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Partitioning the respiratory effects of airway citric acid and normal saline in lambs
Author(s) -
Hutchison Alastair A.,
Caton Donald,
Thomas Ronald G.,
Bucciarelli Richard L.
Publication year - 1987
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950030112
Subject(s) - citric acid , saline , medicine , anesthesia , hyperventilation , respiratory system , arterial blood , airway , ventilation (architecture) , chemistry , biochemistry , mechanical engineering , engineering
Aspiration is common in the intubated human neonate. Thus, the ventilatory and blood gas responses to citric acid and saline instillation into different airway sites were studied in ten awake, unanesthetised lambs, breathing spontaneously via a tracheostomy tube. With a system of balloons, 1 ml of saline or citric acid was placed selectively into the midtrachea, the laryngeal area, or the lower trachea (lower tr). Changes in minute ventilation (V̇ E ), after a 30 sec baseline period, were measured 30 sec and 1 and 2 min after the challenge. Arterial blood gas changes were measured at 30 sec and 2 min. Major increases in V̇ E were seen only when saline or citric acid was instilled into the lower tr, the citric acid responses exceeding saline ones. The arterial oxygen tension (Pa O 2 ) fell after lower tr saline, whereas the arterial CO 2 tension (Pa CO 2) fell with midtracheal saline instillation. A rise in pH and a fall in Pa CO 2accompanied citric acid given into the lower tr. An initial rise in PaO 2 after citric acid into the lower tr was followed by a return to baseline despite hyperventilation. The ventilatory and blood gas changes with saline and citric acid depend on the site of airway instillation. Pediatr Pulmonol 1987; 3:45–50 .