British Journal of Anaesthesia 1991; 67: 565-568
MATERNAL TEMPERATURE REGULATION DURING EXTRADURAL ANALGESIA FOR LABOUR
have simple, non-invasive devices become available for routine, clinical measurement of TM We have studied the effect of analgesia on temperature. An additional factor which may complicate maternal temperature (oral and tympanic meminterpretation of maternal temperature during brane) progression in 53 women during normal labour is the type of analgesia used. Fusi and spontaneous labour. Three groups were studied: two received extradural analgesia with a con- colleagues reported a significant increase in temtinuous infusion of 0.25% bupivacaine with or perature (oral and vaginal) when extradural without the addition of fentanyl; the third group analgesia was used during labour [7]. This received only parenteral opioid analgesia. All temperature increase was seen even in the absence patients were afebrile and without clinical evi- of signs of maternal infection. They postulated dence of infection at the beginning of the study. that extradurally induced sympathectomy may Both groups of patients receiving extradural inhibit heat dissipation, thus resulting in an analgesia had a consistent and significant in- increase in temperature as labour progressed. In crease in temperature after approximately 5 h of contrast, other investigators have noted that analgesia; no such trend was observed in the extradural analgesia may be associated with parenteral opioid group. Alterations in mechan- hypothermia, resulting from redistribution of heat isms of heat dissipation may explain these from the core to the periphery, and thus heat loss to the environment [8]. Recent evidence suggests findings. that extradural opioids may also affect thermoregulation during anaesthesia [9, 10]. KEY WORDS The present study was conducted to investigate Anaesthesia: obstetric. Anaesthetic techniques: extradural. further the changes in oral and TM temperature Analgesics: opioid. Temperature: maternal. during normal labour, with and without extradural analgesia. In addition, we sought to determine the Infection is a common cause of maternal and effect of the addition of an opioid (fentanyl) to the neonatal morbidity during labour [1]. Thus close extradural analgesia. monitoring of maternal temperature is performed routinely in most obstetric units. However, sevPATIENTS AND METHODS eral factors may affect the accuracy of temperature measurement during labour. Hyperventilation, We investigated prospectively 53 women in active sucking ice, and oxygen administration may affect labour who fulfilled the following criteria: sponoral temperature [2]. Similarly, increased lower taneous onset of labour at term gestation (37-41 extremity blood flow caused by extradural analgesia-induced sympathetic block may render WILLIAM R. CAMANN, M.D. ; LAUREL A. HORTVET, M.D. ; NIALL rectal, vaginal or bladder temperature unreliable HUGHES, M.B., F.F.A.R.C.S.I.; ANGELA M. BAOER, M.D.; SANJAY [3,4]. Excessive perspiration during arduous DATTA, M.B., F.C.ANAES. ; Department of Anaesthesia, Brigham labour may alter axillary temperature. Whilst and Women's Hospital, 75 Francis Street, Boston, Massa02115, U.S.A. Accepted for Publication: April 29, tympanic membrane (TM) temperature reflects chusetts 1991. core temperature reliably [5,6], only recently Correspondence to W. R. C. SUMMARY
Downloaded from http://bja.oxfordjournals.org/ at The University of British Colombia Library on June 26, 2015
W. R. CAMANN, L. A. HORTVET, N. HUGHES, A. M. BADER AND S. DATTA
566
BRITISH JOURNAL OF ANAESTHESIA
fashion, using sequentially numbered, sealed opaque envelopes. Both had extradural blocks initiated with 0.25 % bupivacaine 8-12 ml. Thereafter, one group (extradural-B, n = 20) had a Parenteral continuous extradural infusion of 0.25 % bupivopioid Extradural-B Extradural-BF acaine and the other (extradural-BF, n = 20) had (TI = 20) (n = 20) (n = 13) continuous infusion of 0.25 % bupivacaine with Age (yr) 27(18-41) 29(17-41) 28(18-38) fentanyl citrate, 2 ug ml"1. The infusions in both Height (cm) 168(3) 168(5) 168(3) groups were maintained at 10 ml h"1 with a Weight (kg) 74(6) 74(6) 74(9) volumetric infusion pump. All extradural infusParity ions were prepared by an anaesthetist not 15 16 11 Primiparous involved in the study, and the investigators were 5 4 2 Multiparous not aware of the patient's group assignment. 12.2 (6.9) 9.5 (3.9) Rupture of 9.6 (3.6) membranes to Thirteen women who received only opioid andelivery (h) algesia served as a control group. All extradural 115(49)* 90(42) Duration second 60(32) anaesthetics were begun when cervical dilatation stage (min) was between 3 and 5 cm. All women received i.v. infusions of lactated Ringer's solution at room temperature and continuous electronic fetal heart 38.5rate monitoring was used during labour. u 38 Maternal temperature was measured using an 8o° oral sublingual thermometer (IVAC Corporation £37.5 Model No. 2085, San Diego, CA, U.S.A.) 3 S 37 and a tympanic membrane temperature sensor CD Q. (Ototemp 3000, Infrared Tympanic Temperature E36.5 Sensor, Exergen Corporation, Newton, MA, U.S.A.). All temperature measurements were .« 36 c performed in accordance with the manufacturers' E
36.8 -
g
36.6 H
a.
E
36.4 36.2 0
2
4
6 8 10 Time (h) FIG. 2. Mean (SE) tympanic temperatures during labour in the extradural-BF (O)J extradural-B (X) and opioid ( • ) groups. P < 0.01: "compared with extradural-BF and extradural-B groups; -|"|-compared with pre-extradural temperature (ANOVA). 190 180
170 160 150 -I 140 130 0 0 0
120 110
MATERNAL TEMPERATURE REGULATION DURING EXTRADURAL ANALGESIA FOR LABOUR
have simple, non-invasive devices become available for routine, clinical measurement of TM We have studied the effect of analgesia on temperature. An additional factor which may complicate maternal temperature (oral and tympanic meminterpretation of maternal temperature during brane) progression in 53 women during normal labour is the type of analgesia used. Fusi and spontaneous labour. Three groups were studied: two received extradural analgesia with a con- colleagues reported a significant increase in temtinuous infusion of 0.25% bupivacaine with or perature (oral and vaginal) when extradural without the addition of fentanyl; the third group analgesia was used during labour [7]. This received only parenteral opioid analgesia. All temperature increase was seen even in the absence patients were afebrile and without clinical evi- of signs of maternal infection. They postulated dence of infection at the beginning of the study. that extradurally induced sympathectomy may Both groups of patients receiving extradural inhibit heat dissipation, thus resulting in an analgesia had a consistent and significant in- increase in temperature as labour progressed. In crease in temperature after approximately 5 h of contrast, other investigators have noted that analgesia; no such trend was observed in the extradural analgesia may be associated with parenteral opioid group. Alterations in mechan- hypothermia, resulting from redistribution of heat isms of heat dissipation may explain these from the core to the periphery, and thus heat loss to the environment [8]. Recent evidence suggests findings. that extradural opioids may also affect thermoregulation during anaesthesia [9, 10]. KEY WORDS The present study was conducted to investigate Anaesthesia: obstetric. Anaesthetic techniques: extradural. further the changes in oral and TM temperature Analgesics: opioid. Temperature: maternal. during normal labour, with and without extradural analgesia. In addition, we sought to determine the Infection is a common cause of maternal and effect of the addition of an opioid (fentanyl) to the neonatal morbidity during labour [1]. Thus close extradural analgesia. monitoring of maternal temperature is performed routinely in most obstetric units. However, sevPATIENTS AND METHODS eral factors may affect the accuracy of temperature measurement during labour. Hyperventilation, We investigated prospectively 53 women in active sucking ice, and oxygen administration may affect labour who fulfilled the following criteria: sponoral temperature [2]. Similarly, increased lower taneous onset of labour at term gestation (37-41 extremity blood flow caused by extradural analgesia-induced sympathetic block may render WILLIAM R. CAMANN, M.D. ; LAUREL A. HORTVET, M.D. ; NIALL rectal, vaginal or bladder temperature unreliable HUGHES, M.B., F.F.A.R.C.S.I.; ANGELA M. BAOER, M.D.; SANJAY [3,4]. Excessive perspiration during arduous DATTA, M.B., F.C.ANAES. ; Department of Anaesthesia, Brigham labour may alter axillary temperature. Whilst and Women's Hospital, 75 Francis Street, Boston, Massa02115, U.S.A. Accepted for Publication: April 29, tympanic membrane (TM) temperature reflects chusetts 1991. core temperature reliably [5,6], only recently Correspondence to W. R. C. SUMMARY
Downloaded from http://bja.oxfordjournals.org/ at The University of British Colombia Library on June 26, 2015
W. R. CAMANN, L. A. HORTVET, N. HUGHES, A. M. BADER AND S. DATTA
566
BRITISH JOURNAL OF ANAESTHESIA
fashion, using sequentially numbered, sealed opaque envelopes. Both had extradural blocks initiated with 0.25 % bupivacaine 8-12 ml. Thereafter, one group (extradural-B, n = 20) had a Parenteral continuous extradural infusion of 0.25 % bupivopioid Extradural-B Extradural-BF acaine and the other (extradural-BF, n = 20) had (TI = 20) (n = 20) (n = 13) continuous infusion of 0.25 % bupivacaine with Age (yr) 27(18-41) 29(17-41) 28(18-38) fentanyl citrate, 2 ug ml"1. The infusions in both Height (cm) 168(3) 168(5) 168(3) groups were maintained at 10 ml h"1 with a Weight (kg) 74(6) 74(6) 74(9) volumetric infusion pump. All extradural infusParity ions were prepared by an anaesthetist not 15 16 11 Primiparous involved in the study, and the investigators were 5 4 2 Multiparous not aware of the patient's group assignment. 12.2 (6.9) 9.5 (3.9) Rupture of 9.6 (3.6) membranes to Thirteen women who received only opioid andelivery (h) algesia served as a control group. All extradural 115(49)* 90(42) Duration second 60(32) anaesthetics were begun when cervical dilatation stage (min) was between 3 and 5 cm. All women received i.v. infusions of lactated Ringer's solution at room temperature and continuous electronic fetal heart 38.5rate monitoring was used during labour. u 38 Maternal temperature was measured using an 8o° oral sublingual thermometer (IVAC Corporation £37.5 Model No. 2085, San Diego, CA, U.S.A.) 3 S 37 and a tympanic membrane temperature sensor CD Q. (Ototemp 3000, Infrared Tympanic Temperature E36.5 Sensor, Exergen Corporation, Newton, MA, U.S.A.). All temperature measurements were .« 36 c performed in accordance with the manufacturers' E
36.8 -
g
36.6 H
a.
E
36.4 36.2 0
2
4
6 8 10 Time (h) FIG. 2. Mean (SE) tympanic temperatures during labour in the extradural-BF (O)J extradural-B (X) and opioid ( • ) groups. P < 0.01: "compared with extradural-BF and extradural-B groups; -|"|-compared with pre-extradural temperature (ANOVA). 190 180
170 160 150 -I 140 130 0 0 0
120 110
