Halothane, an effective infrequently used drug, in the treatment of pediatric status asthmaticus: a case report

Volatile anesthetic agents for life-threatening pediatric asthma: A multicenter retrospective cohort study and narrative review

BACKGROUND

Volatile anesthetic agents are described as rescue therapy for children invasively ventilated for critical asthma. Yet, data are currently limited to case series.

AIMS

Using the Virtual Pediatric Systems database, we assessed children admitted to a pediatric intensive care unit invasively ventilated for life-threatening asthma and hypothesized ventilation duration and mortality rates would be lower for subjects exposed to volatile anesthetics compared with those without exposure.

METHODS

We performed a multicenter retrospective cohort study among nine institutions including children 5-17 years of age invasively ventilated for asthma from 2013 to 2019 with and without exposure to volatile anesthetics. Primary outcomes were ventilation duration and mortality. Secondary outcomes included patient characteristics, length of stay, and anesthetic-related adverse events. A subgroup analysis was performed evaluating children intubated ≥2 days.

RESULTS

Of 203 children included in study, there were 29 (14.3%) with and 174 (85.7%) without exposure to volatiles. No differences in odds of mortality (1.1, 95% CI: 0.3-3.9, p > .999) were observed. Subjects receiving volatiles experienced greater median difference in length of stay (4.8, 95% CI: 1.9-7.8 days, p < .001), ventilation duration (2.3, 95% CI: 1-3.3 days, p < .001), and odds of extracorporeal life support (9.1, 95% CI: 1.9-43.2, p = .009) than those without volatile exposure. For those ventilated ≥2 days, no differences were detected in mortality, ventilation duration, length of stay, arrhythmias, or acute renal failure. However, the odds of extracorporeal life support remained greater for those receiving volatiles (7.6, 95% CI: 1.3-44.5, p = .027). No children experienced malignant hyperthermia or hepatic failure after volatile exposure.

CONCLUSIONS

For intubated children for asthma, no differences in mechanical ventilation duration or mortality between those with and without volatile anesthetic exposure were observed. Although volatiles may represent a viable rescue therapy for severe cases of asthma, definitive, and prospective trials are still needed.

Sevoflurane Therapy for Severe Refractory Bronchospasm in Children

OBJECTIVES

To describe the effect of inhaled sevoflurane in the treatment of severe refractory bronchospasm in children.

DESIGN

Retrospective case series.

SETTING

Two PICUs of tertiary general university hospitals in Spain.

PATIENTS

Ten patients ranging from 5 months to 14 years old with severe bronchospasm and acute respiratory failure requiring tracheal intubation and mechanical ventilation and treated with sevoflurane from 2008 to 2015.

INTERVENTION

Inhaled sevoflurane therapy was initiated after failure of conventional medical management and mechanical ventilation. In two patients, sevoflurane was administered through a Servo 900C ventilator (Maquet, Bridgewater, NJ) equipped with a vaporizer and in the other eight patients via the Anesthetic Conserving Device (AnaConDa; Sedana medical, Uppsala, Sweden) with a critical care ventilator.

MEASUREMENTS AND MAIN RESULTS

Inhaled sevoflurane resulted in statistically significant decreases of PaCO2 of 34.2 torr (95% CI, 8.3-60), peak inspiratory pressure of 14.3 cm H2O (95% CI, 8.6-19.9), and improvement in pH of 0.17 (0.346-0.002) within 6 hours of administration. Only one patient presented hypotension responsive to volume administration at the beginning of the treatment. All patients could be extubated within a median time of 120 hours (interquartile range, 46-216).

CONCLUSIONS

Inhaled sevoflurane therapy decreases the levels of PaCO2 and peak inspiratory pressure values, and it may be considered as a rescue therapy in patients with life-threatening bronchospasm refractory to conventional therapy.

Volatile anesthetics for status asthmaticus in pediatric patients: a comprehensive review and case series

Status asthmaticus is an acute, intractable asthma attack refractory to standard interventions that can lead to progressive respiratory failure. Successful management requires a fundamental understanding of the disease process, its clinical presentation, and proper evaluation. Treatment must be instituted early and is aimed at reversing the airway inflammation, bronchoconstriction, and hyper-reactivity that often lead to lower airway obstruction, impaired ventilation, and oxygenation. Most patients are effectively treated with standard therapy including beta2-adrenergic agonists and corticosteroids. Others necessitate adjunctive therapies and escalation to noninvasive ventilation or intubation. We will review the pathophysiology, evaluation, and treatment options for pediatric patients presenting with status asthmaticus with a particular focus on refractory status asthmaticus treated with volatile anesthetics. In addition, we include a proven approach to the management of these patients in the critical care setting, which requires close coordination between critical care and anesthesia providers. We present a case series of three patients, two of which have the longest reported cases of continuous isoflurane use in status asthmaticus. This series was obtained from a retrospective chart review and highlights the efficacy of the volatile anesthetic, isoflurane, in three pediatric patients with refractory life-threatening status asthmaticus.

Sevoflurane therapy for life-threatening asthma in children

BACKGROUND

Asthma is a common disease in children and often develops early in life. This multicentre retrospective case series describe the use and effectiveness of sevoflurane inhalation therapy in a series of children with severe asthma in the paediatric intensive care unit (PICU).

METHODS

Seven children ranging from 4 to 13 yr of age admitted to the PICU of two tertiary care hospitals in the Netherlands were included. They all were admitted with the diagnosis of severe asthma requiring invasive mechanical ventilation and were treated with sevoflurane inhalation therapy.

RESULTS

The median (range) Pco2 level at the start, after 2 h, and at the end of sevoflurane treatment were 14 (5.1-24.8), 9.8 (5.4-17.0), and 6.2 (4.5-11.4) kPa (P=0.05) while the median (range) pH was 7.02 (6.97-7.36), 7.18 (7.04-7.35), and 7.43 (7.15-7.47) kPa (P=0.01), respectively. The median (range) peak pressure values declined from 30 (23-56) to 20.4 (14-33) cm H2O (P=0.03). No severe adverse effects besides hypotension, with sufficient response to norepinephrine treatment, were seen.

CONCLUSIONS

Sevoflurane inhalation corrects high levels of Pco2 and provides clinical improvement in mechanically ventilated children with life-threatening asthma who fail to respond to conventional treatment.

Volatile anesthetic rescue therapy in children with acute asthma: innovative but costly or just costly?

OBJECTIVES

To describe volatile anesthesia (VA) use for pediatric asthma, including complications and outcomes.

DESIGN

Retrospective cohort study.

SETTING

Children's hospitals contributing to the Pediatric Health Information System between 2004-2008.

PATIENTS

Children 2-18 years old with a primary diagnosis code for asthma supported with mechanical ventilation.

INTERVENTION

Those treated with VA were compared to those not treated with VA or extracorporeal membrane oxygenation. Hospital VA use was grouped as none, <5%, 5-10% and >10% among intubated children.

MEASUREMENTS AND MAIN RESULTS

One thousand five hundred and fifty-eight patients received mechanical ventilation at 40 hospitals for asthma: 47 (3%) received VA treatment at 11 (28%) hospitals. Those receiving a VA were significantly less likely to receive inhaled b-agonists, ipratropium bromide, and heliox, but more likely to receive neuromuscular blocking agents than patients treated without VA. Length of mechanical ventilation, hospital stay (length of stay [LOS]) and charges were significantly greater for those treated with VA. Aspiration was more common but death and air leak did not differ. Patients at hospitals with VA use >10% were significantly less likely to receive inhaled b agonist, ipratropium bromide, methylxanthines, and heliox, but more likely to receive systemic b agonist, neuromuscular blocking agents compared to those treated at hospitals not using VA. LOS, duration of ventilation, and hospital charges were significantly greater for patients treated at centers with high VA use.

CONCLUSIONS

Mortality does not differ between centers that use VA or not. Patients treated at centers with high VA use had significantly increased hospital charges and increased LOS.

Pediatric status asthmaticus

Status asthmaticus is a frequent cause of admission to a pediatric intensive care unit. Prompt assessment and aggressive treatment are critical. First-line or conventional treatment includes supplemental oxygen, aerosolized albuterol, and corticosteroids. There are several second-line treatments available; however, few comparative studies have been performed and in the absence of good evidence-based treatments, the use of these therapies is highly variable and dependent on local practice and provider preference. In this article the pathophysiology and treatment of status asthmaticus is discussed, and the literature regarding second-line treatments is critically assessed to apply an evidence basis to the treatment of this severe disease.

Acute severe asthma: new approaches to assessment and treatment

The precise definition of a severe asthmatic exacerbation is an issue that presents difficulties. The term 'status asthmaticus' relates severity to outcome and has been used to define a severe asthmatic exacerbation that does not respond to and/or perilously delays the repetitive or continuous administration of short-acting inhaled beta(2)-adrenergic receptor agonists (SABA) in the emergency setting. However, a number of limitations exist concerning the quantification of unresponsiveness. Therefore, the term 'acute severe asthma' is widely used, relating severity mostly to a combination of the presenting signs and symptoms and the severity of the cardiorespiratory abnormalities observed, although it is well known that presentation does not foretell outcome. In an acute severe asthma episode, close observation plus aggressive administration of bronchodilators (SABAs plus ipratropium bromide via a nebulizer driven by oxygen) and oral or intravenous corticosteroids are necessary to arrest the progression to severe hypercapnic respiratory failure leading to a decrease in consciousness that requires intensive care unit (ICU) admission and, eventually, ventilatory support. Adjunctive therapies (intravenous magnesium sulfate and/or others) should be considered in order to avoid intubation. Management after admission to the hospital ward because of an incomplete response is similar. The decision to intubate is essentially based on clinical judgement. Although cardiac or respiratory arrest represents an absolute indication for intubation, the usual picture is that of a conscious patient struggling to breathe. Factors associated with the increased likelihood of intubation include exhaustion and fatigue despite maximal therapy, deteriorating mental status, refractory hypoxaemia, increasing hypercapnia, haemodynamic instability and impending coma or apnoea. To intubate, sedation is indicated in order to improve comfort, safety and patient-ventilator synchrony, while at the same time decrease oxygen consumption and carbon dioxide production. Benzodiazepines can be safely used for sedation of the asthmatic patient, but time to awakening after discontinuation is prolonged and difficult to predict. The most common alternative is propofol, which is attractive in patients with sudden-onset (near-fatal) asthma who may be eligible for extubation within a few hours, because it can be titrated rapidly to a deep sedation level and has rapid reversal after discontinuation; in addition, it possesses bronchodilatory properties. The addition of an opioid (fentanyl or remifentanil) administered by continuous infusion to benzodiazepines or propofol is often desirable in order to provide amnesia, sedation, analgesia and respiratory drive suppression. Acute severe asthma is characterized by severe pulmonary hyperinflation due to marked limitation of the expiratory flow. Therefore, the main objective of the initial ventilator management is 2-fold: to ensure adequate gas exchange and to prevent further hyperinflation and ventilator-associated lung injury. This may require hypoventilation of the patient and higher arterial carbon dioxide (PaCO(2)) levels and a more acidic pH. This does not apply to asthmatic patients intubated for cardiac or respiratory arrest. In this setting the post-anoxic brain oedema might demand more careful management of PaCO(2) levels to prevent further elevation of intracranial pressure and subsequent complications. Monitoring lung mechanics is of paramount importance for the safe ventilation of patients with status asthmaticus. The first line of specific pharmacological therapy in ventilated asthmatic patients remains bronchodilation with a SABA, typically salbutamol (albuterol). Administration techniques include nebulizers or metered-dose inhalers with spacers. Systemic corticosteroids are critical components of therapy and should be administered to all ventilated patients, although the dose of systemic corticosteroids in mechanically ventilated asthmatic patients remains controversial. Anticholinergics, inhaled corticosteroids, leukotriene receptor antagonists and methylxanthines offer little benefit, and clinical data favouring their use are lacking. In conclusion, expertise, perseverance, judicious decisions and practice of evidence-based medicine are of paramount importance for successful outcomes for patients with acute severe asthma.

Inhalational anesthesia: basic pharmacology, end organ effects, and applications in the treatment of status asthmaticus

The potent inhalational anesthetic agents are used on a daily basis to provide intraoperative anesthesia. Given their beneficial effects on airway tone and reactivity, they also have a role in the treatment of status asthmaticus that is refractory to standard therapy. Although generally not of clinical significance, these agents can affect various physiological functions. The potent inhalational anesthetic agents decrease mean arterial pressure and myocardial contractility. The decrease in mean arterial pressure reduces renal and hepatic blood flow. Secondary effects on end-organ function may result from the metabolism of these agents and the release of inorganic fluoride. The following article reviews the history of inhalational anesthesia, the physical structure of the inhalational anesthetic agents, their end-organ effects, reports of their use for the treatment of refractory status asthmaticus in the intensive care unit (ICU) patient, and special considerations for their administration in this setting including equipment for their delivery, scavenging, and monitoring.

Prolonged sevoflurane inhalation therapy for status asthmaticus in an infant

A 3-month-old boy with retractive breathing from his birth was scheduled for a rigid bronchoscopic examination. Anesthesia was induced and maintained with sevoflurane. The examination revealed a slight laryngomalacia which was not compatible with his severe symptom. During the procedure, no respiratory deterioration occurred. He was once extubated in the operating room, however, developed severe desaturation immediately. He was reintubated at the scene and returned to the ward being mechanically ventilated and sedated. The next day, his respiratory condition worsened gradually. Conventional drugs including theophylline, corticosteroid and beta adrenergic agonist did not improve his deleterious condition. He became bradycardic and was on the verge of circulatory collapse as his lungs were unable to ventilate. Then, we commenced inhalation of sevoflurane using a standard anesthesia machine, which relieved him from ventilatory crisis. Although there were some difficulties in using anesthesia machine in the ICU, we could successfully manage mechanical ventilation. After the beginning of sevoflurane inhalation, his condition improved gradually. Discontinuation of sevoflurane was difficult and it took 94 h to wean from sevoflurane inhalation. Despite long duration of inhalation, no adverse effects of sevoflurane were observed except transient mild increase in liver transaminase. There have been very few reports on application of sevoflurane inhalation for such a long period in infants with bronchospasm. Moreover, measured serum fluoride concentration (24.2 micromol x l(-1)) during inhalation was well below harmful level. Sevoflurane inhalation is worth attempting and safe to treat life-threatening bronchospasm even in infants.

Near-fatal asthma: recognition and management

PURPOSE OF REVIEW

Near-fatal asthma continues to be a significant problem despite the decline in overall asthma mortality. The purpose of this review is to discuss recent advances in our understanding of the pathophysiology, diagnosis and treatment of near-fatal asthma.

RECENT FINDINGS

Two distinctive phenotypes of near-fatal asthma have been identified: one with eosinophilic inflammation associated with a gradual onset and a slow response to therapy and a second phenotype with neutrophilic inflammation that has a rapid onset and rapid response to therapy. Patients who develop sudden-onset near-fatal asthma seem to have massive allergen exposure and emotional distress. In stable condition, near-fatal asthma frequently cannot be distinguished from mild asthma. Diminished perception of dyspnea plays a relevant role in treatment delay, near-fatal events, and death in patients with severe asthma. Reduced compliance with anti-inflammatory therapy and ingestion of medications or drugs (heroin, cocaine) have been associated with fatal or near-fatal asthma.

SUMMARY

Near-fatal asthma is a subtype of asthma with unique risk factors and variable presentation that requires early recognition and aggressive intervention.