Effects of Nondependent Lung Ventilation With Continuous Positive-Pressure Ventilation and High-Frequency Positive-Pressure Ventilation on Right-Ventricular Function During 1-Lung Ventilation

Abstract

Background. The application of volume-controlled high frequency positive pressure ventilation (HFPPV) to the nondependent lung (NL) may have comparable effects to continuous positive airway pressure (CPAP) on the right ventricular (RV) function, oxygenation, and surgical conditions during one lung ventilation (OLV) for thoracotomy. Methods. After local ethics committee approval and informed consent, 75 patients scheduled for elective thoracotomy using OLV were randomly allocated to receive nondependent lung either CPAP 2 (CPAP2; n=25) or 5 (CPAP5; n=25) cm H2O pressure setting of the device or HFPPV using VT 3 mL-1, I: E ratio <0.3 and R.R 60/min (HFPPV; n=25), followed 15 min of OLV. Intraoperative changes in RV ejection fraction (REF), end-diastolic volume (RVEDVI) and stroke work (RVSWI), stroke volume (SVI), oxygen delivery (DO2), and uptake (VO2) indices and shunt fraction (Qs: Qt) were recorded without any surgical manipulation of the lung. Results. The application of NL-HFPPV resulted in improved REF by 33%, SVI and DO2 (P < 0.01) and reduced RVEDVI, RVSWI, PVRI, oxygen uptake, and shunt fraction by 24.8% (P < 0.01) than in the NL-CPAP groups. Conclusion. We concluded that the use of NL-HFPPV is a feasible option and offers improved RV function and oxygenation during OLV for open thoracotomy.

Anesthetic Management of the Patient With Dilated Cardiomyopathy Undergoing Pulmonary Resection Surgery

“…This in turn causes an increase in RV dimensions during both systole 55 and diastole. 52,55 The former is likely a direct result of increased afterload; the latter may represent a compensatory preload reserve effect. 55 The degree to which RV afterload is increased after the onset of OLV is likely to be affected by the degree to which HPV contracts the pulmonary vascular volume of the nonventilated lung; hypercapnia 67 ; the method of oxygen delivery to the nonventilated lung 50,52 ; surgical factors, including pleural insufflation, thoracotomy, and direct lung compression; and specific anesthetics.…”

“…49,54 In a clinical study, the partial recruitment of nondependent lung tissue during OLV by the application of high-frequency PPV normalized the pulmonary vascular resistance index (PVRI) and RV end-diastolic volume index and improved RVEF by 33% compared with CPAP. 52 Though the evidence is incomplete, it appears that under normal conditions, cardiac output is not dramatically altered by the institution of OLV, though other concurrent factors such as pleural insufflation may profoundly affect hemodynamics. The primary hemodynamic effects of OLV per se are the result of effects of augmented RV afterload and decrements in RV function ( Figure 2).…”

“…Despite buffering effects, increases in PVR and PAPs can occur with the onset of OLV, 48,52 creating conditions of increased afterload for the RV. This in turn causes an increase in RV dimensions during both systole 55 and diastole.…”

“…52,55 The former is likely a direct result of increased afterload; the latter may represent a compensatory preload reserve effect. 55 The degree to which RV afterload is increased after the onset of OLV is likely to be affected by the degree to which HPV contracts the pulmonary vascular volume of the nonventilated lung; hypercapnia 67 ; the method of oxygen delivery to the nonventilated lung 50,52 ; surgical factors, including pleural insufflation, thoracotomy, and direct lung compression; and specific anesthetics. 49,54 In a clinical study, the partial recruitment of nondependent lung tissue during OLV by the application of high-frequency PPV normalized the pulmonary vascular resistance index (PVRI) and RV end-diastolic volume index and improved RVEF by 33% compared with CPAP.…”

Η Διεγχειρητική Αντιμετώπιση Της Υποξυγοναιμίας Σε Θωρακοχειρουργικές Επεμβάσεις Με Αερισμό Τους Ενός Πνεύμονα

“…Οι χωρητικότητες των πνευμόνων χρησιμεύουν για την εκτίμηση της λειτουργικής τους κατάστασης και είναι οι εξής παρακάτω. [188,189]. Η εφαρμογή τελοεκπνευστικής πίεσης φυσιολογικά αυξάνει τη CVP αυξάνοντας τη φλεβική επιστροφή στο δεξιό κόλπο της καρδιάς.…”