Changes of haemodynamics, pulmonary mechanics and blood gas in different ventilatory modes during one-lung ventilation

Objective To investigate the changes of haemodynamics, pulmonary mechanics and blood gas in volume controlled and pressure controlled ventilatory patterns during one-lung ventilation (OLV). Methods 20 patients with patent ductus arteriosus ( PDA) underwent left thoracotomy PDA ligation with right OLV. The patients were divided into three groups: two-lung ventilation with volume controlled ( TLV-VCV), one-lung ventilation with volume controlled ( OLV-VCV), and one-lung ventilation with pressure controlled (OLV-PCV). After two-lung ventilation with VCV .one-lung ventilation was started by VCV and the ventilation mode was then switched to PCV. All measurements were made 25 min after initiation of the ventilation mode. The respiratory mechanics index was measured by side stream spirometry ( SSS), including peak airway pressure (Ppeak), plateau pressure (Pplat), airway resistance ( Raw), lung compliance ( Cdyn) and inspiratory and expiratory minute ventilation (Mvi, Mve). Cardiac output (CO),stroke volume (S