RESUMEN
We noticed that arterial oxygen saturation by pulse oximetry (SpO2) was generally lower when determined by the Ohmeda Biox 3700 pulse oximeter than when determined by the Nellcor N-100 pulse oximeter, and we investigated whether this finding was consistent and the reason for the discrepancy. We placed both oximeters simultaneously on 30 infants with indwelling arterial catheters and measured arterial partial pressure of oxygen (PaO2), percentage of fetal hemoglobin, and complete cooximetry, including arterial oxygen saturation (SaO2) with a Radiometer OSM-3 cooximeter, with and without correction for fetal hemoglobin levels, in four samples of blood from each infant during a 12-hour period for a total of 120 samples. The Nellcor SpO2 was consistently higher than the Ohmeda SpO2 by a mean (+/- SD) of 1.61% +/- 2.69% (p < 0.001). The Nellcor SpO2 correlated best with functional SaO2 (oxyhemoglobin (HbO2)/(HbO2 + reduced hemoglobin)) x 100); Ohmeda SpO2 correlated best with fractional SaO2 (HbO2/(HbO2 + reduced hemoglobin + carboxyhemoglobin + methemoglobin)) x 100), reflecting a fundamental difference in the calibration algorithms used in the two instruments. A desired PaO2 of 50 to 100 mm Hg, is maintained when the range of SpO2 is 90% to 96% for Ohmeda SpO2 and 92% to 98% for Nellcor SpO2 in the neonate, giving a positive predictive value in this study of 94% to 95%. We conclude that SpO2 determined by pulse oximeters of different brands is not interchangeable, and this may be of clinical importance in predicting PaO2 on the basis of SpO2.
Asunto(s)
Recién Nacido/sangre , Oximetría/instrumentación , Oxígeno/sangre , Cateterismo Periférico , Hemoglobina Fetal/análisis , Humanos , Oximetría/normas , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Arterias Tibiales , Arterias UmbilicalesRESUMEN
We reviewed erythrocyte transfusions, given after 2 weeks of age to premature infants, to derive patient selection criteria for trials of administration of recombinant human erythropoietin to maintain hematocrit during the anemia of prematurity. We first studied 122 infants, less than 36 weeks of gestational age, who remained in a level 3 nursery longer than 4 weeks. Multiple logistic regression analysis was used to select those variables associated with more than two transfusions after the second week; these included gestational age, 5-minute Apgar score, transfusion during the first week, and patent ductus ligation. The best predictor, alone or combined, was gestational age less than 30 weeks. This predictor was applied to a second population of 44 premature infants from a level 2 nursery, and we found a 94% probability of excluding those infants who did not receive a transfusion. This information will allow selection of premature infants who are candidates for administration of recombinant human erythropoietin.
Asunto(s)
Anemia/terapia , Transfusión Sanguínea , Recien Nacido Prematuro/sangre , Puntaje de Apgar , Transfusión Sanguínea/estadística & datos numéricos , Femenino , Edad Gestacional , Hematócrito , Humanos , Recién Nacido , Enfermedades Pulmonares/complicaciones , Masculino , Probabilidad , Factores de Riesgo , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
Fifty patients were compared for the purpose of investigating the usefulness of intrauterine resuscitation with tocolysis (IURT). Terbutaline was given, as an intravenous bolus, to 31 women in labor in whom fetal distress was diagnosed and urgent delivery by cesarean section was indicated. In alternate months, a control group of 19 women with similar diagnoses was urgently delivered after standard interventions such as maternal positioning, oxygen administration, hydration, and discontinuation of oxytocin. Improvement in perinatal outcome was shown in infants after IURT. Apgar scores were less than 7 in 42% of the study group and in 71% of the control group at 1 minute (P = .04). Five-minute Apgar scores less than 7 occurred in 7% of the study group and 24% of the control group. A low venous pH was seen in 55% of the control group compared with 29% of the infants resuscitated with terbutaline. Estimated maternal blood loss and hematocrit change was not different in the two groups. Maternal blood pressure and pulse changes following IURT were modest and of doubtful significance. We conclude that intravenous terbutaline administered as a bolus injection at the time of fetal distress in labor improves infant outcome as evidenced by more vigorous Apgar scores and less acidemia without significant adverse physiologic effects on the mother.