Rationale: Supplemental oxygen is widely administered to ICU patients, but appropriate oxygenation targets remain unclear.Objectives: This study aimed to determine whether a low-oxygenation... Show moreRationale: Supplemental oxygen is widely administered to ICU patients, but appropriate oxygenation targets remain unclear.Objectives: This study aimed to determine whether a low-oxygenation strategy would lower 28-day mortality compared with a high-oxygenation strategy.Methods: This randomized multicenter trial included mechanically ventilated ICU patients with an expected ventilation duration of at least 24 hours. Patients were randomized 1:1 to a low-oxygenation (Pa-O2, 55-80mmHg; or oxygen saturation as measured by pulse oximetry, 91-94%) or high-oxygenation (Pa-O2, 110-150mmHg; or oxygen saturation as measured by pulse oximetry, 96-100%) target until ICU discharge or 28 days after randomization, whichever came first. The primary outcome was 28-day mortality. The study was stopped prematurely because of the COVID-19 pandemic when 664 of the planned 1,512 patients were included.Measurements and Main Results: Between November 2018 and November 2021, a total of 664 patients were included in the trial: 335 in the low-oxygenation group and 329 in the high-oxygenation group. The median achieved Pa-O2 was 75mmHg (interquartile range, 70-84) and 115mmHg (interquartile range, 100-129) in the low- and high-oxygenation groups, respectively. At Day 28, 129 (38.5%) and 114 (34.7%) patients had died in the low- and high-oxygenation groups, respectively (risk ratio, 1.11; 95% confidence interval, 0.9-1.4; P = 0.30). At least one serious adverse event was reported in 12 (3.6%) and 17 (5.2%) patients in the low- and high-oxygenation groups, respectively.Conclusions: Among mechanically ventilated ICU patients with an expected mechanical ventilation duration of at least 24 hours, using a low-oxygenation strategy did not result in a reduction of 28-day mortality compared with a high-oxygenation strategy. Show less
Nusman, C.M.; Schalij-Delfos, N.E.; Groenwold, R.H.H.; Onland, W. 2022
Strategies to ensure high intraocular oxygen delivery to the developing retina after 32 weeks gestational age, such as higher saturation targets and/or higher hemoglobin levels, are hypothesized to... Show moreStrategies to ensure high intraocular oxygen delivery to the developing retina after 32 weeks gestational age, such as higher saturation targets and/or higher hemoglobin levels, are hypothesized to prevent ophthalmological treatment for retinopathy of prematurity (ROP). This short report summarizes the current evidence of these strategies, and discusses possibilities of future studies. A large sample size would be required and therefore the feasibility of a future randomized controlled trial is questioned. Show less
Background: The initial FiO(2) that should be used for the stabilization of preterm infants in the delivery room (DR) is still a matter of debate as both hypoxia and hyperoxia should be prevented.... Show moreBackground: The initial FiO(2) that should be used for the stabilization of preterm infants in the delivery room (DR) is still a matter of debate as both hypoxia and hyperoxia should be prevented. A recent randomized controlled trial showed that preterm infants [gestational age (GA) < 30 weeks] stabilized with an initial high FiO(2) (1.0) had a significantly higher breathing effort than infants stabilized with a low FiO(2) (0.3). As the diaphragm is the main respiratory muscle in these infants, we aimed to describe the effects of the initial FiO(2) on diaphragm activity.Methods: In a subgroup of infants from the original bi-center randomized controlled trial diaphragm activity was measured with transcutaneous electromyography of the diaphragm (dEMG), using three skin electrodes that were placed directly after birth. Diaphragm activity was compared in the first 5 min after birth. From the dEMG respiratory waveform several outcome measures were determined for comparison of the groups: average peak- and tonic inspiratory activity (dEMG(peak) and dEMG(ton), respectively), inspiratory amplitude (dEMG(amp)), area under the curve (dEMG(AUC)) and the respiratory rate (RR).Results: Thirty-one infants were included in this subgroup, of which 29 could be analyzed [n = 15 (median GA 28.4 weeks) and n = 14 (median GA 27.9 weeks) for the 100 and 30% oxygen group, respectively]. Tonic diaphragm activity was significantly higher in the high FiO(2)-group (4.3 +/- 2.1 mu V vs. 2.9 +/- 1.1 mu V; p = 0.047). The other dEMG-parameters (dEMG(peak), dEMG(amp), dEMG(AUC)) showed consistently higher values in the high FiO(2) group, but did not reach statistical significance. Average RR showed similar values in both groups (34 +/- 9 vs. 32 +/- 10 breaths/min for the high and low oxygen group, respectively).Conclusion: Preterm infants stabilized with an initial high FiO(2) showed significantly more tonic diaphragm activity and an overall trend toward a higher level of diaphragm activity than those stabilized with an initial low FiO(2). These results confirm that a high initial FiO(2) after birth stimulates breathing effort, which can be objectified with dEMG. Show less
Grim, C.C.A.; Helmerhorst, H.J.F.; Schultz, M.J.; Winters, T.; Voort, P.H.J. van der; Westerloo, D.J. van; Jonge, E. de 2020
BACKGROUND: Little is known to what extent attitudes of ICU clinicians are influenced by new insights and recommendations to be more conservative with oxygen therapy. Our aim was to investigate... Show moreBACKGROUND: Little is known to what extent attitudes of ICU clinicians are influenced by new insights and recommendations to be more conservative with oxygen therapy. Our aim was to investigate whether implementation of a conservative oxygenation guideline structurally changed self-reported attitudes and actual clinical practice. METHODS: After the implementation of a conservative oxygen therapy guideline in 3 teaching hospitals in the Netherlands, ICU clinicians were surveyed regarding their attitudes toward oxygen therapy. The survey results were compared with survey results taken before the introduction of the new guideline. Arterial blood gas analysis data and ventilator settings were retrieved from all patients admitted to the participating ICUs in the studied period, and changes after implementing the guideline were assessed. RESULTS: In total, 180 ICU clinicians returned the survey. Compared to before implementation of a conservative oxygen guideline, more clinicians chose a preferred P-aO2 and an oxygen saturation measured from an arterial sample (S-aO2) limit after implementation of the guideline. In general, clinicians reported a more conservative approach toward management of F(IO2 )and less frequently increased the F-IO2. In the period after the active implementation of the guideline, 5,840 subjects were admitted to the participating ICUs and 101,869 arterial blood gas analyses were retrieved. Actual practice changed with overall lower oxygenation levels (median P-aO2 77.93 mm Hg, compared to 86.93 mm Hg before implementation) of arterial blood and a decrease of PEEP and F-IO2. CONCLUSIONS: Implementing a conservative oxygenation guideline was an effective method that changed self-reported attitudes and actual clinical practice and improved adherence to conservative oxygenation targets in a short period of time. Show less
High resolution solar spectra have permitted the measurement with great accuracy of equivalent widths of vibration-rotation lines of OH in the X2Pi state near 3-micron wavelength. Using recent... Show moreHigh resolution solar spectra have permitted the measurement with great accuracy of equivalent widths of vibration-rotation lines of OH in the X2Pi state near 3-micron wavelength. Using recent theoretical results for the transition probabilities, a solar oxygen abundance of (8.93 + or - 0.02) is derived which is in perfect agreement with the abundance deduced from the OH pure rotation lines. The solar abundance of oxygen is therefore A(O) = 8.92 + or - 0.035, as inferred from the analysis of 43 vibration-rotation lines and 81 pure rotation lines of the OH molecule. It is confirmed that the dipole moment function of Werner, Rosmus and Reinsch (1983) together with the Holweger-Mueller (1974) solar atmosphere model are to be preferred in the analysis of the data. Show less
