SpO2 Range Research Articles

A randomised crossover trial of closed loop automated oxygen control in preterm, ventilated infants.

To determine whether closed loop automated oxygen control resulted in a reduction in the duration and severity of desaturation episodes and the number of blood gases and chest radiographs in preterm, ventilated infants. Infants were studied on two consecutive days for 12hours on each day. They were randomised to receive standard care (standard period) or standard care with a closed loop automated oxygen control system (automated oxygen control period) first. Twenty-four infants with a median gestational age of 25.7 (range 23.1-32.6) weeks were studied at a median postconceptional age of 27.4 (range 24.3-34.9) weeks. During the automated oxygen control period, there were fewer desaturations that lasted >30seconds (P=.032) or >60seconds (P=.002), infants spent a higher proportion of the time within their target SpO2 range during the automated oxygen control period (P<.001), and fewer manual adjustments were made to the inspired oxygen concentration (mean 0.58 vs mean 11.29) (P<.001). There were no significant differences in the number of blood gases (P=.872) or chest radiographs (P=.366) between the two periods. Closed loop automated oxygen delivery resulted in fewer prolonged desaturations with more time spent in the targeted oxygen range.

Automatic oxygen flow titration in spontaneously breathing children: An open-label randomized controlled pilot study.

When children require supplemental oxygen due to acute hypoxemic respiratory distress (AHRD), manual control of the oxygen flow is often difficult and time-consuming, and carries the risk of unrecognized hypoxia and hyperoxia. To date, no automatic oxygen titration system has been developed and evaluated in spontaneously breathing children. Children between 1 month and 15 years of age receiving supplemental oxygen due to AHRD were recruited within 24 hours following the onset of the O2 administration in a French University Department of Paediatrics. Patients were randomized to receive either automated oxygen administration using the FreeO2 device, or conventional manual oxygen administration over a maximum period of 6 hours. Stratification was performed to classify the patients into two age groups: 1 month to 2 years of age and 2 to 15 years of age. The primary outcome was % time spent within the SpO2 target range (92%-98%). 60 patients (30 infants, 30 children) were randomized and 55 could be analyzed for the primary outcome (28 automated, 27 manual). The automated O2 delivery using the FreeO2 device significantly increased the time spent within the predefined SpO2 range (94.6% ± 6% vs 76.3% ± 22%, difference [95% confidence interval {CI}] 18.4 [10.1; 26.7]) with less time spent with hypoxemia (1% ± 1.1% vs 15.1% ± 21.8%, difference [95% CI] -14.4 [-22.2; -6.7]). This difference was greater among (2-15 years of age) children, compared to (1 month-2 years of age) infants. The present randomized controlled pilot study indicates that the tested automated closed-loop O2 titration technology was safe and yielded improved oxygen parameters among spontaneously breathing children. Based on our pilot data, a full randomized controlled trial will be required to verify the potential clinical benefits.

Evaluation of an enhanced pulse oximeter auditory display: a simulation study

BackgroundWe compared anaesthetists' ability to identify haemoglobin oxygen saturation (SpO2) levels using two auditory displays: one based on a standard pulse oximeter display (varying pitch plus alarm) and the other enhanced with additional sound properties (varying pitch plus tremolo and acoustic brightness) to differentiate SpO2 ranges. MethodsIn a counter-balanced crossover study in a simulator, 20 experienced anaesthetists supervised a junior colleague (an actor) managing two airway surgery scenarios: once while using the enhanced auditory display and once while using a standard auditory display. Participants were distracted with other tasks such as paperwork and workplace interruptions, but were required to identify when SpO2 transitioned between pre-set ranges (target, low, critical) and when other vital signs transitioned out of a target range. They also identified the range once a transition had occurred. Visual displays were available for all monitored vital signs, but the numerical value for SpO2 was excluded. ResultsParticipants were more accurate and faster at detecting transitions to and from the target SpO2 range when using the enhanced display (100.0%, 3.3 s) than when using the standard display plus alarm (73.2%, 27.4 s) (P<0.001 and P=0.004, respectively). They were also more accurate at identifying the SpO2 range once a transition had occurred when using the enhanced display (100.0%) than when using the standard display plus alarm (57.1%; P<0.001). ConclusionsThe enhanced auditory display helps anaesthetists judge SpO2 levels more effectively than current auditory displays and may facilitate ‘eyes-free’ monitoring.

Optimal Oxygen Targets in Term Lambs with Meconium Aspiration Syndrome and Pulmonary Hypertension.

Optimal oxygen saturation as measured by pulse oximetry (SpO2) in neonatal lung injury, such as meconium aspiration syndrome (MAS) and persistent pulmonary hypertension of newborn (PPHN), is not known. Our goal was to determine the SpO2 range in lambs with MAS and PPHN that results in the highest brain oxygen delivery (bDO2) and pulmonary blood flow (Qp) and the lowest pulmonary vascular resistance and oxidative stress. Meconium was instilled into endotracheal tubes in 25 near-term gestation lambs, and the umbilical cord was occluded to induce asphyxia and gasping, causing MAS and PPHN. Lambs were randomized into four groups and ventilated for 6 hours with fixed fraction of inspired oxygen (FiO2) = 1.0 irrespective of SpO2, and three groups had FiO2 titrated to keep preductal SpO2 between 85% and 89%, 90% and 94%, and 95% and 99%, respectively. Tissues were collected to measure nitric oxide synthase activity, 3-nitrotyrosine, and 8-isoprostanes. Throughout the 6-hour exposure period, lambs in the 95-99% SpO2 target group had the highest Qp, lowest pulmonary vascular resistance, and highest bDO2 but were exposed to higher FiO2 (0.5 ± 0.21 vs. 0.29 ± 0.17) with higher lung 3-nitrotyrosine (0.67 [interquartile range (IQR), 0.43-0.73] ng/mcg protein vs. 0.1 [IQR, 0.09-0.2] ng/mcg protein) and lower lung nitric oxide synthase activity (196 [IQR, 192-201] mMol nitrite/mg protein vs. 270 [IQR, 227-280] mMol nitrite/mg protein) compared with the 90-94% target group. Brain 3-nitrotyrosine was lower in the 85-89% target group, and brain/lung 8-isoprostane levels were not significantly different. In term lambs with MAS and PPHN, Qp and bDO2 through the first 6 hours are higher with target SpO2 in the 95-99% range. However, the 90-94% target range is associated with significantly lower FiO2 and lung oxidative stress. Clinical trials comparing the 90-94% versus the 95-99% SpO2 target range in term infants with PPHN are warranted.

Thresholds for oximetry alarms and target range in the NICU: an observational assessment based on likely oxygen tension and maturity

BackgroundContinuous monitoring of SpO2 in the neonatal ICU is the standard of care. Changes in SpO2 exposure have been shown to markedly impact outcome, but limiting extreme episodes is an arduous task. Much more complicated than setting alarm policy, it is fraught with balancing alarm fatigue and compliance. Information on optimum strategies is limited.MethodsThis is a retrospective observational study intended to describe the relative chance of normoxemia, and risks of hypoxemia and hyperoxemia at relevant SpO2 levels in the neonatal ICU. The data, paired SpO2-PaO2 and post-menstrual age, are from a single tertiary care unit. They reflect all infants receiving supplemental oxygen and mechanical ventilation during a 3-year period. The primary measures were the chance of normoxemia (PaO2 50–80 mmHg), risks of severe hypoxemia (PaO2 ≤ 40 mmHg), and of severe hyperoxemia (PaO2 ≥ 100 mmHg) at relevant SpO2 levels.ResultsNeonates were categorized by postmenstrual age: < 33 (n = 155), 33–36 (n = 192) and > 36 (n = 1031) weeks.From these infants, 26,162 SpO2-PaO2 pairs were evaluated. The post-menstrual weeks (median and IQR) of the three groups were: 26 (24–28) n = 2603; 34 (33–35) n = 2501; and 38 (37–39) n = 21,058. The chance of normoxemia (65, 95%-CI 64–67%) was similar across the SpO2 range of 88–95%, and independent of PMA. The increasing risk of severe hypoxemia became marked at a SpO2 of 85% (25, 95%-CI 21–29%), and was independent of PMA. The risk of severe hyperoxemia was dependent on PMA. For infants < 33 weeks it was marked at 98% SpO2 (25, 95%-CI 18–33%), for infants 33–36 weeks at 97% SpO2 (24, 95%-CI 14–25%) and for those > 36 weeks at 96% SpO2 (20, 95%-CI 17–22%).ConclusionsThe risk of hyperoxemia and hypoxemia increases exponentially as SpO2 moves towards extremes. Postmenstrual age influences the threshold at which the risk of hyperoxemia became pronounced, but not the thresholds of hypoxemia or normoxemia. The thresholds at which a marked change in the risk of hyperoxemia and hypoxemia occur can be used to guide the setting of alarm thresholds. Optimal management of neonatal oxygen saturation must take into account concerns of alarm fatigue, staffing levels, and FiO2 titration practices.

Designing a Remote Closed-Loop Automatic Oxygen Control in Preterm Infants

Background: Different automated systems have been developed to improve the maintenance of target range of arterial oxygen saturation (SPO2) in premature infants with respiratory distress. Objectives: This study aimed to develop a remote closed-loop automatic oxygen control (RCLAC) as an efficient monitoring device. Then the means of the fraction of inspired oxygen (FIO2) and SPO2 by routine manual control (RMC) and RCLAC were compared. Methods: A developmental-descriptive study was carried out in an Iranian hospital (Tehran, Iran; 2015 - 2017). Twenty-two preterm infants with gestational age 24 - 28 weeks entered the study. A database was prepared based on pulse oximeter parameters. A Wi-Fi module was implemented to receive data from a pulse oximeter and send inputs to the user’s mobile. Vibrate alarm was implemented for high or low FIO2. After receiving notifications associated with an increase or decrease of FIO2 levels and user’s confirmation; the alterations were applied on the ventilator. Results: The mean FIO2 in the RMC system was significantly higher than the RCLAC system (98.1 ± 2.67 vs 79.5 ± 16.03; P = 0.0001). According to the results, when the SPO2 reached close to target SPO2 range and consequently FIO2 changed (decreased or increased based on target SPO2), heart rate showed a regular beating with a decrease in the numbers. Conclusions: Remote closed-loop automatic oxygen control system as a simple device could prevent preterm neonates from sustained hypo-hyperoxemic and arrhythmia episodes. Moreover, by using RCLAC, there was no need for continuous monitoring that may reduce the workload of NICU medical staff. Collecting reliable data and recording information in digital forms were also other benefits. Further studies with larger sample size are strongly suggested.

Pulse oximetry based on photoplethysmography imaging with red and green light

Remotely measuring the arterial blood oxygen saturation (SpO2) in visible light (Vis) involves different probing depths, which may compromise calibratibility. This paper assesses the feasibility of calibrating camera-based SpO2 (SpO2,cam) using red and green light. Camera-based photoplethysmographic (PPG) signals were measured at 46 healthy adults at center wavelengths of 580 nm (green), 675 nm (red), and 840 nm (near-infrared; NIR). Subjects had their faces recorded during normoxia and hypoxia and under gradual cooling. SpO2,cam estimates in Vis were based on the normalized ratio of camera-based PPG amplitudes in red over green light (RoG). SpO2,cam in Vis was validated against contact SpO2 (reference) and compared with SpO2,cam estimated using red-NIR wavelengths. An RoG-based calibration curve for SpO2 was determined based on data with a SpO2 range of 85-100%. We found an [Formula: see text] error of 2.9% (higher than the [Formula: see text] for SpO2,cam in red-NIR). Additional measurements on normoxic subjects under temperature cooling (from [Formula: see text] to [Formula: see text]) evidenced a significant bias of -1.7, CI [-2.7,-0.7]%. It was also noted that SpO[Formula: see text] estimated at the cheeks was significantly biased (-3.6, CI[-5.7,-1.5]%) with respect to forehead estimations. Under controlled conditions, SpO[Formula: see text] can be calibrated with red and green light but the accuracy is less than that of SpO[Formula: see text] estimated in the usual red-NIR window.

The Search for Optimal Oxygen Saturation Targets in Critically Ill Patients: Observational Data From Large ICU Databases

Although low oxygen saturations are generally regarded as deleterious, recent studies in ICU patients have shown that a liberal oxygen strategy increases mortality. However, the optimal oxygen saturation target remains unclear. The goal of this study was to determine the optimal range by using real-world data. Replicate retrospective analyses were conducted of two electronic medical record databases: the eICU Collaborative Research Database (eICU-CRD) and the Medical Information Mart for Intensive Care III database (MIMIC). Only patients with at least 48h of oxygen therapy were included. Nonlinear regression was used to analyze the association between median pulse oximetry-derived oxygen saturation (Spo2) and hospital mortality. We derived an optimal range of Spo2 and analyzed the association between the percentage of time within the optimal range of Spo2 and hospital mortality. All models adjusted for age, BMI, sex, and Sequential Organ Failure Assessment score. Subgroup analyses included ICU types, main diagnosis, and comorbidities. The analysis identified 26,723 patients from eICU-CRD and 8,564 patients from MIMIC. The optimal range of Spo2 was 94%to 98%in both databases. The percentage of time patients were within the optimal range of Spo2 was associated with decreased hospital mortality (OR of 80%vs40%of the measurements within the optimal range, 0.42 [95%CI, 0.40-0.43] for eICU-CRD and 0.53 [95%CI, 0.50-0.55] for MIMIC). This association was consistent across subgroup analyses. The optimal range of Spo2 was 94%to 98%and should inform future trials of oxygen therapy.

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...

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.

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...

Effect of fluctuation of oxygenation and time spent in the target range on retinopathy of prematurity in extremely low birth weight infants.

The association between saturation of peripheral oxygenation (SpO2) fluctuation and severity of retinopathy of prematurity (ROP) is well elucidated in extremely low birth weight (ELBW) infants. Time spent in the Target range of SpO2 is also associated with the severity of ROP. In a prospective observational study, the SpO2 of all ELBW infants admitted to our unit were monitored for the first four weeks of life, and averaged every minute for analysis. The percent time spent at SpO2 <90%, 90-95%, and >95% and weekly SpO2 fluctuations [as SpO2 coefficient of variation (CoV)] were calculated. During the study period 21 infants had moderate to severe ROP and 35 infants served as controls. Infants with moderate to severe ROP were smaller and younger than their controls [676±124 grams vs. 796±148 grams (p < 0.001); and 24.0±1.0 weeks vs. 25.0±1.7 weeks (p < 0.001) respectively]. There were no significant differences in time spent in the 90-95% range between groups (p = 0.66). However there was a significant increase in weekly SpO2 CoV in infants with moderate to severe ROP vs. controls (p = 0.007). In ELBW infants, there was an association between SpO2 fluctuation during the first four weeks of life and severity of ROP, although, no association was established with time spent in the target range of SpO2.

A Novel Auditory Display for Neonatal Resuscitation: Laboratory Studies Simulating Pulse Oximetry in the First 10 Minutes After Birth.

We tested whether enhanced sonifications would improve participants' ability to judge the oxygen saturation levels (SpO2) of simulated neonates in the first 10 min after birth. During the resuscitation of a newborn infant, clinicians must keep the neonate's SpO2 levels within the target range, however the boundaries for the target range change each minute during the first 10 min after birth. Resuscitation places significant demand on the clinician's visual attention, and the pulse oximeter's sonification could provide eyes-free monitoring. However, clinicians have difficulty judging SpO2 levels using the current sonification. In two experiments, nonclinicians' ability to detect SpO2 range and direction-while performing continuous arithmetic problems-was tested with enhanced versus conventional sonifications. In Experiment 1, tremolo signaled when SpO2 had deviated below or above the target range. In Experiment 2, tremolo plus brightness signaled when SpO2 was above target range, and tremolo alone when SpO2 was below target range. The tremolo sonification improved range identification accuracy over the conventional display (81% vs. 63%, p < .001). The tremolo plus brightness sonification further improved range identification accuracy over the conventional display (92% vs. 62%, p <.001). In both experiments, there was no difference across conditions in arithmetic task accuracy ( p >.05). Using the enhanced sonifications, participants identified SpO2 range more accurately despite a continuous distractor task. An enhanced pulse oximetry sonification could help clinicians multitask more effectively during neonatal resuscitations.

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.

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.

Excess oxygen in acute illness: adding fuel to the fire

Oxygen is essential for life and is the third most abundant element in the universe. This abundance is evident in the treatment of acutely ill adults admitted to intensive and progressive care units around the world, in whom excess oxygen is frequently provided for inhalation. The typical motivation for liberal oxygen administration is the prevention of hypoxaemia. By contrast, few health-care providers are concerned about hyperoxaemia—ie, highly elevated arterial oxygen concentrations (arterial oxygen tension >100 mm Hg). As a cardiologist working in cardiac intensive care, I am familiar with the panic often incited by a patient with hypoxaemia. Bedside alarms ring, nurses justifiably fret, and pagers vibrate. However, I have never been called to treat a patient with hyperoxaemia. On the basis of accumulating observational evidence 1 Damiani E Adrario E Girardis M et al. Arterial hyperoxia and mortality in critically ill patients: a systematic review and meta-analysis. Crit Care. 2014; 18: 711 Crossref PubMed Scopus (210) Google Scholar , 2 Helmerhorst HJ Roos-Blom MJ van Westerloo DJ de Jonge E Association between arterial hyperoxia and outcome in subsets of critical illness: a systematic review, meta-analysis, and meta-regression of cohort studies. Crit Care Med. 2015; 43: 1508-1519 Crossref PubMed Scopus (198) Google Scholar , 3 Aggarwal NR Brower RG Hager DN et al. Oxygen exposure resulting in arterial oxygen tensions above the protocol goal was associated with worse clinical outcomes in acute respiratory distress syndrome. Crit Care Med. 2018; 46: 517-524 Crossref PubMed Scopus (55) Google Scholar and a compelling meta-analysis of randomised trials by Derek K Chu and colleagues in The Lancet, 4 Chu DK Kim LH-Y Young PJ et al. Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): a systematic review and meta-analysis. Lancet. 2018; 391: 1693-1705 Summary Full Text Full Text PDF PubMed Scopus (411) Google Scholar perhaps that is about to change. Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): a systematic review and meta-analysisIn acutely ill adults, high-quality evidence shows that liberal oxygen therapy increases mortality without improving other patient-important outcomes. Supplemental oxygen might become unfavourable above an SpO2 range of 94–96%. These results support the conservative administration of oxygen therapy. Full-Text PDF

Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): a systematic review and meta-analysis

Supplemental oxygen is often administered liberally to acutely ill adults, but the credibility of the evidence for this practice is unclear. We systematically reviewed the efficacy and safety of liberal versus conservative oxygen therapy in acutely ill adults. In the Improving Oxygen Therapy in Acute-illness (IOTA) systematic review and meta-analysis, we searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, HealthSTAR, LILACS, PapersFirst, and the WHO International Clinical Trials Registry from inception to Oct 25, 2017, for randomised controlled trials comparing liberal and conservative oxygen therapy in acutely ill adults (aged ≥18 years). Studies limited to patients with chronic respiratory diseases or psychiatric disease, patients on extracorporeal life support, or patients treated with hyperbaric oxygen therapy or elective surgery were excluded. We screened studies and extracted summary estimates independently and in duplicate. We also extracted individual patient-level data from survival curves. The main outcomes were mortality (in-hospital, at 30 days, and at longest follow-up) and morbidity (disability at longest follow-up, risk of hospital-acquired pneumonia, any hospital-acquired infection, and length of hospital stay) assessed by random-effects meta-analyses. We assessed quality of evidence using the grading of recommendations assessment, development, and evaluation approach. This study is registered with PROSPERO, number CRD42017065697. 25 randomised controlled trials enrolled 16 037 patients with sepsis, critical illness, stroke, trauma, myocardial infarction, or cardiac arrest, and patients who had emergency surgery. Compared with a conservative oxygen strategy, a liberal oxygen strategy (median baseline saturation of peripheral oxygen [SpO2] across trials, 96% [range 94-99%, IQR 96-98]) increased mortality in-hospital (relative risk [RR] 1·21, 95% CI 1·03-1·43, I2=0%, high quality), at 30 days (RR 1·14, 95% CI 1·01-1·29, I2=0%, high quality), and at longest follow-up (RR 1·10, 95% CI 1·00-1·20, I2=0%, high quality). Morbidity outcomes were similar between groups. Findings were robust to trial sequential, subgroup, and sensitivity analyses. In acutely ill adults, high-quality evidence shows that liberal oxygen therapy increases mortality without improving other patient-important outcomes. Supplemental oxygen might become unfavourable above an SpO2 range of 94-96%. These results support the conservative administration of oxygen therapy. None.

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

To conduct a systematic review of clinical trials comparing automated versus manual fraction of inspired oxygen (FiO2) control to target oxygen saturation (SpO2) in preterm infants. The authors searched MEDLINE, Embase, CENTRAL, and CINAHL from inception upto December 2016, reviewed conference proceedings and sought results of unpublished trials. Studies were included if automated FiO2 control was compared to manual control in preterm infants on positive pressure respiratory support. The primary outcome was percentage of time spent within the target SpO2 range. Summary mean differences (MD) were computed using random effects model. Out of 276 identified studies 10 met the inclusion criteria. Automated FiO2 control significantly improved time being spent within the target SpO2 range [MD: 12.8%; 95% CI: 6.5-19.2%; I2 = 90%]. Periods of hyperoxia (MD:-8.8%; 95% CI: -15 to -2.7%), severe hypoxia(SpO2 < 80%)(MD: -0.9%;95%CI: -1.5 to -0.4%) and hypoxic events (MD: -5.6%; 95% CI: -9.1 to -2.1%) were significantly reduced with automated control. Automated FiO2 adjustment provides significant improvement of time in target saturations, reduces periods of hyperoxia, and severe hypoxia in preterm infants on positive pressure respiratory support.

LEVEL ESTIMATION OF BLOOD SATURATION AT PATIENTS WITH CHRONIC KIDNEY DISEASE ON THE PROGRAM HEMODIALYSIS

Patients with chronic kidney disease, who are on outpatient program of hemodialysis treatment, have a risk of development of intradialysis chronic hypoxemia (hypoxemia, that appears during the hemodialysis), that appears during the program dialysis treatment.&#x0D; Aim: identifying of patients with Chronic kidney disease with decrease of the percentage oxyhemoglobin content in arterial blood during hemodialysis.&#x0D; Materials and Methods. Participated 91 patients with Chronic kidney disease on the program hemodialysis, who were monitored under the non-invasive method of pulsoximetry of blood saturation.&#x0D; Results. During the research was found that the first group of patients with initial normal medical parameters (SpO2 within the normal range 95-99%) consisted 57 patients (62,6% from the general quantity); to the second group (SpO2 within 90-94%) (including,16 patients, medical parameters of whom were changed with time) belonged 21 patients (23,1%); to the third group (SpO2 range less than 90%) belonged 14 patients (15,4%) (13 of whom came to third group from second and one person got into this group with the previously normal medical parameters).&#x0D; Conclusion. Part of the patients on program hemodialysis may occur the blood saturation fluctuation, with exposure of hypoxemia conditions, that may worsen the prognosis and increase the complication of the disease.