Automated versus manual control of inspired oxygen to target oxygen saturation in preterm infants: a systematic review and meta-analysis

Comparison of two different oxygen saturation target ranges for automated oxygen control in preterm infants: a randomised cross-over trial

OBJECTIVE

To compare the effect of peripheral oxygen saturation (SpO2) target range (TR) (either 91%-95% and 92%-96%) on the frequency and duration of hypoxic and hyperoxic episodes while on automated oxygen control using the OxyGenie controller.

DESIGN

Randomised cross-over study.

SETTING

Tertiary-level neonatal unit in the Netherlands.

PATIENTS

Infants (n=27) with a median (IQR) gestational age of 27+0 (25+5-27+3) weeks and postnatal age of 16 (10-22) days, receiving invasive or non-invasive respiratory support.

INTERVENTIONS

In both groups supplemental oxygen was titrated to a TR of 91%-95% (TRlow) or 92%-96% (TRhigh) by the OxyGenie controller (SLE6000 ventilator) for 24 hours each, in random sequence. After a switch in TR, a 1-hour washout period was applied to prevent carry-over bias.

MAIN OUTCOME MEASURES

Frequency and duration of hypoxic (SpO2<80% for ≥1 s) and hyperoxic episodes (SpO2>98% for ≥1 s).

RESULTS

Hypoxic episodes were less frequent when the higher range was targeted (TRhigh vs TRlow: 2.5 (0.7-6.2)/hour vs 2.4 (0.9-10.2)/hour, p=0.02), but hyperoxic episodes were more frequent (5.3 (1.8-12.3)/hour vs 2.9 (1.0-7.1)/hour, p<0.001). The duration of the out-of-range episodes was not significantly different (hypoxia: 4.7 (2.8-7.1) s vs 4.4 (3.7-6.5) s, p=0.67; hyperoxia: 4.3 (3.3-4.9) s vs 3.9 (2.8-5.5) s, p=0.89).

CONCLUSION

Targeting a higher SpO2 TR with the OxyGenie controller reduced hypoxic episodes but increased hyperoxic episodes. This study highlights the feasibility of using an automated oxygen titration device to explore the effects of subtle TR adjustments on clinical outcomes in neonatal care.

TRIAL REGISTRATION NUMBER

NL9662.

Initial Oxygen Concentration for the Resuscitation of Infants Born at Less Than 32 Weeks' Gestation: A Systematic Review and Individual Participant Data Network Meta-Analysis

Importance

Resuscitation with lower fractional inspired oxygen (FiO2) reduces mortality in term and near-term infants but the impact of this practice on very preterm infants is unclear.

Objective

To evaluate the relative effectiveness of initial FiO2 on reducing mortality, severe morbidities, and oxygen saturations (SpO2) in preterm infants born at less than 32 weeks' gestation using network meta-analysis (NMA) of individual participant data (IPD).

Data Sources

MEDLINE, Embase, CENTRAL, CINAHL, ClinicalTrials.gov, and WHO ICTRP from 1980 to October 10, 2023.

Study Selection

Eligible studies were randomized clinical trials enrolling infants born at less than 32 weeks' gestation comparing at least 2 initial oxygen concentrations for delivery room resuscitation, defined as either low (≤0.3), intermediate (0.5-0.65), or high (≥0.90) FiO2.

Data Extraction and Synthesis

Investigators from eligible studies were invited to provide IPD. Data were processed and checked for quality and integrity. One-stage contrast-based bayesian IPD-NMA was performed with noninformative priors and random effects and adjusted for key covariates.

Main Outcomes and Measures

The primary outcome was all-cause mortality at hospital discharge. Secondary outcomes were morbidities of prematurity and SpO2 at 5 minutes.

Results

IPD were provided for 1055 infants from 12 of the 13 eligible studies (2005-2019). Resuscitation with high (≥0.90) initial FiO2 was associated with significantly reduced mortality compared to low (≤0.3) (odds ratio [OR], 0.45; 95% credible interval [CrI], 0.23-0.86; low certainty) and intermediate (0.5-0.65) FiO2 (OR, 0.34; 95% CrI, 0.11-0.99; very low certainty). High initial FiO2 had a 97% probability of ranking first to reduce mortality. The effects on other morbidities were inconclusive.

Conclusions and Relevance

High initial FiO2 (≥0.90) may be associated with reduced mortality in preterm infants born at less than 32 weeks' gestation compared to low initial FiO2 (low certainty). High initial FiO2 is possibly associated with reduced mortality compared to intermediate initial FiO2 (very low certainty) but more evidence is required.

Pulse oximetry signal loss during hypoxic episodes in preterm infants receiving automated oxygen control

The aim of this study was to analyze signal loss (SL) resulting from low signal quality of pulse oximetry-derived hemoglobin oxygen saturation (SpO2) measurements during prolonged hypoxemic episodes (pHE) in very preterm infants receiving automatic oxygen control (AOC). We did a post hoc analysis of a randomized crossover study of AOC, programmed to set FiO2 to "back-up FiO2" during SL. In 24 preterm infants (median (interquartile range)) gestational age 25.3 (24.6 to 25.6) weeks, recording time 12.7 h (12.2 to 13.6 h) per infant, we identified 76 pHEs (median duration 119 s (86 to 180 s)). In 50 (66%) pHEs, SL occurred for a median duration of 51 s (33 to 85 s) and at a median frequency of 2 (1 to 2) SL-periods per pHE. SpO2 before and after SL was similar (82% (76 to 88%) vs 82% (76 to 87%), p = 0.3)).  Conclusion: SL is common during pHE and must hence be considered in AOC-algorithm designs. Administering a "backup FiO2" (which reflects FiO2-requirements during normoxemia) during SL may prolong pHE with SL.  Trial registration: The study was registered at www.

CLINICALTRIALS

gov under the registration no. NCT03785899.

WHAT IS KNOWN

• Previous studies examined SpO2 signal loss (SL) during routine manual oxygen control being rare, but pronounced in lower SpO2 states. • Oxygen titration during SL is unlikely to be beneficial as SpO2 may recover to a normoxic range.

WHAT IS NEW

• Periods of low signal quality of SpO2 are common during pHEs and while supported with automated oxygen control (SPOC), FiO2 is set to a back-up value reflecting FiO2 requirements during normoxemia in response to SL, although SpO2 remained below target until signal recovery. • FiO2 overshoots following pHEs were rare during AOC and occurred with a delayed onset; therefore, increased FiO2 during SL does not necessarily lead to overshoots.

Occurrence of hyperoxia during iNO treatment for persistent pulmonary hypertension of the newborn: a cohort study

High concentrations of oxygen are often needed to optimize oxygenation in infants with persistent pulmonary hypertension (PPHN), but this can also increase the risk of hyperoxemia. We determined the occurrence of hyperoxemia in infants treated for PPHN. Medical records of infants ≥ 34 + 0 weeks gestational age (GA) who received inhaled nitric oxide (iNO) were retrospectively reviewed for oxygenation parameters during iNO therapy. Oxygen was manually titrated to target arterial oxygen tension (PaO2) 10-13 kPa and peripheral oxygen saturation (SpO2) 92-98%. The main study outcomes were the incidence and duration of hyperoxemia and hypoxemia and the fraction of inspired oxygen (FiO2). A total of 181 infants were included. The median FiO2 was 0.43 (IQR 0.34-0.56) and the maximum FiO2 was 1.0 in 156/181 (86%) infants, resulting in at least one PaO2 > 13 kPa in 149/181 (82%) infants, of which 46/149 (31%) infants had minimal one PaO2 > 30 kPa. SpO2 was > 98% in 179/181 (99%) infants for 17.7% (8.2-35.6%) of the iNO time. PaO2 < 10 kPa occurred in 160/181 (88%) infants, of which 81/160 (51%) infants had minimal one PaO2 < 6.7 kPa. SpO2 was < 92% in 169/181 (93%) infants for 1.6% (0.5-4.3%) of the iNO time.    Conclusion: While treatment of PPHN is focused on preventing and reversing hypoxemia, hyperoxemia occurs inadvertently in most patients. What is Known: • High concentrations of oxygen are often needed to prevent hypoxemia-induced deterioration of PPHN, but this can also increase the risk of hyperoxemia. • Infants with persistent pulmonary hypertension may be particularly vulnerable to the toxic effects of oxygen, and hyperoxemia could further induce pulmonary vasoconstriction, potentially worsening the condition. What is New: • Hyperoxemia occurs in the majority of infants with PPHN during treatment with iNO. • Infants with PPHN spent a considerably longer period with saturations above the target range compared to saturations below the target range.

Prolonged use of closed-loop inspired oxygen support in preterm infants: a randomised controlled trial

OBJECTIVE

This randomised study in preterm infants on non-invasive respiratory support investigated the effectiveness of automated oxygen control (A-FiO2) in keeping the oxygen saturation (SpO2) within a target range (TR) during a 28-day period compared with manual titration (M-FiO2).

DESIGN

A single-centre randomised control trial.

SETTING

A level III neonatal intensive care unit.

PATIENTS

Preterm infants (<28 weeks' gestation) on non-invasive respiratory support.

INTERVENTIONS

A-FiO2 versus M-FiO2 control.

METHODS

Main outcomes were the proportion of time spent and median area of episodes in the TR, hyperoxaemia, hypoxaemia and the trend over 28 days using a linear random intercept model.

RESULTS

23 preterm infants (median gestation 25.7 weeks; birth weight 820 g) were randomised. Compared with M-FiO2, the time spent within TR was higher in the A-FiO2 group (68.7% vs 48.0%, p<0.001). Infants in the A-FiO2 group spent less time in hyperoxaemia (13.8% vs 37.7%, p<0.001), but no difference was found in hypoxaemia. The time-based analyses showed that the A-FiO2 efficacy may differ over time, especially for hypoxaemia. Compared with the M-FiO2 group, the A-FiO2 group had a larger intercept but with an inversed slope for the daily median area below the TR (intercept 70.1 vs 36.3; estimate/day -0.70 vs 0.69, p<0.001).

CONCLUSION

A-FiO2 control was superior to manual control in keeping preterm infants on non-invasive respiratory support in a prespecified TR over a period of 28 days. This improvement may come at the expense of increased time below the TR in the first days after initiating A-FiO2 control.

TRIAL REGISTRATION NUMBER

NTR6731.

Association between intermittent hypoxemia and neurodevelopmental outcomes in extremely premature infants: A single-center experience

OBJECTIVE

To describe the association between intermittent hypoxemic events (IHEs) and severe neurodevelopmental impairment (SNDI) or death in extremely premature infants.

STUDY DESIGN

Retrospective study of extremely premature infants 230/7-276/7 weeks gestational age (GA) and birthweight (BW) ≤1250 grams (g) admitted to a level IV neonatal intensive care unit (NICU) from 2013 to 2017. IHEs, defined as events with SpO2 ≤ 80 % lasting 10 s to 5 min, were algorithmically identified using data extracted from bedside monitors at 2 s intervals (0.5 Hz). The primary outcome was SNDI at 18-24 months corrected age (CA), defined as a Bayley-III motor, language or cognitive composite score ≤69, or death before discharge while the secondary outcome was SNDI alone. We used mixed-effects regression models to evaluate the relationship between mean daily IHE rate per postnatal week of life for the first 12 weeks and the outcomes, and logistic regression models to assess the association between outcomes and summary measures of hypoxic burden for the entire NICU hospitalization.

RESULTS

The mortality rate was 7 % (18/249) during NICU hospitalization. Of 249 infants born during this time period, IHE and neurodevelopmental outcome data were fully available for 65 infants (mean GA 26 ± 1.4 weeks, mean birth weight (BW) 738 ± 199 g. The outcome of SNDI alone occurred in 34 % (22/65) with a majority demonstrating motor or language delay on the Bayley-III. Although mean daily IHE rate/week was not associated with SNDI or death, total IHE duration was associated with increased odds of SNDI (OR (95 % CI) 1.03 (1.01, 1.05), p = 0.008) in models adjusted for GA.

CONCLUSIONS

In a cohort of extremely premature infants 23-27 weeks GA, each hour of total IHE duration (SpO2 ≤ 80 %) was associated with a 2.7 % (0.7 %, 4.8 %) increase in the odds of SNDI at 18-24 months CA.

Measuring Oxygenation in Newborn Infants with Targeted Oxygen Ranges (MONITOR): a randomised crossover pilot study

OBJECTIVE

The Neonatal Oxygenation Prospective Meta-analysis (NeOProM) Collaboration showed that high (91-95%) versus low (85-89%) SpO2 targets reduced mortality. Trials of higher targets are needed to determine whether any more survival advantage may be gained. This pilot study explored the achieved oxygenation patterns observed when targeting SpO2 92-97% to facilitate the design of future trials.

DESIGN

Single-centre prospective randomised crossover pilot study. Manual FiO2 adjustment. Study time 12 hours per infant. 6 hours targeting SpO2 90-95% and 6 hours targeting SpO2 92-97%.

PATIENTS

Twenty preterm infants born <29 weeks' gestation, greater than 48 hours old, receiving supplemental oxygen.

OUTCOMES

Primary outcome was percentage time with SpO2 above 97% and below 90%. Pre-defined secondary outcomes included percentage time spent within, above or below transcutaneous PO2 (TcPO2) 6.7-10.7 kPa (50-80 mm Hg). Comparisons were made using paired-samples t-test (2-tailed).

RESULTS

With SpO2 target 92-97% versus 90-95%, the mean (IQR) percentage time above SpO2 97% was 11.3% (2.7-20.9) versus 7.8% (1.7-13.9), p=0.02. Percentage time with SpO2 <90% was 13.1% (6.7-19.1) versus 17.9% (11.1-22.4), p=0.003. Percentage time with SpO2 <80% was 1% (0.1-1.4) versus 1.6% (0.4-2.6), p=0.119. Percentage time with TcPO2 <6.7 kPa (50 mm Hg) was 49.6% (30.2-66.0) versus 55% (34.3-73.5), p=0.63. Percentage time above TcPO2 10.7 kPa (80 mm Hg) was 1.4% (0-1.4) versus 1.8% (0-0), p=0.746.

CONCLUSIONS

Targeting SpO2 92-97% produced a right shift in SpO2 and TcPO2 distribution, with reduced time at SpO2 <90% and increased time at SpO2 >97%, without increasing time with TcPO2 >10.7 kPa (80 mm Hg). Clinical trials targeting this higher SpO2 range could be conducted without significant hyperoxic exposure.

TRIAL REGISTRATION NUMBER

NCT03360292.

Does closed-loop automated oxygen control reduce the duration of supplementary oxygen treatment and the amount of time spent in hyperoxia? A randomised controlled trial in ventilated infants born at or near term

BACKGROUND

Ventilated infants frequently require supplemental oxygen, but its use should be monitored carefully due to associated complications. The achievement of oxygen saturation (SpO₂) targets can be challenging as neonates experience frequent fluctuations of their oxygen levels that further increase the risk of complications. Closed-loop automated oxygen control systems (CLAC) improve achievement of oxygen saturation targets, reduce hyperoxaemic episodes and facilitate weaning of the inspired oxygen concentration in ventilated infants born at or near term. This study investigates whether CLAC compared with manual oxygen control reduces the time spent in hyperoxia and the overall duration of supplemental oxygen treatment in ventilated infants born at or above 34 weeks gestation.

METHODS

This randomised controlled trial performed at a single tertiary neonatal unit is recruiting 40 infants born at or above 34 weeks of gestation and within 24 h of initiation of mechanical ventilation. Infants are randomised to CLAC or manual oxygen control from recruitment till successful extubation. The primary outcome is the percentage of time spent in hyperoxia (SpO₂ > 96%). The secondary outcomes are the overall duration of supplementary oxygen treatment, the percentage of time spent with an oxygen requirement above thirty per cent, the number of days on mechanical ventilation and the length of neonatal unit stay. The study is performed following informed parental consent and was approved by the West Midlands-Edgbaston Research Ethics Committee (Protocol version 1.2, 10/11/2022).

DISCUSSION

This trial will investigate the effect of CLAC on the overall duration of oxygen therapy and the time spent in hyperoxia. These are important clinical outcomes as hyperoxic injury is related to oxidative stress that can adversely affect multiple organ systems.

TRIAL REGISTRATION

ClinicalTrials.Gov NCT05657795. Registered on 12/12/2022.

Closed-loop automated oxygen control in ventilated infants born at or near term: A crossover trial

AIM

To determine if the use of closed-loop automated oxygen control (CLAC) reduced the incidence and duration of hypoxemic episodes (SpO₂  < 92%) in ventilated infants born at or above 34 weeks of gestation.

METHODS

Infants were studied on two consecutive days for 6 h each day. They were randomised to receive standard care (manual oxygen control) or standard care with a CLAC system (automated oxygen control) first.

RESULTS

Sixteen infants with a median (IQR) gestational age of 37.4 (36.6-38.8) weeks were studied at a median (IQR) postmenstrual age of 38.8 (37.4-39.8) weeks. During the automated oxygen control period, infants spent less time in hypoxemia (SpO₂  < 92%) (p = 0.033), episodes of desaturation were shorter (p = 0.001), the time spent within target SpO₂ range (92%-96%) was increased (p = 0.001), and the FiO₂ delivery was lower (p = 0.018). The time spent in hyperoxemia (SpO₂  > 96%) was reduced during automated oxygen control (p = 0.011), the episodes of hyperoxemia were of shorter duration (p = 0.008) and fewer manual adjustments were made to the FiO₂ (p = 0.005).

CONCLUSIONS

Closed-loop automated oxygen control in ventilated infants born at or near term was associated with a reduction in the incidence and duration of hypoxemic episodes with more time spent in the target oxygen range.

Comparison of two automated oxygen controllers in oxygen targeting in preterm infants during admission: an observational study

OBJECTIVE

To compare the effect of two different automated oxygen control devices on time preterm infants spent in different oxygen saturation (SpO₂) ranges during their entire stay in the neonatal intensive care unit (NICU).

DESIGN

Retrospective cohort study of prospectively collected data.

SETTING

Tertiary level neonatal unit in the Netherlands.

PATIENTS

Preterm infants (OxyGenie 75 infants, CLiO₂ 111 infants) born at 24-29 weeks' gestation receiving at least 72 hours of respiratory support between October 2015 and November 2020.

INTERVENTIONS

Inspired oxygen concentration was titrated by the OxyGenie controller (SLE6000 ventilator) between February 2019 and November 2020 and the CLiO₂ controller (AVEA ventilator) between October 2015 and December 2018 as standard of care.

MAIN OUTCOME MEASURES

Time spent within SpO₂ target range (TR, 91-95% for either epoch) and other SpO₂ ranges.

RESULTS

Time spent within the SpO₂ TR when receiving supplemental oxygen was higher during OxyGenie control (median 71.5 [IQR 64.6-77.0]% vs 51.3 [47.3-58.5]%, p<0.001). Infants under OxyGenie control spent less time in hypoxic and hyperoxic ranges (SpO₂<80%: 0.7 [0.4-1.4]% vs 1.2 [0.7-2.3]%, p<0.001; SpO2>98%: 1.0 [0.5-2.4]% vs 4.0 [2.0-7.9]%, p<0.001). Both groups received a similar FiO₂ (29.5 [28.0-33.2]% vs 29.6 [27.7-32.1]%, p=not significant).

CONCLUSIONS

Oxygen saturation targeting was significantly different in the OxyGenie epoch in preterm infants, with less time in hypoxic and hyperoxic SpO₂ ranges during their stay in the NICU.

Closed–loop oxygen control improves oxygenation in pediatric patients under high–flow nasal oxygen—A randomized crossover study

Background

We assessed the effect of a closed–loop oxygen control system in pediatric patients receiving high–flow nasal oxygen therapy (HFNO).

Methods

A multicentre, single–blinded, randomized, and cross–over study. Patients aged between 1 month and 18 years of age receiving HFNO for acute hypoxemic respiratory failure (AHRF) were randomly assigned to start with a 2–h period of closed–loop oxygen control or a 2–h period of manual oxygen titrations, after which the patient switched to the alternative therapy. The endpoints were the percentage of time spent in predefined SpO2 ranges (primary), FiO2, SpO2/FiO2, and the number of manual adjustments.

Findings

We included 23 patients, aged a median of 18 (3–26) months. Patients spent more time in a predefined optimal SpO2 range when the closed–loop oxygen controller was activated compared to manual oxygen titrations [91⋅3% (IQR 78⋅4–95⋅1%) vs. 63⋅0% (IQR 44⋅4–70⋅7%)], mean difference [28⋅2% (95%–CI 20⋅6–37⋅8%); P &lt; 0.001]. Median FiO2 was lower [33⋅3% (IQR 26⋅6–44⋅6%) vs. 42⋅6% (IQR 33⋅6–49⋅9%); P = 0.07], but median SpO2/FiO2 was higher [289 (IQR 207–348) vs. 194 (IQR 98–317); P = 0.023] with closed–loop oxygen control. The median number of manual adjustments was lower with closed–loop oxygen control [0⋅0 (IQR 0⋅0–0⋅0) vs. 0⋅5 (IQR 0⋅0–1⋅0); P &lt; 0.001].

Conclusion

Closed-loop oxygen control improves oxygenation therapy in pediatric patients receiving HFNO for AHRF and potentially leads to more efficient oxygen use. It reduces the number of manual adjustments, which may translate into decreased workloads of healthcare providers.

Clinical trial registration

[www.ClinicalTrials.gov], identifier [NCT 05032365].

Clinical Evaluation of an Automatic Oxygen Control System for Premature Infants Receiving High-Flow Nasal Cannula for Respiratory Support: A Pilot Study

A pilot clinical study was conducted that compared the peripheral oxygen saturation (SpO2) targeting performance of an automatic oxygen control system with manual oxygen control, which is the standard of care for preterm and low birth weight infants on high-flow nasal cannula (HFNC). The new oxygen control device studied was used to automatically adjust the fraction of inspired oxygen (FiO2) according to a desired SpO2 target setpoint and measured feedback signals including the SpO2 and other signals. A crossover study was designed with several endpoints including the comparison of the percentage of time that the SpO2 was within the target range with the automatic oxygen control device versus manual oxygen control. Other metrics were also compared to assess the performance of the system including the number of bradycardia events. The pilot study included six patients that fit the inclusion criteria. The results showed that there were improvements in all of the measured outcomes considered including statistically significant improvements in the number of bradycardia events during the period when the automatic oxygen control device was used.

Automated closed–loop FiO2 titration increases the percentage of time spent in optimal zones of oxygen saturation in pediatric patients–A randomized crossover clinical trial

Introduction

We aimed to compare automated ventilation with closed–loop control of the fraction of inspired oxygen (FiO₂) to automated ventilation with manual titrations of the FiO₂ with respect to time spent in predefined pulse oximetry (SpO₂) zones in pediatric critically ill patients.

Methods

This was a randomized crossover clinical trial comparing Adaptive Support Ventilation (ASV) 1.1 with use of a closed–loop FiO₂ system vs. ASV 1.1 with manual FiO₂ titrations. The primary endpoint was the percentage of time spent in optimal SpO₂ zones. Secondary endpoints included the percentage of time spent in acceptable, suboptimal and unacceptable SpO₂ zones, and the total number of FiO₂ changes per patient.

Results

We included 30 children with a median age of 21 (11–48) months; 12 (40%) children had pediatric ARDS. The percentage of time spent in optimal SpO₂ zones increased with use of the closed–loop FiO₂ controller vs. manual oxygen control [96.1 (93.7–98.6) vs. 78.4 (51.3–94.8); P < 0.001]. The percentage of time spent in acceptable, suboptimal and unacceptable zones decreased. Findings were similar with the use of closed-loop FiO₂ controller compared to manual titration in patients with ARDS [95.9 (81.6–98.8) vs. 78 (49.5–94.8) %; P = 0.027]. The total number of closed-loop FiO₂ changes per patient was 52 (11.8–67), vs. the number of manual changes 1 (0–2), (P < 0.001).

Conclusion

In this randomized crossover trial in pediatric critically ill patients under invasive ventilation with ASV, use of a closed–loop control of FiO₂ titration increased the percentage of time spent within in optimal SpO₂ zones, and increased the total number of FiO₂ changes per patient.

Clinical trial registration

ClinicalTrials.gov, identifier: NCT04568642.

Randomised crossover trial comparing algorithms and averaging times for automatic oxygen control in preterm infants

OBJECTIVE

Automatic control (SPOC) of the fraction of inspired oxygen (FiO₂), based on continuous analysis of pulse oximeter saturation (SpO₂), improves the proportion of time preterm infants spend within a specified SpO₂-target range (Target%). We evaluated if a revised SPOC algorithm (SPOC_new, including an upper limit for FiO₂) compared to both routine manual control (RMC) and the previously tested algorithm (SPOC_old, unrestricted maximum FiO₂) increases Target%, and evaluated the effect of the pulse oximeter's averaging time on controlling the SpO₂ signal during SPOC periods.

DESIGN

Unblinded, randomised controlled crossover study comparing 2 SPOC algorithms and 2 SpO₂ averaging times in random order: 12 hours SPOC_new and 12 hours SPOC_old (averaging time 2 s or 8 s for 6 hours each) were compared with 6-hour RMC. A generated list of random numbers was used for allocation sequence.

SETTING

University-affiliated tertiary neonatal intensive care unit, Germany PATIENTS: Twenty-four infants on non-invasive respiratory support with FiO₂ >0.21 were analysed (median gestational age at birth, birth weight and age at randomisation were 25.3 weeks, 585 g and 30 days).

MAIN OUTCOME MEASURE

Target%.

RESULTS

Mean (SD) [95% CI] Target% was 56% (9) [52, 59] for RMC versus 69% (9) [65, 72] for SPOC_old__2s, 70% (7) [67, 73] for SPOC_new__2s, 71% (8) [68, 74] for SPOC_old__8s and 72% (8) [69, 75] for SPOC_new__8s.

CONCLUSIONS

Irrespective of SpO₂-averaging time, Target% was higher with both SPOC algorithms compared to RMC. Despite limiting the maximum FiO₂, SPOC_new remained significantly better at maintaining SpO₂ within target range compared to RMC.

TRIAL REGISTRATION

NCT03785899.

Frequency and duration of extreme hypoxemic and hyperoxemic episodes during manual and automatic oxygen control in preterm infants: a retrospective cohort analysis from randomized studies

Objective

Neonatal exposure to episodic hypoxemia and hyperoxemia is highly relevant to outcomes. Our goal was to investigate the differences in the frequency and duration of extreme low and high SpO₂ episodes between automated and manual inspired oxygen control.

Design

Post-hoc analysis of a cohort from prospective randomized cross-over studies.

Setting

Seven tertiary care neonatal intensive care units.

Patients

Fifty-eight very preterm neonates (32 or less weeks PMA) receiving respiratory support and supplemental oxygen participating in an automated versus manual oxygen control cross-over trial.

Main measures

Extreme hypoxemia was defined as a SpO₂ < 80%, extreme hyperoxemia as a SpO₂ > 98%. Episode duration was categorized as < 5 seconds, between 5 to < 30 seconds, 30 to < 60 seconds, 60 to < 120 seconds, and 120 seconds or longer.

Results

The infants were of a median postmenstrual age of 29 (28-31) weeks, receiving a median FiO₂ of 0.28 (0.25-0.32) with mostly receiving non-invasive respiratory support (83%). While most of the episodes were less than 30 seconds, longer episodes had a marked effect on total time exposure to extremes. The time differences in each of the three longest durations episodes (30, 60, and 120 seconds) were significantly less during automated than during manual control (p < 0.001). Nearly two-third of the reduction of total time spent at the extremes between automated and manual control (3.8 to 2.1% for < 80% SpO₂ and 3.0 to 1.6% for > 98% SpO₂) was seen in the episodes of at least 60 seconds.

Conclusions

This study shows that the majority of episodes preterm infants spent in SpO₂ extremes are of short duration regardless of manual or automated control. However, the infrequent longer episodes not only contribute the most to the total exposure, but also their reduction in frequency to the improvement associated with automated control.

Protecting the brain of the micropreemie

Advances in perinatal care have seen substantial improvements in survival without disability for extremely preterm infants. Protecting the developing brain and reducing neurodevelopmental sequelae of extremely preterm birth are strategic priorities for both research and clinical care. A number of evidence-based interventions exist for neuroprotection in micropreemies, inclusive of prevention of preterm birth and multiple births with implantation of only one embryo during in vitro fertilisation, as well as antenatal care to optimize fetal wellbeing, strategies for supporting neonatal transition, and neuroprotective developmental care. Avoidance of complications that trigger ischemia and inflammation is vital for minimizing brain dysmaturation and injury, particularly of the white matter. Neurodevelopmental surveillance, early diagnosis of cerebral palsy and early intervention are essential for optimizing long-term outcomes and quality of life. Research priorities include further evaluation of putative neuroprotective agents, and investigation of common neonatal interventions in trials adequately powered to assess neurodevelopmental outcome.

Statistical Description of SaO2–SpO2 Relationship for Model of Oxygenation in Premature Infants

A pulse oximeter model linking arterial (SaO2) and peripheral (SpO2) oxygen saturation is the terminal part of a mathematical model of neonatal oxygen transport. Previous studies have confirmed the overestimation of oxygen saturation measured by pulse oximetry in neonates compared to arterial oxygen saturation and the large variability of measured values over time caused by measurement inaccuracies. This work aimed to determine the SpO2 measurement noise that affects the biased SpO2 value at each time point and integrate the noise description with the systematic bias between SaO2 and SpO2. The SaO2–SpO2 bias was based on previously published clinical data from pathological patients younger than 60 days requiring ventilatory support. The statistical properties of the random SpO2 measurement noise were estimated from the SpO2 continuous recordings of 21 pathological and 21 physiological neonates. The result of the work is a comprehensive characterization of the properties of a pulse oximeter model describing the transfer of the input SaO2 value to the output SpO2 value, including the bias and noise typical for the bedside monitoring of neonates. These results will help to improve a computer model of neonatal oxygen transport.

Comparison of volume guarantee and volume-controlled ventilation both using closed loop inspired oxygen in preterm infants: a randomised crossover study (CLIO-VG study)

OBJECTIVE

The objective of this study was to compare two different modes of ventilation in maintaining oxygen saturation (SpO2) in target range (90%-95%) in ventilated preterm infants cared for with automatic control of oxygen delivery (A-FiO2).

DESIGN

A single-centre randomised crossover study.

SETTINGS

A level III neonatal intensive care unit.

PATIENTS

Preterm infants receiving mechanical ventilation and oxygen requirement >21%.

INTERVENTIONS

Volume guarantee (VG) vs volume controlled ventilation (VCV) modes with automatic oxygen control (A-FiO2).

OUTCOMES

The primary outcome of this study was the proportion of time spent with oxygen saturations in the target range (90%-95%) .

RESULTS

Nineteen preterm infants with a median gestation age 25 weeks (IQR: 24-28) and birth weight 685 g (IQR: 595-980) were enrolled in the study. There was no significant difference in primary outcome of median proportion of time spent in target saturation between the two arms (72% (57-81) in VG vs 75% (58-83) in VCV; p=0.98). There was no significant difference in the secondary outcomes of time spent in SpO2 <80% (0.03% vs 0.14%; p=0.51), time spent in SpO2 >98% (0.50% vs 0.08%; p=0.54), the median FiO2 (31% vs 29%; p=0.51) or manual adjustments carried out between VG and VCV, respectively. The number of episodes of prolonged hypoxaemia and hyperoxaemia were similar in the two groups.

CONCLUSION

There was no significant difference in time spent in target SpO2 range between VG and VCV when A-FiO2 was used as the FiO2 controller in this crossover randomised control study.

TRIAL REGISTRATION NUMBER

NCT03865069.

Decoupling Oxygen Tension From Retinal Vascularization as a New Perspective for Management of Retinopathy of Prematurity. New Opportunities From β-adrenoceptors

Retinopathy of prematurity (ROP) is an evolutive and potentially blinding eye disease that affects preterm newborns. Unfortunately, until now no conservative therapy of active ROP with proven efficacy is available. Although ROP is a multifactorial disease, premature exposition to oxygen concentrations higher than those intrauterine, represents the initial pathogenetic trigger. The increase of oxygenation in a retina still incompletely vascularized promotes the downregulation of proangiogenic factors and finally the interruption of vascularization (ischemic phase). However, the increasing metabolic requirement of the ischemic retina induces, over the following weeks, a progressive hypoxia that specularly increases the levels of proangiogenic factors finally leading to proliferative retinopathy (proliferative phase). Considering non-modifiable the coupling between oxygen levels and vascularization, so far, neonatologists and ophthalmologists have "played defense", meticulously searching the minimum necessary concentration of oxygen for individual newborns, refining their diagnostic ability, adopting a careful monitoring policy, ready to decisively intervene only in a very advanced stage of disease progression. However, recent advances have demonstrated the possibility to pharmacologically modulate the relationship between oxygen and vascularization, opening thus the perspective for new therapeutic or preventive opportunities. The perspective of a shift from a defensive towards an attack strategy is now at hand.

Predictive Intelligent Control of Oxygenation (PRICO) in preterm infants on high flow nasal cannula support: a randomised cross-over study

OBJECTIVE

To investigate the efficacy of automated control of inspired oxygen (FiO2) by Predictive Intelligent Control of Oxygenation (PRICO) on the Fabian ventilator in maintaining oxygen saturation (SpO2) in preterm infants on high flow nasal cannula (HFNC) support.

DESIGN

Single-centre randomised two-period crossover study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

27 preterm infants (gestational age (GA) <30 weeks) on HFNC support with FiO2 >0.25.

INTERVENTION

A 24-hour period on automated FiO2-control with PRICO compared with a 24-hour period on routine manual control (RMC) to maintain a SpO2 level within target range of 88%-95% measured at 30 s intervals.

MAIN OUTCOME MEASURES

Primary outcome: time spent within target range (88%-95%).

SECONDARY OUTCOMES

time spent above and below target range, in severe hypoxia (SpO2 <80%) and hyperoxia (SpO2 >98%), mean SpO2 and FiO2 and manual FiO2 adjustments.

RESULTS

15 patients received PRICO-RMC and 12 RMC-PRICO. The mean time within the target range increased with PRICO: 10.8% (95% CI 7.6 to 13.9). There was a decrease in time below target range: 7.6% (95% CI 4.2 to 11.0), above target range: 3.1% (95% CI 2.9 to 6.2) and in severe hypoxia: 0.9% (95% CI 1.5 to 0.2). We found no difference in time spent in severe hyperoxia. Mean FiO2 was higher during PRICO: 0.019 (95% CI 0.006 to 0.030). With PRICO there was a reduction of manual adjustments: 9/24 hours (95% CI 6 to 12).

CONCLUSION

In preterm infants on HFNC support, automated FiO2-control by PRICO is superior to RMC in maintaining SpO2 within target range. Further validation studies with a higher sample frequency and different ventilation modes are needed.

The relationship between intermittent hypoxemia events and neural outcomes in neonates

This brief review examines 1) patterns of intermittent hypoxemia in extremely preterm infants during early postnatal life, 2) the relationship between neonatal intermittent hypoxemia exposure and outcomes in both human and animal models, 3) potential mechanistic pathways, and 4) future alterations in clinical care that may reduce morbidity. Intermittent hypoxemia events are pervasive in extremely preterm infants (<28 weeks gestation at birth) during early postnatal life. An increased frequency of intermittent hypoxemia events has been associated with a range of poor neural outcomes including language and cognitive delays, motor impairment, retinopathy of prematurity, impaired control of breathing, and intraventricular hemorrhage. Neonatal rodent models have shown that exposure to short repetitive cycles of hypoxia induce a pathophysiological cascade. However, not all patterns of intermittent hypoxia are deleterious and some may even improve neurodevelopmental outcomes. Therapeutic interventions include supplemental oxygen, pressure support and pharmacologic drugs but prolonged hyperoxia and pressure exposure have been associated with cardiopulmonary morbidity. Therefore, it becomes imperative to distinguish high risk from neutral and/or even beneficial patterns of intermittent hypoxemia during early postnatal life. Identification of such patterns could improve clinical care with targeted interventions for high-risk patterns and minimal or no exposure to treatment modalities for low-risk patterns.

Evidence for the Management of Bronchopulmonary Dysplasia in Very Preterm Infants

BACKGROUND

Very preterm birth often results in the development of bronchopulmonary dysplasia (BPD) with an inverse correlation of gestational age and birthweight. This very preterm population is especially exposed to interventions, which affect the development of BPD.

OBJECTIVE

The goal of our review is to summarize the evidence on these daily procedures and provide evidence-based recommendations for the management of BPD.

METHODS

We conducted a systematic literature research using MEDLINE/PubMed on antenatal corticosteroids, surfactant-replacement therapy, caffeine, ventilation strategies, postnatal corticosteroids, inhaled nitric oxide, inhaled bronchodilators, macrolides, patent ductus arteriosus, fluid management, vitamin A, treatment of pulmonary hypertension and stem cell therapy.

RESULTS

Evidence provided by meta-analyses, systematic reviews, randomized controlled trials (RCTs) and large observational studies are summarized as a narrative review.

DISCUSSION

There is strong evidence for the use of antenatal corticosteroids, surfactant-replacement therapy, especially in combination with noninvasive ventilation strategies, caffeine and lung-protective ventilation strategies. A more differentiated approach has to be applied to corticosteroid treatment, the management of patent ductus arteriosus (PDA), fluid-intake and vitamin A supplementation, as well as the treatment of BPD-associated pulmonary hypertension. There is no evidence for the routine use of inhaled bronchodilators and prophylactic inhaled nitric oxide. Stem cell therapy is promising, but should be used in RCTs only.

Automated versus manual oxygen control in preterm infants receiving respiratory support: a systematic review and meta-analysis

BACKGROUND

Ventilated preterm infants are exposed to deviations from the intended arterial oxygen saturation range. Therefore, an automated control system was developed to rapidly modulate the fraction of inspired oxygen. The aim of this review is to compare the efficacy and safety of automated versus manual oxygen delivery control.

METHODS

In December 2020, we systematically searched four electronic databases; PubMed, Cochrane Library, Scopus, and Web of Science for eligible randomized controlled trials. We extracted and pooled data as mean difference and 95% confidence interval in an inverse variance method using RevMan software.

RESULTS

Thirteen trials were included in this systematic review and meta-analysis, enrolling 343 preterm infants on respiratory support. Automated oxygen control increased the time spent within the target arterial oxygen saturation range of 85-96% (MD = 8.96; 95% CI [6.26, 11.67], p<.00001), and 90-95% (MD = 18.25; 95% CI [4.58, 31.65], p = .008). In addition, it reduced the time of hypoxia (<80%); (MD = -1.24; 95% CI [-2.05, -0.43], p = .003), (MD = -0.82; 95% CI [-1.23, -0.41], p<.0001) with predetermined ranges of 85-96% and 90-95%, respectively. Automated control system reduced as well the time of hyperoxia (>98%) (MD = -0.99; 95% CI [-1.74, -0.25], p = .009) at intended range of 90-95%, and number of manual inspired oxygen fraction adjustments (MD = -2.82; 95% CI [-4.56, -1.08], p = .002).

CONCLUSIONS

Automated oxygen delivery is rapid and effective in controlling infants' oxygen saturation. It can be used to reduce the load over the nurses, but not to substitute the clinical supervision. Further long-term trials of large-scale are required to evaluate the prolonged clinical outcomes.

Automated control of fraction of inspired oxygen: is it time for widespread adoption?

PURPOSE OF REVIEW

Over the past two decades, numerous algorithms for automated control of the fraction of inspired oxygen (FiO2) have been developed and incorporated into contemporary neonatal ventilators and high-flow devices in an attempt to optimize supplemental oxygen therapy in preterm infants. This review explores whether current evidence is sufficient to recommend widespread adoption of automated oxygen control in neonatal care.

RECENT FINDINGS

To date, 15 studies have compared automated versus manual control of FiO2 in preterm infants on respiratory support. This includes four new randomized cross-over trials published in the last 2 years. Available evidence consistently demonstrates a significant improvement in time spent within the target saturation range with automated FiO2 control. There are fewer episodes of severe hypoxemia and fewer manual FiO2 adjustments with automated oxygen control. Nursing workload may be reduced. However, no currently completed studies report on clinical outcomes, such as chronic lung disease or retinopathy of prematurity.

SUMMARY

Automated oxygen control appears to be a reasonable option for FiO2 titration in preterm infants on respiratory support, if resources are available, and might substantially reduce nursing workload. Further randomized clinical trials to explore its effects on clinical outcomes are required.

Automated oxygen control in preterm infants, how does it work and what to expect: a narrative review

BACKGROUND

Automated oxygen control systems are finding their way into contemporary ventilators for preterm infants, each with its own algorithm, strategy and effect.

OBJECTIVE

To provide guidance to clinicians seeking to comprehend automated oxygen control and possibly introduce this technology in their practice.

METHOD

A narrative review of the commercially available devices using different algorithms incorporating rule-based, proportional-integral-derivative and adaptive concepts are described and explained. An overview of how they work and, if available, the clinical effect is given.

RESULTS

All algorithms have shown a beneficial effect on the proportion of time that oxygen saturation is within target range, and a decrease in hyperoxia and severe hypoxia. Automated oxygen control may also reduce the workload for bedside staff. There is concern that such devices could mask clinical deterioration, however this has not been reported to date.

CONCLUSIONS

So far, trials involving different algorithms are heterogenous in design and no head-to-head comparisons have been made, making it difficult to differentiate which algorithm is most effective and what clinicians can expect from algorithms under certain conditions.

Is faster better? A randomised crossover study comparing algorithms for closed-loop automatic oxygen control

OBJECTIVE

Closed-loop automatic control (CLAC) of the fractional inspired oxygen (FiO₂) improved oxygen administration to preterm infants on respiratory support. We investigated whether a revised CLAC algorithm (CLAC_fast, ≤2 FiO₂ adjustments/min), compared with routine manual control (RMC_only), increased the proportion of time with arterial haemoglobin oxygen saturation measured by pulse oximetry within prespecified target ranges (Target%) while not being inferior to the original algorithm (CLAC_slow: ≤0.3 FiO₂ adjustments/min).

DESIGN

Unblinded randomised controlled crossover study comparing three modes of FiO₂ control in random order for 8 hours each: RMC supported by CLAC_fast was compared with RMC_only and RMC supported by CLAC_slow. A computer-generated list of random numbers using a block size of six was used for the allocation sequence.

SETTING

Two German tertiary university neonatal intensive care units.

PATIENTS

Of 23 randomised patients, 19 were analysed (mean±SD gestational age 27±2 weeks; age at randomisation 24±10 days) on non-invasive (n=18) or invasive (n=1) respiratory support at FiO₂ >0.21.

MAIN OUTCOME MEASURE

Target%.

RESULTS

Mean±SD [95% CI] Target% was 68%±11% [65% to 71%] for CLAC_fast versus 65%±11% [61% to 68%] for CLAC_slow versus 58%±11% [55% to 62%] for RMC_only. Prespecified hypothesis tests of: (A) superiority of CLAC_fast versus RMC_only and (B) non-inferiority of CLAC_fast versus CLAC_slow with margin of 5% yielded one-sided p values of <0.001 for both comparisons.

CONCLUSIONS

This revised and faster CLAC algorithm was still superior to routine care in infants on respiratory support and not inferior to a previously tested slower algorithm.

TRIAL REGISTRATION NUMBER

NCT03163108.

Closed loop automated oxygen control in neonates-A review

AIM

Neonates frequently require supplementary oxygen but may develop complications if the oxygen saturation is outside the target range. This review aimed to determine whether the algorithms used in closed loop automated oxygen control systems influenced their efficacy and whether use of the systems reduced relevant, long-term neonatal complications.

METHODS

A literature search was conducted using PubMed and Google Scholar. The search terms were 'closed loop' or 'automat*', 'oxygen' and 'neonat*'.

RESULTS

Eighteen studies were identified: sixteen comparison clinical studies, an observational study and an animal study. Overall, closed loop automated oxygen control was associated with an increased percentage of time spent within the target oxygen saturation range and there were fewer manual adjustments to the inspired oxygen concentration when compared with manual oxygen control. The systems were effective in infants on non-invasive respiratory support or mechanically ventilated, but no study included term-born infants. No long-term data were available to determine if complications of oxygen toxicity were reduced.

CONCLUSION

Closed loop automated oxygen control has been shown in short term trials including preterm and low birth weight infants to improve target saturation achievement. Whether long-term outcomes will be improved with their use requires investigation.

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

OBJECTIVE

To evaluate the effectiveness of intermittent pulse oximetry in guiding oxygen therapy in neonates in a low-resource setting.

DESIGN AND SETTING

Prospective validation study at three hospitals in southwest Nigeria. We performed concealed continuous pulse oximetry on participants to evaluate intermittent SpO₂ monitoring.

PATIENTS

We recruited all preterm or low birthweight neonates, and all term neonates who required oxygen therapy, who were admitted to the neonatal ward(s) of the study hospitals during the study period.

MAIN OUTCOME MEASURES

Proportion of time preterm/low birthweight neonates on oxygen spent within, above and below the target SpO₂ range of 90%-95%; and the proportion of time term neonates and neonates not on oxygen spent within and below the target range of 90%-100%.

RESULTS

Preterm/low birthweight neonates receiving oxygen therapy (group A) spent 15.7% (95% CI 13.3 to 18.9) of time in the target SpO₂ range of 90%-95%. They spent 75.0% (63.6-81.1) of time above 95%, and 2.7% (1.7-5.6) of time below 85%. Term neonates and all neonates not receiving oxygen (group B) spent 97.3% (95% CI 96.4 to 98.6) of time within the target range of 90%-100%, and 0.9% (0.3-1.4) of time below 85%. Guidelines recommended SpO₂ monitoring 3 times per day for all patients, however neonates in groups A and B were monitored an average of 4.7 and 5.3 times per day, respectively.

CONCLUSIONS

To better maintain SpO₂ within the target range, preterm/low birthweight neonates on oxygen should have their SpO₂ monitored more frequently than the current 4.7 times per day. In all other neonates, however, monitoring SpO₂ 5.3 times per day appears suitable.

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

PURPOSE

To 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 METHODS

Cross-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).

RESULTS

328 (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_. CONCLUSIONS: The 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 IMPLICATIONS

A 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.

Effects of closed-loop automatic control of the inspiratory fraction of oxygen (FiO2-C) on outcome of extremely preterm infants - study protocol of a randomized controlled parallel group multicenter trial for safety and efficacy

BACKGROUND

Most extremely low gestational age neonates (ELGANS, postmenstrual age at birth (PMA) < 28 completed weeks) require supplemental oxygen and experience frequent intermittent hypoxemic and hyperoxemic episodes. Hypoxemic episodes and exposure to inadequately high concentrations of oxygen are associated with an increased risk of retinopathy of prematurity (ROP), chronic lung disease of prematurity (BPD), necrotizing enterocolitis (NEC), neurodevelopmental impairment (NDI), and death beyond 36 weeks PMA. Closed-loop automated control of the inspiratory fraction of oxygen (FiO2-C) reduces time outside the hemoglobin oxygen saturation (SpO2) target range, number and duration of hypo- and hyperoxemic episodes and caregivers' workload. Effects on clinically important outcomes in ELGANs such as ROP, BPD, NEC, NDI and mortality have not yet been studied.

METHODS

An outcome-assessor-blinded, randomized controlled, parallel-group trial was designed and powered to study the effect of FiO2-C (in addition to routine manual control (RMC) of FiO2), compared to RMC only, on death and severe complications related to hypoxemia and/or hyperoxemia. 2340 ELGANS with a GA of 23 + 0/7 to 27 + 6/7 weeks will be recruited in approximately 75 European tertiary care neonatal centers. Study participants are randomly assigned to RMC (control-group) or FiO2-C in addition to RMC (intervention-group). Central randomization is stratified for center, gender and PMA at birth (< 26 weeks and ≥ 26 weeks). FiO2-C is provided by commercially available and CE-marked ventilators with an FiO2-C algorithm intended for use in newborn infants. The primary outcome variable (composite of death, severe ROP, BPD or NEC) is assessed at 36 weeks PMA (or, in case of ROP, until complete vascularization of the retina, respectively). The co-primary outcome variable (composite outcome of death, language/cognitive delay, motor impairment, severe visual impairment or hearing impairment) is assessed at 24 months corrected age.

DISCUSSION

Short-term studies on FiO2-C showed improved time ELGANs spent within their assigned SpO2 target range, but effects of FiO2-C on clinical outcomes are yet unknown and will be addressed in the FiO2-C trial. This will ensure an appropriate assessment of safety and efficacy before FiO2-C may be implemented as standard therapy.

TRIAL REGISTRATION

The study is registered at www.ClinicalTrials.gov: NCT03168516 , May 30, 2017.

New Methods for Noninvasive Oxygen Administration

Oxygen therapy is an essential part of neonatal care. Targeting oxygen saturations and preventing hypoxemia and hyperoxemia is difficult, particularly in preterm infants. The mode of oxygen delivery directly affects the stability of oxygen saturations, hypoxemia, and hyperoxemia. This stability has important clinical implications. New methods of noninvasive oxygen administration, including closed-loop automated control and servo-controlled oxygen environments, have been developed to improve oxygen saturation targeting and decrease episodes of hyperoxemia and hypoxemia.

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

Background

Changes 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.

Methods

An 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.

Results

During 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%).

Conclusions

In 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 registration

Retrospectively registered 15 May 2018 at ISRCTN (49239883).

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1496-5) contains supplementary material, which is available to authorized users.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome - 2019 Update

As management of respiratory distress syndrome (RDS) advances, clinicians must continually revise their current practice. We report the fourth update of "European Guidelines for the Management of RDS" by a European panel of experienced neonatologists and an expert perinatal obstetrician based on available literature up to the end of 2018. Optimising outcome for babies with RDS includes prediction of risk of preterm delivery, need for appropriate maternal transfer to a perinatal centre and timely use of antenatal steroids. Delivery room management has become more evidence-based, and protocols for lung protection including initiation of CPAP and titration of oxygen should be implemented immediately after birth. Surfactant replacement therapy is a crucial part of management of RDS, and newer protocols for its use recommend early administration and avoidance of mechanical ventilation. Methods of maintaining babies on non-invasive respiratory support have been further developed and may cause less distress and reduce chronic lung disease. As technology for delivering mechanical ventilation improves, the risk of causing lung injury should decrease, although minimising time spent on mechanical ventilation using caffeine and, if necessary, postnatal steroids are also important considerations. Protocols for optimising general care of infants with RDS are also essential with good temperature control, careful fluid and nutritional management, maintenance of perfusion and judicious use of antibiotics all being important determinants of best outcome.

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.