[Impact of adaptive positive end expiratory pressure and mechanical ventilation on hemodynamics and oxygen kinetics in post-liver transplantation patients].

OBJECTIVE: To determine the impact of adaptive positive end expiratory pressure (PEEP) and mechanical ventilation on hemodynamics and oxygen kinetics in post-liver transplantation patients.

METHODS: The study included 11 patients who accepted mechanical ventilation after piggyback liver transplantation. Swan-Ganz catheter and radial artery catheter were used to monitor the cardiac output (CO), mean pulmonary arterial pressure (MPAP), mean arterial blood pressure (MABP) and central venous pressure (CVP) and airway pressure. After transplantation, PEEP of 0, 5, 10 and 15 cm H(2)O (1 cm H(2)O=0.098 kPa) was instituted to support the ventilation alternately. After 30 minutes, pressure regulated volume controlled ventilation (PRVCV) and pressure controlled synchronized intermittent mandatory ventilation+pressure support ventilation (PC-SIMV+PSV) were used to support the ventilation alternately and the indexes of hemodynamics and oxygen kinetics were analyzed.

RESULTS: The data showed that differences existed in peak airway pressure, mean airway pressure, CVP and MPAP when different levels of PEEP were used. These indexes were significantly higher in PEEP of 15 and 10 cm H(2)O than those in PEEP of 0 and 5 cm H(2)O.There were no differences in pH, partial pressure of carbon dioxide in arterial blood (PaCO(2)), pressure of oxygen in arterial blood (PaO(2)), arterial oxygen saturation (SaO(2)), oxygen delivery (DO(2)), oxygen consumption (VO(2)) and oxygen extraction rate (O(2)ER) at different levels of PEEP. The airway pressure was significantly lower under PRVCV pattern than those under PC-SIMV+PSV pattern [(8.78+/-1.53) cm H(2)O vs. (11.64+/-3.30) cm H(2)O, P<0.05]. There were no differences in other indexes between these two mechanical ventilation patterns.

CONCLUSION: These date suggested that a low level of PEEP (5 cm H(2)O) during mechanical ventilation should be used in post-liver transplantation patients in order to decrease the influence of PEEP on systemic circulation and hepatic regurgitation. PRVCV could be a more suitable mechanical ventilation pattern for patient after liver transplantation.