Effect of prophylactic bronchodilator treatment on lung resistance after tracheal intubation.
BACKGROUND
After induction of anesthesia, lung resistance increases. We hypothesized that prophylactic bronchodilator treatment before tracheal intubation would result in a lower lung resistance after placement of the endotracheal tube.


METHODS
Forty-two adult patients were randomized to receive one of three inhaled medications 1 h before surgery. All patients first underwent pulmonary function tests. Patients then received either inhaled albuterol (360 micrograms) (n = 12), inhaled ipratropium bromide (72 micrograms) (n = 15) or a placebo inhalation (n = 15). Two, 5, and 15 min after tracheal intubation, lung resistance was measured using the method of von Neergard and Wirtz.


RESULTS
Patients who received either bronchodilator had significantly lower lung resistance after intubation than those receiving placebo. At 2 min, lung resistances were 12.7 +/- 1.4 cmH2O.l-1.s-1 (mean +/- SEM) for the placebo group, 6.4 +/- 3.1 cmH2O.l-1.s-1 for the ipratropium-treated group (P < 0.05 vs. placebo), and 7.2 +/- 0.8 cmH2O.l-1.s-1 for the albuterol-treated group (P < 0.05 vs. placebo). The differences in lung resistance persisted through the final measurement at 15 min. Three of fifteen placebo-treated patients developed audible wheezing whereas no patients developed wheezing in either bronchodilator-treated group (P < 0.05 by Fisher's exact test). Although smokers and nonsmokers in the placebo group developed similar resistances after intubation, bronchodilator treatment resulted in lower resistance in nonsmokers than in smokers (P < 0.05).


CONCLUSIONS
Prophylactic treatment with either an inhaled beta 2-adrenergic agonist or an inhaled cholinergic antagonist produced lower lung resistance after intubation when compared with an inhaled placebo medication. The effect was more pronounced in nonsmokers than in smokers.
Kil
H K
HK
Yonsei University College of Medicine, Seoul, Korea.
Rooke
G A
GA
Ryan-Dykes
M A
MA
Bishop
M J
MJ
D000280:Administration, Inhalation; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000009:adverse effects / Q000627:therapeutic use; D000758:Anesthesia / Q000379:methods; D016085:Bronchoconstrictor Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects*; D009241:Ipratropium / Q000627:therapeutic use; D007530:Isoflurane; D007823:Laryngeal Nerves / Q000502:physiology; D008168:Lung / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D012129:Respiratory Function Tests; D013990:Tidal Volume; D014132:Trachea / Q000294:innervation
D016085:Bronchoconstrictor Agents; D007530:Isoflurane; D009241:Ipratropium; D000420:Albuterol