Efficacy and safety of patient-controlled analgesia for morbidly obese patients following gastric bypass surgery

Efficacy and Safety of Paragastric Neural Blockade in Controlling Pain, Nausea, and Vomiting After Sleeve Gastrectomy: A Randomized Controlled Trial

BACKGROUND

There are difficulties in controlling the symptoms of pain, nausea, and vomiting after laparoscopic sleeve gastrectomy (LSG). This study aimed to evaluate the efficacy and safety of PGNB on pain and nausea and vomiting in the early postoperative period in patients who underwent LSG.

METHODS

In this prospective, randomized, controlled, double-blind study, the patients were divided into two equally formed groups: patients who underwent PGNB after LSG and the control group. Postoperative pain symptoms were evaluated using the visual analog scale (VAS) scores, and nausea and vomiting symptoms were evaluated using the postoperative nausea and vomiting (PONV) scores.

RESULTS

The study was completed with 90 patients, 45 patients in each group. The VAS scores measured at postoperative hours 1, 6, and 12 were statistically significantly lower in the PGNB group. There was no significant difference between the two groups in terms of the 24th hour VAS scores. The mean PONV scores of the PGNB and control groups were 0.47 ± 0.89 and 1.67 ± 1.95, respectively, revealing a significantly higher value for the controls. The mean time to first mobilization in the postoperative period was significantly shorter in the PGNB group. Upon the evaluation of patient satisfaction, it was determined that the satisfaction score of the PGNB group was significantly higher.

CONCLUSIONS

PGNB is an effective and safe method for managing pain, nausea, and vomiting that occur in the early period after LSG.

Anesthetic management of external iliac artery transection in a morbidly obese patient with Klippel-Trenaunay-Weber syndrome: a case report

BACKGROUND

We report the anesthetic management of an external iliac artery transection in a morbidly obese patient with Klippel-Trenaunay-Weber syndrome (KTWS).

CASE PRESENTATION

A 47-year-old man with KTWS was scheduled for a right external iliac artery transection. Preoperative CT showed a right external iliac artery aneurysm, a right superficial femoral artery aneurysm, and developed collateral vessels. General anesthesia was maintained with desflurane, remifentanil, and rocuronium bromide. After the transection of the right external iliac artery, the regional saturation of oxygen (rSO₂) value of the right femoral did not decrease. There was no significant hemodynamic change before or after the transection. A non-ultrasound-guided rectus abdominis sheath block was performed due to the many collateral vessels. After extubation, the patient did not complain of postoperative pain.

CONCLUSIONS

In the transection of lower-extremity blood arteries under laparotomy in patients with KTWS, rSO₂ monitoring, hemodynamic monitoring, and combined regional anesthesia could be useful.

Considerations for Intravenous Anesthesia Dose in Obese Children: Understanding PKPD

The intravenous induction or loading dose in children is commonly prescribed per kilogram. That dose recognizes the linear relationship between volume of distribution and total body weight. Total body weight comprises both fat and fat-free mass. Fat mass influences the volume of distribution and the use of total body weight fails to recognize the impact of fat mass on pharmacokinetics in children. Size metrics alternative to total body mass (e.g., fat-free and normal fat mass, ideal body weight and lean body weight) have been proposed to scale pharmacokinetic parameters (clearance, volume of distribution) for size. Clearance is the key parameter used to calculate infusion rates or maintenance dosing at steady state. Dosing schedules recognize the curvilinear relationship, described using allometric theory, between clearance and size. Fat mass also has an indirect influence on clearance through both metabolic and renal function that is independent of its effects due to increased body mass. Fat-free mass, lean body mass and ideal body mass are not drug specific and fail to recognize the variable impact of fat mass contributing to body composition in children, both lean and obese. Normal fat mass, used in conjunction with allometry, may prove a useful size metric but computation by clinicians for the individual child is not facile. Dosing is further complicated by the need for multicompartment models to describe intravenous drug pharmacokinetics and the concentration effect relationship, both beneficial and adverse, is often poorly understood. Obesity is also associated with other morbidity that may also influence pharmacokinetics. Dose is best determined using pharmacokinetic-pharmacodynamic (PKPD) models that account for these varied factors. These models, along with covariates (age, weight, body composition), can be incorporated into programmable target-controlled infusion pumps. The use of target-controlled infusion pumps, assuming practitioners have a sound understanding of the PKPD within programs, provide the best available guide to intravenous dose in obese children.

Intraoperative lidocaine infusion as a sole analgesic agent versus morphine in laparoscopic gastric bypass surgery

Background

The aim of this study was to assess the effect of intra-operative intra-venous (IV) lidocaine infusion compared to IV morphine, on the post-operative pain at rest, the intra-operative and post-operative morphine requirements, the sedation and the Modified Aldrete scores in the post-anesthesia care unit (PACU), the hemodynamic parameters; mean values of the mean blood pressure (MBP) and the heart rate (HR), the peri-operative changes in the SpO2, and the respiratory rate (RR) in laparoscopic Roux-en-y gastric bypass. Sixty patients ˃ 18 years old, with body mass index (BMI) ˃ 35 kg/m2, American Society of Anesthesiologists (ASA) physical status II or III, were randomly divided into 2 groups: the lidocaine (L) group patients received intra-operative IV lidocaine infusion, and the morphine (M) group patients received intra-operative IV morphine.

Results

The post-operative numeric pain rating scale (NPRS) at rest was statistically significant less in group L than in group M patients, in the post-operative 90 min in the PACU. This was reflected on the post-operative morphine requirements in the PACU, as 26.6% of patients in group M required morphine with a mean total dose of 10.8 mg. The mean values of the MBP and HR recorded after intubation were comparable between patients of both groups, indicating attenuation of the stress response to endotracheal intubation by both lidocaine and morphine. However, the mean values of the MBP and HR recorded after extubation were statistically significant lower in patients of group L, indicating the attenuation of the stress response to extubation by lidocaine. Patients in group M showed statistically significant lower mean values of the MBP; before pneumoperitoneum and after 15 min from the pneumoperitoneum, this was reflected on statistically significant higher mean values of the HR. Patients in group L showed statistically significant lower mean values of the MBP and the HR; at 30 and 45 min from the pneumoperitoneum. Patients in group L showed statistically significant lower mean values of the MBP; 60 min from the pneumoperitoneum, after release of pneumoperitoneum and in the PACU. Patients of both groups showed comparable mean values of the HR after 60 min from the pneumoperitoneum, after release of the pneumoperitoneum and in the PACU. No patient in either groups developed post-operative respiratory depression in the PACU. Patients in group L showed statistically significant higher median sedation score, which was reflected on statistically but not clinically significant less Modified Aldrete score in patients of group L.

Conclusions

In morbid obese patients, the intra-operative IV lidocaine infusion offered post-operative analgesia in the PACU, on the expense of a higher sedation score, which didn’t affect the Modified Aldrete score clinically, with attenuation of the stress response to endotracheal intubation and extubation.

Trial registrations

FMASU R16/2021. Registered 1st February 2021, with Clinical Trials Registry (NCT05150756) on 10/08/2021.

Enhanced recovery after bariatric surgery: an Italian consensus statement

Background

Enhanced recovery after bariatric surgery (ERABS) is an approach developed to improve outcomes in obese surgical patients. Unfortunately, it is not evenly implemented in Italy. The Italian Society for the Surgery of Obesity and Metabolic Diseases and the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care joined in drafting an official statement on ERABS.

Methods

To assess the effectiveness and safety of ERABS and to develop evidence-based recommendations with regard to pre-, intra-, and post-operative care for obese patients undergoing ERABS, a 13-member expert task force of surgeons and anesthesiologists from Italian certified IFSO center of excellence in bariatric surgery was established and a review of English-language papers conducted. Oxford 2011 Levels of Evidence and U.S. Preventive Services Task Force Grade Definitions were used to grade the level of evidence and the strength of recommendations, respectively. The supporting evidence and recommendations were reviewed and discussed by the entire group at meetings to achieve a final consensus.

Results

Compared to the conventional approach, ERABS reduces the length of hospital stay and does not heighten the risk of major post-operative complications, re-operations, and hospital re-admissions, nor does it increase the overall surgical costs. A total of 25 recommendations were proposed, covering pre-operative evaluation and care (7 items), intra-operative management (1 item, 11 sub-items), and post-operative care and discharge (6 items).

Conclusions

ERABS is an effective and safe approach. The recommendations allow the proper management of obese patients undergoing ERABS for a better outcome.

Pharmacokinetic Pharmacodynamic Modelling Contributions to Improve Paediatric Anaesthesia Practice

The use of pharmacokinetic-pharmacodynamic models has improved anaesthesia practice in children through a better understanding of dose-concentration-response relationships, developmental pharmacokinetic changes, quantification of drug interactions and insights into how covariates (e.g., age, size, organ dysfunction, pharmacogenomics) impact drug prescription. Simulation using information from these models has enabled the prediction and learning of beneficial and adverse effects and decision-making around clinical scenarios. Covariate information, including the use of allometric size scaling, age and consideration of fat mass, has reduced population parameter variability. The target concentration approach has rationalised dose calculation. Paediatric pharmacokinetic-pharmacodynamic insights have led to better drug delivery systems for total intravenous anaesthesia and an expectation about drug offset when delivery is stopped. Understanding concentration-dependent adverse effects have tempered dose regimens. Quantification of drug interactions has improved the understanding of the effects of drug combinations. Repurposed drugs (e.g., antiviral drugs used for COVID-19) within the community can have important effects on drugs used in paediatric anaesthesia, and the use of simulation educates about these drug vagaries.

Authorized Agent-Controlled Analgesia for Pain Management in Critically Ill Adult Patients

BACKGROUND

Patient-controlled analgesia is commonly used for adult patients requiring parenteral opioid analgesia in the postoperative setting. However, many patients are unable to use patient-controlled analgesia because of physical or cognitive limitations. Authorized agent-controlled analgesia, in which a nurse or family member activates the patient-controlled analgesia device, has been studied in the pediatric population but has received little attention in adults.

OBJECTIVE

To evaluate the efficacy of authorized agent-controlled analgesia in critically ill adult patients.

METHODS

A retrospective pilot study was conducted involving 46 patients who were placed on an authorized agent-controlled analgesia protocol in a mixed medical/surgical adult intensive care unit. Critical-Care Pain Observation Tool scores were abstracted for the 24 hours before and after initiation of authorized agent-controlled analgesia. Authorized agent-controlled analgesia was administered by nurses only.

RESULTS

The mean (SD) change in pain score was -3.4 (2.0) (95% CI, -4.0 to -2.7), representing a 69% decrease in the mean (SD) pain score from before to after initiation of authorized agent-controlled analgesia (4.8 [1.8] vs 1.5 [1.6]; P < .001). When the results were controlled for time, sedative administration, and opioid medication administration, the effect of authorized agent-controlled analgesia initiation on pain scores remained significant (P < .001).

CONCLUSIONS

Use of authorized agent-controlled analgesia is associated with a reduction in pain in critically ill patients. Larger studies are warranted to confirm these findings.

Ketamine infusion reduces narcotic requirements following gastric bypass surgery: a randomized controlled trial

BACKGROUND

As the obesity epidemic worsens, anesthesiologists should expect to see more obese patients presenting for surgical procedures. Opioids cause respiratory depression, which has caused complications in patients with obstructive sleep apnea. Opioids can also cause nausea, prolonging the time that patients spend in the postanesthesia care unit. Ketamine is a potential analgesic alternative that may have advantages to narcotics in the bariatric population.

OBJECTIVES

To determine whether an intraoperative ketamine infusion would reduce postoperative narcotic use in patients during the first 48 hours after laparoscopic gastric bypass.

SETTING

Major academic medical center.

METHODS

There were 54 participating patients. The intervention group (n = 27) was randomized to receive 100 μg of fentanyl with anesthesia induction, then a 20-mg bolus of ketamine, followed by a 5 μg/kg/min intraoperative ketamine infusion starting after anesthesia induction and ending after wound closure commenced. The control group (narcotic only, n = 27) also received 100 μg of fentanyl at anesthesia induction and intraoperative boluses of fentanyl at the discretion of the anesthesia team, with .3 mg of hydromorphone administered approximately 45 minutes before the completion of surgery.

RESULTS

At 24 hours, the mean morphine-equivalent units (MEUs) were 12.7 (standard deviation [SD], 9.9; 95% confidence interval [CI], 8.8-16.6) for the ketamine group (n = 28) and 16.5 (SD, 9.8; 95% CI, 12.6-20.4) for the control group (n = 28). At 48 hours, the MEUs were 16.7 (SD, 12.0; 95% CI, 11.9-21.4) for the ketamine group and 22.7 (SD, 14.9; 95% CI, 16.8-28.6) for the control group. Cumulative MEUs for 24 hours (P = .039) and 48 hours (P = .058) postoperatively were lower in the ketamine group compared with the narcotic-only (control) group, although the difference at 48 hours did not reach statistical significance. Compared with the narcotic-only group, the ketamine group used 26% fewer MEUs after 24 hours and 31% fewer MEUs after 48 hours. This difference can mostly be attributed to group differences during the first 6 hours after surgery.

CONCLUSIONS

Ketamine successfully reduced the amount of opioids required to control bariatric patients' pain at 24 hours postoperatively, but not over the 48-hour postoperative period.

Advances in pharmacokinetic modeling: target controlled infusions in the obese

PURPOSE OF REVIEW

The use of conventional pharmacokinetic parameters sets 'models' derived from nonobese patients has proven inadequate to administer intravenous anesthetics in the obese population and is commonly associated with higher than anticipated plasma propofol concentrations when used with target (plasma or effect site) controlled infusion pumps. In this review we will describe recent modeling strategies to characterize the disposition of intravenous anesthetics in the obese patient and will show clinically relevant aspects of new model's performance in the obese population.

RECENT FINDINGS

Because clearance of a drug increases in a nonlinear manner with weight, nonlinear relationships better scale infusion rates between lean and obese individuals. Allometric concepts have been successfully used to describe size-related nonlinear changes in clearances. Other nonlinear scaling options include the use of descriptors such as body surface area, lean body weight, fat-free mass, and normal fat mass. Newer pharmacokinetic models, determined from obese patient data, have been developed for propofol and remifentanil using allometric concepts and comprehensive size descriptors.

SUMMARY

Pharmacokinetic models to perform target-controlled infusion in the obese population should incorporate descriptors that reflect with greater precision the influence of body composition in volumes and clearances of each drug. It is our hope that commercially available pumps will soon incorporate these new models to improve the performance of this technique in the obese population.

An enhanced recovery program for bariatric surgical patients significantly reduces perioperative opioid consumption and postoperative nausea

BACKGROUND

Patients frequently remain in the hospital after bariatric surgery due to pain, nausea, and inability to tolerate oral intake. Enhanced recovery after surgery (ERAS) concepts address these perioperative complications and therefore improve length of stay for bariatric surgery patients.

OBJECTIVES

To determine if ERAS concepts increase the proportion of patients discharged on postoperative day 1. Secondary objectives included mean length of stay, perioperative opioid use, emergency department visits, and readmissions.

SETTING

A large metropolitan university tertiary hospital.

METHODS

A quantitative before and after study was conducted for patients undergoing bariatric surgical patients. Data were collected surrounding length of stay, perioperative opioid consumption, antiemetic therapy requirements postoperatively, multimodal analgesia compliance, emergency department visits, and hospital readmission rates. Wilcoxon rank-sum and χ² test were used to compare continuous and categorical variables, respectively. A secondary analysis was performed using Aligned Rank Transformation and Cochran-Mantel-Haenszel χ² tests to account for an increase in sleeve gastrectomies in the intervention group.

RESULTS

The 2 groups had clinically similar baseline characteristics. Comparison group (N = 366) and ERAS group (N = 715) patients underwent a primary bariatric surgery procedure. There was an increase in the number of patients undergoing a laparoscopic sleeve gastrectomy in the intervention group. After accounting for this increase, the percentage of patients discharged on postoperative day 1 was unchanged (79.8% non-ERAS versus 83.1% ERAS, P = .52). ERAS length of stay was statistically significantly lower for gastric bypass (P<.001) and robotic gastric bypass (P = .01). Perioperative opioid consumption was reduced (41.0 versus 16.2 morphine equivalents, P<0.001), and fewer ERAS patients required postoperative antiemetics (68.8% versus 46.2%, P<.001). Emergency department visits at 7 days were reduced (6.0% versus 3.2%, P = .04), but hospital readmission rates were unchanged.

CONCLUSIONS

Implementing ERAS did not reduce the percentage of patients discharged on postoperative day 1 in a bariatric surgery program with historically low length of stay, but it led to significant reductions in perioperative opioid use, decreases in postoperative nausea, and early emergency room visits.

What is the best size predictor for dose in the obese child?

Lean body mass is commonly proposed for anesthesia maintenance drug dosing calculations. However, total body mass used with allometric scaling has been shown to be better for propofol in obese adults and children. Fat-free mass has also been used instead of lean body mass. Fat-free mass is essentially the same as lean body mass but excludes a small percentage of mass of lipids in cell membranes, CNS, and bone marrow. Normal fat mass is a size descriptor that partitions total body mass into fat-free mass and fat mass calculated from total body mass minus fat-free mass. The relative influence of fat mass compared with fat-free mass is described by the fraction of fat mass that makes fat equivalent to fat-free mass in terms of allometric size. This fraction (Ffat) will differ for each drug and each parameter affected by body size (eg, clearance and volume of distribution). This fraction is based on the concept of theory-based allometric size. The normal fat mass based on allometric theory and partition of body mass into fat and fat-free components provides a principle-based approach explaining size and body composition effects on pharmacokinetics of all drugs in children and in adults.

Anesthetic Considerations in Patients Undergoing Bariatric Surgery: A Review Article

Context

This article discusses the anesthetic considerations in patients undergoing bariatric surgery in the preoperative, intraoperative, and postoperative phases of surgery.

Evidence Acquisition

This review includes studies involving obese patients undergoing bariatric surgery. Searches have been conducted in PubMed, MEDLINE, EMBASE, Google Scholar, Scopus, and Cochrane Database of Systematic Review using the terms obese, obesity, bariatric, anesthesia, perioperative, preoperative, perioperative, postoperative, and their combinations.

Results

Obesity is a major worldwide health problem associated with many comorbidities. Bariatric surgery has been proposed as the best alternative treatment for extreme obese patients when all other therapeutic options have failed.

Conclusions

Anesthetists must completely assess the patients before the surgery to identify anesthesia- related potential risk factors and prepare for management during the surgery.

Does epidural morphine loading in addition to thoracic epidural analgesia benefit the postoperative management of morbidly obese patients undergoing open bariatric surgery? A pilot study

BACKGROUND

Insufficient data exist regarding postoperative thoracic epidural analgesia for morbidly obese patients undergoing open bariatric surgery. This study evaluated the effectiveness of morphine loading in a postoperative thoracic epidural analgesic regimen of patient-controlled epidural analgesia (PCEA) with levobupivacaine combined with continuously administered epidural morphine in this patient group.

METHODS

In this prospective randomized controlled trial, 48 superobese patients (body mass index of ≥ 50 kg/m(2)) undergoing open bariatric surgery were randomly allocated to three groups of 16 patients each. Postoperatively, all groups received a continuous epidural morphine infusion of 0.2 mg/h with 0.1 % levobupivacaine via PCEA. Group A did not receive intraoperative epidural morphine loading, while groups B and C received an intraoperative 1- and 2-mg morphine bolus, respectively. Levobupivacaine consumption via PCEA (primary outcome), pain scores at rest and on cough, the time to return of bowel function and ambulation, and arterial blood gas levels (secondary outcomes) were recorded.

RESULTS

The increase in perioperative morphine administration (groups B and C) led to a significantly prolonged return to normal bowel function and delayed ambulation (P<0.05 to 0.01, respectively), without an improvement in postoperative analgesia or a reduction in local anesthetic consumption. Although the prevalence of obstructive sleep apnea (OSA) was high in all groups, no respiratory depression was observed.

CONCLUSIONS

Thoracic PCEA with 0.1 % levobupivacaine combined with continuous epidural morphine administration of 0.2 mg/h without morphine loading is an effective postoperative analgesic regimen that provides adequate pain control, early ambulation, and early return of bowel function in superobese patients, particularly those with OSA.

Scheduled intravenous acetaminophen reduces postoperative narcotic analgesic demand and requirement after laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Intravenous (i.v.) acetaminophen has the potential to reduce postoperative narcotic analgesic requirement but this has not been reported in bariatric surgery. As lower dosages could reduce undesirable narcotic side effects, we investigated the opioid-sparing effect of concomitant i.v. acetaminophen in bariatric surgery.

METHODS

We performed a retrospective review of our electronic medical records of laparoscopic Roux-en-Y gastric bypasses (LRYGB) performed for severe obesity between 2011 and 2013. We identified 183 patients that received scheduled i.v. acetaminophen in addition to morphine sulfate (MSO4) patient-controlled analgesia (PCA). A cohort of 229 patients from the preceding 2 years who were treated with MSO4 PCA but not acetaminophen was used as a historical control. Patient demographic characteristics and narcotic use data were extracted from electronic medical records. Student's t test or linear regression was used as appropriate (P< .05).

RESULTS

During the first 24-hour postoperative period after LRYGB, narcotic analgesic demand (total PCA demand including nondelivery of narcotic due to lock-out) was reduced by 25% with the concomitant use of i.v. acetaminophen (40.5 versus 30.9 average pushes; P<.05). During the same period, narcotic analgesic dosage requirement was cut down by 20% in the study group (average of 29.9 versus 24.1 mg of MSO4; P<.05). Linear regression analysis confirmed that these changes were independent of age, gender, and body mass index distribution, or type 2 diabetes mellitus.

CONCLUSION

Scheduled i.v. acetaminophen reduces the demand for and the requirement of narcotic analgesia after LRYGB. We provide new evidence in support of the routine use of multimodal analgesia that includes scheduled i.v. acetaminophen in the initial 24-hour period after bariatric surgery.

Challenges in the optimisation of post-operative pain management with opioids in obese patients: a literature review

An increasing number of obese patients are undergoing surgery, particularly bariatric and orthopaedic surgery. The physiological differences between obese and normal-weight subjects may modify not only anaesthetic requirements during surgery but also post-operative analgesic management, raising a number of challenges in a critical period. In this review, we analyse studies of post-operative pain management with opioids in obese subjects. We discuss the genetic factors common to pain and obesity and the factors potentially modifying opioid pharmacokinetics and pharmacodynamics in obese patients, and we analyse the overall efficacy and safety of opioids for pain management during the post-operative period in obese patients. Both modifications to surgical methods and additional analgesic treatments to decrease the requirement for opioids may improve early rehabilitation and quality of care and reduce adverse effects in obese patients.

Liposome bupivacaine for postsurgical pain in an obese woman with chronic pain undergoing laparoscopic gastrectomy: a case report

Introduction

To reduce incidence and severity of postsurgical pain and minimize the effect of its clinical and economic correlates, multimodal therapy for surgical patients is recommended. In this report, we discuss the use of liposome bupivacaine, a novel multivesicular formulation of bupivacaine indicated for single-dose infiltration into the surgical site to produce postsurgical analgesia, as part of a multimodal analgesic regimen in a patient with a history of chronic pain scheduled to undergo laparoscopic sleeve gastrectomy. To the best of our knowledge, this is the first published report of liposome bupivacaine in the setting of laparoscopic sleeve gastrectomy.

Case presentation

A 35-year-old white woman with morbid obesity was admitted for laparoscopic sleeve gastrectomy to lose weight prior to hip replacement surgery. Because of a complicated medical history that included rheumatoid arthritis, fibromyalgia, diabetes mellitus, hypertension, and chronic pain, for which she was receiving high doses of opioid analgesics, postsurgical pain management was a concern and she was considered a candidate for multimodal analgesia. At initiation of surgery, 50mL of lidocaine and epinephrine was infiltrated around the port sites. At the conclusion, 25mL of normal sterile saline was added to a 20mL vial of liposome bupivacaine (266mg) and injected around the port sites and at the site of liver retraction. Laparoscopic sleeve gastrectomy was successfully completed. Our patient was discharged to the postanesthesia care unit for approximately four hours before discharge to the surgical floor with a pain score of 5 (11-point scale; 0 = no pain, 10 = worst possible pain). Her postoperative course was uneventful; no adverse events were recorded during surgery or during the remainder of her hospital stay. Our patient was discharged on the same opioid regimen used previously for control of her preexisting chronic pain.

Conclusions

Liposome bupivacaine use in this morbidly obese patient undergoing laparoscopic sleeve gastrectomy provided analgesic efficacy and limited postsurgical opioids to a level comparable with her baseline opioid regimen for chronic pain. Given her complex medical history and previous issues with acute and chronic pain, we consider these results highly successful and continue to use liposome bupivacaine as part of a multimodal analgesic regimen in an effort to optimize postsurgical pain management.

Anesthetizing the obese child

The prevalence of childhood obesity is increasing. The focus of this review is the special anesthetic considerations regarding the perioperative management of obese children. With obesity the risk of comorbidity such as asthma, obstructive sleep apnea, hypertension, and diabetes increases. The obese child has an increased risk of perioperative complications especially related to airway management and ventilation. There is a significantly increased risk of difficult mask ventilation and perioperative desaturation. Furthermore, obesity has an impact on the pharmacokinetics of most anesthetic drugs. This has important implications on how to estimate the optimal drug dose. This article offers a review of the literature on definition, prevalence and the pathophysiology of childhood obesity and provides suggestions on preanesthetic evaluation, airway management and dosage of the anesthetic drugs in these patients. The authors highlight the need of supplemental studies on various areas of the subject.

Postoperative pain management of the obese patient

In the obese patient, the goal of postoperative pain management is provision of comfort, early mobilisation and improved respiratory function without causing inadequate sedation and respiratory compromise. The pathophysiology of obesity, typical co-morbidities and the high prevalence of obstructive sleep apnoea (OSA) amongst obese patients make safe analgesic management difficult. In particular, pain control after bariatric surgery is a major challenge. Although several reviews covering anaesthesia and analgesia for obese patients are published, there is mainly expert opinion and a paucity of evidence-based recommendations. Advice on general management includes multimodal analgesic therapy, preference for regional techniques, avoidance of sedatives, non-invasive ventilation with supplemental oxygen, early mobilisation and elevation of the head of bed to 30 degrees. Finally, with regard to monitoring, sedation scoring is most relevant, but there should be a low threshold for continuous pulse oxymetry, arterial blood pressure measurement and placement in a high-dependency area for the postoperative period.

Perianesthesia respiratory care of the bariatric patient

Our nation's obesity problem has reached epidemic proportions and is only projected to worsen. The morbidly obese patient is at risk for experiencing a multitude of health-related conditions. Morbidly obese patients are presenting for surgery at an increasing rate, especially with the growing popularity of weight-loss surgery. Therefore the perianesthesia nurse has to remain informed of optimal care strategies for this sometimes challenging population. The obese patient presents with distinct respiratory care considerations of which the perianesthesia nurse must be knowledgeable. This review article will specifically focus on the respiratory care of the bariatric patient presenting for surgery.

Best practice recommendations for anesthetic perioperative care and pain management in weight loss surgery

OBJECTIVE

To develop evidence-based recommendations that optimize the safety and efficacy of perioperative anesthetic care and pain management in weight loss surgery (WLS) patients.

RESEARCH METHODS AND PROCEDURES

This Task Group examined the scientific literature on anesthetic perioperative care and pain management published in MEDLINE from January 1994 to March 2004. We also reviewed additional data from other sources (e.g., book chapters). The search yielded 195 abstracts, of which 35 references were reviewed in detail. Task Group consensus was used to provide recommendations when evidence in the literature was insufficient.

RESULTS

We developed anesthesia practice and patient safety advisory recommendations for preoperative evaluation, intraoperative management, and postoperative care and pain management of WLS patients. We also provided suggestions related to medical error reduction and systems improvements, credentialing, and future research.

DISCUSSION

Obesity-related comorbidities including obstructive sleep apnea place WLS patients at increased risk for complications perioperatively. Regarding perioperative safety and outcomes, conclusive evidence beyond the accepted standard of care in the reviewed literature is limited. Few reports specifically address the perioperative needs of severely obese patients. In this advisory, we synthesize current knowledge and make best practice recommendations for perioperative care and pain management in WLS patients. These recommendations require periodic review as further medical knowledge and evidence evolve.

Intravenous patient-controlled analgesia: one size does not fit all

Patient-controlled analgesia was introduced as a technique that would allow greater flexibility in opioid delivery for the management of acute pain. However, so far, any benefit compared with conventional methods of pain relief appears to be small. This article reviews some of the factors that could limit the usefulness of intravenous patient-controlled analgesia in the clinical setting and what strategies might allow patient-controlled analgesia to become more effective.

Resuscitation of the morbidly obese patient

Obesity is a major health care problem in the United States. The body mass index (BMI) is the standard measure of obesity. A BMI >25 kg/m2 is defined as overweight and obesity as a BMI > 30 kg/m2. Recent surveys indicate that 54% of adults, or roughly 97 million people, are overweight. Given the incidence of obesity in the general population, it is likely that EM physicians will be involved in the emergency care of critically ill or injured obese patients. The objective of this article is to present the clinical problems associated with the resuscitation of the critically ill or injured obese patient and their potential solutions.

Patient controlled i.v. analgesia is an acceptable pain management strategy in morbidly obese patients undergoing gastric bypass surgery. A retrospective comparison with epidural analgesia

PURPOSE

To examine the hypothesis that pain treatment with patient controlled analgesia (PCA) using iv morphine is a suitable and safe alternative to epidural analgesia in morbidly obese patients undergoing gastric bypass surgery. We retrospectively compared the postoperative periods in all patients undergoing this procedure in our institution between November 1999 and November 2001.

METHODS

According to their perioperative pain treatment, patients were assigned to a PCA group (with iv morphine) or an epidural analgesia group, in which patients received either intermittent doses of morphine or continuous infusions of bupivacaine/fentanyl. Study endpoints included quality of pain control, incidence of cardiovascular and respiratory complications, analgesia related side effects, time to ambulation and first flatus, length of hospital stay, and wound infections.

RESULTS

Data from 86 patients were analyzed with 40 patients in the PCA group and 46 patients in the epidural group. Groups were similar with respect to age, body mass index, and gender. The type of analgesia did not affect the quality of pain control at rest, the frequency of nausea and pruritus, the time to ambulation and return of gastrointestinal function, and the length of hospital stay. Patients receiving epidural analgesia had a greater risk of wound infection than subjects with PCA (epidural group: 39%, PCA group: 15%, P = 0.01).

CONCLUSION

We conclude that in grossly obese patients undergoing gastric bypass surgery PCA with iv morphine is an acceptable strategy for pain management and may confer some advantages when compared to epidural analgesia.

Evaluation of the effective drugs for the prevention of nausea and vomiting induced by morphine used for postoperative pain: a quantitative systematic review

Postoperative nausea and vomiting (PONV) with morphine therapy develops in more than 60% of patients after surgery, markedly reducing patient QOL. The prophylactic effect of several antiemetics has already been studied, but evaluations, and even those using the same drug, are not uniform. The present research involved a meta-analysis of randomized controlled trials on prophylactic drug therapy for PONV in patients receiving morphine for the treatment of postoperative pain. The efficacy of the prophylactic administration of the drugs was examined. As a result, meta-analysis of five drugs was possible and the evidence of efficacy was shown for three drugs ranked in order of an increasing odds ratio (OR) and confidence interval (CI): dexamethasone (OR: 0.23, 95% CI: 0.15-0.35, p < 0.00001), droperidol (OR: 0.27, 95% CI: 0.21-0.34, p < 0.00001), and metoclopramide (OR: 0.48, 95% CI: 0.30-0.75, p < 0.001). These results suggest that the three drugs are effective in prophylactic treatment for PONV. Of them, dexamethasone used as a prophylactic drug for PONV provided the best results. Dexamethasone was shown to reduce the incidence of PONV from 66-80% to 16-50% with a dose of 1.25 to 10 mg and to be suitable as a first drug of choice.