The effect of epidural dexmedetomidine on oxygenation and shunt fraction in patients undergoing thoracotomy and one lung ventilation: A randomized controlled study

Abstract

Background and Aims:Role of epidural dexmedetomidine in providing analgesia is well documented, but its effect on oxygenation and shunt fraction is not well established. We studied the hypothesis that epidural dexmedetomidine may improve oxygenation and shunt fraction during one-lung ventilation (OLV).Material and Methods:After taking Institutional Ethics Committee approval, sixty patients undergoing thoracotomy and OLV were randomized to receive epidural ropivacaine with saline (RS group) or epidural ropivacaine with dexmedetomidine (RD group). Group RS received 7 ml of ropivacaine 0.5% with 1.5 ml normal saline (NS) bolus while RD group received 7 ml of 0.5% ropivacaine with 1 mcg/kg dexmedetomidine reconstituted in 1.5 ml NS. This was followed by infusion of 5 ml/h of 0.5% ropivacaine in RS group and 5 ml/h of 0.5% ropivacaine containing 0.2 mcg/kg of dexmedetomidine in RD group. Arterial and central venous blood gas parameters were obtained 15 minutes after intubation during two lung ventilation (TLV15), 15 and 45 min after OLV (OLV15, OLV45) and 15 minutes after reinstitution of two lung ventilation (ReTLV).Results:RD group had better oxygenation (254.2 ± 72.3 mmHg, 240.60 ± 59.26 mmHg) as compared to RS group (215.2 ± 64.3 mmHg, 190.7 ± 61.48 mmHg) at OLV15 (P – 0.04) and OLV45 (P – 0.004) respectively. Shunt fraction in RD group was (30.31 ± 7.89%, 33.76 ± 8.89%) and (35.14 ± 7.58%, 39.57 ± 13.03%) in RS group at OLV15 and OLV45, respectively. The increase in the shunt fraction from TLV15 was significantly greater in RS group than RD group both at OLV15 (P – 0.03) and OLV45 (P – 0.03). The sevoflurane and fentanyl requirement was lower in RD group.Conclusion:Epidural dexmedetomidine improves oxygenation and reduces shunt fraction during OLV, in patients undergoing thoracotomy. It also reduces intraoperative anesthetic and analgesic requirement.

Effect of dexmedetomidine on lung function and prognosis a systematic review and meta-analysis

“…Meta-analysis of pH Seven trials including 345 patients reported pH (20,23,24,(26)(27)(28)(29). The pooled data showed no signi cant difference between the dexmedetomidine group and the placebo group (MD: 0.03; 95% CI: from 0.00 to 0.07, p=0.04).…”

“…After searching the database and comparing the present criteria, a total of 17 trials were included in the meta-analysis (16,19,20,(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). These trials are all randomized control trials.…”

“…Two trials didn't give enough information about their randomization (19,20). Six trials had the right method of their allocation concealment (16,20,27,29,31,33). Blinding was used in thirteen trials (16, 19, 20, 22, 24-27, 29-31, 33, 34).…”

“…Eight trials including 536 patients reported PaO 2(19,20,(26)(27)(28)(33)(34)(35). The pooled data showed signi cant higher PaO 2 in the dexmedetomidine group than the placebo group (MD: 10.96; 95% CI: from 0.77 to 21.15; p=0.04).…”

Epidural dexmedetomidine infusion for perioperative analgesia in patients undergoing abdominal cancer surgery: randomized trial

“…It deserves mentioning that dexmedetomidine had been administered through epidural infusion in a dose of 0.2 µg/kg/h during the intraoperative period only, and they claimed that it improves oxygenation and reduces the shunt fraction during one lung ventilation. 28 …”