Doxapram and aminophylline on bispectral index under sevoflurane anaesthesia: a comparative study.

BACKGROUND AND OBJECTIVE: To evaluate and compare the effect of two clinically available central nervous system stimulants, namely doxapram and aminophylline on arousal from sevoflurane anaesthesia and bispectral index. METHODS: This randomized, double-blind, placebo-controlled, prospective study was conducted in 90 adult females, ASA I-II, scheduled for elective lower abdominal surgeries at Taipei Medical University Hospital. At 5 min before the completion of surgery, under sevoflurane anaesthesia, patients were divided into three groups to receive doxapram 1 mg kg(-1), aminophylline 2 mg kg(-1) or saline placebo intravenous. Standard vital signs, end-tidal CO(2), end-expiratory sevoflurane concentration, bispectral index and neuromuscular blockade were measured plus clinical parameters of recovery from general anaesthesia. RESULTS: Compared with the control group, patients receiving doxapram or aminophylline showed a similarly faster recovery from sevoflurane anaesthesia correlated with increase in bispectral index. CONCLUSION: Intravenous administration of doxapram 1 mg kg(-1) or aminophylline 2 mg kg(-1) hastened the early recovery from sevoflurane anaesthesia. The arousal effect of aminophylline and doxapram appears to be similar.

Effect of adding ketorolac to intravenous morphine patient-controlled analgesia on bowel function in colorectal surgery patients--a prospective, randomized, double-blind study.

BACKGROUND: Postoperative ileus (PI) is the transient impairment of bowel motility due to surgical trauma and the associated physiological responses. Postoperative ileus results in patient discomfort, increases gastrointestinal risks, prolongs hospital stay and increases medical expenses. In this study, we investigated the effect of patient-controlled analgesia (PCA) morphine with or without ketorolac on bowel functions in patients after colorectal surgeries. METHODS: A total of 79 patients who received elective colorectal resection were randomly allocated into two groups receiving either intravenous PCA morphine (M group) or intravenous PCA morphine plus ketorolac (K group). Recovery of bowel functions (bowel movement, passage of flatus, and soft diet intake), pain scores, morphine consumption, time for first ambulation, and opioid-related side-effects were recorded. RESULTS: Patients in the K group received 29% less morphine than patients in the M group with comparable pain scores. The first bowel movement (1.5 [0.7-1.9] vs. 1.7 [1.0-2.8] days, P < 0.05) and the first ambulation (2.2 +/- 1.0 vs. 2.8 +/- 1.2 days, P < 0.05) were significantly earlier in the K group than in the M group. The time of the first flatus passing, the first intake of soft diet, and duration of hospital stay were not significantly different between the two groups. CONCLUSIONS: The results of this study suggest that addition of ketorolac to intravenous morphine PCA provides an opioid-sparing effect but has limited benefit in shortening the duration of bowel immobility and time to first ambulation. These findings imply that postoperative ileus is attributable to multiple factors in addition to morphine consumption.

Prediction of the distance from skin to epidural space for low-thoracic epidural catheter insertion by computed tomography.

BACKGROUND: It may be clinically useful to predict the depth of the epidural space. METHODS: To investigate the accuracy of preoperative abdominal computed tomography (CT) in prediction of the distance for low-thoracic epidural insertion, a single group observational study was conducted in 30 male patients undergoing elective major abdominal surgery requiring epidural analgesia for postoperative pain relief. Using the paramedian approach, low-thoracic epidural insertion at T10-11 interspace was performed with a standardized procedure to obtain an actual insertion length (AIL). According to the principles of trigonometry, an estimated insertion length (EIL) was calculated as 1.26 times the distance from skin to epidural space measured from the preoperative abdominal CT. RESULTS: The mean (SD) EIL and AIL were 5.5 (0.7) and 5.1 (0.6) cm, respectively, with a significant correlation (r=0.899, P<0.01). The EIL tended to have a higher value than the AIL (0.4 (0.3) cm). There were significant correlations of both EIL and AIL with weight (P<0.01), BMI (P<0.01), and body fat percentage (P<0.01), but not with height (P>0.05). CONCLUSIONS: We conclude that the preoperative abdominal CT is helpful in prediction of the distance for low-thoracic epidural insertion using the paramedian approach.

The influence of different sub-type delta opioid receptors in nerve growth factor-induced neuronal differentiation in rat pheochromocytoma PC12 cell.

The impairment of neuronal differentiation for long-term opioid drug-exposed infants is a serious problem and there are several speculated mechanisms. We have previously reported that altering the endogenous delta opioid receptor by long-term interaction with its antagonist augmented the nerve growth factor (NGF)-induced neuronal differentiation of rat pheochromocytoma PC12 cells. In this study using subtype-specific antagonist, we present data showing further that type 2 delta opioid receptor (delta(2)-DOR) is the receptor on the PC12 cells participating in the progression of neuronal differentiation upon NGF-stimulation. Unlike the delta(2)-DOR, alteration of type 1 DOR (delta(1)-DOR) activity by delta(1)-DOR-specific antagonist appeared to be toxic for the PC12 cells. The different influence of the subtypes of delta opioid receptors in the neuronal differentiation of the PC12 cells suggests that each subtype of opioid receptor may trigger different biological activities in vivo.

Transesophageal echocardiography in the anesthetic management of total hip arthroplasty.

Total hip arthroplasty is a common procedure in the elderly and thromboembolism continues to be a cause of mortality and morbidity associated with this procedure. When properly diagnosed and treated the mortality rate from pulmonary embolism can be reduced significantly. Transesophageal echocardiograpic (TEE) detection of central pulmonary artery thromboemboli in patients with severe pulmonary embolism has been reported to have a sensitivity of 96.7% and a specificity of 88%. However TEE is not universally available due to its cost and expertise that is required. Taking into consideration its cost/effectiveness we suggest that in patients undergoing the cement type of total hip arthroplasty who are cardiopulmonary compromised, debilitated or elderly the use of TEE is indicated.

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.

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

UNLABELLED: The combination intrathecal fentanyl (25 microg) 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 microg) to the intrathecal combination of fentanyl (25 microg) and bupivacaine (2.5 mg) would prolong labor analgesia. By using the combined spinal epidural technique, 95 healthy primiparous laboring women in early labor received 2 mL of one of the two intrathecal study solutions, either FB (n = 48): fentanyl (25 microg) and bupivacaine (2.5 mg); or FBM (n = 47): fentanyl (25 microg) and bupivacaine (2.5 mg) plus morphine (150 microg). The mean duration of labor analgesia was significantly longer in the FBM group than in the FB group (252 +/- 63 min vs 148 +/- 44 min, P < 0.01). There were no significant differences between the two groups regarding the sensory levels, the incidence of nausea, vomiting, pruritus, hypotension, or operative delivery. In conclusion, the addition of 150 microg of morphine to the intrathecal combination of fentanyl plus bupivacaine prolonged the duration of labor analgesia duration without increasing adverse effects. IMPLICATIONS: The addition of morphine (150 microg) to intrathecal fentanyl (25 microg) and bupivacaine (2.5 mg) prolongs the duration of labor analgesia duration without increasing adverse effects.

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 closure, the patients were randomly allocated to receive 5 mg x 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 x ml(-1) tramadol i.v. 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.

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

PURPOSE: To compared the clinical efficacy of tramadol and morphine using a patient-controlled analgesia (PCA) delivery system. METHODS: In 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 < or =4). Equivalent volumes containing either 30 mg x ml(-1) tramadol or 1 mg x 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. RESULTS: Patients 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). CONCLUSION: Tramadol 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.

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.

Epidural phenylephrine attenuates hypotension induced by alkalinized lidocaine epidural anesthesia.

UNLABELLED: In this double-blinded, randomized study, we examined the hemodynamic effects of lumbar epidural injection of alkalinized lidocaine with phenylephrine in 81 patients undergoing inguinal herniorrhaphy. Patients assigned to four equal groups received 20 mL of alkalinized lidocaine (17 mL of 2% lidocaine + 3 mL of 7% sodium bicarbonate) with one of four doses of phenylephrine: 0 (Group 1), 50 (Group 2), 100 (Group 3), or 200 microg (Group 4) injected via a lumbar epidural catheter. Blood pressure, heart rate, and skin temperature on the foot were recorded every 5 min for 1 h after injection and were compared among groups. Hypotension was defined as mean arterial pressure < 80% of baseline. The incidence of hypotension was 45%, 55%, 35%, and 15% in Groups 1-4, respectively. Patients in Group 4 showed the smallest reduction in blood pressure compared with Groups 1 and 2 (one-sided Fisher's exact test, P < 0.05). We conclude that the 200-microg dose of epidural phenylephrine (1:100,000 concentration) reduced the incidence of hypotension after epidural anesthesia with alkalinized lidocaine. IMPLICATIONS: Hypotension after epidural anesthesia is common in general clinical practice. Phenylephrine administered epidurally in combination with alkalinized lidocaine may reduce the incidence of hypotension.

Nasopharyngeal electrode recording of somatosensory evoked potentials as an indicator in brain death.

Median nerve somatosensory evoked potentials were recorded in 28 comatose patients, eight of whom were progressing from coma to eventual brain death and in 11 brain dead patients using electrodes over the scalp, neck and nasopharynx (nasopharyngeal electrode). This recording technique was used to assess the different derivation of brainstem P14 wave activity. It showed that in the midfrontal scalp to the nasopharynx derivation a clear P14 was present in all comatose patients. This component disappeared during the passage from coma to brain death. In a separate group, simultaneous direct recordings in the vicinity of the dorsal column nuclei and with a nasopharyngeal electrode were made in five patients undergoing neurosurgical procedures at the craniocervical junction with the same somatosensory evoked potential monitor. We found that the P14 recorded with the nasopharyngeal electrode in the neurosurgical patients corresponded in latency and morphology with the P14 recorded directly on the surface of the craniocervical junction and more specifically in the vicinity of the nucleus cuneatus. The nasopharyngeal electrode provides non-invasive access to the ventral brainstem at the medullo-pontine level and the disappearance of the P14 shows a clear sign of involvement of the craniocervical junction in brain dead patients. Our study showed that with a simple montage the nasopharyngeal electrode is an effective non-invasive monitor for brainstem activity and can be used as an early diagnostic indicator of brainstem death.

Local anesthetic effect of tramadol, metoclopramide, and lidocaine following intradermal injection.

BACKGROUND AND OBJECTIVES: We observed clinically that tramadol and metoclopramide appear to have local anesthetic action. Tramadol is a central-acting analgesic. Metoclopramide is a commonly used antiemetic. The local anesthetic effect of tramadol in reducing propofol injection pain has never been mentioned, although it was speculated with metoclopramide. METHODS: We conducted a double-blind, placebo-controlled study by injecting tramadol or metoclopramide intradermally in 10 healthy volunteers (5 men, 5 women; age 25-56 years). Each subject received 0.5 mL of four solutions in random order on the volar side of the forearm. These solutions were 25 mg tramadol, 5 mg metoclopramide, 5 mg lidocaine, and 0.5 mL normal saline. Pain on injections and the degree of local anesthesia (tested by pinprick, light touch, and cold) at each site was reported on a 0-3 scale at designed time intervals. RESULTS: Like 1% lidocaine, tramadol and metoclopramide demonstrated loss of sensation for pinprick, light touch, and cold for 15 minutes after intradermal injection (P < .01 ). CONCLUSIONS: Intradermal tramadol or metoclopramide can produce local anesthetic effect.

Effects of Brazilin on induction of immunological tolerance by sheep red blood cells in C57BL/6 female mice.

Brazilin was examined for its effects on the induction of immunological tolerance. Brazilin was administered to C57BL/6 female mice for 2 consecutive days before the immunization with high dose SRBC (10(9) cells) which can produce immunological tolerance. Delayed type hypersensitivity, IgM plaque forming cells, ConA induced IL-2 production and mitogen- or antigen-induced proliferation of lymphocytes were measured as evaluation parameters. Administration of brazilin prior to immunization could keep the DTH and IL-2 production almost optimally immunized levels. Brazilin also inhibited the elevation of non-specific suppressor cell activity. ConA induced proliferation of splenocytes in high dose SRBC immunized mice was significantly decreased by pretreatment of brazilin. And this might be one of the reason for augmentation of DTH by brazilin. However, IgM plaque forming cells were not affected by the treatment of brazilin. These results indicate that brazilin prevents the induction of immunological tolerance caused by high dose SRBC by suppressing the elevation of suppressor cell activity and by inhibiting the decrease in IL-2 production in C57BL/6 female mice.

Application of spinal pain mapping in the diagnosis of low back pain--analysis of 104 cases.

BACKGROUND: Low back pain is probably the most common pain problem seen in a general pain clinic and the cause of low back pain can be enigmatic at times. Often the pain sources are difficult to identify with the conventional diagnostic modalities. Spinal pain mapping is a sequence of well organized nerve block procedures. We undertook this study to evaluate the usefulness of this modality in diagnosing low back pain of uncertain etiology. METHODS: In this prospective study, 104 consecutive adult patients who underwent spinal pain mapping were examined and analyzed. All patients had intractable low back pain of undetermined etiology after medical history, physical examination and 4-view roentgenographic evaluation of the lumbar spine had been undertaken to locate it. In addition, 41 patients (39%) had one or more of the following tests done, which included CT, MRI, EMG/NC but all failed to delineate the causes of the pain. All patients failed to respond to the conservative therapies. RESULTS: With pain mapping the source of pain was found to be caused by sacro-iliac joint in 6%, lumbar nerve root in 20%, facet joint in 24%, combined lumbar nerve root and facet disease in 24%, internal disc disorder in 7%, combined facet and sacro-iliac joint in 4% and lumbar sympathetic dystrophy in 2% of patients. Pain mapping failed to demonstrate the causes of the pain in the remaining 13% of the patients. CONCLUSIONS: Considering the difficult nature of this group of patients, spinal pain mapping provided a useful functional approach to the diagnosis of low back pain with obscure etiology in 87% of patients in our series.

The peripheral analgesic effect of meperidine in reducing propofol injection pain is not naloxone-reversible.

BACKGROUND AND OBJECTIVES: Meperidine is frequently used in general anesthesia and perioperative analgesia. In addition to its opioid action, meperidine possesses some local anesthetic properties. A preliminary study using the tourniquet venous retention technique found meperidine to be more effective in reducing propofol injection pain than fentanyl or morphine, both of which were slightly better than placebo. This study was undertaken to evaluate whether this peripheral analgesic effect of meperidine is affected by naloxone. METHODS: In a randomized, double-blind manner, after venous occlusion with a tourniquet, meperidine 40 mg was given intravenously to patients in group A (n = 31), meperidine 40 mg followed by naloxone 0.04 mg to group B (n = 32), meperidine 40 mg followed by naloxone 0.2 mg to group C (n = 30), and normal saline placebo to group D (n = 30). The venous retention of drug(s) was maintained for 1 minute, followed by tourniquet release and intravenous administration of propofol 100 mg. Pain assessment was made immediately after the propofol injection. RESULTS: All three groups given meperidine had significantly less propofol injection pain (P < .01 ) than the group given saline placebo, and there was no difference among groups A, B, and C. CONCLUSION: The peripheral analgesic effect of meperidine in reducing propofol injection pain is not mediated by its opioid activity.

Enhancement of analgesic effect of intrathecal neostigmine and clonidine on bupivacaine spinal anesthesia.

BACKGROUND AND OBJECTIVES: Intrathecal administration of neostigmine has been shown to produce analgesia in both animals and humans. The concurrent administration of intrathecal neostigmine and clonidine has been reported to produce no neurotoxicity in sheep. The purpose of the present study was to evaluate the efficacy and safety of the combining intrathecal neostigmine and clonidine for the relief of pain in patients after cesarean delivery. METHODS: After giving their consents, 80 parturients who were scheduled for cesarean delivery during spinal anesthesia were enrolled by a double-blind randomized design into four groups: bupivacaine group (n = 20) received intrathecal (i.t.) 10 mg bupivacaine; bupivacaine + neostigmine group (n = 19) received i.t. 10 mg bupivacaine + 50 microg neostigmine; bupivacaine + clonidine group (n = 20) received i.t. 10 mg bupivacaine + 150 microg clonidine; and bupivacaine + both (n = 21) received i.t. 10 mg bupivacaine + 50 microg neostigmine + 150 microg clonidine. The maximum spread of anesthesia, duration of analgesia and motor block, vital signs, and incidence of adverse effects were recorded for 14 hours postinjection. Fifty milligrams intramuscular meperidine was given as a rescue analgesic whenever patient's pain score was greater than 5/10 by the visual analog scale. RESULTS: The demographic data were similar for all four groups. Bupivacaine + both group had a significantly higher maximum spread of anesthesia of 23.3 +/- 2.9 segments than bupivacaine group of 20.5 +/- 2.9 segment. Bupivacaine + both group showed a later onset of postsurgical pain of 6.5 +/- 1.5 hours as compared to bupivacaine group of 1.3 +/- 0.6 hours. The pain score in bupivacaine + both group was significantly lower than that of bupivacaine group during the first 10 hours. The 24-hour meperidine consumption also was lower in bupivacaine + both group than that of bupivacaine group. However, motor block was significantly prolonged from 3.5 +/- 1.1 hours in bupivacaine group to 7.1 +/- 1.6 hours in bupivacaine + both group. In addition, other side effects such as nausea and vomiting and dizziness were significantly increased in bupivacaine + both group. CONCLUSION: Our study showed that the combination of 150 microg i.t. clonidine and 50 microg neostigmine provided longer postsurgical analgesia than with either drug used alone. However, this combination also produced significantly more adverse effects of prolonged motor block and nausea and vomiting. A further study combining the two study drugs but using a lower dose of i.t. neostigmine (e.g., 25 microg) is recommended.

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

UNLABELLED: Using venous retention with a tourniquet (70 mm Hg), we performed a randomized, double-blind study to assess the efficacy of I.V. pretreatment with fentanyl, morphine, meperidine, or lidocaine in reducing propofol injection pain. Immediately after venous occlusion with a tourniquet, I.V. fentanyl 150 microg (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 I.V. 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 approximately meperidine > morphine approximately 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.

Intradermal injection of tramadol has local anesthetic effect: a comparison with lidocaine.

BACKGROUND: We observed that intravenous retention of tramadol with a pneumatic tourniquet on the arm inflated to 70 mmHg for one minute could effectively reduce the subsequent propofol injection pain. Tramadol is a central-acting analgesic. The local analgesic effect of tramadol on reducing propofol injection pain is not well known. METHODS: To explore this problem we conducted a double-blind study on intradermal injections of tramadol 25 mg, lidocaine 5 mg and normal saline (all in 0.5 ml volume) which were given to each of the 10 healthy volunteers on the forearm at random. Pain on injections and the degree of local analgesia to pinprick, light touch and cold at each injection site were scored on a 0-4 scale at designated intervals. RESULTS: 5% tramadol, similar to 1% lidocaine, rendered loss of sensation to pin prick, light touch and cold for 30 min after intradermal injection as compared with normal saline (p < 0.01). CONCLUSIONS: We concluded that intradermal injection of tramadol or lidocaine can produce local anesthetic effect.

Comparison of epidural butorphanol plus clonidine with butorphanol alone for postoperative pain relief.

BACKGROUND: Epidural butorphanol has been shown to produce effective analgesia with less side effects than that of morphine but relatively short duration. Clonidine, an alpha 2-adrenergic agonist, has been reported to provide [corrected] pain relief by epidural administration. Furthermore, epidural clonidine has been shown to potentiate the analgesic effect of epidural morphine. The present study was undertaken to evaluate the analgesic and side effects of epidural administration (Ep) of butorphanol and clonidine. METHODS: After giving their consents, 60 adult patients scheduled for abdominal surgeries were enrolled in this study. Prior to anesthesia induction, indwelling lumbar epidural catheters were placed in all patients who then received general anesthesia with inhalation anesthetic without narcotic analgesics. In the postoperative period, when the patients first complained of pain, they were divided into 2 equal groups of 30 patients each in a randomized and double blinded fashion with Group I receiving Ep butorphanol 0.5 mg and Group II receiving Ep butorphanol 0.5 mg plus clonidine 75 micrograms. All patients were observed for pain relief, sedation, vital signs, arterial blood gas studies and adverse effects for 12 h. RESULTS: Onset of pain relief with epidural butorphanol began at 5 min and peaked at 20-30 min with a duration of action lasting 4-6 h. The combination of butorphanol and clonidine had numerically superior pain relief than that of butorphanol for the first 30 min but it did not attain statistical significant difference. The duration of action with the combination group was similar to that of butorphanol alone. Incidence of adverse effects were similar in both groups except that hypotension and more pronounced sedation were observed in Group II. CONCLUSIONS: Our study showed that the addition of clonidine to epidural butorphanol did not enhance its analgesic effect in any significant manner nor did it reduce the adverse effects. This combination does not seem to offer any advantage for clinical use.