Obese patients: respiratory complications in the post-anesthesia care unit

Factors Associated With Prolonged-Stay Patients Within the Post-anesthesia Care Unit: A Cohort Retrospective Study

BACKGROUND

The post-anesthesia care unit (PACU) plays a crucial role in providing specialized care to postoperative patients. However, a subset of these patients experiences complications that result in a prolonged stay of 90 minutes or more in the PACU. This not only impacts the patient's quality of life but also disrupts hospital workflow, as it might cause postoperative pain, nausea, or vomiting. It is essential to identify the factors contributing to this prolonged length of stay (LOS) and explore strategies for its prevention and management.  Methods: We conducted a retrospective cohort study of postoperative patients between 2020 and 2021. We included patients who had a prolonged stay, excluding cardiac patients, patients who had a planned prolonged stay, and patients waiting for an intensive care unit bed. We used a non-probability consecutive sampling technique. Data were obtained from the BestCare System, the hospital's information system, using a data collection sheet.

RESULTS

A total of 15,170 patients underwent surgical procedures during the study period, out of which only 181 (1.19%) experienced a prolonged PACU stay. Pain and altered mental status were strongly associated with a prolonged PACU stay (P = 0.035 and P = 0.0009, respectively). However, there was no significant association between overall comorbidities and prolonged LOS in the PACU, except for patients with asthma (P = 0.003). Different types and durations of surgeries did not significantly contribute to a prolonged PACU stay.

CONCLUSIONS

Our study found that among the various variables examined, asthma, pain, and altered mental status were significantly associated with a prolonged LOS in the PACU. These findings suggest that targeted interventions addressing these factors may help reduce the incidence of prolonged PACU stays and optimize patient outcomes.

Sleep Apnea is Not an Obstacle for Outpatient Hip and Knee Arthroplasty

BACKGROUND

Up to 25% of patients requiring hip or knee arthroplasty have sleep apnea (SA), and these patients have historically been excluded from outpatient programs. The objectives of this study were to evaluate same-day discharge failure as well as 30-day complications, readmissions, and unexpected visits.

METHODS

A retrospective case-control study comparing patients who have and do not have SA matched for age, sex and arthroplasty type (total hip arthroplasty, total knee arthroplasty, unicompartimental knee arthroplasty) who underwent primary outpatient surgery between February 2019 and December 2022 in 2 academic hospitals was conducted. Cases with mild SA, moderate SA with a body mass index (BMI) <35, and SA of all severity treated by continuous positive airway pressure machines were eligible. There were 156 patients included (78 cases). Complications were assessed according to the Clavien-Dindo Classification and the Comprehensive Complication Index. Continuous variables were evaluated by Student's T or Mann-Whitney tests, while categorical data were analyzed by Chi-square or Fisher tests. Univariate analyses were performed to determine discharge failure risk factors.

RESULTS

There were 6 cases (7.7%) and 5 controls (6.4%) who failed to be discharged on surgery day (P = .754), with postoperative hypoxemia (6, [3.8%]) and apnea periods (3, [1.9%]) being the most common causes. Higher BMI (odds ratio = 1.19, P = .013) and general anesthesia (odds ratio = 11.97, P = .004) were found to be risk factors for discharge failure. No difference was observed on 30-day readmissions (P = .497), unexpected visits (P = 1.000), and complications on the Clavien-Dindo Classification (P > .269) and Comprehensive Complication Index (P > .334) scales.

CONCLUSIONS

Selected patients who have SA can safely undergo outpatient hip or knee arthroplasty. Higher BMI and general anesthesia increased the odds of same-day discharge failure.

LEVEL OF EVIDENCE

Level III, Case-control Study.

Body Mass Index Is Not an Independent Factor Associated With Recovery Room Length of Stay for Patients Undergoing Outpatient Surgery

OBJECTIVES

Prolonged recovery time in the postanesthesia care unit (PACU) increases cost and administrative burden of outpatient surgical staff. The primary aim of this study was to determine whether body mass index (BMI) is associated with prolonged recovery in the PACU after outpatient surgery in a freestanding ambulatory surgery center.

METHODS

We retrospectively studied 3 years of surgeries performed at a freestanding ambulatory surgery center. Mixed-effects logistic (for binary outcomes) and linear (for continuous outcomes) regressions were performed, in which the random effect was the surgical procedure. Prolonged PACU length of stay was modeled as a binary variable, that is, stay greater than the third quartile, and as a continuous variable, that is, actual duration of stay in minutes. We reported odds ratio and 95% confidence interval from the logistic regression and estimates with standard errors from the linear regression.

RESULTS

Patients with obesity (BMI ≥ 30 kg/m 2 ) did not demonstrate increased odds for prolonged PACU length of stay (all P > 0.05). Furthermore, BMI-represented as a continuous variable-was not associated with actual PACU length of stay (estimate = 0.05, standard error = 0.06, P = 0.41). No association was found between obesity and PACU length of stay on a subgroup analysis where only patients with obstructive sleep apnea were analyzed.

CONCLUSIONS

There was no association between BMI and PACU length of stay among patients who received outpatient surgery at a freestanding ambulatory surgery center.

Perioperative considerations for cancer patients with obesity: A narrative review

Cancer in patients with obesity has become increasingly common throughout much of the world. Based on our experiences in a specialized cancer center, we have developed a set of standards and expectations that should streamline the surgical journey for this patient population. These recommendations should inform the perioperative management of oncology patients with obesity and help raise awareness of this critical and under-discussed topic.

Utilization and in-hospital complications of catheter ablation for atrial fibrillation in patients with obesity and morbid obesity

Background

Real‐world data on atrial fibrillation (AF) ablation outcomes in obese populations have remained scarce, especially the relationship between obesity and in‐hospital AF ablation outcome.

Hypothesis

Obesity is associated with higher complication rates and higher admission trend for AF ablation.

Methods

We drew data from the US National Inpatient Sample to identify patients who underwent AF ablation between 2005 and 2018. Sociodemographic and patients' characteristics data were collected, and the trend, incidence of catheter ablation complications and mortality were analyzed, and further stratified by obesity classification.

Results

A total of 153 429 patients who were hospitalized for AF ablation were estimated. Among these, 11 876 obese patients (95% confidence interval [CI]: 11 422–12 330) and 10 635 morbid obese patients (95% CI: 10 200–11 069) were observed. There was a substantial uptrend admission, up to fivefold, for AF ablation in all obese patients from 2005 to 2018 (p < .001). Morbidly obese patients were statistically younger, while coexisting comorbidities were substantially higher than both obese and nonobese patients (p < .01) Both obesity and morbid obesity were significantly associated with an increased risk of total bleeding, and vascular complications (p < .05). Only morbid obesity was significantly associated with an increased risk of ablation‐related complications, total infection, and pulmonary complications (p < .01). No difference in‐hospital mortality was observed among obese, morbidly obese, and nonobese patients.

Conclusion

Our study observed an uptrend in the admission of obese patients undergoing AF ablation from 2005 through 2018. Obesity was associated with higher ablation‐related complications, particularly those who were morbidly obese.

Efficacy and Safety of Neuromuscular Blockade in Overweight Patients Undergoing Nasopharyngeal Surgery

BACKGROUND Adequate muscle relaxation and rapid recovery of neuromuscular function are essential in the perioperative period. We therefore compared various anesthetic regimens of neuromuscular blockers and antagonists administered to overweight patients undergoing nasopharyngeal surgery. MATERIAL AND METHODS This prospective, randomized, double-blind study was conducted in overweight patients undergoing nasopharyngeal surgery. We randomly assigned 102 patients into 3 groups (each n=34) treated with various muscle relaxant agents and antagonists: rocuronium and sugammadex (Group RS), rocuronium and neostigmine (Group RN), and cisatracurium and neostigmine (Group CN). Then, we compared the efficacy and safety indexes of the 3 groups. RESULTS Onset times of muscular relaxation in Group RS and Group RN (110 s and 120 s) were shorter than in Group CN (183 s). Time from administration of antagonist to recovery of the TOF ratio to 0.9 was shorter in Group RS (3.3 min) than in other groups (20.7 min and 19.1 min, respectively). The incidence of postoperative residual curarization (PORC) was significantly lower in Group RS (5.9%) than in the other 2 groups (both 41.2%). The hemodynamic parameter changes before extubation were significantly higher in Group RN and Group CN than in Group RS. The postoperative pain scores were lowest in Group RS. CONCLUSIONS For overweight patients undergoing nasopharyngeal surgery, the use of rocuronium with sugammadex had the shortest onset time of neuromuscular relaxation, accelerated the reversion of neuromuscular blockade, effectively reduced the occurrence of PORC, relieved postoperative pain, and maintained hemodynamic stability before extubation. The combination of rocuronium and sugammadex may be the best anesthetic regimen for overweight patients undergoing nasopharyngeal surgery.

Investigation of intraoperative dosing patterns of neuromuscular blocking agents

There is a growing body of literature documenting the use of deep neuromuscular block (NMB) during surgery. Traditional definitions of depth of NMB rely on train-of-four assessment, which can be less reliable in retrospective studies. The goal of our study was to investigate the real-world practice pattern of dosing of neuromuscular blocking agents (NMBA), utilizing the amount of NMBA used during the course of a case, adjusted for patient weight and case duration, as a surrogate measure of depth of NMB. We also aimed to identify case factors associated with larger NMBA doses. In this retrospective observational analysis of our anesthesia information management system, we analyzed all general endotracheal anesthesia cases from 2012 to 2015 in which an intermediate-acting NMBA was used. Cases using a long-acting NMBA or only succinylcholine were excluded. The expected duration of the case was calculated based on the cumulative dose of NMB used, normalized to the patient's ideal body weight and the ED95 of the drug. If the expected duration of the case was greater than the actual case duration documented in the case record, it was classified as higher dosing (HD). If the expected duration was equal to or less than the actual duration, it was considered predicted dosing (PD). Categorical comparisons between HD and PD groups were made for various patient, procedural, and provider factors. 72,684 cases were included in the final analysis, of which 46,358, or 64% of cases, used HD. Cases with patients who were morbidly obese, younger than 65 years, and who were lower ASA Physical Status classification (I or II) used more HD as opposed to PD. Cases that were non-open, used total intravenous anesthesia, emergent cases, or used non-rapid sequence anesthesia induction had higher rates of HD than their matched counterparts. All results were statistically significant. HD was more common in cases that documented train-of-four and used the reversal agent neostigmine. Approximately two-thirds of general endotracheal anesthesia cases using an intermediate-acting NMBA used HD. Cases with higher rates of HD may be those that are traditionally technically complex or emergent, would benefit from greater paralysis, or do not use adjunctive medications for muscle relaxation. Age greater than 65 years was shown to have lower rates of HD, likely due to provider awareness of age-related changes in pharmacokinetics and pharmacodynamics. Intraoperative monitoring and NMB antagonism with neostigmine were used more frequently with HD.

High flow nasal oxygen after bariatric surgery (OXYBAR), prophylactic post-operative high flow nasal oxygen versus conventional oxygen therapy in obese patients undergoing bariatric surgery: study protocol for a randomised controlled pilot trial

BACKGROUND

The incidence of obesity is increasing worldwide. In selected individuals, bariatric surgery may offer a means of achieving long-term weight loss, improved health, and healthcare cost reduction. Physiological changes that occur because of obesity and general anaesthesia predispose to respiratory complications following bariatric surgery. The aim of this study is to determine whether post-operative high flow nasal oxygen therapy (HFNO2) improves respiratory function and reduces the incidence of post-operative pulmonary complications (PPCs) in comparison to conventional oxygen therapy in these patients.

METHOD

The OXYBAR study is a prospective, un-blinded, single centre, randomised, controlled pilot study. Patients with body mass index (BMI) > 30 kg/m2, undergoing laparoscopic bariatric surgery, will be randomised to receive either standard low flow oxygen therapy or HFNO2 in the post-operative period. The primary outcome measure is the change in end expiratory lung impedance (∆EELI) as measured by electrical impedance tomography (EIT). Secondary outcome measures include change in tidal volume (∆Vt), partial arterial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio, incidence of PPCs, hospital length of stay and measures of patient comfort.

DISCUSSION

We hypothesise that the post-operative administration of HFNO2 will increase EELI and therefore end expiratory lung volume (EELV) in obese patients. To our knowledge this is the first trial designed to assess the effects of HFNO2 on EELV in this population. We anticipate that data collected during this pilot study will inform a larger multicentre trial.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000694314 . Registered on 15 May 2017.

Assessment of perioperative minute ventilation in obese versus non-obese patients with a non-invasive respiratory volume monitor

Background

Monitoring the adequacy of spontaneous breathing is a major patient safety concern in the post-operative setting. Monitoring is particularly important for obese patients, who are at a higher risk for post-surgical respiratory complications and often have increased metabolic demand due to excess weight. Here we used a novel, noninvasive Respiratory Volume Monitor (RVM) to monitor ventilation in both obese and non-obese orthopedic patients throughout their perioperative course, in order to develop better monitoring strategies.

Methods

We collected respiratory data from 62 orthopedic patients undergoing elective joint replacement surgery under general anesthesia using a bio-impedance based RVM with an electrode PadSet placed on the thorax. Patients were stratified into obese (BMI ≥ 30) and non-obese cohorts and minute ventilation (MV) at various perioperative time points was compared against each patient’s predicted minute ventilation (MV_PRED) based on ideal body weight (IBW) and body surface area (BSA). The distributions of MV measurements were also compared across obese and non-obese cohorts.

Results

Obese patients had higher MV than the non-obese patients before, during, and after surgery. Measured MV of obese patients was significantly higher than their MV_PRED from IBW formulas, with BSA-based MV_PRED being a closer estimate. Obese patients also had greater variability in MV post-operatively when treated with standard opioid dosing.

Conclusions

Our study demonstrated that obese patients have greater variability in ventilation post-operatively when treated with standard opioid doses, and despite overall higher ventilation, many of them are still at risk for hypoventilation. BSA-based MV_PRED formulas may be more appropriate than IBW-based ones when estimating the respiratory demand of obese patients. The RVM allows for the continuous and non-invasive assessment of respiratory function in both obese and non-obese patients.

Airway management of the morbidly obese patient

A UK study found that obese patients are twice as likely as non-obese patients to develop airway problems during general anaesthesia (Cook et al 2011). This article focuses on airway management of morbidly obese patients during anaesthesia and examines the associated respiratory, gastric, and existing co-morbidity complications that can be expected. Strategies that practitioners can use to reduce these risks are discussed.

Respiratory Muscle Strength, Sound Pressure Level, and Vocal Acoustic Parameters and Waist Circumference of Children With Different Nutritional Status

OBJECTIVE

Relate respiratory muscle strength (RMS), sound pressure (SP) level, and vocal acoustic parameters to the abdominal circumference (AC) and nutritional status of children.

STUDY DESIGN

This is a cross-sectional study.

METHODS

Eighty-two school children aged between 8 and 10 years, grouped by nutritional states (eutrophic, overweight, or obese) and AC percentile (≤25, 25-75, and ≥75), were included in the study. Evaluations of maximal inspiratory pressure (IPmax) and maximal expiratory pressure (EPmax) were conducted using the manometer and SP and acoustic parameters through the Multi-Dimensional Voice Program Advanced (KayPENTAX, Montvale, New Jersey).

RESULTS

There were significant differences (P < 0.05) in the EPmax of children with AC between the 25th and 75th percentiles (72.4) and those less than or equal to the 25th percentile (61.9) and in the SP of those greater than or equal to the 75th percentile (73.4) and less than or equal to the 25th percentile (66.6). The IPmax, EPmax, SP levels, and acoustic variables were not different in relation to the nutritional states of the children. There was a strong and positive correlation between the coefficient of amplitude perturbations (shimmer), the harmonics-to-noise ratio and the variation of the fundamental frequency, respectively, 0.79 and 0.71.

CONCLUSIONS

RMS and acoustic voice characteristics in children do not appear to be influenced by nutritional states, and respiratory pressure does not interfere with acoustic voice characteristics. However, localized fat, represented by the AC, alters the EPmax and the SP, each of which increases as the AC increases.

Laparoscopic versus open obesity surgery: a meta-analysis of pulmonary complications

The clinical effects of laparoscopy in the pulmonary function of obese patients have been poorly investigated in the past. A systematic review was undertaken, with the objective to identify published evidence on pulmonary complications in laparoscopic surgery in the obese. Outcome measures included pulmonary morbidity, pulmonary infection and mortality. The random effects model was used to calculate combined overall effect sizes of pooled data. Data are presented as the odds ratio (OR) with 95% confidence interval (CI). A total of 6 randomized and 14 observational studies were included, which reported data on 185,328 patients. Pulmonary complications occurred in 1.6% of laparoscopic and in 3.6% of open procedures (OR 0.45, 95% CI 0.34-0.60). Pneumonia was reported in 0.5% and in 1.1%, respectively (OR 0.45, 95% CI 0.40-0.51). Available evidence suggests lower pulmonary morbidity for laparoscopic surgery in obese patients; further quality studies are however necessary to consolidate these findings.