Attendants should use a thermometer to maintain an even temperature in the sickroom because sleep deprivation impairs their perception of temperature.

Original passage

So far as possible an even temperature should be maintained in the sickroom. The thermometer should be consulted. Those who have the care of the sick, being often deprived of sleep or awakened in the night to attend to the patient, are liable to chilliness and are not good judges of a healthful temperature.