Utilization of osmometry in critically ill surgical patients

Plasma osmolality, osmoregulation and prognosis after head injury

108 Patients with severe brain damage were examined for the course of plasma osmolality. In addition plasma values of Na+, K+, glucose and blood urea nitrogen (BUN) were measured simultaneously by auto-analyzer. The clinical status was registered daily by using a modified Glasgow coma scale. Outcome of the injured patients was registered by using the Glasgow outcome scale. 60 patients survived, 48 died, 39 of brain damage and 9 of secondary diseases, such as infection or embolism. Sustained severe brain damage is generally followed by disturbances of metabolic regulation. Quite often the osmotic regulation is disturbed. In most cases these disturbances are of hyperosmolar nature, their extent and duration being correlated to the prognosis. Hyposmolar deregulation occurs less frequently, and occasionally lead to peracute brain oedema (e.g. SIADH-syndrome). These dysregulations are interpreted as disturbances of the central function of the diencephalon, in lethal cases even as "hypothalamic death". Blood osmolality measurements should therefore be made early in states of acute cerebral disease to help establish a prognosis, control the treatment of water imbalance and to determine contra-indications to osmotherapy.

The effect of hemorrhage and resuscitation on serum levels of immunoreactive atrial natriuretic factor

To determine if atrial natriuretic factor (ANF) might have a role in blood volume regulation during hypovolemia, the serum level was measured before and after hemorrhage and resuscitation (RESUS) in a porcine shock model. Hemorrhage of 40% of the blood volume produced significant (p less than 0.01) decreases in mean arterial pressure, central venous pressure, and cardiac output and a significant increase in heart rate (HR), plasma renin activity, and catecholamines (p less than 0.01). Hemorrhage was also associated with a significant increase in ANF (p less than 0.05). All parameters except HR returned to baseline values with RESUS. The rise in ANF associated with moderate hemorrhage was unexpected, but may have been due to the profound tachycardia or decreased degradation during shock. Sodium excretion and urine flow increased significantly with RESUS without an associated increase in ANF, suggesting that ANF may not be involved in the early phase of postresuscitation diuresis.

Alcohol intoxication and serum osmolality

The relation between serum osmolality and blood-alcohol was studied prospectively in 565 acute trauma patients. The two measurements were closely correlated. It is therefore possible to estimate the blood-alcohol from serum osmolality to assist in the clinical management of acutely injured patients.

Newer Techniques in evaluation of injured patients

Effective management of the severely injured requires an experienced, knowledgeable, and thoughtful physician who has a rational approach to both evaluation and treatment firmly in mind. When in doubt, access to a Trauma Registry (computerized) can be exceedingly valuable to assist in selecting the most effective treatment for a given clinical problem. The evaluation of the patient centers about general metabolic considerations, including acid-base disequilibrium, respiratory insufficiency, fluid volume monitoring, tissue perfusion (urine output), and osmolality. Diagnostic efforts to identify organ injury include infusion pyelography, paracentesis, radionuclide scanning, and angiography. The most critical diagnostic evaluation, however, remains frequent, careful examination of the injured patient, meticulously noting and interpreting all changes in physical findings.