Rates and characteristics of intensive care unit admissions and intubations among asthma-related hospitalizations

The adherence to asthma medication for hospitalized children with asthma: A cross-sectional study in a tertiary hospital in Riyadh, Saudi Arabia

AIM

The aim of the study was to assess adherence to asthma controller therapy and factors that influence asthma control and to determine the association between asthma knowledge of the caregiver and asthma control among admitted children with asthma.

SETTINGS AND DESIGN

A cross-sectional study was conducted between November 2022 and May 2023 in a tertiary care hospital. Children with a diagnosis of asthma aged 2-14 years, who were admitted to the hospital with an exacerbation of asthma were identified.

METHODS

Caregivers of the admitted children were interviewed using the Asthma Knowledge Questionnaire and Pediatric Inhaler Adherence Questionnaire.

STATISTICAL ANALYSIS USED

Demographic and clinical data were described using descriptive analyses, where mean and standard deviation were used for normally distributed continuous variables, median and interquartile range (IQR), if otherwise. A P < 0.05 was set as a cutoff for statistical significance.

RESULTS

A total of 144 caregivers completed the survey. Median score for parents' knowledge of asthma was 64%, with an IQR of 59-67. Both mother's and father's educational levels were associated with a good level of knowledge: odds ratio (OR) = 2.48, 95% confidence interval (CI) = 1.1-5.6, and OR = 5.33, 95% CI = 2.23-12.7, respectively. Median adherence to metered dose inhaler (MDI) was 4 (IQR = 2-6). Children who had been admitted to the general ward in the last 6 months were three times more likely to be nonadherent to MDI (OR = 3.03, 95% CI = 1.18-7.82). Forty-three percent of children who were nonadherent to MDI were less likely to have their asthma controlled (OR = 0.43, 95% CI = 0.17-1.06).

CONCLUSION

This study revealed that a low level of knowledge among caregivers of asthma patients is linked to inadequate adherence to asthma controller therapy. As medication adherence is crucial for achieving desirable asthma control and improving the quality of life for this population, efforts need to be made to enhance the knowledge level of parents of children with asthma.

Adherence to National Asthma Guidelines in the Acute Care Setting: A Retrospective Cohort Study

BACKGROUND

Peak flow is a crucial but simple test used to categorize the severity of an episode of an acute exacerbation of asthma. It should be regularly done in all the patients who present with asthma acute exacerbation in the emergency department. The British Thoracic Society (BTS)/Scottish Intercollegiate Guidelines Network (SIGN) guidelines stipulate peak flow use as one of the main tools to categorize acute asthma into moderate, severe, and life-threatening asthma. The BTS and SIGN guidelines also state peak flow is to be utilized in monitoring the disease and to guide in treating patients with acute asthma.

METHODS AND MATERIALS

This study aims to identify the adherence to BTS/SIGN guidelines around the use of peak expiratory flow rate (PEFR) in assessing the severity of patients presenting with acute exacerbation of asthma in a district general hospital. The retrospective cohort study involved collating data between October 2022 and February 2023 from our hospital electronic system. The data collected about the use of PEFR and whether the patients were being classified by severity in presentation following this was compared to the BTS/SIGN 158 asthma guidelines. Following this, the data analysis was done using IBM SPSS Statistics for Windows, Version 21.0 (Released 2012; IBM Corp., Armonk, New York, United States).

RESULTS

Data from 92 patients were collated. PEFR was recorded for 29.3% (n=27) of patients and acute exacerbation of asthma severity was documented in merely 17.4% (n=16) patients.

CONCLUSION

The results indicate a significant proportion of the patient cohort analyzed did not have peak flow readings, there is clear room for improvement, and further intervention is needed in order for the department to adhere to the gold standard guidelines (i.e., BTS/SIGN 158), and thus improve the management and monitoring of acute asthma exacerbations. Future directions can include departmental education, posters as a reminder, and prompts on the electronic system used to alert users to check PEFR when a diagnosis of acute asthma exacerbation is documented.

VV-ECMO as bridge and safety net for successful therapeutic polypragmasy in a case of influenza-triggered near-fatal asthma

Key Clinical Message

In near-fatal asthma, the combination of ECMO therapy and isoflurane application via an intensive care ventilator with an anesthetic conservation device represents a therapeutic combination in seemingly hopeless clinical situations.

Abstract

We report a case of an adult patient with near-fatal asthma, who was implanted venovenous extracorporeal membrane oxygenation in an extern hospital before transfer to our tertiary center. After 13 days and various therapeutic approaches, including inhaled isoflurane therapy via an anesthetic-conserving device, the patient was decannulated and extubated 3 days later.

Magnesium sulfate treatment for acute severe asthma in adults-a systematic review and meta-analysis

Introduction

Add-on magnesium sulfate (MgSO4) for refractory asthma exacerbation has been much debated. The aim of this review and meta-analysis is, therefore, to provide an update on the current evidence for the efficacy of MgSO4 in exacerbations of asthma in adults refractory to standard of care treatment.

Methods

A systematic review was performed in accordance with the PRISMA guidelines. The search was performed in the PubMed database (updated April 2023). For the meta-analysis, a random-effects model was applied using the metaphor package for RStudio (RStudio, Inc.).

Results

A total of 17 randomized controlled trials were included. Three of the nine studies addressing treatment with intravenous (IV) MgSO4 found a significant effect on lung function compared to placebo. Of the eight studies investigating hospital admission rate, only two found a significant effect of MgSO4. Six of the nine studies investigating treatment with nebulized MgSO4 compared to placebo found a favorable effect on forced expiratory volume in 1. second (FEV1) and peak expiratory flow rate (PEF). Only two of the five studies investigating the effect on hospital admission rate found an effect of MgSO4. Comparing effect sizes in a meta-analysis revealed a greater effect on PEF in asthma patients treated with nebulized MgSO4 (MD, 23.57; 95% CI, -2.48 to 49.62, p < 0.01) compared to placebo. The analysis of patients treated with i.v. MgSO4 compared to placebo showed no statistically significant difference (MD, 5.49; 95% CI, -18.67 to 29.65, p = 0.10).

Conclusion

Up to two out of three studies revealed an effect of MgSO4 treatment for asthma exacerbation when assessed by FEV1/PEF, but fewer studies were positive for the outcome of hospital admissions.

Acute severe asthma and its predictors of mortality in rural Southwestern Nigeria: a-five year retrospective observational study

OBJECTIVES

There is an observed paucity of data regarding the predictors of asthma mortality in Nigeria. This study aimed to ascertain the clinical presentations and predictors of acute severe asthma mortality in rural Southwestern Nigeria.

METHODS

A retrospective observational study using a data form and a standardized questionnaire was used to review the 124 patients admitted at Emergency Department between January 2015 and December 2019. The data were analyzed using SPSS Version 22.0. The results were presented in descriptive and tabular formats. Binary logistic regression analysis was used to determine the predictors of asthma mortality and a p-value <.05 was considered statistically significant.

RESULTS

A total of 124 patients were studied. The acute severe asthma mortality was 4.8% and its predictors were older age (Crude odds Ratio (COR), 14.857; 95% CI: 2.489-88.696, p < .001), Tobacco smoking (COR, 6.741; 95% CI: 1.170-38.826, p = .016), more than three co-morbidities (COR, 2.750; 95% CI: 1.147-26.454, p = 0.012), diabetes mellitus (COR, 13.750; 95% CI: 2.380-79.433, p < .001), Human Immunodeficiency virus (COR, 117.000; 95% CI: 9.257-1479.756, p < .001), ≥2 days before presentation (COR, 7.440; 95% CI: 1.288-42.980, p = .039), and Short-acting-B2-agonists overuse (COR, 7.041; 95% CI: 1.005-62.165, p = .044).

CONCLUSION

The mortality rate was 4.8% and its predictors were older age patients, tobacco smoking, multiple co-morbidities, diabetes mellitus, HIV, SP02 <90%, delay presentation, and Short-acting-B2-agonists over use, The study showed that there is high prevalence of asthma mortality in rural Southwestern Nigeria. The findings may be used to plan for asthma preventions and control programs in rural settings, and may also provide an impetus for prospective research on these outcomes.

Extracorporeal Membrane Oxygenation for Refractory Asthma Exacerbations With Respiratory Failure

BACKGROUND

Asthma exacerbations with respiratory failure (AERF) are associated with hospital mortality of 7% to 15%. Extracorporeal membrane oxygenation (ECMO) has been used as a salvage therapy for refractory AERF, but controlled studies showing its association with mortality have not been performed.

RESEARCH QUESTION

Is treatment with ECMO associated with lower mortality in refractory AERF compared with standard care?

STUDY DESIGN AND METHODS

This is a retrospective, epidemiologic, observational cohort study using a national, administrative data set from 2010 to 2020 that includes 25% of US hospitalizations. People were included if they were admitted to an ECMO-capable hospital with an asthma exacerbation, and were treated with short-acting bronchodilators, systemic corticosteroids, and invasive ventilation. People were excluded for age < 18 years, no ICU stay, nonasthma chronic lung disease, COVID-19, or multiple admissions. The main exposure was ECMO vs No ECMO. The primary outcome was hospital mortality. Key secondary outcomes were ICU length of stay (LOS), hospital LOS, time receiving invasive ventilation, and total hospital costs.

RESULTS

The study analyzed 13,714 patients with AERF, including 127 with ECMO and 13,587 with No ECMO. ECMO was associated with reduced mortality in the covariate-adjusted (OR, 0.33; 95% CI, 0.17-0.64; P = .001), propensity score-adjusted (OR, 0.36; 95% CI, 0.16-0.81; P = .01), and propensity score-matched models (OR, 0.48; 95% CI, 0.24-0.98; P = .04) vs No ECMO. Sensitivity analyses showed that mortality reduction related to ECMO ranged from OR 0.34 to 0.61. ECMO was also associated with increased hospital costs in all three models (P < .0001 for all) vs No ECMO, but not with decreased ICU LOS, hospital LOS, or time receiving invasive ventilation.

INTERPRETATION

ECMO was associated with lower mortality and higher hospital costs, suggesting that it may be an important salvage therapy for refractory AERF following confirmatory clinical trials.

Unmet Need for Oral Corticosteroids Use and Exacerbations of Asthma in Primary Care in Taiwan

Patients with asthma are treated in primary healthcare facilities (PHCFs) in Taiwan, where the asthma control status associated with acute exacerbation (AE) and use of oral corticosteroids (OCS) and short-acting β2-agonist (SABA) inhalers remains unclear. A cross-sectional, close-ended, face-to-face questionnaire survey invited board-certified physicians who treat adult asthma patients in PHCFs. The contents of the questionnaire included three parts: rescue OCS to treat AE, regular OCS for asthma control, and AE-related adverse outcomes. There were 445 out of 500 physicians who completed the questionnaire, with 61% of them being non-pulmonologists. A substantial proportion of asthma patients needed rescue OCS or regular OCS each month, or ≥3 canisters of SABA inhalers per year. Approximately 86% of physicians reported their patients with ≥2 AE-related unscheduled visits to clinics or emergency departments in the past year. A total of 41% of physicians reported their patients receiving intubation or intensive care in the past year. A total of 92% of physicians prescribed rescue OCS ≤ 40 mg/day. A total of 92% of physicians prescribed rescue OCS for a duration of ≤7 days for AEs. A total of 85% of physicians prescribed regular OCS ≤ 10 mg/day for asthma control. This is the first study to present the perceptions of asthma-treating physicians on the use of OCS in PHCFs. In summary, 31% of physicians reported ≥ 6% of their patients needed OCS for asthma control and 41% of physicians reported their patients with adverse outcomes in the past year. Thus, the need to improve asthma control in Taiwan is suggested by our study results.

Case report: Isoflurane therapy in a case of status asthmaticus requiring extracorporeal membrane oxygenation

Volatile anesthetics have been described as a rescue therapy for patients with refractory status asthmaticus (SA), and the use of isoflurane for this indication has been reported since the 1980s. Much of the literature reports good outcomes when inhaled isoflurane is used as a rescue therapy for patients for refractory SA. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a mode of mechanical circulatory support that is usually employed as a potentially lifesaving intervention in patients who have high risk of mortality, primarily for underlying pulmonary pathology. VV ECMO is usually only considered in cases where patients gas exchange cannot be satisfactorily maintained by conventional therapy and mechanical ventilation strategies. We report the novel use of isoflurane delivered systemically as treatment for severe refractory SA in a patient on VV ECMO. A 51-year-old male with a history of asthma was transferred from another institution for management of severe SA. He was intubated at the referring hospital after failing non-invasive ventilation. Initial arterial blood gas (ABG) showed pH 7.21, partial pressure of carbon dioxide (PCO2) >95 mmHg, and partial pressure of oxygen (PaO2) 60 mmHg. VV ECMO was initiated on hospital day (HD) 1 due to refractory respiratory acidosis. After ECMO initiation, acid-base status improved, however, severe bronchospasm persisted and intrinsic positive end expiratory pressure (PEEP) was measured at 18 cm H2O. Systemic paralysis was employed, respiratory rate (RR) was reduced to 4 breaths per minute. This degree of bronchospasm did not allow for ECMO weaning. On HD 5, the patient received systemic isoflurane via the ECMO circuit for 20 h. The following morning, intrinsic PEEP was 4 cm H2O, and wheezing improved. He was decannulated from VV ECMO on HD 10 and extubated on HD 17. Inhaled isoflurane therapy in patients on VV ECMO for refractory SA has shown good results, but requires delivery of the medication via anesthesia ventilators. Our case highlights an effective alternative, systemic delivery of anesthetic via the ECMO circuit, as it is often difficult and dangerous to transport these patients to the operating room (OR) or have an intensive care unit (ICU) room adjusted to accommodate an anesthesia ventilator.

Use of ketamine in patients with refractory severe asthma exacerbations: systematic review of prospective studies

PURPOSE

Asthma is a heterogeneous disease with a wide range of symptoms. Severe asthma exacerbations (SAEs) are characterized by worsening symptoms and bronchospasm requiring emergency department visits. In addition to conventional strategies for SAEs (inhaled β-agonists, anticholinergics, and systemic corticosteroids), another pharmacological option is represented by ketamine. We performed a systematic review to explore the role of ketamine in refractory SAEs.

METHODS

We performed a systematic search on PubMed and EMBASE up to August 12th, 2021. We selected prospective studies only, and outcomes of interest were oxygenation/respiratory parameters, clinical status, need for invasive ventilation and effects on weaning.

RESULTS

We included a total of seven studies, five being randomized controlled trials (RCTs, population range 44-92 patients). The two small prospective studies (n = 10 and n = 11) did not have a control group. Four studies focused on adults, and three enrolled a pediatric population. We found a large heterogeneity regarding sample size, age and gender distribution, inclusion criteria (different severity scores, if any) and ketamine dosing (bolus and/or continuous infusion). Of the five RCTs, three compared ketamine to placebo, while one used fentanyl and the other aminophylline. The outcomes evaluated by the included studies were highly variable. Despite paucity of data and large heterogeneity, an overview of the included studies suggests absence of clear benefit produced by ketamine in patients with refractory SAE, and some signals towards side effects.

CONCLUSION

Our systematic review does not support the use of ketamine in refractory SAE. A limited number of prospective studies with large heterogeneity was found. Well-designed multicenter RCTs are desirable.

The use of non- invasive ventilation in asthma exacerbation - a two year retrospective analysis of outcomes

Background: The use of Non-Invasive Ventilation (NIV) in acute asthma exacerbation remains controversial. Comparative data on patient characteristics that benefit from NIV in asthma exacerbation to those patients that fail NIV remains limited. Our study compares some of these patient characteristics and examines if NIV is safe and effective in carefully selected patients.

Methods: Following institutional review board approval, we extracted from the electronic medical record and conducted a retrospective chart-based review of those patients who received NIV in the emergency room for a diagnosis of asthma exacerbation from January 2017 to December 2018.

Results and Conclusion: The rate of failure of NIV overall was low, at 9.17%, with younger patients more likely to fail NIV (P = 0.03) and need invasive mechanical ventilation. Surprisingly, baseline asthma severity did not impact NIV failure rate, and neither did body mass index, smoking history, and a host of clinical characteristics. Understandably, the length of stay was significantly longer in the group of patients that failed NIV. There were no adverse events, such as an increased rate of barotrauma events in either group. In conclusion, this study contributes to the growing body of evidence that NIV is a safe and effective adjunct to routine care in the management of patients with asthma exacerbation.

Will the asthma revolution fostered by biologics also benefit adult ICU patients?

PURPOSE

Asthma exacerbations are inflammatory events that rarely result in full hospitalization following an ER visit. Unfortunately, certain patients require prolonged support, including occasional external lung support through ECMO or ECCOR (with subsequent further exposure to other life-threatening issues), and some die. In parallel, biologics are revolutionizing severe asthma management, mostly in T2 high patients.

METHODS

We extensively reviewed the current unmet needs surrounding ICU-admitted asthma exacerbations, with a focus on currently available drugs and the underlying biological processes involved. We explored whether currently available T2-targeting drugs can reasonably be seen as potential players not only for relapse prevention but also as candidate drugs for a faster resolution of such episodes. The patient's perspective was also sought.

RESULTS

About 30% of asthma exacerbations admitted to the ICU do not resolve within five days. Persistent severe airway obstruction despite massive doses of corticosteroids and maximal pharmacologically induced bronchodilation is the main cause of treatment failure. Previous ICU admission is the main risk factor for such episodes and may eventually be considered as a T2 surrogate marker. Fatal asthma cases are hallmarked by poorly steroid-sensitive T2-inflammation associated with severe mucus plugging. New, fast-acting T2-targeting biologics (already used for preventing asthma exacerbations) have the potential to circumvent steroid sensitivity pathways and decrease mucus plugging. This unmet need was confirmed by patients who reported highly negative, traumatizing experiences.

CONCLUSIONS

There is room for improvement in the management of ICU-admitted severe asthma episodes. Clinical trials assessing how biologics might improve ICU outcomes are direly needed.

Decapneization as supportive therapy for the treatment of status asthmaticus: a case report

Background

Acute severe asthma is a life-threatening medical emergency. Characteristics of asthma include increased airway resistance and dynamic pulmonary hyperinflation that can manifest in dangerous levels of hypercapnia and acidosis, with significant mortality and morbidity. Severe respiratory distress can lead to endotracheal intubation followed by mechanical ventilation, which can cause increased air trapping with dynamic hyperinflation, predisposing the lungs to barotraumas.

Case presentation

The present case report describes the use of the minimally invasive ECCO₂R ProLUNG^® (Estor) with protective low-tidal-volume ventilation, in a Caucasian patient with near-fatal asthma and with no response to conventional therapy.

Conclusions

Since hypercarbia rather than hypoxemia is the primary abnormality in status asthmaticus, a rescue therapeutic strategy combining the ECCO₂R membrane ProLUNG^® (Estor) with ultra-protective low-tidal-volume ventilation can be successfully applied to limit the risk of severe barotrauma during invasive mechanical ventilation. ECCO₂R ProLUNG^® is a partial respiratory support technique that, based on the use of an extracorporeal circuit with a gas-exchange membrane, achieves relevant CO₂ clearance directly from the blood using double-lumen venous-venous vascular access, at blood flow in the range of 0.4–1.0 L/minute.

Difficulty Ventilating: A Case Report on Ventilation Considerations of an Intubated Asthmatic Undergoing Air Medical Critical Care Transport

The air medical transport of intubated patients is a high-risk mission that requires preplanning before helicopter launch. This case describes a scenario in which the helicopter emergency medical services (HEMS) team was unable to ventilate a patient because of the mechanical limitations of the transport ventilator. The HEMS mission was ultimately aborted, and the patient had to be transported by a ground crew equipped with a hospital-based ventilator. In addition to the optimal medical management of the patient in status asthmaticus, critical care transport crews must be familiar with the treatment of patients exhibiting extremely high peak airway pressures. Specifically, ventilator manipulations as well as the technical specifications of the transport ventilator may preclude the patient from being transported by the HEMS team. It is imperative that the patient's current ventilator setting be evaluated before the launch of the aircraft to prevent any possible delays in patient care.

Predicting the requiring intubation and invasive mechanical ventilation among asthmatic exacerbation-related hospitalizations

OBJECTIVE

To identify the predictors of requiring intubation and invasive mechanical ventilation (IMV) in asthmatic exacerbation (AE)-related hospitalizations.

METHODS

This study was conducted in southern Thailand between October 2016 and September 2018. The characteristics and clinical findings of patients admitted for AE requiring intubation and IMV were analyzed. The variables were evaluated by univariate and multivariate analysis to identify the independent predictors.

RESULTS

A total of 509 patients with a median age of 53 years were included in the study. Being female (60.2%), having no previous use of a controller (64.5%), having a history of smoking, and having a high level of white blood cell count (14,820 cells/mm³) were the significantly more common characteristics of the patients requiring mechanical ventilation. Univariate analysis showed that being male (OR = 1.96 95% CI, 1.22-3.13), having a history of 1-2 AEs in the past 12 months (OR = 3.27 95% CI, 1.75-6.12), and having an absolute eosinophil count ≥300 cells/mm³ (OR = 1.68 95% CI, 1.05-2.69) were associated with patients requiring IMV, whereas the patients who were taking a reliever (OR = 0.36 95% CI, 0.23-0.57) and controller (OR = 0.42 95% CI, 0.27-0.68) were associated with a decreased risk of requiring intubation and IMV. In multivariate analysis, only 1-2 AEs within the past 12 months (OR = 3.12, 95% CI, 1.19-8.21) was an independent predictor of requiring intubation and IMV in patients with AE-related hospitalization (p = 0.021).

CONCLUSIONS

This study found that a history of 1-2 AEs in the past 12 months was a strong independent predictor for the requirement of intubation and IMV in patients hospitalized for AE-related conditions.

Noninvasive Ventilation Use in Critically Ill Patients with Acute Asthma Exacerbations

Rationale: Noninvasive ventilation decreases the need for invasive mechanical ventilation and mortality among patients with chronic obstructive pulmonary disease but has not been well studied in asthma.Objectives: To assess the association between noninvasive ventilation and subsequent need for invasive mechanical ventilation and in-hospital mortality among patients admitted with asthma exacerbation to the ICU.Methods: We performed a retrospective cohort study using administrative data collected during 2010-2017 from 682 hospitals in the United States. Outcomes included receipt of invasive mechanical ventilation and in-hospital mortality. Generalized estimating equations, propensity-matched models, and marginal structural models were used to assess the association between noninvasive ventilation and outcomes.Measurements and Main Results: The study population included 53,654 participants with asthma exacerbation. During the study period, 13,540 patients received noninvasive ventilation (25.2%; 95% confidence interval [CI], 24.9-25.6%), 14,498 underwent invasive mechanical ventilation (27.0%; 95% CI, 26.7-27.4%), and 1,291 died (2.4%; 95% CI, 2.3-2.5%). Among those receiving noninvasive ventilation, 3,013 patients (22.3%; 95% CI, 21.6-23.0%) required invasive mechanical ventilation after first receiving noninvasive ventilation, 136 of whom died (4.5%; 95% CI, 3.8-5.3%). Across all models, the use of noninvasive ventilation was associated with a lower odds of receiving invasive mechanical ventilation (adjusted generalized estimating equation odds ratio, 0.36; 95% CI, 0.32-0.40) and in-hospital mortality (odds ratio, 0.48; 95% CI 0.40-0.58). Those who received noninvasive ventilation before invasive mechanical ventilation were more likely to have comorbid pneumonia and severe sepsis.Conclusions: Noninvasive ventilation use during asthma exacerbation was associated with improved outcomes but should be used cautiously with acute comorbid conditions.

How to ventilate obstructive and asthmatic patients

Exacerbations are part of the natural history of chronic obstructive pulmonary disease and asthma. Severe exacerbations can cause acute respiratory failure, which may ultimately require mechanical ventilation. This review summarizes practical ventilator strategies for the management of patients with obstructive airway disease. Such strategies include non-invasive mechanical ventilation to prevent intubation, invasive mechanical ventilation, from the time of intubation to weaning, and strategies intended to prevent post-extubation acute respiratory failure. The role of tracheostomy, the long-term prognosis, and potential future adjunctive strategies are also discussed. Finally, the physiological background that underlies these strategies is detailed.

A population-based observational study of patients with pulmonary disorders in intensive care unit

BACKGROUND/AIMS

Only a few epidemiologic studies on the patients with pulmonary disorders admitted to intensive care unit exist. We investigated the characteristics and clinical outcomes of the patients with severe pulmonary disorders.

METHODS

The sample cohort database of National Health Insurance Sharing Service from 2006 to 2015 was used. Operational definition of critically ill patients was adults who were either admitted to intensive care unit for at least 3 days or expired within first 2 days in the unit. The pulmonary disorder group comprised of critically ill patients with respiratory disease as the main diagnosis.

RESULTS

Among the 997,173 patients, 12,983 (1.3%) in 383 intensive care units were categorized as critically ill. Patients in the pulmonary disorder group tended to have more comorbidities or disabilities. The length of hospital stay and duration of mechanical ventilation were longer in the pulmonary disorder group. Overall mortality and re-admission were higher in the pulmonary disorder group, with adjusted incidence rate ratios of 1.22 (95% confidence interval, 1.18 to 1.27) and 1.26 (95% confidence interval, 1.17 to 1.36), respectively. After adjustment by Cox regression, the pulmonary disorder group was an independent risk factor for in-hospital mortality.

CONCLUSION

In critically ill patients with pulmonary disorder, the use of healthcare resources was higher, and their clinical outcomes were significantly worse than the non-pulmonary disorder group.

Physiologically variable ventilation in a rabbit model of asthma exacerbation

BACKGROUND

Mechanical ventilation during status asthmaticus is challenging and increases the risk of severe complications. We recently reported the value of physiologically variable ventilation (PVV) in healthy and acutely injured lungs. We investigated whether PVV provides benefits compared with pressure-controlled ventilation (PCV) in an experimental model of severe acute asthma.

METHODS

Allergen-sensitised rabbits were anaesthetised and randomised to either PCV (n=10) or PVV (n=12) during sustained bronchoconstriction induced by allergen and cholinergic stimuli for 6 h. The PVV pattern was generated from pre-recorded spontaneous breathing. Ventilation parameters, oxygenation index (PaO₂/FiO₂), and respiratory mechanics were measured hourly. Histological injury and inflammation were quantified after 6 h of ventilation.

RESULTS

PVV resulted in lower driving pressures (13.7 cm H₂O [12.5-14.9], mean [95% confidence interval]), compared with pressure-controlled ventilation (17.6 cm H₂O [15.4-19.8]; P=0.002). PVV improved PaO₂/FiO₂ (PVV: 55.1 kPa [52-58.2]; PCV: 45.6 kPa [39.3-51.9]; P=0.018) and maintained tissue elastance (PVV: +8.7% [-0.6 to 18]; PCV: -11.2% [-17.3 to -5.1]; P=0.03). PVV resulted in less lung injury as assessed by lower histological injury score (PVV: 0.65 [0.62-0.65]; PCV: 0.71 [0.69-0.73]; P=0.003), cell count (PVV: 247 10⁴ ml^-1 [189-305]; PCV: 447 10⁴ ml^-1 [324-570]; P=0.005), and protein concentration in bronchoalveolar lavage fluid (PVV: 0.14 μg ml^-1 [0.10-0.18]; PCV: 0.21 μg ml^-1 [0.15-0.27]; P=0.035).

CONCLUSIONS

Applying physiological variable ventilation in a model of asthma exacerbation led to improvements in gas exchange, ventilatory pressures, and respiratory tissue mechanics, and reduced lung injury. A global reduction in lung shear stress and recruitment effects may explain the benefits of PVV in status asthmaticus.

Acute severe asthma requiring invasive mechanical ventilation in the era of modern resuscitation techniques: A 10-year bicentric retrospective study

Purpose

Patients with acute severe asthma (ASA) may in rare cases require invasive mechanical ventilation (IMV). However, recent data on this issue are lacking.

Materials and methods

In this retrospective and bicentric study conducted on a 10 year period, we investigate the in-hospital mortality in patients with ASA requiring IMV. We compare this mortality to that of patients with other types of respiratory distress using a standardized mortality ratio (SMR) model.

Results

Eighty-one episodes of ASA requiring IMV were evaluated. Factors significantly associated with in-hospital mortality were cardiac arrest on day of admission, cardiac arrest as the reason for intubation, absence of decompensation risk factors, need for renal replacement therapy on day of admission, and intubation in pre-hospital setting. Non-survivors had higher SAPS II, SOFA, creatinine and lactate levels as well as lower blood pressure, pH, and HCO₃ on day of admission. In-hospital mortality was 15% (n = 12). Compared to a reference population of 2,670 patients, the SMR relative to the SAPS II was very low at 0.48 (95% CI, 0.25–0.84). The only factor independently associated with in-hospital mortality was cardiac arrest on day of admission. In-hospital mortality was 69% in patients with cardiac arrest on day of admission and 4% in others (p < 0.01). Salvage therapies were given to 7 patients, sometimes in combination with each other: ECMO (n = 6), halogenated gas (n = 1) and anti-IL5 antibody (n = 1). Death occurred in only 2 of these 7 patients, both of whom had cardiac arrest on day of admission.

Conclusion

Nowadays, the mortality of patients with ASA requiring IMV is low. Death is due to multi-organ failure, with cardiac arrest on day of admission being the most important risk factor. In patients who did not have cardiac arrest on day of admission the mortality is even lower (4%) which allows an aggressive management.

Pharmacotherapeutic strategies for critical asthma syndrome: a look at the state of the art

INTRODUCTION

'Critical Asthma Syndrome' (CAS) is an umbrella term proposed to include several forms of asthma, responsible for acute and life-threatening exacerbations. CAS requires urgent and adequate supportive and pharmacological treatments to prevent serious outcomes.

AREAS COVERED

The purpose of this review is to discuss current knowledge on the pharmacotherapeutic strategies for treatment of CAS.

EXPERT OPINION

Airflow limitation, airway wall edema, and mucus plugs are the pathophysiological targets of pharmacological therapies. Strategies to achieve these goals are based on the use of various classes of drugs. Inhaled beta2-agonists are the mainstay of the initial therapy of CAS. Inhaled anticholinergic agents may be considered in the treatment of CAS in addition to beta 2 agonists. Systemic corticosteroids should be administered as soon as possible in order to counteract airway inflammation and restore normal airway sensitivity. The effectiveness of pharmacological therapies in CAS is linked not only to the timely use of drugsbut also to the dosage and route of administration. Early recognition and aggressive treatment are essential for the management of CAS; however, prevention is the best cure. Although significant progress has been made, further efforts are needed to implement an optimal exacerbation prevention strategy.

Impact of asthma control on different age groups in five Latin American countries

Background

Asthma is a chronic airway inflammatory condition of the airway and is classified as controlled, partially controlled, and uncontrolled. Patients with uncontrolled asthma are at greater risk for hospitalizations and visits to emergencies, and the condition has greater impact on their daily lives. The aim of this study was to evaluate asthma control, the use of health resources, and asthma's impact on the activities of daily living of patients with different age groups in 5 Latin American countries.

Methods

This was a retrospective analysis of The Latin America Asthma Insights and Management (LA AIM) study carried out in Argentina, Brazil, Mexico, Venezuela, and Puerto Rico. Asthmatics were splited into 3 age groups: 12–17, >17–40 and > 40 years old. An interview face to face was carried out and patients answered a questionnaire of 53 questions related to 5 main domains of asthma: symptoms, impact of asthma on daily living activities, patients' perceptions of asthma control, exacerbations, and treatment/medication.

Results

A total of 2167 asthmatics were interviewed. There was a low percentage of controlled patients (mean 9%) in all 3 groups with no particular difference among the five countries, but Venezuelan patients had a 71% chance of having uncontrolled asthma (p < 0.001).

Conclusion

In the 3 age groups, patients experienced poor asthma control, with no significant differences among the countries. Patients who used control medication had a greater chance of controlling their asthma, and those who had emergency health care visits had a greater chance of having uncontrolled asthma.

Evaluation and management of the critically ill adult asthmatic in the emergency department setting

INTRODUCTION

Asthma is a common reason for presentation to the Emergency Department and is associated with significant morbidity and mortality. While patients may have a relatively benign course, there is a subset of patients who present in a critical state and require emergent management.

OBJECTIVE

This narrative review provides evidence-based recommendations for the assessment and management of patients with severe asthma.

DISCUSSION

It is important to consider a broad differential diagnosis for the cause and potential mimics of asthma exacerbation. Once the diagnosis is determined, the majority of the assessment is based upon the clinical examination. First line therapies for severe exacerbations include inhaled short-acting beta agonists, inhaled anticholinergics, intravenous steroids, and magnesium. Additional therapies for refractory cases include parenteral epinephrine or terbutaline, helium‑oxygen mixture, and consideration of ketamine. Intravenous fluids should be administered, as many of these patients are dehydrated and at risk for hypotension if they receive positive pressure ventilatory support. Noninvasive positive pressure ventilation may prevent the need for endotracheal intubation. If mechanical ventilation is required, it is important to avoid breath stacking by setting a low respiratory rate and allowing permissive hypercapnia. Patients with severe asthma exacerbations will require intensive care unit admission.

CONCLUSIONS

This review provides evidence-based recommendations for the assessment and management of severe asthma with a focus on the emergency clinician.

Extracorporeal carbon dioxide removal in heart-beating donor with acute severe asthma: A case report

Status asthmaticus is a life-threatening disorder that can manifest in dangerous levels of hypercapnia and acidosis. The use of extracorporeal carbon dioxide removal (ECCO2R) has been used successfully to control pH and PaCO₂ in patients with acute severe asthma. The present report describes the use of this technology in near-fatal asthma with brain death, and awaiting organ harvest. The ProLUNG® system consists of a veno-venous hemoperfusion circuit with an artificial lung polymethylpentene membrane coated with phosphorylcholine with a surface of 1.81 m². The system can reach a blood flow of 450 ml/min trough a double-lumen central venous catheter (13.0 Fr) placed in femoral, subclavian or jugular vein. The platform is provided with automated management of airflow and VCO₂ monitoring during treatment. The patient was maintained on extracorporeal treatment ensuring stable arterial pH control and PaCO₂ control. In acute status asthmaticus, complicated with cardiac arrest, mini-invasive ECCO2R was an effective method of controlling pH and PaCO₂, for optimizing hemodynamic and aerobic metabolism and for performing protective ventilation for an optimal organ donor preservation until the organ harvest occurs.

Continuous Albuterol in Pediatric Acute Care: Study Demonstrates Safety Outside the Intensive Care Unit

There are little data to support the use of continuous aerosolized albuterol (CAA) in the non-intensive care unit (ICU) or non-emergency department (ED) setting for pediatric asthma patients. A 2014 study demonstrated low rates of adverse outcomes associated with administration of CAA on the acute care unit; however, the authors do not describe additional outcomes. We sought to determine whether administration of CAA within a respiratory cohort on an acute care floor was feasible and safe.

Management of severe asthma exacerbation: guidelines from the Société Française de Médecine d'Urgence, the Société de Réanimation de Langue Française and the French Group for Pediatric Intensive Care and Emergencies

BACKGROUND

The French Emergency Medicine Society, the French Intensive Care Society and the Pediatric Intensive Care and Emergency Medicine French-Speaking Group edited guidelines on severe asthma exacerbation (SAE) in adult and pediatric patients.

RESULTS

The guidelines were related to 5 areas: diagnosis, pharmacological treatment, oxygen therapy and ventilation, patients triage, specific considerations regarding pregnant women. The literature analysis and formulation of the guidelines were conducted according to the Grade of Recommendation Assessment, Development and Evaluation methodology. An extensive literature research was conducted based on publications indexed in PubMed™ and Cochrane™ databases. Of the 21 formalized guidelines, 4 had a high level of evidence (GRADE 1+/-) and 7 a low level of evidence (GRADE 2+/-). The GRADE method was inapplicable to 10 guidelines, which resulted in expert opinions. A strong agreement was reached for all guidelines.

CONCLUSION

The conjunct work of 36 experts from 3 scientific societies resulted in 21 formalized recommendations to help improving the emergency and intensive care management of adult and pediatric patients with SAE.

Critical Care Interventions for Asthmatic Patients Admitted From the Emergency Department to the Pediatric Intensive Care Unit

OBJECTIVES

The aim of this study was to assess the frequency and predictors of critical interventions in asthmatic patients admitted to the pediatric intensive care unit (PICU) at a tertiary-care pediatric hospital.

METHODS

We conducted a retrospective chart review of patients admitted from our emergency department (ED) to the PICU for treatment of status asthmaticus between January 1, 2008, and March 31, 2013. Patients with concomitant medical conditions and those who received a critical intervention, other than continuously aerosolized albuterol, in the ED before admission were excluded. Data collected included patient demographics, clinical characteristics including clinical asthma scores (CASs), hospital course, and adverse events.

RESULTS

A total of 384 patients were included in the analyses (mean age, 8.2 ± 4.5 years). Thirty-four patients (8.9%) received at least 1 critical intervention. No patients were intubated, had central venous catheter placement, and developed circulatory collapse or pneumothoraxes. Independent predictors associated with an increased likelihood of receiving a critical intervention included age above 8 years (odds ratio [OR], 4.3; 95% confidence interval [CI], 1.9-9.4), previous PICU admission (OR, 3.2; 95% CI, 1.5-6.6), altered mental status on ED arrival (OR, 4.5; 95% CI, 1.5-13.4), CAS on ED arrival of 5 or greater (OR, 3.4; 95% CI, 1.3-9.1), and CAS on PICU admission of 5 or greater (OR, 4.3; 95% CI, 1.8-10.2).

CONCLUSIONS

Patients admitted to the PICU for status asthmaticus infrequently require critical interventions if they have not been initiated in the ED. Patients with a CAS of less than 5 may be safely managed with continuously aerosolized albuterol on non-critical care units with low risk for clinical deterioration.

Outcomes of paediatric critical care asthma patients

AIM

The aim of this study was to characterise patients with asthma admitted to an Australian paediatric intensive care unit (PICU).

METHODS

This was a retrospective review of patients with asthma admitted to a university-affiliated, 23-bed, tertiary PICU between January 2000 and December 2011, with a subset of pharmacotherapy and biochemical data from patients admitted between July 2007 and December 2011.

RESULTS

A total of 589 admissions (501 patients) with asthma over 12 years constituted 4.4% of all PICU admissions. Three patients died (0.6%). Non-invasive ventilation (NIV) was used in 104 (17.7%) admissions, and 41 (7%) were invasively ventilated. On 12 (2%) occasions, patients received both NIV and invasive ventilation. Over 12 years, there was a significant trend to increased use of NIV, 11-39% (P < 0.0001), and invasive ventilation, 6-14% (P < 0.001). All received steroids and nebulised β2-agonists. A total of 92% received intravenous (IV) β2-agonists, 65% of these for less than 12 h. PICU and hospital stay were proportional to the duration of IV β2-agonist infusion (P < 0.0001). A total of 47.1% received IV magnesium sulphate, increasing from 19 to 75% (P < 0.001). The majority (48%) were transferred directly to PICU from other hospitals. Median PICU stay was 1.04 days (0.72-1.63); hospital stay was 3.16 days (2.29-4.71), and both were unchanged.

CONCLUSIONS

Intensive care length of stay (LOS) was unchanged over 12 years. Both invasive and NIV and IV magnesium sulphate use increased. LOS was directly related to the duration of IV β2-agonist. Asthma patients admitted to PICU typically have a brief stay and have a fairly predictable course. Prospective studies could explore the contribution of IV agents and the role of NIV.

Variable ventilation decreases airway responsiveness and improves ventilation efficiency in a rat model of asthma

The optimal ventilation strategy in patients receiving mechanical ventilation for severe asthma remains unclear. The effect of conventional ventilation (with constant tidal volume and respiratory rate) and variable ventilation (with the same average but variable tidal volume and respiratory rate) on peak airway pressure and airway exacerbation induced by increasing doses of methacholine was compared in a rat model of asthma. The respiratory rate and tidal volume data were obtained from a spontaneously breathing intact rat during immobility using a whole-body plethysmograph. Peak airway pressure and airway responsiveness to cumulative doses of methacholine were significantly affected by ventilation mode and they were lower in variable ventilation group than in the conventional ventilation group. Also, variable ventilation improved oxygen saturation compared to conventional ventilation. Our results indicate that variable ventilation decreases airway responsiveness and enhances ventilation efficiency in a rat model of asthma. We suggest further investigations on beneficial effects of variable ventilation strategy in mechanically ventilated patients with severe asthma.

Ohio Pediatric Asthma Repository: Opportunities to Revise Care Practices to Decrease Time to Physiologic Readiness for Discharge

BACKGROUND

Large-scale, multisite studies in which researchers evaluate patient- and systems-level factors associated with pediatric asthma exacerbation outcomes are lacking. We sought to investigate patient-level risks and system-level practices related to physiologic readiness for discharge (PRD) in the prospective Ohio Pediatric Asthma Repository.

METHODS

Participants were children ages 2 to 17 years admitted to an Ohio Pediatric Asthma Repository hospital for asthma exacerbation. Demographics, disease characteristics, and individual hospital practices were collected. The primary outcome was PRD timing (hours from admission or emergency department [ED] presentation until the first 4-hour albuterol spacing).

RESULTS

Data for 1005 participants were available (865 ED presentations). Several nonstandard care practices were associated with time to PRD (P < .001). Continuous pulse oximetry was associated with increased time to PRD (P = .004). ED dexamethasone administration was associated with decreased time to PRD (P < .001) and less ICU admittance and intravenous steroid use (P < .0001). Earlier receipt of chest radiograph, antibiotics, and intravenous steroids was associated with shorter time to PRD (P < .05). Care practices associated with shorter time to PRD varied markedly by hospital.

CONCLUSIONS

Substantial variation in care practices for inpatient asthma treatment exists among children's hospital systems in Ohio. We found several modifiable, system-level factors and therapies that contribute to PRD that warrant further investigation to identify the best and safest care practices. We also found that there was no standardized measure of exacerbation severity used across the hospitals. The development of such a tool is a critical gap in current practice and is needed to enable definitive comparative effectiveness studies of the management of acute asthma exacerbation.

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

RATIONALE

Little is known about the effectiveness of noninvasive ventilation for patients hospitalized with asthma exacerbation.

OBJECTIVES

To assess clinical outcomes of noninvasive (NIV) and invasive mechanical ventilation (IMV) and examine predictors for NIV use in patients hospitalized with asthma.

METHODS

This was a retrospective cohort study at 97 U.S. hospitals using an electronic medical record database. We developed a hierarchical regression model to identify factors associated with the choice of initial ventilation and used the Laboratory Acute Physiological Score to adjust for differences in the severity of illness. We assessed the outcomes of patients treated with initial NIV or IMV in a propensity-matched cohort.

MEASUREMENTS AND MAIN RESULTS

Among 13,930 subjects, 73% were women and 54% were white. The median age was 53 years. Overall, 1,254 patients (9%) required ventilatory support (NIV or IMV). NIV was the initial ventilation method for 556 patients (4.0%) and IMV for 668 (5.0%). Twenty-six patients (4.7% of patients treated with NIV) had to be intubated (NIV failure). The in-hospital mortality was 0.2, 2.3, 14.5, and 15.4%, and the median length of stay was 2.9, 4.1, 6.7, and 10.9 days among those not ventilated, ventilated with NIV, ventilated with IMV, and with NIV failure, respectively. Older patients were more likely to receive NIV (odds ratio, 1.06 per 5 yr; 95% confidence interval [CI], 1.01-1.11), whereas those with higher acuity (Laboratory Acute Physiological Score per 5 units: odds ratio, 0.85; 95% CI, 0.82-0.88) and those with concomitant pneumonia were less likely to receive NIV. In a propensity-matched sample, NIV was associated with a lower inpatient risk of dying (risk ratio, 0.12; 95% CI, 0.03-0.51) and shorter lengths of stay (4.3 d less; 95% CI, 2.9-5.8) than IMV.

CONCLUSIONS

Among patients hospitalized with asthma exacerbation and requiring ventilatory support (NIV or IMV), more than 40% received NIV. Although patients successfully treated with NIV appear to have better outcomes than those treated with IMV, the low rate of NIV failure suggests that NIV was being used selectively in a lower risk group. The increased risk of mortality for patients who fail NIV highlights the need for careful monitoring to avoid possible delay in intubation.

Mechanically Ventilating the Severe Asthmatic

The management of the critically ill patients with asthma can be rather challenging. Potentially devastating complications relating to this presentation include hypoxemia, worsening bronchospasm, pulmonary aspiration, tension pneumothorax, dynamic hyperinflation, hypotension, dysrhythmias, and seizures. In contrast to various other pathologies requiring mechanical ventilation, acute asthma is generally associated with better outcomes. This review serves as a practical guide to the physician managing patients with severe acute asthma requiring mechanical ventilation. In addition to specifics relating to endotracheal intubation, we also discuss the interpretation of ventilator graphics, the recommended mode of ventilation, dynamic hyperinflation, permissive hypercapnia, as well as the role of extracorporeal membrane oxygenation and noninvasive mechanical ventilation.

Prognostic nomogram for inpatients with asthma exacerbation

Background

Asthma exacerbation may require a visit to the emergency room as well as hospitalization and can occasionally be fatal. However, there is limited information about the prognostic factors for asthma exacerbation requiring hospitalization, and no methods are available to predict an inpatient’s prognosis. We investigated the clinical features and factors affecting in-hospital mortality of patients with asthma exacerbation and generated a nomogram to predict in-hospital death using a national inpatient database in Japan.

Methods

We retrospectively collected data concerning hospitalization of adult patients with asthma exacerbation between July 2010 and March 2013 using the Japanese Diagnosis Procedure Combination database. We recorded patient characteristics and performed Cox proportional hazards regression analysis to assess the factors associated with all-cause in-hospital mortality. Then, we constructed a nomogram to predict in-hospital death.

Results

A total of 19,684 patients with asthma exacerbation were identified; their mean age was 58.8 years (standard deviation, 19.7 years) and median length of hospital stay was 8 days (interquartile range, 5–12 days). Among study patients, 118 died in the hospital (0.6%). Factors associated with higher in-hospital mortality included older age, male sex, reduced level of consciousness, pneumonia, and heart failure. A nomogram was generated to predict the in-hospital death based on the existence of seven variables at admission. The nomogram allowed us to estimate the probability of in-hospital death, and the calibration plot based on these results was well fitted to predict the in-hospital prognosis.

Conclusion

Our nomogram allows physicians to predict individual risk of in-hospital death in patients with asthma exacerbation.

Noninvasive ventilation for acute exacerbations of asthma: A systematic review of the literature

BACKGROUND

Asthma is a chronic disease characterised by reversible airway obstruction caused by bronchospasm, mucous and oedema. People with asthma commonly experience acute exacerbations of their disease requiring hospitalisation and subsequent utilisation of economic and healthcare resources. Noninvasive ventilation has been suggested as a treatment for acute exacerbations of asthma due to its ability to provide airway stenting, optimal oxygen delivery and decreased work of breathing.

OBJECTIVES

This paper is a systematic review of the available published research focused on the use of noninvasive ventilation for the treatment of acute exacerbations of asthma to determine if this treatment provides better outcomes for patients compared to standard medical therapy.

METHOD

Database searches were conducted using EBSCOhost, MEDLINE and PubMed. Search terms used were combinations of 'noninvasive ventilation', 'BiPAP', 'CPAP', 'wheez*' and 'asthma'. Articles were included if they were research papers focused on adult patients with asthma and a treatment of noninvasive ventilation, and were published in full text in English. Included articles were reviewed using the National Health and Medical Research Council (Australia) evidence hierarchy and quality appraisal tools.

RESULTS

There were 492 articles identified from the database searches. After application of inclusion/exclusion criteria 13 articles were included in the systematic review. Studies varied significantly in design, endpoints and outcomes. There was a trend in better outcomes for patients with acute asthma who were treated with noninvasive ventilation compared to standard medical therapy, however, the variability of the studies meant that no conclusive recommendations could be made.

CONCLUSION

More research is required before noninvasive ventilation can be conclusively recommended for the treatment of acute exacerbations of asthma.

Endotracheal Intubation after Acute Drug Overdoses: Incidence, Complications, and Risk Factors

BACKGROUND

Drug overdose is the leading cause of injury-related fatality in the United States, and respiratory failure remains a major source of morbidity and mortality.

OBJECTIVES

We aimed to identify the incidence and risk factors for endotracheal intubation after acute drug overdose.

METHODS

This secondary data analysis was performed on a 5-year prospective cohort at two urban tertiary-care hospitals. The present study analyzed adult patients with suspected acute drug overdose to derive independent clinical predictors of endotracheal intubation.

RESULTS

We analyzed 2497 patients with acute drug overdose, of whom 87 (3.5%) underwent endotracheal intubation. Independent clinical risk factors for endotracheal intubation were: younger age (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.96-0.98), and history of obstructive lung disease (OR 6.6, 95% CI 3.5-12.3); however, heart failure had no association. Patients with obstructive lung disease had significantly more hypercapnia (mean difference 6.8 mm Hg, 95% CI 2.3-11.3) and a higher degree of acidemia (mean pH difference 0.04, 95% CI 0.01-0.07) than patients without obstructive lung disease. Lack of rapid sequence sedative/paralytic was associated with in-hospital fatality. Early complications of endotracheal intubation itself included desaturation (3.4%) and bradycardia (1%).

CONCLUSIONS

Endotracheal intubation was infrequently performed on patients with acute drug overdose, and complications were rare when performed. Risk factors associated with endotracheal intubation included younger age and prior obstructive lung disease.

Managing Respiratory Failure in Obstructive Lung Disease

Exacerbations of obstructive lung disease are common causes of acute respiratory failure. Short-acting bronchodilators and systemic glucocorticoids are the foundation of pharmacologic management. For patients requiring ventilator support, use of noninvasive ventilation reduces the risk of mortality and progression to invasive mechanical ventilation. Challenges associated with invasive ventilation include ventilator dyssynchrony, air trapping, and dynamic hyperinflation. Careful monitoring and adjustment of ventilatory support parameters helps to optimize the patient-ventilator interaction and minimizes the risk of associated morbidity. Extracorporeal life support is an emerging treatment for refractory hypercapnic respiratory failure associated with obstructive lung disease.

Acute Respiratory Failure

Acute respiratory failure accounts for 25–40 % of ICU admissions and carries a mortality rate of 30 % or more. In this chapter, we classify acute respiratory failure in two main types, based on their primary physiologic abnormality:

Disorders of the airways, where increase of airway resistance to gas flow determines pharmacologic treatment and ventilatory strategies. These disorders are mainly asthma and chronic obstructive pulmonary disease.

Disorders of the alveoli, where a decrease of lung compliance mandates the use of higher ventilatory pressures that can recruit but also damage the lung. These disorders include the acute respiratory distress syndrome, pneumonia, acute cardiogenic pulmonary edema, and influenza.

Additional types of acute respiratory failure are described elsewhere in this book: disorders that result from neuromuscular disease in Chap. 10.1007/978-3-319-19668-8_19 and pulmonary disorders of the circulation, including pulmonary thromboembolism, in Chap. 10.1007/978-3-319-19668-8_27. Finally, we provide a section on weaning from mechanical ventilation, which includes the pathophysiology of the ventilatory load imposed by the prolonged acute respiratory failure, the possible ways to support the weakened respiratory system, and the current process of screening and testing for readiness to remove the ventilator.

Asthma: Hospitalization Trends and Predictors of In-Hospital Mortality and Hospitalization Costs in the USA (2001-2010)

BACKGROUND

In the last decade, the proportion of people with asthma in the USA grew by nearly 15%, with 479,300 hospitalizations and 1.9 million emergency department visits in 2009 alone. The primary objective of our study was to evaluate in-hospital outcomes in patients admitted with asthma exacerbation in terms of mortality, length of stay (LOS) and hospitalization costs.

METHODS

We queried the HCUP's Nationwide Inpatient Sample (NIS) between 2001 and 2010 using the ICD9-CM diagnosis code 493 for asthma (n = 760,418 patients). The NIS represents 20% of all hospitals in the USA. Multivariate logistic regression analysis was used to evaluate predictors of in-hospital mortality. LOS and hospitalization costs were also analyzed.

RESULTS

The overall LOS was 3.9 days and as high as 8.3 days in patients requiring mechanical ventilation. LOS has decreased in recent years, though it continues to be higher than in 2001. The hospitalization cost increased steadily over the study period. The overall in-hospital mortality was 1% and as high as 9.8% in patients requiring mechanical ventilation. Multivariate predictors of longer LOS, higher hospitalization costs and in-hospital mortality included increasing age and hospitalizations during the winter months. Private insurance was predictive of lower hospitalization costs and LOS as well as lower in-hospital mortality.

CONCLUSION

Asthma continues to account for significant in-hospital mortality and resource utilization, especially in mechanically ventilated patients. Age, admissions during winter months and the type of insurance are independent predictors of in-hospital outcomes.

Characteristics and prognosis of near-fatal asthma exacerbations

BACKGROUND

Asthma remains a major public health concern because of its high prevalence and the costs it generates. Near-fatal asthma (NFA) episodes represent the most severe forms of the disease after fatal asthma with significant variations in their incidence between different populations.

OBJECTIVE

To analyze the episodes of NFA over a period of 11 years in the hospital.

METHODS

The authors retrospectively reviewed all admissions due to asthma exacerbation in our hospital between 2000 and 2010 for patients over 18 years of age.

RESULTS

The study included 400 NFA episodes of 285 patients (74% women; mean age 66 years). Of these patients, 228 (80%) had a single episode of NFA and 57 had more than 1 episode during the study period. The authors observed no clear upward or downward trend during the study period. Readmitted patients had more comorbidities, poorer lung function, more severe forms of asthma and more admissions in the year before the index admission. There was a mortality rate of 3.1%. More than 20% of patients were not given controller treatment and more than 40% of patients were not treated with inhaled corticosteroids (ICS).

CONCLUSIONS

NFA episodes are still prevalent in the population of patients with asthma. Reasons for this could be related to improper management in the stable phase, as suggested by the low rate of patients treated with ICS. It also seems necessary to optimize patient management during hospitalization because stays appear prolonged in comparison with studies in other countries.

Mechanical ventilation for severe asthma

Acute exacerbations of asthma can lead to respiratory failure requiring ventilatory assistance. Noninvasive ventilation may prevent the need for endotracheal intubation in selected patients. For patients who are intubated and undergo mechanical ventilation, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia was first proposed 30 years ago and has become the preferred approach. Excessive pulmonary hyperinflation is a major cause of hypotension and barotrauma. An appreciation of the key determinants of hyperinflation is essential to rational ventilator management. Standard therapy for patients with asthma undergoing mechanical ventilation consists of inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation. Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support have also been advocated for patients with fulminant asthma but are rarely necessary. Immediate mortality for patients who are mechanically ventilated for acute severe asthma is very low and is often associated with out-of-hospital cardiorespiratory arrest before intubation. However, patients who have been intubated for severe asthma are at increased risk for death from subsequent exacerbations and must be managed accordingly in the outpatient setting.

Emergency endotracheal intubation-related adverse events in bronchial asthma exacerbation: can anesthesiologists attenuate the risk?

PURPOSE

Airway management in severe bronchial asthma exacerbation (BAE) carries very high risk and should be performed by experienced providers. However, no objective data are available on the association between the laryngoscopist's specialty and endotracheal intubation (ETI)-related adverse events in patients with severe bronchial asthma. In this paper, we compare emergency ETI-related adverse events in patients with severe BAE between anesthesiologists and other specialists.

METHODS

This historical cohort study was conducted at a Japanese teaching hospital. We analyzed all BAE patients who underwent ETI in our emergency department from January 2002 to January 2014. Primary exposure was the specialty of the first laryngoscopist (anesthesiologist vs. other specialist). The primary outcome measure was the occurrence of an ETI-related adverse event, including severe bronchospasm after laryngoscopy, hypoxemia, regurgitation, unrecognized esophageal intubation, and ventricular tachycardia.

RESULTS

Of 39 patients, 21 (53.8 %) were intubated by an anesthesiologist and 18 (46.2 %) by other specialists. Crude analysis revealed that ETI performed by an anesthesiologist was significantly associated with attenuated risk of ETI-related adverse events [odds ratio (OR) 0.090, 95 % confidence interval (CI) 0.020-0.41, p = 0.001]. The benefit of attenuated risk remained significant after adjusting for potential confounders, including Glasgow Coma Score, age, and use of a neuromuscular blocking agent (OR 0.058, 95 % CI 0.010-0.35, p = 0.0020).

CONCLUSIONS

Anesthesiologist as first exposure was independently associated with attenuated risk of ETI-related adverse events in patients with severe BAE. The skill and knowledge of anesthesiologists should be applied to high-risk airway management whenever possible.

Relationship between intubation rate and continuous positive airway pressure therapy in the prehospital setting

BACKGROUND

To determine whether the prehospital use of continuous positive airway pressure (CPAP) therapy is associated with a reduced rate of endotracheal intubation in patients with an acute respiratory disorder brought to the emergency department (ED).

METHODS

We reviewed medical records of patients with acute respiratory distress who had been treated with CPAP in the Mobile Intensive Care Unit (MICU) from January 2010 to December 2011. These records were compared with those of patients who received standardized care without CPAP in the MICU from January 2004 to December 2004. Categorical variables were summarized as frequencies and compared between groups using Fisher's exact test or the Chi-square test. Continuous variables were summarized as medians (interquartile range), and comparison between the groups was made using Wilcoxon's rank-sum test. The relationship between CPAP and intubation rate was determined using multivariable logistic regression analysis of propensity scores. The results were presented as odds ratio (OR), 95% confidence interval (CI), and P value for test effect. The adequacy of the model was calibrated using Hosmer and Lemeshow's goodness-of-fit test. P<0.05 was considered statistically significant.

RESULTS

The records of 785 patients were reviewed. Of the 215 patients treated with CPAP in the MICU, 13% were intubated after admission. In contrast, of the 570 patients who did not receive CPAP, 28% were intubated after ED admission. Unadjusted logistic regression analysis showed that patients who had been treated with CPAP were less likely to be intubated than those without CPAP treatment (OR=0.37, 95%CI, 0.24-0.57, P<0.0001). With propensity scores adjusted, multivariate logistic regression analysis showed that CPAP treatment was associated with a 62% reduction of intubation (OR=0.384, 95%CI, 0.25-0.60, P<0.0001).

CONCLUSIONS

In patients with acute respiratory disorder, there was a relationship between CPAP therapy and the decreased intubation rate. CPAP therapy was feasible in prehospital management of patients with respiratory distress.

Safety and effectiveness of continuous aerosolized albuterol in the non-intensive care setting

OBJECTIVE

To describe the design features, utilization, and outcomes of a protocol treating children with status asthmaticus with continuous albuterol in the inpatient setting.

METHODS

We performed a retrospective cohort analysis of children ages 2 to 18 treated in the non-intensive care, inpatient setting on a standardized treatment protocol for status asthmaticus from July 2011 to June 2013. We assessed characteristics associated with continuous albuterol therapy and, for those treated, duration of therapy and the proportion who clinically deteriorated (ICU transfer or progression to enhanced respiratory support) or who were identified as having hypokalemia or an arrhythmia. Using multivariable logistic regression, we determined which factors were associated with clinical deterioration or prolonged (>24 hours) continuous albuterol.

RESULTS

Of 3003 children meeting study criteria, 1298 (43%) received continuous albuterol. Older age, black race, lower initial oxygen saturation, and higher initial age-standardized heart rate and respiratory rate were associated with initiation of continuous albuterol therapy (P < .001 for all). Median duration of therapy was 14.4 hours (interquartile range, 7.7, 24.6); 340 children (26%) experienced prolonged therapy. Seventy children (5%) experienced clinical deterioration, and 33 children (3%) had identified hypokalemia or arrhythmia. Comorbid pneumonia and emergency department administration of intravenous magnesium or subcutaneous terbutaline were associated with prolonged therapy and clinical deterioration.

CONCLUSIONS

With appropriate support structures and care processes, continuous albuterol can be delivered effectively in the non-ICU, inpatient setting with low rates of adverse outcomes. Certain initial clinical characteristics may help identify patients needing more intensive therapy.

Utilization of mechanical ventilation for asthma exacerbations: analysis of a national database

BACKGROUND

The current frequency of noninvasive (NIV) and invasive mechanical ventilation use in asthma exacerbations (AEs) and the relationship to outcomes are unknown.

METHODS

We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample to identify patients discharged with a principal diagnosis of AE. For each discharge, we determined whether NIV or invasive mechanical ventilation was initiated during the first 2 hospital days. Using multivariate logistic regression to adjust for potential confounders, we determined whether use of mechanical ventilation and in-hospital mortality changed between 2000 and 2008.

RESULTS

The number of AEs increased by 15.8% from 2000 to 2008. The proportion of admissions for which invasive mechanical ventilation was used during the first 2 days decreased from 1.4% in 2000 to 0.73% in 2008, whereas NIV use increased from 0.34% to 1.9%. The adjusted mortality from AEs requiring NIV or invasive mechanical ventilation was unchanged from 2000 to 2008. The hospital stay was also unchanged.

CONCLUSIONS

There was a substantial increase in the use of mechanical ventilation, accompanied by a shift from invasive mechanical ventilation to NIV. Although we could not determine the clinical reasons for this increase, hospital stay and mortality were unchanged. A randomized trial is needed to determine whether NIV can improve outcomes in AEs before widespread adoption makes it impossible to conduct such a trial.

Risk factors, management and outcomes of patients admitted with near fatal asthma to a tertiary care hospital in Riyadh

RATIONALE:

Near-fatal asthma (NFA) has not been well studied in Saudi Arabia. We evaluated NFA risk factors in asthmatics admitted to a tertiary-care hospital and described NFA management and outcomes.

MATERIALS AND METHODS:

This was a retrospective study of NFA patients admitted to an ICU in Riyadh (2006-2010). NFA was defined as a severe asthma attack requiring intubation. To evaluate NFA risk factors, randomly selected patients admitted to the ward for asthma exacerbation were used as controls. Collected data included demographics, information on prior asthma control and various NFA treatments and outcomes.

RESULTS:

Thirty NFA cases were admitted to the ICU in the five-year period. Compared to controls (N = 120), NFA patients were younger (37.5 ± 19.9 vs. 50.3 ± 23.1 years, P = 0.004) and predominantly males (70.0% vs. 41.7%, P = 0.005) and used less inhaled steroids/long-acting ß2-agonists combination (13.6% vs. 38.7% P = 0.024. Most (73.3%) NFA cases presented in the cool months (October-March). On multivariate analysis, age (odds ratio [OR] 0.96; 95% confidence interval [CI], 0.92-0.99, P = 0.015) and the number of ED visits in the preceding year (OR, 1.25; 95% CI, 1.00-1.55) were associated with NFA. Rescue NFA management included ketamine (50%) and theophylline (19%) infusions. NFA outcomes included: neuromyopathy (23%), mechanical ventilation duration = 6.4 ± 4.7 days, tracheostomy (13%) and mortality (0%). Neuromuscular blockade duration was associated with neuromyopathy (OR, 3.16 per one day increment; 95% CI, 1.27-7.83).

CONCLUSIONS:

In our study, NFA risk factors were younger age and higher number of ED visits. NFA had significant morbidity. Reducing neuromuscular blockade duration during ventilator management may decrease neuromyopathy risk.

Early administration of terbutaline in severe pediatric asthma may reduce incidence of acute respiratory failure

BACKGROUND

Severe pediatric asthma, if not immediately and aggressively treated, may progress to acute respiratory failure requiring mechanical ventilation in the pediatric intensive care unit (PICU). Intravenous (IV) terbutaline, a β2 agonist, is dispensed when the initial treatment does not improve the clinical condition.

OBJECTIVE

To investigate the influence of early initiation of IV terbutaline on the incidence of acute respiratory failure requiring mechanical ventilation in severe pediatric asthma.

METHODS

A retrospective chart review was conducted of 120 subjects (35 patients from an outside hospital emergency department [ED] with late start of terbutaline and 85 patients from the authors' hospital ED with early initiation of IV terbutaline) admitted to the PICU with severe asthma treated with continuous IV terbutaline. Responses to terbutaline treatment and outcomes were evaluated.

RESULTS

Patients transported from outlying hospital EDs had shorter pre-PICU mean durations of IV terbutaline than those transferred from the authors' ED (0.69 ± 1.38 and 2.91 ± 2.47 hours, respectively, P = .001). Twenty-one of 35 patients (60%) from outlying EDs required mechanical ventilation compared with 14 of 85 patients (16%) from the authors' ED (P = .001). Durations of pre-PICU terbutaline infusion for patients requiring mechanical ventilation were significantly shorter than those with no such requirement (P = .015).

CONCLUSION

The results of the present study, conducted in the largest number of subjects to date, suggest that early administration of continuous terbutaline in the ED may decrease acute respiratory failure and the need for mechanical respiratory (invasive and noninvasive) support in severe pediatric asthma.