Acute asthma

Management of the Difficult Airway

ABSTRACT

Airway management is a fundamental component of care during resuscitation of critically ill and injured children. In addition to predicted anatomic and physiologic differences in children compared with adults, certain conditions can predict potential difficulty during pediatric airway management. This review presents approaches to identifying pediatric patients in whom airway management is more likely to be difficult, and discusses strategies to address such challenges. These strategies include optimization of effective bag-mask ventilation, alternative approaches to laryngoscopy, use of adjunct airway devices, modifications to rapid sequence intubation, and performance of surgical airways in children. The importance of considering systems of care in preparing for potentially difficult pediatric airways is also discussed.

Extracorporeal and advanced therapies for progressive refractory near-fatal acute severe asthma in children

Asthma is the most common chronic illness and is one of the most common medical emergencies in children. Progressive refractory near-fatal asthma requiring intubation and mechanical ventilation can lead to death. Extracorporeal membrane oxygenation (ECMO) can provide adequate gas exchange during acute respiratory failure although data on outcomes in children requiring ECMO support for status asthmaticus is sparse with one study reporting survival rates of nearly 85% with asthma being one of the best outcome subsets for patients with refractory respiratory failure requiring ECMO support. We describe the current literature on the use of ECMO and other advanced extracorporeal therapies available for children with acute severe asthma. We also review other advanced invasive and noninvasive therapies in acute severe asthma both before and while on ECMO support.

Inflammatory and Comorbid Features of Children Admitted to a PICU for Status Asthmaticus

OBJECTIVES

To determine risk factors associated with admission to a PICU with or without endotracheal intubation for an asthma exacerbation. We hypothesized that children with critical and near-fatal asthma would have distinguishing clinical features but varying degrees of asthma severity and measures of type 2 inflammation.

DESIGN

Retrospective analysis of prospectively collected data of children with asthma recruited into outpatient asthma clinical research studies at Emory University between 2004 and 2015.

SETTING

Large, free-standing academic quaternary care children's hospital in Atlanta, GA.

PATIENTS

Children 6-18 years old with physician-diagnosed and confirmed asthma.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 579 children were analyzed with 170 children (29.4%) being admitted to the PICU for an asthma exacerbation in their lifetime. Of these 170 children with a history of critical asthma, 24.1% were classified as having mild-to-moderate asthma, and 83 of 170 children (48.8%) had been intubated and experienced near-fatal asthma. Multiple logistic regression was used to identify risk factors associated with increased odds of PICU admission with or without endotracheal intubation. Hospitalization within the prior 12 months of survey (odds ratio, 8.19; 95% CI, 4.83-13.89), a history of pneumonia (odds ratio, 2.56; 95% CI, 1.52-4.29), having a designation of increased chronic asthma severity on high-dose inhaled corticosteroids (odds ratio, 2.76; 95% CI, 1.62-4.70), having a father with asthma (odds ratio, 2.15; 95% CI, 1.23-3.76), living in a region with a higher burden of poverty (odds ratio, 1.28; 95% CI, 1.02-1.61), and being of black race (odds ratio, 2.01; 95% CI, 1.05-3.84) were all associated with increased odds of PICU admission with or without intubation.

CONCLUSIONS

Our findings suggest that there are factors associated with critical and near-fatal asthma, distinct from the chronic asthma severity designations, that should be the focus of future investigation.

An Unusual Complication With the Administration of a Volatile Anesthetic Agent for Status Asthmaticus in the Pediatric Intensive Care Unit: Case Report and Review of the Literature

In severe cases of status asthmaticus, when conventional therapies fail, volatile anesthetic agents remain a therapeutic option. When delivered outside of the operating room setting, specialized delivery techniques are needed to ensure the safe and effective use of volatile anesthetic agents. We present a 16-year-old adolescent with status asthmaticus who required the therapeutic administration of the volatile anesthetic agent, sevoflurane, in the pediatric intensive care unit (PICU). Although initially effective in reducing bronchospasm, progressive hypercarbia developed due to defective functioning of the carbon dioxide absorber of the anesthesia machine. This failure occurred as the soda lime compartment filled with water accumulated from circuit humidification and continuous albuterol therapy. The role of volatile anesthetic agents in the treatment of status asthmaticus in the PICU is discussed, options for delivery outside of the operating room presented, and potential problems with delivery reviewed.

Severe angina pectoris in asthma attack: a case report

Asthma is a chronic inflammatory disorder of the airways related to the obstruction of reversible airflow. Asthma presents as recurrent attacks of cough and dyspnea. Poor control causes recurrent admissions to the ICU, and mortality is related to poor drug compliance and follow-up. Angina pectoris is a syndrome of recurrent chest discomfort related to myocardial ischemia. The presence of these two disorders rarely has been reported. We reported a 12-year-old boy who was referred with exacerbation of asthma and developed angina pectoris during hospitalization. He had labored breathing and diffuse wheezing. During treatment of the asthma, the patient developed severe chest pain due to shunt formation and coronary hypoxia, caused by the sole administration of ventolin, since oxygen had been disconnected. After receiving appropriate therapy, both his asthma and angina recovered, and, to date, he has not experienced angina pectoris again.

Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit

OBJECTIVE

The goal of this report is to review available modalities for assessing and managing acute asthma exacerbations in pediatric patients, including some that are not included in current expert panel guidelines. While it is not our purpose to provide a comprehensive review of the National Asthma Education and Prevention Program (NAEPP) guidelines, we review NAEPP-recommended treatments to provide the full range of treatments available for managing exacerbations with an emphasis on the continuum of care between the ER and ICU.

DATA SOURCES

We searched PubMed using the following search terms in different combinations: asthma, children, pediatric, exacerbation, epidemiology, pathophysiology, guidelines, treatment, management, oxygen, albuterol, β2-agonist, anticholinergic, theophylline, corticosteroid, magnesium, heliox, BiPAP, ventilation, mechanical ventilation, non-invasive mechanical ventilation and respiratory failure. We attempted to weigh the evidence using the hierarchy in which meta-analyses of randomized controlled trials (RCTs) provide the strongest evidence, followed by individual RCTs, followed by observational studies. We also reviewed the NAEPP and Global Initiative for Asthma expert panel guidelines.

RESULTS AND CONCLUSIONS

Asthma is the most common chronic disease of childhood, and acute exacerbations are a significant burden to patients and to public health. Optimal assessment and management of exacerbations, including appropriate escalation of interventions, are essential to minimize morbidity and prevent mortality. While inhaled albuterol and systemic corticosteroids are the mainstay of exacerbation management, escalation may include interventions discussed in this review.

Outcomes of invasive mechanical ventilation in children and adolescents hospitalized due to status asthmaticus in United States: a population based study

OBJECTIVE

Current national estimates of and outcomes of Invasive Mechanical Ventilation (MV) in status asthmaticus (SA) are unclear. The objective of this study is to estimate the incidence and outcomes of MV in hospitalized SA children and adolescents.

METHODS

We used the Nationwide Inpatient Sample (NIS, 2009-2010), the largest all-payer hospital discharge database in United States. All hospitalizations (age ≤21 years) with a primary diagnosis of SA were selected. MV was identified using ICD-9-CM procedure codes. Multivariable regression analyses were used to examine the association between MV and outcomes (Length of Stay (LOS) and Hospital Charges (HC)).

RESULTS

Over the study period, of the 250 718 SA hospitalizations, MV was needed for <96 h in 0.37% hospitalizations and 0.18% had MV for ≥96 h. Complications occurred in 12.4% (30 991) of all hospitalizations with pneumonia (10.8%) being the most common. A total of 65 patients died in hospitals (the overall in-hospital mortality [IHM] rate was 0.03%). About 55 of these deaths occurred among those who had MV (4% IHM rate for those receiving MV). The mean LOS and hospital HC included without MV (2.1 d, $11 921) MV < 96 h (4.8 d, $52 201); MV > 96 h (15.6 d, $200 336). After adjustment for patient/hospital level factors, the need for MV was associated with significantly higher LOS and HC (p < 0.0001). Those who had MV<96 h (OR = 2.58, 95% CI = 1.77-3.77) or MV ≥ 96 h (OR = 6.23, 95% CI = 3.87-10.03) had higher risk of developing pneumonia.

CONCLUSIONS

Although MV is infrequently needed in children and adolescents hospitalized for SA (0.55% incidence rate), it is associated with higher IHM rate and significant hospital resource utilization.

Development of learning objectives and a validated testing tool for management of pediatric mechanical ventilation*

OBJECTIVES

Graduate medical education is shifting toward an outcome-based paradigm, where physicians are evaluated for competency using well-defined criteria. Our aim was to learning objectives and a testing tool to assess competency in the management of mechanical ventilation for infants, children, and adolescents and to verify that the test was reliable and valid.

DESIGN

Prospective reliability and validity study.

SETTING

Large, university-affiliated academic hospital.

SUBJECTS

Sixty-one total subjects from five different academic centers divided into three groups of varying experience. The groups were second- and third-year pediatric residents (Novice), second- and third-year pediatric critical care fellows (Advanced), and pediatric critical care faculty (Expert).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ten learning objectives considered important for the management of pediatric mechanical ventilation were developed from expert opinion and current evidence. Based on these objectives, a 35-question multiple choice, knowledge- and case-based test was created. Content validity was achieved by consensus of three experts in pediatric critical care medicine evaluating whether the questions reflected the learning objectives and the responses were consistent with current practice and evidence-based medicine. The test was then administered to the three groups to establish construct validity. The "Novice" group scored a mean of 34.6% (95% CI, 28-41%), the "Advanced" group a mean of 59.4% (95% CI, 53-65%), and the "Expert" group a mean of 74.8% (95% CI, 69-80%), with p less than 0.01 for all comparisons. As determined by Hoyt's analysis, the reliability coefficient was 0.89, reflecting excellent reliability.

CONCLUSIONS

This is the first description of specific learning objectives for management of pediatric mechanical ventilation and the first validated and reliable testing tool for assessing knowledge. This tool could be used by fellowship programs to assess fellow competency and identify knowledge gaps in this area prior to completion of training. Further work must be done to determine the criteria for determination of competency.

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.

Fatal and near-fatal asthma in children: the critical care perspective

OBJECTIVE

To characterize the clinical course, therapies, and outcomes of children with fatal and near-fatal asthma admitted to pediatric intensive care units (PICUs).

STUDY DESIGN

This was a retrospective chart abstraction across the 8 tertiary care PICUs of the Collaborative Pediatric Critical Care Research Network (CPCCRN). Inclusion criteria were children (aged 1-18 years) admitted between 2005 and 2009 (inclusive) for asthma who received ventilation (near-fatal) or died (fatal). Data collected included medications, ventilator strategies, concomitant therapies, demographic information, and risk variables.

RESULTS

Of the 261 eligible children, 33 (13%) had no previous history of asthma, 218 (84%) survived with no known complications, and 32 (12%) had complications. Eleven (4%) died, 10 of whom had experienced cardiac arrest before admission. Patients intubated outside the PICU had a shorter duration of ventilation (median, 25 hours vs 84 hours; P < .001). African-Americans were disproportionately represented among the intubated children and had a shorter duration of intubation. Barotrauma occurred in 15 children (6%) before admission. Pharmacologic therapy was highly variable, with similar outcomes.

CONCLUSION

Of the children ventilated in the CPCCRN PICUs, 96% survived to hospital discharge. Most of the children who died experienced cardiac arrest before admission. Intubation outside the PICU was correlated with shorter duration of ventilation. Complications of barotrauma and neuromyopathy were uncommon. Practice patterns varied widely among the CPCCRN sites.

Current management of status asthmaticus in the pediatric ICU

Status asthmaticus (SA) in the pediatric ICU (PICU) can progress to a life-threatening emergency. The goal of management is to improve hypoxemia, improve bronchoconstriction, and decrease airway edema through the administration of continuous nebulized beta2 adrenergic agonist with intermittent anticholinergics, corticosteroids, and oxygen. Adjunctive therapies, such as magnesium, methylxanthines, intravenous beta-agonists, heliox, and noninvasive ventilation should be considered in the child who fails to respond to initial therapies. The restoration of adequate pulmonary functions, resolution of airway obstruction, and avoidance of mechanical ventilation should guide management. This article reviews the pathophysiology, assessment, and management of the child who has SA in the PICU to provide the critical care nurse with current information to facilitate optimal care.

Hypercapnia: what is the limit in paediatric patients? A case of near-fatal asthma successfully treated by multipharmacological approach

We describe a case of prolonged severe hypercapnia with respiratory acidosis occurring during an episode of near-fatal asthma in an 8-year-old boy, followed by complete recovery. After admission to the intensive care unit, despite treatment with maximal conventional bronchodilatative therapy, the clinical picture deteriorated with evident signs of respiratory muscle fatigue. The child was sedated, intubated and mechanically ventilated. Magnesium sulphate, ketamine and sevoflurane were gradually introduced together with deep sedation, curarization and continuous bronchodilatative therapy. Ten hours after admission, arterial pCO2 reached 39 kPa (293 mmHg), pH was 6.77 and pO2 8.6 kPa (65 mmHg). Chest radiograph showed severe neck subcutaneous emphysema, with signs of mediastinal emphysema. No episode of haemodynamic instability was seen despite severe prolonged hypercapnia lasting more than 14 h. Oxygenation was maintained and successful recovery followed without neurological or cardiovascular sequelae. This case shows the cardiovascular and neurological tolerance of a prolonged period of supercarbia in a paediatric patient. The most important lesson to be learned is the extreme importance of maintaining adequate tissue perfusion and oxygenation during an asthma attack. The second lesson is that when conventional bronchodilators fail, the intensivist may resort to the use of drugs such as ketamine, magnesium sulphate and inhalation anaesthesia. In this context deep sedation and curarization are important not only to improve oxygenation, but also to reduce cerebral metabolic requirements.