Review article: management of acute severe and near-fatal 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.

Epinephrine (adrenaline) compared to selective beta-2-agonist in adults or children with acute asthma: a systematic review and meta-analysis

BACKGROUND

International asthma guidelines recommend against epinephrine (adrenaline) administration in acute asthma unless associated with anaphylaxis or angio-oedema. However, administration of intramuscular epinephrine in addition to nebulised selective β₂-agonist is recommended for acute severe or life-threatening asthma in many prehospital guidelines. We conducted a systematic review to determine the efficacy of epinephrine in comparison to selective β₂-agonist in acute asthma.

METHODS

We included peer-reviewed publications of randomised controlled trials (RCTs) that enrolled children or adults in any healthcare setting and compared epinephrine by any route to selective β₂-agonist by any route for an acute asthma exacerbation. The primary outcome was treatment failure, including hospitalisation, need for intubation or death.

RESULTS

Thirty-eight of 1140 studies were included. Overall quality of evidence was low. Seventeen studies contributed data on 1299 participants to the meta-analysis. There was significant statistical heterogeneity, I²=56%. The pooled Peto's OR for treatment failure with epinephrine versus selective β₂-agonist was 0.99 (0.75 to 1.32), p=0.95. There was strong evidence that recruitment age group was associated with different estimates of the odds of treatment failure; with studies recruiting adults-only having lower odds of treatment failure with epinephrine. It was not possible to determine whether epinephrine in addition to selective β₂-agonist improved outcomes.

CONCLUSION

The low-quality evidence available suggests that epinephrine and selective β₂-agonists have similar efficacy in acute asthma. There is a need for high-quality double-blind RCTs to determine whether addition of intramuscular epinephrine to inhaled or nebulised selective β₂-agonist improves outcome.

PROSPERO REGISTRATION NUMBER

CRD42017079472.

Extracorporeal membrane oxygenation for life-threatening asthma refractory to mechanical ventilation: analysis of the Extracorporeal Life Support Organization registry

Background

The use of extracorporeal membrane oxygenation (ECMO) in cases of near-fatal asthma (NFA) has increased, but the benefits and potential complications of this therapy have yet to be fully investigated.

Methods

Cases were extracted from the Extracorporeal Life Support Organization Registry between March 1992 and March 2016. All patients with a diagnosis of asthma (according to the International Classification of Diseases 9th edition), who also received ECMO, were extracted. Exclusion criteria included patients who underwent multiple courses of ECMO; those who received ECMO for cardiopulmonary resuscitation or cardiac dysfunction; and those with another primary diagnosis, such as sepsis. We analyzed survival to hospital discharge, complications, and clinical factors associated with in-hospital mortality, in patients with severe life-threatening NFA requiring ECMO support.

Results

In total 272 patients were included. The mean time spent on ECMO was 176.4 hours. Ventilator settings, including rate, fraction of inspired oxygen (FiO₂), peak inspiratory pressure (PIP), and mean airway pressure, significantly improved after ECMO initiation (rate (breaths/min), 19.0 vs. 11.3, p < 0.001; FiO₂ (%), 81.2 vs. 48.8, p < 0.001; PIP (cmH₂O), 38.2 vs. 25.0, p < 0.001; mean airway pressure (cmH₂O): 21.4 vs. 14.2, p < 0.001). In particular, driving pressure was significantly decreased after ECMO support (29.5 vs. 16.8 cmH₂O, p < 0.001). The weaning success rate was 86.7%, and the rate of survival to hospital discharge was 83.5%. The total complication rate was 65.1%, with hemorrhagic complications being the most common (28.3%). Other complications included renal (26.8%), cardiovascular (26.1%), mechanical (24.6%), metabolic (22.4%), infection (16.5%), neurologic (4.8%), and limb ischemia (2.6%). Of the hemorrhagic complications, cannulation site hemorrhage was the most common (13.6%). Using multivariate logistic regression analysis, it was found that hemorrhage was associated with increased in-hospital mortality (odds ratio, 2.97; 95% confidence interval, 1.07–8.24; p = 0.036). Hemorrhage-induced death occurred in four patients (1.5%). The most common reason for death was organ failure (37.8%).

Conclusions

ECMO can provide adequate gas exchange and prevent lung injury induced by mechanical ventilation, and may be an effective bridging strategy to avoid aggressive ventilation in refractory NFA. However, careful management is required to avoid complications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1886-8) contains supplementary material, which is available to authorized users.

Acetylcholinesterase Inhibitors and Drugs Acting on Muscarinic Receptors- Potential Crosstalk of Cholinergic Mechanisms During Pharmacological Treatment

BACKGROUND

Pharmaceuticals with targets in the cholinergic transmission have been used for decades and are still fundamental treatments in many diseases and conditions today. Both the transmission and the effects of the somatomotoric and the parasympathetic nervous systems may be targeted by such treatments. Irrespective of the knowledge that the effects of neuronal signalling in the nervous systems may include a number of different receptor subtypes of both the nicotinic and the muscarinic receptors, this complexity is generally overlooked when assessing the mechanisms of action of pharmaceuticals.

METHODS

We have search of bibliographic databases for peer-reviewed research literature focused on the cholinergic system. Also, we have taken advantage of our expertise in this field to deduce the conclusions of this study.

RESULTS

Presently, the life cycle of acetylcholine, muscarinic receptors and their effects are reviewed in the major organ systems of the body. Neuronal and non-neuronal sources of acetylcholine are elucidated. Examples of pharmaceuticals, in particular cholinesterase inhibitors, affecting these systems are discussed. The review focuses on salivary glands, the respiratory tract and the lower urinary tract, since the complexity of the interplay of different muscarinic receptor subtypes is of significance for physiological, pharmacological and toxicological effects in these organs.

CONCLUSION

Most pharmaceuticals targeting muscarinic receptors are employed at such large doses that no selectivity can be expected. However, some differences in the adverse effect profile of muscarinic antagonists may still be explained by the variation of expression of muscarinic receptor subtypes in different organs. However, a complex pattern of interactions between muscarinic receptor subtypes occurs and needs to be considered when searching for selective pharmaceuticals. In the development of new entities for the treatment of for instance pesticide intoxication, the muscarinic receptor selectivity needs to be considered. Reactivators generally have a muscarinic M2 receptor acting profile. Such a blockade may engrave the situation since it may enlarge the effect of the muscarinic M3 receptor effect. This may explain why respiratory arrest is the major cause for deaths by esterase blocking.

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.

[Cerebral hemorrhage in a mechanically ventilated asthmatic child: multifactorial mechanisms]

We report the case of a 7-year-old boy with acute status asthmaticus requiring mechanic ventilation in the pediatric intensive care unit. He developed a brain hemorrhage during the course of his illness. We discuss the mechanisms that may have precipitated this neurological complication.

Acute lung failure

Lung failure is the most common organ failure seen in the intensive care unit. The pathogenesis of acute respiratory failure (ARF) can be classified as (1) neuromuscular in origin, (2) secondary to acute and chronic obstructive airway diseases, (3) alveolar processes such as cardiogenic and noncardiogenic pulmonary edema and pneumonia, and (4) vascular diseases such as acute or chronic pulmonary embolism. This article reviews the more common causes of ARF from each group, including the pathological mechanisms and the principles of critical care management, focusing on the supportive, specific, and adjunctive therapies for each condition.

[Severe acute asthma: isoflurane administration via AnaConDa™, is it safe?]

Standard treatments against severe acute asthma can be insufficient and need salvation treatments, such as isoflurane delivery. These treatments have not been much assessed and could lead to unrecognized side-effects. We report the case of a young man who suffered from intracranial hypertension associated with severe hypercapnia during the delivery of isoflurane via the system AnaConDa™ or Anaesthetic Conserving Device™ (ACD) (Sedama Medical). The rising of PaCO(2) appears to be linked to an ACD-dependent increase in the dead space.