Pulmonary Complications in Endoscopic Skull Base Surgery: A Prospective Study

Background: Silent aspiration of orogastric secretions, blood and irrigation fluid during surgery may predispose to postoperative pulmonary complications (POPC) and may be increased during surgeries that involve the upper airway such as endoscopic endonasal surgery (EES) of the skull base. Our prior retrospective study found the incidence of POPC in skull base surgery to be around 30%. POPC was associated with age >65, surgery and intubation duration, estimated blood loss (EBL), and postoperative intubation status.

Objectives: This prospective study aimed to better characterize intraoperative factors that may contribute to silent aspiration and subsequent development of POPC in patients who underwent EES.

Methods: This is a prospective analysis of 86 patients who underwent EES from August 2023 to July 2024. Each surgery was randomly selected and intraoperative variables (volume of irrigation, EBL, endotracheal tube [ETT] size and cuff pressures, and gastric tube use during surgery), were recorded. Additional data included body mass index (BMI), surgery duration, intubation duration, respiratory status after surgery, intraoperative and postoperative cerebrospinal fluid leak (CSF), length of hospital stay, and preoperative history of pulmonary disease. Descriptive statistics were used to summarize the demographics of the patient population. P <0.05 was considered statistically significant. Chi-square for independent tests and Fischer’s exact tests were used in analyzing categorical variables. Independent sample t-test was used to analyze continuous variables. Binary logistic regression was used to perform multivariable analysis.

Results: Among the 86 patients included in this study, 55.8% were males and 44.2% were females. The average age was 54.77 ±14.5 years and average BMI was 29 ±7 kg/m². The incidence of POPC was 17.4%: respiratory failure (11.6%), respiratory deficiency and insufficiency (3.5), and pneumonia (2.3%). POPC was associated with longer surgery duration (p < 0.001), longer intubation duration (p < 0.001), postoperative intubation (p < 0.001), higher EBL (p = 0.04), high volume of irrigation (p = 0.033), postoperative CSF leak requiring surgical repair (p = 0.006), and longer length of hospital stay (p < 0.001). There was no significant association between POPC and age (p = 0.677), sex (p = 0.569), BMI (p = 0.214), gastric tube presence (p = 0.774), ETT size (p = 0.582), ratio of ETT size to patient height (p = 0.934), intraoperative CSF leak (p = 1.00), preoperative history of pulmonary disease (p = 1.00), and postsurgery cuff pressures below the recommended range of 20 to 30 cm H₂O (p = 0.639). Additionally, only 2.4% of initial ETT cuff pressures were underinflated. Regression analysis controlling for volume of irrigation, EBL, and intubation duration showed that for every additional hour a patient remained intubated, the odds of POPC was approximately 1.38 times higher (95% CI: 1.095–1.733).

Conclusion: Our study highlights the significance of POPC within the skull base patient population. Targeting perioperative risk factors including duration of surgery and intubation, postsurgical intubation status, intraoperative volume of irrigation, intraoperative blood loss, and postoperative CSF leak may decrease POPC and enhance patient outcomes.