Pulmonary effects of thoracic epidural analgesia for cardiac valve replacement surgery

الملخص EN

The study was performed on forty patients (ASA physical status II: HI) with symptomatic mitral valve disease underwent mitral valve replacement surgery.The patients where criteria were randomly allocated into two equal groupsQO patients each) : 1- General anesthesia group [GA] (control group) .

2- General anesthesia with thoracic epidural analgesia group (TEA group).

Anesthetic technique and management of cardiopulmonary bypass were standardized for all patients.

Parameters assessed: Spirometric data: (FVC, FEV1, FEVU FVC % and PEFR), and respiratory rate were measured at the night before surgery, after extubation by lh, 12h, 24h, 48h, 72h & 6th postoperative day.

Arterial Blood Gases: Pa02 ,PaC02 and pH were measured after induction of GA by 15 min., after extubation by 48h, 72h & 6th postoperative day.

Visual analogue scale (VAS) score for assessement of pain was measured after extubation by lh, 6h, 12h, 18h, 24h, 48h, 72h & 6th postoperative day..Total dose of fentanyl analgesia was calculated in each group.

Results:.

There were some improvement in respiratory function (FVC, FEV] and PEFR) started at the 3rd to the 6'h postoperative days .There were insignificant changes in FEVU FVC all over the study period.

RR decreased significantly in the epidural group than control group in all readings.

There was a significant decrease in VAS in TEA group than the control group throughout the study period.

Pa02 was significantly decreased in both groups at all readings.

* Postoperative data: 1.Intensive Care Unit (1CU) stay: There was insignificant difference between the two groups.

l.Time to first awake /hour was significantly decreased in thoracic epidural group than general anesthesia group (1.3 ± 0.3 versus 2.5 ± 0.6).

3.

Time to extubation /hour was significantly decreased in thoracic epidural group than general anesthesia group (3.5 ± 0.2 versus 7.3± 0.3).

4.

Total postoperative fentanyl consuption in 1st 24h was a significant decrease in TEA than GA group (p<0.001) [677.9± 26 in TEA group versus 1203.4 ± 44 in general anesthesia group] In conclusion, perioperative epidural infusion of 0.125% bupivacaine and fentanyl, started before induction of anesthesia in valve replacement surgery reduces the total requirements of intraoperative narcotics, without an appreciable delay in extubation.

There was slight improvement in pulmonary function, but not to expected values andfar less than control reading indicating multifactorial bases of pulmonary dysfunction in cardiac surgery using CBP.