Forum
281
Anaesthesia, 1979, Volume 34, pages 281-283
Postoperative analgesia using papaveretum and orphenadrine. A preliminary trial
E.N.S. Fry, MB, ChB, FFARCS, Consultant Anaesthetist, North Tees General Hospital, Hardwick, Stockton-on-Tees, Cleveland, TS19 8PE
Orphenadrine is a specific skeletal muscle relaxant which does not impair either normal muscle tone or voluntary movement. It acts by blocking hyperstimulatory information in the mid-brain.' It has slight euphoric, antihistaminic and parasympathetic actions.2 It acts for 6-12 hours and by itself has little analgesic action. It has been suggested that the prevention of muscle spasm relieves much postoperative pain,3 and that orphenadrine, by reducing this spasm helps the analgesic effect of papaveretum in patients who suffer more than the average postoperative pain.4 The drug has also been used to relieve acute skeletal muscle spasm and pain associated with trauma around joints, rheumatoid arthritis, and the muscle rigidity of Parkinson's disease. This study has been designed to show that orphenadrine, when used as described, acts by reducing muscle spasm in the postoperative period, and delays the need for and prolongs the action of papaveretum.
Method Patient selection. Sixty patients having major abdominal operations were studied. They were placed randomly, using an electronically derived numerical series, into two groups relating to the drugs given. Anaesthetic technique. All patients were given nietoclopramide 20 mg and diazepam 20 mg orally 1-2 hours before operation. General anaesthesia was induced with thiopentone 2.5% 5 mg/kg body weight intravenously (preceded by atropine 0.6 mg), pentazocine 0.5 mg/kg body weight and haloperidol 0.05 mg/kg body weight. It was maintained with nitrous oxide 6 litres/min, oxygen 2 litres/min, and halothane 1% with suxamethonium 3&50 mg to facilitate tracheal intubation and pancuronium as required. The patients in Group A received orphenadrine 1 mg/kg up to 60 mg intravenously a t the end of the operation: the patients in Group B acted as controls. Observations. After the operation the patients were assessed hourly for appreciation of pain and placed in one of four grades. Since there were seven
trained nursing staff assessing the patients the following system was used. Grade 0 : the patients were asleep or, on questioning, said they felt no pain; Grade 1: on questioning the patients said that they felt pain but that it was bearable; Grade 2: on questioning the patients said that they felt pain and that they would like something to relieve it and Grade 3: the patients complained of pain spontaneously and asked for something to relieve it. The first dose of papaveretum was titrated intravenously, on request or when the level of pain reached Grade 2 at an hourly assessment, by a senior house officer. The assessments were made by trained nursing staff. None of them knew which patients had received orphenadrine. The second and subsequent doses of papaveretum were derived from the titrated dose adjusted to the nearest 5 mg and given intramuscularly when the pain had reached Grade 2 at one of the hourly assessments or Grade 3 at any time. The parameters selected for study were the elapsed time between the end of the operation and the first dose of papaveretum, the size of the first dose and the time between the first and second doses of papaveretum. Valid conclusions could not be drawn from the total doses given during the first 24 postoperative hours because absorption after intramuscular injection is unreliable. The pulse and respiration rates and blood pressure were measured immediately before the first dose of papavereturn was given and 1 hour later by trained nursing staff. The pulse rate was measured on the pulse meter of an SE Labs memory monitor and recorded to the nearest 10 beatslmin. The systolic blood pressure was measured by a Meditron F electric sphygmomanometer and the systolic pressure recorded to the nearest 10 mmHg. The respiration rate was measured by observation with a watch with a second hand.
Results Tables 1 and 2 show that the patients in the two groups were comparable. The means and standard deviations of the three parameters relating to pain relief are set out in Table 3. One hour after the first papaveretum
282
Forum Table 1.
Number of patients
Mean age (years+ SD)
Mean weight (kgk SD)
Mean duration operations (hrsf SD)
32 28
52.2 (k 15.9) 55.1 (f14.1)
64.1 (k8.93) 62.2 (k9.6)
1.83 (k0.73) 1.88 (k0.74)
Group A Group B
Table 2.
Abdominal hysterectomy Group A Group B
Large bowel surgery
4 5
Upper abdominal surgery
Renal operations
18 12
1 2
9 9
injection all the patients were placed in Grade 0 except four in the control group and three in the orphenadrine group who were placed in Grade 1. The second dose of papaveretum was given when the patients' pain appreciation reached Grade 2. Only two patients, both in the control group, felt nauseated. None vomited. The means and standard deviations of the observations made immediately before and one hour after the first papaveretum injection are presented in Table 4.
Discussion The decision about the time of administration of postoperative analgesic drugs is usually made by trained nursing staff in recovery or general surgical wards. Nurses wait, correctly, until the patient is fully recovered from general anaesthesia before giving the drug, and because the needs are so variable, the dose ordered is not always sufficient. Many patients suffer pain because requirements of papaveretum are poorly correlated with weight and
Table 3.
No. of cases
Group
Interval before first papaveretum injection in hr (+SD)
Mean of first papaveretum doses in mg (fSD)
Interval between first and second papaveretum injections in hr (fSD)
13.2 (7.2)
13.5 (8.4)
n.s.
P < 0'01
~~
Orphenadrine
32
Control
28
6.8 (5.1) P < 0.01 2.2 (1.45)
12.2 (4.0)
8.7 (7.1)
Table 4.
Group Orphenadrine Control
No. of cases
Mean pulse rate (+ SD)
Mean respiration rate (fSD)
Mean systolic blood pressure (kSD)
32 28
86 (f13) 85 (+ 12) 84 (f12) 85 (4 12)
24.5 rk4.7) 23.6 (k4.6) 21.9 (f3.6) 22.2 (f3.8)
135 (f16) 136 (+20) 138 ( k 2 1 ) 135 (+ 18)
Forum age and with the type of operation5 and the analgesic action of morphine is not related even to its serum concentration.6 Such pain not only causes distress but also postoperative nausea and vomiting.' The need for postoperative analgesia may be postponed for several hours by the use of orphenadrine in the way described in this study. This gives more time for the patient to recover from the anaesthesia and postoperative shock and since the analgesic action of papaveretum is prolonged the total dose required in the first 24 hr is reduced. There were no complications or side effects observed in the present series but since orphenadrine possesses muscle relaxant properties it might prolong the action of muscle relaxants. Orphenadrine also possesses parasympatholytic actions and should be used with caution in patients with hypertension, tachycardia, prostatism and chronic glaucoma.
Summary The action of orphenadrine when given towards the end of a general anaesthetic is described. It is shown to delay the need for postoperative analgesia and extend the analgesic action of papaveretum. Key words
283
PHARMACOLOGY ; orphenadrine. References 1. BIJLSMA,U.G., HARMS,A.F., FUNCKE,A.B.H., TERSTEEGE, H.M. & NAUPA,W.T. (1956) The pharm-
acology of ~-dimethylarninoethyl-2-methylbenzhydrylether hydrochloride (BS 5930). Archices Inrernarionales de Pharmacodynamie et cle Therapie, 106, 332. 2. CASS,L.J. & FREDERIK, W.S. (1964) An Evaluation of orphenadrine citrate in combination with APC as an analgesic. Current Therapeutic Research, 6 , 400. EGBERT, L.D., BATTIT, C.E., WELCH,C.E., BARTLETT, M.K. (1964) Reduction of postoperative pain by encouragement and instruction of patients. New England Journal of Medicine, 210, 825. FRY,E.N.S. (1978) Orphenadrine and postoperative pain. British Journal of Anaesthesia, 50, 205. FRY,E.N.S. & DESHPANDE, S. (1977) Postoperative analgesia by titration of papaveretum. British Meclical Journal, 2, 870. LAITINEN,L., KANTO, J., VAPAAVUORI, M. & VILIANEN,M.K. (1975) Morphine concentrations in plasma after intramuscular administration. British Journal of Anaesthesia, 41, 1265. ANDERSON, R. & KROHG,K . (1976) Pain as a major cause of postoperative nausea. Canadian Anaesthetists' Society Journal, 28, 366.
ANALGESIA; postoperative.
Anaesthesia, 1979, Volume 34, pages 283-287 IPPB and hypercapnia in respiratory failure: The effect of different concentrations of inspired oxygen on arterial blood gas tensions
I. D . Starke, BSc, MRCP, Registrar in Thoracic Medicine, B.A. Webber, MCSP, Assistant Superintendent Physiotherapist and M.A. Branthwaite, M D , MRCP, FFARCS, Consultant Anaesthetist and Physician, Brompton Hospital, Fulhani Road, London S W 3 6HP
Intermittent Positive Pressure Breathing (IPPB) is often used in conjunction with physiotherapy to aid removal of the bronchial secretions in patients with an exacerbation of chronic obstructive pulmonary disease. IPPB is a convenient means of administering bronchodilator drugs, and a possible additional benefit is to improve the distribution of alveolar ventilation.' IPPB devices can be powered by compressed gas which may be oxygen, air or an appropriate mixture. It is clearly desirable to increase the arterial oxygen saturation of patients in respiratory
failure both during periods of treatment with IPPB and during spontaneous breathing. Some spontaneously breathing patients in chronic respiratory failure with hypercapnia cannot be given oxygen safely because respiratory depression occurs and further elevation of the arterial carbon dioxide tension (Paco,) results.' This possibility is often used as an argument against using IPPB driven from an oxygen source. However, ventilation is assisted by the machine during the treatment period and any elevation in arterial oxygen tension (Pao,) would be likely to fall rapidly when the IPPB
281
Anaesthesia, 1979, Volume 34, pages 281-283
Postoperative analgesia using papaveretum and orphenadrine. A preliminary trial
E.N.S. Fry, MB, ChB, FFARCS, Consultant Anaesthetist, North Tees General Hospital, Hardwick, Stockton-on-Tees, Cleveland, TS19 8PE
Orphenadrine is a specific skeletal muscle relaxant which does not impair either normal muscle tone or voluntary movement. It acts by blocking hyperstimulatory information in the mid-brain.' It has slight euphoric, antihistaminic and parasympathetic actions.2 It acts for 6-12 hours and by itself has little analgesic action. It has been suggested that the prevention of muscle spasm relieves much postoperative pain,3 and that orphenadrine, by reducing this spasm helps the analgesic effect of papaveretum in patients who suffer more than the average postoperative pain.4 The drug has also been used to relieve acute skeletal muscle spasm and pain associated with trauma around joints, rheumatoid arthritis, and the muscle rigidity of Parkinson's disease. This study has been designed to show that orphenadrine, when used as described, acts by reducing muscle spasm in the postoperative period, and delays the need for and prolongs the action of papaveretum.
Method Patient selection. Sixty patients having major abdominal operations were studied. They were placed randomly, using an electronically derived numerical series, into two groups relating to the drugs given. Anaesthetic technique. All patients were given nietoclopramide 20 mg and diazepam 20 mg orally 1-2 hours before operation. General anaesthesia was induced with thiopentone 2.5% 5 mg/kg body weight intravenously (preceded by atropine 0.6 mg), pentazocine 0.5 mg/kg body weight and haloperidol 0.05 mg/kg body weight. It was maintained with nitrous oxide 6 litres/min, oxygen 2 litres/min, and halothane 1% with suxamethonium 3&50 mg to facilitate tracheal intubation and pancuronium as required. The patients in Group A received orphenadrine 1 mg/kg up to 60 mg intravenously a t the end of the operation: the patients in Group B acted as controls. Observations. After the operation the patients were assessed hourly for appreciation of pain and placed in one of four grades. Since there were seven
trained nursing staff assessing the patients the following system was used. Grade 0 : the patients were asleep or, on questioning, said they felt no pain; Grade 1: on questioning the patients said that they felt pain but that it was bearable; Grade 2: on questioning the patients said that they felt pain and that they would like something to relieve it and Grade 3: the patients complained of pain spontaneously and asked for something to relieve it. The first dose of papaveretum was titrated intravenously, on request or when the level of pain reached Grade 2 at an hourly assessment, by a senior house officer. The assessments were made by trained nursing staff. None of them knew which patients had received orphenadrine. The second and subsequent doses of papaveretum were derived from the titrated dose adjusted to the nearest 5 mg and given intramuscularly when the pain had reached Grade 2 at one of the hourly assessments or Grade 3 at any time. The parameters selected for study were the elapsed time between the end of the operation and the first dose of papaveretum, the size of the first dose and the time between the first and second doses of papaveretum. Valid conclusions could not be drawn from the total doses given during the first 24 postoperative hours because absorption after intramuscular injection is unreliable. The pulse and respiration rates and blood pressure were measured immediately before the first dose of papavereturn was given and 1 hour later by trained nursing staff. The pulse rate was measured on the pulse meter of an SE Labs memory monitor and recorded to the nearest 10 beatslmin. The systolic blood pressure was measured by a Meditron F electric sphygmomanometer and the systolic pressure recorded to the nearest 10 mmHg. The respiration rate was measured by observation with a watch with a second hand.
Results Tables 1 and 2 show that the patients in the two groups were comparable. The means and standard deviations of the three parameters relating to pain relief are set out in Table 3. One hour after the first papaveretum
282
Forum Table 1.
Number of patients
Mean age (years+ SD)
Mean weight (kgk SD)
Mean duration operations (hrsf SD)
32 28
52.2 (k 15.9) 55.1 (f14.1)
64.1 (k8.93) 62.2 (k9.6)
1.83 (k0.73) 1.88 (k0.74)
Group A Group B
Table 2.
Abdominal hysterectomy Group A Group B
Large bowel surgery
4 5
Upper abdominal surgery
Renal operations
18 12
1 2
9 9
injection all the patients were placed in Grade 0 except four in the control group and three in the orphenadrine group who were placed in Grade 1. The second dose of papaveretum was given when the patients' pain appreciation reached Grade 2. Only two patients, both in the control group, felt nauseated. None vomited. The means and standard deviations of the observations made immediately before and one hour after the first papaveretum injection are presented in Table 4.
Discussion The decision about the time of administration of postoperative analgesic drugs is usually made by trained nursing staff in recovery or general surgical wards. Nurses wait, correctly, until the patient is fully recovered from general anaesthesia before giving the drug, and because the needs are so variable, the dose ordered is not always sufficient. Many patients suffer pain because requirements of papaveretum are poorly correlated with weight and
Table 3.
No. of cases
Group
Interval before first papaveretum injection in hr (+SD)
Mean of first papaveretum doses in mg (fSD)
Interval between first and second papaveretum injections in hr (fSD)
13.2 (7.2)
13.5 (8.4)
n.s.
P < 0'01
~~
Orphenadrine
32
Control
28
6.8 (5.1) P < 0.01 2.2 (1.45)
12.2 (4.0)
8.7 (7.1)
Table 4.
Group Orphenadrine Control
No. of cases
Mean pulse rate (+ SD)
Mean respiration rate (fSD)
Mean systolic blood pressure (kSD)
32 28
86 (f13) 85 (+ 12) 84 (f12) 85 (4 12)
24.5 rk4.7) 23.6 (k4.6) 21.9 (f3.6) 22.2 (f3.8)
135 (f16) 136 (+20) 138 ( k 2 1 ) 135 (+ 18)
Forum age and with the type of operation5 and the analgesic action of morphine is not related even to its serum concentration.6 Such pain not only causes distress but also postoperative nausea and vomiting.' The need for postoperative analgesia may be postponed for several hours by the use of orphenadrine in the way described in this study. This gives more time for the patient to recover from the anaesthesia and postoperative shock and since the analgesic action of papaveretum is prolonged the total dose required in the first 24 hr is reduced. There were no complications or side effects observed in the present series but since orphenadrine possesses muscle relaxant properties it might prolong the action of muscle relaxants. Orphenadrine also possesses parasympatholytic actions and should be used with caution in patients with hypertension, tachycardia, prostatism and chronic glaucoma.
Summary The action of orphenadrine when given towards the end of a general anaesthetic is described. It is shown to delay the need for postoperative analgesia and extend the analgesic action of papaveretum. Key words
283
PHARMACOLOGY ; orphenadrine. References 1. BIJLSMA,U.G., HARMS,A.F., FUNCKE,A.B.H., TERSTEEGE, H.M. & NAUPA,W.T. (1956) The pharm-
acology of ~-dimethylarninoethyl-2-methylbenzhydrylether hydrochloride (BS 5930). Archices Inrernarionales de Pharmacodynamie et cle Therapie, 106, 332. 2. CASS,L.J. & FREDERIK, W.S. (1964) An Evaluation of orphenadrine citrate in combination with APC as an analgesic. Current Therapeutic Research, 6 , 400. EGBERT, L.D., BATTIT, C.E., WELCH,C.E., BARTLETT, M.K. (1964) Reduction of postoperative pain by encouragement and instruction of patients. New England Journal of Medicine, 210, 825. FRY,E.N.S. (1978) Orphenadrine and postoperative pain. British Journal of Anaesthesia, 50, 205. FRY,E.N.S. & DESHPANDE, S. (1977) Postoperative analgesia by titration of papaveretum. British Meclical Journal, 2, 870. LAITINEN,L., KANTO, J., VAPAAVUORI, M. & VILIANEN,M.K. (1975) Morphine concentrations in plasma after intramuscular administration. British Journal of Anaesthesia, 41, 1265. ANDERSON, R. & KROHG,K . (1976) Pain as a major cause of postoperative nausea. Canadian Anaesthetists' Society Journal, 28, 366.
ANALGESIA; postoperative.
Anaesthesia, 1979, Volume 34, pages 283-287 IPPB and hypercapnia in respiratory failure: The effect of different concentrations of inspired oxygen on arterial blood gas tensions
I. D . Starke, BSc, MRCP, Registrar in Thoracic Medicine, B.A. Webber, MCSP, Assistant Superintendent Physiotherapist and M.A. Branthwaite, M D , MRCP, FFARCS, Consultant Anaesthetist and Physician, Brompton Hospital, Fulhani Road, London S W 3 6HP
Intermittent Positive Pressure Breathing (IPPB) is often used in conjunction with physiotherapy to aid removal of the bronchial secretions in patients with an exacerbation of chronic obstructive pulmonary disease. IPPB is a convenient means of administering bronchodilator drugs, and a possible additional benefit is to improve the distribution of alveolar ventilation.' IPPB devices can be powered by compressed gas which may be oxygen, air or an appropriate mixture. It is clearly desirable to increase the arterial oxygen saturation of patients in respiratory
failure both during periods of treatment with IPPB and during spontaneous breathing. Some spontaneously breathing patients in chronic respiratory failure with hypercapnia cannot be given oxygen safely because respiratory depression occurs and further elevation of the arterial carbon dioxide tension (Paco,) results.' This possibility is often used as an argument against using IPPB driven from an oxygen source. However, ventilation is assisted by the machine during the treatment period and any elevation in arterial oxygen tension (Pao,) would be likely to fall rapidly when the IPPB
