Anesthetic recovery after ambulatory laparoscopy: a comparison of isoflurane and alfentanil infusion

Women undergoing ambulatory laparoscopy are known to experience a variety of minor postoperative morbidity which prolongs recovery time and delays discharge. The purpose of this study was to investigate general anesthetic recovery of ambulatory laparoscopy patients receiving two rapid-acting, but disparate, anesthetic techniques. Thirty-one ASA I and II patients between 19 and 44 years of age were randomly divided into two groups. Group I received an isoflurane-based anesthetic, and Group II received an alfentanil continuous infusion. Through analysis of covariance (ANCOVA), Group II recovery scores were found to be significantly higher at T0 (p less than .0001), (p less than .0001), T15 (p less than .001), T30 (p less than .01) and T45 (p less than .02). There was no difference between groups at T60, at which time all patients received the maximum score of 10. No other factor besides anesthetic technique significantly affected recovery scores. Group II patients spent an average of 166 minutes (+/- 59 standard deviation) in the recovery room in comparison with 192 minutes (+/- 32 standard deviation) for Group I patients. Despite this finding, an ANCOVA determined that only presence of postoperative vomiting significantly affected recovery room time (p less than .03). Further research is indicated in the endeavor to reduce postoperative morbidity of this patient population.     

Continuous subcutaneous insulin infusion during general anesthesia: a case report

Care of the patient with diabetes mellitus presents numerous challenges to the anesthesia practitioner. There is no perfect way to care for these patients nor are any 2 patients with diabetes exactly alike. With the advent of subcutaneous insulin pumps, the anesthesia practitioner has another tool to assist him or her in giving high quality care. This case study describes the anesthesia care provided to a patient with type 1 diabetes who wore his continuous subcutaneous insulin infusion (CSII) pump during general anesthesia for surgical repair of a herniated lumbar disk. Importantly, the anesthesia plan involved a collaborative effort with the patient. Blood glucose levels were stable throughout the perioperative period. Little or no extra work was required of the CRNA. This case showed that the CSII could be used to minimize perioperative fluctuations in blood sugar. Postoperatively, the patient expressed a high degree of satisfaction with the anesthetic.     

Respiratory effects of intraoperative alfentanil infusion in post-abdominal hysterectomy patients: A comparison of high versus low dose

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.     

瑞芬太尼微泵注入防治硬膜外麻醉术中牵拉反应临床观察

目的观察小剂量瑞芬太尼用于防治硬膜外麻醉术中牵拉反应的临床效果。方法选择ASAⅠ~Ⅱ级择期肾脏手术患者30例,分为观察组(瑞芬太尼组)和对照组(杜非组)各15例。手术开始时对照组静脉注射杜冷丁50mg和异丙嗪25 mg,观察组静脉注射瑞芬太尼0.5μg/kg,然后以0.06~0.13μg/(kg.m in)微泵注入至关腹。常规吸氧并监测SBP、DBP、ECG、SpO2,观察并记录术中BP、HR、SpO2变化。结果两组在切开肌肉腹膜、手术牵拉肾脏时SBP、DBP、HR差异有显著性意义(P(0.05)。结论小剂量瑞芬太尼微泵注入辅助硬膜外麻醉可有效地减轻术中牵拉反应。     

Pharmacokinetics and pharmacodynamics of vecuronium administered by bolus and infusion during halothane or balanced anesthesia

Vecuronium was administered to two patient groups as a single intravenous dose, 60 micrograms/kg, combined with an infusion, 1 microgram/min/kg. Anesthesia was maintained for the first group with a halothane-nitrous oxide technique; the second group received fentanyl-barbiturate-tranquilizer-nitrous oxide. As the infusion ended, plasma vecuronium concentrations were 0.34 (+/- 0.10) microgram/ml for the halothane group and 0.32 (+/- 0.07) microgram/ml for the fentanyl group, associated with 93% (+/- 8) and 88% (+/- 10) twitch depression, respectively. Vecuronium plasma concentration-time data were combined with the simultaneous intensities of neuromuscular blockade to model the kinetic-dynamic values for each patient. For the halothane group the steady-state volume was 0.21 (+/- 0.04) L/kg, the clearance was 2.9 (+/- 0.1) ml/min/kg, and the elimination half-life was 100 (+/- 36) minutes; for the fentanyl group these were 0.20 (+/- 0.08) L/kg, 3.2 (+/- 0.1) ml/min/kg, and 84 (+/- 43) minutes, respectively. Plasma concentrations associated with 50% blockade averaged 0.2 microgram/ml for both groups. Neither the pharmacokinetics nor the pharmacodynamics of vecuronium in humans differed between these two patient groups.     

The effect of muscle movement on the electroencephalogram during anesthesia with alfentanil

Using aperiodic analysis, we examined the impact on the electroencephalogram (EEG) of muscle activity from opiate-induced rigidity with alfentanil. We compared two groups of patients, one receiving alfentanil with neuromuscular blocking agents and the other group receiving no relaxants. The alfentanil-induced muscle rigidity exerted a noticeable effect on the EEG, with a moderate effect on total power at 1 Hz; a marked effect on the total number of waves, cumulative percent power at 3 Hz, and average power at 17 to 19 Hz; and a striking effect on F90, the frequency below which 90% of the power resides. The presence of electromyographic (EMG) noise in the EEG consistently altered the variables derived from the EEG, so that anesthetic depth appeared less than it actually was. This was true in spite of the fact that we gave slightly more alfentanil in the group not receiving a relaxant. Although the observed muscle activity was greater than that usually seen clinically, and may have differed qualitatively, the results do serve as a warning that muscle noise can interfere with the EEG. Currently, there is no computerized technique that will reject or account for this noise, and we must depend on observation to recognize the EMG patterns within the EEG, either with the raw recording or with a detailed analysis (such as aperiodic analysis), and to compensate for this noise if possible. Techniques that average the EEG or that present a single number have difficulty providing this information. These results do not detract from the usefulness of the EMG contained in EEG recordings as a supplementary or complementary indicator of anesthetic lightness.     

An electroencephalographic comparison of alfentanil with other narcotics and with thiopental

Using aperiodic analysis, we compared the EEC produced by alfentanil with the EEGs produced by two other opiates—fentanyl and sufentanil—on the one hand and with the EEG produced by a barbiturate—thiopental—on the other hand. Alfentanil and thiopental were injected over 1 minute: fentanyl and sufentanil were injected over 10 to 15 minutes. From the aperiodic analysis we derived up to seven single-number variables computed over 30- or 60-second epochs. All the opiates induced EEGs that were qualitatively similar to each other, although the maximum or minimum values tended to be greater and the time course more rapid with alfentanil than with the other two opiates. This finding may have been related to the fact that we injected relatively more alfentanil and administered it more rapidly. The EEGs produced by alfentanil and thiopental differed markedly, both qualitatively and quantitatively. The total power at 1 Hz and cumulative power at 3 Hz went to higher peak values with alfentanil, the latter tending to decrease with thiopental. The total number ot waves per epoch went to lower peak values with alfentanil; there was little change with thiopental. The frequency below which 90% ot the power resides went to considerably lower peak values with alfentanil than with thiopental. Finally, total power at 10 to 12 Hz (alpha waves; and average power at 17 to 19 Hz (beta waves) went to very high peak values with thiopental, but decreased with alfentanil. In spite ot differences in the opiate studies in the timing ot injection and the relative amount ot drug injected, the variables that proved useful in their response to fentanyl and sutentanil also proved useful with altentanil. In contrast, almost all variables showed a difference in response between alfentanil and thiopental. Supported in part by Janssen Pharmaceutics, Inc. Pisacataway, NJ, and by Diatek Corporation, and the Veterans Administration Medical Center, San Diego, CA.     

Continuous infusion of beta-lactams

PURPOSE OF REVIEW: Continuous infusion of beta-lactam antibiotics is becoming increasingly popular. The background and current clinical evidence are discussed. Tools to apply continuous infusion are analyzed. RECENT FINDINGS: One randomized controlled trial in an ICU setting and two nonrandomized controlled trials have shown continuous infusion to be more beneficial than intermittent infusion. One randomized controlled trial in chronic obstructive pulmonary disorder patients, however, showed no difference between the two treatments. The stability of most beta-lactams for use during continuous infusion has been documented. SUMMARY: Killing of bacteria by beta-lactam antibiotics is maximal at around four times the minimum inhibitory concentration in vitro. To ensure an optimal effect when treating severe infections, free unbound concentrations at or above four times the minimum inhibitory concentration should be maintained. Although continuous infusion has been demonstrated to be superior in animal studies, randomized clinical trials have failed to confirm this in humans, primarily because of suboptimal design. A better designed randomized clinical trial, set up as a pilot study, recently demonstrated a favorable outcome with continuous infusion. A major issue during continuous infusion is the stability of the antibiotic, which may limit its application. The calculation of the infusion rate necessary to obtain the desired free drug concentration is relatively straightforward.     

Continuous intrathecal fentanyl infusion for postoperative analgesia

Following inadvertent dural puncture during epidural catheter placement, a 20 gauge polyethylene catheter was placed in the intrathecal space, and continuous spinal anesthesia with hyperbaric bupivacaine was administered intraoperatively to supplement general anesthesia. Following surgery, a continuous intrathecal fentanyl infusion (0.2 mcg/kg/hr) was administered to provide postoperative analgesia. The child was awake and comfortable throughout this time and required no supplemental analgesic agents. Although epidural catheters are still our preferred method of analgesia, intrathecal fentanyl infusion is one alternative when inadvertent dural puncture occurs.     

Continuous intravenous infusion of morphine for severe dyspnea

We describe eight patients who had terminal lung cancer causing severe dyspnea unrelieved by oxygen, nonnarcotic drugs, or intermittent bolus narcotics. We treated these patients with continuous intravenous infusion of morphine, beginning with bolus IV injections of 1 or 2 mg of morphine every 5 to 10 minutes until the patient reported relief. A continuous morphine infusion was then started, with the hourly dose equal to 50% of the cumulative bolus dose. Vital signs, degree of sedation, and blood gases were serially followed. Six patients achieved good dyspnea relief, one had moderate relief, and one had a poor response. Variable changes were noted in the PaO2, whereas PaCO2 steadily increased in five of seven patients, and pH decreased in six. There was little change in systolic blood pressure or pulse, and only one individual had less than 10 respirations per minute. The major side effect of treatment was sedation, treated by temporarily discontinuing morphine until the patients' mental status improved and then restarting the infusion at a 50% lower hourly morphine dose. Mean time of study was 30 hours (range 16 to 87 hours). Seven of the eight study patients died during treatment. Whether morphine therapy shortened survival is uncertain. We conclude that continuous morphine infusion is effective therapy for severe dyspnea. The treatment is ethically justified. Relief of suffering is the primary goal of therapy, and less risky treatments are unavailable.     

Continuous epidural anesthesia for elective cesarean hysterectomy

Continuous lumbar epidural anesthesia was the primary anesthetic technique used for 25 patients having elective cesarean hysterectomy at Duke University Medical Center during a 12 1/2-year interval. Seven patients (28%) with initially satisfactory epidural anesthesia required intraoperative induction of general orotracheal anesthesia because of patient discomfort and resultant suboptimal operating conditions. Careful patient selection and preparation, expertise in administering continuous epidural anesthesia, and understanding of the demands of the operative procedure are essential when planning epidural anesthesia for cesarean hysterectomy.     

Continuous subcutaneous infusion of narcotics

Many cancer patients will experience pain. However, this pain can be controlled through the appropriate administration of narcotics. While narcotics can be taken orally and titrated to achieve a level of patient comfort, complications or the progression of disease may prohibit the use of oral analgesics. Continuous subcutaneous infusion of narcotics represents an alternate approach to pain management which can be effective in the management of cancer pain.     

Continuous ampicillin infusion as an alternative to intermittent infusion for adult inpatients: A case series

Intravenous ampicillin has been extensively used for various kinds of infections for more than fifty years. This drug is administered intermittently, which can result in missed or delayed drug administration and sleep interruption that can have a negative impact on the quality of life during hospitalization. Continuous infusion may solve these concerns. We reviewed the cases of five patients who were treated with continuous ampicillin infusions in our hospital. The ampicillin serum concentrations were from 11.3 to 32.8 μg/mL, which was above the ampicillin MICs of the causative organisms, ≤0.06 to 4 μg/mL. Although the dosages given of ampicillin varied in each case, the serum concentrations showed a strong correlation with creatinine clearance (r² = 0.91). All the patients improved at the time of discharge, or transfer to another hospital, with no significant complications during the continuous infusion. Continuous ampicillin infusion could be a better alternative for frequent intermittent infusion for adult inpatients with infections due to ampicillin-susceptible organisms.