The purpose of this experiment was to determine body fluid distribution during chronic cold exposure and to further understand the mechanism of cold-induced hypertension. Blood pressures, hematocrit, and the plasma, blood, and extracellular fluid volumes were measured in rats at intervals of 1, 3, and 5 weeks after exposure to cold (5 degrees C). Resting systolic, diastolic, and mean blood pressures measured by direct arterial cannula were significantly elevated in a time-dependent manner over the duration of cold exposure. The increase in diastolic blood pressure, which reflects the peripheral vascular resistance, exceeded that of systolic blood pressure after both 3 and 5 weeks of exposure to cold. Pulse pressure was significantly decreased by 3 and 5 weeks of cold exposure. The plasma, blood, and extracellular fluid volumes were significantly increased after both 1 and 3 weeks of exposure to cold, but had returned to control levels by 5 weeks of cold exposure. Cold exposure, however, did not affect the hematocrit. The 2-h water intake after the cold-exposed rats were returned to warm (25 degrees C) (thermogenic drinking) was significantly increased compared to that of warm-acclimated rats during the first, third, and fifth week of exposure to cold. The present results suggest that the development of cold-induced hypertension is associated with blood volume expansion, and that the elevated blood pressure is maintained by increased peripheral vascular resistance without blood volume expansion. The results also imply that exposure to cold induces a dehydration in rats.

Acclimatization↗

PubMedDate not supplied

Fractured neck of the femur (DRG 210/211): prospective outcome study.

BACKGROUND: An ageing population will increase the need for resources to treat patients with a fractured neck of femur (DRG 210/211). Provision of these resources will be helped by a better understanding of current practices. METHODS: A prospective study of outcome at discharge for 100 consecutive patients with DRG 210/211 was conducted at five Victorian metropolitan teaching hospitals to assess length of stay and the reasons for any variations. RESULTS: The major influences on timing of discharge were: delayed availability of rehabilitation beds; the timing of referral and assessment by the Geriatric Assessment Team; delay in surgery more than 24 h after admission; and development of postoperative complications. CONCLUSION: The efficient management of patients with DRG 210/211 requires a strong protocol of treatment and referral strategies with adequate resources.

Aged↗