[Reactive increase in blood pressure on immobilization, but not hypertension, prevents pressure ulcers]

Of 135 geriatric patients immobilized for at least 2 days, 37 (27.4%) had pressure ulcers (PU). Those without PU were the control comparison group. Gender, length of immobilization, number of blood pressure determinations and proportion with hypertension were similar in those with and without PU. Those with PU were slightly older than those in the comparison group: 75.5 +/- 8.8 and 74.7 +/- 9.6 years, respectively (p > 0.05). Of 66 patients with acute ischemic stroke, reactive increase of systolic or diastolic blood pressure to 140/90 mm Hg or above following immobilization, was seen in 60.6% and 22.7% of patients, respectively, and there were PU in 12.1%. Of 17 with recurrent ischemic stroke, corresponding figures were: 41.2%, 23.5% (p > 0.05), and 47.1% (p < 0.01). In 7 patients with previous ischemic stroke corresponding figures were: 14.3% and 0% (p < 0.01) and 100% (p < 0.001). In 36 operated for fracture of the femur, corresponding figures were: 50%, 11.1% (p > 0.05), and 27.8% (p > 0.05). For 9 patients with severe infections, sepsis or pneumonia, the corresponding figures were: 22.2% and 0.0% (p > 0.05), and 44.4% (p < 0.04). The proportion of patients with reactive increase in systolic blood pressure on immobilization was lower in the PU group than in the controls, 27% vs 59.2%, (p < 0.001). The corresponding figures for reactive increase in diastolic blood pressure were similar, 8.1% and 20.4%, respectively (p > 0.05). The mean systolic blood pressure on immobilization was higher in the control than in the PU group, 145.4 +/- 21.7 and 130.8 +/- 14.9 mm Hg, respectively (p < 0.001). The corresponding figures for the mean diastolic blood pressure were similar, 81.2 +/- 10.5 and 75.7 +/- 8.9 mm Hg, respectively (p < 0.01). An increase in systolic blood pressure on immobilization reduced the risk of developing PU (p < 0.05). There was no significant statistical relation between diagnosis of hypertension and proportion of patients with PU (p > 0.05). Of 67 patients with hypertension, in 23.9% and 74.6% of them there was no increase in systolic or diastolic blood pressure, respectively. Statistical difference between lack of diastolic or systolic response was very significant (p < 0.001). Reactive increase of blood pressure, but not hypertension, predicts reduced risk of PU on immobilization in the hospitalized elderly. Diminished reactive increase of blood pressure in response to stress of any kind may be a criterion of frailty and reduced physiological reserves. Efforts to reduce elevated blood pressure when a patient is immobilized appear irrational.