Errors regarding specific preventive measures of ventilator-associated pneumonia in the ICU

Introduction

Prevention of aspiration-induced ventilator-associated pneumonia (VAP) includes, among other factors, head elevation, appropriate cuff pressure and correct positioning of nasogastric tubes. The purpose of the study was to identify errors regarding these prevention measures in critically ill ICU patients.

Methods

We included all mechanically ventilated patients hospitalized in our seven-bed ICU. We prospectively collected the demographics and positioning of the patients (degrees), cuff pressures (mmHg) and correct position of the nasogastric tubes in the stomach at 08:00 every day for six consecutive months.

Results

We included 37 patients (25 males) of mean age 66.9 ± 3.3 years and illness severity scores of SAPS II 53.05 ± 1.5 and SOFA 7.2 ± 0.3. In total we had 267 observations. The mean cuff pressure was 26.8 ± 0.9 mmHg. The mean slope of the patients' bed was 29.5 ± 0.4°. The mean volume of the oropharyngeal aspirates was 9.9 ± 0.4 ml and of tracheal aspirates was 7.1 ± 0.2 ml. In 24 and 69 observations, tracheal and oropharyngeal aspirates, respectively, were >10 ml. In 109/267 (40.1%) observations. the slope of the patients was <30°. All patients had at least one positioning with a slope <30°. In 64/267 (23.9%) observations, the cuff pressures were <20.0 mmHg. One-half of the patients had at least one measurement <20.0 mmHg. In 10 cases, the end of the nasogastric tube was in the esophagus and in five cases it was obstructed. Twenty patients developed VAP (20/37, 54.1%). Patients with a large amount of oropharyngeal aspirates (>10 ml) and low cuff pressures (<20 mmHg) had a significantly higher incidence of subsequent VAP (72.2% vs 36.8%) compared with those with a low amount of oropharyngeal aspirates (<5 ml) and normal cuff pressures (chi-square test, P = 0.049; RR = 1.960, CI = 1.018–3.774; OD = 4.457, CI = 1.110–17.90).

Conclusion

Errors regarding specific prevention measures of VAP are frequently observed. Our data also show the significance of the amount of oropharyngeal aspirates and cuff pressures for the subsequent development of VAP. The tightness of the stomach–oropharyngeal–tracheal axis seems to be a significant factor influencing the subsequent development of VAP.