Isoflurane therapy for severe refractory status asthmaticus in children

Guidelines for inhaled sedation in the ICU

INTRODUCTION AND OBJECTIVES

Sedation is used in intensive care units (ICU) to improve comfort and tolerance during mechanical ventilation, invasive interventions, and nursing care. In recent years, the use of inhalation anaesthetics for this purpose has increased. Our objective was to obtain and summarise the best evidence on inhaled sedation in adult patients in the ICU, and use this to help physicians choose the most appropriate approach in terms of the impact of sedation on clinical outcomes and the risk-benefit of the chosen strategy.

METHODOLOGY

Given the overall lack of literature and scientific evidence on various aspects of inhaled sedation in the ICU, we decided to use a Delphi method to achieve consensus among a group of 17 expert panellists. The processes was conducted over a 12-month period between 2022 and 2023, and followed the recommendations of the CREDES guidelines.

RESULTS

The results of the Delphi survey form the basis of these 39 recommendations - 23 with a strong consensus and 15 with a weak consensus.

CONCLUSION

The use of inhaled sedation in the ICU is a reliable and appropriate option in a wide variety of clinical scenarios. However, there are numerous aspects of the technique that require further study.

Outcomes of children with life-threatening status asthmaticus requiring isoflurane therapy and extracorporeal life support

BACKGROUND

Severe, refractory asthma is a life-threatening emergency that may be treated with isoflurane and extracorporeal life support. The objective of this study was to describe the clinical response to isoflurane and outcomes after discharge of children who received isoflurane and/or extracorporeal life-support for near-fatal asthma.

METHODS

This was a retrospective descriptive study using electronic medical record data from two pediatric intensive care units within a single healthcare system in Atlanta, GA.

RESULTS

Forty-five children received isoflurane, and 14 children received extracorporeal life support, 9 without a trial of isoflurane. Hypercarbia and acidosis improved within four hours of starting isoflurane. Four children died during the index admission for asthma. Twenty-seven percent had a change in Functional Status Score of three or more points from baseline to PICU discharge. Patients had median percent predicted FEV1 and FEV1/FVC ratios pre- and post-bronchodilator values below normal pediatric values.

CONCLUSION

Children who received isoflurane and/or ECLS had a high frequency of previous PICU admission and intubation. Improvement in ventilation and acidosis occurred within the first four hours of starting isoflurane. Children who required isoflurane or ECLS may develop long-lasting deficits in their functional status. Children with near-fatal asthma are a high-risk group and require improved follow-up in the year following PICU discharge.

Asthma Cases Treated With Inhaled Anesthetics or Extracorporeal Membrane Oxygenation: A Virtual Pediatric Systems Database Study of Outcomes

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) and/or inhaled anesthetics (IAs) are considered in the management of asthma when refractory to conventional therapy. We aimed to compare the outcomes of these two modalities in asthma PICU care and determine associated survival to hospital discharge among patients in a United States database.

DESIGN

Retrospective analysis using the Virtual Pediatric Systems (VPS, LLC) database.

SETTING

PICUs participating in the VPS database.

PATIENTS

Patients less than 18 years old with diagnosis of asthma treated with IA and/or ECMO from January 2010 to December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 221 patients were included; 149 (67%) received ECMO, 62 (28%) received IA, and 10 (5%) received both interventions. We failed to identify any difference between the ECMO and IA groups in demographics, Pediatric Index of Mortality 2 percentage, Pediatric Risk of Mortality 3 score, Pediatric Logistic Organ Dysfunction score, or pre-intervention pH and Paco2 levels. Use of ECMO versus IA was associated with lower pre-intervention Pao2 (60 torr [7.99 kPa] vs 78 torr [10.39 kPa]; p < 0.001) and higher utilization of high-frequency oscillatory ventilation. We failed to identify an association between type of intervention (IA vs ECMO) and greater odds of survival (57/62 [92%] vs 128/149 [86%]; odds ratio [OR], 1.87; 95% CI, 0.67-5.21; p = 0.23). However, these data do not exclude the possibility that IA use is associated with more than five-fold greater odds of survival. ECMO use was associated with longer duration of intervention (5 vs 1.3 d; p < 0.001) and PICU length of stay (LOS) (13 vs 7 d; p < 0.001). As expected, ECMO versus IA was also associated with greater odds of undergoing bronchoscopy (34% vs 11%; OR, 3.7; 95% CI, 1.5-9.4; p = 0.004).

CONCLUSIONS

In the VPS database of asthma management cases, we failed to identify an association between ECMO versus IA use and survival to hospital discharge. However, ECMO was associated with longer duration of intervention and PICU LOS.

General Anesthesia in Early Childhood Significantly Reduces Asthma Incidence and Clinical Visits: A Nationwide Population-Based Cohort Study

Few studies have focused on the consequence of exposure to general anesthesia (GA) in children’s early life with the risk of asthma and disease outcomes. The present study examines the correlation between exposure to GA under three years old and the subsequent course of asthma in a nationwide population-based cohort study. Our cases were acquired from Taiwan’s National Health Insurance Research Database (NHIRD). Children under three years old with either GA exposure or not during in-patient treatment from 1997 to 2008 were included. The study group was age- and sex-matched with a ratio of 1:2 to create the control group for comparison. The cohort included 2261 cases with GA and 4522 cases without GA as a control group. The incidence of asthma onset was significantly reduced in patients with GA exposure under 3 three years old (hazard ratio 0.64 (95% confidence interval 0.57~0.72), p < 0.001). In addition, regardless of whether the asthmatic clinical visits were before or after GA exposure, asthma onset patients before GA exposure have significantly fewer clinical visits than those without GA exposure (both p < 0.001, respectively). Using the Kaplan–Meier method, we also demonstrated that GA exposure was associated with favorable clinical visits in patients with asthma, whether their asthma was onset before GA (p = 0.0102) or after GA exposure (p = 0.0418) compared to non-GA-exposed controls. In the present study, we demonstrated that children with early GA exposure under three years old were at a reduced risk of developing asthma compared to the general population. Furthermore, we first reported that GA exposure significantly reduced clinical visits in patients with asthma regardless of whether their asthma onset was before or after GA exposure. It is indicated that GA exposure at a younger age could have potential clinical benefits for asthma than non-GA-exposed controls.

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.

TIVA versus Inhalational Agents for Pediatric Cardiac Intensive Care

The field of pediatric intensive care has come a long way, especially with the recognition that adequate sedation and analgesia form an imperative cornerstone of patient management. With various drugs available for the same, the debate continues as to which is the better: total intravenous anesthesia (TIVA) or inhalational agents. While each have their own advantages and disadvantages, in the present era of balance toward the IV agents, we should not forget the edge our volatile agents (VAs) might have in special scenarios. And ultimately as anesthesiologists, let us not forget that be it knob and dial, or syringe and plunger, our aim is to put pain to sleep and awaken a new faith to breathe.

Volatile Isoflurane in Critically Ill Coronavirus Disease 2019 Patients-A Case Series and Systematic Review

Objectives:

The ongoing coronavirus pandemic is challenging, especially in severely affected patients who require intubation and sedation. Although the potential benefits of sedation with volatile anesthetics in coronavirus disease 2019 patients are currently being discussed, the use of isoflurane in patients with coronavirus disease 2019–induced acute respiratory distress syndrome has not yet been reported.

Design:

We performed a retrospective analysis of critically ill patients with hypoxemic respiratory failure requiring mechanical ventilation.

Setting:

The study was conducted with patients admitted between April 4 and May 15, 2020 to our ICU.

Patients:

We included five patients who were previously diagnosed with severe acute respiratory syndrome coronavirus 2 infection.

Intervention:

Even with high doses of several IV sedatives, the targeted level of sedation could not be achieved. Therefore, the sedation regimen was switched to inhalational isoflurane. Clinical data were recorded using a patient data management system. We recorded demographical data, laboratory results, ventilation variables, sedative dosages, sedation level, prone positioning, duration of volatile sedation and outcomes.

Measurements & Main Results:

Mean age (four men, one women) was 53.0 (± 12.7) years. The mean duration of isoflurane sedation was 103.2 (± 66.2) hours. Our data demonstrate a substantial improvement in the oxygenation ratio when using isoflurane sedation. Deep sedation as assessed by the Richmond Agitation and Sedation Scale was rapidly and closely controlled in all patients, and the subsequent discontinuation of IV sedation was possible within the first 30 minutes. No adverse events were detected.

Conclusions:

Our findings demonstrate the feasibility of isoflurane sedation in five patients suffering from severe coronavirus disease 2019 infection. Volatile isoflurane was able to achieve the required deep sedation and reduced the need for IV sedation.

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.

Criteria for Critical Care Infants and Children: PICU Admission, Discharge, and Triage Practice Statement and Levels of Care Guidance

OBJECTIVES

To update the American Academy of Pediatrics and Society of Critical Care Medicine's 2004 Guidelines and levels of care for PICU.

DESIGN

A task force was appointed by the American College of Critical Care Medicine to follow a standardized and systematic review of the literature using an evidence-based approach. The 2004 Admission, Discharge and Triage Guidelines served as the starting point, and searches in Medline (Ovid), Embase (Ovid), and PubMed resulted in 329 articles published from 2004 to 2016. Only 21 pediatric studies evaluating outcomes related to pediatric level of care, specialized PICU, patient volume, or personnel. Of these, 13 studies were large retrospective registry data analyses, six small single-center studies, and two multicenter survey analyses. Limited high-quality evidence was found, and therefore, a modified Delphi process was used. Liaisons from the American Academy of Pediatrics were included in the panel representing critical care, surgical, and hospital medicine expertise for the development of this practice guidance. The title was amended to "practice statement" and "guidance" because Grading of Recommendations, Assessment, Development, and Evaluation methodology was not possible in this administrative work and to align with requirements put forth by the American Academy of Pediatrics.

METHODS

The panel consisted of two groups: a voting group and a writing group. The panel used an iterative collaborative approach to formulate statements on the basis of the literature review and common practice of the pediatric critical care bedside experts and administrators on the task force. Statements were then formulated and presented via an online anonymous voting tool to a voting group using a three-cycle interactive forecasting Delphi method. With each cycle of voting, statements were refined on the basis of votes received and on comments. Voting was conducted between the months of January 2017 and March 2017. The consensus was deemed achieved once 80% or higher scores from the voting group were recorded on any given statement or where there was consensus upon review of comments provided by voters. The Voting Panel was required to vote in all three forecasting events for the final evaluation of the data and inclusion in this work. The writing panel developed admission recommendations by level of care on the basis of voting results.

RESULTS

The panel voted on 30 statements, five of which were multicomponent statements addressing characteristics specific to PICU level of care including team structure, technology, education and training, academic pursuits, and indications for transfer to tertiary or quaternary PICU. Of the remaining 25 statements, 17 reached consensus cutoff score. Following a review of the Delphi results and consensus, the recommendations were written.

CONCLUSIONS

This practice statement and level of care guidance manuscript addresses important specifications for each PICU level of care, including the team structure and resources, technology and equipment, education and training, quality metrics, admission and discharge criteria, and indications for transfer to a higher level of care. The sparse high-quality evidence led the panel to use a modified Delphi process to seek expert opinion to develop consensus-based recommendations where gaps in the evidence exist. Despite this limitation, the members of the Task Force believe that these recommendations will provide guidance to practitioners in making informed decisions regarding pediatric admission or transfer to the appropriate level of care to achieve best outcomes.

The Use of Volatile Anesthetics as Sedatives for Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) remains to pose a high morbidity and mortality without any targeted therapies. Sedation, usually given intravenously, is an important part of clinical practice in intensive care unit (ICU), and the effect of sedatives on patients’ outcomes has been studied intensively. Although volatile anesthetics are not routine sedatives in ICU, preclinical and clinical studies suggested their potential benefit in pulmonary pathophysiology. This review will summarize the current knowledge of ARDS and the role of volatile anesthetic sedation in this setting from both clinical and mechanistic standpoints. In addition, we will review the infrastructure to use volatile anesthetics.

Targeted Versus Continuous Delivery of Volatile Anesthetics During Cholinergic Bronchoconstriction

Volatile anesthetics have been shown to reduce lung resistance through dilation of constricted airways. In this study, we hypothesized that that diffusion of inhaled anesthetics from airway lumen to smooth muscle would yield significant bronchodilation in vivo, and systemic recirculation would not be necessary to reduce lung resistance (RL ) and elastance (EL ) during sustained bronchoconstriction. To test this hypothesis, we designed a delivery system for precise timing of inhaled volatile anesthetics during the course of a positive pressure breath. We compared changes in RL , EL , and anatomic dead space (VD ) in canines (N=5) during pharmacologically-induced bronchoconstriction with intravenous methacholine, and following treatments with: 1) targeted anesthetic delivery to VD ; and 2) continuous anesthetic delivery throughout inspiration. Both sevoflurane and isoflurane were used during each delivery regimen. Compared to continuous delivery, targeted delivery resulted in significantly lower doses of delivered anesthetic and decreased end-expiratory concentrations. However, we did not detect significant reductions in RL or EL for either anesthetic delivery regimen. This lack of response may have resulted from an insufficient dose of the anesthetic to cause bronchodilation, or from the preferential distribution of air flow with inhaled anesthetic delivery to less constricted, unobstructed regions of the lung, thereby enhancing airway heterogeneity and increasing apparent RL and EL .

Sevoflurane improves respiratory mechanics and gas exchange in a case series of infants with severe bronchiolitis-induced acute respiratory distress syndrome

This report describes the successful use of a new intervention to improve respiratory mechanics and gas exchange in a relatively homogeneous group of infants with severe bronchiolitis‐induced PARDS after failure of conventional treatment. These results may open a new interesting area of research and management for PARDS patients.

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.

General anesthesia exposure in early life reduces the risk of allergic diseases: A nationwide population-based cohort study

General anesthesia (GA) has been used for second line treatment strategy for status asthmaticus in pediatric patients. The association between GA in children and risk of followed-up allergic diseases is unclear. This study aims to assess the risk of allergic diseases after GA in children.We did a nationwide retrospective cohort study by analyzing data from the National Health Insurance Research Database (NHIRD) in Taiwan. The subsequent risks for allergic diseases, including asthma (ICD-9: 493.X), allergic rhinitis (AR; ICD-9 CM code 477.X), and atopic dermatitis (AD; ICD-9-CM code 691.X), were compared between exposure to GA and none before 1 year of age throughout the follow-up period using the Cox proportional hazards model.Insurance claims data for 32,742 children younger than 1 year old from all insured children in the NHIRD. Of those, 2358 subjects were exposed to GA; 414 and 1944 children exposed to mask and intubation ventilation, respectively, served as the study cohort, whereas the remaining 30,384 children made up the comparison cohort. Children in the GA group were at a lower risk of developing asthma, AR and AD, with adjusted hazard ratios of 0.67 (0.62-0.72, 95%CI), 0.72 (0.68-0.77, 95%CI), 0.60 (0.56-0.64, 95%CI), respectively.Children who were exposed to GA in early life before 1 year of age had reduced risk of subsequently developing allergic diseases such as asthma, AD, and AR, when compared with general population.

Medication Repurposing in Pediatric Patients: Teaching Old Drugs New Tricks

OBJECTIVES

Gaps in pediatric therapeutics often result in off-label use and specifically, novel uses for existing medications, termed "drug repurposing." Drug Information (DI) queries to a Pediatric Medication Resource Center of a large metropolitan pediatric hospital in New York and inherent difficulties in retrieving evidence-based information prompted a review of current medication repurposing for pediatric patients. The objective included characterization of innovative off-label use of medications Food and Drug Administration (FDA)-approved for 1 or more indications to treat a totally different disorder or indication in pediatric patients.

METHODS

A systematic literature review was conducted to retrieve publications describing repurposed medications in pediatric patients. Excluded was FDA-approved indications used off-label in pediatric patients (e.g., different dose), preclinical data, adult use only, and experimental use. Evidence quality was classified using a modified American Academy of Neurology Level of Evidence. Results were analyzed using χ(2) at p < 0.05.

RESULTS

Over 2000 references were retrieved and reviewed. A total of 101 medications repurposed for novel off-label uses for pediatric patients were identified: 38 for neonates, 74 for children, and 52 for adolescents. Neonates and infants were least likely to receive a medication for a repurposed use. Strong or intermediate evidence existed in 80.2% of cases. The evidence was weak in 19.8%. No significant relationship was observed between the pediatric age group and strength of the literature. Most repurposed uses pertained to generic or widely used medications. Less than 5% of medications were first marketed after 2011.

CONCLUSIONS

While not exhaustive, the present study represents the most comprehensive listing of novel uses exclusive to pediatric patients. Further research is needed to identify the frequency of repurposed uses. The valuable DI role of pharmacists in assessing repurposed uses is of expanding and increasing importance to ensure such uses are evidence-based.

Volatile Agents in Medical and Surgical Intensive Care Units: A Meta-Analysis of Randomized Clinical Trials

OBJECTIVE

To comprehensively assess published randomized peer-reviewed studies related to volatile agents used for sedation in intensive care unit (ICU) settings, with the hypothesis that volatile agents could reduce time to extubation in adult patients.

DESIGN

Systematic review and meta-analysis of randomized trials.

SETTING

Intensive care units.

PARTICIPANTS

Critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The BioMedCentral, PubMed, Embase, and Cochrane Central Register databases of clinical trials were searched systematically for studies on volatile agents used in the ICU setting. Articles were assessed by trained investigators, and divergences were resolved by consensus. Inclusion criteria included random allocation to treatment (volatile agents versus any intravenous comparator, with no restriction on dose or time of administration) in patients requiring mechanical ventilation in the ICU. Twelve studies with 934 patients were included in the meta-analysis. The use of halogenated agents reduced the time to extubation (standardized mean difference = -0.78 [-1.01 to -0.55] hours; p for effect<0.00001; p for heterogeneity = 0.18; I(2) = 32% in 7 studies with 503 patients). Results for time to extubation were confirmed in all subanalyses (eg, medical and surgical patients) and sensitivity analyses. No differences in length of hospital stay, ICU stay, and mortality were recorded.

CONCLUSIONS

In this meta-analysis of randomized trials, volatile anesthetics reduced time to extubation in medical and surgical ICU patients. The results of this study should be confirmed by large and high-quality randomized controlled studies.

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.

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.

Continuous infusion, general anesthesia and other intensive care treatment for uncontrolled status epilepticus

PURPOSE OF REVIEW

To discuss the use of continuous infusions, general anesthesia, hypothermia, and ketogenic diet as treatment for uncontrolled status epilepticus in pediatric patients.

RECENT FINDINGS

Recent studies demonstrate that clinical practitioners have a hierarchy in approach in controlling refractory status epilepticus (RSE) and super-refractory status epilepticus in children. In the acute setting of RSE, midazolam achieves clinical seizure control at a mean of 41 min after starting an infusion. When midazolam has failed to control RSE, the evidence points to barbiturate anesthesia as the next frequently used option. When both midazolam and barbiturates have failed, use of isoflurane or ketamine anesthesia has been tried at a mean of 10 days after RSE onset, although the studies are largely anecdotal. Increasingly, the use of therapeutic hypothermia or ketogenic diet is described as a strategy for super-refractory status epilepticus, and better evidence for their use may become available from ongoing randomized studies.

SUMMARY

Uncontrolled episodes of status epilepticus require intensive care treatment and the literature describes a common pathway of care used by many. However, cases of truly refractory and super-refractory status epilepticus are seen infrequently at any given institution. One strategy to improve the quality of evidence is to develop prospective, national and multinational case registries to determine the range of presentations and causes, efficacy of treatments, and clinical outcomes.

Impact of the anesthetic conserving device on respiratory parameters and work of breathing in critically ill patients under light sedation with sevoflurane

BACKGROUND

Sevoflurane sedation in the intensive care unit is possible with a special heat and moisture exchanger called the Anesthetic Conserving Device (ACD) (AnaConDa; Sedana Medical AB, Uppsala, Sweden). The ACD, however, may corrupt ventilatory mechanics when used during the weaning process of intensive care unit patients. The authors compared the ventilatory effects of light-sedation with sevoflurane administered with the ACD and those of classic management, consisting of a heated humidifier and intravenous sedation, in intensive care unit patients receiving pressure-support ventilation.

METHODS

Fifteen intensive care unit patients without chronic pulmonary disease were included. A target Richmond Agitation Sedation Scale level of -1/-2 was obtained with intravenous remifentanil (baseline 1-condition). Two successive interventions were tested: replacement of the heated humidifier by the ACD without sedation change (ACD-condition) and sevoflurane with the ACD with an identical target level (ACD-sevoflurane-condition). Patients finally returned to baseline (baseline 2-condition). Work of breathing, ventilatory patterns, blood gases, and tolerance were recorded. A steady state of 30 min was achieved for each experimental condition.

RESULTS

ACD alone worsened ventilatory parameters, with significant increases in work of breathing (from 1.7 ± 1.1 to 2.3 ± 1.2 J/l), minute ventilation, P0,1, intrinsic positive end-expiratory pressure (from 1.3 ± 2.6 to 4.7 ± 4.2 cm H2O), inspiratory pressure swings, and decreased patient comfort. Sevoflurane normalized work of breathing (from 2.3 ± 1.2 to 1.8 ± 1 J/l), intrinsic positive end-expiratory pressure (from 4.7 ± 4.2 to 1.8 ± 2 cm H2O), inspiratory pressure swings, other ventilatory parameters, and patient tolerance.

CONCLUSIONS

ACD increases work of breathing and worsens ventilatory parameters. Sevoflurane use via the ACD (for a light-sedation target) normalizes respiratory parameters. In this patient's population, light-sedation with sevoflurane and the ACD may be possible during the weaning process.

Subanesthetic isoflurane reduces zymosan-induced inflammation in murine Kupffer cells by inhibiting ROS-activated p38 MAPK/NF-κB signaling

Volatile anesthetic isoflurane (ISO) has immunomodulatory effects. The fungal component zymosan (ZY) induces inflammation through toll-like receptor 2 or dectin-1 signaling. We investigated the molecular actions of subanesthetic (0.7%) ISO against ZY-induced inflammatory activation in murine Kupffer cells (KCs), which are known as the resident macrophages within the liver. We observed that ISO reduced ZY-induced cyclooxygenase 2 upregulation and prostaglandin E₂ release, as determined by western blot and radioimmunoassay, respectively. ISO also reduced the production of tumor necrosis factor-α, interleukin-1β, IL-6, high-mobility group box-1, macrophage inflammatory protein-1α, macrophage inflammatory protein-2, and monocyte chemoattractant protein-1 as assessed by enzyme-linked immunosorbent assays. ISO blocked the ZY-induced nuclear translocation and DNA-binding activity of nuclear factor- (NF)-κB p65. Moreover, ISO attenuated ZY-induced p38 mitogen-activated protein kinase (MAPK) activation partly by scavenging reactive oxygen species (ROS); the interregulation that ROS activated p38 MAPK followed by NF-κB activation was crucial for the ZY-induced inflammatory responses in KCs. An in vivo study by peritoneal injection of ZY into BALB/C mice confirmed the anti-inflammatory properties of 0.7% ISO against ZY in KCs. These results suggest that ISO ameliorates ZY-induced inflammatory responses in murine KCs by inhibiting the interconnected ROS/p38 MAPK/NF-κB signaling pathways.

Is pressure-regulated volume control mode appropriate for severely obstructed patients?

PURPOSE

Management of mechanical ventilation in severely obstructed patients remains controversial. Pressure-regulated volume control ventilation (PRVCV) has been suggested to be the best option, as it should ensure a prefixed tidal volume at the lowest peak inspiratory pressure. We sought to determine the accuracy of the delivered volume, compared with the programmed volume, when using PRVCV.

MATERIALS AND METHODS

Experimental work performing ventilation simulations using volume control ventilation (VCV), PRVCV, and pressure control ventilation (PCV). Each mode was tested at tidal volumes (TVs) of 200 and 500 mL at both low and high airway resistance. Evita XL and Servo-i ventilators were used.

RESULTS

At 200 ml TV with high resistance, volume delivered with Evita XL was 165 mL (95% confidence interval, 158-169) in VCV, 117 mL (95% confidence interval, 117-120) in PCV, and 120 (95% confidence interval, 115-121) in PRVCV (P<.001). Volume delivered with Servo-i was 133 mL (95% confidence interval, 130-136) in VCV, 108 mL (95% confidence interval, 104-111) in PCV, and 104 (95% confidence interval, 101-108) in PRVCV (P<.001).

CONCLUSIONS

In high-resistance simulations, the delivered volume was lower when using PCV or PRVCV modes than VCV mode. Pressure control ventilation or PRVCV may fail to provide programmed TV, ultimately leading to hypoventilation of the patient.

A review of the use of adjunctive therapies in severe acute asthma exacerbation in critically ill children

Asthma is a common and potentially life threatening childhood condition. Asthma involves not only chronic airway remodeling, but may also include frequent exacerbations resulting from bronchospasm, edema, and mucus production. In children with severe exacerbations, standard therapy with β2-agonists, anti-cholinergic agents, oxygen, and systemic steroids may fail to reverse the severe airflow obstruction and necessitate use of adjunctive therapies. These therapies include intravenous or inhaled magnesium, inhaled helium-oxygen mixtures, intravenous methylxanthines, intravenous β2-agonists, and intravenous ketamine. Rarely, these measures are not successful and following the initiation of invasive mechanical ventilation, inhaled anesthetics or extracorporeal life support may be required. In this review, we discuss the mechanisms and evidence for adjunctive therapies in the setting of severe acute asthma exacerbations in children.

Volatile Anesthetics and the Treatment of Severe Bronchospasm: A Concept of Targeted Delivery

Status asthmaticus (SA) is a severe, refractory form of asthma that can result in rapid respiratory deterioration and death. Treatment of SA with inhaled anesthetics is a potentially life-saving therapy, but remarkably few data are available about its mechanism of action or optimal administration. In this paper, we will review the clinical use of inhaled anesthetics for treatment of SA, the potential mechanisms by which they dilate constricted airways, and the side effects associated with their administration. We will also introduce the concept of 'targeted' delivery of these agents to the conducting airways, a process which may maximize their therapeutic effects while minimizing associated systemic side effects. Such a delivery regimen has the potential to define a rapidly translatable treatment paradigm for this life-threatening disorder.

A subanesthetic dose of isoflurane during postconditioning ameliorates zymosan-induced neutrophil inflammation lung injury and mortality in mice

Anesthetic isoflurane (ISO) has immunomodulatory effects. In the present study, we investigated whether a subanesthetic dose of ISO (0.7%) protected against zymosan (ZY) induced inflammatory responses in the murine lung and isolated neutrophils. At 1 and 6 hrs after ZY administration intraperitoneally, ISO was inhaled for 1 hr, and 24 hrs later, lung inflammation and injury were assessed. We found that ISO improved the survival rate of mice and mitigated lung injury as characterized by the histopathology, wet-to-dry weight ratio, protein leakage, and lung function index. ISO significantly attenuated ZY-induced lung neutrophil recruitment and inflammation. This was suggested by the downregulation of (a) endothelial adhesion molecule expression and myeloperoxidase (MPO) activity in lung tissue and polymorphonuclear neutrophils (b) chemokines, and (c) proinflammatory cytokines in BALF. Furthermore, ZY-induced nuclear translocation and DNA-binding activity of NF- κ B p65 were also reduced by ISO. ISO treatment inhibited iNOS expression and activity, as well as subsequent nitric oxide generation. Consistent with these in vivo observations, in vitro studies confirmed that ISO blocked NF- κ B and iNOS activation in primary mouse neutrophils challenged by ZY. These results provide evidence that 0.7% ISO ameliorates inflammatory responses in ZY-treated mouse lung and primary neutrophils.

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.

Management of status asthmaticus in children

Recent literature on paediatric status asthmaticus (PSA) confirms an increasing percentage of admissions to paediatric intensive care units. PSA is a medical emergency that can be fatal and needs careful and prompt intervention. The severity of PSA is mainly determined by clinical judgement of signs and symptoms. Peak flow measurements and serial lung function measurements are not reliable in PSA. Validated clinically useful instruments are lacking. The three main factors that are involved in the pathophysiology of PSA, bronchoconstriction, mucus plugging and airway inflammation need to be addressed to optimise treatment. Initial therapies include supplementation of oxygen, repetitive administration of rapid acting β2-agonists, inhaled anticholinergics in combination with systemic glucocorticosteroids and intravenous magnesium sulphate. Additional treatment modalities may include methylxanthines, DNase, ketamine, sodium bicarbonate, heliox, epinephrine, non-invasive respiratory support, mechanical ventilation and inhalational anaesthetics.

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.

A review of the practice of sedation with inhalational anaesthetics in the intensive care unit with the AnaConDa(®) device

The intensive care unit (ICU) environment is often perceived to be hostile and frightening by patients due to unfamiliar surroundings coupled with presence of numerous personnel, monitors and other equipments as well as a loss of perception of time. Mechanical ventilation and multiple painful procedures that often need to be carried out in these critically ill patients add to their overall anxiety. Sedation is therefore required not only to allay the stress and anxiety, but also to allow for mechanical ventilation and other invasive therapeutic and diagnostic procedures to be performed. The conventional intravenous sedative agents used in ICUs suffer from problems of over sedation, tachyphylaxis, drug accumulation, organ specific elimination and often lead to patient agitation on withdrawal. All this tend to prolong the ventilatory as well as ICU and hospital discharge time, which increase the risk for infection and add to the overall increase in morbidity, mortality and hospital costs. In 2005, the anaesthetic conserving device (AnaConDa(®)) was marketed for ICU sedation with volatile anaesthetic agents. A number of trials have shown the effectiveness of using volatile anaesthetic agents for ICU sedation with the AnaConDa device. Compared with intravenous sedatives, use of volatile anaesthetic agents have resulted in shorter wake up and extubation time, lesser duration of mechanical ventilation and faster discharge from hospitals. This review shall focus on the benefits, technical pre-requisites and status of sedation with volatile anaesthetic agents in ICUs with the AnaConDa(®) device.

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.

Pediatric intensive care treatment of uncontrolled status epilepticus

The critically ill mechanically ventilated child with ongoing seizures that are refractory to any treatment presents a distinct challenge in pediatric neurocritical care. The evidence base from randomized controlled trials on which anti-epileptic drug (AED) strategy should be used is inadequate. This review of refractory and super-refractory status epilepticus summarizes recent pediatric case series regarding definitions, the second-tier AED therapies once initial anticonvulsants have failed, and the experience of high-dose midazolam, barbiturate anesthesia, and volatile anesthetics for uncontrolled status epilepticus.

Ten common questions (and their answers) about off-label drug use

The term off-label drug use (OLDU) is used extensively in the medical literature, continuing medical education exercises, and the media. Yet, we propose that many health care professionals have an underappreciation of its definition, prevalence, and implications. This article introduces and answers 10 questions regarding OLDU in an effort to clarify the practice's meaning, breadth of application, acceptance, and liabilities. Off-label drug use involves prescribing medications for indications, or using a dosage or dosage form, that have not been approved by the US Food and Drug Administration. Since the Food and Drug Administration does not regulate the practice of medicine, OLDU has become common. It occurs in every specialty of medicine, but it may be more common in areas of medicine in which the patient population is less likely to be included in clinical trials (eg, pediatric, pregnant, or psychiatric patients). Pharmaceutical companies are not allowed to promote their medications for an off-label use, which has lead to several large settlements for illegal marketing. To limit liability, physicians should prescribe medications only for indications that they believe are in the best interest of the patient. In addition, health care professionals should educate themselves about OLDU to weigh the risks and benefits and provide the best possible care for their patients.

Isoflurane for life-threatening bronchospasm: a 15-year single-center experience

BACKGROUND

Children with severe bronchospasm requiring mechanical ventilation may become refractory to conventional therapy. In these critically ill patients, isoflurane is an inhaled anesthetic agent available in some centers to treat bronchospasm. We hypothesized that isoflurane is safe and would lead to improved gas exchange in children with life-threatening bronchospasm refractory to conventional therapy.

METHODS

A retrospective review was conducted and included mechanically ventilated children treated with isoflurane in a quaternary pediatric ICU for life-threatening bronchospasm, from 1993 to 2007. Demographic, blood gas, ventilator, and outcome data were collected.

RESULTS

Thirty-one patients, with a mean age of 9.5 years (range 0.4-23 years) were treated with isoflurane, from 1993 to 2007. Mean time to initiation of isoflurane after intubation was 13 hours (0-120 h), and the mean maximum isoflurane dose was 1.1% (0.3-2.5%). Mean duration of isoflurane administration was 54.5 hours (range 1-181 h), with a total mean duration of mechanical ventilation of 252 hours (range 16-1,444 h). Isoflurane led to significant improvement in pH and P(CO(2)) within 4 hours of initiation (P ≤ .001). Complications during isoflurane administration included hypotension requiring vasoactive infusions in 24 (77%), arrhythmia in 3 (10%), neurologic side effects in 3 (10%), and pneumothorax in 1 (3%) patient.

CONCLUSIONS

Isoflurane led to improvement in pH and P(CO(2)) within 4 hours in this series of mechanically ventilated patients with life-threatening bronchospasm. The majority of patients in this series developed hypotension, but there was a low incidence of other side effects related to isoflurane administration. Isoflurane appears to be an effective therapy in patients with life-threatening bronchospasm refractory to conventional therapy. However, further investigation is warranted, given the uncertain overall impact of isoflurane in this context.

Analgesia and sedation after pediatric cardiac surgery

In recent years, the importance of appropriate intra-operative anesthesia and analgesia during cardiac surgery has become recognized as a factor in postoperative recovery. This includes the early perioperative management of the neonate undergoing radical surgery and more recently the care surrounding fast-track and ultra fast-track surgery. However, outside these areas, relatively little attention has focused on postoperative sedation and analgesia within the pediatric intensive care unit (PICU). This reflects perceived priorities of the primary disease process over the supporting structure of PICU, with a generic approach to sedation and analgesia that can result in additional morbidities and delayed recovery. Management of the marginal patient requires optimisation of not only cardiac and other attendant pathophysiology, but also every aspect of supportive care. Individualized sedation and analgesia strategies, starting in the operating theater and continuing through to hospital discharge, need to be regarded as an important aspect of perioperative care, to speed the process of recovery.

[Functioning of the anaesthetic conserving device: aspects to consider for use in inhalational sedation]

The new anaesthetic conserving device (ACD) allows the use of isoflurane and sevoflurane without classical anaesthesia workstations. Volatile anaesthetic exhaled by the patient is absorbed by a reflector and released to the patient during the next inspiration. Liquid anaesthetic is delivered via a syringe pump. Currently the use of the ACD is spreading among European intensive care units (ICU). This article focuses on the functioning of the device and on particularities which are important to consider. The ACD constantly reflects 90% of the exhaled anaesthetic back to the patient, but if one exhaled breath contains more than 10 ml of anaesthetic vapour (e.g. >1 vol% in 1,000 ml), the capacity of the reflector will be exceeded and relatively more anaesthetic will be lost to the patient. This spill over decreases efficiency but it also contributes to safety as very high concentrations are averted. Compared to classical anaesthesia systems the ACD used in conjunction with ICU ventilators offers advantages in the ICU setting: investment costs are low, carbon dioxide absorbent is not needed, breathing comfort is higher, anaesthetic consumption is low (equal to an anaesthesia circuit with a fresh gas flow of approximately 1 l/min) and anaesthetic concentrations can be controlled very quickly (increased by small boluses and decreased by removal of the ACD). On the other hand, case costs are higher (single patient use) and a dead space of 100 ml is added. There are pitfalls: by a process called auto-pumping, expansion of bubbles inside the syringe may lead to uncontrolled anaesthetic delivery. Auto-pumping is provoked by high positioning of the syringe pump, heat and prior cooling of the liquid anaesthetic. Inherent to the device is an early inspiratory concentration peak and an end-inspiratory dip which may mislead commonly used gas monitors. Workplace concentrations can be minimized by proper handling, a sufficient turnover of room air is important and gas from the expiration port of the ventilator should be scavenged. Inhalational compared to intravenous ICU sedation offers the advantages of better control of the sedation level, online drug monitoring, no accumulation in patients with renal or hepatic insufficiency and bronchodilation. With a lowered opioid dose spontaneous breathing and intestinal motility are well preserved. A clinical algorithm for the care of patients with respiratory insufficiency including inhalational sedation is proposed. Inhalational sedation with isoflurane has been widely used for more than 20 years in many countries and even for periods of up to several weeks. In the German S3 guidelines for the management of analgesia, sedation and delirium in intensive care (Martin et al. 2010), inhalational sedation is mentioned as an alternative sedation method for patients ventilated via an endotracheal tube or a tracheal cannula. Nevertheless, isoflurane is not officially licensed for ICU sedation and its use is under the responsibility of the prescribing physician.

Long-term isoflurane therapy for refractory bronchospasm associated with herpes simplex pneumonia in a heart transplant patient

A 47-year-old man with a history of heart transplant was admitted after severe traumatic brain injury and seizures. During mechanical ventilation, the patient developed bronchospasm that severely compromised respiratory function that led to cardiac arrest. After resuscitation, application of isoflurane through the Anaesthetic Conserving Device (AnaConDa) in the ICU successfully treated bronchospasm, provided adequate sedation, and enabled appropriate ventilation and diagnostic bronchoscopy. A subsequent bronchoalveolar lavage revealed a high amount of Herpes simplex DNA. Herpes simplex pneumonia was diagnosed and treated with acyclovir. Isoflurane treatment was applied for twelve days total without side effects on renal and cerebral function. The patient recovered quickly after the termination of sedation. At discharge, he was fully awake without focal neurological deficiency and his long-term outcome was excellent. This case demonstrates that isoflurane is a treatment option in life-threatening cases of bronchospasm and a safe option for long-term sedation.

Trends in admissions for pediatric status asthmaticus in New Jersey over a 15-year period

OBJECTIVE

Status asthmaticus accounts for a large portion of the morbidity and mortality associated with asthma, but we know little about its epidemiology. We describe here the hospitalization characteristics of children with status asthmaticus, how they changed over time, and how they differed between hospitals with and without PICUs.

PATIENTS AND METHODS

We used administrative data from New Jersey that included all hospitalizations in the state from 1992, 1995, and 1999-2006. We identified children with status asthmaticus by using International Classification of Diseases, Ninth Revision, diagnosis codes that indicate status asthmaticus and the use of mechanical ventilation by using procedure codes. We designated hospitals with a PICU as "PICU hospitals" and those without as "adult hospitals."

RESULTS

We identified 28 309 admissions of children with status asthmaticus (22.8% of all asthma hospitalizations). From 1992 to 2006, the rate of hospital admissions decreased by half (from 1.98 in 1000 to 0.93 in 1000 children), and there was a 70% decrease in the number of children admitted to adult hospitals. The rate of ICU care in PICU hospitals more than tripled. However, the rate of mechanical ventilation remained low, and the number of deaths was small and unchanged (n=14 total). Hospital costs climbed from $6.6 million to $9.5 million.

CONCLUSIONS

Although fewer children are being admitted with status asthmaticus, the proportion of patients managed in PICUs is climbing. There has been no substantial change in rates of mechanical ventilation or death. Additional research is needed to better understand how patients and physicians decide on the appropriate site for hospital care and how that choice affects outcome.

[Sedation concepts with volatile anaesthetics in intensive care: practical use and current experiences with the AnaConDa system]

The use of volatile anaesthetics in intensive care medicine has so far been limited by the lack of equipment suitable for daily routine use and the need for an anaesthetic machine. The new Anaesthetic Conserving Device (AnaConDa) enables the routine use of volatile anaesthetics for long-term sedation via intensive care ventilators. The Anaesthetic Conserving Device replaces the common heat and moisture exchanger in the ventilation circuit. The volatile anaesthetic is continuously applied in liquid status via a syringe pump to a form of mini-vaporiser where the anaesthetic agent is vaporised. The expired anaesthetic gas is stored in the carbon filter and approximately 90% of the gas is resupplied into the breathing cycle. The current experiences suggest that volatile anaesthetics present an alternative for long-term sedation in intensive care units, providing optimised pathways, from a medical as well as from an economical point of view. It must, however, be emphasized that the use of volatile anaesthetics for longer periods of time is an off-label use and should only undertaken by medical professionals at their own risk.

Guideline-oriented perioperative management of patients with bronchial asthma and chronic obstructive pulmonary disease

Increased airway hyperresponsiveness is a major concern in the perioperative management of patients with bronchial asthma and chronic obstructive pulmonary disease. Guidelines using evidence-based medicine are continually being updated and published regarding the diagnosis, treatment, and prevention of these respiratory disorders. Perioperative management in these patients involves: (1) adequate control of airway hyperresponsiveness, including detection of purulent sputum and infection before surgery; (2) evidence-based control of anesthesia; and (3) the aggressive use of beta-2 adrenergic stimulants and the systemic administration of steroids for the treatment of acute attacks. Good preoperative control, including the use of leukotriene antagonists, can reduce the incidence of life-threatening perioperative complications. Awareness of recent guidelines is thus important in the management of patients with airway hyperresponsiveness. This review covers the most recent guidelines for the perioperative management of patients with bronchial asthma and chronic obstructive pulmonary disease.