Noninvasive ventilation: Are we overdoing it?

Epidemiology and Outcomes of HIN1 Pneumonia in ICU

Introduction

Pandemic influenza H1N1/09 emerged for the first time in April 2009 and has spread widely across India since then. The number of cases have increased over time with the increasing need for respiratory support, causing significant morbidity and mortality. We evaluated the clinical course and outcomes of patients infected with Influenza A (H1N1) admitted to three multidisciplinary intensive care units (ICU) in Chennai.

Materials and methods

We performed a combined retrospective and prospective observational study of all patients admitted with H1N1 pneumonia at three multidisciplinary ICUs in Chennai from October 1, 2018, to January 31, 2019. Data including demographics, risk factors, and clinical courses were recorded. Outcome data including mortality was tracked up to 28 days.

Results

A total of 167 patients were admitted during the study period of which 154 were included in this analysis. The mean age of presentation was 58.2 ± 15.6 years and 59.1% of them were males. The mean acute physiology and chronic health evaluation (APACHE) IV and sequential organ failure assessment (SOFA) scores were 62.8 ± 23.2 and 5.8 ± 3.9 respectively. Oxygen delivery devices were required in 25.3% for a mean duration of 26.5 ± 5.7 hours. Non-invasive ventilation or high-flow nasal cannula (HFNC) was needed in 33.1% of patients for 59.9 ± 64.5 hours. The proportion of patients requiring mechanical ventilation was 41.6%. Rescue measures in the form of proning, use of inhaled nitric oxide (iNO), and extracorporeal membrane oxygenation (ECMO) were initiated for refractory hypoxemia in 26.6%, 14.1%, and 6.3% respectively. The mean duration of ventilator support was 8.5 ± 8 days. Tracheostomy was required in 20.3% of patients and 7.8% were ventilator dependent at 28 days. The mean ICU and Hospital length of stay were 8.3 ± 10.3 and 12.2 ± 14.1 days respectively and overall 28-day mortality was 20.1%.

Conclusion

A significant proportion of H1N1 patients admitted to the ICU required high-level respiratory support including non-invasive ventilation (NIV), HFNC, or invasive ventilation. Deployment of rescue therapies was common and the overall mortality rate was similar to those reported from Western countries.

How to cite this article

Golagana V, Venkataraman R, Mani AK, Rajan ER, Ramakrishnan N, Vidyasagar DD. Epidemiology and Outcomes of HIN1 Pneumonia in ICU. Indian J Crit Care Med 2023;27(7):470-474.

Risk Factors for and Outcomes Associated With Peri-Intubation Hypoxemia: A Multicenter Prospective Cohort Study

BACKGROUND

Little is known about hypoxemia surrounding endotracheal intubation in the critically ill. Thus, we sought to identify risk factors associated with peri-intubation hypoxemia and its effects' on the critically ill.

METHODS

Data from a multicenter, prospective, cohort study enrolling 1,033 critically ill adults who underwent endotracheal intubation across 16 medical/surgical ICUs in the United States from July 2015-January 2017 were used to identify risk factors associated with peri-intubation hypoxemia and its effects on patient outcomes. We defined hypoxemia as any pulse oximetry ≤ 88% during and up to 30 minutes following endotracheal intubation.

RESULTS

In the full analysis (n = 1,033), 123 (11.9%) patients experienced the primary outcome. Five risk factors independently associated with our outcome were identified on multiple logistic regression: cardiac related reason for endotracheal intubation (OR 1.67, [95% CI 1.04, 2.69]); pre-intubation noninvasive ventilation (OR 1.66, [95% CI 1.09, 2.54]); emergency intubation (OR 1.65, [95% CI 1.06, 2.55]); moderate-severe difficult bag-mask ventilation (OR 2.68, [95% CI 1.72, 4.19]); and crystalloid administration within the preceding 24 hours (OR 1.24, [95% CI 1.07, 1.45]; per liter up to 4 liters). Higher baseline S_pO₂ was found to be protective (OR 0.93, [95% CI 0.91, 0.96]; per percent up to 97%). Consistent results were seen in a separate analysis on only stable patients (n = 921, 93 [10.1%]) (those without baseline hypoxemia ≤ 88%). Peri-intubation hypoxemia was associated with in-hospital mortality (OR 2.40, [95% CI 1.33, 4.31]; stable patients: OR 2.67, [95% CI 1.38, 5.17]) but not ICU length of stay (point estimate 0.9 days, [95% CI -1.0, 2.8 days]; stable patients: point estimate 1.5 days, [95% CI -0.4, 3.4 days]) after adjusting for age, body mass index, illness severity, airway related reason for intubation (i.e., acute respiratory failure), and baseline S_PO₂.

CONCLUSIONS

Patients with pre-existing noninvasive ventilation and volume loading who were intubated emergently in the setting of hemodynamic compromise with bag-mask ventilation described as moderate-severe were at increased risk for peri-intubation hypoxemia. Higher baseline oxygenation was found to be protective against peri-intubation hypoxemia. Peri-intubation hypoxemia was associated with in-hospital mortality but not ICU length of stay.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02508948 and Registered Report Identifier: RR2-10.2196/11101.

The benefits of non-invasive ventilation for Community-Acquired Pneumonia: A meta-analysis

BACKGROUND

There is an observed international increase in NIV application as an alternative to endotracheal intubation in non-COPD patients admitted with community acquired pneumonia despite the lack of strong evidence for its use. The aim of this study is the meta-analysis of data from randomised-controlled trials on the effectiveness of non-invasive ventilation versus standard medical care in adults admitted with severe community-acquired pneumonia.

METHODS

Monthly electronic searches on CENTRAL and MEDLINE were performed between September 2017 and October 2019. Only randomized controlled-trials comparing non-invasive ventilation to standard medical care for the treatment of community-acquired pneumonia in adults were eligible for inclusion. The primary outcomes were the rate of endotracheal intubation (ETI) and the proportion of patients meeting the criteria of ETI as defined by the investigators. Secondary outcomes were the ICU and hospital mortality rate. Study eligibility was independently assessed by two investigators. The risk of bias of included studies was assessed using Cochrane's Risk of bias Tool.

RESULTS

Four RCTs involving a total of 218 participants were eligible for inclusion. Results from the meta-analysis showed that NIV significantly reduced rate of ETI (RR = 0.46, 95% CI [0.26, 0.79]), the proportion of patients that met the criteria for ETI (RR = 0.28, 95% CI[0.16, 0.49]) and ICU mortality rate (RR = 0.3, 95% CI[0.09, 0.93]). No significant effect on hospital mortality rate was found (RR = 0.44, 95% CI [0.05, 3.67]). The authors rated quality of evidence based on GRADE criteria as 'Moderate' for the rate of intubation and proportion of patients meeting ETI criteria outcomes, but quality of evidence for ICU and hospital mortality rate as 'Low'.

CONCLUSIONS

This study provides evidence supporting the use of NIV as potential means of avoiding endotracheal intubation and ICU mortality, in patients with acute respiratory failure due to CAP in the critical care setting. However, there is need for further larger international studies.

An observational study on the practice of noninvasive ventilation at a tertiary level Australian intensive care unit

BACKGROUND

Failure of Non-Invasive Ventilation (NIV) is associated with increased morbidity and mortality among critically ill patients. Although there is evidence of association between disease related factors and NIV failure, it is unclear whether factors related to NIV application contribute to NIV failure.

OBJECTIVES

To evaluate NIV failure rate and factors associated with NIV failure.

DESIGN, SETTINGS AND OUTCOMES

Prospective, observational, pilot study conducted in a 23-bed, tertiary care Intensive Care Unit (ICU). NIV failure was defined as application of NIV resulting in intubation or death in ICU.

RESULTS

Amongst 238 patients admitted with respiratory failure, NIV was administered to 60 patients (34 males, 26 females) for a total of 70 application episodes. The etiology of respiratory failure included acute pulmonary edema (28.6%), acute lung injury (22.9%) and pneumonia (15.7%). The mean (SD) age was 62 (17.6) years, BMI 32.0 (8.5) kg/m² and median APACHE-II score 17.5 (14.0-23.8). NIV failure occurred in 22 out of 70 applications (31.4% [95%CI 20.0-43.0]). NIV failure assessed by simple logistic regression analysis, was associated with admission diagnosis (OR 6.0, 95%CI: 1.3-28.7, p = 0.03), use of bi-level NIV-PS (OR 5.00, 95%CI: 1.04-24.1, p = 0.04), presence of nasogastric tube (OR 6.20, 95%CI: 1.9-19.8, p < 0.01) and with short NIV breaks in the 2nd 24-hours (OR 0.96, 95%CI: 0.91-0.99, p = 0.04).

CONCLUSION

NIV failure was observed in 31.4%. Factors associated with NIV failure were etiology of respiratory illness, type of NIV support and short NIV breaks, presumably reflecting illness severity or progress of disease. The presence of a nasogastric tube during application of NIV may adversely impact NIV application.

Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis

PURPOSE

We systematically reviewed the effects of NIV for acute respiratory failure (ARF) in low- and low-middle income countries.

MATERIALS AND METHODS

We searched MEDLINE, CENTRAL, and EMBASE (to January 2016) for observational studies and trials of NIV for ARF or in the peri-extubation period in adults and post-neonatal children. We abstracted outcomes data and assessed quality. Meta-analyses used random-effect models.

RESULTS

Fifty-four studies (ten pediatric/n=1099; 44 adult/n=2904), mostly South Asian, were included. Common diagnoses were pneumonia and chronic obstructive pulmonary disease (COPD). Considering observational studies and the NIV arm of trials, NIV was associated with moderate risks of mortality (pooled risk 9.5%, 95% confidence interval (CI) 4.6-14.5% in children; 16.2% [11.2-21.2%] in adults); NIV failure (10.5% [4.6-16.5%] in children; 28.5% [22.4-34.6%] in adults); and intubation (5.3% [0.8-9.7%] in children; 28.8% [21.9-35.8%] in adults). The risk of mortality was greater (p=0.035) in adults with hypoxemic (25.7% [15.2-36.1%]) vs. hypercapneic (12.8% [7.0-18.6%]) ARF. NIV reduced mortality in COPD (relative risk [RR] 0.47 [0.27-0.79]) and in patients weaning from ventilation (RR 0.48 [0.28-0.80]). The pooled pneumothorax risk was 2.4% (0.8-3.9%) in children and 5.2% (1.0-9.4%) in adults. Meta-analyses had high heterogeneity.

CONCLUSIONS

NIV for ARF in these settings appears to be effective.

Pediatric Noninvasive Ventilation

Noninvasive ventilation has been available for many years for use in the pediatric population. Historically, continuous positive airway pressure and bilevel positive airway pressure modes were used for respiratory diseases, including neonatal apnea, bronchiolitis, asthma, and pneumonia. Newer studies suggest that noninvasive ventilation is also an effective and safe mode for support of children with acute respiratory distress syndrome and respiratory failure. The newest type of noninvasive respiratory support is high flow nasal cannula, which has gained popularity in the past few years and its use is being justified in the literature. Studies have shown that these therapies can decrease the need for intubation and ventilation, decrease length of intensive care days, and increase patient comfort. Additional research is needed to support optimal setting selection and recommendations for the use of noninvasive therapies for infants and children.