LABOR EPIDURAL ANALGESIA WITH AMBULATION: SELF-ADMINISTERED VERSUS NURSE-ADMINISTERED INTRAVENOUS NALOXONE FOR EPIDURAL SUFENTANIL-INDUCED PRURITUS
S. Cohen, H. Denenberg, S. Alexander, J. Chhokra, R. Smith, A. Grosu, V. Bokhari, F. Burley, E. Trnovski, Berman, Anesthesia, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ

AIM OF INVESTIGATION: We compared patient (pt) vs. staffadministered IV naloxone (N) for labor epidural (E) induced pruritis, to determine which method enhanced pt control and decreased the need for staff intervention.

METHODS: 300 consenting parturients (IRB approved) who requested E analgesia with ambulation received Epi-PCA infusion of ropivacaine 0.04% + sufentanil 1 mcg/ml + epinephrine 2mcg/ml. Group I (n=150): pt-administered IV N 8 mcg/ml, pt-controlled dose (0.04mg) 5ml, lockout 5min (Abbott PCA pump). Group II (n=150): received IV N 0.04 mg from our staff every 5 min prn. Pts were evaluated hourly. Mean SD; p<0.05 was significant.

RESULTS: Satisfaction with the N treatment was 8.71.7 & 8.22.1, 99 pts (66%) and 90 pts (60%) ambulated for 44.845.2 and 53.266.7, C/S rate was 18 (12%) & 20 (13%) and neonates with apgar score <7 at 5 min was 1 & 0 for GI & II, respectively. Total Epi-PCA infusion per duration 12.75.0, 12.65.7 ml/hr, PCA attempts/duration 1.61.6, 1.41.7, # of pts with pruritis 134 (89%), 124 (83%), # of pts requiring N treatment 132 (88%), 46 (31%) and total N required 0.20.3, 0.08 0.2, p<0.00001, for GI & II, respectively.

CONCLUSION: Pt-administered IV N enhanced pt control of treatment of E sufentanil-induced itching and decreased the need for staff intervention. The greater amount of N used by the self-administered group is strongly suggestive of the need to treat itching in pts. Self-administering N makes our pts more aware of the need to treat itching that otherwise might go untreated.

ACKNOWLEDGEMENTS: Dept. financial support

NALBUPHINE ANTAGONIZES RESPIRATORY DEPRESSION BUT DECREASES ANALGESIA IN PATIENTS GIVEN SUFENTANIL INFUSION INTRAOPERATIVELY
C. Kolbitsch, I.H. Benzer, A. Luger, T.J., Anaesthesia, University of Innsbruck, A-6020 Innsbruck, Austria

AIM OF INVESTIGATION: The opioid-agonist-antagonist nalbuphine is known to antagonize morphine or fentanyl (1) (2) induced respiratory depression while maintaining analgesia. Thus, the present study aimed to evaluate the effect of nalbuphine on respiratory depression and analgesia in patients given sufentanil infusion intraoperatively.

METHODS: Following approval of the local University Ethics Committee and written informed consent six patients undergoing major spinal surgery received sufentanil bolus (2 mcg/ kg) followed by infusion (1 mcg/ kg/ h) intraoperatively. Postoperative sufentanil infusion (0.5 mcg/ kg/ h) was stopped after a period of stabilisation and occlusive pressure (P-0.1 value), spontaneous tidal volume (Vt) and visual analog scale (VAS) value were measured. Then a bolus of nalbuphine (0.05 mcg/ kg) was given twice (B1 and B2). After each bolus measurements of spontaneous ventilation (P-0.1 value, Vt) and analgesia (VAS value) were repeated.

RESULTS: The first (B1) and even more pronounced the second (B2) bolus of nalbuphine increased P-0.1 value (baseline: 0.63 0.17 vs. B1: 2.22 0.17 a vs. B2: 3.1 0.35 a, b). Similarly, the tidal volume (Vt) increased (baseline: 180 37 mL vs. B1: 528 34 mL a vs. B2: 695 33 mL a, b). Analgesia, however decreased with each bolus of nalbuphine (baseline: 0 vs. B1: 1 0.13 a vs. B2: 3.1 0.35 a, b). a significant to baseline (p < 0.05); b significant to nalbuphine (B1) (p < 0.05); Values are given as mean SEM.

CONCLUSIONS: Nalbuphine antagonizes sufentanil caused respiratory depression (e.g. increased P0.1 value and Vt) but decreases analgesia.

REFERENCES: (1) Bailey PL et al.; Anesth Analg 1987; 66:1109-14. (2) Pugh GC et al.; Br J Anesth 1989; 62:601-9.

COMPARISON OF DIPYRONE WITH PENTAZOCINE FOR POSTOPERATIVE PAIN RELIEF FOLLOWING GYNAECOLOGICAL SURGERY.
O. Erhenede, C.O. Oriyomi, O.O. Kushimo, ANAESTHESIA, LAGOS UNIVERSITY TEACHING HOSPITAL, Lagos, Nigeria

Aim of Investigation: To compare the analgesic efficacy of intra-muscular Dipyrone with Pentazocine for postoperative pain relief following Gynaecological surgery.

Methods: One hundred female patients undergoing elective gynaecological surgery were randomized to receive a single postoperative dose of either 2.5g Dipyrone or 30mg Pentazocine by the intra-muscular route. All patients received a general anaesthetic relaxant technique. In the immediate postoperative period when the patient complained of moderate to severe pain, the treatment dose was given. Assessment of pain was at 30 minutes, 1 hour, then hourly for 6 hours using: 1) a four point verbal rating scale (VRS). 2) a 10cm visual analogue scale (VAS) and 3) A 5 point pain relief scale. Adverse events and satisfaction were also noted.

Results: There was no difference in pain intensity between the two groups. Local and systemic tolerance with both drugs were good.

Conclusion: The analgesic efficacy of Dipyrone was comparable with that of Pentazocine. Its routine use is recommended for moderate to severe postoperative gynaecological pain.

POSTOPERATIVE ANALGESIA WITH TRAMADOL AND DIPYRONE
U.M. Stamer. F. Hoethker, Lehnen, K., Department of Anesthesiology and Intensive Care Medicine, University of Bonn, Bonn, Germany

Aim of Investigation: Tramadol (T) and dipyrone (D) are widely used for continuous intravenous postoperative analgesia in Germany. There are no reports of using this combination via PCA (patient-controlled analgesia) up to now. A comparison of this analgesic combination either administered as infusion or PCA seems to be appropriate.

Methods: After approval of the local ethics committee and written informed consent patients undergoing major abdominal surgery were included into the study. After a loading dose given before the end of surgery and an individual titration in the recovery room patients were randomized to one of two study groups. 100 patients were treated with a combination of tramadol and dipyrone i.v. applicated by PCA (bolus dose T 20 mg + D 200 mg) and 100 patients were treated with this combination by continuous infusion which could be adjusted to patients' individual demands (10-100 mg T + 100-1000 mg D/h). This study compares analgesia and analgesic consumption of the two study groups for 48 hours. Furthermore, the number of interventions which were necessary to adjust the setting of the infusion devices were recorded.

Results: Cumulative analgesic consumption was significantly higher in the infusion group (24 h: 630263 mg T) compared to the PCA group (473269 mg T; p<0.001). Pain scores did not differ between the two treatment groups. In the infusion group 2-6 interventions were necessary to adjust the infusion rate to individual needs compared to 0-1 interventions in the PCA group.

Conclusions: Patients of both treatment groups experienced adequate analgesia. However, PCA met patients' individual demands much better and could reduce interventions by the staff necessary to adjust therapy.

POSTOPERATIVE PAIN CONTROL WITH BUPRENORPHINE COMPARED TO NALBUPHINE THROUGH CONTINUOUS EPIDURAL INFUSION IN POSTOPERATED PATIENTS WITH TOTAL HIP ARTHROPLASTY
M.A. Genis, A. Castellanos, I. Vazquez, A. Antonio, P. Guevara, Enseanza, Centro Medico Nacional, D.F., Mexico , ² Anesthesiology, Hospital Ortopedia IMSS, D.F., Mexico

AIM OF INVESTIGATION: To demonstrate that the analgesia obtained with Buprenorphine is higher than the one with Nalbuphine through continuos epidural infusion.

METHODS: This was a doubleblind, randomized groups study to compare Buprernorphine 6 mcg/Kg weight and Nalbuphine 5 mg diluted in physiological solution 49 ml in an infusor singleday 2 ml/hr and connected L2 L3 in the epidural space.

RESULTS: 87 patients were studied. In Group I (Buprernorphine) 44 patients with an average weight of 68.70 kg, age 59.63 years average. Pain relief according to the Visual Analog Scale was of 6 hours with an VAS of 2.47 at 12 hours VAS 1.89, at 18 hours, VAS 1.01, and at 24 hours, VAS 0.23 The secondary effects were more noticeable in this group, such as nausea, vomiting, drowsiness, and arterial hypotension. In Group II (Nalbuphine) 43 patients with an average weight of 65.00 kg, age 58.02 years average were studied. Pain control was at 6 hours VAS 4.98, at 12 hours VAS 3.16, at 18 Hours VAS 2.41 and at 24 hours VAS 1.60 The control of pain was more significant, statistical difference with P<0.05 compared to Nalbuphine. Analgesia with buprenorphine was better than Nalbuphine at 6, 12, 18 and 24 hours.

CONCLUSIONS: The sophisticated goal of control postoperatory pain is to achive success. And Whit the use of Buprernophine by continual epidural infusion, the relief of pain is excellent

ACKNOWLEDGMENTS: Supported by Aventis Pharma, Baxter,Schering-Plough Company and Juan Garcia G.

PATIENT-CONTROLLED ANALGESIA IN THE CONTROL OF ISCHEMIC PAIN:A RETROSPECTIVE STUDY
M.P. Pavan. I.P. Ashmawi, H.A. Lobo, Pain Unit, Dept. of Anesthesiology, Hospital das Clnicas da Faculdade de Medicina da Universidade de So Paulo, São Paulo, Brazil

Aim of Investigation:To describe the analgesic approaches performed in our service to control ischemic pain and to evaluate the analgesic efficacy and patient satisfaction related to the most performed technique.

Methods:After approval by the Ethical Committee of our hospital,data documentation of 126 patients assisted between February 1999-February 2001 were reviewed.Analgesic efficacy was evaluated according to the pain intensity referred by a verbal numeric scale 0-10.Patient satisfaction was evaluated according to a 0-3 scale.

Results:Occlusive arterial disease prevailed as cause of pain (67%).All the patients were already taking analgesics prescribed by the surgeons(second-step of the WHO analgesic ladder)without achieving pain control when the pain unit was requested.26% received IV-patient controlled analgesia(PCA)with morphine,27% epidural PCA (PCEA) with bupivacaine+fentanyl,10% both IV-PCA or PCEA,20% SC morphine,10% oral morphine and 7% oral slow release oxycodone.79% submitted to IV-PCA and 84% to PCEA were highly satisfied.76,5% receiving PCEA reported pain scores between 0-3,and only 28% in the IV-PCA group.

Conclusions:Administration of strong opioids were made mainly by high technology devices(53%).Best control of ischemic pain and higher patient satisfaction were achieved in the PCEA group.The cooperation of the vascular surgery team and the pain unit allowed the WHO ladder to be followed.

COMPARISON OF THE ANALGESIC EFFICACY AND SAFETY OF TRAMADOL AND MORPHINE IN POSTOPERATIVE PAIN IN CHILDREN
W. Habre, Z. Barcot, A. Van de Velde, R. Nijholt4, D. Gremmels, Childrens Hospital, Geneva, Switzerland , Childrens Hospital, Zagreb, Croatia , Vrije Universiteit, Brussels, Belgium , Academisch Ziekenhuis, Groningen, Netherlands , ⁵ Grnenthal GmbH, Aachen, Germany

Aim of Investigation: To evaluate the analgesic efficacy and safety of postoperative i.v. administration of tramadol (T) or morphine (M) in children.

Methods: 150 children (2-8 years) undergoing abdominal or urological surgery were involved in a randomised, multicentre, double-blind clinical trial. Children received T or M at a dose of 1-2 mg/kg or 0.1-0.2 mg/kg, respectively. Objective pain scale (OPS) was used to assess pain and T or M was supplemented within the predefined limits. Vital signs, OPS and sedation level were recorded up to 6 hours postoperatively and adverse events up to 24 hours.

Results: The groups were comparable with regard to age, surgery and anesthesia management. The total required dose administered to children in order to achieve adequate analgesia (response: OPS<4) after one hour was 1.23 0.28 mg/kg (T) and 0.11 0.02 mg/kg (M) respectively. Overall, 7.7% T and 2.2% M of therapies were rated as "dissatisfactory" by the investigators. Sedation scores were lower in group T than M after one hour (median (IQR): 2.0 (2-3) vs 3.0 (2-3) respectively, p=0.007). Incidence of postoperative adverse events was comparable between groups (32.7% in group T vs 34.8% group M, p=0.8). Incidence of nausea (5.8% vs 6.5%) and vomiting (28.8% vs 26.1%) was comparable between T and M.

Conclusions: Tramadol and morphine both show adequate analgesic effects with a comparable side effect profile. The dose of T necessary to provide comparable analgesic efficacy to M appears to be approximately 11:1 in children.

Acknowledgments: The study was supported by Grnenthal GmbH, Aachen, Germany.

EFFECTS ON POSTCESAREAN ANALGEISA AND OXYGEN SARTURATION BY NEURAXIAL SINGLE MORPHINE ADMINISTRATION
R. Masuda. Z. Yamaguchi, M. Inoue, T., Anesthesiology, Chiba-Hokusoh Hospita, Nippon Medical School, Chiba, Japan

AIM OF INVESTIGATION: Postoperative anticoagulant therapy may limit the management of neuraxial catheters. We assessed whether single dose morphine injected via the intrathecal or epidural route sufficiently maintained postcesarean analgesia and satisfactory respiratory indicators including oxygen saturation.

METHODS: After IRB approval, 72 parturients who received neuraxial anesthesia during cesarean section participated in this study. A single dose of morphine was preoperatively administered either intrathecally (0.1mg, IT1 group, n=18; 0.2mg, IT2 group, n=18) or epidurally (3mg, EP1 group, n=18; 5mg EP2 group, n=18) for postcesarean analgesia. Postoperative analgesia (VAS), score on the sedation scale (OAA/S), PONV, pruritus, respiratory rates and SpO2 were assessed at every 6 hour for 48 hours following morphine administration. Oxygen supply prepared when desaturation (SpO2 <95) or hypoventilation (RR<10 per min) was observed. Continuous readings of SpO2 were also recorded for 24 hours and analyzed. Results analyzed by ANOVA and t-test were considered significant at the P<0.05 level.

RESULTS: Groups were demographically similar. Analgesia within the first 24 hours was sufficient in the IT1, IT2, and EP2 groups. None of the patients required supplemental oxygen and neither low respiratory rate (<12 breath per minute) nor desaturation (<95) were evidenced by observerfs assessment. Transient SpO2 falls during sleep were recorded in the IT2, EP1, and EP2 groups. Desaturation, PONV and pruritus were not recorded in the IT1 group.

CONCLUSIONS: A single dose of 0.1mg morphine administered intrathecally maintained postcesarean analgesia sufficiently to minimize the adverse effects of neuraxial morphine administration.

THE ANALGESIC EFFECT OF TRAMADOL AFTER IV INJECTION IN EXTENSIVE AND POOR METABOLISERS OF SPARTEINE
T. Enggaard,^, S.H. Brosen, K. Andersen, A.H. Poulsen, L.Clinical Pharmacology, Institute of Public Health, University of Southern Denmark, 5000-DK Odense, Denmark

Background: Tramadol analgesia seems to depend on a monoaminergic effect of tramadol itself and an opioid effect of its metabolite (+)-M1, which is formed by O-demethylation of tramadol via CYP2D6.

Objective: The aim of this study was to determine the impact of (+)-M1 on the acute analgesic effect of tramadol.

Methods: The effect of an intravenous injection of 100 mg tramadol on experimental pain was studied 15-90 minutes after dosing in 10 extensive metabolizers of sparteine with CYP2D6 and 10 poor metabolizers without CYP2D6 in two parallel, randomized, double-blind, placebo-controlled cross-over trials.

Results: In extensive metabolizers, tramadol reduced discomfort experienced during the cold pressor test (p = 0.002) and the increase in pain detection and tolerance thresholds to electrical sural nerve stimulation correlated with serum concentrations of (+)-M1 (rs = 0.70, p < 0.05 and rs = 0.77, p < 0.02). In poor metabolizers, only pain tolerance thresholds to sural nerve stimulation were increased (p = 0.04).

Conclusion: The opioid effect of (+)-M1 appears to contribute to the acute analgesic effect of tramadol, but tramadol analgesia seems also to be provided by the monoaminergic effect of tramadol itself.

PAIN MANAGEMENT IN NEONATES AT RISK FOR NEUROLOGIC IMPAIRMENT
B. Stevens, S. Gibbins, J. Beyenne, L. Breau, C. Camfield, A. Finley, L. Franck, A. Howlett, K. O'Brien, A. Ohlsson, University of Toronto, Toronto, ON, Canada , ²Hospital for Sick Children, Toronto, ON, Canada , Dalhousie University, Halifax, NS, Canada , IWK Health Centre, Halifax, NS, Canada , Sunnybrook & Womens Health Sciences Center, Toronto, ON, Canada , Mount Sinai Hospital, Toronto, ON, Canada , ⁷ King's College London, London, United Kingdom

Aim of Investigation: To compare the(a)nature and prevalence of painful procedures and (b)analgesics administered for neonates at varying levels of risk for neurological impairment.

Methods: In a retrospective cohort study, 194 neonates from two NICU's were prognostically stratified by high (Cohort A; n=67), moderate (Cohort B, n=59) and low (Cohort C, n=68) risk for neurologic impairment. Data were collected on painful procedures and analgesics administered from medical records and analyzed using chi square and ANOVA.

Results: Cohort A had the lowest Apgar scores (F=31.04,p<0.001), the highest severity of illness (SNAP-IIJ F=34.17, p<0.001) and the most painful procedures (F=4.79, p<0.009). There were no differences in systemic opioids (p<0.13), bolus opioids (p<0.25), sedatives (p<0.84) or neuromuscular agents (p<0.14)among cohorts. All groups had >10 painful procedures/day during the first 3 days of life.

Conclusions: Infants at the greatest risk for neurologic impairment had the largest number of painful procedures but no differences existed in the analgesia administered. Severity of illness and risk status did not influence the type or amount of analgesic administration. Further research is required on factors impacting pain management in infants at risk for neurologic impairment.

Acknowledgements; Canadian Institutes for Health Research, Grant # MOP-37884.

THE EFFECT OF LOW-DOSE REMIFENTANIL AND NITROUS OXIDE (N2O) ON PAIN TOLERANCE IN CONSCIOUS HUMAN VOLUNTEERS
T.J. Luger, I.H. Benzer, A. Kolbitsch, C., Dept of Anaesthesia and Intensive Care Medicine, Univ of Innsbruck, Innsbruck, Austria

AIM OF INVESTIGATION: To evaluate the effect of low-dose remifentanil and nitrous oxide on pain tolerance in humans.

METHODS: After obtaining the approval of the local University Ethics Committee and written informed consent, a mechanical pressure-pain tolerance model was used to investigate the influence of nitrous oxide (20%, 35% and 50% end-tidal concentration (FeN2O)) and of remifentanil (0.025, 0.05, 0.075 and 0.1 mcg/ kg/ min) on pain tolerance (% of maximum possible effect; %MPE) of conscious volunteers (n=11).

RESULTS: In contrast to the higher doses tested, neither drug influenced pain tolerance at low-dose (e.g., remifentanil 0.025 mcg/ kg/ min, 20% FeN2O). A 50% increase of pain tolerance was found at interpolated 45% FeN2O and at 0.05 mcg/ kg/ min remifentanil.

CONCLUSIONS: Remifentanil at a dose of 0.05 mcg/ kg/ min increases pain tolerance by 50% MPE and an approximate doubling of the dose (0.1 mcg/ kg/ min) is necessary for a further significant increase in pain tolerance. Nitrous oxide, by contrast, comparably increased pain tolerance (e.g., 50%MPE) only at a higher dose (e.g. interpolated 45% FeN2O)

10th World Congress on Pain, List of topics

10th World Congress on Pain. International Association for the Study of Pain, San Diego, California, USA August 17-22, 2002