Am. J. Respir. Crit. Care Med.,
Volume 158, Number 5, November 1998, 1403-1409
Altered Lung Mechanics after Double-Lung
Transplantation
RAANAN
ARENS,
JOSEPH M.
MCDONOUGH,
HUAQING
ZHAO,
NANCY P.
BLUMENTHAL,
ROBERT M.
KOTLOFF,
and
MICHAEL M.
GRUNSTEIN
Divisions of Pulmonary Medicine, Biostatistics and Epidemiology, Children's Hospital of Philadelphia, Department of Pediatrics;
and Divisions of Pulmonary and Critical Care, University of Pennsylvania Medical Center, University of Pennsylvania School
of Medicine, Philadelphia, Pennsylvania
We studied lung mechanics and small airways function in 15 patients after double-lung (DL) transplantation. Patients were classified as stable (DL-S, n = 11), or having obliterative bronchiolitis syndrome (DL-OBS, n = 4). We performed pulmonary function tests (PFT), measured slope of phase 3 of
the single-breath nitrogen test (N2SP3), and obtained pressure-volume curves and values: chord
compliance (Cst,L), specific chord compliance (SCst,L), and elastic recoil pressure at 90% TLC. PFT
showed mild restrictive pattern in DL-S and severe obstructive lung disease in DL-OBS. The N2SP3
measurement indicated small airways dysfunction in 82% of DL-S and in all DL-OBS patients. The
Cst,L was 0.24 ± 0.08 L/cm H2O in DL-S and 0.16 ± 0.05 L/cm H2O in DL-OBS, both lower than control subjects 0.34 ± 0.09 L/cm H2O (p < 0.01; p < 0.001). Moreover, SCst,L was 0.09 ± 0.03 cm H2O
1
in DL-S, and 0.05 ± 0.02 cm H2O1 in DL-OBS, significantly lower than control subjects 0.12 ± 0.02 cm
H2O1 (p < 0.05; p < 0.001). Elastic recoil at 90% TLC was normal in 14 of 15 patients. We found a
linear correlation between N2SP3 and FEV1, and between FEV1 and Cst,L and SCst,L for combined DL-S and DL-OBS. Reduced compliance near FRC with normal elastic recoil at high lung volumes does not
suggest changes in lung parenchyma. We speculate that structural or functional alterations in small airways may have contributed to low compliance measurements. Of special concern are our findings
that DL-S had significant small airways dysfunction and reduced compliance in a pattern similar to
the DL-OBS, only smaller in magnitude.
