Martin S. Mok

The analgesic effect of fentanyl, morphine, meperidine, and lidocaine in the peripheral veins: a comparative study.

Using venous retention with a tourniquet (70 mm Hg), we performed a randomized, double-blind study to assess the efficacy of IV pretreatment with fentanyl, morphine, meperidine, or lidocaine in reducing propofol injection pain. Immediately after venous occlusion with a tourniquet, IV fentanyl 150 micro g (Group A, n = 35), morphine 4 mg (Group B, n = 35), meperidine 40 mg (Group C, n = 35), 2% lidocaine 3 mL (Group D, n = 35), or normal saline 3 mL (Group E, n = 35; as placebo control) was given to adult patients. The venous retention of the drug was maintained for 1 min, followed by tourniquet release and IV administration of propofol 100 mg. Pain assessment was made immediately after the propofol injection. Lidocaine and meperidine significantly reduced propofol injection pain more than placebo (P < 0.05), but there were more side effects in the meperidine group. Fentanyl and morphine reduced the intensity of propofol injection pain (P < 0.05) and had some effect in reducing the incidence of propofol injection pain, but the difference did not reach statistical significance. The order of efficacy was lidocaine [nearly =] meperidine > morphine [nearly =] fentanyl. We postulate that the peripheral analgesic effect of these opioid is due to their local anesthetic activity. Implications: Propofol, a commonly used anesthetic, often causes pain on injection. Given as venous retention pretreatments 1 min before propofol, meperidine and lidocaine were found to significantly reduce the propofol injection pain, whereas fentanyl and morphine only slightly reduced the propofol injection pain. (Anesth Analg 1998;86:382-6)

Intravenous lidocaine and ephedrine, but not propofol, suppress fentanyl-induced cough

PurposeThe aim of this study was to evaluate the effectiveness of lidocaine, propofol and ephedrine in suppressing fentanyl-induced cough.MethodsOne hundred and eighteen patients were randomly assigned into four groups and the following medications were given intravenously: patients in Group I (n = 31) received normal saline 2 mL, Group II (n = 29) received lidocaine 2 mg · kg−1, Group III (n = 30) received propofol 0.6 mg · kg−1 and Group IV (n = 28) received ephedrine 5 mg. At one minute after the study medication, fentanyl 2.5 μg · kg−1 was given intravenously within two seconds. The occurrence of cough and vital sign profiles were recorded within two minutes after fentanyl bolus by an anesthesiologist blinded to study design.ResultsSixty-five percent of patients in the placebo group had cough, whereas the frequency was significantly decreased in Groups II(14%) and IV (21%). Although a numerically lower frequency of cough was noted in Group III (37%), it was not statistically different from that of the placebo group. SpO2 decreased significantly in patients of Group III compared to placebo; one patient experienced hypoxemia necessitating mask ventilation. Patients in Group III showed a decrease in heart rate and systolic blood pressure (2 beats · min−1 and 8 mmHg vs baseline). Patients in Group IV showed an increase in both measurements (5 beats · min−1 and 8 mmHg vs baseline). No truncal rigidity was observed throughout the study.ConclusionsIntravenous lidocaine 2 mg · kg−1 or ephedrine 5 mg, but not propofol 0.6 mg · kg−1, was effective in preventing fentanyl-induced cough. The results provide a convenient method to decrease fentanyl-induced cough.RésuméObjectifÉvaluer l’efficacité de la lidocaïne, du propofol et de l’éphédrine dans la suppression de la toux induite par le fentanyl.MéthodeCent dix-huit patients ont été répartis au hasard en quatre groupes et ont reçu: Groupe l (n = 31), 2 mL de solution saline; Groupe II (n = 29), 2mg · kg−1de lidocaïne; Groupe III (n = 30), 0,6 mg · kg−1 de propofol et Groupe IV (n = 28), 5 mg d’éphédrine. À une minute après la médication expérimentale, 2,5 μg · kg−1 de fentanyl iv ont été administrés en moins de deux secondes. L’occurrence de toux et les profils des signes vitaux ont été enregistrés par un anesthésiologiste impartial pendant les deux minutes qui ont suivi l’administration de bolus de fentanyl.RésultatsSoixante-cinq pour cent des patients du groupe placebo ont eu de la toux, tandis que la fréquence a significativement diminué dans les Groupes II (14 %) et IV (21 %). Même si une fréquence de toux numériquement plus basse a été notée dans le Groupe III, elle n’était pas statistiquement différente de celle du groupe placebo. La SpO2 a diminué significativement chez les patients du Groupe III comparé au groupe placebo; un patient a présenté de l’hypoxémie nécessitant une ventilation au masque. Les patients du Groupe III ont subi une baisse de la fréquence cardiaque et de la tension artérielle systolique (2 battements · min−1 et 8 mmHg vs les mesures de base). Ceux du Groupe IV ont présenté une augmentation de ces deux paramètres (5 battements · min−1 et 8 mmHg vs les mesures de base). Aucune rigidité tronculaire n’a été observée pendant l’étude.ConclusionL’administration iv de 2 mg · kg−1 de lidocaïne ou de 5 mg d’éphédrine, mais non de 0,6 mg · kg−1 de propofol, a été efficace pour prévenir la toux induite par le fentanyl. Les résultats offrent une méthode pratique de diminuer la toux induite par le fentanyl.

Comparison of patient-controlled analgesia (PCA) with tramadol or morphine

PurposeTo compared the clinical efficacy of tramadol and morphine using a patient-controlled analgesia (PCA) delivery system.MethodsIn a prospective, randomized, double blind study, we evaluated 80 adult patients scheduled for elective hip or knee arthroplasty with general inhalational anesthesia. When patients complained of pain in the recovery room, patients were randomized to receive either tramadol or morphine by titration in 30 min to achieve analgesia (VAS ≤ 4). Equivalent volumes containing either 30 mg · ml−1 tramadol or 1 mg · ml−1 morphine were used for PCA with a lockout interval of 10 min. The patients were followed six-hourly for 48 hr for VAS, satisfaction rate, analgesic dose, and side effects.ResultsPatients obtained adequate analgesia with either drug. More patients had very good satisfaction scores in the morphine group in the recovery room (43% vs 23%,P < 0.05) and at 24 hr (40% vs 20%,P < 0.05) than those in the tramadol group. More nausea was evident in the tramadol group (48% vs 11% in recovery room and 28%vs 12% in 24 hr,P < 0.05) than in the morphine group. Vomiting was also more (28% vs 5% in recovery room, 15% vs 3% in 24 hr,P < 0.05). Morphine produced more sleepiness (45% vs 23% in recovery room,P < 0.05 and 35%vs 15% in 24 hr,P < 0.05).ConclusionTramadol PCA can provide effective analgesia following major orthopedic surgery provided sufficiently high doses are given for loading and by patient demand. However, the incidence of nausea/vomiting is also higher causing decreased satisfaction.RésuméObjectifComparer l’efficacité clinique du tramadol et de la morphine en utilisant un système d’analgésie contrôlée par le patient (ACP).MéthodeLors d’une étude prospective, randomisée et en double aveugle, nous avons évalué 80 adultes dont l’arthroplastie de la hanche ou du genou avait été prévue avec une anesthésie générale d’inhalation. À la salle de réveil, les patients répartis au hasard ont reçu, quand ils éprouvaient de la douleur, du tramadol ou de la morphine selon un dosage permettant d’atteindre l’analgésie (EVA ≤ 4) en 30 min. Des volumes équivalents contenant 30 mg · ml−1 de tramadol ou 1 mg · ml−1 de morphine ont été utilisés pour l’ACP, qui comprenait une période réfractaire de 10 min. Les patients ont été revus à toutes les six heures pendant 48 h pour l’enregistrement des scores de l’EVA, de la satisfaction, de la dose d’analgésique et des effets secondaires.RésultatsLes patients ont obtenu une analgésie suffisante avec l’un ou i’autre médicament. Un plus grand nombre de patients a été très satisfait dans le groupe ayant reçu de la morphine à la salle de réveil (43 % vs 23 %,P < 0,05) et à 24 h (40 % vs 20 %,P < 0,05) que ceux du groupe ayant reçu le tramadol. Il y a eu davantage de nausées dans le groupe du tramadol (48 % vs 11 % dans la salle de réveil et 28 % vs 12 % à pendant les 24 premières heures, P < 0,05) que dans le groupe de la morphine. Les vomissements ont été également plus fréquents (28 % vs 5 % en salle de réveil, 15 % vs 3 % pendant les 24 premières heures, P < 0,05). La morphine a produit plus de somnolence (45 % vs 23 % en salle de réveil,P < 0,05 et 35 % vs 15 % pendant 24 h,P < 0,05).ConclusionLACP avec le tramadol peut assurer une analgésie efficace à la suite d’une intervention orthopédique importante, pourvu que des doses suffisamment élevées soient administrées en dose d’attaque et à la demande du patient. Cependant, l’incidence de nausées et de vomissements est aussi plus élevée avec le tramadol, ce qui en diminue l’attrait.

Sequential cardiorespiratory patterns of anesthetic induction with ketamine in critically ill patients

Hemodynamic and O2 transport effects of ketamine anesthesia were evaluated in 22 critically ill patients. After placement of radial and pulmonary artery catheters, simultaneous measurements were made of cardiac output, intravascular pressures, arterial and mixed venous gases, saturations, pH, and Hct; cardiorespiratory values then were calculated for a preinduction control period and sequentially at frequent intervals over a 15-min observation period. In general, there was an early progressive increase in HR, cardiac index (CI), arterial and venous pressures, stroke work, and O2 delivery (Do2); O2 consumption (Vo2) and O2 extraction (O2 Ext) decreased. In general, ketamine produced an inotropic cardiac response, but these responses were not uniform; a relatively small percentage had reduced pressures, flow, and reduced myocardial performance that were related to hypovolemia and associated medical conditions.

The addition of morphine prolongs fentanyl-bupivacaine spinal analgesia for the relief of labor pain.

The combination intrathecal fentanyl (25 μg) and bupivacaine (2.5 mg) provides effective labor analgesia for approximately 90 minutes. The purpose of this prospective, randomized, double-blinded investigation was to determine if the addition of morphine (150 μg) to the intrathecal combination of fen

Intraoperative loading attenuates nausea and vomiting of tramadol patient-controlled analgesia.

Purpose: To evaluate the adverse effect profile of tramadol by patient-controlled analgesia (PCA) with administration of the loading dose either intraoperatively or postoperatively.Methods: Sixty adult patients scheduled for elective abdominal surgery were enrolled into this prospective, randomized, double blind study. The patients were anesthetized in a similar manner. At the beginning of wound dosure, the patients were randomly allocated to receive 5 mg·kg−1 tramadol (Group 1) or normal saline (Group 2). In the post-anesthesia care unit (PACU), when patients in either group complained of pain, 30 mg·ml−1 tramadol iv were given every three minutes until visual analogue scale (VAS) 3, followed by tramadol PCA with bolus dose of 30 mg and five minute lockout interval. Pain control and adverse effect assessments were done in the PACU and every six hours for 48 hr post drug by an independent observer.Results: The loading dose was 290±45 mg in Group 1 and 315±148 mg in Group 2. In PACU, more nausea/vomiting both in terms of incidence (13/30, 43% vs 2/30, 6.6%,P<0.05) and severity (nausea/vomiting score 2.5±2.0 vs 0.2±0.6,P<0.05) was observed in patients with postoperative loading than in those with intraoperative loading of tramadol.Conclusion: Administering the loading dose of tramadol during surgery decreases the nausea/vomiting associated with high dose of tramadol and improves the quality of tramadol PCA in the relief of postoperative pain.RésuméObjectif: Évaluer le profil des effets indésirables du tramadol, utilisé pour l’analgésie contrôlée par le patient (ACP) après une dose de charge peropératoire ou postopératoire.Méthode: Ont participé à l’étude prospective, randomisée et à double insu 60 patients adultes admis pour une intervention abdominale planifiée. L7rsanesthésie a été similaire pour tous. Au début de la fermeture de la plaide chirurgicale, les patients, répartis au hasard, ont reçu 5 mg·kg−1 de tramadol (Groupe 1) ou un soluté physiologique (Group 2). À la salle de réveil, on a administré sur demande 30 mg·ml−1 de tramadoliv à toutes les trois minutes jusqu’à ce que l’échelle visuelle analogique (EVA) indique ⩾ 3. Puis, le tramadol ACP a été donné en bolus de 30 mg alternant avec une période réfractaire de cing minutes. Le contrôle de la douleur et les effets négatifs ont été évalués par un observateur impartial à la salle de réveil et toutes les six heures pendant 48 h après l’administration du médicament.Résultats: La dose de charge était de 290±45 mg dans le Groupe 1 et de 315±148 mg dans le Groupe 2. On a noté plus de nausées et de vomissements, en termes d’incidence (13/30, 43 % vs 2/30, 6,6 %;P<0,05) et de sévérité (score de 2,5±2,0 vs 0,2±0,6;P<0,05) dans le cas de la dose de charge postopératoire de tramadol que dans le cas de la dose peropératoire.Conclusion: L’administration peropératoire d’une dose de charge de tramadol permet de r eduire les nausées et vomissements associés à de fortes doses de tramadol et améliore la qualité analgésique postopératoire de ce médicament en ACP.

Combination of low-dose epidural morphine and intramuscular diclofenac sodium in postcesarean analgesia

: Epidural morphine is used for postcesarean analgesia, and nonsteroidal antiinflammatory drugs are frequently administered to relieve uterine cramps after vaginal delivery. To assess the efficacy of a combination of low-dose epidural morphine and intramuscular diclofenac sodium in postcesarean analgesia, a double-blind, randomized study was conducted. Epidural anesthesia was given to 120 parturients who were randomly allocated into four treatment groups: group A received normal saline solution, 10 mL epidurally and 3 mL intramuscularly (IM); group B received 10 mL of epidural saline solution and 75 mg (3 mL) of diclofenac IM; group C received 2 mg of morphine in 10 mL of epidural saline solution and 3 mL of saline solution IM; and group D received 2 mg of morphine in 10 mL of epidural saline solution and 75 mg of diclofenac IM. Epidural injections were given after delivery of the placenta, and IM injections were given on arrival in the recovery room. Verbal analogue pain scores were recorded at 2, 4, 8, 12, 18, and 24 h after epidural injection. Subjective scores of overall pain relief were also recorded at 24 h. Results showed that scores of overall pain relief were significantly better in group D compared with group A, B, or C (P less than 0.05). Groups A and B required more supplemental meperidine than groups C and D. None of the subjects in group D requested supplemental analgesia. Compared with the other three groups, group D experienced a better analgesic effect for both wound pain and uterine cramping pain from 4 to 18 h (P less than 0.05). Incidence of nausea or vomiting, or both, and pruritus occurred more frequently in groups C and D compared with group A or B (P less than 0.05). No bradypnea was observed during the study period. Diclofenac alone was not effective in postcesarean analgesia.(ABSTRACT TRUNCATED AT 250 WORDS)

EEG-bispectral index changes with ketamine versus thiamylal induction of anesthesia.

BACKGROUND The EEG-Bispectral Index (BIS) is a processed EEG information that has been validated as a means to measure the hypnotic effect of anesthetic drugs. In this study we evaluated the BIS changes in induction of anesthesia with ketamine in comparison with that of thiamylal. METHODS Forty ASA class I and II adult female patients undergoing elective gynecologic surgeries were enrolled into this randomized, prospective study. No premedication was given to the patient. In each patient EEG was recorded continuously from the frontal electrodes using Aspect A-1050 monitor after his arrival at the operating room. Blood pressure and heart rate were also recorded throughout the surgery. After steady baseline recordings of all necessary parameters having been accomplished Group K patients (n = 20) were given an induction dose of ketamine 1.5 mg/kg i.v., whereas Group T patients (n = 20) received thiamylal 5 mg/kg i.v. When loss of consciousness was ascertained, intubation was performed after administration of succinylcholine 1 mg/kg i.v. and anesthesia was maintained with isoflurane-nitrous oxide-oxygen. Demographics, BIS values, HR, BP were analyzed and compared. RESULTS The demographics were comparable between the two groups. Both groups showed a mean value of BIS of 96 with comparable BP and HR before induction. After study drug the post-induction BIS for ketamine was 94 as against 51 for thiamylal (P < 0.05), 91 against 43 post-succinylcholine (P < 0.05), 92 against 53 post-intubation (P < 0.05) and 45 against 37 five min after isoflurane. BIS remained below 60 throughout the entire course of anesthesia and returned to above 95 on emergence in both groups. None of the patients reported awareness, recall, delirium or hallucination during anesthesia. CONCLUSIONS Ketamine-induced dissociative anesthesia produces persistently elevated BIS index which is different from thiamylal and those reported with other conventional anesthetic agents. The established range of BIS index appears not to be applicable in patients under ketamine anesthesia. Monitoring the depth of ketamine anesthesia remains to be a challenging problem.

Predicting hypotensive episodes during spinal anesthesia with the application of artificial neural networks

Hypotension is one of the most frequent adverse effects of spinal anesthesia. Several factors might be related to the occurrence of hypotension. Predictions of the hypotensive event, however, had been addressed by only a few authors using logistic regression (LR) models. Artificial neural networks (ANN) are pattern-recognition tools that can be used to detect complex patterns within data sets. The purpose of this study was to develop the ANN-based predictive model to identify patients with high risk of hypotension during spinal anesthesia. From September 2004 to December 2006, the anesthesia records of 1501 patients receiving surgery under spinal anesthesia were used to develop the ANN and LR models. By random selection 75% of data were used for training and the remaining 25% of data were used as test set for validating the predictive performance. Five senior anesthesiologists were asked to review the data of test set and to make predictions of hypotensive event during spinal anesthesia by clinical experience. The ANN model had a sensitivity of 75.9% and specificity of 76.0%. The LR model had a sensitivity of 68.1% and specificity of 73.5%. The area under receiver operating characteristic curves were 0.796 and 0.748. The ANN model performed significantly better than the LR model. The prediction of clinicians had the lowest sensitivity of 28.7%, 22.2%, 21.3%, 16.1%, and 36.1%, and specificity of 76.8%, 84.3%, 83.1%, 87.0%, and 64.0%. The computer-based predictive model should be useful in increasing vigilance in those patients most at risk for hypotension during spinal anesthesia, in allowing for patient-specific therapeutic intervention, or even in suggesting the use of alternative methods of anesthesia.

Patient-controlled analgesia with morphine plus lysine acetyl salicylate.

UNLABELLED Using a patient-controlled analgesia (PCA) delivery system, we evaluated the clinical advantages and disadvantages of morphine PCA compared with morphine plus lysine acetyl salicylate (LAS), a soluble aspirin. After major orthopedic surgery, 50 adult patients were enrolled in a prospective, randomized, and double-blinded study. When a patient in the recovery room complained of pain, an initial dose of morphine or the morphine/LAS mixture was titrated to achieve analgesia of visual analog score < or = 3 in 30 min. An equivalent volume PCA dose of either morphine 1 mg/mL or morphine 0.5 mg + LAS 90 mg/mL was used with a lockout interval of 10 min. Pain score, patient satisfaction, vital signs, and adverse effects were observed for 48 h. Adequate analgesia (visual analog scale score < or = 3) was achieved with either drug. Morphine consumption in the morphine/LAS group was significantly less than in morphine group (13.9 vs 18.4 mg in 24 h and 24.3 vs 32.4 mg in 48 h). Significantly more sedation was evident with the morphine group (P < 0.05). We conclude that injectable LAS can be used as an effective and safe adjuvant to morphine for PCA. This combination reduces dose requirements of morphine and hence some of its adverse effects. IMPLICATIONS Injectable aspirin could be used as an effective and safe adjuvant to morphine for patient-controlled analgesia. This combination reduces the dose requirement of morphine and therefore some of the morphine-related untoward effects.