Semirecumbent position protects from pulmonary aspiration but not completely from gastroesophageal reflux in mechanically ventilated patients.

Abstract

The aim of this study was to evaluate the effect of two body positions (supine and semirecumbency) on the dynamics of gastroesophageal reflux (GER) in 15 patients requiring mechanical ventilation and having a nasogastric tube in place. Samples of gastric contents, pharyngeal and bronchial secretions, and blood were obtained at baseline and every hour during a period of 5 h after nasogastric tube isotopic instillation of 37 megabecquerels of Tc99m. Radioactivity counting (RAc) was performed using a gamma counter with correction for decay. Irrespective of the body position, all patients showed at 3, 4, and 5 h after the isotope instillation a significant increase in RAc of the oropharyngeal contents (p < 0.05, each), indicating GER. Although RAc values in the pharynx were higher in supine from 1 through 4 h (p < 0.05), at the end of the study (5 h) the values did not differ between each position. Likewise, the slopes of the regression lines of sequential oropharyngeal RAc values were not different between each position (0.39 +/- 0.09 versus 0.45 +/- 0.11, respectively). In contrast, RAc values in bronchial secretions were higher at 5 h in the supine position compared with baseline (p < 0.05) and to semirecumbency (p < 0.01). These results strongly support that GER in mechanically ventilated patients with a nasogastric tube is a feature occurring irrespective of body position. Semirecumbent position does not protect completely from GER and subsequently from oropharyngeal colonization from gastric origin.

Tracheobronchial aspiration of gastric contents in critically ill tube-fed patients: Frequency, outcomes, and risk factors

“…Among other risk factors for pneumonia identified in our study were a high sedation level, a low backrest elevation, and use of paralytics. Other investigators have reported similar findings (10,11,28). The greater incidence of pneumonia in younger patients was likely due to the relatively high proportion of young male trauma victims included in our study.…”

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

“…Radionuclide studies reveal increased tracheal penetration of gastric contents when intubated patients are supine (85,159,201). Drakulovic et al found that the simple elevation of the head of bed to 45°results in dramatic reductions in VAP incidence and a trend toward reduced mortality (54).…”

A Nursing Clinical Decision Support System and Potential Predictors of Head-of-Bed Position for Patients Receiving Mechanical Ventilation

“…4,5 Additionally, lower head-of-bed (HOB) elevations have been associated with higher rates of aspiration. [6][7][8][9][10][11] Despite the evidence that HOB elevation (30º-45º) helps prevent aspiration in patients receiving mechanical ventilation, the intervention is underused. [11][12][13] tion due to interpretation error by a nurse.…”