Intensivists’response to hyperoxemia in mechanical ventilation patients:The status quo and related factors

BACKGROUND:Due to the still sparse literature in China,the investigation of hyperoxemia management is required.Thus,we aim to conduct a retrospective study to provide more information about hyperoxemia management in intensive care unit(ICU)patients.METHODS:We retrospectively screened the medical records of adult patients(age≥18 years)who required mechanical ventilation(MV)≥24 hours from January 1,2018,to December 31,2018.All arterial blood gas(ABG)tested during MV was retrieved,and MV settings were recorded.The median arterial partial pressure of oxygen(PaO2)>120 mmHg(1 mmHg=0.133 kPa)was defined as mild to moderate hyperoxemia,and PaO2>300 mmHg as extreme hyperoxemia.Intensivists’response to hyperoxemia was assessed based on the reduction of fraction of inspired oxygen(FiO2)within one hour after hyperoxemia was recorded.Multivariable logistic regression analysis was performed to determine the independent factors associated with the intensivists’response to hyperoxemia.RESULTS:A total of 592 patients were fi nally analyzed.The median Acute Physiology and Chronic Health Evaluation II(APACHE II)score was 21(15-26).The PaO2,arterial oxygen saturation(SaO2),FiO2,and positive end expiratory pressure(PEEP)were 96.4(74.0-126.0)mmHg,97.8%(95.2%-99.1%),0.4(0.4-0.5),and 5(3-6)cmH2O,respectively.Totally 174(29.39%)patients had PaO2>120 mmHg,and 19(3.21%)patients had extreme hyperoxemia at PaO2>300 mmHg.In cases of mild to moderate hyperoxemia with FiO2≤0.4,only 13(2.20%)patients had a decrease in FiO2 within one hour.The multivariable logistic regression analysis showed that a positive response was independently associated with FiO2(odds ratio[OR]1.09,95%confi dence interval[CI]1.06-1.12,P<0.001),PaO2(OR 1.01,95%CI 1.00-1.01,P=0.002),and working shifts(OR 5.09,95%CI 1.87-13.80,P=0.001).CONCLUSIONS:Hyperoxemia occurs frequently and is neglected in most cases,particularly when mild to moderate hyperoxemia,hyperoxemia with lower FiO2,hyperoxemia during night and middle-night shifts,or FiO2 less likely to be decreased.Patients may be at a risk of oxygen toxicity because of the liberal oxygen strategy.Therefore,further research is needed to improve oxygen management for patients with MV in the ICUs.

Oxygenation target in acute respiratory distress syndrome

Determining oxygenation targets in acute respiratory distress syndrome(ARDS)remains a challenge.Althoughoxygenation targets have been used since ARDS was first described,they have not been investigated in detail.However,recent retrospective and prospective trials have evaluated the optimal oxygenation threshold in patientsadmitted to the general intensive care unit.In view of the lack of prospective data,clinicians continue to relyon data from the few available trials to identify the optimal oxygenation strategy.Assessment of the cost-benefitratio of the fraction of inspired oxygen(FiO_(2))to the partial pressure of oxygen in the arterial blood(PaO_(2))is an additional challenge.A high FiO_(2) has been found to be responsible for respiratory failure and deaths innumerous animal models.Low and high PaO_(2) values have also been demonstrated to be potential risk factors inexperimental and clinical situations.The findings from this literature review suggest that PaO_(2) values rangingbetween 80 mmHg and 90 mmHg are acceptable in patients with ARDS.The costs of rescue maneuvers needed toreach these targets have been discussed.Several recent papers have highlighted the risk of disagreement betweenarterial oxygen saturation(SaO_(2))and peripheral oxygen saturation(SpO_(2))values.In order to avoid discrepanciesand hidden hypoxemia,SpO_(2) readings need to be compared with those of SaO_(2).Higher SpO_(2) values may beneeded to achieve the recommended PaO_(2) and SaO_(2) values.

Relationship between PaO_(2)/FiO_(2) and delirium in intensive care:A cross-sectional study

Background::To investigate the relationship between partial pressure of oxygen(PaO_(2))/fraction of inspired oxygen(FiO_(2))and the probability of delirium in intensive care units(ICUs).Methods::The investigation was a cross-sectional study that involved the collection of data from patients admitted to the Xiang Ya Hospital Cardiothoracic Surgical Care Unit and Comprehensive Intensive Care Unit from 01 September 2016 to 10 December 2016.Delirium was diagnosed using the simplified version of the Chinese Confusion Assessment Method(CAM)for the ICU.Demographic and medical data were obtained within 24 h of each patient admitted in the ICU.The PaO_(2)/FiO_(2) of each patient was recorded 24 h after admission in the ICU.The patients were divided into three groups according to PaO_(2)/FiO_(2) data:normal(PaO_(2)/FiO_(2)≥300 mmHg),slightly low(200≥PaO_(2)/FiO_(2)<300 mmHg),and severely low(PaO_(2)/FiO_(2)<200 mmHg).Baseline characteristics were compared in the three groups.Results of the unadjusted model,minimally adjusted model,and fully adjusted model are presented.Results::A total of 403 participants were included in the study,of which 184(45.7%)developed delirium.Age(P<0.001),Sequential Organ Failure Assessment(SOFA)score(P<0.001),Acute Physiology and Chronic Health Evaluation(APACHE)II score(P<0.001),mechanical ventilation time(P<0.001),history of hypertension(P=0.040),heart disease(P=0.040),sedation(P=0.001),and PaO_(2)/FiO_(2)(P=0.006)were significantly associated with delirium in univariate analysis.Multivariate regression analysis models were used to further analyze the associations between PaO_(2)/FiO_(2) and delirium.In the crude model,for 1 standard deviation(SD)increase in PaO_(2)/FiO_(2),the odds ratio(OR)of delirium was 0.8(95%confidence interval[CI]:0.6-0.9),but there was no significant correlation in the fully adjusted model.There was a non-linear relationship between the PaO_(2)/FiO_(2) and delirium in a generalized additive model.A two-piecewise linear regression model was used to calculate a PaO_(2)/FiO_(2) threshold of 243 mmHg.On the left side of the threshold,the OR was 0.9 and the 95%CI was 0.9-1.0(P=0.013)when PaO_(2)/FiO_(2) increased by 1 SD.Conclusions::PaO_(2)/FiO_(2) was negatively associated with delirium when PaO_(2)/FiO_(2) was below the identified threshold.As a readily available laboratory indicator,PaO_(2)/FiO_(2) has potential value in the clinical evaluation of risk of delirium in ICU patients.

Clinical Parameters in the First 5 Minutes after Birth Have a Predictive Value for Survival of Extremely Preterm Infants

Extreme preterm infants(<28 weeks'gestation)often require positive pressure ventilation with oxygen during postnatal stabilization in the delivery room.To date,optimal inspired fraction of oxygen(FiO_(2))still represents a conundrum in newborn care oscillating between higher(>60%)and lower(<30%)initial FiO_(2).Recent evidence and meta-analyses have underscored the predictive value for survival and/or relevant clinical outcomes of the Apgar score and the achievement of arterial oxygen saturation measured by pulse oximetry≥85%at 5 minutes after birth.New clinical trials comparing higher versus lower initial FiO_(2)have been launched aiming to optimize postnatal stabilization of extreme preterm while avoiding adverse effects of hypoxemia or hyperoxemia.