Pharmacokinetic and pharmacodynamic monitoring of the elderly in critical care.

The cases presented illustrate the clinical application of several of the common pharmacokinetic and pharmacodynamic changes in the elderly. The number of drugs that must be used with caution in the aging person is potentially quite large. In addition, there are numerous other diseases that can result in additional changes in drug absorption, distribution, metabolism, excretion, and target-organ effect. These conditions are particularly prevalent in the elderly patient in the critical care setting, and include the systemic inflammatory response syndrome, sepsis, acute renal failure, diabetic ketoacidosis, and the postoperative state. It must be emphasized, however, that the elderly are not a homogeneous group. The rate of decline of many physiologic functions varies widely. Chronic diseases and lifestyle alterations are additional variables that affect the function of many body systems. Furthermore, it is likely that the different pharmacokinetic and pharmacodynamic parameters discussed in this article do not all change to the same degree in a given individual. Pharmacologic therapy, therefore, always will be quite empiric in elderly patients. There is no substitute for meticulous monitoring of the patient using every available modality. This is particularly crucial in the critical care setting, where drugs can be lifesaving and life threatening at the same time.

Transient ST elevation associated with tension pneumothorax.

In a 52-year-old man, a spontaneous right tension pneumothorax was associated with transient bradycardia, hypotension and electrocardiogram (ECG) changes consisting of precordial ST elevation suggestive of acute myocardial injury. Immediately after chest tube placement, the ECG reverted to near normal. Serial cardiac enzymes and isoenzymes showed no evidence of myocardial infarction. To our knowledge, this is the first reported case of this association. The ECG changes may be related to the hypotensive state induced by the tension pneumothorax with resulting decreased coronary artery blood flow and myocardial ischemia that resolved without infarction.

Algorithm-directed triage in an emergency department.

At Brooke Army Medical Center the Emergency Services Section has developed an algorith,-directed triage system to be used by "screeners" who may be basic medical corpsmen but sometimes have had no previous medical experience. After 25 hours of classroom and 120 hours of on-the-job training, the screeners use the algorithms to triage patients into one of three treatment areas in the emergency section or to clinics outside the emergency section during the day and evening. The screeners may consult with a triage physician if the algorithm-directed disposition appears inappropriate, Triage dispositions of 78,822 patient visits during the calendar year 1975 are presented.