Accuracy of Pulse Oximeter on Newborn Wrist and Ankle
Accuracy of Pulse Oximeter on Newborn Wrist and Ankle
This was a prospective observational study conducted at the level III neonatal intensive care unit (NICU) at Los Angeles County+University of Southern California Medical Center. The study population consisted of patients (gestational age 23 to 42 weeks) admitted to the NICU from July 2009 through March 2010. The study was approved by our Institutional Review Board and informed consent obtained from the parents. Infants with birth weight >4500 g and those with multiple congenital anomalies were excluded from the study.
The Masimo Radical-7 pulse oximeter (Masimo, Irvine, CA, USA) was used for this study. SpO2 data collection was carried out with two oximeters calibrated for the study for simultaneous paired SpO2 measurements. The mode with an averaging time of 8 s, which is the standard mode during routine clinical care in our NICU, was used. We measured the initial SpO2 detected at the palm and ipsilateral wrist first, then at 30 s, and at 1 min, and we repeated the same procedure over the sole and ipsilateral ankle. In addition, we recorded the time to obtain the SpO2 readings (response time) from all these sites. The value was considered only if the pulse oximeter pulse rate did not differ by more than three beats from the heart rate on the independent bedside monitor. In infants receiving phototherapy, the lights were temporarily turned off during these procedures. We also recorded demographic data including gestational age, birth weight, postnatal age, current weight, vital signs including body temperature, use of medications and hemoglobin at the time of study. A convenient sample of 150 infants was studied to include a representative group of patients with a gestational age of 23 to 42 weeks admitted to the NICU. For each patient, recordings were collected at baseline (initial pulse oximeter reading), at 30 s and at 1 min.
We used two-tailed, Student's t-tests for analysis of continuous, normally distributed variables. Regression analysis was performed to determine the relationship between paired SpO2 measurements. In addition, the mean and standard deviation of the paired SpO2 differences (bias and precision) were calculated using Bland–Altman analysis. Values are presented as mean±s.d., unless otherwise indicated. Statistical significance was set at P<0.05 for all tests.
Methods
This was a prospective observational study conducted at the level III neonatal intensive care unit (NICU) at Los Angeles County+University of Southern California Medical Center. The study population consisted of patients (gestational age 23 to 42 weeks) admitted to the NICU from July 2009 through March 2010. The study was approved by our Institutional Review Board and informed consent obtained from the parents. Infants with birth weight >4500 g and those with multiple congenital anomalies were excluded from the study.
The Masimo Radical-7 pulse oximeter (Masimo, Irvine, CA, USA) was used for this study. SpO2 data collection was carried out with two oximeters calibrated for the study for simultaneous paired SpO2 measurements. The mode with an averaging time of 8 s, which is the standard mode during routine clinical care in our NICU, was used. We measured the initial SpO2 detected at the palm and ipsilateral wrist first, then at 30 s, and at 1 min, and we repeated the same procedure over the sole and ipsilateral ankle. In addition, we recorded the time to obtain the SpO2 readings (response time) from all these sites. The value was considered only if the pulse oximeter pulse rate did not differ by more than three beats from the heart rate on the independent bedside monitor. In infants receiving phototherapy, the lights were temporarily turned off during these procedures. We also recorded demographic data including gestational age, birth weight, postnatal age, current weight, vital signs including body temperature, use of medications and hemoglobin at the time of study. A convenient sample of 150 infants was studied to include a representative group of patients with a gestational age of 23 to 42 weeks admitted to the NICU. For each patient, recordings were collected at baseline (initial pulse oximeter reading), at 30 s and at 1 min.
Statistical Analysis
We used two-tailed, Student's t-tests for analysis of continuous, normally distributed variables. Regression analysis was performed to determine the relationship between paired SpO2 measurements. In addition, the mean and standard deviation of the paired SpO2 differences (bias and precision) were calculated using Bland–Altman analysis. Values are presented as mean±s.d., unless otherwise indicated. Statistical significance was set at P<0.05 for all tests.