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HORNER'S SYNDROME FOLLOWING OBSTETRIC EXTRADURAL BLOCK
Br.J. Anaesth. (1976), 48, 611
CORRESPONDENCE HORNER'S SYNDROME FOLLOWING OBSTETRIC EXTRADURAL BLOCK
D. V. THOMAS
Los Altos, California REFERENCES
Collier, C. B. (1975). Horner's syndrome following obstetric extradural block analgesia. Br. J. Anaesth., 47, 1342. Evans, J. M., Gaucz, C. A., and Watkins, G. (1975). Horner's syndrome as a complication of lumbar epidural block. Anaesthesia, 30, 774. Kepes, E. R., Martinez, L. R., Pantuck, E., and Stark, D. C. C. (1972). Horner's syndrome following caudal anesthesia. N.Y. State J. Med., 72, 946. Sir,—We were interested to read Dr Collier's description of a patient developing Horner's syndrome following obstetric extradural block analgesia (Collier, 1975). Until recently this syndrome had not been described as a result of lumbar extradural block, but had been noted as a complication of thoracic extradural block for the treatment of chest injuries (Mohan, Lloyd and Potter, 1973), and as a result of sacral extradural analgesia (Kepes et al., 1972; Mohan and Potter, 1975). In addition to Dr Collier's patient, two other cases of Horner's syndrome have been reported as a complication of lumbar extradural block in labour (Evans, Gauci and Watkins, 1975). In a prospective study of 32 patients undergoing lumbar extradural block in labour we found that the incidence of pupillary changes or other manifestations of cervical sympathetic blockade was as high as 75% (in preparation). There appears to be no obvious explanation for these distant effects. In one of our patients Horner's syndrome appeared following a test dose of only 2 ml of local analgesic solution. This phenomenon occurred in three out of 20
L. E. S. CARRIE J. MOHAN
Oxford REFERENCES
Collier, C. B. (1975). Horner's syndrome following obstetric extradural block analgesia. Br.J. Anaesth., 47, 1340. Evans, J. M., Gauci, C. A., and Watkins, G. (1975). Horner's syndrome as a complication of lumbar epidural block. Anaesthesia, 30, 774. Kepes, E. R., Martinez, L. R., Pantuck, E., and Stark, D. C. C. (1972). Horner's syndrome following caudal anesthesia. N.Y. State J. Med., 72, 946. Mohan, J., Lloyd, J. W., and Potter, J. M. (1973). Pupillary constriction following extradural analgesia. Injury, 5, 151. Potter, J. M. (1975). Pupillary constriction and ptosis following caudal epidural analgesia. Anaesthesia, 30, 769. RESPIRATORY EFFECTS OF LORAZEPAM
Sir,—In a recent publication from this laboratory (Utting and Pleuvry, 1975) the ventilatory response to carbon dioxide was examined in volunteers who received oral benzoctamine, diazepam or a placebo. It was concluded that neither benzoctamine nor diazepam was a suitable oral anxiolytic for use before operation in situations where respiratory depression was undesirable. Benzoctamine appeared to lack anxiolytic activity and diazepam depressed the ventilatory response to carbon dioxide in doses of as little as 5 mg. The same techniques have been used to investigate the respiratory effects of lorazepam which has been reported by Elliott and others (1971) to be free from depressant effects on the response to carbon dioxide. Eleven volunteers (six female) received a placebo, lorazepam 1 mg or lorazepam 2.5 mg orally using a doubleblind technique. Before, and at hourly intervals for 3 h after administration of the drug, measurements were made of minute volume, tidal volume, respiratory rate, systemic arterial pressure, pulse rate and the ventilatory response to carbon dioxide. The ventilatory response to carbon dioxide was assessed by a rebreathing method based on that described by Read (1967). Two methods were used to assess the effects of the tablets upon the ventilatory response to carbon dioxide. The first was to measure the slope of the response before and after taking the tablet and the second was to measure the displacement of the response on the Pco 2 axis after taking the tablet. The displacement of each carbon dioxide response line was calculated by reading Pco 2 at 30 litre/min and subtracting this from the pre-drug control value at 30 litre/min. Thus a positive value would be a displacement of the response to the left, suggesting respiratory stimulation. Similarly, a negative value would suggest respiratory depression. Ventilation at 30 litre/min was chosen as this value intersected the response lines obtained for all subjects without extrapolation. Subjective and
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
Sir,—This letter is in response to C. B. Collier's appeal for further case reports of this phenomenon (1975). At Palo Alto and Stanford University hospitals, where caudal and extradural analgesia for childbirth have been favourites for almost 30 years, a unilateral Horner's syndrome has occurred many times, yet, I am embarrassed to confess, we have never been sufficiently curious or energetic to report it. Although we have not kept a record I think that it occurs in about one case in a hundred; often it has gone unnoticed by the patients and the nurses, so perhaps if we looked for it systematically we should see it more often. It is hard to imagine any other explanation except a freak unilateral upward spread of anaesthetic solution. We have not noted any unusual tendency towards a high sensory blockade or serious hypotension, so I think that it is a curiosity which should not alarm us. For this reason, Dr Collier deserves credit for drawing your readers' attention to it. This condition has also been discussed by Kepes and colleagues (1972) and by Evans, Gauci and Watkins (1975).
patients who received sacral extradural analgesia (Mohan and Potter, 1975).
CORRESPONDENCE HORNER'S SYNDROME FOLLOWING OBSTETRIC EXTRADURAL BLOCK
D. V. THOMAS
Los Altos, California REFERENCES
Collier, C. B. (1975). Horner's syndrome following obstetric extradural block analgesia. Br. J. Anaesth., 47, 1342. Evans, J. M., Gaucz, C. A., and Watkins, G. (1975). Horner's syndrome as a complication of lumbar epidural block. Anaesthesia, 30, 774. Kepes, E. R., Martinez, L. R., Pantuck, E., and Stark, D. C. C. (1972). Horner's syndrome following caudal anesthesia. N.Y. State J. Med., 72, 946. Sir,—We were interested to read Dr Collier's description of a patient developing Horner's syndrome following obstetric extradural block analgesia (Collier, 1975). Until recently this syndrome had not been described as a result of lumbar extradural block, but had been noted as a complication of thoracic extradural block for the treatment of chest injuries (Mohan, Lloyd and Potter, 1973), and as a result of sacral extradural analgesia (Kepes et al., 1972; Mohan and Potter, 1975). In addition to Dr Collier's patient, two other cases of Horner's syndrome have been reported as a complication of lumbar extradural block in labour (Evans, Gauci and Watkins, 1975). In a prospective study of 32 patients undergoing lumbar extradural block in labour we found that the incidence of pupillary changes or other manifestations of cervical sympathetic blockade was as high as 75% (in preparation). There appears to be no obvious explanation for these distant effects. In one of our patients Horner's syndrome appeared following a test dose of only 2 ml of local analgesic solution. This phenomenon occurred in three out of 20
L. E. S. CARRIE J. MOHAN
Oxford REFERENCES
Collier, C. B. (1975). Horner's syndrome following obstetric extradural block analgesia. Br.J. Anaesth., 47, 1340. Evans, J. M., Gauci, C. A., and Watkins, G. (1975). Horner's syndrome as a complication of lumbar epidural block. Anaesthesia, 30, 774. Kepes, E. R., Martinez, L. R., Pantuck, E., and Stark, D. C. C. (1972). Horner's syndrome following caudal anesthesia. N.Y. State J. Med., 72, 946. Mohan, J., Lloyd, J. W., and Potter, J. M. (1973). Pupillary constriction following extradural analgesia. Injury, 5, 151. Potter, J. M. (1975). Pupillary constriction and ptosis following caudal epidural analgesia. Anaesthesia, 30, 769. RESPIRATORY EFFECTS OF LORAZEPAM
Sir,—In a recent publication from this laboratory (Utting and Pleuvry, 1975) the ventilatory response to carbon dioxide was examined in volunteers who received oral benzoctamine, diazepam or a placebo. It was concluded that neither benzoctamine nor diazepam was a suitable oral anxiolytic for use before operation in situations where respiratory depression was undesirable. Benzoctamine appeared to lack anxiolytic activity and diazepam depressed the ventilatory response to carbon dioxide in doses of as little as 5 mg. The same techniques have been used to investigate the respiratory effects of lorazepam which has been reported by Elliott and others (1971) to be free from depressant effects on the response to carbon dioxide. Eleven volunteers (six female) received a placebo, lorazepam 1 mg or lorazepam 2.5 mg orally using a doubleblind technique. Before, and at hourly intervals for 3 h after administration of the drug, measurements were made of minute volume, tidal volume, respiratory rate, systemic arterial pressure, pulse rate and the ventilatory response to carbon dioxide. The ventilatory response to carbon dioxide was assessed by a rebreathing method based on that described by Read (1967). Two methods were used to assess the effects of the tablets upon the ventilatory response to carbon dioxide. The first was to measure the slope of the response before and after taking the tablet and the second was to measure the displacement of the response on the Pco 2 axis after taking the tablet. The displacement of each carbon dioxide response line was calculated by reading Pco 2 at 30 litre/min and subtracting this from the pre-drug control value at 30 litre/min. Thus a positive value would be a displacement of the response to the left, suggesting respiratory stimulation. Similarly, a negative value would suggest respiratory depression. Ventilation at 30 litre/min was chosen as this value intersected the response lines obtained for all subjects without extrapolation. Subjective and
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
Sir,—This letter is in response to C. B. Collier's appeal for further case reports of this phenomenon (1975). At Palo Alto and Stanford University hospitals, where caudal and extradural analgesia for childbirth have been favourites for almost 30 years, a unilateral Horner's syndrome has occurred many times, yet, I am embarrassed to confess, we have never been sufficiently curious or energetic to report it. Although we have not kept a record I think that it occurs in about one case in a hundred; often it has gone unnoticed by the patients and the nurses, so perhaps if we looked for it systematically we should see it more often. It is hard to imagine any other explanation except a freak unilateral upward spread of anaesthetic solution. We have not noted any unusual tendency towards a high sensory blockade or serious hypotension, so I think that it is a curiosity which should not alarm us. For this reason, Dr Collier deserves credit for drawing your readers' attention to it. This condition has also been discussed by Kepes and colleagues (1972) and by Evans, Gauci and Watkins (1975).
patients who received sacral extradural analgesia (Mohan and Potter, 1975).