病患自控式止痛嗎啡對於子宮切除後腸蠕動的影響

The Effect of IVPCA Morphine on Post-hysterectomy Bowel Function

背景：嗎啡會引起腸蠕動失調，而且是以劑量效應的方式來表現，只是之前這類的研究是以單次劑量的給予來探討。近年來，經靜脈病患自控式止痛提供了一個非常滿意的止痛效果。這樣的給藥方式減少了巔峰的血中藥物濃度，在藥物動力學方面的作用類似持續靜脈給藥的方式。目前還沒有報告研究經靜脈病患自控式止痛對腸蠕動的影響。方法：我們收集了五十一位接受子宮切除手術的病人來研究經由病患自控式止痛所使用的嗎啡量和排氣時間的關係，而嗎啡是在手術後立即利用經靜脈病患自控式止痛幫浦來給予。結果：我們發現其中四十九個病人可以有效的解除疼痛或只表現輕微的疼痛，嗎啡平均使用量為16.9 mg，而平均排氣時間為2036.4分鐘，結果顯示此類手術病患使用自控式止痛裝置時，嗎啡的使用量和排氣時間之間並無關聯性。結論：在有效治療劑量下使用經靜脈病患自控式止痛的嗎啡給予方式可以減少嗎啡所引起的腸蠕動失調。

Background: Although morphine has been shown to induce bowel dysfunction in a dose-dependent fashion, in most relevant studies it was investigated in single bolus injection. Recently, intravenous morphine via patient-controlled analgesia (IVPCA) has been widely used to provide analgesia by divided bolus doses on patients' demand with satisfactory effects. This approach, by reducing the peak serum surge, largely resembles the pharmacokinetic and pharmacodynamic advantage of continuous infusion. There is yet no report on the investigation of its effect on post-operative bowel dysfunction. Methods: Fifty-one women who underwent abdominal total hysterectomy (ATH) due to uterine myoma were enrolled to investigate the association between the doses of morphine consumption by PCA and the time of first passage of flatus. In all patients morphine was administered intravenously via a PCA pump immediately after recovery from general anesthesia. Results: We found that 49 out of 51 patients (96%) exhibited mild pain with IVPCA morphine. They had consumed an average dose of 16.9 mg morphine (range, 0-46 mg) upon the first passage of flatus which occurred 2036.4 min (average) post-operatively. There was no correlation between the dose of morphine and the time of first passage of flatus (r = 0.053, P >0.05). Conclusions: The absence of suppression of bowel movement by IVPCA morphine for post-operative pain control suggests that favorable pharmacokinetic profile of IVPCA can help reduce the morphine-induced bowel dysfunction at its therapeutic level.