Accurate Tidal Volume for Patients under Mechanical Ventilation: A Cross-sectional Descriptive Study

Abstract

Background: In order to prevent lung injury among patients under mechanical ventilation, tidal volume should be determined based on predicted body weight. The aim of the study was to determine the accuracy of tidal volume determination for patients under mechanical ventilation and to assess nurses’ knowledge about accurate tidal volume determination.

Methods: This was a cross-sectional descriptive study. This study was conducted on 250 patients under mechanical ventilation and 75 nurses who provided care to the patients. Patients’ height was estimated based on their ulna length and then, their predicted body weight and tidal volume were estimated. Nurses’ knowledge about tidal volume determination was also assessed.

Results: The mean of delivered tidal volume was 9.1±1.73 mL/kg of predicted body weight. Tidal volume for 172 patients (68.8%) had been set at more than 8 mL/kg of predicted body weight. Forty nine nurses (65.3%) noted that there was no guideline in their wards for height and weight measurement. They determined patients’ weight and height through either visual estimation (21 nurses; 28.0%) or asking from their colleagues, patients, or patients’ family members (48 nurses; 64.0%).

Conclusion: Nurses have limited knowledge about accurate tidal volume determination and hence, deliver high tidal volume to patients under mechanical ventilation which puts them at risk for ventilator-associated lung injury. Urgent interventions such as lung-protective strategies, staff training, and careful managerial supervision are needed to prevent ventilator-associated lung injury and improve patient safety.