Arch
Surg 2001 Oct;136(10):1118-23
Hypotension,
hypoxia, and head injury: frequency, duration, and
consequences.
Manley G,
Knudson MM, Morabito D, Damron S, Erickson V,
Pitts L.
Department
of Surgery, San Francisco General Hospital, Ward
3A, 1001 Potrero Ave, San Francisco, CA 94110,
USA.
BACKGROUND: Retrospective studies have suggested
an association between systemic hypotension and
hypoxia and worsened outcome from traumatic brain
injury. Little is known, however, about the
frequency and duration of these potentially
preventable causes of secondary brain injury.
HYPOTHESIS: Early episodes of hypoxia and
hypotension occurring during initial resuscitation
will have a significant impact on outcome
following traumatic brain injury. DESIGN:
Prospective cohort study. SETTING: Urban level I
trauma center. PATIENTS: Patients with a traumatic
brain injury who had a Glasgow Coma Score of 12 or
less within the first 24 hours of admission to the
hospital and computed tomographic scan results
demonstrating intracranial pathologic features.
Patients who died in the emergency department were
excluded from the study. MAIN OUTCOME MEASURES:
Automated blood pressure and pulse oximetry
readings were collected prospectively from the
time of arrival through initial resuscitation. The
number and duration of hypotensive (systolic blood
pressure, < or =90 mm Hg) and hypoxic (oxygen
saturation, < or =92%) events were analyzed for
their association with mortality and neurological
outcome. RESULTS: One hundred seven patients met
the enrollment criteria (median Glasgow Coma
Score, 7). Overall mortality was 43%. Twenty-six
patients (24%) had hypotension while in the
emergency department, with an average of 1.5
episodes per patient (mean duration, 9.1 minutes).
Of these 26 patients with hypotension, 17 (65%)
died (P =.01). When the number of hypotensive
episodes increased from 1 to 2 or more, the odds
ratio for death increased from 2.1 to 8.1.
Forty-one patients (38%) had hypoxia, with an
average of 2.1 episodes per patient (mean duration,
8.7 minutes). Of these 41 patients with hypoxia,
18 (44%) died (P =.68). CONCLUSIONS: Hypotension,
but not hypoxia, occurring in the initial phase of
resuscitation is significantly (P =.009)
associated with increased mortality following
brain injury, even when episodes are relatively
short. These prospective data reinforce the need
for early continuous monitoring and improved
treatment of hypotension in brain-injured patients
|