Factors Effecting the Outcome of Acute Respiratory Dis tress Syndrome in Pediatric Patients Treated with High Frequency Oscillatory Ventilation
SORASAK LOCHINDARAT, MD*, PANIDA SRISAN, MD*, PRAVIT JATANACHAI,MD*
Affiliation : * Division of Pediatric Pulmonology, Department of Pediatrics, Queen Sirikit National Institute of Child Health, Bangkok I 0400, Thailand.
Objectives : To evaluate the survival rate and factors affecting the outcome of pediatric patients treated with high-frequency oscillatory ventilation (HFOV) for diffuse alveolar disease (DAD) com patible with acute respiratory distress syndrome (ARDS).
Method : A cohort study was conducted at the pediatric intensive care unit of Queen Siritkit National Institute of Child Health from 1" January 1999 to 31" December 2001. Children who suffered from DAD compatible with ARDS were enrolled. Inclusion criteria were Pa0/Fi0 < 200 and oxygena 2 tion index (01) > 10. High-frequency oscillatory ventilator (3100A Sensor Medics Corp, Yorba Linda, Calif) was used applying high volume strategy of treatment. Patients were weaned to conventional ventilation (CV) once clinical improvement occurred. Demographic data, duration of CV mode- before changing to HFOV, duration of HFOV, ventilator parameters and gas exchange variables from begin ning and during the course of HFOV were recorded, so patient data could be compared between survi ving and non-surviving groups.
Results : A total of 21 children were enrolled during the 3 year period. There were 4 patients with simultaneous air leak syndrome and a total of 10 male patients. The average age was 3.58 ± 3.9 years. There were II surviving patients (52.4% ). Data of ventilator parameters and gas exchange vari ables after changing to HFOV for 4-6 hours for the two groups, Fi0 was higher (0.99 ± 0.32 vs 0.84 ± 0.18; p = 0.02) and alveolar arterial oxygen gradient [P(A-a)0 ] wa2 s lower (448.5 ± 140.8 vs 562.7 ± = 2 99.9 mmHg; p 0.047) in the surviving group than in the non-surviving group. Concerning mean airway pressure (Paw), oxygenation index (01), P(A-a)0 and Pa0/Fi0 at initiation and during the 2 2 course of HFOV with comparison of the surviving and non-surviving groups: Paw and 01 decreased in the surviving group and was significantly different at 36 and 24 hours respectively. P(A-a)0 was 2 statistically significantly lower at 6 hours after HFOV initiation in the surviving group. Pa0/Fi0 was 2 statistically significantly increased at 24 hours in the surviving group.
Conclusion : Implement of HFOV is useful in patients with DAD, ARDS and air leak syn drome from the initial phase of illness which fulfill criteria for decreasing ventilator induced lung injury and thus decrease the mortality rate from ARDS. Predisposing survival factor showing statistically significant differences was lower Paw during CV before changing to HFOV, lower Paw at 36 hours, lower 01 at 24 hours, lower P(A-a)0 at 6 hours and higher Pa0/Fi0 at 24 hours. These parameters 2 2 are good indicators for the prognosis of ARDS for patients responding or not responding to HFOV.
Keywords : acute respiratory distress syndrome, high-frequency oscillatory ventilation
