Effect of four different anesthetic techniques on oxygenation and intrapulmonary shunt during prolonged one-lung ventilation
- VernacularTitle:不同麻醉长时间单肺通气对肺内分流和氧合的影响
- Author:
Ying SUN
;
Yi FENG
;
Baxian YANG
- Publication Type:Journal Article
- Keywords:
Respiration, artificial;
Pulmonary circulation;
Anesthesia, epidural;
Anesthesia, inhalation
- From:
Chinese Journal of Anesthesiology
1994;0(05):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the changes in oxygenation and intrapulmonary shunt duringprolonged one-lung ventilation (OLV) and compare the effects of four different anesthetic techniques. MethodsForty ASAⅠ -Ⅱ patients (27 male, 13 female) aged 36-74 yr undergoing prolonged OLV during elective thoracicsurgery were randomly allocated to one of four groups: (1) isoflurane (GI, n = 10); (2) isoflurane + epidural(GIE, n =10); (3) propofol (GP, n = 10); (4) propofol + epidural (GPE, n = 10). Radial artery wascannulated and Swan-Ganz catheter was placed via right internal jugular vein before induction of general anesthesia.In group 2 and 4 an epidural catheter was inserted at T_(7-8) or T_(8-9) and advanced 3 .5-4.0 cm in the epidural spacecephalad. Epidural block was produced by a bolus of 0.5 % ropivacaine 7-9 ml followed by continuous infusion of0. 5 % ropivacaine at 3-5 ml?h~(-1). Anesthesia was induced with propofol 1 .0-1. 5 mg?kg~(-1), fentanyl 3?g?kg~(-1) andvecuronium 0. 1 mg?kg~(-1). A left-sided double-lumen tube was inserted and correct position was confirmed. Thepatients were mechenically ventilated. The ventilation collditions were FiO_2 = 100 %, V_T = 8-10 ml?kg~(-1), I: E =1: 5 and respiratory rate was adjusted to maintained P_(ET) CO_2 at 35-45 mm Hg during both two-lung ventilation(TLV) and OLV. Anesthesia was maintained with isoflurane inhalation in group 1 and 2 or continuous infusion ofpropofol in group 3 and 4 supplemented with intermittent i. v. boluses of fentanyl. MAP, HR, ECG, MPAP,CVP, continuous cardiac output (CCO), BIS and TOF were continuously monitored during anesthesia. BIS was maintained at 45-55. Arterial and pulmonary blood gases were analyzed before induction of anesthesia (T_1), 30min after TLV was started (T_2 ), and 5, 15, 30, 60, 120 and 180 min after OLV was started (T_(3-8)) and 30 minafter TLV was resumed (T_9 ). The Qs/Qt (shunt fraction) was calculated at T_(1-9) Results Qs/Qt was significantlyincreased after induction of general anesthesia and mechanical ventilation and increased further during OLVcompared with the baseline value (T_1) in all four groups. The calculated Qs/Qt values were highest at 15 min (T_4)or 30 min (T_5) of OLV and remained high for 30-60 min and then gradually decreasing. During OLV QS/Qt washigher in group 1 than in the other three groups (P0.05). Cardiac output was significantly higher in group 1 and 2 than thatin group 3 and 4 during OLV. Conclusion During prolonged OLV intrapulmonary shunt tends to decrease withincreasing oxygenation with time, regardless of anesthetic techniques employed. Isoflurane inhalation is associatedwith a signifficant increase in shunt fraction. Combined general and epidural anesthesia may induce greaterhemodynamic changes.
