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.