Pain, 48 (1992) 1.57-158 0 1992 Elsevier Science
157 Publishers
B.V. All rights reserved
0304-3959/92/$05.00
PAIN 01935
Does opiate premeditation influence postoperative A prospective study Ivan E. Kiss and Mathias
analgesia?
Kilian
Klinik fiir Anaesfhesir, Intensil~medizin und Schmerztherapie, Alfried Krupp Krankenhaus, 4300 Essen (Germany) (Received
22 April 1991; accepted
17 June 1991)
The influence of opiate premeditation on analgesic requirements postoperatively was investigated. Out of 98 patients with a lumbar disc prolapse 50 were premeditated with flunitrazepam orally, 48 with pethidine and triflupromazine intramuscularly. The operations were performed under inhalational anaesthesia. The average time up to the first demand for an analgesic was longer following opiate premeditation (351 vs. 219 min). Only 45.8% of the patients treated with opiates demanded analgesics postoperatively, compared to 80.0% of those who had a benzodiazepine premeditation (P < 0.01). These clinical data confirm the experimental evidence that pretreatment with opiates diminishes the sustained hyperexcitation of the central nervous system caused by peripheral lesions. Summary
Key words: Opiate; Premeditation;
Hemilaminectomy;
Introduction
The clinical impression that opiate premeditation is followed by reduced narcotic requirements intraoperatively was confirmed by a retrospective study of more than 900 patients; McQuay et al. (1988) found that opiate premeditation and/or regional anaesthesia lengthens the postoperative pain-free period. The aim of this study was to determine whether there is any difference in the frequency of postoperative analgesic demand and in the length of the pain-free period in patients premeditated with benzodiazepines or opiates.
Methods Ninety-eight patients (ASA I-11) in the Department of Neurosurgery of the University of Freiburg were examined before and following lumbar disc surgery. Patients taking long-term analgesic medication and those being treated with psychotropic drugs were excluded from the study. All patients received diclofenac postoperatively in order to reduce oedema formation.
Postoperative
analgesia
Preoperatively, the duration of complaints and the lateralisation of pain were explored. Pain intensity was measured by a visual analogue scale (VAS l-100). The State-Trait Anxiety Inventory (STAI Xl) was used to determine preoperative anxiety. As premeditation the first 50 patients received 2.0 mg flunitrazepam orally 60-90 min before the induction of anaesthesia (group 1). The 48 patients in group 2 were premeditated with 20 mg triflupromazine i.m. and 50 mg pethidine i.m. Group demographics did not differ. The anaesthetic procedure was the same for all patients. Following precurarisation and 2 pg/kg body weight fentanyl, anaesthesia was induced with thiopentone. Succinylcholine (1.5 mg/kg body weight) was given to facilitate tracheal intubation. Anaesthesia was maintained with nitrous oxide (NO* 0.4) and a volatile anaesthetic (isoflurane in 70, halothane in 22, and enflurane in 6 patients). The operation was carried out in the prone position. The operative procedure consisted of a partial hemilaminectomy and the microsurgical removal of the prolapsed disc. Postoperatively, the frequency of demand for analgesics, the time elapsed between completion of the operation and the first dose, and the total dose during the first 3 days were documented. The pain was treated with 100 mg tramadol given orally as demanded. In case of postoperative nausea or vomiting the drug was given intravenously (1 patient in each group). The chi-square test and the Wilcoxon test for random samples were used for statistical analysis. P < 0.05 was considered significant.
Results Correspondence CO: Ivan Emil Kiss, Klinik fur Anaesthesie, Intensivmedizin und Schmerztherapie, Alfried Krupp Krankenhaus, Alfried Krupp Str. 21, 4300 Essen, Germany.
Of the 48 patients premeditated with pethidine and triflupromazine, 22 (45.8%) required postoperative
TABLE I Postoperative analgesics
Number of patients Men Women Age (years) Premedi~tion Flunitrazepam Pethidine + triflupromazine
Yes
No
62 41 (59.4%) 21 (72.4%) 43.65 11.5
36 28 (40.6%) 8 (27.6%) 46.5+ll.l
40 (80.0%) 22 (45.8%)
10 (20.0% ) 26 (54.2%)
analgesic medication; 40 out of the 50 patients premedicated with flunitrazepam (80%) demanded postoperative analgesics (P < 0.01) (Table I). In the group receiving opiate premeditation the average time to the first demand for analgesics was longer (351 vs. 219 min) and the total dose in the first 48 h postoperatively lower (227 vs. 284 mg tramadol) than in the other group. More women than men demanded analgesics (Table I). The men required a higher dose of tramadol (on average 278 vs. 236 mg/48 h). Age, duration of preoperative complaints, preoperative anxiety, intensity of preoperative pain, Iateralisation of pain, and the choice of volatile anaesthetics did not have any influence on the postoperative analgesic demand. In patients of group 1 postoperative pain intensity was measured before the first analgesic medication; the average score of the VAS was 65.
Discussion There are no concrete data in the literature concerning the frequency and intensity of postoperative pain following partial hemilaminectomy. The pain found in this study was not particularly severe. The average VAS score showed values of ‘middle’ intensity. Tramadol, a weak opioid, provided adequate pain relief in all cases. The most interesting result in this study is that opiate premeditation significantly reduces postoperative analgesic requirements. Only 45.8% of these patients demanded postoperative analgesics compared to 80% in the benzodiazepine group. Furthermore they required the first dose later in the postoperative period and also needed lower total doses. Two points regarding the methods used in the study might be subject to criticism. First, the lack of randomization was due to organizational problems. Nevertheless we are confident that the data are of clinical relevance. The second target of criticism might be that fentanyl was administered routinely prior to intubation. This measure is usually taken to reduce hemodynamic responses to laryngoscopy and intubation. As all patients received fentanyl, the results obtained do not
lose their validity. The question, however, whether the differences in analgesic requirements between the 2 groups could have been more pronounced if the patients had not been given fentanyl treatment is open to speculation, The question arises how small doses of opiates given preoperatively have an analgesic effect in the postoperative period that lasts longer than the alleged clinical efficacy. During the last few years we gained new insight into the pathophysiology of acute pain (Woolf 1989). According to animal experimental data, nociceptive impulses that travel along the C-fibres induce a long-lasting hyperexcitable state in the centra1 nervous system (Woolf 1983; Cook et al. 1987). IIigh doses of opiates are required to suppress this state, however, pretreatment with small doses of opiates can reduce its extent (Woolf et al. 1986a,b). The results of this study confirm that opiate premeditation diminishes the sustained hyperexcitabili~ of the central nervous system caused by intraoperative stimuli. For clinical practice that means that pain arising postoperatively can be significantly reduced by opiate premeditation (Wall 1988). Opiate premeditation is generally becoming more and more unpopular. The main reasons for this trend are the fear of possible opiate side effects and the ease of administration of oral benzodiazepines. At present preoperative pain is the main indication for opiate premeditation. The results of this study suggest that there are more aspects to be considered when deciding on whether to give opiates before surgery. The fact that the analgesic effect is sustained into the early postoperative period gives the patient more comfort during transfer back to the bed, transport to the ward, up to the time until the first postoperative analgesic is administered. In conclusion, premeditation with opiates in comparison with benzodiazepines prolongs the pain-free period and significantly decreases the frequency of demand for analgesics postoperatively. References Cook, A.J., Wootf, Cf., Wail, P.D. and ~cMahon, S.B., Dynamic receptive field plasticity in rat spinal cord dorsal horn following C-primary afferent inputs, Nature, 325 (1987) 151-153. McQuay, I-LJ., Carroll, D. and Moore, R.A., Postoperative orthopaedic pain - the effect of opiate premeditation and local anaesthetic blocks, Pain, 33 (1988) 291-295. Wail, P.D., The prevention of postoperative pain, Pain, 33 (1988) 289-290. Woolf, C.J., Evidence for a central component of post-injury pain hypersensitivity, Nature, 306 (1983) 686-688. Woolf, C.J., Recent advances in the pathophysiology of acute pain, Br. J. Anaesth., 63 (1989) 139-146. Woolf, C.J. and Wall, P.D., Morphine-sensitive and morphine-insensitive actions of C-fibre input on the rat spinal cord, Neurosci. Lett., 64 (1986a) 221-22.5. Woolf, C.J. and Walt, P.D., A dissociation between the analgesic and antinociceptive effects of morphine, Neurosci. Lett., 64 (1986b) 238.
157 Publishers
B.V. All rights reserved
0304-3959/92/$05.00
PAIN 01935
Does opiate premeditation influence postoperative A prospective study Ivan E. Kiss and Mathias
analgesia?
Kilian
Klinik fiir Anaesfhesir, Intensil~medizin und Schmerztherapie, Alfried Krupp Krankenhaus, 4300 Essen (Germany) (Received
22 April 1991; accepted
17 June 1991)
The influence of opiate premeditation on analgesic requirements postoperatively was investigated. Out of 98 patients with a lumbar disc prolapse 50 were premeditated with flunitrazepam orally, 48 with pethidine and triflupromazine intramuscularly. The operations were performed under inhalational anaesthesia. The average time up to the first demand for an analgesic was longer following opiate premeditation (351 vs. 219 min). Only 45.8% of the patients treated with opiates demanded analgesics postoperatively, compared to 80.0% of those who had a benzodiazepine premeditation (P < 0.01). These clinical data confirm the experimental evidence that pretreatment with opiates diminishes the sustained hyperexcitation of the central nervous system caused by peripheral lesions. Summary
Key words: Opiate; Premeditation;
Hemilaminectomy;
Introduction
The clinical impression that opiate premeditation is followed by reduced narcotic requirements intraoperatively was confirmed by a retrospective study of more than 900 patients; McQuay et al. (1988) found that opiate premeditation and/or regional anaesthesia lengthens the postoperative pain-free period. The aim of this study was to determine whether there is any difference in the frequency of postoperative analgesic demand and in the length of the pain-free period in patients premeditated with benzodiazepines or opiates.
Methods Ninety-eight patients (ASA I-11) in the Department of Neurosurgery of the University of Freiburg were examined before and following lumbar disc surgery. Patients taking long-term analgesic medication and those being treated with psychotropic drugs were excluded from the study. All patients received diclofenac postoperatively in order to reduce oedema formation.
Postoperative
analgesia
Preoperatively, the duration of complaints and the lateralisation of pain were explored. Pain intensity was measured by a visual analogue scale (VAS l-100). The State-Trait Anxiety Inventory (STAI Xl) was used to determine preoperative anxiety. As premeditation the first 50 patients received 2.0 mg flunitrazepam orally 60-90 min before the induction of anaesthesia (group 1). The 48 patients in group 2 were premeditated with 20 mg triflupromazine i.m. and 50 mg pethidine i.m. Group demographics did not differ. The anaesthetic procedure was the same for all patients. Following precurarisation and 2 pg/kg body weight fentanyl, anaesthesia was induced with thiopentone. Succinylcholine (1.5 mg/kg body weight) was given to facilitate tracheal intubation. Anaesthesia was maintained with nitrous oxide (NO* 0.4) and a volatile anaesthetic (isoflurane in 70, halothane in 22, and enflurane in 6 patients). The operation was carried out in the prone position. The operative procedure consisted of a partial hemilaminectomy and the microsurgical removal of the prolapsed disc. Postoperatively, the frequency of demand for analgesics, the time elapsed between completion of the operation and the first dose, and the total dose during the first 3 days were documented. The pain was treated with 100 mg tramadol given orally as demanded. In case of postoperative nausea or vomiting the drug was given intravenously (1 patient in each group). The chi-square test and the Wilcoxon test for random samples were used for statistical analysis. P < 0.05 was considered significant.
Results Correspondence CO: Ivan Emil Kiss, Klinik fur Anaesthesie, Intensivmedizin und Schmerztherapie, Alfried Krupp Krankenhaus, Alfried Krupp Str. 21, 4300 Essen, Germany.
Of the 48 patients premeditated with pethidine and triflupromazine, 22 (45.8%) required postoperative
TABLE I Postoperative analgesics
Number of patients Men Women Age (years) Premedi~tion Flunitrazepam Pethidine + triflupromazine
Yes
No
62 41 (59.4%) 21 (72.4%) 43.65 11.5
36 28 (40.6%) 8 (27.6%) 46.5+ll.l
40 (80.0%) 22 (45.8%)
10 (20.0% ) 26 (54.2%)
analgesic medication; 40 out of the 50 patients premedicated with flunitrazepam (80%) demanded postoperative analgesics (P < 0.01) (Table I). In the group receiving opiate premeditation the average time to the first demand for analgesics was longer (351 vs. 219 min) and the total dose in the first 48 h postoperatively lower (227 vs. 284 mg tramadol) than in the other group. More women than men demanded analgesics (Table I). The men required a higher dose of tramadol (on average 278 vs. 236 mg/48 h). Age, duration of preoperative complaints, preoperative anxiety, intensity of preoperative pain, Iateralisation of pain, and the choice of volatile anaesthetics did not have any influence on the postoperative analgesic demand. In patients of group 1 postoperative pain intensity was measured before the first analgesic medication; the average score of the VAS was 65.
Discussion There are no concrete data in the literature concerning the frequency and intensity of postoperative pain following partial hemilaminectomy. The pain found in this study was not particularly severe. The average VAS score showed values of ‘middle’ intensity. Tramadol, a weak opioid, provided adequate pain relief in all cases. The most interesting result in this study is that opiate premeditation significantly reduces postoperative analgesic requirements. Only 45.8% of these patients demanded postoperative analgesics compared to 80% in the benzodiazepine group. Furthermore they required the first dose later in the postoperative period and also needed lower total doses. Two points regarding the methods used in the study might be subject to criticism. First, the lack of randomization was due to organizational problems. Nevertheless we are confident that the data are of clinical relevance. The second target of criticism might be that fentanyl was administered routinely prior to intubation. This measure is usually taken to reduce hemodynamic responses to laryngoscopy and intubation. As all patients received fentanyl, the results obtained do not
lose their validity. The question, however, whether the differences in analgesic requirements between the 2 groups could have been more pronounced if the patients had not been given fentanyl treatment is open to speculation, The question arises how small doses of opiates given preoperatively have an analgesic effect in the postoperative period that lasts longer than the alleged clinical efficacy. During the last few years we gained new insight into the pathophysiology of acute pain (Woolf 1989). According to animal experimental data, nociceptive impulses that travel along the C-fibres induce a long-lasting hyperexcitable state in the centra1 nervous system (Woolf 1983; Cook et al. 1987). IIigh doses of opiates are required to suppress this state, however, pretreatment with small doses of opiates can reduce its extent (Woolf et al. 1986a,b). The results of this study confirm that opiate premeditation diminishes the sustained hyperexcitabili~ of the central nervous system caused by intraoperative stimuli. For clinical practice that means that pain arising postoperatively can be significantly reduced by opiate premeditation (Wall 1988). Opiate premeditation is generally becoming more and more unpopular. The main reasons for this trend are the fear of possible opiate side effects and the ease of administration of oral benzodiazepines. At present preoperative pain is the main indication for opiate premeditation. The results of this study suggest that there are more aspects to be considered when deciding on whether to give opiates before surgery. The fact that the analgesic effect is sustained into the early postoperative period gives the patient more comfort during transfer back to the bed, transport to the ward, up to the time until the first postoperative analgesic is administered. In conclusion, premeditation with opiates in comparison with benzodiazepines prolongs the pain-free period and significantly decreases the frequency of demand for analgesics postoperatively. References Cook, A.J., Wootf, Cf., Wail, P.D. and ~cMahon, S.B., Dynamic receptive field plasticity in rat spinal cord dorsal horn following C-primary afferent inputs, Nature, 325 (1987) 151-153. McQuay, I-LJ., Carroll, D. and Moore, R.A., Postoperative orthopaedic pain - the effect of opiate premeditation and local anaesthetic blocks, Pain, 33 (1988) 291-295. Wail, P.D., The prevention of postoperative pain, Pain, 33 (1988) 289-290. Woolf, C.J., Evidence for a central component of post-injury pain hypersensitivity, Nature, 306 (1983) 686-688. Woolf, C.J., Recent advances in the pathophysiology of acute pain, Br. J. Anaesth., 63 (1989) 139-146. Woolf, C.J. and Wall, P.D., Morphine-sensitive and morphine-insensitive actions of C-fibre input on the rat spinal cord, Neurosci. Lett., 64 (1986a) 221-22.5. Woolf, C.J. and Walt, P.D., A dissociation between the analgesic and antinociceptive effects of morphine, Neurosci. Lett., 64 (1986b) 238.
