Changes Of Haemodynamics,pulmonary Mechanics And Blood Gas Of Different Ventilatory Pattern During One-lung Ventilation

During one-lung Vedilation (OLV), there are many changes in pulmonarymechani c s,haemo dynaxni c s and arteri al oxy gen te nsion. Hypoxemia is a c onuno nProblem of OLV "'To investigate these changes in pediatric patienis, we studied 20 patentductus arteriosus (PDA) children, 5.29 f 3.62 years old, 18.33 tkg weigh, Whowere undergoing left thoracotomy PDA ligation with right OLV The patientswere divided into three grouPs according to the mechanical vefitilation modesduring surgery as fOllows: First grouP (n=20), two-lung venilation wth volumecontrolled (TLV-VCV); second grouP (n=20), one-lung velltlation with volumecontrolled (OLV- VCV); third grouP (n=20), one-lung ventilation with pressurecontro1led (OLV-PCV).After two-lung venti1ation with VCV one-lung venii1ation was started byVCV and the ventilation mode was then switched to PCV A1l measurementwere made 25 min after initiation of eath ventilation mode. We observed therespiratory mechanics index by side stream spiromeny (SSS), including peakairway pressure (Ppeak),plateau pressure (Pplat),airway resistance (Raw),lungcompliance (Cdyn) and inspiratory and expiratory minute ventilation (Mvi.Mve). In patients over 5 years old (n=15), we measured cardiac outPut(CO),stroke volume (SV),systemic vascular resistance (SVR),left ventricularejection time (LVETi) and aortic blood flow acceleration (ACC),by using thetransesophageal Doppler (TED)monitor. Arterial blood gases was determined inevery ventilation mode.Result: comparing OLV-VCV with TLV-VCV Ppeak,Pplat and Raw weresignificanly higher durng OLV-VCV (P<0.0l), Whereas Cdyn was significantlylower (P<0.01). CO and SV decreased as SVR incr6ased during OLV-VCV(P<0.05) and arterial oxygen pressure (PaO2) significatly decreased (P<0.0l).ComParing OLV-PCV with OLV-VCV Ppeak,and RaW decreased a bit, butthere were no significamly difference (P>0.05)during OLV-PCV PaO2significantly increased (P<0.05).We conclude that respiratory mechanics, haemodynamics and arterialoxygen tension deteriorated, which result in hypoxemia during one-lungventilation. Pressure condolled ventilation aPpeared tO be an altemative tovolume controlled ventilation in pediatric Paienis requiring one-lunganaesthesia.