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Confidently caring for critically ill overweight and obese adults

Pritts, Wanda MSN, RN, CNS, CCRN, CEN

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doi: 10.1097/01.CCN.0000612872.24708.cb
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Every day, nurses face the challenge of confidently and safely delivering high-quality compassionate care to patients who are overweight or obese. The World Health Organization reports worldwide obesity has tripled since 1975 with 40% of the population now considered obese.1,2 It is estimated that 1 in 10 patients admitted to the hospital and 26% of critical care patients are Class 3, or extremely obese.2-4 The critical care nurse is uniquely situated to assess the multifaceted needs of this patient population.

Care challenges

The obese patient is complex and highly susceptible to complications. Overweight and obesity are defined as abnormal or excessive fat accumulation that impairs health.5 Body mass index (BMI) is a measure of weight adjusted for height, calculated as weight in kilograms divided by the square of height in meters (kg/m2).6 BMI is commonly used to classify overweight and obesity. The BMI calculation has limitations, primarily measuring excess weight as opposed to excess body fat. It may overestimate body fat in patients with a muscular build or underestimate body fat in older patients who have lost muscle. Despite the limitations it remains the primary method of classifying obesity as other more-sensitive methods of determining obesity have practical limitations in the critical care environment.7-9 (See BMI classifications and associated disease risk.)

The word “bariatric” comes from the Greek root “baros,” meaning large or heavy. Bariatrics refers to the management of patients with extreme obesity (BMI greater than 40) and its related diseases.10 Although BMI is a practical tool, each patient is unique and obesity is a continuum; no chart can predict what health consequences a patient will experience at a particular weight. Instead, the nurse must be familiar with obesity's many potential impacts and individualize the patient's care.

Regardless of the admitting diagnosis, three in four bariatric patients have at least one comorbidity.5,9,11 Adipose tissue is proinflammatory, leading to a chronic proinflammatory hypercoagulable state.12-16 (See Common comorbidities in patients with overweight or obesity.)

Bariatric patients experience a disproportionately elevated rate of harm events in comparison to patients of normal BMI.11,17,21,23,24 The impact of obesity can be seen across the spectrum of critical illness. When preparing to confidently deliver high-quality care, be aware that the patient's greatest vulnerabilities are related to ventilation, tissue perfusion, pharmacokinetics, and mobility.11,17,21,23-25

High-quality care will require a multidisciplinary approach and collaboration between: the care team (nursing, respiratory care, wound care, pharmacy, physical therapy, dietary, case management, and providers—primary and specialists); the facility (resource commitment of appropriately sized equipment including lifts and assistive devices); and the patient, as able.

Table BMI
Table BMI:
classifications and associated disease risk8

Bias and discrimination are significant potential barriers to high-quality care. Weight bias is the fourth most-reported form of discrimination.26 Multiple studies document significant weight bias by healthcare providers.23,26-29 Subjecting patients with obesity to poor treatment, insensitive or unkind comments, shaming or prejudice is never appropriate.26 Discrimination prevention begins with individual self-reflection on attitudes and biases and education on obesity as a multifactorial and complex medical disorder.23,26,28 Word choice is important when communicating with a bariatric patient. Do not shame a patient by using degrading terms, such as “big-boy beds” or “elephant cuffs”; instead, choose nonjudgmental terms, such as “expanded capacity furniture” or “appropriately sized cuff.” All patients deserve compassion, respect, and kindness.

Ventilation

The critical care nurse must have a sound grasp of the physiologic impact of obesity. Each patient presents with different concerns related to weight, body habitus, and comorbidities. The greatest vulnerability is related to oxygenation and ventilation. Adipose tissue in the neck, thorax, and abdomen affect respiratory mechanics, gas exchange, and ventilatory control.18,19 The bariatric patient is four times more likely to experience respiratory failure than the average patient.18,19,23,30 A triad of potential difficulty is formed by changes in the structure of the pharynx and neck, increased chest wall mass and circulating blood volume, and increased intraabdominal pressure.11,18,19,21,23,24

First, bariatric patients have an increased tongue size, redundant pharyngeal tissue, increased neck circumference, and limited neck mobility. The result is increased upper airway resistance.11,18,21,23,24 It may be difficult to properly fit a bag-valve-mask and ventilate the patient. Intubation may be challenging if landmarks are poorly visualized. If tracheostomy is required, specialized longer tubes must be available. This patient is extremely susceptible to hypoxemia during intubation.11,18,23,24

Second, the bariatric patient has increased chest wall mass and circulating pulmonary blood volume. This decreases tidal volume, which necessitates an increased respiratory rate, resulting in a higher oxygen requirement to do the work of breathing itself.4,18,19,21,24

Third, increased intra-abdominal pressure limits diaphragmatic excursion in this patient population. The increased pressure on the diaphragm increases the difficulty in effectively ventilating the patient. Appropriate positioning is critical to effective ventilation.4,18,19,21,24

To manage this triad of pulmonary issues the critical care nurse must assess, plan, and intervene confidently. Pulse oximetry may be unreliable secondary to increased finger tissue thickness and poorly transmitted light waves. The ear lobe is a better choice for monitoring SpO2. Positioning should include not only elevating the head of the bed, but also placing the entire bed into reverse Trendelenburg position to shift the weight of the abdomen off the diaphragm.11,23 Preplan strategies to manage a difficult airway. The American Society of Anesthesia guidelines for airway management of the bariatric patient recommend building a “B.I.G.R.A.M.P.” (See Bariatric airway management.)

The “ramp position” elevates the upper body and head until the external auditory meatus is level to the sternal notch. It is then combined with reverse Trendelenburg to shift weight of the chest wall inferiorly and improve diaphragmatic excursion. Apneic oxygenation has been demonstrated to decrease hypoxemia during intubation. Expect lung-protective ventilation strategies including low tidal volumes 5-7 mL/kg of Ideal Body Weight, moderate to high PEEP, and recruitment maneuvers to reopen collapsed alveoli.4,11,23,31,33 If neuromuscular blockade is used, the nurse must take care to prevent unintentional awareness as there is rapid redistribution of sedatives into adipose tissue.34 Failure to wean and need for tracheostomy require planning. Specialty-sized tracheostomy tubes may need to be ordered. Tracheostomy placement is complex depending on the patient's anatomy and will often be done in the OR. Coordinate with the OR regarding potential need for attachments and/or extensions for the OR table.

Table
Table:
Common comorbidities in patients with overweight or obesity11,17-22

Tissue perfusion

Patients with Class 3 obesity may experience significant alterations in hemodynamics.20,35 An increased circulating blood volume makes these patients susceptible to inadequate fluid resuscitation. Left ventricular hypertrophy develops secondary to increased myocardial workload and may lead to heart failure, particularly if the patient has preexisting hypertension.17,19,21,30 Simple interventions and monitoring present challenges. Peripheral venous access is difficult; the standard catheter may not be adequate and a 3- to 4-in catheter may be needed. Use of adjuncts such as ultrasound-guided placement or a peripherally inserted central catheter should be considered. Although central venous access is frequently needed, it is challenging if anatomical landmarks are difficult to locate. Additional personnel are needed to manage adipose tissue during insertion. Care must be taken to monitor respiratory status closely during insertions, especially with the patient under sterile drapes.23,36 Placement of femoral central venous catheters increases the risk of infection but may be unavoidable.23,30,35 Accurate BP monitoring may require an arterial line. This is highly recommended for vasoactive drug titration.

Table
Table:
Bariatric airway management19,23,31,32

Fitting a BP cuff is problematic. If the patient's upper arm is shaped like an inverse cone, a cylindrical cuff will not fit. In this situation, place the cuff lower on the upper extremity and be consistent in location and size.19,23,30

Atrial fibrillation is common and requires rate control, anticoagulation, and potentially inotropic support.17,20,23 Obesity is associated with hypercoagulability related to the inflammatory nature of adipose tissue. Obesity, with impaired mobility, decreased venous velocity, and impaired venous return, is an independent risk factor for the development of venous thromboembolism (VTE). Aggressive VTE prophylaxis is required.20,21,23,30

Neurologically, it is important to maintain cerebral perfusion pressure. This requires accurate assessment of BP, which may necessitate the placement of an arterial line. Appropriate positioning of the patient's head and neck to support the airway will also facilitate venous drainage and help preserve cerebral perfusion.

Pharmacotherapy

Bariatric patients have altered pharmacokinetics related to volume distribution, impaired renal clearance, hepatic metabolism and protein binding, increased adipose tissue, and increased capillary permeability.23,30,37 This frequently results in patients being both under- and overdosed and experiencing antibiotic treatment failure.17,21,30 Consultation is required to guide therapy related to the use of ideal body weight or total body weight for dosing. In general, highly lipophilic medications (etomidate, succinylcholine, fentanyl, and midazolam) distribute into the peripheral adipose tissue resulting in less active medication effect and should be dosed on total body weight. Lipophilic medications will need higher bolus doses because of the increased amount of adipose tissue. In contrast, when a medication is hydrophilic (propofol, rocuronium, and vecuronium), the volume of distribution is lower and the dose should be based on ideal body weight. If there is a narrow treatment range, the medications will require very close monitoring and titration. The bariatric patient is most vulnerable with cardiovascular, sedative, antimicrobial, and anticoagulant medications.19,23,30,37

Control of hyperglycemia is appropriate. Diabetes is a common comorbidity and labs such as A1C help the nurse evaluate how effectively the patient has managed the disease and how best to support and teach them.21,36

The bariatric patient has an increased renal blood flow and glomerular filtration rate. This may lead to increased renal clearance of medications. There is a high rate of undiagnosed chronic renal failure in the bariatric population.37 Critical illness may evoke acute kidney injury in the setting of chronic kidney disease. Multidisciplinary collaboration between the primary physician, renal consultant, and pharmacist is needed.21,23,36,37

The impact of obesity on the gastrointestinal system varies greatly with each patient. Consultation and guidance by nutritional support staff is valuable. It is common for the bariatric patient to have preexisting dietary deficiencies. These patients are prone to develop protein malnutrition as a result of the metabolic stress of critical illness.18,21,23 A hypocaloric high-protein regimen is recommended with enteral nutritional support beginning within 24 to 48 hours. It is extremely important that no nasogastric or oral gastric tube be placed blindly if the patient has a history of bariatric surgery. Patients who have had bariatric surgery, such as gastric bypass (the stomach converted to a small 30 mL gastric pouch), gastric sleeve (80% to 90% of the stomach removed), or gastric banding (creation of a very small pouch with small opening to stomach), could suffer significant trauma if gastric tubes are placed incorrectly. Nasogastric tubes should be placed using radiographic guidance.30,38 If there is no history of bariatric surgery, bedside insertion is appropriate. Once tubes are placed at bedside, radiographic verification may be challenging related to the patient's size. Filling the lumen of the tube with contrast prior to radiograph may facilitate assessment of placement. Nutritional support and supplements aimed at supporting skin integrity are recommended.25 Aspiration risk is markedly increased for this patient population related to higher gastric volumes, lower acidity, and decreased esophageal sphincter tone. Head of bed up with reverse Trendelenburg positioning will help prevent aspiration.4,31,32 If the patient has a history of gastric bypass surgery, it is imperative they do not receive liquids or foods with a high sugar content to avoid triggering an episode of dumping syndrome.21,23,30,36

Musculoskeletal and integumentary issues present significant challenges. Chronic pain syndromes are common if excess weight has caused breakdown of joints resulting in chronic back, hip, knee, and ankle pain. Osteoarthritis and gout are also common comorbidities.21,22,39 Multimodal pain management is recommended considering the patient's previous medication regime and tolerance. When employing opioids, use small doses titrated to effect while vigilantly assessing the patient's airway, SpO2, end-tidal CO2, sedation level, and work of breathing.21,23,36,37

Mobility

Challenges of safe patient handling present a potential barrier to effective collaborative care. Safe mobilization is foundational in prevention of harm events and a central concern for both the patient and staff. Adaptations are required to provide care in a way that maintains patient dignity, ensures patient safety and prevents injury to the staff. Healthcare workers experience more than twice the work-related injuries of other industries.23,35 Avoid manually lifting the bariatric patient for the safety of both the patient and the staff.23,40 Friction-reducing devices and air-assisted systems that can be left under the patient significantly increase safety for both the patient and staff.40,41

The bariatric patient is four times more likely to develop a pressure injury than the average patient.3,25 Cellulitis is both a common reason for admission and a complication of admission.3,25 Venous stasis increases the risk of developing VTE. Impaired skin integrity is a significant issue related to the impact of the disease state, comorbidities, and the stresses of critical illness. Collaboration with wound care services is recommended if available.25 First, do no harm. Control moisture, particularly in deep folds under pendulous breasts, groin folds, or under the pannus. Areas should be kept as dry as possible using moisture-wicking fabric and fungus-inhibiting powders. Avoid using more than 2 to 3 layers of linen, which will accelerate skin breakdown.25 Pressure relief surfaces and frequent safe repositioning are required. Repositioning is a high-risk activity for both patient and staff. Use lifts or air-assist technology, which decreases the patient weight load to 10% of actual weight, whenever positioning.3,21,25,30,36

Unique challenges are present for what are usually routine diagnostic procedures. When imaging is required, the nurse must assess several issues. First, safety begins with clear communication of safe weight capacity and limits for each diagnostic modality such as the CT scanner or MRI table. Assess if the patient will safely fit on the table. Each patient's body habitus is unique and must be individually assessed. Weight and size restrictions must be assessed prior to transport, as well as alternative imaging locations. Even when the patient safely fits, some imaging studies may not be of adequate quality to be diagnostic.24,30,36

Conclusion

The bariatric patient in the critical care and progressive care areas is uniquely vulnerable. No number on a scale can dictate the appropriate care for the patient, instead the nurse must be armed with knowledge and strategies to assess and intervene for each patient's unique actual and potential needs. Understanding the possible physiologic alterations and complications of obesity prepares the critical care nurse to plan for and provide excellent care in a dignified professional manner that keeps both the patient and staff members safe. Critical care nurses are uniquely situated to advocate for and provide high-quality, safe, compassionate care to the bariatric patient.17,19,23,30,36

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        Keywords:

        bariatric; BMI; comorbidities; discrimination; mobility; obesity; overweight; pharmacokinetics; tissue perfusion; ventilation; weight bias

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