2. Set the coolant temperature in the cooling unit to

20°C.

3. Place the mattress inside an incubator with power

turned off.

4. Undress the infant down to small diaper to maximize

skin contact with mattress for optimal heat exchange.

5. Secure a rectal temperature probe to 6 cm (see Fig.

45.2E).

6. Place the infant on the mattress inside the incubator.

7. When the rectal temperature reaches 35°C, increase

the set temperature in the cooling machine to 25°C.

8. To maintain the rectal temperature between 33°C and

34°C, set temperature in the cooling machine to

between 25°C and 30°C. This will vary with the body

weight and heat production of the infant.

9. To rewarm the infant at 0.5°C/h, increase the set fluid

temperature in the cooling machine by approximately

0.3°C/30 minutes. The core temperature will increase

with increases in the mattress temperature. This is very

difficult to get “right” and requires experience.

10.When core temperature of (36.5°C) has been reached, set

the incubator temperature to maintain normothermia.

11. Remove the mattress.

12. Monitor rectal temperature for at least 24 hours after

achieving normothermia (36.5°C) (28).

Pitfalls

1. Intermittent manual adjustment of coolant fluid temperature is required.

2. Overshoot of core temperature during induction of

hypothermia.

3. Large swings in rectal temperature (29) (Fig. 45.11).

Cooling Using a Servocontrolled Cooling

Machine

The servocontrolled cooling systems cool and maintain the

core temperature by altering the temperature of the cooling

fluid automatically, based on the core and surface temperature feedback to the system. The infant can be placed inside

an incubator or preferably in an open bed.

1. The CritiCool (Fig. 45.12) (MTRE Advanced

Technologies Ltd, Yavne, Israel). Temperature

Management Unit

Other Equipment

a. Power cable

b. Connecting tubes

c. Cure wrap (MTRE Advanced Technologies Ltd,

Yavne, Israel)

334 Section IX ■ Miscellaneous Procedures

A B

D

E

C

F

Female end of connecting

tube to curewrap

< 3.5kg

Curewrap

Green surface temperature sensor

Connecting tubes to temperature

management unit

Water tank

Rectal temperature sensor tip

Cooling during

transport

Surface temperature sensor tip

Grey core (rectal) temperature sensor

> 3.5kg