The effects of infusion rate on platelet outcomes and patient responses in children with cancer: an in vitro and in vivo study.

PURPOSE/OBJECTIVES: To determine the influence of infusion rate on quality of transfused platelets and patients' physical and subjective responses. DESIGN: Linked in vitro and in vivo studies with repeated measures and crossover designs, respectively. SETTING: A 52-bed pediatric cancer center in the midsouthern United States. SAMPLE: In vitro: 12 randomly selected platelet units. in vivo: convenience sample of 26 children, ages 3-20 years, with cancer and thrombocytopenia requiring platelet transfusion. METHODS: Four infusion rates studied in vitro: two infusion rates studied in vivo. MAIN RESEARCH VARIABLES: Platelet count, morphology score, corrected count increment, and patients' physical and subjective responses. FINDINGS: No clinically significant differences were found in outcomes across the four rates in vitro. Similarly, no statistically significant differences were found between the two in vivo rates on objective or subjective outcomes. CONCLUSIONS: In this setting, the more rapid infusion rate is clinically preferable because it does not negatively affect platelet recovery or patient outcomes and it decreases the infusion time by half. IMPLICATIONS FOR NURSING PRACTICE: Findings provided a basis for altering platelet infusion rates at the study setting. Benefits of the faster infusion rate include more rapid correction of thrombocytopenia, decreased time that outpatients must remain in the clinic for transfusion. Increased time available for other parenteral infusions in the impatient setting, and substantial savings in nursing time and associated costs.

The effects of infusion methods on platelet count, morphology, and corrected count increment in children with cancer: in vitro and in vivo studies.

PURPOSE/OBJECTIVES: To determine whether infusion method influences the quality of platelets transfused. DESIGN: Linked in vitro and in vivo study. Quasi-experimental design for in vitro and cross-over design with balanced randomization for in vivo. SETTING: Pediatric cancer center in the midsouthern United States. SAMPLE: Pheresed/pooled platelet units in vitro (n = 12). In vivo convenience sample of 26 children, ages 2-19 years, with cancer and thrombocytopenia who required platelet transfusion. METHODS: Two infusion pumps (IMED 980 and Gemini, IMED Corp., San Diego, CA) versus gravity flow for in vitro platelet infusion. Gemini infusion pump versus gravity flow for in vivo platelet transfusion. MAIN OUTCOME MEASURES: Platelet count, morphology score, and corrected count increment. FINDINGS: No significant differences noted in platelet count or morphology score among or across the three infusion methods in vitro. No significant differences noted between the two infusion methods in platelet count or corrected count increment in vivo. CONCLUSIONS: Although limited to a specific patient population, setting, and infusion device, findings revealed that the pump was clinically acceptable because it did not negatively affect platelet recovery. Replication of this study with other infusion devices is recommended. IMPLICATIONS FOR NURSING PRACTICE: Study findings validate the current nursing procedure for the administration of platelets at the study setting. Use of infusion pumps for platelet transfusions is time-efficient and energy-efficient for nurses because the pumps offer a well-controlled infusion rate, accurate volume measurement, and an alarm system for monitoring the infusion.

Beneficial effect of brief pre-transfusion incubation of platelets at 37 degrees C.

The effects of brief warming of stored platelet concentrates were assessed in 15 children undergoing transfusion for stable thrombocytopenia due to chemotherapy (n = 13) or aplastic anaemia. Half of a pool of platelet concentrates stored at 22 degrees C was incubated at 37 degrees C for 1 hour and the other half at room temperature. Each patient received one bag of warmed and one of unwarmed cells transfused in random order 2 h apart. Platelet warming improved transfusion efficacy, as assessed on the basis of corrected platelet count increments (CCIs) and platelet morphology. Compared with unwarmed bags, warmed bags had a higher morphology score (p = 0.0001) and a higher CCI (adjusted for the transfusion order) at 1 h (n = 11; p = 0.014) and at 2 h (n = 15, p = 0.006) post transfusion. Thus, with platelets stored at room temperature bags warmed before transfusion to 37 degrees C for 1 h provide a larger number of circulating platelets after transfusion than do unwarmed bags.

Effects of prazosin and labetalol on blood pressure control and blood lipid levels in patients with mild-to-moderate essential hypertension.

Twenty hypertensive patients entered a crossover, placebo-controlled study of prazosin and labetalol that was designed to compare treatment effects on blood pressure control and lipid parameters. Both drugs significantly reduced sitting and standing systolic and diastolic blood pressures (p less than or equal to 0.01). No significant differences were noted between treatment groups in total cholesterol, high-density lipoprotein cholesterol, or very low-density lipoprotein cholesterol levels. However, a trend toward an increase in low-density lipoprotein cholesterol levels was seen during therapy with labetalol, whereas in contrast, no such effect was seen during treatment with prazosin.

Cardiac shape and function in aortic valve disease: physiologic and clinical implications.

Left ventricular shape and function were studied in 12 normal subjects, 18 patients with pressure overloading secondary to isolated aortic stenosis and 20 patients with volume overloading due to aortic regurgitation. End-diastolic volumes were mildly increased in aortic stenosis but greatly increased in aortic regurgitation. Average ejection fractions were normal in aortic stenosis but depressed in aortic regurgitation. Ventricular shape (eccentricity), normal (elongated) in nearly all patients with aortic stenosis, showed in diastole various degrees of abnormal roundness in patients with aortic regurgitation. As ventricular function declined in aortic regurgitation, the ventricles also became more round in systole. After valve surgery, clinical results were generally better in patients with aortic stenosis than in patients with aortic regurgitation. Among the latter, changes in eccentricity and ejection fraction were the best predictors of surgical outcome. It is postulated that chronic volume loading, as exemplified by aortic regurgitation, may induce basic alterations in architecture and fiber alignment of the left ventricular wall. Such changes may exert significant influence on the clinical course of these patients.