Risk factors for the development of reversible psychomotor dysfunction following prolonged isoflurane inhalation in the general intensive care unit

An Exploratory Study of Sevoflurane as an Alternative for Difficult Sedation in Critically Ill Children

OBJECTIVES

To analyze the effectiveness of inhaled sevoflurane in critically ill children with challenging sedation.

DESIGN

Prospective case series.

SETTING

Two PICUs of university hospitals in Spain.

INTERVENTIONS

Prospective observational study and exploratory investigation conducted in two PICUs in Madrid, Spain, over a 6-year period. Children treated with inhaled sevoflurane due to difficult sedation were included. Sevoflurane was administered via the anesthetic conserving device (AnaConDa) connected to a Servo-I ventilator (Maquet, Solna, Sweden). A morphine infusion was added to sevoflurane for analgesia. Demographic and clinical data, oral and IV sedatives, Sedation and Analgesic Clinical scores, and Bispectral Index Score monitoring were registered.

MEASUREMENTS AND MAIN RESULTS

Twenty-three patients with a median age of 6 months old were included. Fifty percentage of the patients had critical heart diseases. Sedative and analgesic drugs used before starting sevoflurane were mainly midazolam (63%) and fentanyl (53%). Six patients (32%) also received muscle relaxants. Sevoflurane was administered for a median of 5 days (interquartile range, 5.5-8.5 d). Median end-tidal sevoflurane concentration was 0.8% (interquartile range, 0.7-0.85%), achieved with an infusion rate of 7.5 mL/hr (5.7-8.6 mL/hr). After 48 hours of treatment, some sedative drugs could be removed in 18 patients (78%). Median Bispectral Index Score value prior to sevoflurane administration was 61 (interquartile range, 49-62), falling to 42 (interquartile range, 41-47; p < 0.05) after 6 hours of treatment. Six patients (26%) presented withdrawal syndrome after sevoflurane suspension, and all of them had received sevoflurane at least for 6 days. The main side effect was moderate hypotension in seven patients (30%).

CONCLUSIONS

Inhaled sevoflurane appeared to be an effective sedative agent in critically ill children and can be useful in those patients on mechanical ventilation difficult to sedate with conventional drugs. It can be administered easily in the PICU with conventional ventilators using the AnaConDa system. Withdrawal syndrome may occur with prolonged treatment.

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.