The Hemodynamic and Respiratory Effects of Continuous Negative and Control-Mode Cuirass Ventilation in Recently Extubated Cardiac Surgery Patients: Part 2

ObjectiveNegative-pressure ventilation (NPV) by external cuirass (RTX; Deminax Medical Instruments Limited, London, UK) in intubated patients after cardiac surgery improves hemodynamics measured by pulmonary artery catheter (PAC)-based methods with increased cardiac output (CO) and stroke volume (SV) without changing the heart rate (HR). The less-invasive pressure recording analytical method (PRAM) (MostCare; Vytech Health srl, Padova, Italy) allows radial artery monitoring of CO, SV, SV variation, and cardiac cycle efficiency (CCE). The authors investigated the hypothesis that NPV improves PRAM-based hemodynamics and arterial blood gas analysis in extubated cardiac surgery patients.DesignA clinical investigation.SettingA teaching hospital.ParticipantsTwenty recently extubated cardiac surgery patients.InterventionsFive consecutive experimental ventilation modalities lasted 5 minutes: (1) baseline (no cuirass ventilation), (2) mode 1 (cuirass ventilation with a continuous negative pressure of −20 cmH2O), (3) rest 1 (no cuirass ventilation), (4) mode 2 (cuirass ventilation in the control mode of 12 breaths/min at −20 cmH2O, and (5) rest 2.Measurements and Main ResultsPRAM parameters were analyzed throughout the final minute of each experimental modality, concluding with arterial blood gas sampling. NPV was well tolerated. HR was unchanged. Mode 2 SV was higher than baseline and rest 2. Mode 2 CO was higher than rest 2. Rest 2 systolic blood pressure was lower than rest 1 and mode 2. Increased CCE with NPV was not significant (p = 0.0696). Oxygenation and PCO2 were unchanged although mode 2 pH increased.ConclusionsExtubated sedated cardiac surgery patients comfortably tolerated NPV with unchanged HR. SV and pH increased.