Use of excessive supplemental oxygen in mechanically ventilated patients is based on unit culture. A multiple-methods study in a regional intensive care unit

A dimensional analysis of nursing unit culture

AIM(S)

Organizational culture has been studied for over four decades among nurses, across countries and contexts. However, wide variation exists in how the concept has been defined and at what level of the organization it is measured. The aim of this study was to use a dimensional analysis to conduct a conceptual synthesis of unit culture from a nursing perspective.

DESIGN

Dimensional analysis, rooted in grounded theory methodology, was used to describe unit culture from a nursing perspective.

METHODS

A literature search was conducted in April 2022. Inclusion criteria were (1) peer review publications, (2) used the term 'unit culture' or 'ward culture', (3) references nurses' role in unit culture, (4) published in the last 20 years and (5) written in English. One hundred fifteen articles met inclusion criteria, but dimensional saturation was researched after coding 24 articles.

RESULTS

Findings were synthesized into four core dimensions and 10 subdimensions. Dimensions of unit culture included customs (practice norms, communication and prioritization), shared beliefs (assumptions, values and attitudes), hierarchy (social and informational) and atmosphere (emotional climate and collaboration). Conditions that shape unit culture include individual nurse characteristics, working conditions, unit policies/procedures and leadership. Unit culture impacts nurse work experiences and decision-making processes, which can affect outcomes including nurse wellbeing, practice behaviours and adherence to unit policies.

CONCLUSIONS

Identifying the dimensions of unit culture helps to bring clarity to a concept that is not well defined in existing literature.

IMPACT

This model of unit culture can be used to guide development of new instruments to measure unit culture or guide researchers in utilizing existing measures. Developing measures specific to unit culture are warranted to strengthen researchers' ability to assess how changing conditions of a unit (e.g. leadership, workload) changes unit culture and its related outcomes.

PATIENT OR PUBLIC CONTRIBUTION

No Patient or Public Contribution.

The Effect of Hyperoxemia on Neurological Outcomes of Adult Patients: A Systematic Review and Meta-Analysis

Hyperoxemia commonly occurs in clinical practice and is often left untreated. Many studies have shown increased mortality in patients with hyperoxemia, but data on neurological outcome in these patients are conflicting, despite worsened neurological outcome found in preclinical studies. To investigate the association between hyperoxemia and neurological outcome in adult patients, we performed a systematic review and meta-analysis of observational studies. We searched MEDLINE, Embase, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and ClinicalTrials.gov from inception to May 2020 for observational studies correlating arterial oxygen partial pressure (PaO₂) with neurological status in adults hospitalized with acute conditions. Studies of chronic pulmonary disease or hyperbaric oxygenation were excluded. Relative risks (RRs) were pooled at the study level by using a random-effects model to compare the risk of poor neurological outcome in patients with hyperoxemia and patients without hyperoxemia. Sensitivity and subgroup analyses and assessments of publication bias and risk of bias were performed. Maximum and mean PaO₂ in patients with favorable and unfavorable outcomes were compared using standardized mean difference (SMD). Of 6255 records screened, 32 studies were analyzed. Overall, hyperoxemia was significantly associated with an increased risk of poor neurological outcome (RR 1.13, 95% confidence interval [CI] 1.05-1.23, statistical heterogeneity I² 58.8%, 22 studies). The results were robust across sensitivity analyses. Patients with unfavorable outcome also showed a significantly higher maximum PaO₂ (SMD 0.17, 95% CI 0.04-0.30, I² 78.4%, 15 studies) and mean PaO₂ (SMD 0.25, 95% CI 0.04-0.45, I² 91.0%, 13 studies). These associations were pronounced in patients with subarachnoid hemorrhage (RR 1.34, 95% CI 1.14-1.56) and ischemic stroke (RR 1.41, 95% CI 1.14-1.74), but not in patients with cardiac arrest, traumatic brain injury, or following cardiopulmonary bypass. Hyperoxemia is associated with poor neurological outcome, especially in patients with subarachnoid hemorrhage and ischemic stroke. Although our study cannot establish causality, PaO₂ should be monitored closely because hyperoxemia may be associated with worsened patient outcome and consequently affect the patient's quality of life.

Arterial oxygen pressure targets in critically ill patients: Analysis of a large ICU database

BACKGROUND

Providing supplemental oxygen is common in the management of critically ill patients, yet the optimal oxygen regimen remains unclear.

OBJECTIVES

To explore the optimal range of PaO₂ in critically ill patients.

METHODS

This is a retrospective study conducted in the Medical Information Mart for Intensive Care III (MIMIC-III) database. The patients with a least 48 h of oxygen therapy were included. Nonlinear regression was used to analyze the association between PaO₂ and mortality. We derived an optimal range of PaO₂ and evaluated the association between the proportion of PaO₂ measurements within this range and mortality.

RESULTS

In total, 8401 patients were included in the study. A J-shaped relationship was observed between median PaO₂ and hospital mortality. Compared with the reference group of 100-120 mmHg, patients with values of 80-100 mmHg and 120-140 mmHg had higher hospital mortality (adjusted odds ratio [aOR], 1.23; 95% CI, 1.05-1.43 and 1.29; 95%CI, 1.08-1.54, respectively). Similarly, mortality rates were significantly higher for PaO₂ <80 mmHg and ≥140 mmHg (aOR, 1.97; 95%CI, 1.58-2.45 and 1.42; 95%CI, 1.19-1.69, respectively). Patients spent a greater proportion of time within 100-120 mmHg tended to have a lower mortality rate.

CONCLUSION

Among critically ill patients, the relationship between median PaO₂ and hospital mortality was J-shaped. The lowest rates of mortality was observed in those with PaO₂ levels within 100 to 120 mmHg.