Bronchoscopic suctioning may cause lung collapse: a lung model and clinical evaluation.
OBJECTIVE
To assess lung volume changes during and after bronchoscopic suctioning during volume or pressure-controlled ventilation (VCV or PCV).


METHODS
Bench test and patient study.


METHODS
Ventilator-treated acute lung injury (ALI) patients.


METHODS
University research laboratory and general adult intensive care unit of a university hospital.


METHODS
Bronchoscopic suctioning with a 12 or 16 Fr bronchoscope during VCV or PCV.


RESULTS
Suction flow at vacuum levels of -20 to -80 kPa was measured with a Timeter(trade mark) instrument. In a water-filled lung model, airway pressure, functional residual capacity (FRC) and tidal volume were measured during bronchoscopic suctioning. In 13 ICU patients, a 16 Fr bronchoscope was inserted into the left or the right main bronchus during VCV or PCV and suctioning was performed. Ventilation was monitored with electric impedance tomography (EIT) and FRC with a modified N(2) washout/in technique. Airway pressure was measured via a pressure line in the endotracheal tube. Suction flow through the 16 Fr bronchoscope was 5 l/min at a vacuum level of -20 kPa and 17 l/min at -80 kPa. Derecruitment was pronounced during suctioning and FRC decreased with -479+/-472 ml, P<0.001.


CONCLUSIONS
Suction flow through the bronchoscope at the vacuum levels commonly used is well above minute ventilation in most ALI patients. The ventilator was unable to deliver enough volume in either VCV or PCV to maintain FRC and tracheal pressure decreased below atmospheric pressure.
Lindgren
S
S
Department of Anaesthesia and Intensive Care, Sahlgrenska University Hospital, SE-413 45, Gothenburg, Sweden. sophie.lindgren@vgregion.se
Odenstedt
H
H
Erlandsson
K
K
Grivans
C
C
Lundin
S
S
Stenqvist
O
O
D001999:Bronchoscopy / Q000009:adverse effects* / Q000379:methods; D003422:Critical Care / Q000379:methods; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008991:Monitoring, Physiologic; D012121:Respiration, Artificial / Q000379:methods; D012128:Respiratory Distress Syndrome / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D013396:Suction / Q000009:adverse effects / Q000379:methods; D013990:Tidal Volume