Mathews Timothy J, Churchhouse Antonia M D, Housden Tessa, Dunning Joel
Department of Thoracic Surgery, Royal Infirmary of Edinburgh, Edinburgh, UK.
Interact Cardiovasc Thorac Surg. 2012 Feb;14(2):194-9. doi: 10.1093/icvts/ivr081. Epub 2011 Nov 28.
A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'is the addition of ketamine to morphine patient-controlled analgesia (PCA) following thoracic surgery superior to morphine alone'. Altogether 201 papers were found using the reported search, of which nine represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This consisted of one systematic review of PCA morphine with ketamine (PCA-MK) trials, one meta-analysis of PCA-MK trials, four randomized controlled trials of PCA-MK, one meta-analysis of trials using a variety of peri-operative ketamine regimes and two cohort studies of PCA-MK. Main outcomes measured included pain score rated on visual analogue scale, morphine consumption and incidence of psychotomimetic side effects/hallucination. Two papers reported the measurements of respiratory function. This evidence shows that adding ketamine to morphine PCA is safe, with a reported incidence of hallucination requiring intervention of 2.9%, and a meta-analysis finding an incidence of all central nervous system side effects of 18% compared with 15% with morphine alone, P = 0.31, RR 1.27 with 95% CI (0.8-2.01). All randomized controlled trials of its use following thoracic surgery found no hallucination or psychological side effect. All five studies in thoracic surgery (n = 243) found reduced morphine requirements with PCA-MK. Pain scores were significantly lower in PCA-MK patients in thoracic surgery papers, with one paper additionally reporting increased patient satisfaction. However, no significant improvement was found in a meta-analysis of five papers studying PCA-MK in a variety of surgical settings. Both papers reporting respiratory outcomes found improved oxygen saturations and PaCO(2) levels in PCA-MK patients following thoracic surgery. We conclude that adding low-dose ketamine to morphine PCA is safe and post-thoracotomy may provide better pain control than PCA with morphine alone (PCA-MO), with reduced morphine consumption and possible improvement in respiratory function. These studies thus support the routine use of PCA-MK instead of PCA-MO to improve post-thoracotomy pain control.
一篇胸外科最佳证据主题文章是按照结构化方案撰写的。所探讨的问题是“胸外科手术后在吗啡患者自控镇痛（PCA）中添加氯胺酮是否优于单纯使用吗啡”。通过报告的检索共找到201篇论文，其中9篇代表了回答该临床问题的最佳证据。这些论文的作者、期刊、发表日期和国家、所研究的患者群体、研究类型、相关结局及结果均列于表格中。这包括一篇关于氯胺酮与吗啡PCA（PCA-MK）试验的系统评价、一篇PCA-MK试验的荟萃分析、四项PCA-MK的随机对照试验、一篇关于使用各种围手术期氯胺酮方案的试验的荟萃分析以及两项PCA-MK的队列研究。所测量的主要结局包括视觉模拟量表评分的疼痛评分、吗啡用量以及拟精神病性副作用/幻觉的发生率。两篇论文报告了呼吸功能的测量结果。该证据表明，在吗啡PCA中添加氯胺酮是安全的，据报告需要干预的幻觉发生率为2.9%，一项荟萃分析发现所有中枢神经系统副作用的发生率为18%，而单纯使用吗啡时为15%，P = 0.31，相对危险度为1.27，95%置信区间为（0.8 - 2.01）。其在胸外科手术后使用的所有随机对照试验均未发现幻觉或心理副作用。胸外科的所有五项研究（n = 243）均发现PCA-MK可减少吗啡需求量。胸外科手术论文中PCA-MK患者的疼痛评分显著更低，有一篇论文还报告患者满意度提高。然而，在对五篇在各种手术环境中研究PCA-MK的论文进行的荟萃分析中未发现显著改善。两篇报告呼吸结局的论文均发现胸外科手术后PCA-MK患者的氧饱和度和动脉血二氧化碳分压（PaCO₂）水平有所改善。我们得出结论，在吗啡PCA中添加低剂量氯胺酮是安全的，开胸术后可能比单纯使用吗啡PCA（PCA-MO）提供更好的疼痛控制，可减少吗啡用量并可能改善呼吸功能。因此，这些研究支持常规使用PCA-MK而非PCA-MO来改善开胸术后的疼痛控制。
