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Background: Chronic postsurgical pain (CPSP) has been linked to many surgical settings. The authors aimed to analyze functional genetic polymorphisms and clinical factors that might identify CPSP risk after inguinal hernia repair, hysterectomy, and thoracotomy., Methods: This prospective multicenter cohort study enrolled 2,929 patients scheduled for inguinal hernia repair, hysterectomy (vaginal or abdominal), or thoracotomy. The main outcome was the incidence of CPSP confirmed by physical examination 4 months after surgery. The secondary outcome was CPSP incidences at 12 and 24 months. The authors also tested the associations between CPSP and 90 genetic markers plus a series of clinical factors and built a CPSP risk model., Results: Within a median of 4.4 months, CPSP had developed in 527 patients (18.0%), in 13.6% after hernia repair, 11.8% after vaginal hysterectomy, 25.1% after abdominal hysterectomy, and 37.6% after thoracotomy. CPSP persisted after a median of 14.6 months and 26.3 months in 6.2% and 4.1%, respectively, after hernia repair, 4.1% and 2.2% after vaginal hysterectomy, 9.9% and 6.7% after abdominal hysterectomy, and 19.1% and 13.2% after thoracotomy. No significant genetic differences between cases and controls were identified. The risk model included six clinical predictors: (1) surgical procedure, (2) age, (3) physical health (Short Form Health Survey-12), (4) mental health (Short Form Health Survey-12), (5) preoperative pain in the surgical field, and (6) preoperative pain in another area. Discrimination was moderate (c-statistic, 0.731; 95% CI, 0.705 to 0.755)., Conclusions: Until unequivocal genetic predictors of CPSP are understood, the authors encourage systematic use of clinical factors for predicting and managing CPSP risk.

Background: Chronic postsurgical pain, a significant public health problem, occurs in 10 to 50% of patients undergoing major surgery. Acute pain induces endogenous analgesia termed conditioned pain modulation (CPM), and the strength of CPM preoperatively predicts the likelihood of chronic postsurgical pain. The relation between CPM and recovery from surgery has not been examined in preclinical models., Methods: CPM was assessed in individual rats and correlated with each animal's time course of recovery of hypersensitivity after partial spinal nerve ligation. The role of descending noradrenergic pathways in the spinal cord to mechanisms of CPM and recovery was tested using idazoxan to block noradrenergic receptors or antidopamine β-hydroxylase-conjugated saporin to ablate these pathways. Behavioral hypersensitivity, static weight bearing, and spinal glial activation were measured after partial spinal nerve ligation., Results: The strength of CPM varied over two-fold between individuals and was directly correlated with the slope of recovery from hypersensitivity after surgery (P < 0.0001; r = 0.660). CPM induced the release of norepinephrine in the spinal cord and was partially blocked by intrathecal idazoxan or dopamine β-hydroxylase-saporin. Dopamine β-hydroxylase-saporin also slowed recovery and enhanced spinal glial activation after partial spinal nerve ligation surgery. Ongoing activation of these pathways was critical to sustained recovery because intrathecal dopamine β-hydroxylase-saporin given 7 weeks after recovery reinstituted hypersensitivity, while having no effect in animals without previous surgery., Conclusion: Collectively, these studies provide a clear back-translation from clinical observations of CPM and chronic postsurgical pain and suggest that the ability to engage ongoing descending endogenous noradrenergic signaling may be critical in determining time course of recovery from hypersensitivity after surgery.

Background: Anesthetics, analgesics, and surgery may profoundly affect sleep architecture and aggravate sleep-related breathing disturbances. The authors hypothesized that patients with preoperative polysomnographic evidence of obstructive sleep apnea (OSA) would experience greater changes in these parameters than patients without OSA., Methods: After obtaining approvals from the Institutional Review Boards, consented patients underwent portable polysomnography preoperatively and on postoperative nights (N) 1, 3, 5, and 7 at home or in hospital. The primary and secondary outcome measurements were polysomnographic parameters of sleep-disordered breathing and sleep architecture., Results: Of the 58 patients completed the study, 38 patients had OSA (apnea hypopnea index [AHI] >5) with median preoperative AHI of 18 events per hour and 20 non-OSA patients had median preoperative AHI of 2. AHI was increased after surgery in both OSA and non-OSA patients (P < 0.05), with peak increase on postoperative N3 (OSA vs. non-OSA, 29 [14, 57] vs. 8 [2, 18], median [25th, 75th percentile], P < 0.05). Hypopnea index accounted for 72% of the postoperative increase in AHI. The central apnea index was low (median = 0) but was significantly increased on postoperative N1 in only non-OSA patients. Sleep efficiency, rapid eye movement sleep, and slow-wave sleep were decreased on N1 in both groups, with gradual recovery., Conclusions: Postoperatively, sleep architecture was disturbed and AHI was increased in both OSA and non-OSA patients. Although the disturbances in sleep architecture were greatest on postoperative N1, breathing disturbances during sleep were greatest on postoperative N3.

Background: Interindividual variability in postoperative pain presents a clinical challenge. Preoperative quantitative sensory testing is useful but time consuming in predicting postoperative pain intensity. The current study was conducted to develop and validate a predictive model of acute postcesarean pain using a simple three-item preoperative questionnaire., Methods: A total of 200 women scheduled for elective cesarean delivery under subarachnoid anesthesia were enrolled (192 subjects analyzed). Patients were asked to rate the intensity of loudness of audio tones, their level of anxiety and anticipated pain, and analgesic need from surgery. Postoperatively, patients reported the intensity of evoked pain. Regression analysis was performed to generate a predictive model for pain from these measures. A validation cohort of 151 women was enrolled to test the reliability of the model (131 subjects analyzed)., Results: Responses from each of the three preoperative questions correlated moderately with 24-h evoked pain intensity (r = 0.24-0.33, P < 0.001). Audio tone rating added uniquely, but minimally, to the model and was not included in the predictive model. The multiple regression analysis yielded a statistically significant model (R = 0.20, P < 0.001), whereas the validation cohort showed reliably a very similar regression line (R = 0.18). In predicting the upper 20th percentile of evoked pain scores, the optimal cut point was 46.9 (z =0.24) such that sensitivity of 0.68 and specificity of 0.67 were as balanced as possible., Conclusions: This simple three-item questionnaire is useful to help predict postcesarean evoked pain intensity, and could be applied to further research and clinical application to tailor analgesic therapy to those who need it most.

Background: Several recent studies suggest that repetitive transcranial magnetic stimulation can temporarily reduce pain perception in neuropathic pain patients and in healthy adults using laboratory pain models. No studies have investigated the effects of prefrontal cortex stimulation using transcranial magnetic stimulation on postoperative pain., Methods: Twenty gastric bypass surgery patients were randomly assigned to receive 20 min of either active or sham left prefrontal repetitive transcranial magnetic stimulation immediately after surgery. Patient-controlled analgesia pump use was tracked, and patients also rated pain and mood twice per day using visual analog scales., Results: Groups were similar at baseline in terms of body mass index, age, mood ratings, pain ratings, surgery duration, time under anesthesia, and surgical anesthesia methods. Significant effects were observed for surgery type (open vs. laparoscopic) and condition (active vs. sham transcranial magnetic stimulation) on the cumulative amount of patient-delivered morphine during the 44 h after surgery. Active prefrontal repetitive transcranial magnetic stimulation was associated with a 40% reduction in total morphine use compared with sham during the 44 h after surgery. The effect seemed to be most prominent during the first 24 h after cortical stimulation delivery. No effects were observed for repetitive transcranial magnetic stimulation on mood ratings., Conclusions: A single session of postoperative prefrontal repetitive transcranial magnetic stimulation was associated with a reduction in patient-controlled analgesia pump use in gastric bypass surgery patients. This is important because the risks associated with postoperative morphine use are high, especially among obese patients who frequently have obstructive sleep apnea, right ventricular dysfunction, and pulmonary hypertension. These preliminary findings suggest a potential new noninvasive method for managing postoperative morphine use.

Acupuncture and related techniques are increasingly practiced in conventional medical settings, and the number of patients willing to use these techniques is increasing. Despite more than 30 yr of research, the exact mechanism of action and efficacy of acupuncture have not been established. Furthermore, most aspects of acupuncture have yet to be adequately tested. Therefore, considerable controversy remains about the role of acupuncture in clinical medicine. Acupuncture apparently does not reduce volatile anesthetic requirement by a clinically important amount. However, preoperative sedation seems to be a promising application of acupuncture in perioperative settings. Acupuncture may be effective for postoperative pain relief but requires a high level of expertise by the acupuncture practitioner. Acupuncture and related techniques can be used for treatment and prophylaxis of postoperative nausea and vomiting in routine clinical practice in combination with or as an alternative to conventional antiemetics when administered before induction of general anesthesia.

Background: Anterior cruciate ligament reconstruction is a complex outpatient surgical procedure often associated with pain. Traditionally, the procedure is performed under general anesthesia and often requires the use of the PACU. Refractory pain and/or nausea/vomiting occasionally leads to an unplanned hospital admission. In this study, the authors examine the associations of nerve block analgesia for these patients and its associated reductions in PACU use, hospital admission, and hospital costs., Methods: This was an observational, nonrandomized study in which existing data regarding patients' day-of-surgery outcomes were merged with hospital cost data. We reviewed a consecutive sample of 948 men and women who were in good health and underwent anterior cruciate ligament reconstruction in an outpatient surgery unit between July 1995 and June 1999., Results: The use of nerve block analgesia was associated with reduced PACU admissions to 18% and decreased unplanned hospital admission rates from 17% to 4%. Multivariate linear regression analysis showed that patients bypassing the PACU had an associated hospital cost reduction of 12% (P = 0.0001), whereas patients who needed hospital admission had an associated hospital cost increase of 11% (P = 0.0003)., Conclusions: The use of nerve blocks for acute pain management in patients undergoing anterior cruciate ligament reconstruction is associated with PACU bypass and reliable same-day discharge. Although the cost savings for this one procedure are unlikely to generate sufficient cost savings via staffing reductions, extrapolating these results to a large volume of all types of invasive outpatient orthopedic procedures may have the potential to create significant hospital cost savings.

Background: This randomized, double-blinded, placebo-controlled study investigated the efficacy of patient-controlled regional analgesia using an infraclavicular brachial plexus perineural catheter and a portable infusion pump for outpatients undergoing moderately painful, upper extremity orthopedic surgery., Methods: Preoperatively, patients (n = 30) received an infraclavicular nerve block and perineural catheter. Postoperatively, patients were discharged home with oral narcotics and a portable infusion pump delivering study solution (0.2% ropivacaine or 0.9% saline) via the catheter for 3 days. Investigators and patients were blinded to random group assignment. Daily end points included pain scores at rest and with limb movement, narcotic use and side effects, sleep quality, patient satisfaction, and symptoms of catheter- or local anesthetic-related complications., Results: Ropivacaine (n = 15) infusion significantly reduced pain compared with saline (n = 15) infusion (P < 0.001). For example, the average pain with movement (scale, 0-10) on postoperative day 1 was 6.1 +/- 2.3 for the saline group versus 2.5 +/- 1.6 for the ropivacaine group (P < 0.001). Oral narcotic use and related side effects were significantly decreased in the ropivacaine group. For example, on postoperative day 1, mean tablet consumption was 5.5 +/- 2.4 and 1.7 +/- 1.6 for the saline and ropivacaine groups, respectively (P < 0.001). Sleep disturbance scores were 10-fold greater for saline administration than for ropivacaine infusion (P < 0.001). Overall satisfaction was significantly greater in the ropivacaine group. No catheter- or local anesthetic-related complications occurred., Conclusion: After moderately painful orthopedic surgery of the upper extremity, ropivacaine infusion using a portable, mechanical pump and an infraclavicular brachial plexus perineural catheter at home decreased pain, sleep disturbances, narcotic use and related side effects, and improved overall satisfaction.

Background: Transcutaneous electrical nerve stimulation (TENS) at either an acupoint or dermatome corresponding to the surgical incision produces comparable decreases in postoperative opioid requirements and opioid-related side effects. However, the effect of the frequency of the electrical stimulus on the postoperative analgesic response to TENS therapy has not been studied., Methods: One hundred women undergoing major gynecological procedures with a standardized general anesthetic technique were enrolled in the study. Patients were randomly assigned to four groups: group I, patient-controlled analgesia (PCA) plus sham TENS (no stimulation); group II, PCA plus low-frequency (2-Hz) TENS; group m, PCA plus high-frequency (100-Hz) TENS; group IV, PCA plus mixed-frequency (2- and 100-Hz) TENS. The PCA device was programmed to deliver 2-3 mg intravenous boluses of morphine with a lockout interval of 10 min. The TENS device was used every 2 h during the day. Standard 100-mm visual analog scales were used to assess pain, sedation, fatigue, and nausea at specific intervals after surgery., Results: Mixed frequency (2 and 100 Hz) of stimulation decreased morphine requirements by 53% compared with the sham group; low (2-Hz) and high (100-Hz) frequencies produced 32% and 35% decreases, respectively. All three "active" TENS groups reduced the duration of PCA therapy, as well as the incidence of nausea, dizziness, and itching., Conclusions: TENS decreased postoperative opioid analgesic requirements and opioid-related side effects when utilized as an adjunct to PCA after lower abdominal surgery. Use of TENS at mixed (2- and 100-Hz) frequencies of stimulation produced a slightly greater opioid-sparing effect than either low (2-Hz) or high (100 Hz) frequencies alone.

Background: Continuous passive motion after major knee surgery optimizes the functional prognosis but causes severe pain. The authors tested the hypothesis that postoperative analgesic techniques influence surgical outcome and the duration of convalescence., Methods: Before standardized general anesthesia, 56 adult scheduled for major knee surgery were randomly assigned to one of three groups, each to receive a different postoperative analgesic technique for 72 h: continuous epidural infusion, continuous femoral block, or intravenous patient-controlled morphine (dose, 1 mg; lockout interval, 7 min; maximum dose, 30 mg/4 h). The first two techniques were performed using a solution of 1% lidocaine, 0.03 mg/ml morphine, and 2 microg/ml clonidine administered at 0.1 ml x kg(-1) x h(-1). Pain was assessed at rest and during continuous passive motion using a visual analog scale. The early postoperative maximal amplitude of knee flexion was measured during continuous passive motion at 24 h and 48 h and compared with the target levels prescribed by the surgeon. To evaluate functional outcome, the maximal amplitudes were measured again on postoperative day 5, at hospital discharge (day 7), and at 1- and 3-month follow-up examinations. When the patients left the surgical ward, they were admitted to a rehabilitation center, where their length of stay depended on prospectively determined discharge criteria, Results: The continuous epidural infusion and continuous femoral block groups showed significantly lower visual analog scale scores at rest and during continuous passive motion compared with the patient-controlled morphine group. The early postoperative knee mobilization levels in both continuous epidural infusion and continuous femoral block groups were significantly closer to the target levels prescribed by the surgeon than in the patient-controlled morphine group. On postoperative day 7, these values were 90 degrees (60-100 degrees)(median and 25th-75th percentiles) in the continuous epidural infusion group, 90 degrees (60-100 degrees) in the continuous femoral block group, and 80 degrees (60-100 degrees) in the patient-controlled morphine group (P < 0.05). The durations of stay in the rehabilitation center were significantly shorter: 37 days (range, 30-45 days) in the continuous epidural infusion group, 40 days (range, 31-60 days) in the continuous femoral block group, and 50 days (range, 30-80 days) in the patient-controlled morphine group (P < 0.05). Side effects were encountered more frequently in the continuous epidural infusion group., Conclusion: Regional analgesic techniques improve early rehabilitation after major knee surgery by effectively controlling pain during continuous passive motion, thereby hastening convalescence.

Background: The efficacy and safety of patient-controlled epidural analgesia (PCEA) for postoperative analgesia on hospital wards was studied., Methods: Postoperative analgesia was provided for 1,030 patients with PCEA using 0.05% bupivacaine and fentanyl, 4 microg/ml, in a standardized manner. Patients were seen at least twice a day by the staff of the anesthesia pain management service. Prospectively gathered data included verbal pain scores at rest and activity (0-10); consumption of bupivacaine and fentanyl; and incidences of pruritus, nausea, sedation, hypotension, motor block, and respiratory depression. Descriptive statistics were used. Risk factors for side effects were determined using logistic regression., Results: The study included 552 women and 477 men who underwent a median (mode) of 3 (2) days of PCEA. Their mean age was 59 +/- 16 yr and their mean weight was 76 +/- 19 kg. There were 454 abdominal, 165 gynecologic, 126 urologic, 108 vascular, 90 thoracic, 83 orthopedic, and 4 plastic surgical procedures. Median (mode) pain scores were 1 (0) at rest and 4 (5) with activity on postoperative day 1. Incidences of side effects were 16.7% (pruritus), 14.8% (nausea), 13.2% (sedation), 6.8% (hypotension), 2% (motor block), and 0.3% (respiratory depression). Reasons for termination of PCEA were elective (82%), displaced epidural catheter (12%), anticoagulation (3%), infection (1%), side effects (1%), inadequate analgesia (1%), and other (<1%). Risk factors for side effects were female sex, patient weight <73 kg, patient age <58 yr, bupivacaine and fentanyl consumption >9 ml/h, use of analgesic adjuncts, and lumbar placement of epidural catheters., Conclusion: Patient-controlled epidural analgesia provides effective and safe postoperative analgesia on hospital wards.

Background: Intraoperative hypothermia is common and persists for several hours after surgery. Hypothermia may prolong immediate recovery by augmenting anesthetic potency, delaying drug metabolism, producing hemodynamic instability, or depressing cognitive function. Accordingly, the authors tested the hypothesis that intraoperative hypothermia prolongs postoperative recovery., Methods: Patients undergoing elective major abdominal surgery (n = 150) were anesthetized with isoflurane, nitrous oxide, and fentanyl. They were randomly assigned to routine thermal management (hypothermia) or extra warming (normothermia). Postoperative surgical pain was treated with patient-controlled analgesia. Fitness for discharge from the postanesthesia care unit was evaluated at 20-min intervals by investigators blinded to group assignment and postoperative core temperatures. Scoring was based on a modification of a previously published system that included activity, ventilation, consciousness, and hemodynamic responses. Patients were considered fit for discharge when they sustained a score of 80% (13 points) for at least two consecutive measurement periods., Results: Morphometric characteristics and anesthetic management were similar in each group. Final intraoperative core temperatures differed by approximately 2 degrees C: 34.8 +/- 0.6 versus 36.7 +/- 0.6 degrees C (mean +/- SD, P < 0.001). Postoperative pain scores and postoperative use of patient-controlled opioid were similar. Hypothermic patients required approximately 40 min longer (94 +/- 65 vs. 53 +/- 36 min) to reach fitness for discharge, even when return to normothermia was not a criterion (P < 0.001). Duration of recovery in the two groups differed by approximately 90 min when a core temperature >36 degrees C was also required (P < 0.001)., Conclusion: Maintaining core normothermia decreases the duration of postanesthetic recovery and may, therefore, reduce costs of care.

Background: Although experimental evidence indicates that preemptive intrathecal treatment with local anesthetics reduces postinjury neuronal hyperexcitability, clinical evidence indicates that preemptive treatments do not consistently reduce postoperative pain. The current study used experimental models of postinjury nociception, in which rats received subcutaneous or intraarticular injections of the irritant formalin, to evaluate the effects of peripheral inflammation, or the use of agents supplemental to anesthesia, as possible confounding influences on the effectiveness of preinjury and postinjury intrathecal local anesthetic treatments., Methods: In experiment 1, lumbar intrathecal lidocaine (30 microliters, 2%), given either 5 min before or 5 min after hind paw injection of 50 microliters of varying concentrations of formalin, was compared with intrathecal cerebrospinal fluid, for their effects on nociceptive responses in the late phase of the formalin test. Furthermore, the effect of hind paw injection of 50 microliters of 2.5, 3.75, or 5.0% formalin on peripheral inflammation was assessed by measuring plasma extravasation in the hind paws of rats given Evans Blue dye (50 mg/kg, intravenous). In experiment 2, rats received a deep tissue injury (100 microliters of 5.0% formalin into the knee joint) while under halothane anesthesia. In addition to halothane (3-4%), rats received either saline, pentobarbital (13 mg/kg, intraperitoneal), or pentobarbital + morphine (0.5 mg/kg, intravenous), with or without preinjury or postinjury spinal anesthesia using intrathecal bupivacaine (30 microliters, 0.75%), to assess the effects of supplemental treatments on the preemptive effects of intrathecal bupivacaine., Results: Lumbar intrathecal lidocaine pretreatment, but not posttreatment, significantly reduced late phase nociceptive responses to hind paw injections of 2.5% formalin. The preemptive effects of lidocaine were overridden in rats that received hind paw injections of 3.75 and 5.0% formalin. Hind paw injection of 50 microliters of 3.75 or 5.0%, but not 2.5% formalin produced an increase in plasma extravasation. Either pentobarbital or pentobarbital + morphine treatment, or a pentobarbital + morphine treatment and postinjury treatment with intrathecal bupivacaine failed to produce a significant reduction in the nociceptive response to the deep tissue injury. However, rats that received pentobarbital + morphine treatments and intrathecal bupivacaine before the injury had significantly reduced nociceptive responses to deep tissue injury when compared to the saline control group, but not to the group that received pentobarbital + morphine treatment and postinjury treatment with bupivacaine., Conclusions: The current results attest to the important effects of ongoing inputs from inflamed tissue, and the use of supplemental treatments, as important confounding factors that may influence the effectiveness of preemptive spinal anesthesia for postoperative pain.

Background: The benefit of laparoscopy to patients has been clearly established in adults undergoing cholecystectomy. Results are less clear for appendectomy. The current study was undertaken to compare the respective 3-day postoperative periods after laparoscopic and open appendectomy in children., Methods: Sixty-three children (aged 8-15 yr) scheduled for appendectomy were randomly assigned to two groups: open and laparoscopic. Postoperative evaluation included delay of postoperative recovery (walking and feeding), pain assessment by visual analog scale during the 3 subsequent days, amount of nalbuphine administered via a patient-controlled analgesia system during the first 48 h and responses by children, parents, and nurses on the overall quality of analgesia., Results: There was no difference between groups for demographic data (particularly macroscopic aspect of appendix) analgesia, sedation, delay before eating and walking, incidence of urinary retention, nausea, vomiting. Operative time was long (P < or = to 0.05) in the laparoscopic group (54 +/- 17 min) than in the open group (39 +/- 18 min). Thirty five percent of the children had pain at the shoulder in the LAP group versus ten percent in the open group (P < or = 0.05)., Conclusions: Laparoscopy did not improve analgesia and postoperative recovery after appendectomy in children.

Background: The objective of the survey was to assess the status of acute pain management in U.S. hospitals and attitudes of adults in the U.S. toward postoperative pain management, information that has not been previously available., Methods: Two telephone questionnaire surveys were conducted U.S. hospital participants, including 100 teaching hospitals (acute care hospitals with a residency program and/or university affiliation), 100 nonteaching (community) hospitals with fewer than 200 beds, and 100 nonteaching (community) hospitals with 200 beds or more were interviewed regarding current and future pain management programs and related topics. Adult participants in 500 U.S. households were interviewed on attitudes and experiences with postoperative pain and its management., Results: Forty-two percent of the hospitals have acute pain management programs, and an additional 13% have plans to establish an acute pain management program. Seventy-seven percent of adults believe that it is necessary to experience some pain after surgery. Fifty-seven percent of those who had surgery cited concern about pain after surgery as their primary fear experienced before surgery. Seventy-seven percent of adults reported pain after surgery, with 80% of these experiencing moderate to extreme pain., Conclusions: Despite a growing trend in pain management, increased professional and public awareness including the establishment of pain management programs and public and patient education is needed to reduce the incidence and severity of postoperative pain.

Background: Continuation of intrathecal anesthesia into the postoperative period has been limited by important safety concerns. Principal among these has been the assumption that extended intrathecal therapy leads to spinal (epidural and intrathecal) space infections. To address the role of extended intrathecal catheter therapy as a cause of infections, we cultured all intrathecal catheters used to provide postoperative analgesia., Methods: All intrathecal catheters were inserted in the operating room using sterile technique. The catheters were used either for the duration of the patients stay in the intensive care unit or until they were no longer judged to provide a therapeutic advantage. They were removed without skin preparation. The distal 2-3 cm of the catheters was cultured using semiquantitative culture methods. Results were divided into four groups: group 1, negative culture results; group 2, ten or fewer colonies of growth; group 3, more than 10 colonies on initial plates and/or growth from broth cultures; and group 4, any bacterial growth, along with evidence of local or central nervous system infections., Results: Cultures were obtained from 139 patients with a mean indwelling catheter time of 66.1 h. Group 1 (102 patients) had a mean indwelling duration of 55 h. Group 2 (26 patients) and group 3 (11 patients) had significantly longer indwelling duration (83.2 h P = .0023, 129.6 h P = < .0001, respectively) than group 1. Cultures of cerebrospinal fluid obtained simultaneously with catheter cultures in 9 cases (5 in group 2 and 4 in group 3) showed no growth. No patient had evidence of local or central nervous system infection. Difficulty of catheter placement (number of attempts made and the number of levels explored), antibiotic administration, the composition of the postoperative infusions and the number of catheter breaks in the postoperative period were similar in each group. With the exception of two catheters in group 3, (cultured at 49 and 54 h), significant bacterial growth (more than ten colonies) was observed only after more than 96 h of indwelling duration., Conclusions: Application of semiquantitative culture methods assisted in explaining the results seen in group 2 as secondary to contamination of the catheter that occurred on removal. Higher numbers of bacteria (group 3) may define a population at increased risk for infectious complications. The results of this study do not absolutely resolve the issue of infectious risk associated with postoperative intrathecal catheter use, nor do they define a safe period beyond which the risk of continued catheter use would be unacceptable. However, it appears that limited periods of use (96 h or less) is not associated with either frequent local or spinal infections. Semiquantitative culture methods may help identify individuals (with catheter cultures yielding more than ten colonies) at increased risk for infectious complications and in need of closer observation.

The authors conducted a randomized double-blind controlled study comparing groups of patients receiving iv or epidural fentanyl infusions to determine whether, at comparable levels of analgesia, 1) the severity of side effects was different; and 2) plasma fentanyl concentrations differed between the two groups. Twenty-eight ASA physical status 2 women scheduled to undergo elective cesarean section were randomized into two groups to either receive fentanyl intravenously and saline epidurally or fentanyl epidurally and saline intravenously. After delivery of the infants under epidural anesthesia, each patient received a bolus of fentanyl 1.5 microgram/kg either intravenously or epidurally, and a fentanyl infusion was begun via the same route. Concurrently, a saline bolus and infusion were given via the alternate route. The rates of the fentanyl and saline infusions were adjusted until each patient was comfortable. Patients rated their pain, nausea, and pruritus on visual analogue scales. Sedation was evaluated by an observer. Respiratory depression was evaluated by end-tidal PCO2. Data were analyzed by unpaired two-tail t tests. Plasma fentanyl concentrations were measured at 12 and 24 h. Three patients in the iv group were dropped from the study because of inadequate pain relief. For the remaining 25 patients, similar infusion rates of fentanyl were required to produce similar levels of analgesia at 12 and 24 h. The severity of nausea, pruritus and sedation, and end-tidal PCO2 were similar for both groups. The plasma concentrations of fentanyl were significantly greater in those who received iv fentanyl at 12 h but not at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

This study compared the postoperative pain relief provided by simple instillation of bupivacaine into a hernia wound with that provided by ilioinguinal/iliohypogastric (IG/IH) nerve block. Sixty children undergoing inguinal hernia repair under general anesthesia were randomized to receive 0.25 ml/kg of 0.25% bupivacaine for either IG/IH nerve block or up to 0.5 ml/kg of the same solution for instillation nerve blocks. In the postanesthesia care unit (PACU), a trained blinded observer evaluated the patient's level of postoperative pain using a standardized 10-point objective pain scale. Fentanyl 1-2 micrograms/kg was administered intravenously to any child scoring 6 or more points on the pain scale. The difference in pain scores among the two groups were compared. The two groups were not significantly different in age, duration of surgery, or anesthesia. There was no significant difference between patients who received the two treatment modalities in their pain scores, analgesic requirements in the PACU, recovery times, and discharge times. These results demonstrate that the simple instillation of local anesthetics into a wound provides postoperative pain relief following hernia repair, which is as effective as that provided by intraoperative IG/IH nerve block.

The authors studied the effects of epidural sufentanil (0.75 microgram.kg-1) after urologic surgery in 15 children ranging in age from 4 to 12 yr, and in weight from 14 to 47 kg. The onset and duration of analgesia were 3.0 +/- 0.3 and 198 +/- 19 min, respectively (mean +/- SEM). Side effects included pruritus (3/15), nausea and vomiting (5/15), drowsiness (10/15), and urinary retention (1/11). No apnea was observed. Periosteal analgesia and ventilation were studied in eight of the children (mean age 8.6 +/- 0.8 yr). There was significant periosteal analgesia of the tibia (30, 60, 90, and 120 min after injection) and of the radius (60, 90, and 120 min after injection). Resting respiratory rate and tidal volume did not change during the study. Resting minute-ventilation decreased from 6.3 +/- 0.5 l.min-1 preoperatively to 5.6 +/- 0.6 l.min-1 (P less than 0.05) postoperatively, before epidural sufentanil injection; it did not decrease further after epidural sufentanil. Similarly, end-tidal CO2 tension increased significantly from 37.2 +/- 0.7 mmHg preoperatively to 39.9 +/- 1.2 mmHg (P less than 0.05) postoperatively, before epidural sufentanil; epidural sufentanil did not cause a further significant increase in end-tidal CO2 tension. The slope of the CO2 ventilatory response curve decreased significantly from 1.68 +/- 0.12 l.min-1. mmHg-1 preoperatively to 1.10 +/- 0.13 l.min-1.mmHg-1 (P less than 0.01) postoperatively. There were further significant decreases to 0.68 +/- 0.10 and 0.89 +/- 0.16 l.min-1.mmHg-1 30 and 60 min after epidural sufentanil.(ABSTRACT TRUNCATED AT 250 WORDS)