Effect of different modes of one-lung ventilation on mechanics of respiratory mechanics, hemodynamics and arterial oxygen tension in pediatric patients / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of different modes of one-lung ventilation ( OLV) on respiratory mechanics, hemodynamics and arterial oxygen tension ( PaO2) in pediatric patients. Methods Thirty-four ASA Ⅰ - Ⅱ patients (14 male, 20 female) aged 2-10 yr, weighing 8-26 kg undergoing abdominal surgery or operations on extremities were enrolled in this study. The patients were premedicated with intramuscular phenobarbital 2-3 mg ? kg-1 and atropine 0.015 mg ? kg-1 . In the operating room the patients were given intramuscular midazolam 0.25 mg? kg-1 and ketamine 2.5 mg ? kg-1 before intravenous line and EGG, NIBP and SpO2 monitoring were established. Anesthesia was induced with intravenous fentanyl 3-5 ?g kg-1 and vecuronium 0.1 mg? kg-1 and maintained with isoflurane inhalation supplemented with intermittent iv boluses of fentanyl and vecuronium. In patients aged over 5 yr Univent (Fuji Corpi) was inserted and left main bronchus was blocked during OLV. In patients less than 5 yr ordinary tracheal tube was inserted and was advanced into right main bronchus during OLV. Correct positioning of the tube was checked by fiberoptic bronchoscopy or auscultation. The test consisted of three steps: firstly two-lung ventilation (TLV) with volume-control mode; secondly OLV with volume-control mode;lastly OLV with pressure-control mode. During first and second step VT was set at 8-10 ml kg-1 and respiratory rate was adjusted to maintain PETCO2 between 4.5-6.0 kPa. During the third step (OLV with pressure-control mode) the inspiratory pressure was set according to the plateau pressure during step 1 and 2 (volume-control mode). Each step was maintained for 25 min before respiratory mechanics , hemodynamics and PaO2 were measured and recorded.Results During OLV with volume-control mode (second step) , peak pressure (Ppeak), plateau pressure (Pplat) and airway resistance (Raw) were significantly higher but dynamic compliance was significantly lower, cardiac output (CO) and stroke volume (SV) were significant lower but systemic vascular resistance (SVR) was significantly higher and PaO2 was significantly lower than those during first step (two lung ventilation with volume-control mode) (P