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CON: Supraglottic airway devices: Safety concerns in laparoscopic surgery

May 2, 2023

Sabastian Omenyo, MD; Laura V. Duggan, MD, FRCPC

This article is part of a pro-con debate on the use of supraglottic airway devices in laparoscopic surgery. The “pro” was published in our February 2023 newsletter at Supraglottic Airway Devices (SADs) and Laparoscopic Surgery.

Introduction

Laparoscopic SurgeryIn 1986, Sir Archie Brain patented the Laryngeal Mask Airway (LMA©).1 Four decades later, supraglottic airway devices (SADs) have evolved to include esophageal ports (called second-generation devices) and changed angulation to facilitate tracheal intubation. SADs can be an effective alternative to tracheal intubation during general anesthesia and an indispensable adjunct in unexpected difficult airway management. Although SAD use is common in anesthesia, their use has not been universally adopted for laparoscopic surgery. Concerns include the potential risk of gastroesophageal regurgitation leading to aspiration. Problems achieving effective ventilation can also occur due to the combined influences of pneumoperitoneum and postural changes restricting respiratory mechanics in the setting of increased carbon dioxide burden. Despite 40-years of history, SAD use in laparoscopic surgery remains a controversial topic.

Pulmonary aspiration

Pulmonary aspiration of gastric contents is one of the most concerning and life-threatening complications in anesthesiology. Fortunately, its frequency is quite low; of the 2,496 ASA Closed Claims cases collected from 2000-2014, only 115 (5%) were aspiration claims.2 However, when pulmonary aspiration did occur, it resulted in a high fatality rate. Of these 115 patients, death occurred in 57% (n=66) directly as a result of the aspiration event. Notably, 55% (n=63) of aspiration events occurred during elective surgery.

Given the potential life-threatening nature of aspiration, aspiration risk with SAD use for laparoscopic surgery must be equivalent to, if not less than, the risk associated with tracheal intubation. Tracheal intubation with a cuffed endotracheal tube safeguards the trachea from aspiration by strictly isolating it from regurgitating matter. In contrast, SADs equipped with esophageal ports to redirect gastric contents away from the trachea may not be effective in preventing aspiration depending on the quantity and nature of the regurgitated matter.

Currently there are no adequately powered randomized trials comparing SAD use to tracheal intubation in elective patients presenting for laparoscopic surgery with the primary outcome of clinical aspiration; and there probably never will be. The frequency of aspiration leading to death or significant patient harm is so low that thousands of patients would be required. Therefore, we are left with closed claims, retrospective observational studies, and reasoned opinion to assess the safety of SGAs compared to tracheal intubation.

Delayed gastric emptying (gastroparesis) may increase both liquid and solid gastric contents and may eventually lead to increased intragastric pressure. Medications (e.g. prednisone, opioids, levodopa) and physiologic stresses (e.g. trauma, sepsis, pain) are known to decrease gastric motility.3 Can we assume that elective surgical patients with no risk factors for delayed gastric emptying who have adhered to fasting guidelines, have empty stomachs? In a sobering 2017 study of 538 fasted patients presenting for elective surgery, preoperative gastric ultrasound found 1.7% patients had solid gastric matter and 4.5% had ≥1.5 ml/kg of gastric fluid. Of the 32 patients with solid gastric matter, only six (19%) had documented risk factors for delayed gastric emptying.4 In a 2020 of 138 fasted patients presenting for elective laparoscopic cholecystectomy (essentially the patient population we are debating) 12 (9%) had solid gastric matter with an additional 6 (4%) having ≥1.5ml/kg of gastric fluid.5 As the accompanying editorial stated, we may trust we can identify which patients are at risk for aspiration, but we should not.6

Contextual issues associated with laparoscopic surgery; Practical aspects of managing urgent conversion to tracheal intubation

Most laparoscopic procedures require some modification in patient positioning. Such positioning changes can result in misplacement of a previously well-seated, effective SAD. From a practical perspective, laparoscopic procedures are often performed in a darkened operating room, with Trendelenburg or reverse-Trendelenburg positioning often with the patient’s head obscured by surgical drapes. Simultaneously, pneumoperitoneum both increases carbon dioxide load (and ventilation requirements) while restricting diaphragmatic movement. Managing such challenges requires the capacity to increase minute ventilation safely and effectively. If the maximum positive pressure limits of the specific SAD being used are breached, ineffective ventilation and gastric insufflation result.

Under such circumstances, the SAD may require urgent conversion to tracheal intubation. Multiple steps are involved which require precise team communication to maintain patient safety. There is a paucity of published evidence regarding the safe intraoperative conversion from SAD to tracheal intubation, or how frequently it occurs. If such an airway emergency occurs, several steps can optimize conditions: turning on the room lights, calling for assistance, patient repositioning, removal of laparoscopic instruments, and de-sufflation of the abdomen. Head and neck swelling can occur during prolonged Trendelenburg positioning potentially making tracheal intubation more difficult. Patient harm may result if the need to convert from SGA to tracheal intubation occurs during a critical surgical period (e.g., achieving control of bleeding vessels). This can be prevented by tracheal intubation under more controlled circumstances from the outset.

Conclusion

Even if a thorough preoperative assessment is performed, current ultrasound evidence shows a small percentage of elective patients may have gastric solid or significant liquid stomach contents despite adhering to preoperative fasting guidelines. This concern in addition to patient positioning, obesity, and other common comorbidities can result in delayed gastric emptying and decreased lower esophageal barrier pressure, both of which increase the potential risk of aspiration. SADs are not a singular device; airway managers must have knowledge of the oropharyngeal leak pressure of each SAD they use (available in the manufacturers’ instructions for use). Context is essential when deciding which airway device should be used as conversion to tracheal intubation can be challenging and potentially harmful to the patient during critical surgical times. SADs have revolutionized airway management over the last four decades; given the current evidence, the safety of its widespread use in laparoscopic surgery remains unknown. Therefore, given the current evidence, the widespread adoption of SADs for laparoscopic procedures is not supported.

 

Sabastian Omenyo, MD is an Anesthesia Resident in the Department of Anesthesiology and Pain Medicine at the University of Ottawa, Ottawa, Ontario, Canada.

Laura V. Duggan, MD MSc (Clin Epi) FRCPC is an Associate Professor of Anesthesiology in the Department of Anesthesiology and Pain Medicine at the University of Ottawa, Ottawa, Ontario, Canada.

The authors have no conflicts of interest.

References

  1. Dr. Archie Brain: The Laryngeal Mask [Internet]. Dr. Archie Brain: Association of Anaesthetists of Great Britain and Ireland Heritage Centre. [cited 2023 Apr 20]. Available from: https://anaesthetists.org/Home/Heritage-centre/Collection/Oral-Histories/Dr-Archie-Brain-The-Laryngeal-Mask
  2. Warner MA, Meyerhoff KL, Warner ME, Posner KL, Stephens L, Domino KB. Pulmonary Aspiration of Gastric Contents: A Closed Claims Analysis. Anesthesiology. 2021 Aug 1;135(2):284–91.
  3. Camilleri, M. Gastroparesis: Etiology, clinical manifestations and diagnosis [Internet]. 2023 Mar [cited 2023 Apr 15]. Available from: https://www.uptodate.com/contents/gastroparesis-etiology-clinical-manifestations-and-diagnosis?search=drugs%20delay%20gastric%20emptying&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
  4. Van De Putte P, Vernieuwe L, Jerjir A, Verschueren L, Tacken M, Perlas A. When fasted is not empty: a retrospective cohort study of gastric content in fasted surgical patients. British Journal of Anaesthesia. 2017 Mar;118(3):363–71.
  5. Chang JE, Kim H, Won D, Lee JM, Jung JY, Min SW, et al. Ultrasound assessment of gastric content in fasted patients before elective laparoscopic cholecystectomy: a prospective observational single-cohort study. Can J Anesth/J Can Anesth. 2020 Jul;67(7):810–6.
  6. Schwarz SKW, Prabhakar C. What to do when perioperative point-of-care ultrasound shows evidence of a full stomach despite fasting? Can J Anesth/J Can Anesth. 2020 Jul;67(7):798–805.