With the increasing prevalence of obesity in the United States, it is important to be aware of the complications associated with obesity, surgery, and airway management [1]. Obesity can negatively affect lung anatomy and the ability of the lungs to expand and take in oxygen. Thus, bariatric patients often experience increased atelectasis – the collapsing of part or all of the lungs [2]. Obesity is also a major risk factor for obstructive apnea syndrome which predisposes patients to complicated respiratory care. This includes difficult mask ventilation, difficult intubation, and often obstruction of the upper airway [2]. A combination of obesity and obstructive sleep apnea can impair tracheal intubation, with a 15-20% incidence of difficult intubation, versus 2-5% in the general population [6]. Optimizing oxygenation and airway management in bariatric patients undergoing surgery requires a unique approach, especially those with obstructive sleep apnea.
In bariatric patients, non-invasive respiratory management may assist with airway management, in particular by decreasing risk of atelectasis. One method is to use high positive end-expiratory pressure (PEEP) ventilation during pre-oxygenation, before a patient is intubated for surgery. This can be done using a continuous positive airway pressure (CPAP) machine or a non-invasive ventilation mask (NIV). Using PEEP is associated with reduced atelectasis formation and improved oxygenation [4]. Positioning is another method to improve oxygenation prior to mechanical ventilation. Optimizing respiratory function by having the patient in a sitting position during pre-oxygenation can decrease rates of atelectasis formation and oxygen desaturation [2, 5]. Once the operation begins, rapid sequence induction (RSI) is initiated, where the NIV mask is removed and intubation of the patient occurs immediately. During intubation, the patient does not receive supplemental oxygen, and breathing is paused. Administering high-flow oxygen during the preoxygenation and apneic periods is important for extending how long apnea can occur without high risk to the patient [2].
During surgery, patients are in supine position or laying on their backs under general anesthesia. General anesthesia along with the supine positioning can induce atelectasis formation. This can lead to a lack of adequate oxygen intake during intraoperative mechanical ventilation. Studies have found that the rate of atelectasis formation from general anesthesia was much higher in obese patients than non-obese patients [2,3]. Further, atelectasis can persist after extubation. In one study, atelectasis remained unchanged for at least 24 hours in patients who were morbidly obese, whereas in nonobese patients, atelectasis spontaneously resolved [3]. Obese patients are also at high risk of post-extubation stridor, or a high-pitched breathing sound that is a sign of airway obstruction or tracheal injury [2]. In order to avoid stridor, cuff-leak tests, where the cuff of the tracheal tube is deflated to measure an air leak, can be done intermittently. If suspecting stridor, prophylactic IV steroids can be given four hours before extubation [7]. Overall, it is important to take precautions and use evidence-based techniques to improve airway management during intubation, ventilation, and extubation of bariatric patients. This can help to further prevent complications and morbidities post-operatively as well as improve outcomes in this patient population.
References
- Montravers, Philippe, et al. “What’s New in Postoperative Intensive Care after Bariatric Surgery?” Intensive Care Medicine, vol. 41, no. 6, 12 Feb. 2015, pp. 1114–1117, 10.1007/s00134-015-3686-4.
- De Jong, Audrey, et al. “Mechanical Ventilation in Obese ICU Patients: From Intubation to Extubation.” Critical Care, vol. 21, no. 1, 21 Mar. 2017, 10.1186/s13054-017-1641-1.
- Eichenberger, A.- S., et al. “Morbid Obesity and Postoperative Pulmonary Atelectasis: An Underestimated Problem.” Anesthesia & Analgesia, vol. 95, no. 6, Dec. 2002, pp. 1788–1792, 10.1097/00000539-200212000-00060.
- Gander, Sylvain, et al. “Positive End-Expiratory Pressure during Induction of General Anesthesia Increases Duration of Nonhypoxic Apnea in Morbidly Obese Patients.” Anesthesia & Analgesia, vol. 100, no. 2, Feb. 2005, pp. 580–584, 10.1213/01.ane.0000143339.40385.1b.
- Naimark, A., and R. M. Cherniack. “Compliance of the Respiratory System and Its Components in Health and Obesity.” Journal of Applied Physiology, vol. 15, no. 3, 1 May 1960, pp. 377–382, 10.1152/jappl.1960.15.3.377.
- Siyam, Mohammad A., and Dan Benhamou. “Difficult Endotracheal Intubation in Patients with Sleep Apnea Syndrome.” Anesthesia & Analgesia, vol. 95, no. 4, Oct. 2002, pp. 1098–1102, 10.1097/00000539-200210000-00058.
- Jaber, Samir, et al. “Post-Extubation Stridor in Intensive Care Unit Patients.” Intensive Care Medicine, vol. 29, no. 1, Jan. 2003, pp. 69–74, 10.1007/s00134-002-1563-4.
