Inflation lung mechanics deteriorates markedly after saline instillation and open endotracheal suctioning in mechanically ventilated healthy piglets.
BACKGROUND
Non-bronchoscopic bronchoalveolar lavage is an alternative to diagnostic bronchoscopy in pediatric patients, as fiberoptic bronchoscopes with aspiration channels are too large for small infants. There are many variations of the method in clinical practice, and saline instillation followed by open endotracheal suctioning is still commonly used. Lung function can deteriorate with these procedures, and we have investigated the effects on lung mechanics and oxygenation in healthy piglets.


METHODS
The lungs of anesthetized and mechanically ventilated piglets were recruited with CPAP 35 cmH2O. Thereafter we instilled 5 ml of saline into the endotracheal tube, followed by three breaths from the ventilator. Saline was retrieved through a suction catheter wedged far distally in the airway. The procedure was followed by a new recruitment maneuver. Complete inspiratory/expiratory pressure - volume loops (PV-loops) were obtained just before and 5 min after saline instillation. Arterial blood gases were collected at equivalent times in 14 similar piglets submitted to exactly the same procedure.


RESULTS
The inspiratory limb of the PV-loops changed markedly, as the lower inflection point was displaced towards higher pressures (P=0.004), and hysteresis measured at 15 and 30 cmH2O increased (P=0.004 and P=0.012, respectively). Although PaO2 decreased significantly (P=0.001), values after saline instillation/suctioning were still in the high normal range, that is, 22.2 +/- 2.6 kPa.


CONCLUSIONS
Opening pressures of the lungs increase markedly after saline instillation/suctioning in healthy piglets. In this situation, adequate recruitment maneuvers and PEEP might prevent lung collapse and deteriorations in arterial oxygenation.
Cunha-Goncalves
Doris
D
Department of Cardiovascular and Thoracic Anesthesia, Heart and Lung Division, University Hospital of Lund, Sweden. Doris.Cunha_Goncalves@med.lu.se
Perez-de-Sá
Valéria
V
Ingimarsson
Jónas
J
Werner
Olof
O
Larsson
Anders
A
D000818:Animals; D018893:Bronchoalveolar Lavage / Q000009:adverse effects / Q000379:methods; D007442:Intubation, Intratracheal / Q000009:adverse effects; D008170:Lung Compliance; D023421:Models, Animal; D010092:Oximetry; D012121:Respiration, Artificial / Q000009:adverse effects; D015656:Respiratory Mechanics; D012965:Sodium Chloride / Q000008:administration & dosage; D013396:Suction / Q000009:adverse effects; D013552:Swine
D012965:Sodium Chloride