Contributions to the epidemiology of acute respiratory failure

Implementing High-Flow Nasal Oxygen Therapy in Medical Wards: A Scoping Review to Understand Hospital Protocols and Procedures

Acute hypoxemic respiratory failure (ARF) is a common cause for hospital admission. High-flow nasal oxygen (HFNO) is increasingly used as a first-line treatment for patients with ARF, including in medical wards. Clinical guidance is crucial when providing HFNO, and health services use local health guidance documents (LHGDs) to achieve this. It is unknown what hospital LHGDs recommend regarding ward administration of HFNO. This study examined Australian hospitals' LHGDs regarding ward-based HFNO administration to determine content that may affect safe delivery. A scoping review was undertaken on 2 May 2022 and updated on 29 January 2024 to identify public hospitals' LHGDs regarding delivery of HFNO to adults with ARF in medical wards in two Australian states. Data were extracted and analysed regarding HFNO initiation, monitoring, maintenance and weaning, and management of clinical deterioration. Of the twenty-six included LHGDs, five documents referenced Australian Oxygen Guidelines. Twenty LHGDs did not define a threshold level of hypoxaemia where HFNO use was recommended over conventional oxygen therapy. Thirteen did not provide target oxygen saturation ranges whilst utilising HFNO. Recommendations varied regarding maximal levels of inspired oxygen and flow rates in the medical ward. Eight LHGDs did not specify any system to identify and manage deteriorating patients. Five LHGDs did not provide guidance for weaning patients from HFNO. There was substantial variation in the LHGDs regarding HFNO care for adult patients with ARF in Australian hospitals. These findings have implications for the delivery of high-quality, safe clinical care in hospitals.

The Association Between Endotracheal Tube Size and Aspiration (During Flexible Endoscopic Evaluation of Swallowing) in Acute Respiratory Failure Survivors

OBJECTIVES

To determine whether a modifiable risk factor, endotracheal tube size, is associated with the diagnosis of postextubation aspiration in survivors of acute respiratory failure.

DESIGN

Prospective cohort study.

SETTING

ICUs at four academic tertiary care medical centers.

PATIENTS

Two hundred ten patients who were at least 18 years old, admitted to an ICU, and mechanically ventilated with an endotracheal tube for longer than 48 hours were enrolled.

INTERVENTIONS

Within 72 hours of extubation, all patients received a flexible endoscopic evaluation of swallowing examination that entailed administration of ice, thin liquid, thick liquid, puree, and cracker boluses. Patient demographics, treatment variables, and hospital outcomes were abstracted from the patient's medical records. Endotracheal tube size was independently selected by the patient's treating physicians.

MEASUREMENTS AND MAIN RESULTS

For each flexible endoscopic evaluation of swallowing examination, laryngeal pathology was evaluated, and for each bolus, a Penetration Aspiration Scale score was assigned. Aspiration (Penetration Aspiration Scale score ≥ 6) was further categorized into nonsilent aspiration (Penetration Aspiration Scale score = 6 or 7) and silent aspiration (Penetration Aspiration Scale score = 8). One third of patients (n = 68) aspirated (Penetration Aspiration Scale score ≥ 6) on at least one bolus, 13.6% (n = 29) exhibited silent aspiration, and 23.8% (n = 50) exhibited nonsilent aspiration. In a multivariable analysis, endotracheal tube size (≤ 7.5 vs ≥ 8.0) was significantly associated with patients exhibiting any aspiration (Penetration Aspiration Scale score ≥ 6) (p = 0.016; odds ratio = 2.17; 95% CI 1.14-4.13) and with risk of developing laryngeal granulation tissue (p = 0.02).

CONCLUSIONS

Larger endotracheal tube size was associated with increased risk of aspiration and laryngeal granulation tissue. Using smaller endotracheal tubes may reduce the risk of postextubation aspiration.

The burden of influenza-associated critical illness hospitalizations

OBJECTIVE

Influenza is the most common vaccine-preventable disease in the United States; however, little is known about the burden of critical illness due to influenza virus infection. Our primary objective was to estimate the proportion of all critical illness hospitalizations that are attributable to seasonal influenza.

DESIGN

Retrospective cohort study.

SETTING

Arizona, California, and Washington from January 2003 to March 2009.

PATIENTS

All adults hospitalized with critical illness, defined by International Classification of Diseases, 9th Edition, Clinical Modification diagnosis and procedure codes for acute respiratory failure, severe sepsis, or in-hospital death.

MEASUREMENTS AND MAIN RESULTS

We combined the complete hospitalization discharge databases for three U.S. states, regional influenza virus surveillance, and state census data. Using negative binomial regression models, we estimated the incidence rates of adult influenza-associated critical illness hospitalizations and compared them with all-cause event rates. We also compared modeled outcomes to International Classification of Diseases, 9th Edition, Clinical Modification-coded influenza hospitalizations to assess potential underrecognition of severe influenza disease. During the study period, we estimated that 26,760 influenza-associated critical illness hospitalizations (95% CI, 14,541, 47,464) occurred. The population-based incidence estimate for influenza-associated critical illness was 12.0 per 100,000 person-years (95% CI, 6.6, 21.6) or 1.3% of all critical illness hospitalizations (95% CI, 0.7%, 2.3%). During the influenza season, 3.4% of all critical illness hospitalizations (95% CI, 1.9%, 5.8%) were attributable to influenza. There were only 2,612 critical illness hospitalizations with International Classification of Diseases, 9th Edition, Clinical Modification-coded influenza diagnoses, suggesting influenza is either undiagnosed or undercoded in a substantial proportion of critical illness.

CONCLUSIONS

Extrapolating our data to the 2010 U.S. population, we estimate that about 28,000 adults are hospitalized for influenza-associated critical illness annually. Influenza in many of these critically ill patients may be undiagnosed. Critical care physicians should have a high index of suspicion for influenza in the ICU, particularly when influenza is known to be circulating in their communities.

Nontuberculous mycobacterial infection is associated with increased respiratory failure: a nationwide cohort study

BACKGROUND AND PURPOSE

Population study on relationship between nontuberculous mycobacterial (NTM) infection and respiratory failure (RF) is limited. This study evaluated the RF risk, including acute respiratory failure (ARF), chronic respiratory failure (CRF) and ARF on CRF, in patients with NTM infection in Taiwan.

METHODS

We used the National Health Insurance Research Database of Taiwan to identify 3864 newly diagnosed NTM patients (NTM cohort) from 1999 to 2009, and 15456 non-NTM patients (non-NTM cohort), frequency matched by demographic status for comparison. Incidence and hazard of developing RF were measured by the end of 2010.

RESULTS

The incidence rate of RF was 4.31-fold higher in the NTM cohort than in the non-NTM cohort (44.0 vs.10.2 per 1000 person-years), with an adjusted hazard ratio (HR) of 3.11 (95% CI: 2.73-3.54). The cumulative proportional incidence of RF was 10% higher in the NTM cohort than in the non-NTM cohort (P<0.0001). The RF risk was much greater within 6 months after the diagnosis of NTM infection with a HR of 7.45 (95% CI = 5.50-10.09). Age-specific comparison showed that the younger NTM patients had a higher HR of RF than the elderly NTM patients (HR: 4.42, 95% CI: 3.28-5.96 vs. HR: 2.52, 95% CI: 2.17-2.92). Comorbidity increased the risk of RF in both cohorts, particularly in those with chronic obstructive pulmonary disease.

CONCLUSION

Our study suggests patients with NTM infection are at a high risk of RF. The risk appears much greater soon after patients diagnosed with NTM infection.

Population-based incidence estimates of influenza-associated respiratory failure hospitalizations, 2003 to 2009

RATIONALE

The incidence of influenza-associated acute respiratory failure is unknown.

OBJECTIVES

To estimate the population-based incidence of influenza-associated acute respiratory failure hospitalizations.

METHODS

This is a cohort study from January 2003 through March 2009 using hospitalization databases for Arizona, California, and Washington from the Healthcare Cost and Utilization Project and influenza surveillance data for regions encompassing these states. Acute respiratory failure requiring mechanical ventilation was defined by International Classification of Diseases-9-CM code. We used negative-binomial regression modeling to estimate the incidence of influenza-associated events.

MEASUREMENTS AND MAIN RESULTS

The incidence of influenza-associated acute respiratory failure was 2.7 per 100,000 person-years (95% confidence interval, 0.2-23.5), and during the influenza season, 3.8% of all respiratory failure hospitalizations were attributable to influenza. Compared with adults aged 18-49 years, the incidence rate ratio for influenza-associated acute respiratory failure was lower among children aged 1-4 (0.9) and 5-17 years (0.3); however, it was higher among adults aged 50-64 (4.8), 65-74 (10.4), 75-84 (19.9), and 85 years and older (33.7). Results were similar with more sensitive and specific outcome definitions and in a sensitivity analysis using only Arizona-specific outcome and surveillance data.

CONCLUSIONS

Our data indicate that influenza was an important contributor to respiratory failure hospitalizations during 2003-2009. Clinicians should maintain a high index of suspicion for influenza among hospitalized patients with acute respiratory illness when influenza is circulating in a community. Influenza has a greater effect on respiratory failure in the elderly, for whom better prevention measures are needed.

Epidemiology and outcomes of acute respiratory failure in the United States, 2001 to 2009: a national survey

BACKGROUND

The objective of this study was to evaluate trends in hospitalization, cost, and short-term outcomes in acute respiratory failure (ARF) between 2001 and 2009 in the United States.

METHODS

Using the Nationwide Inpatient Sample we identified cases of ARF based on International Classification for Diseases, Ninth Revision, Clinical Modification codes. We calculated weighted frequencies of ARF hospitalizations by year and estimated population-adjusted incidence and mortality rates. We used logistic regression to examine hospital mortality rates over time while adjusting for changes in demographic characteristics and comorbidities of patients.

RESULTS

The number of hospitalizations with a diagnosis of ARF rose from 1,007,549 in 2001 to 1,917,910 in 2009, with an associated increase in total hospital costs from $30.1 billion to $54.3 billion. During the same period we observed a decrease in hospital mortality from 27.6% in 2001 to 20.6% in 2009, a slight decline in average length of stay from 7.8 days to 7.1 days, and no significant change in the mean cost per case ($15,900). Rates of mechanical ventilation (noninvasive [NIV] or invasive mechanical ventilation [IMV]) remained stable over the 9-year period, and the use of NIV increased from 4% in 2001 to 10% in 2009.

CONCLUSIONS

Over the period of 2001 to 2009, there was a steady increase in the number of hospitalizations with a discharge diagnosis of ARF, with a decrease in inpatient mortality. There was a significant shift during this time toward the use of NIV, with a decrease in the rates of IMVuse.