Correlation of blood volume values and pulmonary artery catheter measurements

To correlate the values generated by direct total blood volume measurement with pulmonary artery catheter parameters and commonly used laboratory values in the management of critically ill patients. This study was carried out at the Lutheran Medical Center, Brooklyn, New York, United States of America, during the period 1998-1999. We prospectively correlated the total blood volume [TBV] values generated by the blood volume analyzer [BVA]-100 using I131-tagged albumin, with the values obtained from pulmonary artery catheter [PAC] of central venous pressure, pulmonary capillary wedge pressure, cardiac output, and with laboratory values of hematocrit, lactate, arterial blood gas and mixed venous blood, in critically ill patients. Twenty-four intensive care unit [ICU] patients were studied. Inclusion criteria: Admission to the intensive care, pulmonary artery catheter insertion and [APACHE] II Acute Physiology and Chronic Health Evaluation score of 8-30 [mean=17.875]. Exclusion criteria: Pediatric patients, hemodynamically normal or stable patients, pregnancy, and critically ill patients that were managed in an ICU setting without PAC catheter. Height and weight were recorded. After the collection of an initial blood sample [5cc], one cc of I131-tagged albumin [15-25 microcuries] was injected using a patented syringe. Five venous samples were collected after the isotope injection. The collection times were entered into the BVA-100. Hematocrit measurements were performed in duplicate. Blood samples were centrifuged and one ml from the plasma of each sample was pipetted [in duplicate] into the sample tube then placed into the BVA-100. The results showed that the TBV did not correlate with either pulmonary capillary wedge pressure or central venous pressure, and except for the cardiac output, there is no correlation between pulmonary capillary wedge pressure readings or TBV results and the other parameters considered in this study. This method can be released from the research fields and can be safely incorporated into the clinical arena. It provides an accurate assessment of the volume status in intensive care unit patients

Hypocalcemia in the critically ill child

This study was carried out on 39 critically ill infants and children at the New Children's Hospital of Cairo Univeristy to detect the frequency of hypocalcemia and derangements in calcium homeostasis among the critically ill children. The children were grouped into four groups; cardiac, respiratory, neurological and renal, with 10 normal infants and children as a control group. Determination of total serum calcium, serum ionized calcium, arterial blood pH and serum albumin were done. Results showed that total serum calcium was in all groups, serum ionized calcium was significantly lower in all groups except the neurological one, albumin was low in the renal group only, arterial pH was different from the control group in all other groups except the cardiac one. It was also observed that decreased serum albumin leads to decreased total calcium, increased pH leads to decrease ionized calcium and vice versa. Correlation between total and ionized calcium showed a +ve significant correlation in all groups except the renal group. Therefore, it is indicated that hypocalcemia is a common, unrecognized problem in the critically ill pediatric patient. The total serum calcium concentration is a poor predictor for those patients while serum ionized calcium value is a better predictor for the more clinically relevant cases. For that reason, it is recommended to measure serum ionized calcium in critically ill children and consequently calcium administration, specially in those suffering from multisystem derangements, even if the total serum calcium is within normal value