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Featured researches published by Payam Vali.


Neonatology | 2012

Ultrasound Confirmation of Endotracheal Tube Position in Neonates

Debra Dennington; Payam Vali; Neil N. Finer; Jae H. Kim

Background: The placement of the endotracheal tube (ETT) in neonates is a challenging procedure that currently requires timely confirmation of tip placement by radiographic imaging. Objective: We sought to determine if bedside ultrasound (US) could demonstrate ETT tip location in preterm and term newborns and offer a quick alternative method of ETT positioning. Methods: We conducted a prospective pilot study of 30 newborns admitted to the UC San Diego Medical Center who had their ETT placement confirmed by chest radiographs. After a radiograph, each infant had a US exam with a 13-MHz linear transducer on a portable US machine. To assist localization, gentle longitudinal movement of the ETT of less than 0.5 cm was performed. Measurements from the tip of the ETT tip to the carina were made on chest radiograph and midsagittal US images. Results: Study infants had a mean gestational age of 30.2 ± 4.9 (SD) weeks and mean birth weight of 1,595.2 ± 862 g. US images were taken a mean 2.9 ± 2.2 h after radiographs. Data from 2 infants were excluded for poor radiograph image quality and extreme outlier values. The ETT was visualized by US in all newborns examined. We observed a good correlation between ETT tip-to-carina distance on US and radiograph (r2 = 0.68) with minimal bias. Each study took less than 5 min to obtain without any clinical deterioration. Conclusions: Bedside US can visualize the anatomic position of the ETT position in preterm and term infants but further validation is required before routine clinical implementation.


Maternal Health, Neonatology and Perinatology | 2015

Neonatal resuscitation: evolving strategies

Payam Vali; Bobby Mathew; Satyan Lakshminrusimha

Birth asphyxia accounts for about 23% of the approximately 4 million neonatal deaths each year worldwide (Black et al., Lancet, 2010, 375(9730):1969-87). The majority of newborn infants require little assistance to undergo physiologic transition at birth and adapt to extrauterine life. Approximately 10% of infants require some assistance to establish regular respirations at birth. Less than 1% need extensive resuscitative measures such as chest compressions and approximately 0.06% require epinephrine (Wyllie et al. Resuscitation, 2010, 81 Suppl 1:e260–e287). Transition at birth is mediated by significant changes in circulatory and respiratory physiology. Ongoing research in the field of neonatal resuscitation has expanded our understanding of neonatal physiology enabling the implementation of improved recommendations and guidelines on how to best approach newborns in need for intervention at birth. Many of these recommendations are extrapolated from animal models and clinical trials in adults. There are many outstanding controversial issues in neonatal resuscitation that need to be addressed. This article provides a comprehensive and critical literature review on the most relevant and current research pertaining to evolving new strategies in neonatal resuscitation. The key elements to a successful neonatal resuscitation include ventilation of the lungs while minimizing injury, the judicious use of oxygen to improve pulmonary blood flow, circulatory support with chest compressions, and vasopressors and volume that would hasten return of spontaneous circulation. Several exciting new avenues in neonatal resuscitation such as delayed cord clamping, sustained inflation breaths, and alternate vasopressor agents are briefly discussed. Finally, efforts to improve resuscitative efforts in developing countries through education of basic steps of neonatal resuscitation are likely to decrease birth asphyxia and neonatal mortality.


Journal of the American Heart Association | 2017

Evaluation of Timing and Route of Epinephrine in a Neonatal Model of Asphyxial Arrest.

Payam Vali; Praveen Chandrasekharan; Munmun Rawat; Sylvia F. Gugino; Carmon Koenigsknecht; Justin Helman; William J. Jusko; Bobby Mathew; Sara K. Berkelhamer; Jayasree Nair; Myra H. Wyckoff; Satyan Lakshminrusimha

Background Epinephrine administered by low umbilical venous catheter (UVC) or endotracheal tube (ETT) is indicated in neonates who fail to respond to positive pressure ventilation and chest compressions at birth. Pharmacokinetics of ETT epinephrine via fluid‐filled lungs or UVC epinephrine in the presence of fetal shunts is unknown. We hypothesized that epinephrine administered by ETT or low UVC results in plasma epinephrine concentrations and rates of return of spontaneous circulation (ROSC) similar to right atrial (RA) epinephrine. Methods and Results Forty‐four lambs were randomized into the following groups: RA epinephrine (0.03 mg/kg), low UVC epinephrine (0.03 mg/kg), postcompression ETT epinephrine (0.1 mg/kg), and precompression ETT epinephrine (0.1 mg/kg). Asystole was induced by umbilical cord occlusion. Resuscitation was initiated following 5 minutes of asystole. Thirty‐eight of 44 lambs achieved ROSC (10/11, 9/11, and 12/22 in the RA, UVC, and ETT groups, respectively; subsequent RA epinephrine resulted in a total ROSC of 19/22 in the ETT groups). Median time (interquartile range) to achieve ROSC was significantly longer in the ETT group (including those that received RA epinephrine) compared to the intravenous group (4.5 [2.9–7.4] versus 2 [1.9–3] minutes; P=0.02). RA and low UVC epinephrine administration achieved comparable peak plasma epinephrine concentrations (470±250 versus 450±190 ng/mL) by 1 minute compared to ETT values of 130±60 ng/mL at 5 minutes; P=0.03. Following ROSC with ETT epinephrine alone, there was a delayed peak epinephrine concentration (652±240 ng/mL). Conclusions The absorption of ETT epinephrine is low and delayed at birth. RA and low UVC epinephrine rapidly achieve high plasma concentrations resulting in ROSC.


Neonatology | 2016

Continuous End-Tidal Carbon Dioxide Monitoring during Resuscitation of Asphyxiated Term Lambs.

Praveen Chandrasekharan; Munmun Rawat; Jayasree Nair; Sylvia F. Gugino; Carmon Koenigsknecht; Daniel D. Swartz; Payam Vali; Bobby Mathew; Satyan Lakshminrusimha

Background: The Neonatal Resuscitation Program (NRP) recommends close monitoring of oxygenation during the resuscitation of newborns using a pulse oximeter. However, there are no guidelines for monitoring carbon dioxide (CO2) to assess ventilation. Considering that cerebral blood flow (CBF) correlates directly with PaCO2, continuous capnography monitoring of end-tidal CO2 (ETCO2) may limit fluctuations in PaCO2 and, therefore, CBF during resuscitation of asphyxiated infants. Objective: To evaluate whether continuous monitoring of ETCO2 with capnography during resuscitation of asphyxiated term lambs with meconium aspiration will prevent fluctuations in PaCO2 and carotid arterial blood flow (CABF). Methods: Fifty-four asphyxiated term lambs with meconium aspiration syndrome were mechanically ventilated from birth to 60 min of age. Ventilatory parameters were adjusted based on clinical observation (chest excursion) and frequent arterial blood gas analysis in 24 lambs (control group) and 30 lambs (capnography group) received additional continuous ETCO2 monitoring. Left CABF was monitored. We aimed to maintain PaCO2 between 35 and 50 mm Hg and ETCO2 between 30 and 45 mm Hg. Results: There was a significant correlation between ETCO2 and PaCO2 (R = 0.7, p < 0.001), between PaCO2 and carotid flow (R = 0.52, p < 0.001) and between ETCO2 and carotid flow (R = 0.5, p < 0.001). PaCO2 and CABF during the first 60 min of age showed significantly higher fluctuation in the control group compared to the capnography group. Conclusion: Continuous monitoring of ETCO2 using capnography with mechanical ventilation during and after resuscitation in asphyxiated term lambs with meconium aspiration limits fluctuations in PaCO2 and CABF and may potentially limit brain injury.


Pediatric Research | 2017

Continuous capnography monitoring during resuscitation in a transitional large mammalian model of asphyxial cardiac arrest

Praveen Chandrasekharan; Payam Vali; Munmun Rawat; Bobby Mathew; Sylvia F. Gugino; Carmon Koenigsknecht; Justin Helman; Jayasree Nair; Sara K. Berkelhamer; Satyan Lakshminrusimha

Background:In neonates requiring chest compression (CC) during resuscitation, neonatal resuscitation program (NRP) recommends against relying on a single feedback device such as end-tidal carbon dioxide (ETCO2) or saturations (SpO2) to determine return of spontaneous circulation (ROSC) until more evidence becomes available.Methods:We evaluated the role of monitoring ETCO2 during resuscitation in a lamb model of cardiac arrest induced by umbilical cord occlusion (n = 21). Lambs were resuscitated as per NRP guidelines. Systolic blood pressure (SBP), carotid and pulmonary blood flows along with ETCO2 and blood gases were continuously monitored. Resuscitation was continued for 20 min or until ROSC (whichever was earlier). Adequate CC was arbitrarily defined as generation of 30 mmHg SBP during resuscitation. ETCO2 thresholds to predict adequacy of CC and detect ROSC were determined.Results:Significant relationship between ETCO2 and adequate CC was noted during resuscitation (AUC-0.735, P < 0.01). At ROSC (n = 12), ETCO2 rapidly increased to 57 ± 20 mmHg with a threshold of ≥32 mmHg being 100% sensitive and 97% specific to predict ROSC.Conclusion:In a large mammalian model of perinatal asphyxia, continuous ETCO2 monitoring predicted adequacy of CC and detected ROSC. These findings suggest ETCO2 in conjunction with other devices may be beneficial during CC and predict ROSC.


Pediatric Research | 2018

Effect of various inspired oxygen concentrations on pulmonary and systemic hemodynamics and oxygenation during resuscitation in a transitioning preterm model

Praveen Chandrasekharan; Munmun Rawat; Sylvia F. Gugino; Carmon Koenigsknecht; Justin Helman; Jayasree Nair; Payam Vali; Satyan Lakshminrusimha

BackgroundThe Neonatal Resuscitation Program recommends initial resuscitation of preterm infants with low oxygen (O2) followed by titration to target preductal saturations (SpO2). We studied the effect of resuscitation with titrated O2 on gas exchange, pulmonary, and systemic hemodynamics.MethodologyTwenty-nine preterm lambs (127 d gestation) were randomized to resuscitation with 21% O2 (n = 7), 100% O2 (n = 6), or initiation at 21% and titrated to target SpO2 (n = 16). Seven healthy term control lambs were ventilated with 21% O2.ResultsPreductal SpO2 achieved by titrating O2 was within the desired range similar to term lambs in 21% O2. Resuscitation of preterm lambs with 21% and 100% O2 resulted in SpO2 below and above the target, respectively. Ventilation of preterm lambs with 100% O2 and term lambs with 21% O2 effectively decreased pulmonary vascular resistance (PVR). In contrast, preterm lambs with 21% O2 and titrated O2 demonstrated significantly higher PVR than term lambs on 21% O2.Conclusion(s)Initial resuscitation with 21% O2 followed by titration of O2 led to suboptimal pulmonary vascular transition at birth in preterm lambs. Ventilation with 100% O2 in preterm lambs caused hyperoxia but reduced PVR similar to term lambs on 21% O2. Studies evaluating the initiation of resuscitation at a higher O2 concentration followed by titration based on SpO2 in preterm neonates are needed.


PLOS ONE | 2017

Hemodynamics and gas exchange during chest compressions in neonatal resuscitation

Payam Vali; Praveen Chandrasekharan; Munmun Rawat; Sylvia F. Gugino; Carmon Koenigsknecht; Justin Helman; Bobby Mathew; Sara K. Berkelhamer; Jayasree Nair; Myra H. Wyckoff; Satyan Lakshminrusimha

Purpose Current knowledge about pulmonary/systemic hemodynamics and gas exchange during neonatal resuscitation in a model of transitioning fetal circulation with fetal shunts and fluid-filled alveoli is limited. Using a fetal lamb asphyxia model, we sought to determine whether hemodynamic or gas-exchange parameters predicted successful return of spontaneous circulation (ROSC). Methods The umbilical cord was occluded in 22 lambs to induce asphyxial cardiac arrest. Following five minutes of asystole, resuscitation as per AHA-Neonatal Resuscitation Program guidelines was initiated. Hemodynamic parameters and serial arterial blood gases were assessed during resuscitation. Results ROSC occurred in 18 lambs (82%) at a median (IQR) time of 120 (105–180) seconds. There were no differences in hemodynamic parameters at baseline and at any given time point during resuscitation between the lambs that achieved ROSC and those that did not. Blood gases at arrest prior to resuscitation were comparable between groups. However, lambs that achieved ROSC had lower PaO2, higher PaCO2, and lower lactate during resuscitation. Increase in diastolic blood pressures induced by epinephrine in lambs that achieved ROSC (11 ±4 mmHg) did not differ from those that were not resuscitated (10 ±6 mmHg). Low diastolic blood pressures were adequate to achieve ROSC. Conclusions Hemodynamic parameters in a neonatal lamb asphyxia model with transitioning circulation did not predict success of ROSC. Lactic acidosis, higher PaO2 and lower PaCO2 observed in the lambs that did not achieve ROSC may represent a state of inadequate tissue perfusion and/or mitochondrial dysfunction.


Pediatric Research | 2016

Neonatal resuscitation adhering to oxygen saturation guidelines in asphyxiated lambs with meconium aspiration

Munmun Rawat; Praveen Chandrasekharan; Daniel D. Swartz; Bobby Mathew; Jayasree Nair; Sylvia F. Gugino; Carmon Koenigsknecht; Payam Vali; Satyan Lakshminrusimha

Background:The Neonatal Resuscitation Program (NRP) recommends upper and lower limits of preductal saturations (SpO2) extrapolated from studies in infants resuscitated in room air. These limits have not been validated in asphyxia and lung disease.Methods:Seven control term lambs delivered by cesarean section were ventilated with 21% O2. Thirty lambs with asphyxia with meconium aspiration were randomly assigned to resuscitation with 21% O2 (n = 6), 100% O2 (n = 6), or initiation with 21% O2 followed by variable FIO2 to maintain NRP target SpO2 ranges (n = 18). Hemodynamic and ventilation parameters were recorded for 15 min.Results:Control lambs maintained preductal SpO2 near the lower limit of NRP target range. Asphyxiated lambs had low SpO2 (38 ± 2%), low arterial pH (6.99 ± 0.01), and high PaCO2 (96 ± 7 mm Hg) at birth. Resuscitation with 21% O2 resulted in SpO2 values below the target range with low pulmonary blood flow (Qp) compared to variable FIO2 group. The increase in PaO2 and Qp with variable FIO2 resuscitation was similar to control lambs. Conclusion:Maintaining SpO2 as recommended by NRP by actively adjusting inspired O2 leads to effective oxygenation and higher Qp in asphyxiated lambs with lung disease. Our findings support the current NRP SpO2 guidelines for O2 supplementation during resuscitation of an asphyxiated neonate.


The Journal of Pediatrics | 2017

In quest of epinephrine's optimal route and dose in neonatal cardiopulmonary resuscitation—are we there yet?

Payam Vali; Bobby Mathew; Satyan Lakshminrusimha

To the Editor: The infrequent need for the use of epinephrine during neonatal resuscitation, coupled with our inability to anticipate consistently which newborns are at greatest risk of requiring extensive resuscitation, explains the ongoing lack of highquality evidence supported by large, randomized clinical trials on this subject. Therefore, large retrospective studies provide the greatest level of evidence on the efficacy of epinephrine during neonatal resuscitation. In their current study, Halling et al present interesting and valuable data, demonstrating that endotracheal (ET) and intravenous (IV) epinephrine administration at the lower dose recommended by the Neonatal Resuscitation Program (NRP) (0.05 mg/kg by ET and 0.01 mg/kg IV for the first dose) in most cases are insufficient to achieve return of spontaneous circulation (ROSC; 26% with ET and 20% with IV) and that repeat IV epinephrine doses are necessary to achieve ROSC. The majority of infants (74%) presented in asystole and would likely have a lower incidence of ROSC and require greater doses of epinephrine. Securing IV access during neonatal resuscitation takes approximately 6 minutes and may delay IV administration of epinephrine. Therefore, while IV access is attempted, the NRP recommends administering epinephrine through the ET as an alternative route. In a recent perinatal asphyxial cardiac arrest lamb model that mimicked newborns in the delivery room in need for cardiopulmonary resuscitation, we showed that ET epinephrine at the greater NRP-recommended dose of 0.1 mg/kg had a significantly lower success in achieving ROSC compared with IV administration of epinephrine at 0.03 mg/kg (55 vs 86%, respectively). Also, the peak plasma epinephrine concentrations were significantly lower following ET epinephrine. Could the authors elaborate: (1) why they chose to administer the lower dose of epinephrine, (2) the number of repeat IV epinephrine doses administered to infants who did not achieve ROSC, and (3) the comparison of ROSC rates with ET and IV epinephrine in infants with bradycardia vs asystole? Because of the poor response to ET (0.05 mg/kg) and IV (0.01 mg/kg) epinephrine, and to limit the need for repeat administration of epinephrine, the greater recommended ET epinephrine dose of 0.1 mg/kg and greater IV dose (0.03 mg/kg, as acknowledged by the authors) may be considered to improve the success in achieving ROSC and potentially limit neurologic morbidity and mortality, especially in infants presenting with asystole.


Children today | 2017

The Fetus Can Teach Us: Oxygen and the Pulmonary Vasculature

Payam Vali; Satyan Lakshminrusimha

Neonates suffering from pulmonary hypertension of the newborn (PPHN) continue to represent an important proportion of patients requiring intensive neonatal care, and have an increased risk of morbidity and mortality. The human fetus has evolved to maintain a high pulmonary vascular resistance (PVR) in utero to allow the majority of the fetal circulation to bypass the lungs, which do not participate in gas exchange, towards the low resistance placenta. At birth, oxygen plays a major role in decreasing PVR to enhance pulmonary blood flow and establish the lungs as the organ of gas exchange. The failure of PVR to fall following birth results in PPHN, and oxygen remains the mainstay therapeutic intervention in the management of PPHN. Knowledge gaps on what constitutes the optimal oxygenation target leads to a wide variation in practices, and often leads to excessive oxygen use. Owing to the risk of oxygen toxicity, avoiding hyperoxemia is as important as avoiding hypoxemia in the management of PPHN. Current evidence supports maintaining arterial oxygen tension in the range of 50–80 mm Hg, and oxygen saturation between 90–97% in term infants with hypoxemic respiratory failure. Clinical studies evaluating the optimal oxygenation in the treatment of PPHN will be enthusiastically awaited.

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Daniel D. Swartz

State University of New York System

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