Extradural and parenteral pethidine as analgesia after total hip replacement: effects and kinetics. A controlled clinical study

Neuraxial blockade for the prevention of postoperative mortality and major morbidity: an overview of Cochrane systematic reviews

BACKGROUND

Various beneficial effects derived from neuraxial blocks have been reported. However, it is unclear whether these effects have an influence on perioperative mortality and major pulmonary/cardiovascular complications.

OBJECTIVES

Our primary objective was to summarize Cochrane systematic reviews that assess the effects of neuraxial blockade on perioperative rates of death, chest infection and myocardial infarction by integrating the evidence from all such reviews that have compared neuraxial blockade with or without general anaesthesia versus general anaesthesia alone for different types of surgery in various populations. Our secondary objective was to summarize the evidence on adverse effects (an adverse event for which a causal relation between the intervention and the event is at least a reasonable possibility) of neuraxial blockade. Within the reviews, studies were selected using the same criteria.

METHODS

A search was performed in the Cochrane Database of Systematic Reviews on July 13, 2012. We have (1) included all Cochrane systematic reviews that examined participants of any age undergoing any type of surgical (open or endoscopic) procedure, (2) compared neuraxial blockade versus general anaesthesia alone for surgical anaesthesia or neuraxial blockade plus general anaesthesia versus general anaesthesia alone for surgical anaesthesia and (3) included death, chest infection, myocardial infarction and/or serious adverse events as outcomes. Neuraxial blockade could consist of epidural, caudal, spinal or combined spinal-epidural techniques administered as a bolus or by continuous infusion. Studies included in these reviews were selected on the basis of the same criteria. Reviews and studies were selected independently by two review authors, who independently performed data extraction when data differed from one of the selected reviews. Data were analysed by using Review Manager Version 5.1 and Comprehensive Meta Analysis Version 2.2.044.

MAIN RESULTS

Nine Cochrane reviews were selected for this overview. Their scores on the Overview Quality Assessment Questionnaire varied from four to six of a maximal possible score of seven. Compared with general anaesthesia, neuraxial blockade reduced the zero to 30-day mortality (risk ratio [RR] 0.71, 95% confidence interval [CI] 0.53 to 0.94; I(2) = 0%) based on 20 studies that included 3006 participants. Neuraxial blockade also decreased the risk of pneumonia (RR 0.45, 95% CI 0.26 to 0.79; I(2) = 0%) based on five studies that included 400 participants. No difference was detected in the risk of myocardial infarction between the two techniques (RR 1.17, 95% CI 0.57 to 2.37; I(2) = 0%) based on six studies with 849 participants. Compared with general anaesthesia alone, the addition of a neuraxial block to general anaesthesia did not affect the zero to 30-day mortality (RR 1.07, 95% CI 0.76 to 1.51; I(2) = 0%) based on 18 studies with 3228 participants. No difference was detected in the risk of myocardial infarction between combined neuraxial blockade-general anaesthesia and general anaesthesia alone (RR 0.69, 95% CI 0.44 to 1.09; I(2) = 0%) based on eight studies that included 1580 participants. The addition of a neuraxial block to general anaesthesia reduced the risk of pneumonia (RR 0.69, 95% CI 0.49 to 0.98; I(2) = 9%) after adjustment for publication bias and based on nine studies that included 2433 participants. The quality of the evidence was judged as moderate for all six comparisons.No serious adverse events (seizure or cardiac arrest related to local anaesthetic toxicity, prolonged central or peripheral neurological injury lasting longer than one month or infection secondary to neuraxial blockade) were reported. The quality of the reporting score of complications related to neuraxial blocks was nine (four to 12 (median range)) of a possible maximum score of 14.

AUTHORS' CONCLUSIONS

Compared with general anaesthesia, a central neuraxial block may reduce the zero to 30-day mortality for patients undergoing surgery with intermediate to high cardiac risk (level of evidence, moderate). Further research is required.

A procedure-specific systematic review and consensus recommendations for analgesia after total hip replacement

Total hip replacement is a major surgical procedure usually associated with significant pain in the early postoperative period. Several anaesthetic and analgesic techniques are in common clinical use for this procedure but, to date, clinical studies of pain after total hip replacement have not been systematically assessed. Using the Cochrane protocol, we have conducted a systematic review of analgesic, anaesthetic and surgical interventions affecting postoperative pain after total hip replacement. In addition to the review, transferable evidence from other relevant procedures and clinical practice observations collated by the Delphi method were used to develop evidence-based recommendations for the treatment of postoperative pain. For primary total hip replacement, PROSPECT recommends either general anaesthesia combined with a peripheral nerve block that is continued after surgery or an intrathecal (spinal) injection of local anaesthetic and opioid. The primary analgesic technique should be combined with a step-down approach using paracetamol plus conventional non-steroidal anti-inflammatory drugs, with strong or weak opioids as required.

Epidural analgesia for pain relief following hip or knee replacement

BACKGROUND

Hip and knee replacement are common operative procedures to improve mobility and quality of life. Adequate pain relief is essential in the postoperative period to enable ambulation and initiation of physiotherapy. Lumbar epidural analgesia is a common modality for pain relief following these procedures. However, there is no systematic review of the evidence comparing the efficacy of epidural analgesia with other postoperative analgesic modalities. As the use of epidural analgesia may delay the initiation of anticoagulant thromboprophylaxis due to the potential risk of epidural hematoma, a synthesis of the evidence is necessary to determine whether or not alternative analgesic modalities are worse, equivalent, or better than epidural analgesia.

OBJECTIVES

Our objective is to answer the question: "Is lumbar epidural analgesia more efficacious than systemic analgesia or long-acting spinal analgesia for postoperative pain relief in patients after elective hip or knee replacement?"

SEARCH STRATEGY

MEDLINE, EMBASE, CINAHL, LILACS, and the Cochrane Controlled Trials Register were searched from their inception to June 2001. Reference lists of review articles and included studies were also reviewed for additional citations.

SELECTION CRITERIA

A study was included if it was a randomized or pseudo randomized controlled clinical trial of patients undergoing hip or knee replacement, in which postoperative lumbar epidural analgesia was compared to other methods for pain relief. Study selection was performed unblinded in duplicate.

DATA COLLECTION AND ANALYSIS

Data were collected unblinded in duplicate. Information on the patients, methods, interventions, outcomes (pain relief, postoperative function, length of stay) and adverse events were recorded. Methodological quality was assessed using a validated 5-point scale. Meta-analysis was conducted when sufficient data existed from two or more studies. Heterogeneity testing was performed using the Breslow-Day method. The fixed effects model was used unless heterogeneity was present, in which case, a random effects model was used. Continuous data were summarized as weighted mean differences (WMD) or standardized mean differences (SMD) with 95% confidence intervals (CI). Dichotomous data were summarized as odds ratios (OR) and numbers-needed-to-treat (NNT) or numbers-needed-to-harm (NNH) with their respective 95% CI. Graphical representation of continuous data used the MetaView program.

MAIN RESULTS

In the first four to six hours after surgery, patients receiving epidural analgesia had less pain at rest, based on visual analog scores (VAS), than patients receiving systemic analgesia (SMD -0.77; 95% CI -1.24 to -0.31). This effect was not statistically significant by 18 to 24 hours (SMD -0.29; 95% CI -0.73 to 0.16). These observations were based only on studies evaluating populations consisting of total knee replacements alone or mixed populations of total hip or total knee replacements. For pain relief with movement after surgery, patients receiving epidural analgesia reported lower pain scores than patients receiving systemic analgesia in all four studies examining these outcomes. The choice of epidural agents may also influence the extent to which epidural analgesia differs from systemic analgesia. The differences between epidural analgesia and systemic analgesia in the frequency of nausea and vomiting (OR 0.95; 95% CI 0.60 to 1.49) or depression of breathing (OR 1.07; 95% CI 0.45 to 2.54) were not statistically significant. Sedation occurred less frequently with epidural analgesia (OR 0.30; 95% CI 0.09 to 0.97) with a number-needed-to-harm of 7.7 (95% CI 3.5 to 42.0) patients for the systemic analgesia group. Retention of urine (OR 3.50, 95% CI 1.63 to 7.51; NNH 4.5, 95% CI 2.3 to 12.2), itching (OR 4.74, 95% CI 1.76 to 12.78; NNH 6.8, 95% CI 4.4 to 15.8), and low blood pressure (OR 2.78, 95% CI 1.15 to 6.72; NNH 6.7, 95% CI 3.5 to 103) were more frequent with epidural analgesia compared to systemic analgesia. There were insufficient numbers to draw conclusions on the edural analgesia compared to systemic analgesia. There were insufficient numbers to draw conclusions on the effect of epidural analgesia on serious postoperative complications, functional outcomes, or length of hospital stay.

REVIEWER'S CONCLUSIONS

Epidural analgesia may be useful for postoperative pain relief following major lower limb joint replacements. However, the benefits may be limited to the early (four to six hours) postoperative period. An epidural infusion of local anesthetic or local anesthetic-narcotic mixture may be better than epidural narcotic alone. The magnitude of pain relief must be weighed against the frequency of adverse events. The current evidence is insufficient to draw conclusions on the frequency of rare complications from epidural analgesia, postoperative morbidity or mortality, functional outcomes, or length of hospital stay.

Single dose oxycodone and oxycodone plus paracetamol (acetominophen) for acute postoperative pain

BACKGROUND

Oxycodone is a strong opioid agonist which is useful for the management of severe pain. It is becoming increasingly important to assess the relative efficacy and harm caused by different treatments. This can be determined when an analgesic is compared with control under similar clinical circumstances.

OBJECTIVES

To quantitatively assess the analgesic efficacy and adverse effects of single-dose oxycodone and oxycodone plus paracetamol in randomised trials in acute postoperative pain.

SEARCH STRATEGY

Published reports were identified from Medline, Biological Abstracts, Embase, the Cochrane Library and the Oxford Pain Relief Database. Additional studies were identified from the reference lists of retrieved reports.

SELECTION CRITERIA

The inclusion criteria were: full journal publication, clinical trial, random allocation of adult patients to treatment groups, double blind design, moderate to severe baseline pain, postoperative administration of study drugs, treatment arms which included oxycodone or oxycodone plus paracetamol and placebo (or active control for which comparable efficacy data exist), and oral, intramuscular or intravenous administration of study drugs.

DATA COLLECTION AND ANALYSIS

Summed pain intensity and pain relief data over 4-6 hours were extracted and converted into dichotomous information yielding the number of patients obtaining at least 50% pain relief. Estimates of relative benefit and number-needed-to-treat were calculated. Single-dose adverse effect data were collected.

MAIN RESULTS

Seventy-seven reports were identified. Seven reports met the inclusion criteria; all assessed oral oxycodone. For efficacy, a significant benefit of active drug over placebo was shown for all doses of oxycodone and oxycodone plus paracetamol, except oxycodone 5 mg. For adverse effects, the number of patients reporting adverse effects was extracted for each dose of active drug versus placebo. When these data were pooled for the individual doses significantly more adverse effects with active drug than with placebo were shown for all doses, except oxycodone 5 mg and its combination with paracetamol 325 mg. This was also shown for drowsiness/somnolence. Significantly more nausea, vomiting and dizziness/lightheadedness were reported with oxycodone 10 mg plus paracetamol (650 mg and 1000 mg) than with placebo.

REVIEWER'S CONCLUSIONS

Single-dose oral oxycodone, with or without paracetamol, appears to be of comparable efficacy to intramuscular morphine and non-steroidal anti-inflammatory drugs. Central nervous system adverse effects were common.

Epidural pethidine: pharmacology and clinical experience

Pethidine is an effective epidural opioid for the treatment of acute pain. Its use has been well described in Australian and New Zealand practice, particularly in the field of obstetric anaesthesia. Reported methods of delivery have included bolus injection, continuous infusion and patient-controlled epidural analgesia. Areas of application have included treatment of postoperative pain, labour pain and intraoperative pain. Because of its intermediate lipid solubility, pethidine may have advantages over many other epidural opioids. However, potential for accumulation of norpethidine limits its use to relatively short durations of treatment.

Epidural complications and a case of malignant meningitis

We report a case in which the signs of a malignant meningitis could have been confused with complications of an in-dwelling epidural catheter which was being used for analgesia. This confusion could have had disastrous implications for the patient's pain relief. We also discuss some of the issues and problems surrounding the use of in-dwelling epidurals in terminal care patients.

The relationship between the pharmacokinetics and pharmacodynamics of spinal opioids. Minireview based on a doctoral thesis

Spinal opioids have been used clinically since the late seventies to treat acute, traumatic, obstetric and chronic pain. In this article the influence of the pharmacokinetics on the dynamics of intrathecal and epidural opioid administration are discussed with reference to current knowledge.

CSF and plasma pharmacokinetics of pethidine and norpethidine in man after epidural and intrathecal administration of pethidine

The disposition of pethidine and its main metabolite, norpethidine, in cerebrospinal fluid (CSF) and plasma was studied in 11 thoracic surgery patients after lumbar epidural (100 mg; n = 6) or lumbar intrathecal (25 mg; n = 5) administration of pethidine. Pethidine appeared more slowly in plasma after intrathecal than after epidural administration (tmax 2.3 h and 14 min, respectively), but systemic bioavailability was similar. The CSF concentrations of pethidine were higher than those in plasma after both routes of administration. The maximal CSF/plasma concentration ratio was 6000 to 45,000 after intrathecal administration but was only 26 to 97 after the epidural route. Pethidine was rapidly distributed in CSF; nine to ten h after the intrathecal and epidural injections the CSF/plasma concentration ratios were 12 to 89 and 2 to 33, respectively. The calculated bioavailability in CSF of epidural pethidine was 10.3%. The terminal elimination half-life of pethidine was 6.0 h (CSF) and 5.4 h (plasma) after intrathecal administration and 8.6 h (CSF) and 8.8 h (plasma) after epidural injection. The volume of distribution of unchanged pethidine in the subarachnoid space was 13 ml.kg-1 and clearance from the CSF was 15 microliters.kg-1.min-1. In all patients receiving intrathecal pethidine and in some patients after epidural pethidine, CSF norpethidine concentrations were higher than those in plasma; the maximum CSF norpethidine was 102 to 1211 ng.ml-1 and 14 to 210 ng.ml-1 and the maximum CSF/plasma norpethidine concentration ratios were 21 to 652 and 0.6 to 14 times after intrathecal and epidural administration, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)