Influence of positive end-expiratory pressure on arterial blood pressure in mechanically ventilated trauma patients in the field: a retrospective cohort study

Ventilation with positive end-expiratory pressure (PEEP) may result in decreased venous return to the heart and therefore decrease cardiac output. We evaluated the influence of PEEP ventilation on arterial blood pressure in the field in 296 posttraumatic intubated patients being treated by a helicopter emergency medical service in a retrospective cohort study. Initial systolic blood pressure on the scene, upon hospital admission and their mean difference were compared between patients being ventilated with no/low PEEP (0-0.3 kPa) and moderate PEEP (0.3-1 kPa). In a subgroup analysis of initially hemodynamic unstable patients (systolic blood pressure < 80 mmHg), systolic blood pressure was compared between patients being ventilated with no/low or moderate PEEP Further, the mean difference between initial systolic blood pressure and upon hospital admission was correlated with the chosen PEEP. Systolic arterial blood pressure of patients being ventilated with no/low PEEP improved from 105 +/- 36 mmHg to 112 +/- 38 mmHg, and that of patients being ventilated with moderate PEEP improved from 105 +/- 38 mmHg to 119 +/- 27 mmHg. In initially unstable patients being ventilated with no/low PEEP systolic blood pressure improved from initially 55 +/- 36 mmHg to 78 +/- 30 mmHg upon hospital admission, and in those being ventilated with moderate PEEP, the systolic blood pressure improved from 43 +/- 38 mmHg to 91 +/- 27 mmHg. There was no significant correlation between the chosen PEEP and the mean difference of systolic blood pressure (Pearson's correlation, r = 0.07, P = 0.17). Ventilation with moderate PEEP has no adverse effect on arterial systolic blood pressure in this cohort of trauma patients requiring mechanical ventilation. Initially unstable patients being ventilated with moderate PEEP tend to be hemodynamically more stable.