Perioperative management of the child on long-term opioids

The strategies used to manage children exposed to long-term opioids are extrapolated from adult literature. Opioid consumption during the perioperative period is more than three times that observed in patients not taking chronic opioids. A sparing use of opioids in the perioperative period results in both poor pain management and withdrawal phenomena. The child's pre-existing opioid requirement should be maintained, and acute pain associated with operative procedures should be managed with additional analgesia. This usually comprises short-acting opioids, regional or local anesthesia, and adjuvant therapies. Long-acting opioids, transdermal opioid patches, and implantable pumps can be used to maintain the regular opioid requirement. Intravenous infusion, nurse controlled analgesia, patient-controlled analgesia, or oral formulations are invaluable for supplemental requirements postoperatively. Effective management requires more than simply increasing opioid dose during this time. Collaboration of the child, family, and all teams involved is necessary. While chronic pain or palliative care teams and other staff experienced with the care of children suffering chronic pain may have helpful input, many pediatric hospitals do not have chronic pain teams, and many patients receiving long-term opioids are not palliative. Acute pain services are appropriate to deal with those on long-term opioids in the perioperative setting and do so successfully in many centers. Staff caring for such children in the perioperative period should be aware of the challenges these children face and be educated before surgery about strategies for postoperative management and discharge planning.     

Opioid therapy of chronic pain: Assessment of consequences

This paper will review what is known about key issues of importance in the clinical use of opioids for the treatment of intractable non-cancer related pain, and will attempt to describe the evolving areas of consensus among clinicians who treat pain and addiction regarding various aspects of use of opioids for the treatment of chronic non-cancer pain.     

Epidural and intrathecal analgesia for cancer pain

The three-step analgesic ladder approach developed by the World Health Organization works well in treating the vast majority (70–90%) of patients suffering from pain related to cancer. In those patients who do not get pain relief by this three-step approach, intraspinal agents can be a fourth step in managing pain of malignant origin. Although morphine is the only opioid approved by the US Food and Drug Administration for intraspinal use, many different opioid analgesics are used intraspinally, including hydromorphone, fentanyl, sufentanil, meperidine and methadone in the treatment of cancer pain. Many non-opioid agents have also been used intraspinally either alone or in combination with opioids in the treatment of intractable cancer pain. This chapter summarizes the clinical use of these agents with some practical points.     

Preemptive Analgesia With Oxycodone Is Associated With More Pain Following Total Joint Arthroplasty

BackgroundPreemptive multimodal analgesia (PMA) is a commonly used technique to control pain following total joint arthroplasty. PMA protocols use multiple analgesics immediately preoperatively to prevent central sensitization and amplification of pain during surgery. While benefits of some individual components of a PMA protocol have been established, there are little data to support inclusion or exclusion of opioids in this context.MethodsThis is a retrospective cohort study of 550 patients undergoing elective, primary total joint arthroplasty at a single institution using a standardized preoperative perioperative protocol. Two hundred seventy-five patients received oxycodone in addition to a standard multimodal preoperative analgesia regimen just before surgery and were compared to a matched cohort of 275 patients who received the standard regimen alone. Outcome measures included inpatient visual analog scale pain scores, inpatient opioid consumption, length of stay, and ambulation distance with physical therapy.ResultsPatients who received opioids in preoperative holding reported significantly greater visual analog scale pain scores on postoperative day 1 (3.7 vs 3.1; P = .01), when compared to those who did not. These patients also walked shorter distances on postoperative day 0 (59.5’ vs 125.7’; P < .001) and consumed greater morphine equivalents per hospital day over the course of their hospital stay (52.2 vs 37.2 mg; P < .001). These differences remained significant when stratified by procedure, total knee arthroplasty or total hip arthroplasty. Differences in pain and function between groups were more pronounced in patients undergoing total hip arthroplasty than those undergoing total knee arthroplasty.ConclusionTotal joint patients who were given preemptive opioids immediately before surgery experienced more pain, consumed more postoperative opioids, and exhibited impaired early function as compared to those who were not given preemptive opioids. Orthopedic surgeons should reconsider routine use of preemptive opioids in this context.     

Opioid responsiveness

Cancer pain generally responds in a predictable way to analgesic drugs and drug therapy is the mainstay of treatment. A small proportion of patients, of the order of 20%, have pain that does not respond well to conventional analgesic management. Because opioid analgesics are the most important part of this pharmacological approach, a terminology has developed which centres around whether or not pain will respond to opioid analgesics. The terms opioid-responsive-pain and opioid-non-responsive pain, or opioid-resistant-pain, have been used to differentiate between patients whose pain falls into these two broad groups. This terminology is not satisfactory because it implies an all or none phenomenon, that is that pain either does or does not respond to opioid analgesics. Rarely is there such a clear distinction in practice. This is because the end point when titrating dose against pain with strong opioid analgesics is not simply pain relief or lack of relief: adverse effects may limit dose titration. It is preferable to describe patients with pain which is relatively less sensitive to opioids and/or patients where there is an inbalance between analgesia and unwanted effects as having “opioid-poorly-responsive pain”. A pragmatic definition of opioid-poorly-responsive pain is pain that is inadequately relieved by opioid analgesics given in a dose that causes intolerable side effects despite routine measures to control them. Included in this definition is so called paradoxical pain which is not a distinct entity. Neuropathic pain is the most common form of opioid-poorly-responsive pain. The underlying pathophysiology remains unclear but abnormal metabolism of morphine is not the cause of a poor response to this drug. Patients with opioid-poorly-responsive-pain should be considered for treatment with the same opioid by an alternative (spinal) route or with an alternative opioid agonist administered by the same route (whether oral or parenteral), in conjunction with adjuvant analgesics such as tricyclic antidepressants. The most commonly used alternative oral opioids are phenazocine and methadone; transdermal fentanyl is an additional option.     

An audit of pain and vomiting in paediatric day case surgery

Three hundred and thirteen paediatric day case patients were prospectively audited to assess postoperative pain, nausea and vomiting using data sheets completed by nursing staff, anaesthetists and parents. The incidence of nausea and vomiting was 7.3% and was commoner in older children and those who had received opioids. Forty per cent of patients had some degree of postoperative pain; 17% of these patients were scored as having severe pain. Of children who had pain on returning home (31.4%), 85% of these required paracetamol. Fifteen per cent of children had a disturbed night due to pain and/or vomiting after their operation and 28.5% of children had pain on the following day. Boys undergoing circumcision were responsible for a disproportionately high percentage of the severe pain scores. Audit has helped to highlight deficiencies in the service provided and has led staff to try and improve their methods of analgesia.     

神经病理性疼痛中阿片类药物的应用

阿片类药物作为一种较为有效的药物用来治疗重度疼痛以及包括神经病理性疼痛在内的慢性疼痛.然而在神经病理性疼痛中,阿片类药物的疗效存在争议.长期持续的运用阿片类药物容易产生耐受的现象,表现为需要增加药物剂量来维持疼痛的缓解程度.但最近的几个研究都表明阿片类药物在神经病理痛中的应用是有效的.现就神经病理性疼痛中阿片类药物的耐受及应用发展作一阐述.     

Use of Chronic Methadone Before Total Knee Arthroplasty

Background

A subset of patients who undergo total knee arthroplasty (TKA) are on methadone maintenance. They require more and often unpredictable quantities of opioids to function as effective painkillers. This study aims to compare the opioid requirements and the immediate postoperative course for patients on methadone maintenance with those who are not, after a TKA.

Orale Opioide zur Langzeittherapie chronischer Nicht-Tumorschmerzen

The treatment of cancer pain with opioids is well accepted. However, the use of opioids for the treatment of non-cancer pain is still a matter of controversy. The main matters of concern are physical dependence and opioid abuse. Another argument against opioids is the lack of efficacy. Experiences with opioids in non-cancer pain have been published on about 850 patients, the longest therapy lasting almost 14 years. 85% of the patients treated with opioids had beneficial effects. In a number of investigations evaluating the opioid sensibility of pain by PCA and intravenous infusions, 67–80% of the patients with neuropathic pain responded to opioids. The efficacy of opioids in the treatment of non-cancer pain was proven in 3 placebo controlled studies. In 2 studies pain reduction in neuropathic pain was similar to that in nociceptive pain. When opioids are used, the administration has to be performed according to well defined standards. The indication for opioids must be made by a specialist in pain management. The diagnosis must clearly reveal an organic origin of the pain. Before the start of therapy the duration as well as the criteria for discontinuation must be set up. The treatment must be controlled by a specialist team and frequent regular follow up investigations must be performed. These must include proper documentation of the pain level, changes in patients' function and in social activities. The reliable intake of prescribed medication must be assured if necessary by laboratory screening. The treatment of non-cancer pain with opioids may be an alternative for those patients, who didn't gain sufficient reduction of pain by other therapies. Standards for this therapy are an absolute necessity and are to be followed closely.     

Indications for neurosurgical treatment of chronic pain

Summary Guidelines are presented for the neurosurgical treatment of chronic pain. In these guidelines a distinction is made between the pain of cancer and neurogenic pain. In cancer pain the survival time and the location of the lesion are the important guidelines. Possible procedures are: opioids via CSF route, lesions in nociceptive pathways and PV-PAG stimulation of the thalamus. In neurogenic pain, neurostimulation procedures, tailored to the location of the pain are procedures of first choice. There are however specific indications for other procedures depending on the aetiology of the pain. Causalgia and reflex sympathetic dystrophy: sympathetic blocade; Tic douloureux: radio-frequency lesion, glycerol, balloon inflation of the ganglion of Gasser, and microvascular decompression; Plexus avulsion: dorsal root entry zone lesion (D.R.E.Z.).There is a need for controlled prospective neurosurgical trials in which as a minimal rule an independent party should evaluate the results of the surgical procedure.Invited Lecture, presented at the European Congress of Neurosurgery, Moscow, June 23–29, 1991.     

疼痛敏感性及阿片类镇痛药用量与多巴胺转运体基因多态性的相关性

目的探讨多巴胺转运体(dopamine transporter, DAT)基因(DAT1)多态性对疼痛敏感性及阿片类镇痛药用量的影响。方法选择择期上腹部手术的汉族患者121例,抽取患者外周静脉血通过聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术检测DAT1可变串联重复(VNTR)多态性,利用便携式压力测试仪对患者试验性疼痛压力痛阈(PPT)和压力耐痛阈(PTO)进行检测,记录患者术后阿片类镇痛药用量,分析患者的生物社会学特征和DAT1 VNTR多态性与疼痛敏感性和术后阿片类镇痛药用量的关系。结果 121例患者中,DAT1 VNTR等位基因的分布频率分别为9R(18.2%)、10R(81.8%),基因型分布频率分别为9R/9R(7.4%)、9R/10R(21.5%)、10R/10R(71.1%)。不同DAT1 VNTR等位基因型患者PPT和PTO差异无统计学意义,术后24 h和48 h阿片类药物用量差异无统计学意义。不同DAT1 VNTR等位基因型患者中,40岁以下患者的PTO明显高于65岁以上的患者(P0.05),阿片类镇痛药用量明显多于65岁以上患者(P0.05)。结论 DAT1 VNTR多态性可能与疼痛敏感性及术后阿片类镇痛药用量无关。     

Naloxone Does Not Reverse the Pain-Reducing Effect of Vibratory Stimulation

Fifteen patients suffering from chronic epicondylitis pain who obtained alleviation of pain with vibratory stimulation were studied to investigate the possible role of endogenous opioids in the mediation of pain alleviation of vibratory stimulation. The patients' subjective pain intensity was rated using a graphic rating scale. In five patients the changes in peripheral blood flow before, during and after vibratory stimulation were also studied. After 30 min of mechanical vibratory stimulation at 100 Hz, patients were given a double-blind intravenous injection of naloxone or saline (placebo). Twelve patients did not experience reversal of pain relief from naloxone (0.4 mg). Reversal of the pain alleviation induced by vibratory stimulation was seen in two patients after i.v. injections of naloxone and in one patient after i.v. injections of naloxone or saline. When an i.m. injection of naloxone 0.01 mg/kg was administered before and during vibratory stimulation, none of the patients experienced an antagonistic effect of the pain-reducing effect of vibratory stimulation. The results suggest that the pain relief obtained with vibratory stimulation at 100 Hz is not associated with release of endogenous opioids.     

Breakthrough pain in opioid-treated chronic non-malignant pain patients referred to a multidisciplinary pain centre: a preliminary study

BACKGROUND: Breakthrough pain (BTP) has not formerly been discussed as such in chronic non-malignant pain patients referred to pain centres and clinics. The purpose of the study was to investigate the prevalence, characteristics and mechanisms of BTP in opioid-treated chronic non-malignant pain patients referred to a pain centre and to assess the short-term effects of pain treatment. METHODS: Patients were assessed at referral (T(0)) and after a treatment period of 3 months (T(3)) using the visual analogue scale (VAS) of the brief pain inventory (BPI) within somatic nociceptive, neuropathic and/or visceral pain conditions, the mini mental state examination (MMSE) and the hospital anxiety and depression scale (HADS). The main treatment intervention from T(0) to T(3) was to convert short-acting oral opioids to long-acting oral opioids and to discontinue on demand and parenteral use of opioids. RESULTS: Thirty-three patients were assessed at T(0) and 27 at T(3). The prevalence of BTP declined significantly from T(0) (90%) to T(3) (70.4%). Worst, least, average and current pain intensities as well as duration of BTP were significantly reduced from T(0) to T(3.) The majority of BTPs were exacerbation of background pain assumed to be of the same pain mechanisms. High average pain intensity (BPI) was significantly associated with high scores for both anxiety and depression (HADS). CONCLUSION: BTP in chronic non-malignant pain patients seems to be surprisingly frequent and severe. Stabilizing the opioid regimen seems to reduce pain intensity in general as well as the intensity and duration of BTP. Average pain intensity was associated with anxiety and depression.     

Clinical experience of long–term treatment with epidural and intrathecal opioids – a nationwide survey

Long–term use of spinal opioids to treat chronic severe pain is widely established. However, the indications, shortcomings and complications of the method have not been completely described. Experience with spinal opioids was analysed for the period 1979–1984 in a nationwide Swedish survey. Out of 93 anaesthesia departments, 69 used the method. Approximately 750 patients were treated with epidural morphine for an average duration of 124 days (3–450). Eighteen patients were treated with intrathecal morphine for an average period for 47 days (3–90). The intrathecal approach was used in all clinics because of failure of the epidural route. In only one department was the intrathecal approach used as the primary route of therapy, depending on the mechanism of pain. The highest daily morphine dose was 480 mg and 50 mg for epidural and intrathecal routes, respectively. The patients given the highest dosages were not necessarily those subjected to the longest treatment. The need for increased dosage seems to be related not only to changes in receptor sensitivity but also to changes in pain mechanisms. No case of threatening ventilatory depression was reported. Thirty–two departments had treated a few patients with chronic non–cancer pain conditions. Initial results were considered "excellent" in H departments, but at follow–up results were excellent in only one department. In addition to dislocation, occlusion of the catheters or leakage, injection pain was an obstacle to successful treatment. Pruritus, urinary retention, and local infections were not reported as significant problems, but one case of meningitis was reported.