Treatment of critical status asthmaticus in children

Ketamine in Chronic Pain: A Review

Ketamine has been used in the treatment of several pain syndromes, particularly those with a relevant neuropathic component. Sub-anesthetic doses of ketamine produce a potent analgesic effect, due to its inhibition of N-methyl-D-aspartate receptors and enhancement of descending inhibitory pathways. Its short-term analgesic effect is well-documented perioperatively, with an associated reduction in postoperative chronic pain and opioid consumption. Despite some evidence regarding its long-term benefits, the number of clinical studies is still limited. In addition to its analgesic effects, ketamine also possesses an anti-depressive action, which might be useful in the treatment of chronic pain patients. Several side effects have been described, the psychomimetic ones being the most relevant due to their impact on treatment adhesion. At present, co-administration of ketamine and benzodiazepines or α2-agonists facilitates its clinical application. Despite current evidence and increasing use, further investigation is still needed regarding its long-term safety profile and clearer risk-benefit analysis.

Severe acute asthma exacerbation in children: a stepwise approach for escalating therapy in a pediatric intensive care unit

OBJECTIVES

An increasing prevalence of pediatric asthma has led to increasing burdens of critical illness in children with severe acute asthma exacerbations, often leading to respiratory distress, progressive hypoxia, and respiratory failure. We review the definitions, epidemiology, pathophysiology, and clinical manifestations of severe acute asthma, with a view to developing an evidence-based, stepwise approach for escalating therapy in these patients.

METHODS

Subject headings related to asthma, status asthmaticus, critical asthma, and drug therapy were used in a MEDLINE search (1980-2012), supplemented by a manual search of personal files, references cited in the reviewed articles, and treatment algorithms developed within Le Bonheur Children's Hospital.

RESULTS

Patients with asthma require continuous monitoring of their cardiorespiratory status via noninvasive or invasive devices, with serial clinical examinations, objective scoring of asthma severity (using an objective pediatric asthma score), and appropriate diagnostic tests. All patients are treated with β-agonists, ipratropium, and steroids (intravenous preferable over oral preparations). Patients with worsening clinical status should be progressively treated with continuous β-agonists, intravenous magnesium, helium-oxygen mixtures, intravenous terbutaline and/or aminophylline, coupled with high-flow oxygen and non-invasive ventilation to limit the work of breathing, hypoxemia, and possibly hypercarbia. Sedation with low-dose ketamine (with or without benzodiazepines) infusions may allow better toleration of non-invasive ventilation and may also prepare the patient for tracheal intubation and mechanical ventilation, if indicated by a worsening clinical status.

CONCLUSIONS

Severe asthma can be a devastating illness in children, but most patients can be managed by using serial objective assessments and the stepwise clinical approach outlined herein. Following multidisciplinary education and training, this approach was successfully implemented in a tertiary-care, metropolitan children's hospital.

8-Isoprostane in the exhaled breath condensate of children hospitalized for status asthmaticus

OBJECTIVE

To evaluate the safety and feasibility of exhaled breath condensate (EBC) collection in children recovering from status asthmaticus (SA) in a pediatric intensive care unit (PICU); and to investigate whether 8-isoprostane (8-Iso) could be detected in the EBC of these children and to compare its concentration with that in the EBC collected from healthy children.

DESIGN

Prospective study.

SETTING

Multidisciplinary PICU in a teaching hospital.

PATIENTS

Sixteen consecutive patients (7-18 yrs of age) with SA and 16 age- and sex-matched controls.

INTERVENTIONS

The Wood clinical asthma score and the pulmonary index were used to assess the clinical severity of patients with SA upon admission to the PICU. EBC samples were collected within 24 hrs of admission to the PICU and were analyzed for the concentration of 8-Iso.

MEASUREMENTS AND MAIN RESULTS

Data are presented as mean ± sd values. There were no differences in age (12 ± 3.3 yrs vs.12 ± 2 yrs, p > .05) or sex (n = 10 males and n = 6 females in each group), between SA patients and controls. All patients with SA and the controls completed the EBC collection without complications. There was no statistically significant difference in the pulmonary index (3.2 ± 2.7 vs. 3.1 ± 2.8, p 0.9) post collection of EBC compared with the baseline values. There was a statistically significant correlation between Wood score and pulmonary index at the time of admission to the PICU in children with SA (r = .7, p < .01). The concentration of 8-Iso was significantly higher in the EBC of children with SA compared with controls (14.3 ± 1.8 pg/mL vs. 5.2 ± 0.7 pg/mL, p < .001). The correlation between the concentration 8-Iso and either the pulmonary index or Wood score at the time admission to the PICU was not statistically significant.

CONCLUSIONS

EBC collection is well tolerated by children aged 7-18 yrs who are recovering from SA in a PICU. 8-Iso is elevated in the EBC from children with SA and may provide insight into the biochemical changes of oxidative stress in children in this clinical setting.

Management of acute asthma exacerbations in children

The management of acute asthma exacerbations in children remains controversial and the latest guidelines (Expert Panel Report [EPR]-3 2007 and the Global Initiative of Asthma 2008) leave several questions unanswered. This review summarizes the most up-to-date information on the practical prevention and control of asthma attacks in children, and describes the 20-year experience of a major tertiary asthma clinic with the administration of inhaled corticosteroids in this setting. The following subjects are discussed: the knowledge and skills required by the parents regarding asthma and its treatment, how to prevent or minimize exacerbations in asthmatic children, the drugs used in the treatment of exacerbations and their order of administration, and the steps to follow after discharge from the emergency department or after a severe asthma exacerbation. The efficacy of inhaled corticosteroids in the management of acute asthma exacerbations in children, both at home and in the emergency department, is discussed in detail. The goal of asthma-management programs is to arm parents with the skills and knowledge to prevent, detect and successfully control most exacerbations of asthma in children at home.

Pediatric obesity in acute and critical care

Pediatric obesity has reached epidemic proportions in the United States. Significant obesity-related comorbidities are being noted at earlier ages and often have implications for the acute and critically ill child. This article will review the latest in epidemiologic trends of pediatric obesity and examine how it affects multisystem body organs. The latest data evaluating the specific effects of obesity on acute and critically ill children will be reviewed. Available nonpharmacologic, pharmacologic, and surgical strategies to combat pediatric obesity will be discussed.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Childhood obesity increases duration of therapy during severe asthma exacerbations

OBJECTIVES

Childhood obesity contributes to a wide array of medical conditions, including asthma. There is also increasing evidence in adult patients admitted to the intensive care unit (ICU) that obesity contributes to increased morbidity and to a prolonged length of stay. We hypothesized that obesity is associated with the need for increased duration of therapy in children admitted to the ICU with status asthmaticus.

DESIGN

Retrospective cohort study.

SETTING

A tertiary pediatric ICU in a university-affiliated children's hospital.

PATIENTS

We retrospectively examined data from all children older than 2 yrs admitted to the ICU with status asthmaticus between April 1997 and June 2004. Children were classified as normal weight (<95% weight-for-age percentile) or obese (>95% weight-for-age).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 209 children admitted to the ICU with asthma, 45 (22%) were obese. Compared with children of normal weight, the obese children were older (9.7 +/- 4.4 vs. 8.0 +/- 4.3 yrs, p = .02), more likely to be female (60% vs. 37%, p < .01), and more likely to have been admitted to the ICU previously (40% vs. 20%, p = .01). The obese children also had a statistically significant difference in race (more likely to be Hispanic) and in baseline asthma classification (more likely to have persistent asthma). Despite similar severity of illness at ICU admission, obese children had a significantly longer ICU length of stay (116 +/- 125 hrs vs. 69 +/- 57 hrs, p = .02) and hospital length of stay (9.8 +/- 7.0 vs. 6.5 +/- 3.4 days, p < .01). Obese children also received longer courses of supplemental oxygen, continuous albuterol, and intravenous steroids.

CONCLUSIONS

Childhood obesity significantly affects the health of children with asthma. Obese children with status asthmaticus recovered more slowly from an acute exacerbation, even after adjustment for baseline asthma severity and admission severity of illness.

A modified pulmonary index score with predictive value for pediatric asthma exacerbations

BACKGROUND

Several clinical asthma scores have been derived from combinations of physical findings in pediatric asthmatic patients.

OBJECTIVE

To test the reproducibility and validity of one such score, the Modified Pulmonary Index Score (MPIS), and to evaluate its predictive value in children hospitalized for asthma.

METHODS

In the MPIS, 6 categories are evaluated: oxygen saturation, accessory muscle use, inspiratory to expiratory flow ratio, degree of wheezing, heart rate, and respiratory rate. For each of these 6 measurements or observations, a score of 0 to 3 is assigned. To evaluate the reproducibility of the MPIS, inpatients with status asthmaticus were examined by an attending physician, nurse, and respiratory therapist who were blinded to the other observers' scores. To evaluate the validity of the MPIS as a scale of severity of illness in asthmatic patients, the score at admission was compared with selected outcomes in the same patients.

RESULTS

A total of 30 patients participated in this study (mean +/- SD age, 7.6 +/- 5.5 years). Our finding revealed that the MPIS is highly reproducible with a high degree of interrater reliability across caregiver groups (physician to nurse: r = 0.98; 95% confidence interval [CI], >0.96; physician to respiratory therapist: r = 0.95; 95% CI, >0.92; nurse to respiratory therapist: r = 0.94; 95% CI, >0.90). The admission MPIS positively correlated with intensive care unit admission (P < .001), days of continuous albuterol therapy (P = .002), days of supplemental oxygen (P = .002), and length of hospital stay (P = .004).

CONCLUSIONS

The MPIS is a highly reproducible and valid indicator of severity of illness in children with asthma. To our knowledge, this is the first pediatric clinical asthma score demonstrated to be reproducible across groups of health care professionals who treat pediatric patients with asthma.

Helium-oxygen therapy for pediatric acute severe asthma requiring mechanical ventilation

OBJECTIVE

To illustrate the use of helium-oxygen gas mixtures as therapy for pediatric patients with acute severe asthma requiring conventional mechanical ventilation.

DESIGN

Retrospective review.

SETTING

Tertiary care children's teaching hospital.

PATIENTS

All mechanically ventilated patients with severe asthma admitted to the pediatric intensive care unit from August 1994 to October 2000.

INTERVENTIONS

Within 24 hrs of intubation or admission, patients were stabilized on volume ventilation, bronchodilator therapy, corticosteroids, and antibiotics when indicated. Hypercapnia was permitted while maintaining arterial blood gas pH > or =7.25. A helium-oxygen gas mixture then was begun with helium flow set at 5-7 L/min, and oxygen flow was titrated to maintain desired oxygen saturation. Only sedated, chemically paralyzed patients with adequate pre-helium-oxygen and post-helium-oxygen measurements were statistically analyzed.

MEASUREMENTS AND MAIN RESULTS

Twenty-eight mechanically ventilated patients with severe asthma placed on helium-oxygen gas mixtures were identified who met study entry criteria. Mean patient age was 8.8 yrs (range, 1.1-14.6). Before helium-oxygen therapy began, mean peak inspiratory pressure was 40.5 +/- 4.2 cm H(2)O, mean arterial blood gas pH was 7.26 +/- 0.05, and mean CO(2) partial pressure was 58.2 +/- 8.5 torr. After patients were placed on helium-oxygen therapy, there was a significant decrease in mean peak inspiratory pressure to 35.3 +/- 3.0 cm H(2)O. Mean pH increased significantly to 7.32 +/- 0.06, and mean partial pressure CO(2) decreased significantly to 50.5 +/- 7.4 torr. Initial mean inspired helium was 57 +/- 4% (range, 32-74). Mechanical ventilation days ranged from 1 to 23 days (mean, 5.0). Hospital stay ranged from 4 to 29 days (mean, 10.1), with an average pediatric intensive care unit stay of 6.9 days (range, 2-24). There were two incidences of pneumothorax.

CONCLUSIONS

In the pediatric patient with severe asthma requiring conventional mechanical ventilation, helium-oxygen administration appears to be a safe therapy and may assist in lowering peak inspiratory pressure and improving blood gas pH and partial pressure CO(2).

Magnesium sulfate administered via continuous intravenous infusion in pediatric patients with refractory wheezing

PURPOSE

To evaluate the dosing and safety of intravenous magnesium sulfate administered via continuous infusion for refractory wheezing.

MATERIALS AND METHODS

All patients admitted to the pediatric intensive care unit (PICU) between January 1998 and March 2001 who were prescribed magnesium sulfate via continuous infusion were identified via retrospective chart review. The patient's medical history, demographic data, vital signs, magnesium dosing history, and concurrent medications were recorded.

RESULTS

Forty PICU patients represent our study population. The mean age was 82.6 +/- 64.6 mo; 18 patients were boys.The mean magnesium loading dose (mg/kg) was 29.6 +/- 13.2 with a mean infusion dose (mg/kg/h) of 18.4 +/- 6.5 with a significant difference in dosing noted between patients weighing less than 30 kg and those with a higher weight. The mean magnesium loading dose (mg/kg) in the less than 30 kg group was 35.3 +/- 12.7 compared with 21.9 +/- 9.9 in the higher weight group (P <.05). Mean infusion doses (mg/kg/h) were 21.6 +/- 6 and 14.6 +/- 4.2, respectively (P <.05). There was no significant difference between the mean concentrations (mg/dL) reported between the 2 groups (less than 30 kg group = 3.9 +/- 0.6; higher weight group = 3.6 +/- 0.5). All patients received nebulized albuterol, ipratropium, and intravenous methylprednisolone before magnesium therapy. Aminophylline and ketamine were prescribed to 28 and 4 patients, respectively. No cardiovascular adverse effects were noted during magnesium therapy.

CONCLUSIONS

For the treatment of refractory wheezing, intravenous magnesium sulfate administered via continuous infusion represents a safe mode of drug delivery.

Management of acute pediatric asthma

Pediatric asthma prevalence, morbidity, and severity are increasing. Direct costs associated with providing emergency department and inpatient care account for more than 40% of overall dollars spent for this disease in the United States. Physicians in many health care settings may be required to treat a child in severe respiratory distress caused by acute asthma. This article reviews the pathophysiology, evaluation, and treatment of severe asthma exacerbations, or status asthmaticus.

Management of children with severe asthma exacerbation in the emergency department

Although acute asthma is a very common cause of emergency department visits in children, there is as yet insufficient evidence for the establishment of a standardized treatment protocol. The aim of this review is to describe updated information on the management of asthma exacerbations in the pediatric emergency department. Oxygen is the first-line treatment of acute asthma exacerbations in the emergency department to control hypoxemia. It is accompanied by the administration of beta(2)-adrenoceptor agonists followed by corticosteroids. beta(2)-Adrenoceptor agonists have traditionally been administered by nebulization, although spacers have recently been introduced and proven, in many cases, to be as effective as nebulization. Oral prednisolone, with its reliability, simplicity, convenience and low cost, should remain the treatment of choice for the most severe asthma exacerbations, when the lung airways are extremely contracted and filled with secretions. Recently, several studies have shown that high-dose inhaled corticosteroids are at least as effective as oral corticosteroids in controlling moderate to severe asthma attacks in children and therefore should be considered an alternative treatment to oral corticosteroids in moderate to severe asthma attacks. Studies of other drugs have shown that ipratropium bromide may be given only in addition to beta(2)-adrenoceptor agonists; theophylline has no additional benefit, and magnesium sulfate has no clear advantage. Comprehensive asthma management should also include asthma education, measures to prevent asthma triggers, and training in the use of inhalers and spacers. Proper management will avoid most asthma attacks and reduce admission and readmission to emergency departments.

Drug therapy approaches in the treatment of acute severe asthma in hospitalised children

Acute severe paediatric asthma remains a serious and debilitating disease throughout the world. The incidence and mortality from asthma continue to increase. Early, effective and aggressive outpatient therapy is essential in reducing symptoms and preventing life-threatening progression. When complications occur or when the disease progresses to incipient respiratory failure, these children need to be managed in a continuous care facility where aggressive and potentially dangerous interventions can be safely instituted to reverse persistent bronchospasm. The primary drugs for acute severe asthma include oxygen, corticosteroids, salbutamol (albuterol) and anticholinergics. Second-line drugs include heliox, magnesium sulfate, ketamine and inhalational anaesthetics. Future therapies may include furosemide, leukotriene modifiers, antihistamines and phosphodiesterase inhibitors. This review attempts to explore the multitude of medications available with emphasis on pharmacology and pathophysiology.

Status asthmaticus in children: a review

About 10% of American children have asthma, and its prevalence, morbidity, and mortality have been increasing. Asthma is an inflammatory disease with edema, bronchial constriction, and mucous plugging. Status asthmaticus in children requires aggressive treatment with beta-agonists, anticholinergics, and corticosteroids. Intubation and mechanical ventilation should be avoided if at all possible, as the underlying dynamic hyperinflation will worsen with positive-pressure ventilation. If mechanical ventilation becomes necessary, controlled hypoventilation with low tidal volume and long expiratory time may lessen the risk of barotrauma and hypotension. Unusual and nonestablished therapies for severe asthma are discussed.

[Acute asthmatic crisis in children]

Acute asthma attack in children is an attack responsible for life-threatening acute respiratory distress with partial or no response to bronchodilator drugs. The severity of the episode needs to be quickly evaluated. This presupposes a perfect knowledge of the clinical signs of severity. Treatment is urgent and first based on the administration of high doses of inhaled short-acting beta 2-agonists. In the more obstructed children, anti-cholinergic drugs can be added to nebulized beta 2-agonists. Because of their delayed effect, systemic steroids require an early prescription. Symptomatic treatments are: urgent hospitalization, oxygen if needed, proper hydratation. Continuous nebulization or intravenous perfusion of beta 2-agonists are prescribed with cardiac monitoring when no objective improvement is noted. Admission into the pediatric intensive care unit when bronchial obstruction continues will permit the association of bronchodilator drugs and the proposal of mechanical ventilation if needed. When the episode is resolved, a prophylactic treatment using inhaled corticosteroids must be prescribed. Clinical and spirometric follow-up has to be organized, and the patient and his/her family have to be educated.

Status asthmaticus

Despite improved understanding of the pathophysiology and treatment of asthma, significant morbidity and mortality exist for both the pediatric and adult patient. The critical care practitioner must understand the chronic as well as the acute nature of the condition in order to provide effective intervention. This article reviews the epidemiology and pathophysiology of asthma, clinical assessment, management principles, therapeutic modalities, and future approaches to the management of asthma.

Alternatives to Standard Status Asthmaticus Therapy

Even with the currently available treatment, morbidity and mortality from asthma continues to rise. Patients with status asthmaticus who do not respond to standard therapy are at risk for respiratory failure and possible mechanical ventilation. Treatment options for refractory status asthmaticus remain limited and alternative and controversial therapies may need to be considered. Alternative therapies include continuous nebulized beta-agonists, ipratropium bromide, intravenous magnesium sulfate, ketamine, or heliox. Morbidity and mortality may be decreased by increased utilization of these alternative therapies. Pharmacists can play a key role in monitoring and recommending new and alternate therapies.

Acute management of severe childhood asthma

Severe childhood asthma is a serious, life-threatening disease that presents a challenge for patients, families, and caregivers. Despite evolving medical and pharmacologic therapies, the incidence and severity of asthma are increasing. Vasoactive substances are released in response to environmental and intrinsic triggers and result in bronchospasm, bronchial mucosal edema, and mucus plugging of the airways. Early recognition of symptoms and prompt, aggressive treatment, including oxygen, beta agonists, corticosteroids, and anticholinergic agents, are essential in halting the progression of asthma symptoms. In the most severe cases, intubation, mechanical ventilation, and treatment with anesthetic agents may be needed to avoid significant morbidity and mortality. This article reviews epidemiology, pathophysiology, and acute care of the child experiencing an acute asthma exacerbation.

Theophylline in acute childhood asthma: a meta-analysis of its efficacy

Although theophylline is a widely used drug for the treatment of acute childhood asthma, its efficacy has not been clearly established. This study constitutes a meta-analysis of published randomized clinical trials of theophylline in children hospitalized with acute asthma. We conducted a search of English language MEDLINE citations from 1966 to 1995 and analyzed the methods of each report meeting study criteria. We pooled similar clinical measures across studies if a test for homogeneity of effect size was non-significant. The six methodologically acceptable randomized clinical trials included a total of 164 children less than 18 years of age. Incomplete reporting of measures and variances was common. No study included children in intensive care settings. Using pooled results, pulmonary function parameters [forced expired volume in 1 second (FEV1), forced expired flow (FEF)] appeared better at 24 hours in the theophylline group, but the results did not reach statistical significance (mean effect difference, + 3.9% predicted values; pooled effect size, + 1.6 SDS; P = 0.25). A mean of 2.1 more albuterol treatments were administered in the theophylline group (pooled effect size, - 0.18 SDS; P = 0.02), and the mean hospital stay was slightly longer (mean effect difference, - 0.31 days; pooled effect size, - 0.18 SDS; P = 0.03). We conclude that currently available data do not indicate a significant beneficial effect of theophylline in children hospitalized with acute asthma. There is evidence for weak detrimental effects. Theophylline efficacy in intensive care unit settings remains unstudied.

Assessment of respiratory distress in the asthmatic child: when should we be concerned?

The physician caring for the acutely ill asthmatic child has a wide variety of signs and systems to assist in assessment. An assessment of the severity of the disease should be based on the medical history, and signs and symptoms due to hypoxia on various target organs. Laboratory evaluation, while helpful, has limited applicability in the young child but should be used as an adjunct to clinical assessment where necessary. Based on the history, physical examination, and laboratory assessment (when appropriate), acute asthma symptoms should be categorized as mild, moderate, or severe. Treatment then can be tailored to disease severity.