One-lung ventilation under general anesthesia: is it appropriate for thoracic surgery?

ABSTRACT

The study comprised 30 [ASA grades II and III] patients aged 47-72 years, randomly allocated into three equal groups [n=10] according to type of anesthesia administered and number of lungs ventilated Group I anesthetized using continuous intravenous general anesthesia [GA] with two-lung ventilation [TLV], group II received GA with one-lung ventilation [OLV] and group III received thoracic epidural anesthesia [TEA] combined with GA with OLV. Arterial and venous blood gases, heart rate HR], and mean arterial pressure [MAP] were measured during TLV, 15 [OLV+15] and 30 min after beginning OLV [OLV+30]. Duration of surgery, the number of blood bags used for transfusion, and postoperative analgesia requirements were recorded. Hemodynamic parameters showed nonsignificant changes between patients administered GA, whereas there was significant [P<0.05] decrease in MAP and HR in TEA group and 7 patients required administration of 10 mg of IV ephedrine in group III. OLV resulted in significant [P<0.05] reduction of PaO2, SaO2, CaO2 and Cc02 in groups II and III at OLV+15 compared to group I, and in group III compared to group II. At OLV+30, there was significant [P<0.05] reduction of all measured pamameters in groups II and III compared to group I. and in group III compared versus group II. All patients showed an increased Qs/ Qt% 15 and 30 min after OLV, however, the increase was significant [P<0.05] in groups II and III compared both to group I and to their percentages measured during TLV. Despite the non-significant difference between groups II and III, at OLV+15, there was a significant [P<0.05] increase of Qs/Qt% in group III, at OLV+30 compared to group II. Hemoglobin [Hb] concentrations showed a significant [P<0.05] decrease at OLV+30 in all patients compared to their starting levels. Group II showed the least decrease of Hb concentration. OLV had significantly [P<0.05] reduced the duration of surgery in group II compared to group I and non-significantly compared to group III. Furthermore, OLV had significantly [P<0.05] reduced the need of blood transfusion in both group II and III compared to group I. All patients included in groups I and II required postoperative analgesia, while only 4 patients in group III required additional analgesia. There were no complications encountered with TEA technique. We can conclude that OLV under TEA combined with general anesthesia is not appropriate for thoracic surgical procedures while OLV under continuous general intravenous anesthesia is appropriate for safe thoracic surgical procedures