Clinical review: severe asthma.
Severe asthma, although difficult to define, includes all cases of difficult/therapy-resistant disease of all age groups and bears the largest part of morbidity and mortality from asthma. Acute, severe asthma, status asthmaticus, is the more or less rapid but severe asthmatic exacerbation that may not respond to the usual medical treatment. The narrowing of airways causes ventilation perfusion imbalance, lung hyperinflation, and increased work of breathing that may lead to ventilatory muscle fatigue and life-threatening respiratory failure. Treatment for acute, severe asthma includes the administration of oxygen, beta2-agonists (by continuous or repetitive nebulisation), and systemic corticosteroids. Subcutaneous administration of epinephrine or terbutaline should be considered in patients not responding adequately to continuous nebulisation, in those unable to cooperate, and in intubated patients not responding to inhaled therapy. The exact time to intubate a patient in status asthmaticus is based mainly on clinical judgment, but intubation should not be delayed once it is deemed necessary. Mechanical ventilation in status asthmaticus supports gas-exchange and unloads ventilatory muscles until aggressive medical treatment improves the functional status of the patient. Patients intubated and mechanically ventilated should be appropriately sedated, but paralytic agents should be avoided. Permissive hypercapnia, increase in expiratory time, and promotion of patient-ventilator synchronism are the mainstay in mechanical ventilation of status asthmaticus. Close monitoring of the patient's condition is necessary to obviate complications and to identify the appropriate time for weaning. Finally, after successful treatment and prior to discharge, a careful strategy for prevention of subsequent asthma attacks is imperative.
Papiris
Spyros
S
Department of Critical Care and Pulmonary Services, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece. papiris@otenet.gr
Kotanidou
Anastasia
A
Malagari
Katerina
K
Roussos
Charis
C
D000208:Acute Disease; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000627:therapeutic use; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D001784:Blood Gas Analysis; D004562:Electrocardiography; D006439:Hemodynamics; D006760:Hospitalization; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000627:therapeutic use; D007442:Intubation, Intratracheal; D008991:Monitoring, Physiologic; D011379:Prognosis; D013902:Radiography, Thoracic; D012008:Recurrence; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D012138:Respiratory Therapy; D012307:Risk Factors; D013224:Status Asthmaticus / Q000175:diagnosis / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D013997:Time Factors; D014057:Tomography, X-Ray Computed
D000305:Adrenal Cortex Hormones; D000318:Adrenergic beta-Agonists; D018927:Anti-Asthmatic Agents; D006993:Hypnotics and Sedatives