The question as to whether the head and trunk of neurosurgery patients
should be elevated remains controversial. This question is particular
ly important when intracranial hypertension is present. Head up positi
on may have beneficial effects on intracranial pressure (ICP) via chan
ges in mean arterial pressure (MAP), airway pressure, central venous p
ressure and cerebro spinal fluid displacement. However, in some circum
stances, head up position may decrease MAP which in turn will result i
n a paradoxical rise in ICP through autoregulation mechanisms. Therefo
re, the degree of head elevation has to be titrated by evaluating the
most adequate cerebral perfusion pressure (CPP) for each patient by me
ans of transcranial Doppler or measurement of jugular venous blood oxy
gen saturation. Head elevation above 30 degrees should be avoided in a
ll cases. in most patients with intracranial hypertension, head and tr
unk elevation up to 30 degrees is useful in helping to decrease ICP, p
rovidest that a safe CPP of at least 70 mmHg or even 80 mmHg is mainta
ined. Patients in poor haemodynamic conditions are best nursed flat. C
PP is thus the most important factor in assessment and monitoring when
considering head elevation in patients with increased ICP. (C) 1998 E
lsevier, Paris.