Ventilation strategies in acute asthma

Abstract

Status asthmaticus is a condition of progressively worsening bronchospasm and respiratory dysfunction due to asthma, which is unresponsive to standard conventional therapy and may progress to respiratory failure. Despite initial aggressive management a small proportion of patients require ventilatory support. Ventilation in asthma is complex and presents a big challenge to the pediatric intensivist, with mortality rates in patients requiring ventilation approaching as high as 10%. It requires careful personalized management. NIV is increasingly being used and its early initiation has shown to improve outcome and avoid endotracheal intubation in some recent studies. During mechanical ventilation, our first goal is to maintain adequate gas exchange and the second goal is to minimize the risk of air trapping and auto PEEP. These goals are best achieved by adopting the strategy of controlled hypoventilation and permissive hypoxemia initially. Once recovery starts the patient is shifted to assisted or spontaneous mode. A cautious application of PEEP up to 80% of auto PEEP can be tried at this stage. Further recovery should prompt the intensivist to rapidly wean and extubate the patient. Intense pharmacotherapy must continue throughout ventilation. Caie should be taken to choose the most appropriate device for delivery of the aerosolized bronchodilators. Higher doses may be required to achieve the desired effect.