Objective  To evaluate the hemodynamic status by transesophageal echocardiography (TEE) during one-lung ventilation with low tidal volume and positive end-expiratory pressure (PEEP) in left lateral position.

  Methods  Ten American Society of Anesthesiologists (ASA) class Ⅰ or Ⅱ patients undergoing elective right lung lobectomy in left lateral position were included in the study. After induction of anesthesia, ventilation parameters were set at TV 4-6 ml/kg, PEEP 4-6 cm H₂O, and RR 12-16/min, maintaining (end-tidal carbon dioxide, EtCO₂) at 35-40 mmHg and SpO₂ > 96%. Thirty min later (about 15 min after central venous line insertion), heart rate (HR), blood pressure (BP), and central venous pressure (CVP) were recorded. Left ventricular ejection fraction (EF), stroke volume (SV), cardiac output (CO), cardiac index (CI), stroke index (SI), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular dimension fractional shortening (LVDFS), and systemic vascular resistance (SVR) were measured by TEE through transgastric left ventricle short axis view during two-lung ventilation in supine position. Then, the patient was turned to left lateral position. One-lung ventilation was set just before thoracic cavity was opened and all the same hemodynamic data were repeatedly measured 15 min later.

  Results  There were no significant difference in HR, SBP, DBP, CVP, EF, CO, CI, LVESV, LVEDV, LVDFS, and SVR between left lateral one-lung ventilation and supine two-lung ventilation with low tidal volume and PEEP. However, the SV and SI significantly increased in left lateral one-lung ventilation, (69.23±20.01) ml vs. (56.97±22.02) ml and (40.67±8.35) ml/m² vs. (32.45±8.78) ml/m² (P < 0.05).

  Conclusion  When ventilated with low tidal volume and PEEP, one-way ventilation in left lateral position will not remarkably influence the hemodynamic status and cardiac function.