Efficacy of Programmed Intermittent Bolus Epidural Analgesia in Thoracic Surgery

A Randomized Controlled Trial

M. Higashi; K. Shigematsu; E. Nakamori; S. Sakurai; K. Yamaura

Disclosures

BMC Anesthesiol. 2019;19(107) 

In This Article

Discussion

Our results showed that PIB has an analgesic effect comparable with that of CEI and reduces the required amount of local anesthetic on the first day after thoracotomy. However, adverse events, such as hypotension, need attention.

To compensate for the limitations of CEI, such as a restricted area of analgesic effect, the technique of intermittent bolus infusion of epidural analgesics has been developed. The advantage of PIB is mainly in the maintenance of labor analgesia.[5,7] Its use has been recently demonstrated in total knee arthroplasty and major abdominal and gynecological surgery, and its utility has been shown.[8–10] However, to our knowledge, this is the first randomized study to show the advantage of PIB in thoracotomy.

The reduction in the total amount of local anesthetic with intermittent bolus infusion compared with continuous infusion is consistent with the findings in labor analgesia reports and postoperative reports. In major abdominal and gynecological surgery, the beneficial effect of PIB is noted on the first postoperative day and not on the day of the operation.[9] Sequential epidural bolus infusion provides superior epidural block compared with CEI.[2]

Compared with bolus infusion, hemodynamic stability with CEI without bolus administration is superior; the incidence of hypotension reduced by 67% without using bolus infusion compared with that using bolus infusion.[11] However, PIB studies for postsurgical analgesia indicated no adverse effects.[8–10] With regard to the incidence of hypotension, the difference between our results and those of previous reports might be associated with differences in the site of epidural anesthesia and dose of local anesthetic. Hypotension occurred but was not significant in both groups, and there was a need for noradrenalin when epidural anesthesia involved puncture at Th8–10.[9] On the other hand, when epidural anesthesia involved puncture at Th10–12 in open gynecological surgery[8] or L3–5 in total knee arthroplasty,[8] there was no hypotension requiring intervention. The bolus dose was 6 mL every hour in the major surgical study that reported hypotension,[9] and among studies that did not report hypotension, the doses were 4 mL every hour for open gynecological surgery[10] and 3 mL every hour for total knee arthroplasty.[8] We used a bolus of 5.1 mL every 90 min (3.4 mL every hour). Therefore, when PIB and CEI are used for a higher level of thoracic epidural anesthesia, attention should be paid to the bolus dose to avoid hypotension.

The present study has limitations. First, this is not double blinded study. Second, in this study, the dose and concentration of local anesthetic was single, and the total dose of local anesthetic and counts of PCA were less than that of preliminary studies. We need to re-examine the small dose and concentration of local anesthetics in future studies.

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