Impact of Cardiopulmonary Bypass on Respiratory Mucociliary Function in an Experimental Porcine Model.
BACKGROUND
The impact of cardiac surgery using cardiopulmonary bypass (CPB) on the respiratory mucociliary function is unknown. This study evaluated the effects of CPB and interruption of mechanical ventilation on the respiratory mucociliary system.


METHODS
Twenty-two pigs were randomly assigned to the control (n = 10) or CPB group (n = 12). After the induction of anesthesia, a tracheostomy was performed, and tracheal tissue samples were excised (T0) from both groups. All animals underwent thoracotomy. In the CPB group, an aorto-bicaval CPB was installed and maintained for 90 minutes. During the CPB, mechanical ventilation was interrupted, and the tracheal tube was disconnected. A second tracheal tissue sample was obtained 180 minutes after the tracheostomy (T180). Mucus samples were collected from the trachea using a bronchoscope at T0, T90 and T180. Ciliary beat frequency (CBF) and in situ mucociliary transport (MCT) were studied in ex vivo tracheal epithelium. Mucus viscosity (MV) was assessed using a cone-plate viscometer. Qualitative tracheal histological analysis was performed at T180 tissue samples.


RESULTS
CBF decreased in the CPB group (13.1 ± 1.9 Hz vs. 11.1 ± 2.1 Hz, p < 0.05) but not in the control group (13.1 ± 1 Hz vs. 13 ± 2.9 Hz). At T90, viscosity was increased in the CPB group compared to the control (p < 0.05). No significant differences were observed in in situ MCT. Tracheal histology in the CPB group showed areas of ciliated epithelium loss, submucosal edema and infiltration of inflammatory cells.


CONCLUSIONS
CPB acutely contributed to alterations in tracheal mucocilliary function.
Laboratory of Anesthesiology (LIM08), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Rodrigo
R
Sánchez-Véliz
Laboratory of Anesthesiology (LIM08), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Maria José
MJ
Carmona
Laboratory of Anesthesiology (LIM08), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Denise Aya
DA
Otsuki
Laboratory of Anesthesiology (LIM08), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Claudia
C
Freitas
Cardiac Surgery Division, Heart Institute (InCor), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Anderson
A
Benício
Department of Pathology, Experimental Air Pollution Laboratory, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Elnara Marcia
EM
Negri
Laboratory of Anesthesiology (LIM08), University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
Luiz Marcelo
LM
Malbouisson
D000818:Animals; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D009079:Mucociliary Clearance / Q000502:physiology*; D009093:Mucus / Q000502:physiology; D012137:Respiratory System; D013552:Swine; D019616:Thoracic Surgical Procedures / Q000009:adverse effects*; D014783:Viscosity