Innovations in postoperative pain management: continuous infusion of local anesthetics

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PATIENTS AND HEALTH CARE PROVIDERS alike struggle with alleviating postoperative pain. Patients with unrelieved pain are less likely to cough, breathe deeply, or move easily after surgery, which adversely affects their recovery.

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INNOVATIONS IN TECHNOLOGY, such as continuous infusion of local anesthetics, have revolutionized postoperative pain management. Technological improvements in needles, catheter insertion techniques, and effortless drug delivery systems are facilitating prolonged analgesia with few adverse effects, increasing patient satisfaction, and expediting postoperative recovery. AORN J 85 (May 2007) 904-914. © AORN, Inc, 2007.

     

The effect of pH-adjusted 2-chloroprocaine on the duration and quality of pain relief with a subsequent continuous epidural bupivacaine infusion.

A randomized, double-blind true experimental design with a post-test only was chosen to determine if the addition of sodium bicarbonate to 2-chloroprocaine would result in a longer duration of epidural analgesia, as well as increase the quality of pain relief in stage I parturients receiving a continuous bupivacaine epidural infusion. The experimental group (number (N) = 16) received sodium bicarbonate and 2-chloroprocaine followed by a continuous bupivacaine epidural infusion. The control group (N = 15) received normal saline and 2-chloroprocaine followed by a continuous bupivacaine epidural infusion. Only ASA I or II patients in stage I labor were included in this study. Measures of pain perception were made using a self-report, visual analog scale. Measures also were made of the quality and duration of block over time, the intensity of motor block over time, and the blood pressure over time. The cephalad dermatome level of analgesia was determined by pinprick. A record of the need for a supplemental bolus of local anesthetic to maintain a sensory level of T-10 was also recorded. The mean self-perceived level of pain was significantly different for the two groups (P = .024). Moreover, the pattern of self-perceived level of pain over time differs for the two groups in a significant way (P = .023). Additional bolus injections occurred nine times in the control group and six times in the experimental group. The differences were not found to be significant (P > .106). The differences in time and amount of local anesthetic delivered were also found to be trivial (P > .80).(ABSTRACT TRUNCATED AT 250 WORDS)     

How pharmacokinetic can help to choose the right local anesthetics during epidural infusion

Local anesthetics (LA) are used for the prevention and relief of both acute and chronic pain. The local anesthetic molecule consists of three components; each of these contributes distinct properties to the molecule. The onset of action is determined by tissue pH, the pKa of the particular agent used, and the amount of nonionized drug available in the tissue. The duration of action depends on the length of time that the drug binds to the membrane. Most local anesthetics were produced as enantiomeric mixtures known as racemates, although it is recognized that each enantiomer possesses quite different pharmacological properties. All amide-type local anesthetics, except for lidocaine, contain a chiral center, meaning that two enantiomers exist. Enantiomers have the same physicochemical properties and differ only in the way that they rotate plane-polarized light. However, their biological behavior, in terms of pharmacokinetic and pharmacodynamic characteristics, can be very different. The clinical response to a particular local anesthetic or its toxicity may vary substantially from patient to patient; dosing often requires careful titration. Interindividual variability is caused by several factors including the pharmacokinetics features of the drug, pharmacodynamic properties or patient’s characteristics.     

Epidural fentanyl by continuous infusion for relief of postoperative pain

Data from the charts of 40 patients in whom a continuous epidural infusion of fentanyl had been used to effect postoperative pain relief were retrospectively reviewed. Of these patients, 39 out of 40 (97.5%) reported adequate analgesia at an average fentanyl infusion rate of 1.3 micrograms/kg/h. After discharge from the postanesthesia recovery room, each patient was sent to a general medical-surgical nursing floor with standard orders for medications to be administered as required. The overall incidence of side effects was low, and, in particular, respiratory depression was not noted. In our experience, this analgesia technique is safe, effective, and could be readily introduced into most community hospital settings.     

Prolonged epidural analgesia with ultracaine for labor pain relief

Prolonged epidural analgesia (PEA) for labor pain relief and effect of this method of conduction blockade on the main vital systems of mother and newborn were studied. PEA with ultracain was used in 486 women aged 18-38 years. Puncture and catheterization of the epidural space was made at the level of the second-third lumbar vertebrae; a single dose of 1% ultracain was 1.0-1.2 mg/kg. Effects of this method on the hemodynamics, external respiration function, autonomic status, and newborn status were evaluated. PEA with ultracain proved to be highly effective and safe for the mother and exerted no depressive effect on the newborn. Positive characteristics of ultracain are the minimum latent period, long (86.8 +/- 5.1 min) duration of sensory blocking, and no side effects.     

Comparison of intermittent bolus with continuous infusion of epidural morphine in the treatment of severe cancer pain.

Twenty-eight patients with severe pain due to cancer, who could no longer obtain acceptable pain relief from optimised doses of oral opioids, were entered into a study which compared pain relief, satisfaction with pain therapy and estimates of neuropsychological functioning during treatment with spinally administered (i.e., epidural and intrathecal) morphine as either repeated bolus doses or as a continuous infusion. These measures of efficacy and side effects were repeated every 2 weeks until either the patient died (82% of patients), withdrew from the study or were no longer able to complete the tests due to deterioration of their condition. The mean (range) duration of treatment was 169 (6-537) days for those patients receiving continuous infusion and 140 (28-378) days for those patients receiving repeated bolus doses. There was no significant difference in visual analogue pain scores, pain relief scores and satisfaction scores between the bolus and infusion groups. Furthermore, low pain scores and high pain relief scores indicated that both treatment modalities provided effective pain control. Similarly, there was no significant difference between the two groups in the various tests used to assess depression or neuropsychological function (i.e., memory, vigilance, attention and processing). There was a significantly greater degree of dose escalation in patients receiving continuous infusion compared to patients receiving repeated bolus doses. For 6 patients in the infusion group the catheter was sited in the intrathecal space, as the dose requirements by the epidural route exceeded the delivery capacity of the pump. For 4 patients in the bolus group the catheter was similarly sited, due to pain on injection and leakage/blockage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contamination of bags for continuous epidural infusion

A prospective study was conducted firstly to determine whether the use of an epidural infusion posed an infection risk, and secondly how often the epidural infusion set should be changed when used for short term postoperative pain relief. Eighty-nine patients were studied over a six-month period. The epidural catheter tips (EC) and infusion were cultured. The mean duration of the epidural infusion was 4.3 days (SD 1.65). Fifty-one males and 38 females were recruited with an average age of 70.5 years (SD 9.80); 43 patients had a single bag change and 46 had no bag change. Three times Staphylococcus epidermidis and once Streptococcus viridans were cultured from epidural fluid. Thirty-nine patients grew micro-organisms in EC tips, 31 common skin flora and eight unexpected organisms eg Acinetobacter species (n=5), MRSA (n=1), coliform (n=1 unspecified), Citrobacter species (n=1). No patient developed local or systemic signs of infection related to the device and there was no relationship between the duration of the infusion and systemic infection related to the device. The results suggest that the routine changing of sets after a single bag change is unjustified.     

Postoperative epidural analgesia using local anesthetics in combination with morphine in children

Epidural analgesia with lidocaine (trimecaine) in combination with the minimum morphine doses is an effective method for regional pain relief in children. It maintains a long postoperative analgesia with 5-10 times lower doses of narcotics.     

Haemodynamic, endocrine and nociceptive response to gynaecological procedures under epidural local anaesthesia during continuous epidural infusion or bolus epidural fentanyl dosing

This study aimed to evaluate the analgesic effects and hormonal responses of a single epidural bolus compared to continuous epidural infusion of fentanyl as supplements to intraoperative local epidural anaesthesia for major gynaecological surgery. Forty patients undergoing total vaginal hysterectomy were randomised to receive in a double blind fashion either 1.5 μg kg⁻¹ fentanyl epidurally (group A) or saline (group B) as bolus injections followed by epidural infusion of saline or fentanyl (0.7 μg kg⁻¹h⁻¹) respectively at a rate of 10 ml h⁻¹. Postoperative pain intensity was assessed by visual analogue scale (VAS). Prolactin and cortisol plasma levels were used as stress markers. The onset of anaesthesia was significantly shorter in group A (p<0.05) but the duration of T₁₀ blockade was significantly longer in group B (p<0.01). Pain intensity was significantly higher in group A at 90, 105 and 120 minutes after skin incision (p<0.001). There was no intraoperative difference in heart rate or mean arterial pressure between the two groups nor was there any difference in the incidence of adverse effects such as nausea, vomiting or shivering. Both groups had a progressive decrease in serum cortisol and prolactin concentrations 30 and 60 min after skin incision, but cortisol and prolactin concentrations were higher in group A (p<0.05) 120 minutes after skin incision.Our observations suggest that perioperative continuous epidural infusion of fentanyl begun intraoperatively attenuates the endocrine stress response, but a bolus dose of fentanyl given along with bupivacaine lacks this protective effect. A possible explanation for these findings is that an infusion begun intraoperatively, just after administration of epidural bupivacaine, prolongs the duration of sensory blockade and provides a better quality of analgesia, and thereby attenuates the endocrine response triggered by regression of the intraoperative level of anaesthesia.     

利多卡因缓解静脉输液中疼痛的效果观察

目的：探讨2％盐酸利多卡因注射液在静脉输液穿刺中缓解疼痛的效果,以减轻患者疼痛,提高其舒适度。方法：选择2012年1～6月在本院住院输液的患者60例,随机分为对照组和观察组各30例,观察组按实验设计方法选择好静脉,应用2％盐酸利多卡因注射液4ml浸湿纱布,湿敷拟穿刺输液点3rnin后穿刺静脉输液;对照组采用的生理盐水4ml浸湿纱布湿敷穿刺点3rain行输液作对照,观察两组患者疼痛情况。结果：两组患者疼痛程度比较有统计学意义（P〈0．05）。结论：应用2％盐酸利多卡因注射液湿敷穿刺点3min后,有缓解疼痛的作用。     

Cancer pain relief by continuous administration of epidural morphine in a hospital setting and at home.

Fifteen patients with severe pain due to malignancy were treated by continuous epidural morphine infusions. A disposable external pump was used. Patients were treated in a hospital setting or at home for a total of 906 days. Pain intensity was estimated by VAS. The pumps functioned well. Bacterial growth was found in 0.6% of the balloon reservoirs used, while the epidural filters were free from growth. There were no clinical infections. It appears that this delivery system is safe, practical and suitable for use in the home environment.     

LYS-plasminogen shortens the duration of local thrombolytic treatment of peripheral arterial occlusions--a randomized controlled trial

Local thrombolytic treatment of peripheral arterial occlusions, which has been accepted as a therapeutic alternative to surgical treatment, is not always successful. One of the reasons for unsuccessful thrombolytic treatment might be a low concentration of plasminogen in the thrombus or insufficient activation of the thrombolytic system. Therefore the purpose of this study was to determine whether the success of local treatment of peripheral arterial occlusions of lower extremities with streptokinase could be improved by enriching the thrombus with exogenous plasminogen and furthermore, if the therapeutic success depends on a systemic fibrinolytic effect. In a prospective randomized study two groups of patients with acute and subacute arterial occlusions of the lower limbs (Stage III, IV) were treated with a continuous infusion of local low dose of streptokinase (SK). The first group (45 patients, mean age 73 years) was treated with SK only (3750 IU/hour) (SK group). While the patients in the second group (43 patients, mean age 72 years) received exogenous lys-plasminogen (7.5 mg) before application of SK in thrombi (SK-Plg group). The treatment was successful in 69% (31 out of 45 patients) of the SK group and in 77% (33 out of 43 patients) of the SK-Plg group. Although lysis of thrombi was observed more frequently in the SK-Plg group than in the SK-group, the clinical outcome was comparable between groups. In successfully treated patients from the SK-Plg group the duration of treatment was significantly shorter than in the SK group (33 +/- 8 hr vs. 53 +/- 11 hr, p < 0.01). A significant decrease of fibrinogen concentration as an indicator of activation of fibrinolysis was not observed in the majority of treated patients. On the other hand, in successfully treated patients of both groups, the following was observed: 24 hour after the beginning of treatment, euglobulin clot lysis times were shortened to half of baselines values, and the plasminogen concentration was also significantly reduced (to 55% of the baseline value). In unsuccessfully treated patients no significant changes in fibrinolytic parameters were observed. The results of our study indicated that enrichment of the thrombus with exogenous plasminogen does not significantly improve the percentage of successful recanalization of peripheral arteries with a local low dose of SK, but significantly shortens the duration of treatment up to reperfusion. The study also showed that in local thrombolysis for the treatment of arterial occlusion a certain degree of systemic activation of the fibrinolytic system is essential for successful dissolution of the thrombi.     

Effects of high thoracic epidural anesthesia and local anesthetics on bronchial hyperreactivity

Bronchial hyperreactivity can cause life threatening bronchospasm after airway irritation. Therefore, endotracheal intubation is avoided in asthmatics when feasible. High thoracic epidural anesthesia can be used to avoid endotracheal intubation and offers less postoperative pulmonary complications when compared to systemic postoperative analgesia. However, there are concerns that it might also cause impaired ventilation by extended motor blockade, increased airway resistance, and increased bronchial reactivity because of pulmonary sympathicolysis. Nevertheless, high thoracic epidural anesthesia causes only a slight decrease in vital capacity and neither an increase in airway resistance nor increased bronchial reactivity. In fact, it causes a decrease in bronchial reactivity in patients with bronchial hyperreactivity mostly due to the systemic effect of the local anesthetic. The attenuation of bronchial hyperreactivity can be shown as a dose dependent effect of lidocaine and bupivacaine. The intravenous effect of lidocaine is comparable to the effect of a moderate dose of salbutamol and leads to an additive effect when both drugs are used in combination. Overall, high thoracic epidural anesthesia can be used safely in patients with bronchial hyperreactivity and intravenous administration of lidocaine (1.5–2.0 mg · kg⁻¹) can be used as a prophylactic treatment prior to airway instrumentation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effectiveness of continuous femoral nerve block for pain relief after total knee arthroplasty: comparison with epidural patient-controlled analgesia and periarticular injection

ObjectiveTo compare the clinical outcomes among three analgesic techniques, continuous femoral nerve block (CFNB), epidural patient-controlled analgesia (EPCA) and periarticular injection (PAI), in patients undergoing total knee arthroplasty (TKA).MethodsThis retrospective case–control study enrolled patients that underwent TKA. Visual analogue scale (VAS) pain scores, sleep disturbance, additional opioid consumption and incidence of opioid-related side-effects were assessed.ResultsA total of 120 patients were categorized into three groups: EPCA (group A, n = 40), PAI (group B, n = 40) and CFNB (group C, n = 40). Group C had significantly lower VAS pain scores than groups A and B at 8, 12 and 24 h after TKA. There were no significant differences in VAS pain scores among the three groups from 48 h after TKA. Sleep quality on the first day after surgery was significantly better in group C than in groups A and B. Additional opioid consumption was significantly lower in the group C than in the groups A and B. Group C showed a lower rate of opioid-related side-effects than groups A and B.ConclusionCFNB was a more effective additional analgesic technique than EPCA or PAI for acute postoperative pain control within 24 h of TKA.     

The use of local anesthetics in the treatment of chronic pain.

Local anesthetics are an important and effective tool in the treatment of patients with chronic pain syndromes. Orthopaedic nurses are in a pivotal position to assess potential problems and intervene where appropriate. This article addresses the pharmacology of local anesthesia, indications for nerve blocks with local anesthetics, and nursing management.     

Epidural opiates and local anesthetics for the management of cancer pain.

The role of epidural morphine in chronic cancer pain treatment is unresolved. In a population of 1205 cancer patients, the aggressive use of systemic opiates limited the trial of epidural analgesia to 16 cases. Successful analgesia was achieved with epidural morphine alone in 6 of these 16 cases following systemic opiate failure. The addition of bupivacaine produced analgesia in all of the 10 remaining cases and was successful chronically in 6 cases. Complications occurred in 11 of the 16 cases of epidural analgesia and included dislodged or broken catheters, pain on injection, hyperesthesia from epidural morphine and bleeding or infection related to the epidural catheter. Epidural morphine is indicated only in selected cancer pain patients and, although bupivacaine extends the efficacy of epidural analgesia, these methods are accompanied by problems and limitations.