Book Text

Vulnerable Patient Populations

Clinical trials of deliberate hypotensive resuscitation have restricted the application of this technique to populations perceived to be at greater risk for ischemic complications,^[73] ^[77] including patients with known ischemic coronary disease, elderly patients, and those with injuries to the brain or spinal cord. The prohibition against hypotension in patients with TBI is especially well established

TABLE 63-9 -- Differences in clinical findings in surgical patients undergoing elective deliberate hypotension and emergency trauma cases*

Aspect Elective Trauma

Intravascular volume Euvolemic Hypovolemic

Temperature Normal Probably hypothermic

Capillary beds Dilated Constricted

Level of general anesthesia Deep Usually light

Preexisting mental status Normal May be impaired

Coexisting injuries None May be significant

Comorbid conditions Known and managed Unknown

*Each of these factors produces a real or perceived contraindication to the use of a deliberate hypotensive technique in trauma patients.

**TABLE 63-9** -- Differences in clinical findings in surgical patients undergoing elective deliberate hypotension and emergency trauma cases*
Aspect	Elective	Trauma
Intravascular volume	Euvolemic	Hypovolemic
Temperature	Normal	Probably hypothermic
Capillary beds	Dilated	Constricted
Level of general anesthesia	Deep	Usually light
Preexisting mental status	Normal	May be impaired
Coexisting injuries	None	May be significant
Comorbid conditions	Known and managed	Unknown

**TABLE 63-10** -- Goals for early resuscitation*
Maintain systolic blood pressure at 80–100 mm Hg
Maintain hematocrit at 25%–30%
Maintain prothrombin time and partial thromboplastin time in normal ranges
Maintain platelet count >50,000
Maintain normal serum ionized calcium
Maintain core temperature >35°C
Maintain function of pulse oximeter
Prevent increase in serum lactate
Prevent acidosis from worsening

*Fluid administration to limit hypoperfusion is balanced against an undesirable increase in blood pressure and thus hemorrhage volume.

because of the observed disparity in outcome between TBI patients who experience hypotension and those who do not.^[78] ^[79] It is also well established that older trauma patients suffer worse outcomes from similar injuries, presumably because of their reduced physiologic reserve.^[80] Clinical care of these patients is focused on avoidance of ischemic stress and rapid correction of hypovolemia. It may well develop, however, that deliberate hypotensive management to enable rapid control of hemorrhage is equally beneficial in vulnerable populations. No clinical trials to date have investigated this subject, but one recently published laboratory study did find a benefit of deliberate hypotension in animals with both TBI and hemorrhagic shock.^[81] Absent convincing human evidence, the role for deliberate hypotension in older or brain-injured patients is likely to remain limited.