Early N-terminal pro-B-type natriuretic peptide is associated with cardiac complications and function during pregnancy in congenital heart disease.

BACKGROUND: Elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels at 20 weeks' gestation predict adverse cardiovascular (CV) complications during pregnancy in women with congenital heart disease (CHD). To improve early risk assessment in these women, we investigated the predictive value of first-trimester NT-proBNP for CV complications and its association with ventricular function during pregnancy. METHODS: Pregnant women with CHD, previously enrolled in a prospective national study or evaluated by an identical protocol, were included. Clinical data, echocardiographic evaluation and NT-proBNP measurements were obtained at 12, 20 and 32 weeks' gestation. Elevated NT-proBNP was defined as > 235 pg/ml (95th percentile reference value of healthy pregnant women in the literature). RESULTS: We examined 126 females (mean age 29 years). Elevated NT-proBNP at 12 weeks was associated with CV complications (n = 7, 5.6%, odds ratio 10.9, p = 0.004). Arrhythmias were the most common complication (71%). The negative predictive value of low NT-proBNP to exclude CV complications was 97.2%. In women with CV complications, NT-proBNP levels remained high throughout pregnancy, while a decrease was seen in women without CV complications (p < 0.001 for interaction between group and time). At 12 weeks, higher NT-proBNP levels were associated with impaired subpulmonary ventricular function (p < 0.001) and also with a decline in subpulmonary ventricular function later in pregnancy (p = 0.012). CONCLUSIONS: In this study, first-trimester NT-proBNP levels were associated with adverse CV complications and a decline in subpulmonary ventricular function later in pregnancy in women with CHD. Early NT-proBNP evaluation is useful for tailored care in pregnant women with CHD.

Critical clue to ethylene glycol poisoning.

The authors report the case of a man 49 years of age with near-fatal ethylene glycol poisoning. Detection of calcium oxalate monohydrate crystals in the urine was the only real-time confirmation of the diagnosis. The case illustrates that, if the toxin has already been metabolized, familiarity with the appearance and significance of this unusual form of calcium oxalate crystal may be the key to an accurate diagnosis.

Practice guideline for arterial blood gas measurement in the intensive care unit decreases numbers and increases appropriateness of tests.

OBJECTIVE: To test the hypothesis that implementation of a practice guideline for blood gas measurement would decrease numbers and increase appropriateness of tests (according to criteria in the guideline) for up to 1 yr after introduction of the guideline. DESIGN: Numbers of tests and appropriateness of each test were measured retrospectively during each of five periods: two baseline periods 2 yrs and 1 yr before introduction of the guideline and three follow-up periods 2 to 3 months, 6 to 7 months, and 12 to 13 months after introduction of the guideline. SETTING: A ten-bed multidisciplinary intensive care unit (ICU) within a 500-bed tertiary teaching hospital. PATIENTS: A random sample of 30 patients admitted to the ICU during each of the periods specified above. INTERVENTIONS: The nominal group process was used to develop a new guideline and a multipronged educational approach was used to facilitate implementation of the guideline. MEASUREMENTS AND MAIN RESULTS: At 2 to 3 months, test numbers decreased from 4.9 +/- 1.6 to 3.1 +/- 1.8 (SD) tests/patient/day and to 2.4 +/- 1.2 tests/patient/day at 12 to 13 months. Appropriateness increased from a mean of 44% at baseline to 78% at 2 to 3 months and 79% at 12 to 13 months. There were no differences in Acute Physiology and Chronic Health Evaluation scores or ICU mortality among the patient groups and no differences in number of ventilator days or time to wean from ventilation. Cost-minimization analysis showed that the incremental cost-saving 1 yr after introduction of the guideline was $19.18 per patient per day. CONCLUSIONS: Implementation of this guideline for arterial blood gas measurement increases efficiency of test utilization without prolonging mechanical ventilation or affecting outcome.

Ethylene glycol poisoning: toxicokinetic and analytical factors affecting laboratory diagnosis.

Ethylene glycol poisoning is an important toxicological problem in medical practice because early diagnosis and treatment can prevent considerable morbidity and mortality. When ingested in the form of antifreeze or other automotive products, ethylene glycol results in central nervous system depression, cardiopulmonary compromise, and renal insufficiency. Metabolism of ethylene glycol to organic acids is required for metabolic derangement and organ damage. Laboratory features of ethylene glycol poisoning include increased anion gap metabolic acidosis, increased osmolal gap, calcium oxalate crystalluria, and detectable ethylene glycol in serum. This Case Conference integrates discussion of the toxicokinetic and analytical variables that affect the laboratory diagnosis of ethylene glycol intoxication.