Transcript Slide 1

INTRAPARTUM PYREXIA IS NOT
THE RESPONSIBILITY OF THE
ANAESTHETIST
- OR IS IT?
Subcommittee Obstetric Anaesthesia and
Intensive care Annual meeting
5TH March 2009
P J Steer
Professor of Obstetrics
Academic Department of Obstetrics and Gynaecology
Chelsea and Westminster Hospital
© Imperial College London
1
Study of Cord artery pH,
St Mary’s 1984 (n =1216)
Steer et al, Obstet Gynecol 74:715-721, 1989
% Incidence
25
of pyrexia > 37.5 deg C
20
15
Epidural
10
5
No Epidural
0
0-4
-8
-12
-16
-20
Duration of labour (hours)
-24
24+
Investigation of fetal
temperature during labour
• Thermistor attached to the fetal surface of a Showell
Surgicraft electrode
• Mike Carter (bioengineer)
• Luca Fusi (British Council Research Fellow)
Thermistor here
Mike Carter
L. Fusi, P. J. Steer, M. J. A. Maresh, and R. W. Beard.
Maternal pyrexia associated with the use of epidural anaesthesia in labour.
Lancet i:1250-1252, 1989. 82 citations to April 2008
OVERNIGHT INCREASE IN EPIDURAL
RATE FROM 1% TO 83%
Tripler Army Medical Center, Hawaii, October 1993
• Temperature in labour > 37.50C rose from 8.2% to
26.2%
• Temperature > 380C rose from 0.6% to 11%
M. K. Yancey, et al
epidural analgesia
and intrapartum
maternal hyperthermia.
Obstet Gynecol
98:763-770, 2001.
The temperature team 1992-5
Macaulay, Steer, Bond & Randall
Main heat
loss through
placenta
(‘heat
exchanger’)
Fetal core
temperature
1oC warmer
than mother
(2nd law of
thermodynamics)
Probe for
measuring
maternal
and
fetal
temperature
in labour
Fetal scalp
Lower uterine
segment
EPIDURAL
EPIDURAL
J. H. Macaulay, K. Bond, and P. J. Steer.
Epidural analgesia in labor and fetal hyperthermia.
Obstet Gynecol 80:665-669, 1992. Cited 36 times to April 2008
RUPTURED MEMBRANES STUDY 1997-2000
Dick Marjanovic
Charlotte Patient
RUPTURED MEMBRANES
STUDY
• 52 women with term prelabour rupture
of the amniotic membranes
• 50 chose epidural anaesthesia
• Intrapartum pyrexia (>37.5oC) was
common:
– oral
25%
– uterine
77%
– fetal scalp
94%
Sujoy Banerjee 2001-3
S. Banerjee, P. Cashman, S. M. Yentis, and P. J. Steer.
Maternal Temperature Monitoring During Labor:
Concordance and Variability Among Monitoring Sites.
Obstet.Gynecol. 103 (2):287-293, 2004.
Intrauterine temperature probe
Skin probe
Powerlab
Mean temperature at different sites
by duration of labour
The incidence of fever in ILEA was
significantly lower at four hours
(2/42, vs. 10/44, P = 0.036)
V. R. Mantha, M. C. Vallejo, V. Ramesh, A. L. Phelps, and S. Ramanathan.
Int.J Obstet Anesth. 17 (2):123-129, 2008.
Why do epidurals cause a rise in
maternal temperature during
labour?
Body temperature is a balance
between
heat production and heat loss
• Metabolism
• Muscular activity • uterine contractions
•
•
•
•
•
Conduction
Convection
Radiation
Hyperventilation
Sweating (minimum
25% of heat loss,
rising to 100% if
ambient temperature
370C - Heat of
vaporisation of water
is about 580
Calories/litre)
Body temperature during labour
• Heat production is high due to muscular
activity (especially uterine contraction)
• Ambient temperature is high (260C)
• Heat loss is normally high due to:
– hyperventilation
– Vasodilatation
– Sweating
Effect of epidurals in labour
• Increase
vasodilatation
• Decrease
skeletal muscle
activity
• Abolish
hyperventilation
• Promote shivering
• Abolish sweating
over the lower half
of the body
• Modify temperature
information input to
hypothalamus
CONCLUSION
• EPIDURALS CAUSE A RISE IN
MATERNAL TEMPERATURE DURING
LABOUR
DOES THIS MATTER?
1657 nulliparous women with term pregnancies and
singleton vertex fetuses who were afebrile at admission
35
30
25
20
No Epidural
Epidural
15
10
5
0
Intrapartum Neonatal
fever
sepsis
workup
Neonatal
antibiotic
treatment
E. Lieberman, J. M. Lang, F. Jr Frigoletto, D. K. Richardson, S. A. Ringer, and A. Cohen.
Epidural analgesia, intrapartum fever, and neonatal sepsis evaluation.
Pediatrics 99 (3):415-419, 1997.
INTRAPARTUM MATERNAL FEVER
AND NEONATAL OUTCOME
• 1218 nulliparous women in spontaneous labour
• labours with signs of infection were excluded
• 123 women had fever > 380C; 120 had epidurals
Fever
•
•
•
•
% 1 min Apgar score <1
% Hypotonia
% Oxygen therapy
% Neonatal seizures
23
5
8.2
3.3
Lieberman et al, Pediatrics, 105; 8-13, 2000
No fever
8
0.5
1.3
0.2
INTRAPARTUM MATERNAL FEVER
AND
NEONATAL ENCEPHALOPATHY
“Maternal pyrexia (odds ratio 3.82),
a persistent occipitoposterior position (4.29),
and an acute intrapartum event (4.44)
were all risk factors for
newborn encephalopathy”
N. Badawi, J. J. Kurinczuk, J. M. Keogh, L. M. Alessandri, F. O'Sullivan,
Burton, PR, P. J. Pemberton, and F. J. Stanley.
Intrapartum risk factors for newborn encephalopathy:
the Western Australian case-control study.
BMJ 317 (7172):1554-1558, 1998.
INTRAPARTUM MATERNAL FEVER
AND
CEREBRAL PALSY
“Maternal fever exceeding 38OC in labor
was associated with an
increased risk of unexplained cerebral palsy
(odds ratio 9.3, 95% CI 2.7-31.0)”
J. K. Grether and K. B. Nelson.
Maternal infection and cerebral palsy in infants of normal birth weight.
JAMA 278 (3):207-211, 1997.
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
80
70
60
50
40
30
20
10
0
0
5
10
Duration of labour (1hr groups)
15
20
25
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
10
8
6
4
epidural in S1
no epidural
2
0
0
6
12
Duration of labour (2hr groups)
18
24
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
NW Thames database – spontaneous onset of labour
gestation 37-42 weeks; 358,979 births 1988-2000
Perinatal outcome – multiple regression
Intrapartum or
neonatal death
Neonatal
convulsions
Overall
R = 0.009
p = 0.00003
R = 0.007
p = 0.02
Epidural
p = 0.3
p = 0.9
Duration of
labour
p = 0.04
p = 0.1
Pyrexia in
labour
p = 0.000025
p = 0.018
Where both factors coexisted, the risk was 12.5%.......
EVIDENCE FOR NEONATAL COOLING BEING
PROTECTIVE AGAINST THE EFFECTS OF
HYPOXIA
• Selective head cooling with mild systemic
hypothermia after neonatal encephalopathy:
multicentre randomised trial
–
P. D. Gluckman, J. S. Wyatt, D. Azzopardi, R. Ballard, A. D. Edwards, D. M. Ferriero, R. A.
Polin, C. M. Robertson, M.. Thoresen, A. Whitelaw, and A. J. Gunn.
– Lancet 365:663-670, 2005.
• Whole-body hypothermia for neonates with
hypoxic-ischemic encephalopathy
–
S. Shankaran, A. R. Laptook, R. A. Ehrenkranz, J. E. Tyson, S. A. McDonald, E. F. Donovan, A.
A. Fanaroff, W. K. Poole, L. L. Wright, R. D. Higgins, N. N. Finer, W. A. Carlo, S. Duara, W. Oh,
C. M. Cotten, D. K. Stevenson, B. J. Stoll, J. A. Lemons, R. Guillet, and A. H. Jobe..
– N.Engl.J Med. 353 (15):1574-1584, 2005.
CONCLUSIONS
• The commonest cause of intrapartum pyrexia in
modern practice is the use of epidural anaesthesia
• Pyrexia in labour has a strong association with
neonatal encephalopathy and cerebral palsy
• Preventing temperature rise is known to limit hypoxic
ischaemic damage in animals and stroke victims
• Neonatal brain cooling can reduce damage in
hypoxic ischaemic encephalopathy
• Trials of temperature control in labour in relation to
both short term and long term outcome are needed
Banerjee S & Steer PJ
International Journal of Obstetric Anaesthesia (2003) 12; 280-286
Effect of paracetamol
39.5
Temperature
39.0
38.5
38.0
37.5
37.0
-4.0
-3.0
-2.0
-1.0
.0
1.0
2.0
3.0
4.0
5.0
6.0
Time in hours from paracetamol
S. Banerjee, P. Cashman, S. M. Yentis, and P. J. Steer.
Maternal Temperature Monitoring During Labor: Concordance and Variability Among Monitoring Sites.
Obstet.Gynecol. 103 (2):287-293, 2004
Prophylactic acetaminophen does not prevent
epidural fever in nulliparous women: a doubleblind placebo-controlled trial.
• 42 women assigned at random to 650mg
paracetamol PR immediately after epidural
anaesthesia and then 4hrly until delivery
• Maternal pyrexia >38oC occurred in 25% of
each group
• There was no evidence of infection in either
group
L. Goetzl, J. Rivers, T. Evans, D. R. Citron, B. E. Richardson, E. Lieberman, and M. S. Suresh.
J.Perinatol. 24 (8):471-475, 2004.
Goetzl et al 2006
• Placebo, methylprednisolone 25mg 8
hourly (low dose) or 100mg 4 hourly
(high dose)
• Randomised 101 to placebo, 50 to low
dose and 49 to high dose
Goetzl et al 2006
placebo
Low dose High dose
Maternal
fever >=380C
34%
21.8%
2%
Neonatal
sepsis
evaluation
24%
17.8%
4.1%
“A Cobber is a
cooling neck
wrap which
can be worn
around the
neck or
forehead. It
actually
reduces your
body
temperature
by 3-4
degrees.”
http://www.coolgardenstuff.com/products2/prods/COBBER.html
Vaibhav Sharma
Neck Cooler study
March
2004
Cooling with the Cobber following a hot bath
.2
Initial
Temperature
380C
0.0
-.2
-.4
-.6
-.8
5 students
-1.0
control
-1.2
-1.4
neck cooler
0
2
4
6
Time in minutes
8
10
12
14
16
18
20
Time (hours)
05:51:50
05:35:50
05:19:50
05:03:50
04:47:50
04:31:50
04:15:50
03:59:50
03:43:50
03:27:50
03:11:50
02:55:50
02:39:50
02:23:50
38
02:07:50
01:51:50
01:35:50
01:19:50
01:03:50
00:47:50
00:31:50
00:15:50
Time (hrs)
Case
1
Intrauterine temperature (Deg C)
39
38.5
Neck
Cooler
37.5
37
36.5
Time (hours)
02:36:20
02:27:00
39.5
02:17:40
Intrauterine temperature (Deg C)
02:08:20
01:59:00
01:49:40
Neck coolers
01:40:20
01:31:00
01:21:40
38.5
01:12:20
01:03:00
00:53:40
00:44:20
00:35:00
00:25:40
00:16:20
00:07:00
39
00:00:05
Time (hrs)
Case
4
Intrauterine temperature (Deg C)
40.5
FHR 175bpm
Meconium ++
40
Oral temperature (Deg C)
Maternal Shivering
+++
FBS pH 7.39
Top-up
Felt
Cold
38
37.5
37
36.5
Resuscitation
of the baby
in case 4
N A Richards, Z S Maharoullee, S M Yentis, P J Steer
Pilot study of neck warmers 2008
Nicci Richards
Neck warmer study
2008 –
10 in each group
Randomised trial of neck warmers in 200 parturients
starting next week
Watch this space!