Tidal Volume Requirement in Mechanically Ventilated Infants with Meconium Aspiration Syndrome.
OBJECTIVE
The aim of the study is to test the hypothesis that increased physiologic dead space and functional residual capacity seen in meconium aspiration syndrome (MAS) results in higher tidal volume (VT) requirement to achieve adequate ventilation.


METHODS
Retrospective review of infants with MAS admitted to our hospital from 2000 to 2010 managed with conventional ventilation. Demographics, ventilator settings, VT, respiratory rate (RR), and blood gas values were recorded. Minute ventilation (MV) was calculated as RR × VT. Only VT values with corresponding partial pressure of carbon dioxide (Paco 2) between 35 and 60 mm Hg were included. Mean VT/kg and MV/kg were calculated for each patient. Forty infants ventilated for lung disease other than MAS or pulmonary hypoplasia served as controls.


RESULTS
Birth weights of the 28 MAS patients and 40 control infants were similar (3,330 ± 500 g and 3,300 ± 640 g). Two patients in each group required extracorporeal membrane oxygenation. Infants with MAS required 26% higher VT and 42% higher MV compared with controls to maintain equal Paco 2.


CONCLUSIONS
Infants with MAS require larger VT and higher total MV to achieve similar alveolar ventilation, consistent with pathophysiology of MAS. Our findings provide the first reference data to guide selection of VT in infants with MAS.
Division of Neonatology, Department of Pediatrics, Georgetown University Hospital, Washington, District of Columbia.
Saumya
S
Sharma
Genomic Medicine Division, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.
Shane
S
Clark
Division of Neonatology, Department of Pediatrics, Georgetown University Hospital, Washington, District of Columbia.
Kabir
K
Abubakar
Division of Neonatology, Department of Pediatrics, Women and Infants Hospital, Brown University, Providence, Rhode Island.
Martin
M
Keszler
D001784:Blood Gas Analysis; D002245:Carbon Dioxide; D016022:Case-Control Studies; D015331:Cohort Studies; D015199:Extracorporeal Membrane Oxygenation; D006801:Humans; D007231:Infant, Newborn; D008471:Meconium Aspiration Syndrome / Q000628:therapy*; D010313:Partial Pressure; D011175:Positive-Pressure Respiration / Q000379:methods*; D012121:Respiration, Artificial / Q000379:methods; D056152:Respiratory Rate; D012189:Retrospective Studies; D013990:Tidal Volume
D002245:Carbon Dioxide