Preoperative Hypothermia Clinical Trial
Official title:
Active Warming for Elective Caesarean Section - a RCT
During anaesthesia for caesarean section it is common to lose heat and become hypothermic,
(<36 degrees C). In order to try and avoid this all women are given warmed intravenous fluid
and insulated from cold surfaces. There are also 2 types of machine available to actively
warm women;
1. Forced Air Warming - that uses a disposable sheet the woman lies upon with lots of air
pockets that have warm air blown into them continuously by a fan.
2. Conduction Warming Mattress - a thin mattress which covers the operating table and the
woman lies on top. The padded mattress has strips of material that heat up when
electricity passes through it, similar to a normal electric blanket.
We plan to carry out a randomised controlled trial to compare these 2 methods with the
current practice of no active warming.
The hypothesis for this study is that active warming women during elective caesarean section
prevents women's temperature from dropping and keeps them more comfortable than if active
warming were not used.
When a baby is delivered by a surgical procedure (a caesarean section) the woman will
usually have a "spinal" anaesthetic. With a "spinal", local anaesthetic is injected into the
spinal fluid to make the woman numb from her chest to her feet, allowing her to be
comfortable but awake during the birth. During this type of anaesthetic it is common to lose
heat and become cold or "hypothermic" measured as less than 36 degrees Celsius. Becoming
this cold can be uncomfortable for the woman but also causes other problems. It can make
blood clotting less effective, alter the way wounds heal afterwards and make the woman more
likely to develop infections or problems related to her heart and lungs.
To help keep their temperature stable, the investigators give all women fluid into the veins
that is already warm and ensure that they are well insulated from any cold surfaces. There
are two machines that the investigators can also use to actively warm patients but these are
not yet used in every case. The first method is called "Forced Air Warming" and uses a
special disposable sheet the woman lies upon with lots of air pockets that have warm air
blown into them continuously by a fan. The woman is surrounded by these pockets of warm air,
which help to warm her and also insulate against heat loss. The second method is called a
"Conduction Warming Mattress" and uses a thin mattress which covers the operating table and
the woman lies on top. The padded mattress has strips of material that heat up when
electricity passes through it, similar to a normal electric blanket.
The investigators have already looked at the records of some women having caesarean sections
in our hospital and found that both forced air warming and conduction mattress warming seem
to help them stay warm. However, the investigators would like to study this in more detail
and prove scientifically whether these methods are effective. Our aim in this study is to
see if warming machines can help prevent women getting too cold, and prove scientifically
whether one is more effective.
The hypothesis for this study is that active warming women during elective caesarean section
prevents women's temperature from dropping and keeps them more comfortable than if active
warming were not used.
The women will have exactly the same anaesthetic as they would have had if they were not in
the study. If a woman agrees to be in the study she will be chosen randomly to receive
either, normal care (including warmed fluids but no warming machines), additional warming
with forced air or additional warming by conduction mattress. Her temperature will be
measured at regular intervals before, during and after the caesarean section, at the same
time she will be asked to score herself on a thermal comfort scale. The results will be
analysed to compare the temperature changes in each group.
The investigators hope that the active warming machines will keep body temperature stable
and prevent hypothermia. If the investigators find out that these machines prevent women
getting cold, they can ensure that the most effective methods of warming during caesarean
section operations are used and minimise problems due to becoming cold.
;
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Prevention