Background and objective: Diabetes mellitus associated with hypertension often causes perioperative complications. The α1-adrenoceptor antagonist/5-hydroxytryptamine-1A receptor agonist urapidil is an approved drug used in hypertension and hypertensive emergencies. 5-Hydroxytryptamine-1A (5-HT1A) receptor agonists impair glucose metabolism. To evaluate a possible dose-dependent hyperglycaemic effect of urapidil due to its 5-HT1A receptor agonistic properties, the effect of three doses of urapidil on hyperglycaemia in the streptozotocin diabetic rat was investigated.

Methods: Male Wistar-Kyoto rats were made diabetic by streptozotocin and randomly allocated to the following daily treatments for 7 days (n = 6 each): urapidil 6 mg kg−1, urapidil 20 mg kg−1, urapidil 60 mg kg−1, insulin 4 IU kg−1 subcutaneously. One diabetic group and one non-diabetic healthy group served as controls.

Results: Treatment for 7 days with urapidil 20 mg kg−1 and urapidil 60 mg kg−01 reduced mean glucose concentrations significantly (urapidil-20: 15.6 ± 1.1 mmol L−1P = 0.023; urapidil-60: 15.8 ± 0.8 mmol L−1, P = 0.04) compared with diabetic controls (20.9 ± 0.8 mmol L−1), whereas those after urapidil 6 mg kg−1 were similar to diabetic controls. Insulin treatment normalized blood glucose concentrations.

Conclusions: The α1-adrenoceptor antagonist/5-HT1A receptor agonist urapidil has no hyperglycaemic effect on experimental diabetes mellitus, even in high doses, despite its 5-HT1A receptor agonistic properties.

Background and objective: To investigate the interactions of postoperative pain and endocrine stress response, three groups of 21 patients each with total knee arthroplasty were compared in a randomized, prospective design. For postoperative pain management, a three-in-one block, an epidural catheter analgesia or an intravenous patient-controlled analgesia was used.

Methods: After standardized balanced anaesthesia, the pain intensity was measured by a visual analogue scale (VAS). For detection of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone and cortisol in the plasma, blood samples were taken at six time points before and up to 180 min after the start of pain therapy. In addition, systolic arterial pressure, heart rate, partial arterial oxygen saturation, nausea, vomiting and satisfaction of the patients were recorded.

Results: Within 15 min after the start of pain therapy, VAS in all groups was similarly reduced from >40 mm to a range <10 mm (P < 0.001). Initially, all endocrine stress variables exceeded the normal range. Epidural anaesthesia led to a significant decrease of epinephrine and norepinephrine concentrations, while an increase was observed in the group with patient-controlled analgesia, and the decrease in patients with the three-in-one block was less than in patients receiving epidural anaesthesia (P = 0.001). Differences in antidiuretic hormone, adrenocorticotropic hormone and cortisol were less pronounced. Systolic arterial pressure decreased significantly in all groups, particularly in patients with epidural anaesthesia. Partial arterial oxygen saturation and the incidence of nausea and vomiting were comparable. All patients were satisfied with the methods used.

Conclusions: All methods of pain management led to sufficient analgesia, but they were not accompanied by an adequate reduction in endocrine stress response. Thus, postoperative pain is only a secondary stressor and sufficient analgesia with subjective well-being does not prove a stress-free state. With regard to the reduction of sympathoadrenergic stress response, epidural anaesthesia is superior to the three-in-one block and patientcontrolled analgesia. Epidural anaesthesia is recommended particularly for high-risk patients with hypertension, coronary heart disease and diabetes mellitus. In these patients, the reduction of a ‘hidden’ endocrine stress response in addition to prevention of pain is of special interest.

Background and objective: The study was designed to evaluate whether the administration of sevoflurane in 100% oxygen for anaesthesia during Caesarean section would improve fetal and neonatal oxygenation compared with the administration of sevoflurane with 50% nitrous oxide in oxygen.

Methods: The randomized, single-blind controlled study examined 24 mothers, ASA I-II, at term undergoing Caesarean section who were allocated to receive sevoflurane in either 100% oxygen (n = 13) or 50% nitrous oxide in oxygen (n = 11). General anaesthesia was induced in both groups with thiopental 4–5 mg kg−1 followed by succinylcholine 1.5 mg kg−1 to facilitate tracheal intubation. Parturients received sevoflurane given either in 100% O2 or in a 50 : 50 nitrous oxide and oxygen mixture, using 0.5-1.0% progressive incremental dosing up to 1.5–2.0 MAC. Non-invasive fetal oxygen saturation was measured between induction to delivery, and umbilical artery and vein PaO2 were evaluated at birth.

Results: Intraoperative fetal oxygen saturation increased in all patients after maternal 100% oxygen administration (P < 0.01). Maternal hyperoxygenation significantly increased the umbilical vein and umbilical artery PaO2 and the umbilical artery SaO2 at birth (P < 0.0001).

Conclusions: Maternal hyperoxygenation significantly improves fetal as well as neonatal oxygenation.

Background and objective: Cognitive dysfunction has been reported after general anaesthesia, but its assessment is time consuming and difficult to evaluate. This pilot study assessed the feasibility of using the Sustained Attention to Response Test to assess 35 ASA I-II adults (mean age 31.6 yr) undergoing day case surgery under general anaesthesia, and 25 ASA I-II adults (mean age 47.8 yr) undergoing day case surgery under local anaesthesia.

Methods: The Sustained Attention to Response Test was performed before surgery and repeated 2 h after surgery.

Results: When patients repeated the test after surgery under local anaesthesia, the number of incorrect responses increased, but reaction times decreased (P < 0.05). Following general anaesthesia, the number of incorrect responses increased (P < 0.05), but reaction times remained unchanged.

Conclusions: The Sustained Attention to Response Test is simple to administer and may be a useful tool when comparing different anaesthetic techniques and their effects on postoperative deficits in sustained attention.

Background and objective: Computers offer the potential for the assessment of children who have difficulties in communication and cannot describe pain using conventional approaches. Such approaches must be reliable and valid. As a preliminary step towards this goal, the validity and reliability of a computer-assisted pain assessment for children (MacInterview) was assessed using children with no known disabilities who had undergone surgery.

Methods: MacInterview uses body outlines and a range of different pain representations with scaling for size and intensity, and associated emotion. Following piloting with non-clinic children, the experience of acute postoperative pain was assessed for 30 children undergoing adenotonsillectomy or tonsillectomy the day following surgery using the MacInterview and three existing standardized assessment measures. Each child self-reported their current experience of postoperative pain on two occasions 30 min apart, and retrospectively on pain the previous evening in the immediate postoperative period.

Results: Analyses indicated good performance of MacInterview, showing positive correlations between 0.65 and 0.88 with standardized pain-intensity measures, and test-retest reliability was 0.9. Face validity was high, and children enjoyed the procedure.

Conclusions: The procedure shows promise and is likely to merit further development for children showing difficulties in communication.

Background and objective: We assessed the analgesic efficacy of postoperative epidural infusions of ropivacaine 0.1 and 0.2% combined with sufentanil 1 μg mL−1 in a prospective, randomized, double-blinded study.

Methods: Twenty-two ASA I—III patients undergoing elective total-knee replacement were included. Lumbar epidural blockade using ropivacaine 0.75% was combined with either propofol sedation or general anaesthesia for surgery. After surgery, the epidural infusion was commenced. Eleven patients in each group received either an epidural infusion of ropivacaine 0.1% with 1 μg mL−1 sufentanil (Group 1) or ropivacaine 0.2% with 1 μg mL−1 sufentanil (Group 2) at a rate of 5–9 mL h−1. All patients had access to intravenous pirinatrimide (piritramide) via a patient-controlled analgesia (PCA) device.

Results: Motor block was negligible for the study duration in both groups. There was no significant difference with the 100 mm visual analogue scale (VAS) scores, with the consumption of rescue analgesia or with patient satisfaction. Patients in Group 1 experienced significantly less nausea (P < 0.05) than those in Group 2. Both treatment regimens provided effective postoperative analgesia with only a minimal use of supplemental opioid PCA.

Conclusions: We recommend the use of ropivacaine 0.1% with 1 μg mL−1 sufentanil for postoperative analgesia after total knee replacement as it provides efficient pain relief with no motor block of the lower limbs. In addition, compared with 0.2% ropivacaine with sufentanil, the mixture reduces local anaesthetic consumption without compromise in patient satisfaction or VAS scores. Patients even experience less nausea.

Background and objective: The aim was to determine if the intravenous administration of sufentanil or clonidine before the induction of anaesthesia could obtund the increase of intraocular pressure associated with rapid-sequence induction.

Methods: Thirty-two ASA I—II patients with no history of eye illness scheduled for elective non-ophthalmic surgery were randomly assigned to receive either sufentanil 0.05 µg kg−1 i.v. (Group A, n = 15) or clonidine 2 µg kg−1 i.v. (Group B, n = 17) prior to induction. General anaesthesia was induced with thiopental (5 mg kg−1) followed by succinylcholine 1 mg kg−1 to facilitate tracheal intubation. The general anaesthetic technique was standardized in both groups. Intraocular pressure was measured using the Schioetz tonometer just before the succinylcholine administration (t0), just before tracheal intubation (t1) and immediately after intubation (t2). Mean arterial pressure and heart rate were recorded at the same time intervals.

Results: Intraocular pressures were similar in both groups at t0, but the sufentanil group had significantly lower values compared with the clonidine group just before (t1) and immediately after tracheal intubation (t2).

Conclusions: Sufentanil is effective in blunting the increase in intraocular pressure caused by rapid-sequence induction with succinylcholine, while clonidine did not seem to have any effect in intraocular pressures just before (t1) and just after (t2) intubation.

Background and objective: The efficiency of operating room times can be significantly improved using rapid changes between operative procedures. We performed a retrospective analysis using electronic anaesthesia charts that compared anaesthesia-related times between the three most frequently performed types of anaesthesia (for orthopaedic surgery) to evaluate the potential for a quicker turn-around between cases.

Methods: A total of 5614 anaesthetic procedures in trauma-related orthopaedic surgery were performed from 1997 to 1999. All were documented with an automatic record-keeping system. Data were compared for intravenous anaesthesia with the laryngeal mask airway, balanced anaesthesia with tracheal intubation and regional anaesthesia. The primary outcome measure was the time needed for emergence from anaesthesia after the end of surgery. Statistical evaluation was performed with matched triples for all three types of anaesthesia (155 triples for ambulatory surgery, 249 triples for in-patient care).

Results: For ambulatory surgery, the induction time was significantly shorter for general anaesthesia (23.7 min for intravenous anaesthesia, 22.7 min for balanced anaesthesia techniques) compared with regional anaesthesia (27.2 min). The time from the end of the surgical procedure to transfer of the patient out of the operating room was shortest for regional anaesthesia (6.3 min) compared with intravenous anaesthesia (9.0 min) and balanced anaesthesia (12.5 min) techniques. Results were comparable for in-patients: regional anaesthesia required significantly longer for its induction, but less time for patient discharge from the operating room.

Conclusions: The use of a regional anaesthesia technique or one involving intravenous anaesthesia in combination with the laryngeal mask airway may lead to a reduction in discharge time compared with a balanced anaesthesia technique with endotracheal intubation. Thus, improved use of resources may be achieved.

Background and objective: Unilateral paravertebral nerve blockade has been reported to produce excellent afferent nerve block, reduce the incidence of postoperative nausea and vomiting, and reduce hospital stay following inguinal hernia repair. The aim was to compare the use of bilateral paravertebral blocks to regular general anaesthesia for ventral hernia repair.

Methods: Sixty patients were prospectively allocated to receive either bilateral paravertebral nerve blockade (midazolam for block; supplemented with light intraoperative sedation if needed) or general anaesthesia for ventral hernia repair. The end-points of the study were length of hospital stay, postoperative analgesia (visual analogue scale, supplemental opioid requirement) and incidence of postoperative nausea and vomiting.

Results: The duration of hospital stay was observed to be shorter in patients handled with bilateral paravertebral nerve blockade (2.3 [SD 1.3] days) compared with patients receiving general anaesthesia (4.1 (3.0) days). Paravertebral analgesia resulted in both lower visual analogue scores and a significantly reduced need for supplemental opioid administration during the first 48 h postoperatively compared with general anaesthesia (P < 0.001). The rate of postoperative nausea and vomiting in the paravertebral nerve blockade group was only 3.3%, while 26.7% of patients in the general anaesthesia group suffered from postoperative nausea and vomiting (P < 0.05). Paravertebral nerve blockade was associated with good patient acceptance in 90% of patients.

Conclusions: Bilateral paravertebral blockade combined with light intravenous sedation was superior to general anaesthesia for ventral hernia repair. Paravertebral blockade was associated with shorter hospital stay, improved analgesia and less postoperative nausea and vomiting. It is suggested that this technique deserves more widespread use in patients undergoing ventral hernia repair.

Background and objective: The α2-adrenoceptor agonist clonidine has potent central antinociceptive properties. The study was designed to investigate the effects of the combined subarachnoid administration of clonidine and prilocaine on spinal block and postoperative analgesia for the transurethral resection of tumours in the urinary bladder.

Methods: The controlled, prospective, double-blind study enrolled 40 patients scheduled for elective transurethral resection of bladder tumours under spinal anaesthesia with prilocaine. Patients were randomly assigned to receive an intrathecal injection of prilocaine 75 mg alone (control group) or in combination with clonidine 75 µg. We assessed haemodynamic changes (non-invasive arterial pressure, heart rate), pulse oximetry, the upper level of block, the onset and duration of sensory and motor block, postoperative analgesia and any adverse effects.

Results: There were no statistically significant differences in demographic data, heart rate, onset time or the levels of sensory or motor block. Analgesia lasted significantly longer in the clonidine group (498.4 ± 226.9 versus 187.2 ± 103.1 min; P < 0.05). The duration of motor block was longer in the clonidine group (165.5 ± 30.6 min) than in the control group (139.7 ± 40.4 min; P < 0.05) and the duration of sensory block was also longer in the clonidine group (157.3 ± 24.5 min) than in the control group (137.2 ± 31.2 min; P < 0.05). Fewer patients in the recovery room needed metamizol (dipyrone) in the clonidine group (5%) than in the control group (50%). Arterial pressure decreased significantly in the clonidine group 75-135 min after the block.

Conclusions: The addition of clonidine 75 µg to prilocaine 75 mg for subarachnoid anaesthesia increased the duration of sensory and motor block and reduced the need for additional postoperative analgesics by providing excellent analgesia for about 8 h during recovery from transurethral resection of bladder tumours.

Background and objective: The study aimed to evaluate and improve airway management in the prehospital setting, i.e. physicians working on board ambulances. A quality control programme focusing on anaesthesia was instituted to improve the time taken to perform endotracheal intubation.

Methods: All consecutive patients requiring tracheal intubation were prospectively analysed before (first period) and after the training programme focusing on anaesthetic protocols for tracheal intubation (second period). The number of attempts at laryngoscopy, the time taken to achieve tracheal intubation, the difficulties encountered and the related complications of the anaesthetic technique were recorded. At the end of the first period, the results were reported to the whole staff of the unit and the anaesthesia protocols were then modified by introducing succinylcholine into the induction sequence, as part of a training programme.

Results: Two-hundred-and-eighty patients were evaluated (97 in the first period, 183 in the second). All patients were successfully intubated in both periods. The percentage of difficult intubations (as assessed by the physician) was lower in the second period (20 versus 35%, respectively; P < 0.01). The success rate at the first attempt was significantly higher (74% [68–80] 95% CI versus 55% [45–65] 95% CI, P < 0.01) and the duration of intubation was significantly shorter in the second period than in the first (1.4 ± 3.2 vs. 4.1 ± 6.7 min, respectively; P < 0.001). The incidence of complications (hypoxaemia, laryngospasm, bronchospasm) was lower in the second period (15 versus 31%, P < 0.01).

Conclusions: The time to perform tracheal intubation can be improved by the introduction of succinylcholine into the prehospital anaesthetic protocol. Rapid sequence induction should be taught as a way of improving tracheal intubation in the prehospital setting.

Background and objective: Magnesium has antinociceptive effects in animal and human models of pain. These effects are primarily based on the regulation of calcium influx into the cell. The aim of this study was to determine whether perioperative infusion of magnesium would reduce postoperative pain and anxiety.

Methods: Twenty-four patients, undergoing elective hysterectomy, received a bolus of 30 mg kg−1 magnesium sulphate or the same volume of isotonic sodium chloride solution intravenously before the start of surgery and 0.5 g h−1 infusion for the next 20 h. Intraoperative and postoperative analgesia were achieved with fentanyl and morphine respectively. Patients were evaluated pre- and postoperatively for anxiety.

Results: Fentanyl consumption and total morphine requirements were significantly decreased in the magnesium group compared to the control group. Postoperative anxiety scores and sedation were similar between groups.

Conclusions: Continuous magnesium infusion, including the pre-, intra-, and postoperative periods reduces analgesic requirements. These results demonstrate that magnesium can be an adjuvant for perioperative analgesic management.

Background and objective: The epidural and subarachnoid spaces should be identified at the first attempt, since multiple punctures increase the risk of postdural puncture headache, epidural haematoma and neural trauma. The study aimed to describe the predictors of successful neuraxial blocks at the first attempt.

Methods: After institutional Review Board approval, 1481 patients undergoing spinal or epidural anaesthesia were prospectively enrolled. For each block we recorded: gender, age, height, weight, body habitus, anatomical landmarks (palpability of the spinous processes), spinal anatomy, patient positioning, premedication, needle type and gauge, approach, spinal level of the block, and the provider’s level of experience. Retrieval of cerebrospinal fluid or loss of resistance to saline or air identified the subarachnoid and epidural spaces, respectively. The outcome variable was the first attempt success or failure (whether or not the needle was correctly located with one skin puncture and produced adequate surgical anaesthesia). Backward stepwise logistic regression tested its association with the other variables.

Results: The first-attempt rate of success was 61.51%. Independent predictors (Odds ratio, 95% confidence limits) were the quality of anatomical landmarks (1.92 (1.57; 2.35)), the provider’s level of experience (1.24 (1.15; 1.33)) and the adequacy of patient positioning (3.84 (2.84; 5.19)).

Conclusions: The successful location of the subarachnoid or the epidural space at the first attempt is influenced by the quality of patients’ anatomical landmarks, the adequacy of patient positioning and the provider’s level of experience.

Background and objective: Drug mixtures containing sufentanil may be unstable owing to absorption into the drug reservoirs of patient-controlled epidural analgesia systems that contain polyvinylchloride. The stability of sufentanil in a mixture of ropivacaine 0.2% in a 750 mL reservoir was therefore investigated.

Methods: During simulated epidural infusions of 5 mL h−1 at 25°C, sufentanil concentrations were measured for 96 h. Samples were taken from the reservoir and from the end of the epidural catheter under the following conditions: into glass or polyvinylchloride reservoirs containing ropivacaine 0.2% with sufentanil 1, 0.75 or 0.5 μg mL−1; and into polyvinylchloride reservoirs with ropivacaine 0.2% and sufentanil 1 μg mL−1 which were stored for 4 weeks at 8°C.

Results: The different solutions remained stable over the observation period of 96h. Using the same solutions, independent samples’ ANOVA showed no difference in the sufentanil concentrations between the glass and polyvinylchloride reservoirs, or between the polyvinylchloride reservoirs when stored for 4 weeks. Correlations between the concentrations at the different measurement times were extremely high for the reservoir (rmin = 0.98, rmax = 1.00) and the catheter end (rmin = 0.86, rmax = 1.00).

Conclusions: Sufentanil citrate at 0.5–1.0 μg mL−1 in an admixture of ropivacaine 0.2% for 5 days, which is the usual period for postoperative epidural analgesia, remains stable in a polyvinylchloride reservoir. There is no change in the drug concentration even if the reservoir is stored for 4 weeks at 8°C.

Background and objective: The study evaluated the manpower requirements in anaesthesia in Belgium until 2020. The basic intent was to estimate the need for anaesthesiologists in different hospitals because the number of medical students will be reduced to 700 in 2004 and to 600 in 2007 (numerus clausus), and the number of trainees in anaesthesia from 110 to 42 (best scenario) or to 21 (worst scenario). Simultaneous anaesthesia (more than one patient at the same time) is not allowed by our professional safety rules or by the Belgian Ministry of Public Health. The questions are: will we have enough anaesthesiologists in the next 20 years, and is there a need for nurses to administer anaesthesia? This professional title of nurse anaesthetist does not presently exist in Belgium.

Methods: Every registered anaesthesiologist in Belgium received a questionnaire about the manpower requirements in his or her institution expected over the next 20 years. The workload in the specialty was also considered.

Results: We received 154 replies from 186 different hospitals. The workload is definitely high: 10 h per day was devoted to clinical work and 4.6 h per week to administration. Belgium will need 51 anaesthesiologists each year after 2004, and 58 each year from 2010 to 2020.

Conclusions: Will anaesthesiologists accept their present high workload for the next 20 years? If not, the consequences will be serious. Three-quarters (75.4%) of the replies identified a need for more anaesthesiologists and considered that an anaesthesiologist supervising anaesthesia nurses for a number of patients simultaneously was a possible solution.

Background and objective: In this randomized, double-blind study, we aimed to investigate the effect of aminophylline on recovery from sevoflurane.

Methods: One-hundred ASA I–II patients scheduled for elective surgery were randomly divided into two groups receiving either NaCl 0.9% (Group 1, n = 50) or aminophylline 5 mg kg−1 (Group 2, n = 50). All patients were premedicated with atropine 0.01 mg kg−1 and midazolam 0.06 mg kg−1 intramuscularly. Anaesthesia was induced with propofol 2 mg kg−1 for muscle relaxation, and atracurium 0.5 mg kg−1 was maintained with sevoflurane 2% in 50% oxygen and nitrous oxide. Further atracurium (0.1 mg kg−1 was given when needed. Aminophylline or saline was given after sevoflurane was discontinued. Heart rate, mean arterial pressure, peripheral oxygen saturation, the duration of anaesthesia and recovery times (eye opening, verbal response, extubation and successful performance of arithmetical calculations) were recorded.

Results: There were no statistically significant differences in mean arterial pressure, peripheral oxygen saturation and anaesthesia time between the two groups. Heart rate increased significantly (P < 0.05) after aminophylline and was also higher than in the placebo group. Recovery times were significantly shorter (P < 0.001) in the patients receiving aminophylline.

Conclusions: Aminophylline speeded recovery after sevoflurane anaesthesia and it may have some advantage in anaesthesia practice for patients.

Background and objective: The aim of this prospective, randomized study was to compare the preparation and discharge times, the side-effects and patient satisfaction after gynaecological outpatient procedures performed using either spinal block or total intravenous anaesthesia with propofol and remifentanil.

Methods: With Ethics Committee approval and written informed consent, 40 healthy females scheduled for hysteroscopic ablation of endometrial neoplasm were randomly allocated to receive either a spinal block with bupivacaine 0.5% hyperbaric solution 10 mg (n = 20) or total intravenous anaesthesia with propofol and remifentanil (n = 20). Preparation and discharge times, as well as occurrence of untoward events and anaesthesiarelated costs, were recorded.

Results: The median (range) preparation time was 7 (7–10) min with general anaesthesia, and 11 (7–21) min with spinal block (P = 0.00005). No differences in discharge time from the postanaesthesia care unit and incidence of hypotension or bradycardia, or both, were reported between the two groups. Hospital discharge times were 156 (101–345) min after general anaesthesia and 296 (195–720) min after spinal anaesthesia (P = 0.0005). Acceptance of the anaesthesia technique was better after general (100%) than after spinal anaesthesia (75%) (P = 0.04). No differences in total costs were reported between spinal block (€155 (€117–€224)) and propofol-remifentanil general anaesthesia (€143 (€124–€203) (P = 0.125)).

Conclusions: Accurate titration of short-acting intravenous anaesthetic drugs such as propofol and remifentanil results in shorter preparation times and earlier home discharge after outpatient gynaecological procedures compared with spinal anaesthesia with hyperbaric bupivacaine 10 mg, with better patient acceptance and no increased costs.

The intubating laryngeal mask airway is a modification of the conventional laryngeal mask and is used as a tool for difficult intubation. It can be inserted without placing the head and neck in the Magill position and has been used successfully in cervical spine injuries. Reported is a case of successful insertion of the intubating laryngeal mask and subsequent intubation through it in a patient with ankylosing spondylitis with cervical involvement resulting in a fixed flexion deformity who underwent coronary artery bypass grafting.

Background and objective: Comparison of the effectiveness of tramadol with meperidine given intravenously to emergency patients with suspected renal colic.

Methods: A double-blind, randomized clinical trial was performed in the Emergency Department of a tertiary-care university hospital. Consecutive patients with suspected renal colic (n =47) were randomized to receive intravenously an initial dose of tramadol 50 mg (n = 23) or meperidine 50 mg (n = 24). After 30 min, additional doses of meperidine 50 mg were given intravenously as a rescue medication in an open fashion. Pain relief was assessed using a 10 cm visual analogue scale, the primary outcomes being pain relief at 15 and 30 min after the analgesics. Secondary outcomes were the frequency of rescue meperidine use and the development of side-effects.

Results: Visual analogue scale pain scores after 15 and 30 min decreased in both tramadol and meperidine groups (P < 0.05). However, pain relief was better in the meperidine group at the 15 and 30 min evaluations (P < 0.05). Only 11 patients (48%), initially receiving meperidine, needed more meperidine compared with 16 patients (67%) initially receiving tramadol. Both drugs were well tolerated with no adverse effects occurring in either group.

Conclusions: Meperidine 50 mg was superior to tramadol 50 mg for acute pain relief in patients with suspected renal colic when given intravenously. Because many patients in both groups received supplemental meperidine and the response to tramadol alone cannot be predicted, clinicians may want to choose higher doses of meperidine alone or other alternative combinations.