The Science Journal of the American Association for Respiratory Care
Introduction: Respiratory Syncytial Virus (RSV) is the leading cause of lower respiratory tract infection in infants and children. Annually, tens of thousands of children are hospitalized. Signs and symptoms of RSV bronchiolitis include wheezing, hyperinflation of the lung, dyspnea, retractions, atelectasis, and mucous plugging with resultant increased work of breathing. Of those children hospitalized, approximately 5% require mechanical ventilation. Breathing a helium-oxygen mixture, due to the low-density of the gas, decreases airway resistance and work of breathing. This case study examines the benefit of adding a 60% helium-40% oxygen (Heliox) mixture to the ventilator circuit of a patient with RSV bronchiolitis. Case Summary: The patient is a 3 month 23 day old, 2.8 kg, 28 week gestation, twin, who was at home with the diagnosis of bronchopulmonary dysplasia. She was on Aminophylline and a monitor for apnea at the time of this illness. She presented to an outlying Emergency Department with apnea and required intubation. She was then transported to the CHSD PICU. Upon admission she was placed on a GALILEO ventilator (Hamilton Medical, inc.) with the ventilator settings P-SIMV, PIP of 39 cmH2O, PEEP of 5 cmH2O, respiratory rate (r) of 25, inspiratory time (IT) of 0.8 seconds, 50% oxygen. The Venous Blood Gas on these settings was pH= 7.24, CO2=54, BE= -4.5, oxygen saturation 100%. The patient's CO2 increased during the evening and Heliox therapy was initiated. The infant's ventilation improved dramatically on the addition of Heliox, with no change in ventilator settings or other therapies. Her oxygen saturation remained 100%. The following chart summarizes the blood gases pre and post Heliox therapy.
|Venous Blood Gas||pH||PCO2||BE||O2 Saturation|
|P-SIMV, 38/5, r.30, 0.7 IT. 50% Oxygen||7.16||92||+4||100%|
|P-SIMV, 38/5, r.30, 0.7 IT. Heliox||7.35||53||+2.5||100%|
Discussion: Heliox dramatically improved the ventilation of this intubated infant with RSV bronchiolitis with no change in ventilator settings. The benefits of Heliox mixtures for patients with asthma and airway obstruction are well documented. There is evidence that Heliox improves the overall respiratory status of children with RSV lower respiratory tract infection. More research is required to determine which patients with RSV bronchiolitis will benefit from this treatment.