month period was prospectively recorded. ERABS interventions utilized included preoperative counselling, shortened preoperative fasts, specific anaesthetic protocols, early postop mobilization and feeding, and extended post-discharge thromboprophylaxis.

RESULTS

A total of 280 primary bariatric procedures were performed over a 36-month period. The primary procedures were laparoscopic sleeve gastrectomy (57.5%), laparoscopic one anastomosis gastric bypass (33.2%) and laparoscopic Roux-en-Y gastric bypass (9.3%). Mean (SD) age was 48 (± 10) years, mean (SD) preoperative BMI 49.5 (± 9) kg/m² and 68% were female. Median ASA score was 3, and median OSMRS also 3. Over 50% of patients had a diagnosis of hypertension or OSA, and over one-third had a diagnosis of type 2 diabetes mellitus or dyslipidemia. All procedures were completed laparoscopically and 29 patients underwent a simultaneous procedure. The mean (SD) length of stay was 2.3 (± 1.4) days (median 2 days, range 2-47 days). Overall postoperative morbidity rate was 10.0% (n = 29). The 30-day readmission and reoperation rates were 3.6% and 2.5% respectively. There was no mortality recorded in this series.

CONCLUSION

Implementing an ERABS protocol was feasible, safe, associated with low morbidity, no mortality, acceptable LOS and low readmission and reoperation rates. Although patients with obesity have a spectrum of disease-related complications, this should not preclude the use of an ERABS protocol in bariatric surgery.

Severe acute respiratory syndrome coronavirus 2 infection risk during elective peri-operative care: a narrative review

The protection of healthcare workers from the risk of nosocomial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a paramount concern. SARS-CoV-2 is likely to remain endemic and measures to protect healthcare workers against nosocomial infection will need to be maintained. This review aims to inform the assessment and management of the risk of SARS-CoV-2 transmission to healthcare workers involved in elective peri-operative care. In the absence of data specifically related to the risk of SARS-CoV-2 transmission in the peri-operative setting, we explore the evidence-base that exists regarding modes of viral transmission, historical evidence for the risk associated with aerosol-generating procedures and contemporaneous data from the COVID-19 pandemic. We identify a significant lack of data regarding the risk of transmission in the management of elective surgical patients, highlighting the urgent need for further research.

A Randomized Comparison of Non-Channeled GlidescopeTM Titanium Versus Channeled KingVisionTM Videolaryngoscope for Orotracheal Intubation in Obese Patients with BMI > 35 kg·m-2

Videolaryngoscopes may improve intubating conditions in obese patients. A total of 110 patients with a body mass index > 35 kg∙m-2 were prospectively randomized to tracheal intubation using non-channeled Glidescope Titanium or channeled King Vision videolaryngoscope. The primary outcome was the time to tracheal intubation. Secondary outcomes included: total success rate, number of attempts, the quality of visualization, peri-procedural and post-proceduralcomplications. Time to the first effective breath was shorter with the King Vision (median; 95% CI)-36; 34-39 s vs. 42; 40-50 in the Glidescope group (p = 0.007). The total success rate was higher in the Glidescope group-100% vs. 89.1% (p = 0.03). There was a higher incidence of moderate and difficult laryngoscopy in the King Vision group. No difference was recorded in first attempt success rates, total number of attempts, use of additional maneuvers, intraoperative trauma, or any significant decrease in SpO2 during intubation. No serious complications were noted and the incidence of postoperative complaints was without difference. Although tracheal intubation with King Vision showed shorter time to the first breath, total success was higher in the Glidescope group, and all but one patients where intubation failed with the KingVision were subsequently intubated with the Glidescope.

Effect of Intraoperative Goal-Directed Fluid Management on Tissue Oxygen Tension in Obese Patients: a Randomized Controlled Trial

Background

Perioperative subcutaneous tissue oxygen tension (PsqO₂) is substantially reduced in obese surgical patients. Goal-directed fluid therapy optimizes cardiac performance and thus tissue perfusion and oxygen delivery. We therefore tested the hypothesis that intra- and postoperative PsqO₂ is significantly reduced in obese patients undergoing standard fluid management compared to goal-directed fluid administration.

Methods

We randomly assigned 60 obese patients (BMI ≥ 30 kg/m²) undergoing laparoscopic bariatric surgery to receive either esophageal Doppler-guided goal-directed fluid management or conventional fluid treatment. Our primary outcome parameter was intra- and postoperative PsqO₂ measured with a polarographic electrode in the subcutaneous tissue of the upper arm. A random effects linear regression model was used to analyze the effect of intervention.

Results

Overall, mean (± SD) PsqO₂ was significantly higher in obese patients receiving goal-directed therapy compared to conventional fluid therapy (65.8 ± 28.0 mmHg vs. 53.7 ± 21.7, respectively; repeated measures design adjusted difference: 13.0 mmHg [95% CI 2.3 to 23.7; p = 0.017]). No effect was seen intraoperatively (69.6 ± 27.9 mmHg vs. 61.4 ± 28.8, difference: 9.7 mmHg [95% CI -3.8 to 23.2; p = 0.160]); however, goal-directed fluid management improved PsqO₂ in the early postoperative phase (63.1 ± 27.9 mmHg vs. 48.4 ± 12.5, difference: 14.5 mmHg [95% CI 4.1 to 24.9; p = 0.006]). Intraoperative fluid requirements did not differ between the two groups.

Conclusions

Goal-directed fluid therapy improved subcutaneous tissue oxygenation in obese patients. This effect was more pronounced in the early postoperative period.

Clinical Trial Number and Registry

The study was registered at ClinicalTrials.gov (NCT 01052519).

Use of Processed Electroencephalography in the Clinical Setting

Purpose of Review

Processed electroencephalography (pEEG) is widely used in clinical practice. Few clinicians utilize the full potential of these devices. This brief review will address the improvements in patient management available from the utilization of all pEEG data.

Recent Findings

Anesthesiologists easily learn to recognize raw pEEG patterns that are consistent with an appropriate level of hypnotic effect. Power distribution within the waveform can be displayed in a visual format that identifies signatures of the principal anesthetic hypnotics. Opinion on the benefit of pEEG data in the mitigation of postoperative neurological impairment remains divided.

Summary

Looking beyond the index number can aid clinical decision making and improve confidence in the benefits of this monitoring modality.

Postoperative outcomes of ventral hernia repair in veterans

BACKGROUND

Ventral hernia repair is a common procedure with reported 15% to 37% morbidity and 0.3% to 1.4% mortality rates. This study examines the 30-day morbidity and mortality of open and laparoscopic ventral hernia repair in veterans, along with the impact of body mass index on these outcomes.

METHODS

The Veterans Affairs Surgical Quality Improvement Program was queried for all ventral hernia repairs during the period 2008 to 2015. In this retrospective analysis, we compared outcomes of open ventral hernia repair versus laparoscopic ventral hernia repair and among different body mass index classes.

RESULTS

A total of 19,883 patients were identified (92.6% male, mean age 59.7, 53.1% obese, and 71.6% with American Society of Anesthesiologists class ≥III). There were 95 (0.5%) mortalities, and complications occurred in 1,289 (6.5%) patients. Open ventral hernia repair was performed in 60.2%; 14.5% were recurrent, and 3.3% were performed as an emergency operation. When compared with open ventral hernia repair, the laparoscopic ventral hernia repair group had higher mean body mass index, less patients with American Society of Anesthesiologists class ≥III, fewer emergency operations, longer operative time, less complications, decreased mortality, and shorter duration of stay. Body mass index 35.00 to 49.99 was predictive of overall complications in the open ventral hernia repair group.

CONCLUSION

Ventral hernia repair can be performed in the veteran population with outcomes comparable to those in the private sector. Morbid obesity has a negative impact on ventral hernia repair outcomes that is most prominent following open surgery. Laparoscopic ventral hernia repair may offer superior outcomes when compared to open ventral hernia repair and may be considered.

A Comparative Evaluation of the Effect of Prone Positioning Methods on Blood Loss and Intra-Abdominal Pressure in Obese Patients Undergoing Spinal Surgery

Background Improper prone positioning of obese patients for spine surgery can increase the intra-abdominal pressure (IAP), resulting in increased bleeding from epidural venous plexus. The choice of prone positioning frame can be an important determinant of the IAP.

Materials and Methods This prospective, randomized study was performed on obese patients (body mass index ≥ 30) scheduled for lumbar laminectomy. After administration of general anesthesia, patients were positioned prone either on Wilson’s frame (group W), or on horizontal bolsters (group H). IAP was recorded at three intervals: (1) in supine position, (2) 10 minutes after prone positioning, and (3) in prone position at the end of surgery. Intraoperative blood loss was measured quantitatively and assessed subjectively by the surgeon.

Results A total of 60 patients were enrolled with 30 patients in each group. IAP in supine position was similar in both groups. However, IAP 10 minutes after prone positioning was significantly higher at 11.44 ± 1.61 mm Hg in group W as compared to 9.56 ± 1.92 mm Hg in group H (p = 0.001). Similarly, IAP of 12.24 ± 1.45 mm Hg in group W, measured on completion of surgery was significantly higher than 9.96 ± 2.35 mm Hg in group H (p = 0.001). Mean total blood loss of 440.40 ± 176.98 mL in group W was significantly higher than 317.20 ± 91.04 mL in group H (p = 0.003).

Conclusion Obese patients positioned prone on Wilson’s frame had significantly higher IAP and blood loss compared to patients positioned on horizontal bolsters.

Preoperative communication between anaesthetists and patients with obesity regarding perioperative risks and weight management: a structured narrative review

BACKGROUND

Individuals with obesity frequently present for anaesthesia and surgery. Good communication during the preoperative consultation can optimise the provision of relevant health information and guide improvement of health status preoperatively.

METHODS

We planned a systematic literature review to assess existing guidelines and evidence of effectiveness for how anaesthetists should communicate with patients who have obesity in the preoperative period about perioperative risks and weight management. Database searches used keywords related to perioperative weight loss conversations. We found no papers that directly addressed our aim. The literature identified as most relevant was analysed in the form of a narrative review.

RESULTS

The majority of suggestions for weight loss conversations came from primary care. Four primary themes potentially relevant to anaesthetists were identified: barriers to such conversations, communication tools, language and communication and specific recommendations. Identified barriers included lack of skills, training, poor remuneration, pessimism and time constraints for clinicians. Established discussion tools including the '5A's' approach (Assess, Advise, Agree, Assist, Arrange) and motivational interviewing may hold promise to improve preoperative conversations. The papers highlighted a need for empathetic language, including use of patient-specific language where possible.

CONCLUSIONS

There are currently no published guidelines for how anaesthetists could most effectively discuss weight in the perioperative period with patients who have obesity. Much of the literature for obesity communication is based on the primary care setting. The perioperative period may represent an increased time of receptiveness for patients. Guidelines for discussions about weight management and associated perioperative risk are suggested.

Robotic versus laparoscopic hysterectomy in morbidly obese women for endometrial cancer

Surgery is the mainstay treatment for endometrial cancer and complex atypical endometrial hyperplasia. These conditions are more common in the obese women and as such these patients pose additional risks and challenges to surgery. Laparoscopic hysterectomy (LH) is preferred over open surgery in obese patients as it reduces surgical morbidity. However, more recently, robotic-assisted hysterectomy (RH) has been used in morbidly obese patients to overcome the limitations of conventional laparoscopy. To compare the surgical outcomes of morbidly obese patients undergoing LH or RH for endometrial cancer or complex atypical hyperplasia. A retrospective analysis of morbidly obese patients (BMI > 40 kg/m²) who underwent LH or RH for endometrial cancer or complex atypical hyperplasia at the Chris O'Brien Lifehouse Gynaecological Oncology Unit from 2015 to 2019 was performed. Data was collected from the prospectively maintained gynaecology oncology database and descriptive analysis was performed. 33 (51.6%) underwent LH and 31 (48.4%) had RH. More LHs were performed 2015-2017 period, whereas there were more RHs performed in 2018-2019 period (p = 0.01). The difference between theatre time use and operating time for LH surgery compared to RH was significantly shorter (45.7 for LH versus 61.9 min for RH, p = 0.009). RH was performed more commonly when BMI was > 50 kg/m² (p = 0.02). There has been an increase in the use of RH in morbidly obese patients, particularly for women with a BMI > 50 kg/m².

Assessment of Kidney Function in Patients With Extreme Obesity: A Narrative Review

Objectives:

To discuss the evidence and caveats associated with estimated and measured creatinine clearance (eClCr and mClCr) and glomerular filtration rate (eGFR and mGFR) assessments of kidney function in patients with more extreme forms of obesity.

Data Sources:

PubMed (1976 to mid-May 2020) was used, with bibliographies of retrieved articles searched for additional articles.

Study Selection and Data Extraction:

Articles using gold standard mGFR to evaluate eClCr, mClCr, and eGFR assessments of kidney function in patients with more extreme forms of obesity were included.

Data Synthesis:

The overestimation of GFR by mClCr is well established, but mClCr is an alternative to mGFR assessments for determining medication dosing in patients with extremes of body size or muscle mass, or in patients receiving narrow therapeutic index medications when eGFR is likely to be inaccurate. The vast majority of studies comparing eGFR assessments with gold standard indicators of kidney function were attempts to validate eGFR equations for diagnosing and staging chronic kidney disease (CKD).

Relevance to Patient Care and Clinical Practice:

For dosing medications in patients with stable kidney function and extreme obesity, a deindexed 4-variable Modification of Diet in Renal Disease or CKD Epidemiology Collaboration equation is an alternative to Cockcroft-Gault. Consistent use of the same equation by provider and between providers within any given setting is of paramount importance.

Conclusions:

In patients with extreme obesity and stable kidney function, eClCr or eGFR using deindexed values provides estimates of function for dosing adjustments of medications with elimination by the kidneys, but more research is needed with respect to the best size descriptor to use with estimating equations.

Effect of intra-operative intravenous lidocaine on opioid consumption after bariatric surgery: a prospective, randomised, blinded, placebo-controlled study

Peri-operative lidocaine infusion warrants investigation in bariatric surgery because obese patients present different physiological and pharmacological risks. This single-centre, prospective, randomised double-blind placebo-controlled study enrolled obese patients scheduled for laparoscopic bariatric surgery using an enhanced recovery protocol. Patients received either lidocaine (bolus of 1.5 mg.kg^-1 , then a continuous infusion of 2 mg.kg^-1 .h^-1 until the end of the surgery, then 1 mg.kg^-1 .h^-1 for 1 h in the recovery area) or identical volumes and rates of 0.9% saline. The primary outcome was the consumption of the equivalent of oxycodone consumption over the first 3 postoperative days. Secondary outcomes were: postoperative pain; incidence of nausea and vomiting; bowel function recovery; and lengths of stay in the recovery area and in hospital. Plasma concentrations of lidocaine were measured. On the 178 patients recruited, data were analysed from 176. The median (IQR [range]) equivalent intravenous oxycodone consumption was 3.3 mg (0.0-6.0 [0.0-14.5]) and 5.0 mg (3.3-7.0 [3.3-20.0]) in the lidocaine and saline groups, respectively (difference between medians (95%CI): 1.7 (0.6-3.4) mg; p = 0.004). Length of stay in the recovery area, postoperative pain, nausea and vomiting, day of recovery of bowel function, and length of stay in hospital were not different between groups. Mean (SD) lidocaine plasma concentrations were 2.44 (0.70) µg.ml^-1 and 1.77 (0.51) µg.ml^-1 at the end of surgery and 1 hour after the end of infusion, respectively. Lidocaine infusion during bariatric surgery resulted in a clinically non-relevant difference in postoperative oxycodone consumption.

Intraoperative lidocaine infusion and 24-hour postoperative opioid consumption in obese patients undergoing laparoscopic bariatric surgery

BACKGROUND

Bariatric surgery is the most effective long-term treatment for obesity. Opioid-sparing anesthesia and multimodal analgesia such as lidocaine infusion have been recommended in these patients to reduce opioid-related complications. However, evidence supporting its use for bariatric surgery population is limited.

OBJECTIVE

To investigate whether intraoperative lidocaine infusion is associated with decreasing opioid consumption in laparoscopic bariatric surgery.

SETTING

A university hospital, California, USA.

METHODS

In this retrospective cohort study, outcomes among consecutive obese patients undergoing laparoscopic bariatric surgery between January 2016 to December 2018 were evaluated to determine the impact of adjunctive intraoperative lidocaine infusion on 24-hour postoperative opioid consumption. Secondary outcomes, including opioid consumption during hospitalization, length of stay, and postoperative complications were determined. Post hoc analyses were performed exploring possible dose effects and drug-drug interactions. Univariable and multivariable analyses were performed to identify factors associated with opioid consumption.

RESULTS

Among 345 patients, 54 (15.7%) received intraoperative lidocaine infusion (L+) whereas 291 (84.3%) did not receive intraoperative lidocaine infusion (L-). Both L+ and L- groups shared similar demographic characteristics. The 24-hour postoperative opioid consumption was 17.6% lower in L+ (95% confidence interval -28.4 to -5.2, P = .007), but nonsignificantly lower in the multivariate model (12.8%, 95% confidence interval -24.4 to .5, P = .06). Opioid consumption during hospitalization, length of stay, and other clinically significant outcomes did not differ. However, subgroup analysis restricted to opioid-naïve patients indicated significantly reduced opioid consumption in the L+ group. Post hoc analysis suggested interaction between lidocaine and ketamine in decreasing 24-hour postoperative opioid consumption.

CONCLUSIONS

Intraoperative lidocaine infusion was not significantly associated with decreasing 24-hour postoperative opioid consumption in obese patients undergoing laparoscopic bariatric surgery.

Drug dosing in the critically ill obese patient-a focus on sedation, analgesia, and delirium

Practice guidelines provide clear evidence-based recommendations for the use of drug therapy to manage pain, agitation, and delirium associated with critical illness. Dosing recommendations however are often based on strategies used in patients with normal body habitus. Recommendations specific to critically ill patients with extreme obesity are lacking. Nonetheless, clinicians must craft dosing regimens for this population. This paper is intended to help clinicians design initial dosing regimens for medications commonly used in the management of pain, agitation, and delirium in critically ill patients with extreme obesity. A detailed literature search was conducted with an emphasis on obesity, pharmacokinetics, and dosing. Relevant manuscripts were reviewed and strategies for dosing are provided.