Reverse Trendelenburg Positioning and Its Effect on Outcomes: a Retrospective Study of Consecutive Patients

Intraoperative pulmonary aspiration can cause death and lead to morbidity. In addition, reliable estimates of aspiration rates are uncertain. In part, this ambiguity relates to the lack of prospective data. Relevant studies are retrospective chart reviews or results from voluntary reporting databases. Furthermore, aspiration diagnosis can be imprecise. The finding is certain when there is aspiration of bile or particulate matter from the tracheobronchial tree or there is endoscopic visualization. However, the diagnosis is presumptive when there is intraoperative or postoperative development of a new chest x-ray infiltrate and attendant tachypnea, hypoxia, wheezing, or changes in ventilator airway pressures.

Most patients undergoing general endotracheal anesthesia are in the supine or horizontal position. However, evidence from the literature demonstrates that the supine position in mechanically ventilated patients is a risk for aspiration and ventilator associated pneumonia (VAP). During intensive care unit (ICU) mechanical ventilation, the Institute for Healthcare Improvement recommends elevating the head of the bed to prevent pulmonary aspiration and VAP. Other investigations have shown a profound relationship between horizontal positioning and intra-operative aspiration. There is substantial operating room, ICU, and animal investigative evidence that aspiration occurs despite the presence of a cuffed endotracheal tube. Likewise, previous work by this group showed a 30% perioperative hypoxemia rate, which was significantly associated with horizontal positioning. The post-operative length of hospital stay was 2 days longer with hypoxemia, compared to no hypoxemia (p <0.0001) and this represented a total of 300 additional days for the 2 months of the study.

The purpose of this retrospective study is to repeat the investigation after adopting a recent policy change of 10-degree Reverse Trendelenburg position as the routine for surgical patients, unless deemed inappropriate by either the anesthesiology or operating room nursing staff.

Inclusion criteria

• Patients undergoing endotracheal intubation and general anesthesia
• Age ≥18 years
• Glasgow Coma Scale score ≥13 (prior to tracheal intubation)
• American Society of Anesthesiologists classification I-IV
• Pre-operative pulmonary stability

Exclusion criteria

• Tracheal intubation prior to emergency department arrival
• Cardiac and thoracic surgical patients