D van Stralen | PubMed Health

PubMed1985

A practical heparin reduction algorithm: execution and operational characteristics.

A limited pilot study has been made of a newly devised heparin reduction algorithm (HRA). This formulation is a derivative of the alternative surveillance plan known as the activated partial thromboplastin time after heparin removal (aPTT/HR) scheme. Unlike the traditional plan, the HRA is the first approach to provide information about the individual and collective pharmacological effects of heparin and coumarins when the drugs are administered simultaneously. In this feasibility study the HRA was used without incident in six patients every 24 h to calculate the trend of the evolving anticoagulant effect of coumarin. The computations provided by a laboratory based data management group permitted the clinician to titrate precisely the withdrawal of heparin in response to the daily fluctuations in coumarin effect. In this way, the activated partial thromboplastin time could always be maintained within the desired therapeutic interval. Three divergent patient experiences are presented to demonstrate the operational characteristics and responsiveness of the new HRA plan.

Adult↗

PubMedDate not supplied

CBF and CBF/PCO2 reactivity in childhood strangulation.

Four children with self-inflicted strangulation injuries had cerebral blood flow determined by stable xenon computed tomography (XeCTCBF) within 24 hours of admission. All had suffered a severe hypoxic-ischemic cerebral injury; 3 initially had fixed pupils, all were apneic with varying bradyarrhythmias, and the initial mean arterial pH was 7.26 (+/- 0.18). The initial blood glucose values were greater than 300 mg/dl (334 and 351 mg/dl) in the 2 patients who died compared to the 2 who survived (104 and 295 mg/dl). The cardiac index was depressed during the first several days of hospitalization in the 2 patients who died (less than 2.0 L/min/m2) compared to the 2 who survived. Total CBF was normal (63 +/- 8 ml/min/100 gm) and local variations in CBF were present. PCO2 reactivity was determined by hyperventilating the 4 patients for 20 min from an end tidal PCO2 of 39 +/- 3 torr to 29 +/- 1 torr and then repeating the XeCTCBF study. Marked regional variability in the CBF/PCO2 response was observed, ranging from 0.5-5.5 ml/min/100 gm/torr PCO2. In the 2 patients who died, the CBF/PCO2 was decreased (1.2 ml/min/100 gm/torr PCO2) compared to the 2 patients who survived (2.1 ml/min/100 gm/torr PCO2). Although CBF was normal in these 4 children, the hyperventilation response was depressed, variable, and even paradoxical which may be important in the evolution of further brain injury and is a critical factor in deciding whether hyperventilation may be of clinical benefit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗