Anesthetic Considerations In Bariatric Surgery

Issues of Concern

Physiologic Changes of Obesity

Physiologic changes related to obesity are compounded and interlock over time. Cardiovascular insults of obesity increase a patient's risk of developing hypertension, dyslipidemia, coronary artery disease, arrhythmias, and systolic and diastolic heart failure. In this instance, heart failure can be worsened with increased intravascular volume and a lower systemic vascular resistance. When combined with hypertension, a higher stroke volume, and a more significant workload, left-sided hypertrophy can result. 

Obese body habitus causes a physical restriction of diaphragmatic excursion and compression from increased external and internal adipose tissue surrounding the airway. This leads to decreased functional residual capacity (FRC), expiratory reserve volume (ERV), total lung volume (TLV), and increased closing capacity (CC). As a result, the respiratory rate typically increases to meet demand and attempt to offset ventilation-perfusion mismatch. Genetic components drive where and how fat deposition occurs in and around the airway, causing decreased muscle tone from intramuscular fatty deposits and excessive tissue from extra-muscular deposition. Poorly optimized or undiagnosed obstructive airway disease worsens metabolic stress and increases hypercapnia. The build-up of respiratory challenges can increase workload and thus precipitate or exacerbate right-sided heart failure.[9]

Chronic inflammation and endothelial changes result in an increased risk for thrombophlebitis. This, combined with undiagnosed or poorly treated obstructive sleep apnea (OSA), increases the risk for neurologic complications such as strokes. 

Obesity also affects the reproductive system, especially in females, including polycystic ovary syndrome and infertility. 

Insulin resistance and diabetes often compound gastrointestinal (eg, gastroparesis) and renal disease. Chronic kidney disease, BMI greater than 50 kg/m², and prolonged surgical procedures are important risk factors for postoperative renal dysfunction.[14] A recent trend in obesity assessment also considers the presence and extent of pancreatitis, liver steatosis, and cirrhosis. Cirrhosis alone can lead to worsening pulmonary hypertension, right heart failure, and renal and hematologic dysfunction. Chronic noncancer pain and osteoarthritic (knee and back) pain compound these conditions and add to a vicious cycle of decreased mobility, weight gain, and depression. This further impacts a patient's psychological health and well-being.[2][3][10]

Consensus on Bariatric Surgery

Guidelines initially released in the 1991 consensus statement by the National Institute of Health were amended in 2022 by a joint statement of the American Society of Metabolic and Bariatric Surgery (ASBMS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) address the expanding definition of obesity. The new recommendations indicate metabolic and bariatric surgery (MBS) may be appropriate for individuals with a BMI greater than or equal to 35 kg/m², regardless of the presence, absence, or severity of comorbidities. They can be considered for individuals with a BMI greater than or equal to 30 kg/m² and concurrent metabolic disease, such as diabetes. ASMBS also suggests that the BMI thresholds should be adjusted in the Asian population. Accordingly, an individual with a BMI greater than or equal to 27.5 kg/m² should be offered MBS due to increased truncal adiposity and its attendant risks within this population.[11][12]  This inclusive approach to patient selection is also supported by the Enhanced Recovery After Surgery (ERAS) Society guidelines updated in 2021. The goals of ERAS guidelines in procedures are to improve patient outcomes and decrease complications.[13]

Types of Bariatric Surgery

There are several types of bariatric surgery currently in use that work by either restrictive or malabsorptive effects or a combination: adjustable gastric bands, gastric "sleeve," vertical banded gastroplasty, Roux-en-Y gastric bypass (with or without a duodenal switch), and endoscopically placed balloons.

Gastric bands are adjustable bands that reduce the stomach opening by external compression. They were initially seen as a less aggressive approach with reversibility if the outcomes were not desirable to the patient. Presently, they are utilized with decreasing frequency because of patient intolerance to the device, compression, food restriction, and the incidence of complications, including device erosion and perforation into the stomach, causing many patients to move on to more permanent surgical techniques. [14]

A vertical banded gastroplasty or "sleeve" gastrectomy aims to permanently decrease the size of the stomach to decrease the amount of food the stomach can accommodate. A vertical banded gastroplasty involves a staple line separating the stomach from the esophagus near the antrum and a band placed to limit the volume moving through at any time. In sleeve gastrectomy, the stomach is permanently resected to a much smaller "banana shape" and left in continuity with the intestines. Digestive hormones, gastrointestinal biome, and vagal innervation may be affected in this surgery due to the resected tissue, which reduces the volume of food that can enter the stomach at any given time. The desired result is that it takes much longer to ingest and process a given volume of food, thus limiting overall daily intake.[15]

The Roux-en-Y gastric bypass creates a small gastric pouch and anastomosis to a Roux limb of the jejunum that bypasses 75 to 150 cm of the small bowel, thereby restricting food volume at any given time and limiting absorption. Alternatively, a biliopancreatic diversion with a duodenal switch is associated with a more malabsorptive technique. The duodenal switch carries a greater risk for surgical complications but may be recommended for patients with severe obesity and diabetes. The duodenal switch reduces the size of the stomach by approximately 60% to 70% (versus 70% to 80% with a Roux-en-Y.)[16]

Other endoscopically placed space-occupying or gate-keeping devices, such as gastric balloons, have also been introduced to control the amount or duration of time food is processed in the stomach. However, the United States Food and Drug Administration has not fully assessed the long-term effects and outcomes of these devices.

Complications of bariatric surgeries include but are not limited to aspiration, strictures, suture line dehiscence, chronic nausea and vomiting, malnutrition, and "dumping syndrome" due to the malabsorption of food during digestion and postprandial reactive hypoglycemia.[17] Thorough patient understanding of surgical changes and lifestyle modifications is paramount. Bariatric surgery patients undergo a rigorous preoperative review driven by the ASMBS guidelines. "A multi-disciplinary team with access to medical, surgical, psychiatric, and nutritional expertise" that includes dietitians, a psychiatrist or psychologist, internal medicine or other subspecialists take a complete medical and psycho-social review of the patient to help prepare and educate patients on the initial and long-term outcomes of the procedure. The team should perform a cardiovascular (ie, electrocardiogram, echocardiogram), pulmonary (ie, smoking cessation encouragement, sleep apnea review), and gastroenterological workup (endoscopy) before the day of service.[11]  The goal is to review the patient's overall health status and educate them about the procedure and the hoped-for outcomes.[18] 

Contraindications to Surgery

According to the ASMBS guidelines, bariatric surgery has no absolute contraindications. Many institutions and individual providers have relative contraindications primarily based on long-term fitness for surgery and wound healing. Frail patients and those at extremes of age, severe illness, or disease states (such as end-stage liver disease, severe pulmonary hypertension, active cancer treatment, or unstable or degenerating cardiac status) would place the patient in a higher risk category than most programs consider acceptable. Active or untreated alcohol or drug use disorder, untreated or unstable psychiatric illness, or signs of unwillingness to comply with the necessary dietary and lifestyle changes required to adjust to postoperative changes are barriers to obtaining bariatric surgery.[18]

ERAS protocols for bariatric surgeries promote pre-admission education of dietary and lifestyle accommodations that are required before surgery, including but not limited to rehabilitation exercise, drug or alcohol use disorder recovery for 1 to 2 years, and greater than or equal to 4 weeks of smoking cessation before the day of surgery. The reviewing committee strongly encourages these changes to improve outcomes but admits that low to moderate levels of data currently support most of these suggestions.[19]

Anesthetic Choices

Preoperative

All-cause morbidity and mortality are increased when BMI is greater than 50 kg/m². Typically, bariatric procedures are performed as inpatient procedures, given the comorbidities associated with this patient population and the need for extended surgical postoperative care. Ideally, the patient should be assessed by an anesthesia provider for fitness for anesthesia at the scheduled surgery location before the day of service.[20]  

All patients should undergo a rigorous and appropriate preoperative anesthetic evaluation. Beyond medical history review, preoperative anesthesia assessments should examine the current medication regimen and the patient's day of service status. Longer-acting medications for diabetes, blood pressure, pain control, anxiety, and anticoagulation may have activities during the perioperative period where risks for hypoglycemia, withdrawal, thrombosis, and bleeding are increased. Vigilance to blood glucose and diabetic responses, especially in those patients using longer-acting medications who are nil per os (NPO), includes monitoring and hand-off communication to staff throughout the perioperative period. Recently released guidelines from the American Society of Anesthesiologists (ASA) regarding patients taking glucagon-like-peptide (GLP-1) receptor agonists receiving anesthesia suggest the last medication administration be at least one week from the day of surgery. Additional suggestions include prolonged NPO times of up to 16 hours and point-of-care ultrasound for gastric contents assessment in the immediate preoperative period. These guidelines are based on many anecdotal reports of retained solid food contents in patients' stomachs who were known to be appropriately NPO before surgery. They are also based upon the half-life of many medications, approximately 5 to 7 days. This decreases the risk of aspiration of retained stomach contents due to slowing gastric emptying time. Other concerns for patients on the GLP-1 receptor agonists and other long-acting diabetic medications include considerations for hypoglycemia in the instance of little to no oral intake with patients who remain NPO after the procedures.[21]  

A standard preoperative assessment of the airway should be performed. Not all obese patients have difficult airways, but the comorbidities and habitus can make them more challenging. In an upright position, the patient is assessed for cervical range of motion (extension, flexion, rotation), mandibular movement (protrusive, retrusion), mouth opening range, and the Mallampati score. Thyromental and interincisal distance, missing, overlapping, loose dentition, and palatal tori should also be noted. Neck circumference, the ease or difficulty of visualizing or palpating the angle of the jaw and mandible, and the distribution of adipose tissue on the back of the neck indicate the possible limitations of neck mobility, difficulties with bag-mask ventilation, and preoxygenation of the patient. A history of a difficult airway with anesthesia in the past should also be noted. Adipose tissue and body habitus can also make intravenous (IV) access and monitoring more difficult. Longer IV needles, ultrasound guidance, and even central line IV access may be required to reach the veins. Intra-arterial blood pressure monitoring should be considered if noninvasive pressure monitoring cannot be consistently obtained by cuff pressure. Using an ultrasound to aid in success should also be considered here.

Anesthetic goals for postoperative reduction of postoperative vomiting (PONV) and respiratory depression begin in the preoperative phase. Preoperative medications may include anxiolytics (ie, benzodiazepines), antisialagogues (ie, glycopyrrolate), and preemptive antiemetics (ie, IV steroids and transdermal scopolamine patches). Pain control can be provided by multimodal techniques of anti-inflammatories, antispasmodic, and opioids in the oral form preoperatively. Prior anxiolytic and pain medication use and tolerance should be discussed as part of the preanesthetic assessment and used to guide pain treatment throughout the anesthetic. Caution is necessary with premedication because of the synergistic effect of anxiolytics and opioids in this patient population with a high risk for respiratory depression. 

Preoperative ERAS protocols have low levels of evidence for the suggestions for IV dexamethasone 8 mg, maintenance of patient beta-blockers and statins (if present), preoperative fasting of solid foods 6 hours before surgery but allowing a carbohydrate beverage for loading 2 hours before the procedure. However, their supportive data is much higher, and they strongly encourage using a multimodal pain management technique (including regional anesthetic techniques such as thoracic epidurals for laparotomy approach) to manage pain and avoid PONV.[22]

Intraoperative

To provide the surgeon with an optimal intraoperative milieu, a general anesthetic with endotracheal intubation and muscle relaxation is planned, and the patient will be positioned in steep reverse Trendelenburg to improve the surgical view. Incidentally, this improves diaphragmatic excursion and respiratory dynamics. Positioning and transferring devices for patient and staff safety are placed on the transporting stretcher in the preoperative phase. Transport stretchers and operating room (OR) tables must be appropriate for patient weight and mass distribution. Bariatric surgical tables are designed to safely accommodate and lift 340 to 450 kg (750 – 1,000 pounds). If one is unavailable, two regular (OR) tables may be secured together to achieve the same effect as a designated bariatric table.

A common misconception is that the patient's adipose tissue is an adequate cushion and prevents pressure injuries. The body habitus can obscure positioning mistakes and leave the patient vulnerable to entrapment injury, nerve damage, and rhabdomyolysis. Positioning devices may include a footboard or stirrups in the steep Trendelenburg or modified Lloyd–Davies positions. The extremities should be secured and padded in a neutral position. Shifting, compression, or overstretching can cause injury (eg, sprained or fractured ankles, sciatic or brachial plexus injury). Positioning can be done before induction of anesthesia to allow the patient to aid in positioning for comfort and safety. Muscle paralysis during anesthesia often masks painful positions that patients are not flexible enough to accommodate awake. Repeated checks during the procedure should be done to ensure they remain free from entrapment and undue pressure or stretch. Pre-induction airway preparation includes the patient being ramped with positioning cushions or blankets to provide optimal airway visualization with or without video laryngoscopy. These devices are removed after intubation to prevent brachial plexus stretch injuries. Alternatively, the patient bed may be placed in an approximately 25- to 40-degree reverse Trendelenburg position to decrease the compression of the lung structures and improve ventilatory mechanics as much as possible during preoxygenation when the patient is spontaneously breathing. Caution should be used when relying on reverse Trendelenburg alone to prepare for intubation, as this position may not compensate for other difficulties in the patient's airway. 

Not all obese patients have a difficult airway, but elevated BMI is associated with an increasingly difficult airway.[23]  Challenging airways may be due to redundant tissue within the airway, enlarged neck circumference, cervical fat pad impeding neck extension, or large faces that are more difficult to mask and ventilate using the 1- or 2-handed methods. Regardless of the expected difficulty, appropriate equipment and adequate preoxygenation increase the time to obtain the airway, given the rapid oxygen desaturation due to obesity-related changes in the respiratory system. If the first choice for intubation technique is direct laryngoscopy, then video laryngoscope, fiberoptic bronchoscope, and other advanced airway tools should be readily available. After preoxygenation, induction using a rapid sequence induction technique (RSI) or modified RSI may be chosen to decrease the apneic time before intubation and reduce the risk of potential aspiration. 

Ventilation in patients with increasing levels of obesity can be balanced between the surgeon's need for optimal visualization and using lung protective strategies to optimize oxygenation and decrease relative hypercapnia. In their guidelines for intraoperative mechanical ventilation for obese patients, the American Society of Anesthesiology (ASA) suggests using predicted body weight (PBW) when calculating for appropriate tidal volume (Vt) of 4 to 8 ml/kg. For males, PBW = 50 + 0.905[(height in cm) - 152.4] and in females PBW = 45.5 + 0.905[(height in cm) - 152.4].  High levels of positive end-expiratory pressure (PEEP) or peak inspiratory pressures and large tidal volumes should be avoided. Air entrapment or auto peeping should be avoided by allowing for adequate expiratory time. Recruitment maneuvers and increased levels of inspired oxygen can be used when desaturation or in situations where atelectasis may be worsened.[24][25][26]

Maintenance of general anesthesia can be achieved with inhalational agents, IV medications, or a combination of both. Anesthesia providers should consider the increased volume of distribution (Vd) when dosing medications in obese patients and drug lipophilicity. Increased Vd and the use of a lipophilic drug increase the half-life of elimination from a clinical standpoint. Many providers err on the side of caution of ideal body weight (IBW) or adjusted total body weight (ajBW) versus using total body weight (TBW) where ajBW = IBW + 0.4(TBW - IBW).[9] If using IBW or ajBW, there is room in dosing to titrate up to the effect required for more lipophilic drugs such as propofol. Total body weight dosing should be used for neuromuscular blockers (eg, succinylcholine and rocuronium), the neuromuscular reversal agent sugammadex, and opioids.[27] The use of a total intravenous anesthetic (TIVA) using propofol (typically 100-200 mcg/kg/min), in combination with opioids or as a solo agent, may also be considered as an option for general anesthesia when addressing concerns for PONV.

The volume of distribution and lipophilicity are also considered when choosing between inhaled agents such as isoflurane, sevoflurane, and desflurane. As the most lipophilic of the three, isoflurane requires a longer time to equilibrium and release when discontinued. Isoflurane is not often a drug of choice in this population. Sevoflurane is more lipophilic than desflurane and, in shorter cases, may allow patients to emerge more quickly, given the same amount of time for redistribution. However, given the duration of bariatric procedures and the larger Vd created by the increased adipose tissue, the emergence rates may not have a clinically significant difference.[28][29][30] 

There is relatively low insensible fluid and blood loss associated with most bariatric surgeries because of the laparoscopic or robotic approach. As such, various approaches to IV fluid management can be used. Goal-directed therapies use fluid bolus challenges and infusions to maintain hydration. They are guided by patient-ideal blood pressure and urine output or the measurement of stroke volume variation and pulse pressure variation by several commercial devices. Alternatively, the traditional 4/2/1 fluid replacement rule (4 mL x first 10 kg of total body weight + 2 mL x second 10 kg + 1 mL x each remaining kg of patient weight) may be used. Regardless of the choice, the ultimate goal is to keep the patient euvolemic by maintaining a urine output of 0.5 - 1 mL/kg/hr and decreasing the risk of postoperative renal dysfunction.[31][32]  ERAS protocols for bariatric surgeries recommend goal-directed fluid therapy but do not provide guidance on using colloid versus crystalloid to minimize the volume required to achieve these goals.[22]

Postinduction, an orogastric tube (OGT) may be placed to decompress the stomach and remove any stomach contents present. Depending on the surgery, the anesthesia provider may be required to pass orogastric tubes and staple anchoring devices for the procedure. During these manipulations, the endotracheal tube can be dislodged, either further in or out of the airway. Communication between all surgical and anesthesia team members is critical to ensure the OGT is removed to avoid suturing or retaining parts of the orogastric tubes or temperature probes.

Before emergence, the patient's pain, blood pressure, and hydration status should be optimized, and the patient fully reversed from neuromuscular blockade. IV opioids should be given judiciously to match the patient's respiratory rate and comfort level with caution to over-sedation and hypercapnia after extubation. ERAS protocols strongly endorse using opioid-sparing techniques with moderate to high levels of data and strength of clinical opinion. The patient's hemodynamic stability should be reassessed and addressed between the anesthesia provider and surgeon for any changes that might require an increase in the postoperative level of care.

In preparation for extubation, the patient is placed in an upright position, either seated or in a modified reverse Trendelenberg or 30- to 45-degree head-up position on the OR table to maximize spontaneous respiratory dynamics. The emergence location, bed or table, depends on how difficult the airway was to obtain and the degree of potential reintubation. Goals for extubation include the patient with respiratory rates of 12 to 18 breaths per minute and unassisted or minimally assisted and tidal volumes of 3 to 5 mL/kg. The inspired oxygen should show a tolerated incremental decrease during the weaning process before changing the support parameters stepwise. Any patient who appears to require an increased amount of respiratory support or has refractory hypoxemia that cannot be managed without aggressive intervention or shows a high likelihood of failure to maintain extubation should not be extubated. The patient should be reassessed for stability and status, and an alternative postoperative care plan, including an intensive care unit recovery, should be discussed with the surgeon. Airway supplies and medication for emergency reintubation should be readily available before extubation.[33][34]   

Postoperative

Once extubated and stable for transport, the patient is typically taken to the postoperative recovery unit (PACU) in the immediate postoperative period. Some level of pain or discomfort from the surgery is understandable. Anesthesia and opioids worsen baseline apneas and hypopneas in recognized and undiagnosed OSA patients. Routine oxygen supplementation may mask these apneas and hypopneas. If required, continuous positive airway pressure (CPAP) or other noninvasive oxygen supplementation, such as high-flow oxygen by nasal cannula, should be readied in the PACU. Both can provide necessary levels of CPAP with a relatively low risk of dehiscence of suture lines.[35]  Patients suspected of OSA have similar levels of postoperative adverse respiratory events compared to patients with a diagnosis of OSA, but those events are likely to be more severe.[7]  Respiratory status monitoring should proceed for at least 1 hour postoperatively.[36]  ERAS protocols also support supplementary oxygen as needed and noninvasive respiratory support regardless of an OSA diagnosis.[37]

In addition to preoperative multimodal pain management, pain control with IV opioids is administered as needed in the recovery phase. Transition to a patient-controlled analgesia (PCA) pump or oral analgesics may be necessary. Caution should be used when adding a continuous underlying infusion to a PCA pump in patients with known or suspected OSA. PCA pumps should be discontinued if the patient appears to have a pain-sedation mismatch (somnolent and difficult to arouse, respiratory depression signs, and then describing intense pain when able to be awakened). The patient should be reevaluated for changes in postoperative status. Once surgical sources for new pain have been ruled out, the need for noninvasive or increased respiratory support should be addressed.

High or low blood glucose levels, poorly controlled hypertension, and low volume or dark-colored urine should be addressed in the PACU. PACU staff must promptly inform the anesthesia and surgical teams if any issues with breathing, pain management, or worries about complications like rhabdomyolysis or nerve damage arise. An increase in the level of care and interventions may be required at the time of discharge from the unit. This assessment and discussion should be an opportunity to maximize a critical juncture in the patient's care to give them the best chance at an optimal and speedy recovery.

Long-Term Postoperative Concerns

Long-term, postbariatric surgery patients may return for other procedures, including further evaluation of progress or for surgeries to modify their prior bariatric surgeries. Over time, some patients may experience a resurgence of weight gain, surgical complications, or desire removal of excess skin and tissue following significant weight loss. In the case of re-operative bariatric surgery, there are no clear guidelines and currently limited data to support it. The goal is often to maintain or improve weight loss or diabetic management.[38][39]  Preanesthetically, patients should be reevaluated regarding their physical status, medication regimen, and functionality changes. 

If some gastrointestinal obstruction is suspected, a baseline chest x-ray and vital signs should be obtained to evaluate for microaspirations versus frank aspiration risk. Depending on clinical presentation, patients may require rapid sequence inductions to reduce the risk of aspiration. Nasogastric and orogastric tubes for suction should be avoided unless necessary. If they are to be placed, they should be under direct visualization due to the high risk of perforation and misplacement and after discussion with the attendant surgeon. Vomiting and chronic nausea from postoperative changes may require alternative approaches to recovery room care and discharge instructions, including education on when to return for further care if the patient cannot remain hydrated.

After recognizing the opioid pandemic occurring in the early to mid-2000s, physicians have begun reevaluating the risk of opioid use in patients. In postoperative patients considered opioid naive, there is a 5.9% to 6.5% increased rate of new and persistent opioid use, regardless of the type of surgery. Given that the bariatric surgery patient population has an elevated prevalence of chronic noncancer pain and opioid use, there is concern that opioid use may continue and may worsen after bariatric surgery. Multimodal pain control is important throughout the perioperative period. In addition to the ERAS protocols for multimodal pain control, the Metabolic and Bariatric Surgical Accreditation and Quality Improvement Program (MBSAQIP) from the American College of Surgeons has also introduced a program to address the risk of opioid abuse after bariatric surgery (BSTOP). BSTOP suggestions correspond with ERAS protocol and provide additional support to surgeons in limiting postoperative opioid prescriptions.   The Substance Use–Disorder Prevention that Promotes Opioid Recovery and Treatment for Patients and Communities (SUPPORT) Act decreases the liability that surgeons may suffer from legal claims regarding patient satisfaction regarding pain. A 2023 meta-analysis of the combination of ERAS and BSTOP implementation shows an overall "reduced length of hospital stay and opioid use at discharge."[40][41]

Clinical Significance

Effective communication among interdisciplinary teams is crucial for successfully treating bariatric patients. This requires a coordinated effort involving surgeons, anesthesiologists, nurses, pharmacists, and respiratory and physical therapy specialists. The role of the anesthesia provider is particularly significant during the immediate perioperative phase. Preoperative guidelines are designed to ensure that bariatric surgery patients are in the best possible physical condition, considering their obesity-related health issues.

Educating patients before the procedure is critical to gaining their cooperation in using multimodal, low-opioid pain management strategies. This education helps set realistic expectations about some postoperative pain while outlining various methods to manage it effectively. The implementation of protocols to reduce opioids and postoperative nausea and vomiting (PONV), as recommended by the ERAS society, necessitates alignment between nursing care and anesthetic plans for optimal outcomes. While most adjunct intravenous infusions provide temporary pain relief during and shortly after administration and are linked to reduced opioid usage, their effectiveness depends on a comprehensive approach. This approach begins with patient education and extends through the entire surgical experience. The benefits of a low-opioid strategy during surgery are diminished if the patient starts receiving high doses of opioids after leaving the recovery room.

Regardless of protocols, each patient is an individual; therefore, each anesthetic must be tailored to the patient and the events that belong to that patient's surgery. Communication of patient reaction and sensitivity to pain, medication, and effort is paramount when handing over care in the recovery room. Engagement at the human level regarding the patient's preoperative presentation and interactions also helps guide nursing care to smooth the transition through the recovery room and beyond.

Overall, the challenge of planning successful anesthetics for patients undergoing bariatric surgery can be rewarding and engaging. The patient population is eager for their procedures, engaged in their health, and excited to move through a new phase. Anesthesia providers are crucial in the treatment and interdisciplinary communication during the perioperative period. Anesthesia providers should proactively assess, plan, and treat this patient population during the immediate perioperative period.

Enhancing Healthcare Team Outcomes

Bariatric surgery to reduce obesity and impact obesity comorbid conditions has become safer over the past half-century as bariatric surgical societies have utilized the multidisciplinary healthcare team approach. Guidelines from the American Society for Metabolic and Bariatric Surgery, in combination with the International Federation of Surgery for Obesity (ASMBS/IFSO), were most recently updated in 2022. 

ERAS protocols encourage nurses and dietitians to educate patients regarding dietary and lifestyle adjustments, physical therapy, and physiotherapists to guide prehabilitation and physical fitness. Level II, III, and IV data suggest that while it may not improve morbidity, it positively impacts physical mobility at least six months after surgery. Anesthesia care team members are instrumental in providing balanced anesthetics that decrease the risk for PONV and emphasize multimodal pain control. Anesthesia providers are also helpful in continuing communication between patients, surgeons, nurses, and respiratory therapists regarding the likelihood and early treatment for airway obstruction. \Surgeons decrease the risk of infection and improve mobilization time by reducing drain placements and nasogastric tube use for decompression. Nurses, pharmacists, and therapists identify social factors in the postoperative period that may improve opioid use in this high-risk patient population. 

Bariatric surgery is still not without risk and requires a "whole team" approach to improve patient outcomes successfully.

Nursing, Allied Health, and Interprofessional Team Interventions

Obesity, as a disease, can have a multifactorial set of causes that do not respond to one treatment alone. As such, bariatric surgery is not meant to be a stand-alone "silver bullet" for treating obesity. The American Society for Metabolic and Bariatric Surgery, in combination with the International Federation of Surgery for Obesity (ASMBS/IFSO), has supported and introduced updated guidelines for preoperative preparation to optimize patients' success in maintaining weight loss long term.

It is a multidisciplinary approach focusing on the patient's overall health and decreasing wound infections and patient anxiety regarding the procedure. Patients typically self-select for bariatric procedures. Once they have engaged with a surgeon, the patient will participate in educational interventions with nurses, dietitians, social workers, or psychologists about

• Pre-exercise, healthy lifestyle, and dietary choices. Some programs encourage a low-calorie weight loss regimen for several weeks before surgery, driven by insurance companies ostensibly as proof of the future efficacy of bariatric surgery.
• A history or presence of alcohol use disorder. The patient should be in documented recovery for at least 1 to 2 years.
• Smoking history, with at least four weeks or more of cessation before the procedure.

The goal for patients is to understand the process of living with the postoperative changes they seek and successfully implement these changes. Most of the interventions suggested have strong recommendations by the ASMBS/IFSO and ERAS societies. However, the data for the specific outcomes are questionable. Problems arise because some initial data has been extrapolated from other gastrointestinal surgeries, such as those resulting from colorectal surgery for cancer treatment. Most outcomes studied were for hard targets of postoperative physical change rather than softer targets showing the life-long change in patient behavior. Regardless of the data, multidisciplinary team interventions that treat the patient holistically can create long-lasting, effective outcomes by evaluating and managing factors that can be changed to reduce the risk of perioperative complications and improve outcomes.

Nursing, Allied Health, and Interprofessional Team Monitoring

Obese patients undergoing bariatric surgery are at an increased risk of respiratory depression in the postoperative period. Communication of individual patient responses to all care team members must be made clearly and thoroughly. Pain-sedation mismatch (somnolence, difficulty to arouse, signs of respiratory depression but describes intense pain when awakened) is a crucial identifier of not only increased risk for airway obstruction but of pain management requirements throughout the pre-discharge period of recovery. 

An increased level of monitoring may be needed throughout the patient's hospital stay. Discussion between the anesthesia care team, surgeon, nurse, and respiratory therapist can decrease the risk for adverse respiratory events in the first days after surgery. In the immediate postoperative phase, the monitoring and interventions may require a more extended stay in the PACU for an hour or more to identify the level of monitoring and intervention needed. Monitoring may decrease as the patient progresses and improved sleep architecture begins to reassert. All healthcare team members are empowered to speak on behalf of their observations to impact the patient's care and further improve their long-term success and outcome.