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Study Objective: To determine the optimum time of administration of diclofenac in patients undergoing ambulatory knee arthroscopy: either preoperatively or postoperatively. Design: Randomized, double-blind study. Setting: Ambulatory surgical unit in a tertiary referral hospital. Patients: 127 ASA physical status I and II patients undergoing ambulatory knee arthroscopy. Interventions: Patients were randomized into three groups. The Preop group received 50 mg of potassium diclofenac orally 1 hour preoperatively and a placebo 30 minutes postoperatively. The Pre+postop group received 25 mg of potassium diclofenac 1 hour preoperatively and 25 mg diclofenac 30 minutes postoperatively. The Postop group received a placebo 1 hour before surgery and 50 mg of potassium diclofenac 30 minutes postoperatively. Measurements and Main Results: The Postop group received a placebo 1 hour preoperatively and 50 mg of potassium diclofenac 30 min postoperatively. Postoperatively, patients used intravenous patient-controlled analgesia (PCA) with fentanyl. Total fentanyl consumption was recorded. During the recovery period, pain was assessed using a visual analog scale (VAS) at 30-minute intervals. Pain was assessed in both legs at rest, on flexion, and extension of the knee. There were no significant differences in pain scores either at rest or on movement of the operative knee among the Preop, Pre+postop, and Postop groups. The consumption of fentanyl via PCA showed no significant differences among the groups. Conclusions: There is no difference in pain relief whether diclofenac is given preoperatively or postoperatively in patients undergoing unilateral ambulatory knee arthroscopy. Preoperative and postoperative treatment with diclofenac potassium is equally effective.

Summary A number of reports have been published describing (recurrent) respiratory depression after the use of alfentanil intraoperatively. To evaluate the severity of respiratory depression after the administration of alfentanil, 49 patients undergoing general anaesthesia for abdominal hysterectomy were randomly allocated to one of three groups and studied in a double-blind manner. During surgery patients received no opioids (group 1), low dose (group 2) or high dose of alfentanil (group 3). Postoperatively patients were monitored with pulse oximetry and respiratory inductive plethysmography. Postoperative pain was managed with PCA morphine. Thirty-nine patients completed the study. Respiratory depressant effects were found in all three groups. A higher number of apnoeas (at 60 minutes in group 1: 3.3 ± 1.6; group 2: 3.5 ± 1.8; group 3: 12.2 ± 2.8) and a higher morphine consumption was found in group 2 when compared with group 1 and 3. No differences were found among the groups in the other respiratory parameters or in terms of the number of patients with respiratory depression at any one time. No cases of clear-cut recurrent respiratory depression were identified.

Background Fast-track cardiac anesthesia, using low-dose narcotics combined with short-acting anesthetic and sedative agents, facilitates early tracheal extubation after cardiac surgery. The incidence of awareness with this anesthetic technique has not been investigated previously. The purpose of this study was to prospectively investigate the incidence of intraoperative awareness with explicit memory of events during fast-track cardiac anesthesia. Methods Data were collected prospectively over a 4-month period from 617 consecutive adult patients undergoing cardiac surgery at a university hospital. All patients received a fast-track cardiac anesthetic regimen. Patients underwent a structured interview by a research nurse 18 h after extubation. A standard set of questions was asked during this interview to determine if the patient had explicit memory of any event from induction of anesthesia to recovery of consciousness. Results Nine patients did not complete a postoperative interview because of death (n = 7) or postoperative confusion (n = 2). The last memory before surgery reported in 420 (69.1%) patients was waiting in the holding area at the operating suite, and in the remaining 188 (30.9%) patients it was lying on the operating table before induction of anesthesia. Two patients (0.3%) had explicit memory of intraoperative events. One of the two patients also had explicit memory of pain. Neither patient reported adverse psychological sequelae. Conclusions The authors report an incidence of awareness in fast-track cardiac anesthesia of 0.3%. This is the lowest incidence of awareness currently reported during cardiac surgery. This low incidence of awareness may be related to the use of a balanced anesthetic technique involving the continuous administration of volatile (isoflurane) or intravenous (propofol) anesthetic agents before, during, and after cardiopulmonary bypass.

Background The efficacy and effects of epidural analgesia compared with patient-controlled analgesia (PCA) have not been reported in patients undergoing major vascular surgery. We compared the effects of epidural bupivacaine-morphine with those of intravenous PCA morphine after elective infrarenal aortic surgery. Methods Forty patients classified as American Society of Anesthesiologists physical status 2 or 3 received general anesthesia plus postoperative PCA using morphine sulfate (group PCA; n = 21) or general anesthesia plus perioperative epidural morphine-bupivacaine (group EPI; n = 19) during a period of 48 h. During operation, EPI patients received 0.05 mg/kg epidural morphine and 5 ml 0.25% bupivacaine followed by an infusion of 0.125% bupivacaine with 0.1% morphine (0.1 mg/ ml); group PCA received 0.1 mg/kg intravenous morphine sulfate. Continuous electrocardiographic monitoring (V4 and V5 leads) was performed from the night before surgery until 48 h afterward. Respiratory inductive plethysmographic data were recorded after tracheal extubation. Visual analog pain scores at rest and after movement were performed every 4 h after extubation. Results Nurse-administered intravenous morphine and time to tracheal extubation were less in group EPI, as were visual analog pain scores at rest and after movement from 20 to 48 h. Complications and the duration of intensive care unit and hospital stay were comparable. There was a similar, low incidence of postoperative apneas, slow respiratory rates, desaturation, and S-T segment depression. Conclusions Epidural morphine-bupivacaine is associated with reduced early postoperative intravenous opioid requirements, more rapid tracheal extubation, and superior analgesia after abdominal aortic surgery, with comparable respiratory effects.

The development of the passive transdermal therapeutic system (TTS) as an effective method of drug delivery has allowed the potent, lipid soluble opioid fentanyl to be administered transdermally as an analgesic agent to patients with postoperative and chronic pain.

To compare the effects of two premedication regimens on cardiorespiratory vanables, sedation, and anxiety in patients scheduled for coronary artery bypass graft (CABG) surgery. This was a prospective randomized, double-blind clinical trial. Sixty-eight patients were monitored for 1.5 hr before and 2.0 hr after premedication with lorazepam (0.03 mg·kg−1 sl). morphine (0.15 mg·kg−1im), and perphenazine (0.05 mg·kg im) [Group 1]. or with lorazepam (0.03 mg-kg−1sl) and saline (1.5 ml im) [Group 2]. All were continuously monitored with a 12-lead ECG ST monitors, respiratory inductive plethysmography (RIP). digital pulse oximetry, intra-arterial blood pressure, and artenal blood gas analysis. Sedation and anxiety scores were also recorded. The incidence and duration of myocardial ischaemia was low and similar in Groups 1 and 2. Patients in Group 1, but not m Group 2, had a greater number of events (P < 0.04) and duration (P < 0.02) of O2 desaturation; higher PaCO2 (P < 0.001), and more haemodynamic events (P < 0.006) after premedication when compared with baseline. There was no difference in RIP or ECG vanables between the two groups. Following premedication. both groups reported reduced anxiety scores and elevated sedation scores (P < 0.01), with sedation greater in Group 1 than in Group 2 (P < 0.0l). In CABG patients, premedication with lorazepam provides adequate anxiolysis and sedation, and the addition of morphine and perphenazine results in elevated PaCO2, artenal haemoglobin desaturation, and potentially adverse haemodynamic changes.

Background Economics has caused the trend of early tracheal extubation after cardiac surgery, yet no prospective randomized study has directly validated that early tracheal extubation anesthetic management decreases costs when compared with late extubation after cardiac surgery. Methods This prospective, randomized, controlled clinical trial was designed to evaluate the cost savings of early (1-6 h) versus late tracheal extubation (12-22 h) in patients after coronary artery bypass graft (CABG) surgery. The total cost for the services provided for each patient was determined for both the early and late groups from hospital admission to discharge home. All costs applicable to each of the services were classified into direct variables, direct fixed costs, and overhead (an indirect cost). Physician fees and heart catheterization costs were included. The total service cost was the sum of unit workload and overhead costs. Results One hundred patients having elective CABG who were younger than 75 yr were studied. Including all complications, early extubation (n = 50) significantly reduced cardiovascular intensive care unit (CVICU) costs by 53% (P < 0.026) and the total CABG surgery cost by 25% (P < 0.019) when compared with late extubation (n = 50). Forty-one patients (82%) in each group were tracheally extubated within the defined period. In the early extubation group, the actual departmental cost savings in CVICU nursing and supplies was 23% (P < 0.005), in ward nursing and supplies was 11% (P < 0.05), and in respiratory therapy was 12% (P < 0.05). The total cost savings per patient having CABG was 9% (P < 0.001). Further cost savings using discharge criteria were 51% for CVICU nursing and supplies (P < 0.001), 9% for ward nursing and supplies (P < 0.05), and 29% for respiratory therapy (P < 0.001), for a total cost savings per patient of 13% (P < 0.001). Early extubation also reduced elective case cancellations (P < 0.002) without any increase in the number of postoperative complications and readmissions. Conclusions Early tracheal extubation anesthetic management reduces total costs per CABG surgery by 25%, predominantly in nursing and in CVICU costs. Early extubation reduces CVICU and hospital length of stay but does not increase the rate or costs of complications when compared with patients in the late extubation group. It shifts the high CVICU costs to the lower ward costs. Early extubation also improves resource use after cardiac surgery when compared with late extubation.

This study tested the hypothesis that high dose systemic alfentanil administered before and during abdominal hysterectomy would pre-empt post-operative pain to a greater extent than administration of either low dose alfentanil or no alfentanil perioperatively. Patients (ASA 1 or 2) were randomly assigned to group 1 (n = 15), no opioid; group 2 (n = 15), low dose alfentanil; or group 3 (n = 15), high dose alfentanil. Anaesthesia was induced in group 1 with midazolam and thiopentone and was maintained with isoflurane and 70% N2O in O2. Anaesthesia was induced in group 2 with midazolam, thiopentone and i.v. alfentanil (30 microg kg(-1)), and was maintained with isoflurane, 70% N2O in O2, and bolus doses of i.v. alfentanil (10-20 microg kg(-1)) every hour. Anaesthesia was induced in group 3 with midazolam and i.v. alfentanil (100 microg kg(-1)), and was maintained with 70% N2O in O2, and an infusion of i.v. alfentanil (1-2 microg kg(-1) min(-1)). Blood samples were drawn at 30 and 120 min after surgery and assayed for plasma alfentanil. Morphine consumption and VAS pain scores were consistently lowest in group 3 over the 48 h study period. A composite measure of pain and morphine consumption was significantly lower in group 3 than group 2 up to 6 h after surgery, and significantly lower than group 1 up to 12 h. No adverse effects were observed. A 6-month follow-up did not reveal any significant differences among the three groups. It is concluded that intra-operative high dose alfentanil anaesthetic pre-empts post-operative pain after abdominal hysterectomy, but the effects are small and of short duration. Surgical procedures carried out under general anaesthesia using standard (and even high) doses of opioids intraoperatively provide suboptimal protection from the injury barrage brought about by incision and subsequent noxious surgical events.

Increasing numbers of people use cocaine recreationally and may require anesthesia care, having recently abused the drug. However, no data currently exist concerning potential interactions between toxic levels of cocaine and volatile anesthetic agents. This study investigated the effects of cocaine infusion on systemic hemodynamics, myocardial metabolism, and regional organ blood flow in relation to depth of isoflurane anesthesia.Prospective, randomized, controlled trial.A laboratory at a university medical center.Twelve miniature pigs.An open-chest swine model was used. Isoflurane (ISO) was the sole anesthetic, administered at 0.75 and 1.5 minimum alveolar concentration (MAC), and cocaine was infused (n = 6) at a rate of 0.5 mg/kg/min. Control animals (n = 6) received an equivalent amount of normal saline.Systemic and pulmonary arterial pressures and thermodilution cardiac output data were collected at 0.75 MAC and 1.5 MAC ISC. Regional myocardial and blood flows to other organs were measured using radiolabeled microspheres. Arrhythmias and altered ventricular conduction were noted only in the cocaine group, along with significant elevations in diastolic arterial pressure, coronary perfusion pressure, and systemic vascular resistance. Increased subendocardial blood flow occurred during cocaine infusion (p = 0.03); subepicardial perfusion was unchanged. Cerebral (p0.01) and spinal cord (p0.05) blood flows were reduced in animals receiving cocaine. Other organ blood flows were unchanged with depth of anesthesia or cocaine administration, with the exception of splenic blood flow (p0.04).Moderately toxic cocaine levels occurring during isoflurane at 0.75 MAC and 1.5 MAC are associated with hemodynamic abnormalities, a marked increase in systemic vascular resistance, and a tendency to produce cardiac arrhythmias. A reversal of endo/epicardial myocardial perfusion ratio occurs associated with cocaine infusion during ISO anesthesia. This is probably not related to a primary redistribution of subendocardial blood flow and may be related to a combination of increased myocardial oxygen demand and epicardial coronary vasoconstriction. The reductions in cerebral and spinal cord perfusion observed may explain, in part, the neurologic sequelae of cocaine toxicity.

Introduction: We undertook a prospective, randomized, controlled clinical trial to evaluate morbidity outcomes and safety of a modified anesthetic technique to provide shorter sedation and early extubation (1 to 6 hours) than those of the conventional anesthetic protocol used for prolonged sedation and extubation (12 to 22 hours) in patients after coronary artery bypass grafting. Methods: One hundred twenty patients undergoing elective coronary artery bypass grafting were prospectively assigned randomly to either an early extubation group ( n = 60; 15 μg·kg -1 fentanyl and 2 to 6 mg · kg -1 · hour -1 propofol and isoflurane) or to a conventional extubation group ( n = 60; 50 μg·kg -1 fentanyl and 0.1 mg·kg -1 midazolam and isoflurane). Cardiac morbidity (postoperative myocardial ischemia, postoperative myocardial infarction, and perioperative sympathoadrenal stress response), respiratory morbidity (postextubation apnea, alveolar-arterial oxygen gradient, pulmonary shunting, oxygen consumption, atelectasis, and reintubation), hemodynamic values and vasoactive medication requirements, intraoperative awareness, postoperative cognitive function, 30 day mortality, and intensive care unit and hospital lengths of stay were compared between the two groups. Results: Fifty-one of the 60 patients in each group (85%) were extubated within the defined time period. Postoperative extubation time and intensive care unit and hospital lengths of stay were significantly shorter in the early group. At 48 hours after operation, there were no significant differences between the two groups in myocardial ischemia incidences, ischemia burdens, or creatine kinase isoenzyme MB levels. Four patients in the conventional group, but not in the early group, had postoperative myocardial infarction. The extubation anesthetics used were effective in suppressing the perioperative plasma catecholamine stress response in both groups. Postextubation apnea characteristics were similar between the groups. Intrapulmonary shunt fraction improved significantly in the early group at 4 hours after extubation. The incidences and degree of atelectasis did not differ significantly between the two groups. The incidences of treated postoperative complications were comparable between the two groups, but three patients in the conventional group died as a result of stroke or postoperative myocardial infarction. Conclusion: Early extubation after coronary artery bypass grafting is safe and does not increase perioperative morbidity. There is an improvement in postextubation intrapulmonary shunt fraction and a reduction in intensive care unit and hospital lengths of stay. (J THORAC CARDIOVASC SURG 1996;112:755-64)

Ropivacaine is a new long-acting, injectable local anaesthetic currently undergoing clinical investigation world wide. It is structurally very similar to bupivacaine, but with less potential for central nervous system or cardiac toxicity. The purpose of this double-blind study was: to investigate the dose-response relationship of increasing doses of ropivacaine on the quality of anaesthesia and the duration of both motor and sensory blockade, and to compare these results with an established local anaesthetic, bupivacaine.One hundred and twenty five patients were randomly assigned to one of four treatment groups and 116 completed the study. Epidural anaesthesia was established using 25 ml test solution, injected over three minutes following a satisfactory test dose. Sensory onset, spread and duration, using the pin prick method, and motor scores using a modified Bromage scoring system were compared.A dose/response relationship was observed with increasing doses of ropivacaine for all variables tested except analgesia and muscle relaxation (P0.01). There were differences in: (i) motor onset (Levels 1 and 2), when ropivacaine 1.0% was compared with ropivacaine 0.75% and 0.5% (P0.05); (ii) in sensory duration at all levels except T6 when ropivacaine was compared with ropivacaine 0.5% (P0.05); (iii) differences in sensory duration at T12 and S1 when ropivacaine 1.0% was compared with bupivacaine 0.5% (P0.05); (iv) differences in motor duration at all levels when ropivacaine 1.0% was compared with ropivacaine 0.5% (P0.05). No serious adverse events were reported in this study.Increasing doses of ropivacaine were associated with an increased clinical effect. The most consistent differences occurred when ropivacaine 1.0% was compared with 0.5% and the least consistent between ropivacaine 0.5%, 0.75% and bupivacaine 0.5%. The main difference between ropivacaine 1.0% and bupivacaine was in sensory duration. No serious adverse events were reported.

Summary Anaesthesia for thoracic surgery involves a diversity of skills and expertise, including clinical judgement, pre-operative assessment, airway management, intra-operative physiology and pharmacology, and the challenges of prevention and therapy of post-operative pain. It is a growth area in anaesthetic research and practice, and is one of the most challenging types of clinical anaesthetic practice.

Long-term pain is a common sequela of thoracotomy, occurring in approximately 50% of patients 2 years after thoracic surgery. Despite this alarming statistic, little is known about the factors responsible for the transition of acute to chronic pain. The aim of the present study is to identify predictors of long-term post-thoracotomy pain.Follow-up was for 1.5 years for patients who had participated in a prospective, randomized, controlled trial of preemptive, multimodal analgesia.Subjects were recruited from a tertiary care center.Thirty patients who had undergone lateral thoracotomy were followed up by telephone, administered a structured interview, and classified according to long-term pain status.Present pain status was measured by a verbal rating scale (VAS). Measures obtained within the first 48 h after surgery were compared between patients with and without pain 1.5 years later. These include VAS pain scores at rest and after movement, McGill Pain Questionnaire data, patient-controlled morphine consumption (mg), and pain thresholds to pressure applied to a rib contralateral to the thoracotomy incision.Fifty-two percent of patients reported long-term pain. Early postoperative pain was the only factor that significantly predicted long-term pain. Pain intensity 24 h after surgery, at rest, and after movement was significantly greater among patients who developed long-term pain compared with pain-free patients. A significant predictive relationship was also found at 24 and 48 h using the McGill Pain Questionnaire. Cumulative morphine was comparable for the two groups. Pain thresholds to pressure applied to a rib contralateral to the incision did not differ significantly between the groups.Aggressive management of early postoperative pain may reduce the likelihood of long-term post-thoracotomy pain.

Treatment decisions for the use of opioid analgesics in chronic non-malignant pain are based primarily on survey data, as evidence from well-controlled clinical trials has been lacking. Forty-six patients with chronic non-malignant pain were enrolled in a randomized, double-blind, placebo-controlled evaluation of controlled-release (CR) codeine. Following a 3-7-day diary familiarization period, patients were randomly assigned to 7 days of treatment each with CR codeine q12h or placebo. The CR codeine dose was determined from the consumption of acetaminophen+codeine in the 7 days preceding the study. During both phases, breakthrough pain was treated with acetaminophen+codeine every 4 h as required. Pain intensity was assessed at 08:00 h and 20:00 h using a visual analogue scale (VAS) and a 5-point categorical scale, and rescue analgesic consumption was recorded at the time of use. Thirty patients (17 female, 13 male; mean age: 55.1 +/- 13.4 years) completed the study and were treated with a mean daily CR codeine dose of 273 +/- 78 mg (range: 200-400 mg). CR codeine treatment resulted in significantly lower overall VAS pain intensity scores (35 +/- 18 vs. 49 +/- 16, P = 0.0001), categorical pain intensity scores (1.7 +/- 0.6 vs. 2.2 +/- 0.6, P = 0.0001), and in pain scores by day of treatment and by time of day. Daily rescue analgesic consumption was significantly lower on CR codeine, relative to placebo treatment (3.6 +/- 3.5 vs. 6.1 +/- 3.2 tablets/day, P = 0.0001). There was also a significant reduction in the Pain Disability Index (PDI) on CR codeine, compared to placebo (25.0 +/- 7.7 vs. 35.1 +/- 8.2, P = 0.0001). Patients' and investigators' blinded treatment preference was significantly in favor of CR codeine, relative to placebo (73% vs. 10%, P = 0.0160 and 80% vs. 7%, P = 0.0014, respectively). The incidence of nausea was significantly higher on CR codeine than on placebo (32.6% vs. 11.9%, P = 0.013). Ninety-three percent of patients completing the study requested long-term, open-label treatment with CR codeine. Pain intensity scores at the completion of 19 weeks of long-term evaluation were comparable to those during the double-blind CR codeine treatment. We conclude that treatment with CR codeine results in reduced pain and pain-related disability in patients with chronic non-malignant pain.

Several authors have measured the pharmacokinetic parameters of opioids as they relate to specific pharmacodynamic features intraoperatively (movement with skin incision, autonomic reactivity, rigidity) and postoperatively (analgesia). Noninvasive techniques of administering lipid-soluble opioids, i

Hypoxic pulmonary vasoconstriction (HPV) has not been demonstrated in human single lung anaesthesia in the lateral decubitus position (LDP). The purpose of this study was to determine whether (1) HPV occurs in the non-dependent, non-ventilated lung, and (2) if the infusion of sodium nitroprusside (SNP) inhibits HPV. During intravenous anaesthesia the tracheas of seven patients were intubated with double lumen endotracheal tubes. Standard monitors plus radial and pulmonary arterial catheters were placed. Patients were positioned in the LDP and haemodynamic and gas exchange data were recorded for each of three stages; I: two-lung ventilation, II: single, dependent lung ventilation (1 LV) and III: 1LV with infusion of SNP. In stage II the PaO2 decreased from 531 +/- 42 mmHg to 285 +/- 42 mmHg (P0.05) and Qs/Qt increased from 12.3 +/- 2.7 to 29.0 +/- 6.3% (P0.05). With SNP infusion there was a 30% increase in cardiac index (CI) (P0.05). The SNP infusion was not associated with changes in Qs/Qt or PaO2. This model demonstrates changes in Qs/Qt and PaO2 associated with single-lung ventilation in ASA I and II patients in the LDP but we were unable to demonstrate inhibition of HPV by SNP.

This study was designed to assess the accuracy of end-tidal PCO2 and transcutaneous PCO2 as measurements of arterial PCO2 in extubated, spontaneously breathing patients recovering from general anesthesia. In 30 patients, measurement of arterial transcutaneous, and end-tidal PCO2 were taken simultaneously with body temperature approximately every 15 minutes over a 2-hour period. Arterial PCO2 values were corrected for body temperature. Values for PaCO2 were compared with those for PETCO2 and PsCO2 by linear regression analysis and by calculation of bias +/- precision. Thirty-six percent of the capnogram tracings obtained did not develop a plateau phase. We found poor correlation between end-tidal and arterial PCO2 regardless of the shape of the capnogram tracing, as well as poor correlation between transcutaneous and arterial PCO2. Although the measurements of bias and precision of noninvasive PCO2 monitors in this population are comparable to studies in other populations, we advise caution in relying on the routine use of PETCO2 or PsCO2 for the noninvasive assessment of respiratory depression in extubated, spontaneously breathing patients recovering from general anesthesia.

Summary Current investigation is evaluating several novel techniques of opioid administration for acute (postoperative) analgesia. The underlying concept is to mimic a continuous intravenous infusion and provide stable, nontoxic, therapeutic plasma concentrations for prolonged periods in a simple, easy-to-use fashion. The promising techniques that are currently or likely to be widely available in the near future include buccal and sublingual opioids (morphine, buprenorphine), rectal hydrogel suppositories (morphine), and transdermal opioids (fentanyl, sufentanyl).

Continuous pulse oximetry was performed on 173 adults after general anaesthesia for elective inpatient surgery, throughout their post-anaesthesia care unit (PACU) stay. Supplemental oxygen was administered for greater than or equal to 30 min after arrival and subsequently discontinued before discharge to the ward. The mean and minimum oxyhaemoglobin saturation (SpO2) after discontinuing oxygen were lower than those values achieved during oxygen administration and preoperatively (P less than 0.001). At least one hypoxaemic episode (SpO2 less than or equal to 90% for greater than or equal to 15 sec) occurred in 70 subjects (41%) and 45 of these had a moderate-severe episode (SpO2 greater than or equal to 90% for less than or equal to 2 min or SpO2 less than or equal to 85%). The hypoxaemic episodes began 20 +/- 20 min (range 1-100; median 15) after discontinuing supplemental oxygen. Cyanosis was detected in only four of the 70 patients who desaturated. Factors associated with hypoxaemia were: ASA physical status class; surgical duration greater than or equal to 90 min; and preoperative mean SpO2 less than 95%. Factors not associated with hypoxaemia were: age, sex, % ideal body weight, smoking history, preoperative minimum SpO2, premedication and type of surgery. In conclusion, after discontinuing supplemental oxygen in the PACU, hypoxaemia was common, difficult to detect clinically, and associated with ASA class, surgical duration and preoperative mean SpO2.

This randomized, double-blind study compared the analgesic and respiratory effects of lumbar epidural morphine 5 mg, nalbuphine 10 mg, and nalbuphine 20 mg in repeated doses in patients after thoracotomy; the first dose was administered intraoperatively. Pre-and postoperative monitoring included continuous pulse oximetry, respiratory inductance plethysmography, and repeated arterial blood gas analysis. Postoperatively, visual analogue pain scores, somnolence scores, respiratory rate, and arterial blood gases were determined for 16 h. Preoperatively, episodes of apnea were common during sleep but were not associated with low hemoglobin oxygen saturation or increased arterial carbon dioxide tension (PaCO2). During sleep, some otherwise normal patients had increased PaCO2, and 2 of 15 patients had episodes of hemoglobin oxygen saturation of less than 90%. Postoperatively, 1 and 2 h after arrival in the recovery room, patients who received morphine had lower pain scores than did those who received nalbuphine 10 or 20 mg (P less than 0.05). All 6 patients who received morphine had satisfactory analgesia. Two of 4 patients who received nalbuphine 10 mg and all 5 who received nalbuphine 20 mg were withdrawn from the study because of inadequate analgesia (morphine vs. nalbuphine 10 mg, not significant; morphine vs. nalbuphine 20 mg, P less than 0.01). Two patients who received morphine had persistently increased PaCO2 postoperatively. Two patients who received morphine had episodes of apnea and slow respiratory rate, which were most frequent 6 h after arrival in the recovery room. We conclude that lumbar epidural nalbuphine does not provide adequate analgesia after thoracotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten patients undergoing a thoracotomy were studied for 24 hours postoperatively to determine the effects of a continuous lumbar epidural fentanyl infusion on postoperative pain, arterial blood gases (ABG), respiratory pattern (respiratory inductive plethysmography, RIP), and fentanyl plasma concentration (CONC). Patients served as their own controls because RIP and ABG data were obtained the night prior to surgery during sleep. Epidural fentanyl was administered as a bolus of 1.5 micrograms/kg followed by an infusion of 1.0 micrograms/kg/h started 1 hour after induction. Insufficient analgesia was treated with a bolus of 0.5 micrograms/kg and an infusion increase of 0.25 micrograms/kg/h. Postoperative assessment included RIP, ABG, CONC, and visual analog pain score (PS). The average infusion rate postoperatively was 1.47 +/- 0.08 micrograms/kg/h (114.3 +/- 8.3 micrograms/h). A mean PS of 2.1 +/- 0.3 was achieved; however, there was a delay in attaining this. There was no significant incidence postoperatively of apnea or slow respiratory rate. A significant but clinically insubstantial increase in PaCO2 and decrease in pH occurred. A steady state CONC of approximately 2.0 ng/mL was reached after 9 hours. The PS correlated with CONC in half the patients (0.60 less than r less than 0.86), indicating a systemic component may have contributed to the analgesic effect.

The effectiveness and safety of single-bolus dose esmolol was investigated in patients undergoing rigid bronchoscopy. Fortyfive ASA physical status I to III patients were randomly assigned to receive either placebo, esmolol, 100 mg, or esmolol, 200 mg, in a double-blinded fashion after the induction of anesthesia but prior to rigid bronchoscopy. Heart rate was not significantly greater than preoperative levels in both the esmolol 100- and 200-mg groups for up to 4.5 minutes after the start of rigid bronchoscopy and was significantly lower than placebo in both groups during the bronchoscopy. In contrast, heart rate was significantly increased above preoperative levels for up to 4.5 minutes during bronchoscopy in the placebo group. Systolic blood pressure was significantly lower than placebo at 1.5 minutes in the esmolol 100-mg group and at 1.5 to 2.5 minutes in the esmolol 200-mg group. However, systolic blood pressure was significantly elevated above preoperative values in all the groups during bronchoscopy. Similar results were observed for mean arterial pressure and diastolic blood pressure. No significant effects were noted on ST segment depression (serial 12-lead ECG) during bronchoscopy in any of the groups. A significantly greater number of patients had episodes of ventricular dysrhythmias in the placebo group (54%) compared with the esmolol 200-mg group (0%). No clinically significant episodes of bronchospasm were observed. Therefore, esmolol was found to be very effective in controlling hemodynamics during bronchoscopy.

Ketamine hydrochloride is a well known general anesthetic and short acting analgesic in use for almost 3 decades. The role of the NMDA receptor in the processing of nociceptive input has led naturally to renewed clinical interest in N-methyl-D-aspartate (NMDA) receptor antagonists such as ketamine. This paper reviews the use and efficacy of low-dose ketamine in the management of acute postoperative pain. The literature was obtained from a computer search of the MEDLINE database from 1966 through December 1998. Studies were included for review if they were randomized, prospective, controlled, double-blind and reported pain scores. We evaluate the clinical literature and discuss the efficacy of low-dose ketamine in the management of acute postoperative pain when administered alone or in conjunction with other agents via the oral, intramuscular, subcutaneous, intravenous and intraspinal routes. Low-dose ketamine is defined as a bolus dose of less than 2 mg/g when given intramuscularly or less than 1 mg/kg when administered via the intravenous or epidural route. For continuous i.v. administration low-dose ketamine is defined as a rate of < or =20 microg/kg per min. We conclude that ketamine may provide clinicians with a tool to improve postoperative pain management and to reduce opioid related adverse effects. The evidence suggests that low-dose ketamine may play an important role in postoperative pain management when used as an adjunct to local anesthetics, opioids, or other analgesic agents. Further research is required in the following areas: (a) dose-finding studies for ketamine as an adjunct to opioids and local anesthetics (b) efficacy and optimal route of administration (c) the role of S(+)-ketamine; (d) the influence of ketamine on long-term outcome such as chronic pain (e) long-term physical and chemical stability of mixtures containing ketamine (f) spinal toxicity of ketamine and (g) effects of low-dose ketamine on cognitive and memory functioning after surgery.

The need for routine immediate postoperative chest roentgenography after heart operations has recently been questioned. In this study we investigated the impact of routine postoperative chest roentgenography on treatment instituted in the cardiovascular intensive care unit immediately after heart operations done via median sternotomy. A total of 404 random patients admitted to the cardiovascular intensive care unit underwent clinical (positioning of endotracheal tube, nasogastric tube, and pulmonary artery catheter) and laboratory (oxygenation) assessment by a cardiovascular intensive care unit physician according to a strict protocol. After clinical assessment, chest roentgenography was done for all admitted patients and the findings reviewed by the same physician. Pathologic conditions noted were recorded on the study form together with any required treatment. Eighteen patients (4.5%) out of 404 required intervention because of abnormalities detected by the chest x-ray film but not predicted by the initial physical and laboratory assessment. None of the pathologic conditions detected was life threatening. We conclude that chest roentgenography done on admission to the cardiovascular intensive care unit should be done only if clinical and laboratory assessment indicate the possibility of underlying pathologic conditions that can only be confirmed or diagnosed by chest roentgenography. (J Thorac Cardiovasc Surg 1997;113:130-3)

Background Patients with end-stage liver disease frequently incur large-volume blood loss during liver transplantation associated with mechanical factors, preexisting coagulopathy, and intraoperative fibrinolysis. Methods Between April 1992 and May 1994, the authors of this double-blind, randomized, placebo-controlled study examined the effect of high-dose tranexamic acid (maximum of 20 g) on blood loss and blood product requirements in patients undergoing primary isolated orthotopic liver transplantation. Primary outcome measures were volume of blood loss (intraoperative blood loss and postoperative drainage) and erythrocyte, plasma, platelet, and cryoprecipitate use during surgery and the first 24 h of intensive care unit stay. Results Patients receiving tranexamic acid (n = 25) had less intraoperative blood loss (median, 4.3 l; interquartile range, 2.5 to 7.9; P = 0.006) compared with the placebo group (n = 20; median, 8 l; interquartile range, 5 to 15.8), and reduced intraoperative plasma, platelet, and cryoprecipitate requirements. Median perioperative erythrocyte use was 9 units (interquantile range, 4 to 14 units) in patients receiving tranexamic acid and 13 units (interquantile range, 7.5 to 31 units) in controls (P = 0.03). Total perioperative donor exposure was 20.5 units (interquantile range, 16 to 41 units) in patients receiving tranexamic acid and 43.5 units (interquantile range, 29.5 to 79 units) in controls (P = 0.003). Results for postoperative wound drainage were similar. Hospital stay and need for retransplantation were comparable in both groups. No patient in either group showed clinical evidence of hepatic artery or portal venous thrombosis within 1 month of transplantation. Conclusions High-dose tranexamic acid significantly reduces intraoperative blood loss and perioperative donor exposure in patients with end-stage parenchymal liver disease who are undergoing orthotopic liver transplantation, with marked reductions in platelet and cryoprecipitate requirements.

The purpose of this randomized controlled double blind study was to compare the efficacy of pain relief and the side effects of epidural hydromorphone and morphine in post-Caesarean patients.In all patients, epidural anaesthesia was induced using carbonated lidocaine 2% with 1:200,000 epinephrine and 50 micrograms fentanyl, given in incremental doses. Patients in Group 1 (n = 24) received 0.6 mg hydromorphone and patients in Group 2 (n = 22) received 3 mg morphine after delivery of the infant. Pain, pruritus and nausea were measured using a visual analog scale (at times: baseline, on admission to the recovery room, 3, 6, 12, 18 and 24 hr postoperatively), by the number of requests for additional medications and by an overall satisfaction score.There was no difference between the groups in pain relief of in the incidence and severity of side effects. Pruritus was more pronounced within the first six hours in Group 1 and at 18 hr in Group 2.Hydromorphone provides no clinical benefit over epidural morphine for post operative analgesia following Caesarean section.

The present study tested the hypothesis that patients receiving epidural bupivacaine before surgery would require less morphine postoperatively and/or report less intense pain than patients receiving epidural bupivacaine after incision but before the end of surgery. Forty-two patients (ASA class I-III) scheduled for lower abdominal surgery were randomly assigned to 1 of 2 groups of equal size and prospectively studied using a double-blind, placebo-controlled crossover design. Epidural catheters were placed in the T12-L1 or L1-L2 interspaces pre-operatively, the position of the catheter was confirmed with 3% chloroprocaine with epinephrine 1:200,000, and sensory testing was carried out until levels had receded to below T12. Group 1 received 15 ml of 0.5% epidural bupivacaine injected 35 min before incision followed by 15 ml of epidural normal saline 30 min after incision. Group 2 received 15 ml of epidural normal saline injected 37 min before incision followed by 15 ml of 0.5% epidural bupivacaine 30 min after incision. General anaesthesia was induced with thiopental (4–6 mg/kg) and maintained with N 2 O/O 2 and isoflurane. Paralysis was achieved with pancuronium (0.1 mg/kg). Opioids were not used as pre-medication or during surgery. Postoperative analgesia consisted of patient-controlled (PCA) intravenous morphine. Visual analogue pain scores (VAS) (at rest and after standardized mobilization) did not differ significantly between the 2 groups but McGill Pain Questionnaire (MPQ) pain ratings were significantly lower in group 1 at the 24 and 72 h assessments. Group 1 used significantly less morphine than did group 2 between 12 and 24 h after surgery. Cumulative PCA morphine consumption in group 1 (55.2 ± 4.7 mg) was significantly lower than in group 2 (71.7 ± 6.1 mg) 24 h and 48 h (group 1: 86.8 ± 6.3 mg vs. group 2: 108.9 ± 9.8 mg) after surgery, but not at the 72 h assessment. Reduction in morphine dose at 24, 48 and 72 h amounted to 30%, 25% and 22%, respectively. The results suggest that single-shot pre-emptive epidural local anaesthesia is associated with a short-term morphine-sparing effect which is most pronounced between 12 and 24 h after surgery. Extending the pre-operative blockade into the postoperative period may prolong the initial advantage conferred by pre-emptive epidural local anaesthesia.

Several reports have suggested that preoperative nociceptive block may reduce postoperative pain, analgesic requirements, or both, beyond the anticipated duration of action of the analgesic agents. We have investigated, in a double-blind, placebo-controlled study, pre-emptive analgesia and the respiratory effects of preoperative administration of a multimodal antinociceptive regimen. Thirty patients undergoing thoracotomy were allocated randomly to two groups. Before surgery, the treatment group (n = 15) received morphine 0.15 mg kg-1 i.m. with perphenazine 0.03 mg kg-1 i.m. and a rectal suppository of indomethacin 100 mg, while the placebo group (n = 15) received midazolam 0.05 mg kg-1 i.m. and a placebo rectal suppository. After induction of anaesthesia, the treatment group received intercostal nerve block with 0.5% bupivacaine and adrenaline 1:200,000 (3 ml) in the interspace of the incision and in the two spaces above and two spaces below. The placebo group received identical injections but with normal saline only. The treatment group consumed significantly less morphine by patient-controlled analgesia in the first 6 h after operation, but the total dose of morphine consumed on days 2 and 3 after surgery was significantly greater in the treatment group. There were no differences between the groups in postoperative VAS scores (at rest or after movement), PaCO2 values or postoperative spirometry. However, pain thresholds to pressure applied at the side of the chest contralateral to the site of incision decreased significantly from preoperative values on days 1 and 2 after surgery in both groups. The results of this study do not support the preoperative use of this combined regimen for post-thoracotomy pain.

Background Intermittent self-administered nitrous oxide has long had widespread use as an analgesic in labor, but its efficacy has not been adequately established. Questions about its effect on maternal oxygenation between labor contractions also have been raised. Methods Twenty-six women were recrulted to participate in a randomized, double-blind, cross-over, placebo-controlled study to assess the effect of intermittent nitrous oxide inhalation on labor pain and maternal hemoglobin oxygen saturation (SpO2) during the first stage of labor. Visual analog scale pain scores for each of five consecutive labor contractions were measured after administration of either nitrous oxide or compressed air. Results Mean visual analog scale pain scores for five contractions were 5.1, 5.2, 5.7, 5.2, and 5.6 (nitrous oxide) and 4.9, 5.2, 6.1, 5.6, and 5.7 (compressed air). There were no statistically significant differences in pain when nitrous oxide as compared with compressed air was administered. Pain scores did not differ significantly over time as a function of inhaled substance (F = 0.41, P = 0.53). The mean lowest SpO2 observed between these contractions after self-administration of nitrous oxide and air were 97, 97, 97, 97, and 97% (nitrous oxide) and 97, 96, 96, 96, and 96% (compressed air). SpO2 was significantly higher after nitrous oxide administration (F = 8.8, P = 0.007). Conclusions While intermittent self-administered 50% nitrous oxide in oxygen does not appear to predispose parturient women to hemoglobin oxygen desaturation, its analgesic effect has yet to be clearly demonstrated.

The transdermal therapeutic system (TTS) is a novel technique of drug administration that can mimic long-term continuous intravenous infusions in maintaining stable drug plasma concentrations. Fentanyl, a potent lipid-soluble synthetic opioid, has been incorporated into such a system and has undergone preliminary clinical trials in postoperative patient populations to assess analgesic efficacy and incidence of undesirable side effects (pruritus, nausea and vomiting, urinary retention, respiratory depression). In general, when applied 2 hr preoperatively, a TTS (fentanyl) patch (in different doses) provides moderate-to-good analgesia for a variety of surgical procedures for periods of up to 3 days. Most patients will require small amounts of systemically administered opioids for supplementary analgesia, especially in the first 24 postoperative hr. The incidence of side effects such as nausea and vomiting varies between studies but can be as high as 70%. Clinically significant respiratory depression is rare but was reported in several of the studies. TTS (fentanyl) is a simple and useful technique for the control of postoperative pain.

BackgroundRisk factors of delayed extubation, prolonged intensive care unit (ICU) length of stay (LOS), and mortality have not been studied for patients administered fast-track cardiac anesthesia (FTCA). The authors’ goals were to determine risk factors of outcomes and cardiac risk scores (CRS) for

Background Risk factors of delayed extubation, prolonged intensive care unit (ICU) length of stay (LOS), and mortality have not been studied for patients administered fast-track cardiac anesthesia (FTCA). The authors' goals were to determine risk factors of outcomes and cardiac risk scores (CRS) for CABG patients undergoing FTCA. Methods Consecutive CABG patients undergoing FTCA were prospectively studied. Outcome variables were delayed extubation > 10 h, prolonged ICU LOS > 48 h, and mortality. Univariate analyses were performed followed by multiple logistic regression to derive risk factors of the three outcomes. Simplified integer-based CRS were derived from logistic models. Bootstrap validation was performed to assess and compare the predictive abilities of CRS and logistic models for the three outcomes. Results The authors studied 885 patients. Twenty-five percent had delayed extubation, 17% had prolonged ICU LOS, and 2.6% died. Risk factors of delayed extubation were increased age, female gender, postoperative use of intraaortic balloon pump, inotropes, bleeding, and atrial arrhythmia. Risk factors of prolonged ICU LOS were those of delayed extubation plus preoperative myocardial infarction and postoperative renal insufficiency. Risk factors of mortality were female gender, emergency surgery, and poor left ventricular function. CRSs were modeled for the three outcomes. The area under the receiver operating characteristic curve for the CRS-logistic models was not significantly different: 0.707/0.702 for delayed extubation, 0.851/0.855 for prolonged ICU LOS, and 0.657/0.699 for mortality. Conclusion In CABG patients undergoing FTCA, the authors derived and validated risk factors of delayed extubation, prolonged ICU LOS, and mortality. Furthermore, they developed a simplified CRS system with similar predictive abilities as the logistic models.