SpO2 Target Research Articles

Computer model of oxygenation in neonates

Abstract Maintaining a prescribed peripheral oxygen saturation (SpO2) target during routine care of neonates is challenging and inspired fraction of oxygen (FiO2) titration practices differ among caregivers and centers. Algorithms for automatic feedback control of SpO2 are being developed and tested, that would adapt to the changing neonatal organism and better maintain the required SpO2 target range. While clinical data is necessary to validate differences in the titration strategies, a continuous physiological model of oxygenation in neonates would facilitate baseline testing of different approaches, manual or automated. The objective of our study was to enhance a mathematical model of oxygenation of the neonate and to compare the performance of the model with available clinical data. We have implemented the diffusion resistance into the model as well as a variable oxyhemoglobin dissociation relationship and the bias between arterial and peripheral oxygen saturation. Values of model parameters were scaled to fit preterm infant scenarios. The comparison of the clinical data and computer simulations suggest that the model can reliably simulate episodes of oxygen desaturation and describe the relation between ventilation, FiO2and SpO2. It appears that the model may be an effective tool to test manual and automatic FiO2titration strategies.

Using intermittent pulse oximetry to guide neonatal oxygen therapy in a low-resource context

ObjectiveTo evaluate the effectiveness of intermittent pulse oximetry in guiding oxygen therapy in neonates in a low-resource setting.Design and settingProspective validation study at three hospitals in southwest Nigeria. We performed...

Dutch Neonatal Intensive Care Nurses' Perceptions of Pulse Oximeter Saturation Target Limits for Preterm Infants

PurposeTo conduct a national survey to assess practice, knowledge, barriers, and perceptions regarding oxygen saturation (SpO2) target limits among Dutch neonatal intensive care unit (NICU) nurses. Design and methodsCross-sectional, web-based survey among 667 nurses from 9 level 3 Dutch NICUs. Part of the questions were based on a clinical scenario (28-weeks preterm infant, treated with CPAP, FiO2 0.4). Results328 (53.6%) nurses responded to the survey. Of these, 281 (85.7%) reported to know the local policy of SpO2 target limits, and 261 (79.6%) and 244 (74.4%) rightly identified the lower and upper limit, respectively. Six NICUs recently increased their lower SpO2 limit and for 62.0% of their nurses this led to a significant alarm increase. For the majority of the respondents, the baby from the clinical scenario would spend <10% of the time outside the lower or upper SpO2 limits. Automated oxygen control systems were considered a good idea by 59.2% of the respondents, but 53.9% considered allowing parents to participate in FiO2 titration a bad or very bad idea. ConclusionsThe majority of the respondents identified their unit's policy-specified SpO2 target limits and reported that the increase in SpO2 target limits may have led to more alarms. Titration of FiO2 is a part of care that respondents were reluctant to share with parents. Practice implicationsA potential increase in the number of SpO2 alarms may lead to alarm fatigue. Although family-centered care philosophy is widely accepted across Dutch NICUs, there are still barriers to overcome.

Current practice of prescription and administration of oxygen therapy: An observational study at a single teaching hospital.

ObjectivesOxygen therapy, commonly used clinically, should be administered according to the physician's prescription; however, accumulating evidence signals some degree of inaccuracy in this perspective. This study aimed to evaluate the current practice of prescription and administration of oxygen therapy.MethodsThis observational study was conducted at a teaching hospital in the Eastern province of KSA. All inpatients in general wards who were on supplemental oxygen (O2) were included. Patient's demographic data and physician's prescription items were collected from patient medical charts and the respiratory care (RC) department charts. Oxygen administration to inpatients was monitored and matched with oxygen prescriptions recorded on the medical and RC charts.ResultsAmong 152 inpatients, 21 were on supplemental O2. Of these, 20 had written prescriptions in their medical charts, but only 18 had information recorded in the RC charts. Of the 5 items required by hospital guidelines for oxygen prescription, 30% of patients had 3 items; whereas 70% of patients had only 2 items. Mode of oxygen delivery was recommended in all physicians' prescriptions, but flow rate and FiO2 were ordered in only 30% of prescriptions. Among the 6 patients with a written record of target SpO2 range, 2 had a value outside of the target range and 2 of 6 patients had a flow rate that differed from the prescribed rate.ConclusionCurrent practice for oxygen therapy prescription and administration was suboptimal. Nation-wide investigations and remediations of oxygen therapy practice is needed to improve patient care.

Oxygen Saturation Targeting During Delivery Room Stabilization: What Does This Mean for Regional Cerebral Oxygenation?

Objective: To investigate if preterm neonates with arterial oxygen saturation (SpO2)<80% at 5 min after birth show different regional cerebral tissue oxygen saturation (rcStO2), compared to infants reaching the target.Methods: Retrospective analysis of four prospective observational studies. Preterm neonates needing respiratory support during delivery room stabilization were included. Regional cerebral tissue oxygen saturation was measured with near-infrared spectroscopy (NIRS) during the first 15 min after birth along with SpO2 and heart rate (HR). Neonates were divided into two groups: those with a 5-min SpO2 ≥ 80% (“≥80% group”) and those with a 5-min SpO2 < 80% (“<80% group”). Groups were compared regarding rcStO2, SpO2, and HR. Furthermore, we analyzed whether a 5-min SpO2 < 80% was associated with a rcStO2 below the 10th percentile at the same time point.Results: 146 neonates were included, with 68 (47%) in the “≥80% group” and 78 (53%) in the “<80% group.” Neonates in the “ <80% group” had a significantly lower rcStO2 (p < 0.001). Furthermore, 80.3% of neonates in the “ <80% group” and 23.4% in the “≥80% group” had rcStO2 values below the 10th percentile at 5 min (p < 0.001). HR was significantly lower at minute 3 and 4 in the “ <80% group” (p < 0.002).Conclusion: Preterm infants needing respiratory support, who do not reach the SpO2 target of 80% at 5 min after birth, show significantly diminished rcStO2 values compared to neonates reaching the target.

Association Between Oxygen Saturation Targeting and Death or Disability in Extremely Preterm Infants in the Neonatal Oxygenation Prospective Meta-Analysis Collaboration

(JAMA. 2018;319(21):2190–2201) Oxygen saturation is almost universally measured by pulse oximetry (SpO2) in neonatal intensive care units. While a lower SpO2 target (≤90%) may reduce retinopathy of prematurity (ROP), it also may impair neurodevelopment or increase the risk of death. On the other hand, higher oxygen levels (SpO2 target &gt;90%) may increase the risk of adverse pulmonary sequelae. In 2003, 5 investigators planning separate randomized prospective clinical trials using similar study designs agreed to provide data after completion for a meta-analysis. This article detailed the results of the meta-analysis.

Evaluation of two SpO2 alarm strategies during automated FiO2 control in the NICU: a randomized crossover study

BackgroundChanges in oxygen saturation (SpO2) exposure have been shown to have a marked impact on neonatal outcomes and therefore careful titration of inspired oxygen is essential. In routine use, however, the frequency of SpO2 alarms not requiring intervention results in alarm fatigue and its corresponding risk. SpO2 control systems that automate oxygen adjustments (Auto-FiO2) have been shown to be safe and effective. We speculated that when using Auto-FiO2, alarm settings could be refined to reduce unnecessary alarms, without compromising safety.MethodsAn unblinded randomized crossover study was conducted in a single NICU among infants routinely managed with Auto-FiO2. During the first 6 days of respiratory support a tight and a loose alarm strategy were switched each 24 h. A balanced block randomization was used. The tight strategy set the alarms at the prescribed SpO2 target range, with a 30-s delay. The loose strategy set the alarms 2 wider, with a 90-s delay. The effectiveness outcome was the frequency of SpO2 alarms, and the safety outcomes were time at SpO2 extremes (< 80, > 98%). We hypothesized that the loose strategy would result in a marked decrease in the frequency of SpO2 alarms, and no increases at SpO2 extremes with 20 subjects. Within subject differences between alarm strategies for the primary outcomes were evaluated with Wilcoxon signed-rank test.ResultsDuring a 13-month period 26 neonates were randomized. The analysis included 21 subjects with 49 days of both tight and loose intervention. The loose alarm strategy resulted in a reduction in the median rate of SpO2 alarms from 5.2 to 1.6 per hour (p < 0.001, 95%-CI difference 1.6–3.7). The incidence of hypoxemia and hyperoxemia were very low (less than 0.1%-time) with no difference associated with the alarm strategy (95%-CI difference less than 0.0–0.2%).ConclusionsIn this group of infants we found a marked advantage of the looser alarm strategy. We conclude that the paradigms of alarm strategies used for manual titration of oxygen need to be reconsidered when using Auto-FiO2. We speculate that with optimal settings false positive SpO2 alarms can be minimized, with better vigilance of clinically relevant alarms.Trial registrationRetrospectively registered 15 May 2018 at ISRCTN (49239883).

Reduced blood oxygen levels induce changes in low-threshold motor unit firing that align with the individual's tolerance to hypoxia.

This study aimed to quantify how acute hypoxia impacts firing characteristics of biceps brachii motor units (MUs) during sustained isometric elbow flexions. MU data were extracted from surface electromyography (EMG) during 25% maximal voluntary contractions (MVC) in 10 healthy subjects (age 22 ± 1 yr). Blood oxygen saturation (SpO2) was then stabilized at 80% by reducing 1% of the fraction of inspired oxygen every 3 min for 35 min. MU data were once again collected 1 h and 2 h following the 35-min desaturation phase. Although MVC remained unaffected during 2 h of 80% SpO2, subject-specific changes in MU firing rate were observed. Four of 10 subjects exhibited a decrease in firing rate 1 h postdesaturation (12 ± 11%) and 2 h postdesaturation (16 ± 12%), whereas 6 of 10 subjects exhibited an increase in firing rate 1 h (9 ± 6%) and 2 h (9 ± 4%) postdesaturation. These bidirectional changes in firing rate were strongly correlated to the desaturation phase and the subjects' SpO2 sensitivity to oxygen availability, where subjects who had decreased firing rates reached the target SpO2 20 min into the desaturation phase (R2 = 0.90-0.98) and those who had increased firing rates reached the target SpO2 35 min into the desaturation phase (R2 = 0.87-0.98). It is unlikely that a single mechanism accounted for these subject-specific changes in firing rate. Instead, differences in intrinsic properties of the neurons, afferent input to the motoneurons, neuromodulators, and sympathetic nerve activity may exist between groups. NEW & NOTEWORTHY The mechanisms of compromised motor control when exposed to hypoxia are largely unknown. The current study examined how severe acute hypoxia affects motor unit firing rate during sustained isometric contractions of the bicep brachii. The response to hypoxia was different across subjects, where motor unit firing rate increased for some individuals and decreased for others. This bidirectional change in firing rate was associated with how fast subjects desaturated during hypoxic exposure.

Conservative versus conventional oxygen therapy for cardiac surgical patients: A before-and-after study.

Avoiding hypoxaemia is considered crucial in cardiac surgery patients admitted to the intensive care unit (ICU). However, avoiding hyperoxaemia may also be important. A conservative approach to oxygen therapy may reduce exposure to hyperoxaemia without increasing the risk of hypoxaemia. Using a before-and-after design, we evaluated the introduction of conservative oxygen therapy (target SpO2 88%-92% using the lowest FiO2) for cardiac surgical patients admitted to the ICU. We studied 9041 arterial blood gas (ABG) datasets: 4298 ABGs from 245 'conventional' and 4743 ABGs from 298 'conservative' oxygen therapy patients. During mechanical ventilation (MV) and while in the ICU, compared to the conventional group, conservative group patients had significantly lower FiO2 exposure and PaO2 values ( P < 0.001 for each). Accordingly, using the mean PaO2 during MV, more conservative group patients were classified as normoxaemic (226 versus 62 patients, P < 0.01), fewer as hyperoxaemic (66 versus 178 patients, P < 0.01) and no patient in either group as hypoxaemic or severely hypoxaemic. Moreover, more ABG samples were hyperoxaemic or severely hyperoxaemic during conventional treatment ( P < 0.001). Finally, there was no difference in ICU or hospital length of stay, ICU or hospital mortality or 30-day mortality between the groups. Our findings support the feasibility and physiological safety of conservative oxygen therapy in patients admitted to ICU after cardiac surgery.

Automated control of inspired oxygen (FiO2 ) in preterm infants: Literature review.

The vast majority (95%) of very preterm infants receive oxygen-therapy monitored by oxygen pulse saturation (SpO2 ). However, they spend a significant percentage of time out of the SpO2 target with a high risk of severe complications such as bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP). Recently, systems allowing the automated control of inspired oxygen (FiO2 ) for patient delivery to maintain target SpO2 has been become commercially available. We reviewed literature and individuated sixteen studies on the effectiveness of automated control of FiO2 in preterm infants. These studies demonstrate that automated devices are significantly more effective than manual control in maintaining target SpO2 and in preventing hyperoxia, while they seem to be less effective in preventing hypoxia. The studies were very heterogeneous for design, population size, duration, and device used, and this precludes firm conclusions regarding effectiveness and best setting of these systems. Moreover, none of the studies investigated if automated control of FiO2 can actually improve outcome in preterm infants. We conclude that further large-scale studies are warranted to assess the actual clinical relevance of these devices and to decide if they should become the standard of care.

Protocol for a feasibility randomised controlled trial of targeted oxygen therapy in mechanically ventilated critically ill patients

IntroductionOxygen is the most commonly administered drug to mechanically ventilated critically ill adults, yet little is known about the optimum oxygen saturation (SpO2) target for these patients; the current standard...

Design and Conduct of The New Zealand Oxygen Therapy in Acute Coronary Syndromes Trial

The New Zealand oxygen trial was designed to determine whether supplemental oxygen influences 30-day mortality in patients presenting with suspected acute coronary syndrome (ACS). Methods: This trial evaluated two oxygen protocols administered as part of usual care by the ambulance, emergency department, coronary care unit (CCU), and cardiac catheter lab to patients presenting with proven or suspected ACS. The high oxygen strategy recommended: “give oxygen for ischaemic chest pain or ischaemic ECG changes and maintain SpO2 ≥95%”. The Conservative oxygen strategy recommended: “Do not give oxygen unless the measured oxygen saturation is consistently <90%. If oxygen is given, aim target SpO2 90 to 94%.” Randomisation was by regional cardiac clinical network (n = 4) and study period. The study population included patients attended by the ambulance service managed on the ACS pathway or with an ACS and included in the All New Zealand Acute Coronary Syndrome-Quality Improvement (ANZACS-QI) registry between 11 July 2016 and 11 July 2018, excluding two 2-week crossover periods. Data for the primary outcome of 30-day total mortality are currently awaited. Information on study conduct, audit of protocol adherence, and comparison with other reported trials will be presented. Conclusion: The New Zealand oxygen study demonstrates that simple pragmatic trials can be undertaken at modest cost in NZ as part of usual care. Results will inform whether oxygen administration has a neutral, favourable, or unfavourable effect on 30-day mortality in patients presenting with a suspected ACS.

Pulsed Dose Oxygen Delivery During Mechanical Ventilation: Impact on Oxygenation.

Adequate oxygenation is one of the primary goals of mechanical ventilation. Maintenance of adequate oxygenation and prevention of hypoxemia are the primary goals for the battlefield casualty, but military operations have unique concerns. In military operations, oxygen is a limited resource. A portable oxygen concentrator has the advantage of operating solely from electrical power and theoretically is a never-exhausting supply of oxygen. Our previous bench work demonstrated that the pulsed dose setting of the concentrator can be used in concert with the ventilator to maximize oxygen delivery. We evaluated this ventilator/concentrator system with closed loop control of oxygen output in a porcine model. The Zoll 731 portable ventilator and Sequal Saros portable oxygen concentrator were used for this study. The ventilator and concentrator were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation (SpO2) via the integral pulse oximetry sensor. The ventilator communicates with the concentrator to increase or decrease oxygen bolus size to maintain a target SpO2 of 94%. Three separate experiments were conducted in this study. Experiments 1 and 2 used oxygen bolus sizes 16-96 mL in 16-mL increments and experiment 3 used 1 mL increments. The oxygen bolus was delivered from the concentrator and injected into the ventilator circuit at the patient connector. Six pigs were used for each experiment. Experiment 1, done without lung injury, was completed to determine the optimum timing during the respiratory cycle for injecting the oxygen bolus. Lung injury for experiments 2 and 3 was induced in the animals by warmed saline lavage via the endotracheal tube until PaO2/FIO2 decreased to <100. The pigs were then placed on the ventilator/concentrator system and allowed to adjust the oxygen autonomously to determine if the target SpO2 could be maintained. PEEP was manually adjusted. Arterial blood gases were drawn to verify the PaO2 and the SpO2/SaO2 correlation. Experiment 1 showed that the O2 bolus injected into the ventilator circuit 300 ms before breath delivery produced the highest PaO2. Mean PaO2/FIO2 was 500 ± 33 for experiments 2 and 3 before lung lavage and 72 ± 11 after lung lavage (p < 0.001), representing severe acute respiratory distress syndrome. Thirty minutes after placing the animals on the ventilator/concentrator system, the bolus size range was 64-96 mL and 16-96 mL after 2 hours (p < 0.05). The SpO2 range was 81-95% after 30 minutes and 94-98% after 2 hours (p < 0.05). PEEP range was 5-14 cm H2O. The SpO2 to SaO2 difference was ≤4% throughout the evaluation. The ventilator/concentrator system was able to manage oxygenation of severely injured lungs in a porcine model by injecting oxygen boluses at the front end of the ventilator breath, and appropriate use of PEEP to maximize oxygen delivery at the alveolar level. This proof of concept ventilator system may prove to be of use in situations where high-pressure oxygen is unavailable but electricity is accessible.

Randomised cross-over study of automated oxygen control for preterm infants receiving nasal high flow

ObjectiveTo evaluate a prototype automated controller (IntellO2) of the inspired fraction of oxygen (FiO2) in maintaining a target range of oxygen saturation (SpO2) in preterm babies receiving nasal high flow...

Target Oxygen Saturation Among Preterm Neonates on Supplemental Oxygen Therapy: A Quality Improvement Study

To avoid excessive oxygen exposure and achieve target oxygen saturation (SpO2) within intended range of 88%-95% among preterm neonates on oxygen therapy. 20 preterm neonates receiving supplemental oxygen in the first week of life were enrolled. The percentage of time per epoch (a consecutive time interval of 10 hours/day) spent by them within the target SpO2 range was measured in phase 1 followed by implementation of a unit policy on oxygen administration and targeting in phase 2. In phase 3, oxygen saturation histograms constructed from pulse-oximeter data were used as daily feedback to nurses and compliance with oxygen-targeting was measured again. 48 epochs in phase 1 and 69 in phase 3 were analyzed. The mean (SD) percent time spent within target SpO2 range increased from 65.9% (21.4) to 76.5% (12.6) (P=0.001). Effective implementation of oxygen targeting policy and feedback using oxygen saturation histograms may improve compliance with oxygen targeting.

Effects of a new device for automated closed loop control of inspired oxygen concentration on fluctuations of arterial and different regional organ tissue oxygen saturations in preterm infants

ObjectiveTo assess the efficacy of a newly developed system for closed loop control of the fraction of inspired oxygen (FiO2) on variation of arterial (SpO2) and on regional tissue oxygen...

Preterm Infant Outcomes after Randomization to Initial Resuscitation with FiO2 0.21 or 1.0

To determine rates of death or neurodevelopmental impairment (NDI) at 2 years corrected age (primary outcome) in children <32 weeks' gestation randomized to initial resuscitation with a fraction of inspired oxygen (FiO2) value of 0.21 or 1.0. Blinded assessments were conducted at 2-3 years corrected age with the Bayley Scales of Infant and Toddler Development, Third Edition or the Ages and Stages Questionnaire by intention to treat. Of the 290 children enrolled, 40 could not be contacted and 10 failed to attend appointments. Among the 240 children for whom outcomes at age 2 years were available, 1 child had a lethal congenital anomaly, 1 child had consent for follow-up withdrawn, and 23 children died. The primary outcome, which was available in 238 (82%) of those randomized, occurred in 47 of the 117 (40%) children assigned to initial FiO2 0.21 and in 38 of the 121 (31%) assigned to initial FiO2 1.0 (OR, 1.47; 95% CI, 0.86-2.5; P = .16). No difference in NDI was found in 215 survivors randomized to FiO2 0.21 vs 1.0 (OR, 1.26; 95% CI, 0.70-2.28; P = .11). In post hoc exploratory analyses in the whole cohort, children with a 5-minute blood oxygen saturation (SpO2) <80% were more likely to die or to have NDI (OR, 1.85; 95% CI, 1.07-3.2; P = .03). Initial resuscitation of infants <32 weeks' gestation with initial FiO2 0.21 had no significant effect on death or NDI compared with initial FiO2 1.0. Further evaluation of optimum initial FiO2, including SpO2 targeting, in a large randomized controlled trial is needed. Australian and New Zealand Clinical Trials Network Registry ACTRN 12610001059055 and the National Malaysian Research Registry NMRR-07-685-957.

Comparison of Automated and Manual Peripheral Oxygen Saturation Control Applied to One Human Subject at a High Target Range.

Newborn infants, mainly those born prematurely, often require respiratory support with a varying concentration of the fraction of inspired oxygen (FiO$_{\mathbf {2}}$) to keep the peripheral oxygen saturation (SpO$_{\mathbf {2}}$) within the desired range to prevent adverse health effects due to both high and low SpO$_{\mathbf {2}}$. Manual adjustment, by nurses, is the common practice. However, the efficacy of the manual control is questionable. A novel automatic controller is evaluated clinically with application to one human subject at a high target SpO$_{\mathbf {2}}$. The automatic controller demonstrated the ability to improve oxygen saturation control over the everyday routine manual control by increasing the proportion of time where SpO$_{\mathbf {2}}\textbf{v}$alues were within the desired range.

Association Between Oxygen Saturation Targeting and Death or Disability in Extremely Preterm Infants in the Neonatal Oxygenation Prospective Meta-analysis Collaboration

There are potential benefits and harms of hyperoxemia and hypoxemia for extremely preterm infants receiving more vs less supplemental oxygen. To compare the effects of different target ranges for oxygen saturation as measured by pulse oximetry (Spo2) on death or major morbidity. Prospectively planned meta-analysis of individual participant data from 5 randomized clinical trials (conducted from 2005-2014) enrolling infants born before 28 weeks' gestation. Spo2 target range that was lower (85%-89%) vs higher (91%-95%). The primary outcome was a composite of death or major disability (bilateral blindness, deafness, cerebral palsy diagnosed as ≥2 level on the Gross Motor Function Classification System, or Bayley-III cognitive or language score <85) at a corrected age of 18 to 24 months. There were 16 secondary outcomes including the components of the primary outcome and other major morbidities. A total of 4965 infants were randomized (2480 to the lower Spo2 target range and 2485 to the higher Spo2 range) and had a median gestational age of 26 weeks (interquartile range, 25-27 weeks) and a mean birth weight of 832 g (SD, 190 g). The primary outcome occurred in 1191 of 2228 infants (53.5%) in the lower Spo2 target group and 1150 of 2229 infants (51.6%) in the higher Spo2 target group (risk difference, 1.7% [95% CI, -1.3% to 4.6%]; relative risk [RR], 1.04 [95% CI, 0.98 to 1.09], P = .21). Of the 16 secondary outcomes, 11 were null, 2 significantly favored the lower Spo2 target group, and 3 significantly favored the higher Spo2 target group. Death occurred in 484 of 2433 infants (19.9%) in the lower Spo2 target group and 418 of 2440 infants (17.1%) in the higher Spo2 target group (risk difference, 2.8% [95% CI, 0.6% to 5.0%]; RR, 1.17 [95% CI, 1.04 to 1.31], P = .01). Treatment for retinopathy of prematurity was administered to 220 of 2020 infants (10.9%) in the lower Spo2 target group and 308 of 2065 infants (14.9%) in the higher Spo2 target group (risk difference, -4.0% [95% CI, -6.1% to -2.0%]; RR, 0.74 [95% CI, 0.63 to 0.86], P < .001). Severe necrotizing enterocolitis occurred in 227 of 2464 infants (9.2%) in the lower Spo2 target group and 170 of 2465 infants (6.9%) in the higher Spo2 target group (risk difference, 2.3% [95% CI, 0.8% to 3.8%]; RR, 1.33 [95% CI, 1.10 to 1.61], P = .003). In this prospectively planned meta-analysis of individual participant data from extremely preterm infants, there was no significant difference between a lower Spo2 target range compared with a higher Spo2 target range on the primary composite outcome of death or major disability at a corrected age of 18 to 24 months. The lower Spo2 target range was associated with a higher risk of death and necrotizing enterocolitis, but a lower risk of retinopathy of prematurity treatment.

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

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 (127d-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 initiation of resuscitation at higher O2 concentration followed by titration based on SpO2 in preterm neonates are needed.