A Comparison between High Frequency Positive Pressure Ventilation and Intermittent Positive Pressure Ventilation during Closed Mitral Valvotomy

Background: Patients with tight mitral stenosis usually suffer low cardiac output symptoms and elevated pulmonary vascular resistance. They may be candidates for the use of high frequency positive pressure ventilation (HFPPV). We aimed to compare HFPPV with intermittent positive pressure ventilation (IPPV) in patients subjected to closed mitral valvotomy (CMV). Methods: Twenty-four patients subjected to closed mitral valvotomy were randomly allocated to ventilation with IPPV or HFPPV. The minute volume in the IPPV group was given as a tidal volume of 10 ml/kg and a respiratory rate of 14 breaths/min, while in the HFPPV it was given as a tidal volume of 3 ml/kg and a respiratory rate of 60 breaths/min. Heart rate, arterial blood pressure, right atrial pressure (RAP), O2 saturation (SpO2), end-tidal CO2 (PeCO2), arterial CO2 tension (PaCO2) and arterial O2 tension (PaO2) were recorded during the procedure. In addition, interferences to correct hypoxaemia were recorded. Dead space fraction was calculated. Results: RAP decreased significantly during surgery in HFPPV group when compared to IPPV group. Interferences with manual ventilation to correct hypoxaemia were less frequent in HFPPV group compared to IPPV group. In each group dead space fraction increased significantly during surgery when compared to the baseline values. Surgeon's complaint was more frequent in IPPV group. Conclusion: The use of HFPPV during closed mitral valvotomy provides a safe alternative to the conventional IPPV with possible better right side unloading, less hypoxic episodes and better surgical conditions.