Biomedical subjects

I A Zabaleta

Publications and source records attributed to I A Zabaleta.

3 recordsLinked to original sources

PubMed1995

A computer algorithm for differentiating valid from distorted pulse oximeter waveforms in neonates.

Current pulse oximeter technology is fraught with a significant false alarm rate. This is mainly due to motion artifacts at the sensor site which distort the pulse waveform and render the computation of SaO2 invalid. If the pulse waveform could be automatically recognized as either normal or distorted, then only valid SaO2 values would be displayed. We observed that the systolic upstroke time (Sy) of the pulse waveform has a narrow and consistent range in normal appearing pulses. The systolic upstroke time (Sy) is the time from the onset of systole to the peak of the pulse waveform. Comparison of a preset range of Sy was made against Sy obtained by computer analysis of each pulse waveform. Visual examination of 14,090 pulses was carried out to determine the sensitivity and false positive rate of the algorithm. Sensitivity of computer detection of valid pulses was 92% with a positive predictive value of 92%. When used on line for continuous recording of SaO2 in patients, this simple algorithm has the potential to decrease the false alarm rate of pulse oximeters and improve the accuracy of long-term SaO2 recordings.

Algorithms↗

PubMed1995

Diaphragmatic flutter in three babies with bronchopulmonary dysplasia and respiratory syncytial virus bronchiolitis.

Abnormalities of respiratory control, especially apnea, have been reported previously in infants with respiratory syncytial virus (RSV) infections. This is the first report of yet another abnormality of respiratory control, diaphragmatic flutter (DF), in infants with RSV infection. The presentation of these infants did not differ from the usual clinical presentation of RSV infection. While being monitored with respiratory inductive plethysmography for occurrences of apnea known to be common in RSV infection, DF was detected. This abnormality consisted of high frequency, diaphragmatic contractions which were intermittent in nature. They lasted no more than 4 days and were not associated with change in arterial oxygen saturation or heart rate. These infants were discharged free of DF and no further episodes have been observed over a 12-month period.

Administration, Inhalation↗

PubMed1994

Comparison of supine and prone noninvasive measurements of breathing patterns in fullterm newborns.

The current study was undertaken to ascertain whether shift from supine to prone posture alters the pattern of natural breathing in healthy fullterm newborns. Breathing patterns were measured in the supine and prone posture in 20 healthy fullterm infants using calibrated, noninvasive respiratory inductive plethysmography (RIP). The values for breathing pattern components in supine and prone postures expressed as means (+/- SD) were, respectively, tidal volume (VT), 14.1(+/- 3.2) and 18.9(+/- 4.9)mL; mean inspiratory flow 26.7(+/- 11.5) and 32.8(+/- 13.0)mL/s; and minute ventilation 232(+/- 75) and 288(+/- 96)mL/kg/min (P < 0.01). Less thoracoabdominal incoordination, expressed as the labored breathing index (LBI), occurred with shift from supine to prone posture in infants studied in the active behavioral stage, changing from 2.0(+/- 0.5) to 1.3(+/- 0.4) (P < 0.01). Placement of a facemask-pneumotachograph system increased VT measured with RIP by 26% in the supine, and 18% in the prone posture. Neither respiratory rate nor inspiratory time (Ti) changed with the postural shift. Therefore, change from supine to prone posture improved ventilation and increased respiratory drive as expressed by VT/Ti. Further, thoracoabdominal incoordination which took place during active sleep in the supine posture, lessened with change to the prone posture.

Humans↗