Purpose
Intubation in patients with respiratory failure can be avoided by high-flow nasal cannula (HFNC) use. However, it is unclear whether waiting until HFNC fails, which would delay intubation, ...has adverse effects. The present retrospective observational study assessed overall ICU mortality and other hospital outcomes of patients who received HFNC therapy that failed.
Methods
All consecutive patients in one tertiary hospital who received HFNC therapy that failed and who then required intubation between January 2013 and March 2014 were enrolled and classified according to whether intubation started early (within 48 h) or late (at least 48 h) after commencing HFNC.
Results
Of the 175 enrolled patients, 130 (74.3 %) and 45 (25.7 %) were intubated before and after 48 h of HFNC, respectively. The groups were similar in terms of most baseline characteristics. The early intubated patients had better overall ICU mortality (39.2 vs. 66.7 %;
P
= 0.001) than late intubated patients. A similar pattern was seen with extubation success (37.7 vs. 15.6 %;
P
= 0.006), ventilator weaning (55.4 vs. 28.9 %;
P
= 0.002), and ventilator-free days (8.6 ± 10.1 vs. 3.6 ± 7.5;
P
= 0.011). In propensity-adjusted and -matched analysis, early intubation was also associated with better overall ICU mortality adjusted odds ratio (OR) = 0.317,
P
= 0.005; matched OR = 0.369,
P
= 0.046.
Conclusions
Failure of HFNC might cause delayed intubation and worse clinical outcomes in patients with respiratory failure. Large prospective and randomized controlled studies on HFNC failure are needed to draw a definitive conclusion.
Purpose
Nasal continuous positive airway pressure (nCPAP) is currently the gold standard for respiratory support for moderate to severe acute viral bronchiolitis (AVB). Although oxygen delivery via ...high flow nasal cannula (HFNC) is increasingly used, evidence of its efficacy and safety is lacking in infants.
Methods
A randomized controlled trial was performed in five pediatric intensive care units (PICUs) to compare 7 cmH
2
O nCPAP with 2 L/kg/min oxygen therapy administered with HFNC in infants up to 6 months old with moderate to severe AVB. The primary endpoint was the percentage of failure within 24 h of randomization using prespecified criteria. To satisfy noninferiority, the failure rate of HFNC had to lie within 15% of the failure rate of nCPAP. Secondary outcomes included success rate after crossover, intubation rate, length of stay, and serious adverse events.
Results
From November 2014 to March 2015, 142 infants were included and equally distributed into groups. The risk difference of −19% (95% CI −35 to −3%) did not allow the conclusion of HFNC noninferiority (
p
= 0.707). Superiority analysis suggested a relative risk of success 1.63 (95% CI 1.02–2.63) higher with nCPAP. The success rate with the alternative respiratory support, intubation rate, durations of noninvasive and invasive ventilation, skin lesions, and length of PICU stay were comparable between groups. No patient had air leak syndrome or died.
Conclusion
In young infants with moderate to severe AVB, initial management with HFNC did not have a failure rate similar to that of nCPAP. This clinical trial was recorded in the National Library of Medicine registry (NCT 02457013).
It has not been established whether noninvasive ventilation (NIV) reduces the need for invasive mechanical ventilation in patients who develop hypoxemic acute respiratory failure after abdominal ...surgery.
To evaluate whether noninvasive ventilation improves outcomes among patients developing hypoxemic acute respiratory failure after abdominal surgery.
Multicenter, randomized, parallel-group clinical trial conducted between May 2013 and September 2014 in 20 French intensive care units among 293 patients who had undergone abdominal surgery and developed hypoxemic respiratory failure (partial oxygen pressure <60 mm Hg or oxygen saturation SpO2 ≤90% when breathing room air or <80 mm Hg when breathing 15 L/min of oxygen, plus either 1 a respiratory rate above 30/min or 2 clinical signs suggestive of intense respiratory muscle work and/or labored breathing) if it occurred within 7 days after surgical procedure.
Patients were randomly assigned to receive standard oxygen therapy (up to 15 L/min to maintain SpO2 of 94% or higher) (n = 145) or NIV delivered via facial mask (inspiratory pressure support level, 5-15 cm H2O; positive end-expiratory pressure, 5-10 cm H2O; fraction of inspired oxygen titrated to maintain SpO2 ≥94%) (n = 148).
The primary outcome was tracheal reintubation for any cause within 7 days of randomization. Secondary outcomes were gas exchange, invasive ventilation-free days at day 30, health care-associated infections, and 90-day mortality.
Among the 293 patients (mean age, 63.4 SD, 13.8 years; n=224 men) included in the intention-to-treat analysis, reintubation occurred in 49 of 148 (33.1%) in the NIV group and in 66 of 145 (45.5%) in the standard oxygen therapy group within+ 7 days after randomization (absolute difference, -12.4%; 95% CI, -23.5% to -1.3%; P = .03). Noninvasive ventilation was associated with significantly more invasive ventilation-free days compared with standard oxygen therapy (25.4 vs 23.2 days; absolute difference, -2.2 days; 95% CI, -0.1 to 4.6 days; P = .04), while fewer patients developed health care-associated infections (43/137 31.4% vs 63/128 49.2%; absolute difference, -17.8%; 95% CI, -30.2% to -5.4%; P = .003). At 90 days, 22 of 148 patients (14.9%) in the NIV group and 31 of 144 (21.5%) in the standard oxygen therapy group had died (absolute difference, -6.5%; 95% CI, -16.0% to 3.0%; P = .15). There were no significant differences in gas exchange.
Among patients with hypoxemic respiratory failure following abdominal surgery, use of NIV compared with standard oxygen therapy reduced the risk of tracheal reintubation within 7 days. These findings support use of NIV in this setting.
clinicaltrials.gov Identifier: NCT01971892.
Background
This systematic review and meta-analysis summarizes the safety and efficacy of high flow nasal cannula (HFNC) in patients with acute hypoxemic respiratory failure.
Methods
We performed a ...comprehensive search of MEDLINE, EMBASE, and Web of Science. We identified randomized controlled trials that compared HFNC to conventional oxygen therapy. We pooled data and report summary estimates of effect using relative risk for dichotomous outcomes and mean difference or standardized mean difference for continuous outcomes, with 95% confidence intervals. We assessed risk of bias of included studies using the Cochrane tool and certainty in pooled effect estimates using GRADE methods.
Results
We included 9 RCTs (
n
= 2093 patients). We found no difference in mortality in patients treated with HFNC (relative risk RR 0.94, 95% confidence interval CI 0.67–1.31, moderate certainty) compared to conventional oxygen therapy. We found a decreased risk of requiring intubation (RR 0.85, 95% CI 0.74–0.99) or escalation of oxygen therapy (defined as crossover to HFNC in the control group, or initiation of non-invasive ventilation or invasive mechanical ventilation in either group) favouring HFNC-treated patients (RR 0.71, 95% CI 0.51–0.98), although certainty in both outcomes was low due to imprecision and issues related to risk of bias. HFNC had no effect on intensive care unit length of stay (mean difference MD 1.38 days more, 95% CI 0.90 days fewer to 3.66 days more, low certainty), hospital length of stay (MD 0.85 days fewer, 95% CI 2.07 days fewer to 0.37 days more, moderate certainty), patient reported comfort (SMD 0.12 lower, 95% CI 0.61 lower to 0.37 higher, very low certainty) or patient reported dyspnea (standardized mean difference SMD 0.16 lower, 95% CI 1.10 lower to 1.42 higher, low certainty). Complications of treatment were variably reported amongst included studies, but little harm was associated with HFNC use.
Conclusion
In patients with acute hypoxemic respiratory failure, HFNC may decrease the need for tracheal intubation without impacting mortality.
High-flow conditioned oxygen therapy delivered through nasal cannulae and noninvasive mechanical ventilation (NIV) may reduce the need for reintubation. Among the advantages of high-flow oxygen ...therapy are comfort, availability, lower costs, and additional physiopathological mechanisms.
To test if high-flow conditioned oxygen therapy is noninferior to NIV for preventing postextubation respiratory failure and reintubation in patients at high risk of reintubation.
Multicenter randomized clinical trial in 3 intensive care units in Spain (September 2012-October 2014) including critically ill patients ready for planned extubation with at least 1 of the following high-risk factors for reintubation: older than 65 years; Acute Physiology and Chronic Health Evaluation II score higher than 12 points on extubation day; body mass index higher than 30; inadequate secretions management; difficult or prolonged weaning; more than 1 comorbidity; heart failure as primary indication for mechanical ventilation; moderate to severe chronic obstructive pulmonary disease; airway patency problems; or prolonged mechanical ventilation.
Patients were randomized to undergo either high-flow conditioned oxygen therapy or NIV for 24 hours after extubation.
Primary outcomes were reintubation and postextubation respiratory failure within 72 hours. Noninferiority margin was 10 percentage points. Secondary outcomes included respiratory infection, sepsis, and multiple organ failure, length of stay and mortality; adverse events; and time to reintubation.
Of 604 patients (mean age, 65 SD, 16 years; 388 64% men), 314 received NIV and 290 high-flow oxygen. Sixty-six patients (22.8%) in the high-flow group vs 60 (19.1%) in the NIV group were reintubation (absolute difference, -3.7%; 95% CI, -9.1% to ∞); 78 patients (26.9%) in the high-flow group vs 125 (39.8%) in the NIV group experienced postextubation respiratory failure (risk difference, 12.9%; 95% CI, 6.6% to ∞) corrected. Median time to reintubation did not significantly differ: 26.5 hours (IQR, 14-39 hours) in the high-flow group vs 21.5 hours (IQR, 10-47 hours) in the NIV group (absolute difference, -5 hours; 95% CI, -34 to 24 hours). Median postrandomization ICU length of stay was lower in the high-flow group, 3 days (IQR, 2-7) vs 4 days (IQR, 2-9; P=.048). Other secondary outcomes were similar in the 2 groups. Adverse effects requiring withdrawal of the therapy were observed in none of patients in the high-flow group vs 42.9% patients in the NIV group (P < .001).
Among high-risk adults who have undergone extubation, high-flow conditioned oxygen therapy was not inferior to NIV for preventing reintubation and postextubation respiratory failure. High-flow conditioned oxygen therapy may offer advantages for these patients.
clinicaltrials.gov Identifier: NCT01191489.
Background
Available evidence on the effects of a high fraction of inspired oxygen (FIO2) of 60% to 90% compared with a routine fraction of inspired oxygen of 30% to 40%, during anaesthesia and ...surgery, on mortality and surgical site infection has been inconclusive. Previous trials and meta‐analyses have led to different conclusions on whether a high fraction of supplemental inspired oxygen during anaesthesia may decrease or increase mortality and surgical site infections in surgical patients.
Objectives
To assess the benefits and harms of an FIO2 equal to or greater than 60% compared with a control FIO2 at or below 40% in the perioperative setting in terms of mortality, surgical site infection, respiratory insufficiency, serious adverse events and length of stay during the index admission for adult surgical patients.
We looked at various outcomes, conducted subgroup and sensitivity analyses, examined the role of bias and applied trial sequential analysis (TSA) to examine the level of evidence supporting or refuting a high FIO2 during surgery, anaesthesia and recovery.
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, BIOSIS, International Web of Science, the Latin American and Caribbean Health Science Information Database (LILACS), advanced Google and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) up to February 2014. We checked the references of included trials and reviews for unidentified relevant trials and reran the searches in March 2015. We will consider two studies of interest when we update the review.
Selection criteria
We included randomized clinical trials that compared a high fraction of inspired oxygen with a routine fraction of inspired oxygen during anaesthesia, surgery and recovery in individuals 18 years of age or older.
Data collection and analysis
Two review authors extracted data independently. We conducted random‐effects and fixed‐effect meta‐analyses, and for dichotomous outcomes, we calculated risk ratios (RRs). We used published data and data obtained by contacting trial authors.
To minimize the risk of systematic error, we assessed the risk of bias of the included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta‐analyses, we applied trial sequential analyses. We used Grades of Recommendation, Assessment, Development and Evaluation (GRADE) to assess the quality of the evidence.
Main results
We included 28 randomized clinical trials (9330 participants); in the 21 trials reporting relevant outcomes for this review, 7597 participants were randomly assigned to a high fraction of inspired oxygen versus a routine fraction of inspired oxygen.
In trials with an overall low risk of bias, a high fraction of inspired oxygen compared with a routine fraction of inspired oxygen was not associated with all‐cause mortality (random‐effects model: RR 1.12, 95% confidence interval (CI) 0.93 to 1.36; GRADE: low quality) within the longest follow‐up and within 30 days of follow‐up (Peto odds ratio (OR) 0.99, 95% CI 0.61 to 1.60; GRADE: low quality). In a trial sequential analysis, the required information size was not reached and the analysis could not refute a 20% increase in mortality. Similarly, when all trials were included, a high fraction of inspired oxygen was not associated with all‐cause mortality to the longest follow‐up (RR 1.07, 95% CI 0.87 to 1.33) or within 30 days of follow‐up (Peto OR 0.83, 95% CI 0.54 to 1.29), both of very low quality according to GRADE. Neither was a high fraction of inspired oxygen associated with the risk of surgical site infection in trials with low risk of bias (RR 0.86, 95% CI 0.63 to 1.17; GRADE: low quality) or in all trials (RR 0.87, 95% CI 0.71 to 1.07; GRADE: low quality). A high fraction of inspired oxygen was not associated with respiratory insufficiency (RR 1.25, 95% CI 0.79 to 1.99), serious adverse events (RR 0.96, 95% CI 0.65 to 1.43) or length of stay (mean difference ‐0.06 days, 95% CI ‐0.44 to 0.32 days).
In subgroup analyses of nine trials using preoperative antibiotics, a high fraction of inspired oxygen was associated with a decrease in surgical site infections (RR 0.76, 95% CI 0.60 to 0.97; GRADE: very low quality); a similar effect was noted in the five trials adequately blinded for the outcome assessment (RR 0.79, 95% CI 0.66 to 0.96; GRADE: very low quality). We did not observe an effect of a high fraction of inspired oxygen on surgical site infections in any other subgroup analyses.
Authors' conclusions
As the risk of adverse events, including mortality, may be increased by a fraction of inspired oxygen of 60% or higher, and as robust evidence is lacking for a beneficial effect of a fraction of inspired oxygen of 60% or higher on surgical site infection, our overall results suggest that evidence is insufficient to support the routine use of a high fraction of inspired oxygen during anaesthesia and surgery. Given the risk of attrition and outcome reporting bias, as well as other weaknesses in the available evidence, further randomized clinical trials with low risk of bias in all bias domains, including a large sample size and long‐term follow‐up, are warranted.
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.
Background
High‐flow nasal cannulae (HFNC) deliver high flows of blended humidified air and oxygen via wide‐bore nasal cannulae and may be useful in providing respiratory support for adults ...experiencing acute respiratory failure, or at risk of acute respiratory failure, in the intensive care unit (ICU). This is an update of an earlier version of the review.
Objectives
To assess the effectiveness of HFNC compared to standard oxygen therapy, or non‐invasive ventilation (NIV) or non‐invasive positive pressure ventilation (NIPPV), for respiratory support in adults in the ICU.
Search methods
We searched CENTRAL, MEDLINE, Embase, CINAHL, Web of Science, and the Cochrane COVID‐19 Register (17 April 2020), clinical trial registers (6 April 2020) and conducted forward and backward citation searches.
Selection criteria
We included randomized controlled studies (RCTs) with a parallel‐group or cross‐over design comparing HFNC use versus other types of non‐invasive respiratory support (standard oxygen therapy via nasal cannulae or mask; or NIV or NIPPV which included continuous positive airway pressure and bilevel positive airway pressure) in adults admitted to the ICU.
Data collection and analysis
We used standard methodological procedures as expected by Cochrane.
Main results
We included 31 studies (22 parallel‐group and nine cross‐over designs) with 5136 participants; this update included 20 new studies. Twenty‐one studies compared HFNC with standard oxygen therapy, and 13 compared HFNC with NIV or NIPPV; three studies included both comparisons. We found 51 ongoing studies (estimated 12,807 participants), and 19 studies awaiting classification for which we could not ascertain study eligibility information.
In 18 studies, treatment was initiated after extubation. In the remaining studies, participants were not previously mechanically ventilated.
HFNC versus standard oxygen therapy
HFNC may lead to less treatment failure as indicated by escalation to alternative types of oxygen therapy (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.45 to 0.86; 15 studies, 3044 participants; low‐certainty evidence). HFNC probably makes little or no difference in mortality when compared with standard oxygen therapy (RR 0.96, 95% CI 0.82 to 1.11; 11 studies, 2673 participants; moderate‐certainty evidence). HFNC probably results in little or no difference to cases of pneumonia (RR 0.72, 95% CI 0.48 to 1.09; 4 studies, 1057 participants; moderate‐certainty evidence), and we were uncertain of its effect on nasal mucosa or skin trauma (RR 3.66, 95% CI 0.43 to 31.48; 2 studies, 617 participants; very low‐certainty evidence). We found low‐certainty evidence that HFNC may make little or no difference to the length of ICU stay according to the type of respiratory support used (MD 0.12 days, 95% CI ‐0.03 to 0.27; 7 studies, 1014 participants). We are uncertain whether HFNC made any difference to the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) within 24 hours of treatment (MD 10.34 mmHg, 95% CI ‐17.31 to 38; 5 studies, 600 participants; very low‐certainty evidence). We are uncertain whether HFNC made any difference to short‐term comfort (MD 0.31, 95% CI ‐0.60 to 1.22; 4 studies, 662 participants, very low‐certainty evidence), or to long‐term comfort (MD 0.59, 95% CI ‐2.29 to 3.47; 2 studies, 445 participants, very low‐certainty evidence).
HFNC versus NIV or NIPPV
We found no evidence of a difference between groups in treatment failure when HFNC were used post‐extubation or without prior use of mechanical ventilation (RR 0.98, 95% CI 0.78 to 1.22; 5 studies, 1758 participants; low‐certainty evidence), or in‐hospital mortality (RR 0.92, 95% CI 0.64 to 1.31; 5 studies, 1758 participants; low‐certainty evidence). We are very uncertain about the effect of using HFNC on incidence of pneumonia (RR 0.51, 95% CI 0.17 to 1.52; 3 studies, 1750 participants; very low‐certainty evidence), and HFNC may result in little or no difference to barotrauma (RR 1.15, 95% CI 0.42 to 3.14; 1 study, 830 participants; low‐certainty evidence). HFNC may make little or no difference to the length of ICU stay (MD ‐0.72 days, 95% CI ‐2.85 to 1.42; 2 studies, 246 participants; low‐certainty evidence). The ratio of PaO2/FiO2 may be lower up to 24 hours with HFNC use (MD ‐58.10 mmHg, 95% CI ‐71.68 to ‐44.51; 3 studies, 1086 participants; low‐certainty evidence). We are uncertain whether HFNC improved short‐term comfort when measured using comfort scores (MD 1.33, 95% CI 0.74 to 1.92; 2 studies, 258 participants) and responses to questionnaires (RR 1.30, 95% CI 1.10 to 1.53; 1 study, 168 participants); evidence for short‐term comfort was very low certainty. No studies reported on nasal mucosa or skin trauma.
Authors' conclusions
HFNC may lead to less treatment failure when compared to standard oxygen therapy, but probably makes little or no difference to treatment failure when compared to NIV or NIPPV. For most other review outcomes, we found no evidence of a difference in effect. However, the evidence was often of low or very low certainty. We found a large number of ongoing studies; including these in future updates could increase the certainty or may alter the direction of these effects.
Oxygen is commonly administered after extubation. Although several devices are available, data about their clinical efficacy are scarce.
To compare the effects of the Venturi mask and the nasal ...high-flow (NHF) therapy on PaO2/FiO2SET ratio after extubation. Secondary endpoints were to assess effects on patient discomfort, adverse events, and clinical outcomes.
Randomized, controlled, open-label trial on 105 patients with a PaO2/FiO2 ratio less than or equal to 300 immediately before extubation. The Venturi mask (n = 52) or NHF (n = 53) were applied for 48 hours postextubation.
PaO2/FiO2SET, patient discomfort caused by the interface and by symptoms of airways dryness (on a 10-point numerical rating scale), interface displacements, oxygen desaturations, need for ventilator support, and reintubation were assessed up to 48 hours after extubation. From the 24th hour, PaO2/FiO2SET was higher with the NHF (287 ± 74 vs. 247 ± 81 at 24 h; P = 0.03). Discomfort related both to the interface and to airways dryness was better with NHF (respectively, 2.6 ± 2.2 vs. 5.1 ± 3.3 at 24 h, P = 0.006; 2.2 ± 1.8 vs. 3.7 ± 2.4 at 24 h, P = 0.002). Fewer patients had interface displacements (32% vs. 56%; P = 0.01), oxygen desaturations (40% vs. 75%; P < 0.001), required reintubation (4% vs. 21%; P = 0.01), or any form of ventilator support (7% vs. 35%; P < 0.001) in the NHF group.
Compared with the Venturi mask, NHF results in better oxygenation for the same set FiO2 after extubation. Use of NHF is associated with better comfort, fewer desaturations and interface displacements, and a lower reintubation rate. Clinical trial registered with www.clinicaltrials.gov (NCT 01575353).
There is conflicting evidence on harm related to exposure to supraphysiologic Pa
(hyperoxemia) in critically ill patients.
To examine the association between longitudinal exposure to hyperoxemia and ...mortality in patients admitted to ICUs in five United Kingdom university hospitals.
A retrospective cohort of ICU admissions between January 31, 2014, and December 31, 2018, from the National Institute of Health Research Critical Care Health Informatics Collaborative was studied. Multivariable logistic regression modeled death in ICU by exposure to hyperoxemia.
Subsets with oxygen exposure windows of 0 to 1, 0 to 3, 0 to 5, and 0 to 7 days were evaluated, capturing 19,515, 10,525, 6,360, and 4,296 patients, respectively. Hyperoxemia dose was defined as the area between the Pa
time curve and a boundary of 13.3 kPa (100 mm Hg) divided by the hours of potential exposure (24, 72, 120, or 168 h). An association was found between exposure to hyperoxemia and ICU mortality for exposure windows of 0 to 1 days (odds ratio OR, 1.15; 95% compatibility interval CI, 0.95-1.38;
= 0.15), 0 to 3 days (OR 1.35; 95% CI, 1.04-1.74;
= 0.02), 0 to 5 days (OR, 1.5; 95% CI, 1.07-2.13;
= 0.02), and 0 to 7 days (OR, 1.74; 95% CI, 1.11-2.72;
= 0.02). However, a dose-response relationship was not observed. There was no evidence to support a differential effect between hyperoxemia and either a respiratory diagnosis or mechanical ventilation.
An association between hyperoxemia and mortality was observed in our large, unselected multicenter cohort. The absence of a dose-response relationship weakens causal interpretation. Further experimental research is warranted to elucidate this important question.
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