Neonatal-Perinatal Fellow University of California Davis University of California Davis Sacramento, California, United States
Background: The perinatal asphyxiated lamb model closely mimics the transitioning physiology of the sick newborn who requires resuscitation at birth. Near-infrared spectroscopy (NIRS) to measure cerebral regional saturation of oxygen (CrSO2) may be used as an adjunct to pulse oximeter oxygen saturation (SpO2) measurements in the delivery room to monitor response to resuscitation. No studies have assessed accuracy of NIRS during chest compressions.
Objective: To evaluate the reliability of NIRS during resuscitation in a perinatal asphyxiated cardiac arrest lamb model that closely mimics the transitioning physiology of the newly born infant.
Design/Methods: Twenty-three lambs were exteriorized, intubated and instrumented prior to cord occlusion. A pulse oximeter was placed on the right forelimb to measure SpO2 and a NIRS sensor was placed on the head to measure CrSO2. Cardiac arrest was induced by umbilical cord occlusion and lambs were resuscitated following NRP guidelines. Hemodynamic parameters were continuously recorded using data acquisition software. Arterial and venous blood gases were collected at fetal baseline, at asystole, at ROSC, every minute post-ROSC for 5 minutes, and at 10 minutes post-ROSC.
Results: All lambs achieved ROSC. The average weight (standard deviation) of the lambs was 3.93 kg (0.81) and the median time (interquartile range [IQR]) to asystole was 14 minutes (13.0, 17.2). Median time (IQR) to ROSC was 4.4 minutes (2.9, 5.3). Figure 1 shows the relationship between SpO2, CrSO2, SaO2, and SvO2 from asphyxia to 10 minutes post-ROSC. CrSO2 values quickly rise following ROSC along with a significant increase in oxygen delivery to the brain (figure 2). SpO2 appear unreliable during chest compressions and the first minute post-ROSC. Pearson correlation comparing brain oxygen delivery (DO2) to CrSO2, SaO2 and SpO2 were 0.56, 0.53, and 0.45, respectively. Correlation comparing arterial oxygen saturation (SaO2) to CrSO2 and SpO2 were 0.79 and 0.64, respectively. Partial pressure of arterial oxygen (PaO2) values were high following ROSC compared to the normal acceptable range in newly born infants (figure 3). Oxygen consumption (VO2) was markedly lower than DO2 postnatally (figure 4). Conclusion(s): In perinatal asphyxial cardiac arrest, NIRS measurements may be more sensitive than SpO2. CrSO2 can serve as a valuable adjunct to adjust FiO2 during and following resuscitation. Further studies are needed before implementation into clinical practice.
Authors/Institutions: Lida I. Zeinali, University of California Davis, Sacramento, California, United States; Morgan Hardie, University of California Davis, Sacramento, California, United States; Amy Lesneski, University of California Davis, Sacramento, California, United States; Deepika Sankaran, University of California Davis, Sacramento, California, United States; Satyan Lakshminrusimha, University of California Davis, Sacramento, California, United States; Payam Vali, University of California Davis, Sacramento, California, United States