Hemodynamic Consequence of Hand Ventilation Versus Machine Ventilation During Transport After Cardiac Surgery

Abstract

Manual hand ventilation and portable machine ventilation are both widely used during in-hospital transport of intubated patients following surgery, but the comparative safety and reliability of each mode of ventilation are still unclear. This prospective randomized study aimed at examining the hemodynamic consequences of manual and portable ventilation during transport from the operating room (OR) to the intensive care unit (ICU) in intubated patients following cardiac surgery. The study also hypothesized that manual ventilation after cardiac surgery would result in greater changes in measured end-tidal carbon dioxide (ETCO2) and pulmonary artery (PA) pressure when compared to machine ventilation. The study data were composed of 36 cardiac surgery patients with planned intubation during transport to the ICU. Following surgery, the patients were randomized into 2 cohorts to receive either manual ventilation (with a self-inflating bag-valve resuscitator) or machine ventilation (attached to a portable transport ventilator) during in-hospital transport. Hand ventilation was done by the anesthesiologist who provided care during surgery, and machine ventilation was set by a respiratory therapist to match parameters in the OR at the end of the case. Hemodynamic variables, ETCO2, and PA pressures before and during transport and upon arrival in the ICU were recorded. A 2-sided, unpaired t test was used to determine differences between values, and a threshold P < 0.05 was considered statistically significant. The 3 study outcomes measured were the difference from baseline ETCO2, hemodynamic changes from baseline, and changes in PA pressure before and after transport. There was no difference in transport time between hand-ventilated (mean, 5 ± 1.41 minutes) and machine-ventilated (mean, 5.47 ± 1.74 minutes) patients (P = 0.369). The transport ETCO2 excursion was significantly different between hand-ventilated (5.44) and machineventilated patients (2.32, P = 0.0126), but the total ETCO2 excursion was not significant (P = 0.066). These differences were not associated with a difference inmean PA pressure. No differences were found in mean arterial pressure, heart rate, or SpO2 (ICU vs OR). In conclusion, manual ventilation was associated with greater changes from baseline ETCO2 than machine ventilation during transport after cardiac surgery, but these differences were not associated with changes in mean PA pressure, vital signs, oxygen saturation, or heart rhythm upon arrival at ICU. The results do not support routine use of a transport ventilator in patients transported after cardiac surgery.