Anaesthesia for the obese patient

Association Between Body Mass Index and Clinical Outcomes of Gender-Affirming Masculinizing Chest Reconstruction

INTRODUCTION

Body mass index (BMI) is often used in surgical settings to determine patients' risk of complications. In the context of gender-affirming care, BMI requirements for surgery can limit access to necessary care for larger-bodied people. There is a critical need to understand the association between BMI and postoperative outcomes for this population.

METHODS

A retrospective chart review was conducted using the first 250 consecutive gender-affirming masculinizing chest reconstructions performed between 2017 and 2021 at a large academic medical institution. The relationships between BMI, preoperative factors, and common postsurgical outcomes were assessed.

RESULTS

Average BMI at surgery was 27.5 ± 6.7 kg/m2. Increases in BMI were associated with longer drain stays, larger volume of tissue resected, higher likelihood of nipple grafts, and lower likelihood of periareolar surgery (all P < 0.0001). Simple logistic regression revealed that BMI increases were significantly related to the likelihood of experiencing dog ears in the intermediate term (P = 0.002). Multivariate logistic regression adjusted for common covariates (age, ethnicity, smoking status, asthma, autoimmune disorders, cardiovascular conditions, and mental health disorders) did not reveal any significant relationships between BMI and the likelihood of experiencing complications at any study point.

CONCLUSIONS

Masculinizing chest reconstruction is safe and satisfactory for young adult patients across the range of BMI, with significant differences in outcomes found only for esthetic complications (i.e., dog ears). Surgeons should inform patients with higher BMIs about what outcomes to expect but higher BMI should not preclude surgery access.

The Effect of Increased Intra-Abdominal Pressure on Hemodynamics in Laparoscopic Cholecystectomy-The Experience of a Single Centre

Laparoscopic cholecystectomy is characterized by reduced postoperative pain, shorter hospital stays, rapid return to preoperative physical activity, and less psychological impact on the patient. During laparoscopic cholecystectomy, the intra-abdominal insufflation of carbon dioxide with secondary increase in intra-abdominal pressure can cause important hemodynamic consequences, like decreased cardiac output and blood pressure, as well as compensatory increase in heart rate. The purpose of this study is to evaluate changes in cardiovascular parameters during general anesthesia in patients undergoing laparoscopic cholecystectomy. Retrospective data from 342 patients with cholecystectomy for cholelithiasis performed at Railway Hospital Galati, Romania, were reviewed. All patients received the same intraoperative anesthetics. Female patients were 85.7% (n = 293). More than half of the patients, 53.51% (n = 183), were 40-59 years old, and only 16.37% (n = 56) were under 40 years old. Patients with a normal body mass index (BMI) represented 45.6% (n = 156), 33.3% (n = 114) were underweight, and 12% (n = 42) had grade 1 obesity (BMI 25-29.9 kg/m2). The minimum intraoperative blood pressure correlated with patient gender (p 0.015 < 0.005), with men having a higher blood pressure than women (p 0.006 < 0.05), and for BMI, a higher BMI was associated with elevated blood pressure (p 0.025 < 0.05). Older age correlated with an increased maximum intraoperative blood pressure (p < 0.001 < 0.05) and with maximum intraoperative heart rate (p 0.015 < 0.05). Patients undergoing laparoscopic cholecystectomy experienced significant hemodynamic changes with pneumoperitoneum, but this type of surgical intervention was safe for patients regardless of their age.

The Effect of Recruitment Maneuver on Static Lung Compliance in Patients Undergoing General Anesthesia for Laparoscopic Cholecystectomy: A Single-Centre Prospective Clinical Intervention Study

Background and Objectives: The aim of this study was to examine whether the use of an alveolar recruitment maneuver (RM) leads to a significant increase in static lung compliance (Cstat) and an improvement in gas exchange in patients undergoing laparoscopic cholecystectomy. Material and Methods: A clinical prospective intervention study was conducted. Patients were divided into two groups according to their body mass index (BMI): normal-weight (group I) and pre-obese and obese grade I (group II). Lung mechanics were monitored (Cstat, dynamic compliance-Cdin, peak pressure-Ppeak, plateau pressure-Pplat, driving pressure-DP) alongside gas exchange, and hemodynamic changes (heart rate-HR, mean arterial pressure-MAP) at six time points: T1 (induction of anesthesia), T2 (formation of pneumoperitoneum), T3 (RM with a PEEP of 5 cm H2O), T4 (RM with a PEEP of 7 cm H2O), T5 (desufflation), and T6 (RM at the end). The RM was performed by increasing the peak pressure by +5 cm of H2O at an equal inspiration-to-expiration ratio (I/E = 1:1) and applying a PEEP of 5 and 7 cm of H2O. Results: Out of 96 patients, 33 belonged to group I and 63 to group II. An increase in Cstat values occurred after all three RMs. At each time point, the Cstat value was measured higher in group I than in group II. A higher increase in Cstat was observed in group II after the second and third RM. Cstat values were higher at the end of the surgical procedure compared to values after the induction of anesthesia. The RM led to a significant increase in PaO2 in both groups without changes in HR or MAP. Conclusions: During laparoscopic cholecystectomy, the application of RM leads to a significant increase in Cstat and an improvement in gas exchange. The prevention of atelectasis during anesthesia should be initiated immediately after the induction of anesthesia, using protective mechanical ventilation and RM.

Impact of obesity on outcomes after surgical stabilization of multiple rib fractures: Evidence from the US nationwide inpatient sample

BACKGROUND

Obesity is a global health issue with increasing prevalence. Surgical procedures, such as surgical stabilization of rib fractures (SSRF), may be affected by obesity-related complications. The objective of the study is to investigate the effects of obesity on SSRF outcomes in multiple rib fractures.

METHODS

This retrospective study analyzed data from adults aged ≥ 20 years in the Nationwide Inpatient Sample (NIS) database diagnosed with multiple rib fractures who underwent SSRF between 2005 and 2018. It investigated the relationship between obesity and in-patient outcomes, such as discharge status, length of stay (LOS), in-hospital mortality, hospital costs, and adverse events using logistic and linear regression analyses.

RESULTS

Analysis of data from 1,754 patients (morbidly obese: 87; obese: 106; normal weight: 1,561) revealed that morbid obesity was associated with longer LOS (aBeta = 0.07, 95% CI: 0.06, 0.07), higher hospital costs (aBeta = 47.35, 95% CI: 38.55, 56.14), increased risks of adverse events (aOR = 1.63, 95% CI: 1.02, 2.61), hemorrhage/need for transfusion (aOR = 1.77, 95% CI: 1.12, 2.79) and mechanical ventilation ≥ 96 hours (aOR = 2.14, 95% CI: 1.28, 3.58) compared to normal weight patients. Among patients with flail chest, morbid obesity was significantly associated with tracheostomy (aOR = 2.13, 95% CI: 1.05, 4.32), ARDS/respiratory failure (aOR = 2.01, 95% CI: 1.09, 3.70), and mechanical ventilation ≥ 96 hours (aOR = 2.80, 95% CI: 1.47, 5.32). In contrast, morbid obesity had no significant associations with these adverse respiratory outcomes among patients without a flail chest (p > 0.05).

CONCLUSIONS

Morbid obesity is associated with adverse outcomes following SSRF for multiple rib fractures, especially for flail chest patients.

Influence of semaglutide use on the presence of residual gastric solids on gastric ultrasound: a prospective observational study in volunteers without obesity recently started on semaglutide

PURPOSE

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) have become increasingly popular as both diabetic and weight loss therapies. One effect of this class of medication is delayed gastric emptying, which may impact the risk of aspiration during anesthesia delivery.

METHODS

In this prospective study, we used gastric ultrasound to evaluate the presence of solid gastric contents in both supine and lateral positions after an eight-hour fast in those taking GLP-1RA compared with controls. Participants underwent a second ultrasound evaluation two hours later after drinking 12 fluid ounces of water (approximately 350 mL).

RESULTS

Twenty adults voluntarily enrolled, giving a total of ten participants in each group. In the supine position, 70% of semaglutide participants and 10% of control participants had solids present on gastric ultrasound (risk ratio [RR], 3.50; 95% confidence interval [CI], 1.26 to 9.65; P = 0.02.) In the lateral position, 90% of semaglutide participants and 20% of control participants had solids identified on gastric ultrasound (RR, 7.36; 95% CI, 1.13 to 47.7; P = 0.005). Two hours after drinking clear liquids, the two groups did not differ in the lateral position, but in the supine position, 90% of control group participants were rated as empty compared with only 30% of semaglutide group participants (P = 0.02).

CONCLUSIONS

This study provides preliminary evidence that GLP-1RAs may affect gastric emptying and residual gastric contents following an overnight fast and two hours after clear liquids, which may have implications for aspiration risk during anesthetic care.

Anaesthetic nurse specialist role in perioperative anaesthetic management of patients who are morbidly obese

This integrative literature review examined the role of an anaesthetic nurse specialist (ANS) in the perioperative anaesthetic nursing management of morbidly obese patients associated with elective orthopaedic surgery. The responsibility of the ANS is to provide high-quality perioperative anaesthetic care to ensure patient safety. Morbid obesity is increasing globally, with significant implications for healthcare delivery, care and treatment, including perioperative care. The Association of Anaesthetists of Great Britain and Ireland emphasises that the perioperative management of these patients presents significant organisational and practical issues. However, there are limited data or guidelines on whether surgeons, anaesthetists and nurses routinely take special precautions in managing morbidly obesity patients undergoing elective orthopaedic operative procedures. The authors carried out a search of databases, followed by an integrated literature review and synthesis of 11 studies. The main findings revealed significant clinical challenges and resource requirements for perioperative anaesthetic management of this patient group. Recommendations are made to prepare for and manage these surgical patients, from preoperative assessment to postoperative care.

Obesity and menstrual disorders

Obesity is a growing public health concern and is associated with a range of menstrual disorders, including heavy menstrual bleeding, oligomenorrhea, dysmenorrhea, and endometrial pathology. Investigations may be more logistically challenging in those in the population with obesity, and because of the heightened risk of endometrial malignancy, there should be a low threshold for biopsy to exclude endometrial hyperplasia. Although treatment modalities for women with obesity are broadly similar to those with a normal BMI, additional consideration must be given to the risks associated with estrogen in obesity. Outpatient management of heavy menstrual bleeding is a developing field and outpatient treatment modalities are preferable in the population with obesity to avoid the morbidity associated with anesthetics.

Comparing nasopharyngeal apnoeic oxygenation at 18 l/min to preoxygenation alone in obese patients - A randomised controlled study

STUDY OBJECTIVE

Investigate a low-cost, nasopharyngeal apnoeic oxygenation technique, establish its efficacy, and compare it to preoxygenation only in an obese population. The study's hypothesis was that nasopharyngeal apnoeic oxygenation at 18 l.min^-1 would significantly prolong safe apnoea time compared to preoxygenation alone.

DESIGN

Randomised controlled study.

SETTING

Theatre complex of a resource constrained hospital.

PATIENTS

30 adult, obese (BMI ≥ 35 kg.m^-2) patients presenting for elective surgery. Patients with limiting cardio-respiratory disease, suspected difficult airway, risk of aspiration, and that were pregnant, were excluded. Patients were allocated by block randomisation in a 1:2 ratio to a preoxygenation-only (No-AO) and an intervention group (NPA-O₂).

INTERVENTIONS

All patients were preoxygenated to an Et-O2 > 80%, followed by a standardised induction. The intervention group received oxygen at 18 l.min^-1 via the nasopharyngeal catheter intervention. The desaturation process was documented until an SpO₂ of 92% or 600 s was reached.

MEASUREMENTS

Baseline demographic and clinical characteristics were collected. The primary outcome was safe apnoea time, defined as the time taken to desaturate to an SpO₂ of 92%. Secondary outcomes were rate of carbon dioxide accumulation and factors affecting the risk of desaturation.

MAIN RESULTS

The study was conducted in a morbidly obese population (NoAO = 41,1 kg.m^-2; NPA-O₂ = 42,5 kg.m^-2). The risk of desaturation was signifantly lower in the intervention group (Hazzard Ratio = 0,072, 95% CI[0,019-0,283]) (Log-Rank test, p < 0.001). The median safe apnoea time was significantly longer in the intervention group (NoAO = 262 s [IQR 190-316]; NPA-O₂ = 600 s [IQR 600-600]) (Mann-Whitney-U test, p < 0.001). The mean rate of CO₂ accumalation was significantly slower in the intervention group (NoAO = 0,47 ± 0,14 kPa.min^-1; NPA-O₂ = 0,3 ± 0,09 kPa.min^-1) (t-test, p = 0.003). There were no statistically significant risk factors associated with an increased risk of desaturation found.

CONCLUSIONS

Nasopharyngeal apnoeic oxygenation at 18 l/min prolongs safe apnoea time, compared to preoxygenation alone, and reduces the risk of desaturation in morbidly obese patients.

CLINICAL TRIAL REGISTRATION

PACTR202202665252087; WC/202004/007.

Sensitivity of a preanaesthesia screening and triage tool in identifying high-risk patients attending the preanaesthesia assessment clinic in a tertiary referral hospital in Sub-Saharan Africa: a diagnostic accuracy study

OBJECTIVES

The use of preoperative triage questionnaires is an innovative way to mitigate the shortage of anaesthesiologists and to identify and refer high-risk patients early for evaluation. This study evaluates the diagnostic accuracy of one such questionnaire in identifying high-risk patients in a Sub-Saharan population.

DESIGN

Diagnostic accuracy study SETTING: The study was conducted in a preanaesthesia assessment clinic in a tertiary referral hospital in Sub-Saharan Africa.

PARTICIPANTS

The study had a sample size of 128, including all patients above the age of 18 scheduled for elective surgery under any modality of anaesthesia other than local anaesthesia presenting to the preanaesthesia clinic. Patients scheduled for cardiac and major non-cardiac surgery and those non-literate in English were excluded.

OUTCOME MEASURES

The sensitivity of the preanaesthesia risk assessment tool (PRAT) was the primary outcome measure. Other outcome measures were specificity, positive predictive value and negative predictive value.

RESULTS

Majority of patients were young and women with a mean age of 36 referred for obstetric and gynaecological procedures. The sensitivity of the PRAT in identifying high-risk patients was at 90.6% with 95% CI (76.9 to 98.2) in this current study while the specificity, negative predictive value (NPV) and positive predictive value (PPV) were 37.5% with 95% CI (24.0 to 43.7), 92.3% with 95% CI (77.7 to 97.0) and 32.6% with 95% CI (29.6 to 37.3) respectively.

CONCLUSION

The PRAT has a high sensitivity and may be used as a screening tool in identifying high risk patients to refer to the anaesthesiologist early before surgery. Adjusting the high risk criteria to fit the anaesthesiologists' assessments may improve the specificity of the tool.

High-Flow Nasal Cannula for Apneic Oxygenation in Obese Patients for Elective Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Obese patients desaturate rapidly during the apneic period after induction of anesthesia for elective surgery. Administration of oxygen using high-flow nasal cannulae (HFNCs) may prevent desaturation in nonobese patients compared to facemask (FM) preoxygenation. The aim of this meta-analysis was to compare the effectiveness of HFNC to FM preoxygenation techniques in reducing preintubation desaturation in obese patients undergoing elective surgery.

METHODS

This study protocol was registered on PROSPERO (CRD42022309391). Adult studies that compared HFNC and FM preoxygenation in obese patients requiring general anesthesia for elective surgery were included. The primary outcome was desaturation resulting in oxygen saturation of <92% from induction of anesthesia until intubation. Secondary outcomes included the lowest arterial oxygen content before intubation expressed in mm Hg, safe apnea time expressed in seconds, the lowest oxygen saturation before intubation expressed as a percentage, patient-reported discomfort, the need for rescue ventilation, and the incidence of aspiration of gastric contents during intubation. Risk of bias was assessed using the Cochrane Collaboration tool. Certainty was assessed following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Six studies including 351 participants were eligible for analysis. There was no difference in odds of oxygen desaturation <92% between HFNC and FM (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.15-1.63; P = .24). The HFNC group had a significantly longer safe apnea time (mean difference [MD], -124.20 with 95% CI, -200.47 to -47.93; P = .001). There was no difference between HFNC and FM in the lowest arterial oxygen content (MD, -23.90; 95% CI, -88.64 to 40.85; P = .47) and the lowest peripheral oxygenation saturation (MD, -0.47 with 95% CI, -5.07 to 4.12; P = .84). HFNC had a lower odd of discomfort than FM (OR, 0.13; 95% CI, 0.03-0.52; P = .004). There was no difference in the odds of aspiration of gastric contents between HFNC and FM (OR, 0.33; 95% CI, 0.01-8.21; P = .50). The risk of bias for our primary and secondary outcomes was low. The GRADE assessment for our primary outcome indicated a low level of certainty. For secondary outcomes, the GRADE assessment indicated a very low certainty for all outcomes except for patient discomfort, which was indicated as a moderate level of certainty.

CONCLUSIONS

There may be no difference between HFNC and FM preoxygenation in preventing oxygen desaturation <92% or the lowest oxygen saturation before intubation. Preparation remains important to prevent and manage desaturation during induction of obese patients.

Colorectal Cancer and the Obese Patient: A Call for Guidelines

The link between obesity and colorectal cancer has been well established. The worldwide rise in obesity rates in the past 40 years means that we are dealing with increasing numbers of obese patients with colorectal cancer. We aimed to review the existing guidelines and make recommendations specific to this group of patients. Upon comparing the current NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines ®), the guidelines from the European Society of Medical Oncology (ESMO) and the guidelines of the Japanese Society for Cancer of the Colon and Rectum (JSCCR), we observed that these did not take into consideration the needs of obese patients. We proceeded to make specific recommendations with regards to the diagnostic work-up, surgical pathways, minimally invasive technique, perioperative treatment, post-operative surveillance, and management of metastatic disease in this group of patients. Our review highlights the need for modification of the existing guidelines to account for the needs of this patient cohort. A multidisciplinary approach, including principles used by bariatric surgeons, should be the way forward to reach consensus in the management of this group of patients.

Advanced endoscopic gastrointestinal techniques for the bariatric patient: implications for the anesthesia provider

PURPOSE OF REVIEW

The incidence of obesity and the use of endoscopy have risen concurrently throughout the 21st century. Bariatric patients may present to the endoscopy suite for primary treatments as well as preoperatively and postoperatively from bariatric surgery. However, over the past 10 years, endoscopic bariatric and metabolic therapies (EBMTs) have emerged as viable alternatives to more invasive surgical approaches for weight loss.

RECENT FINDINGS

The United States Food and Drug Administration (FDA) has approved several different gastric EBMTs including aspiration therapy, intragastric balloons, and endoscopic suturing. Other small intestine EBMTs including duodenal mucosal resurfacing, endoluminal magnetic partial jejunal diversion, and Duodenal-Jejunal Bypass Liner are not yet FDA approved, but are actively being investigated.

SUMMARY

Obesity causes anatomic and physiologic changes to every aspect of the human body. All EBMTs have specific nuances with important implications for the anesthesiologist. By considering both patient and procedural factors, the anesthesiologist will be able to perform a safe and effective anesthetic.