Topical anesthesia through tracheal tubing inhibited cardiovascular responses to tracheal intubation

Objective To investigate whether topical anesthesia of endotracheal and laryngopharynx through tracheal tubing inhibits cardiovascular responses to tracheal intubation. Methods Forty ASA grade Ⅰand Ⅱ patients(20-60 y) subjected to elective orthopedic surgery were assigned into test and control group(n=20). After anesthesia with midazolam, sufentanil, etomidate and vecuronium, manual ventilation was performed for 3 min. Then, a triplet tracheal tube was inserted from mouth into endotracheal within 30 s, and 1% tetracaine was quickly delivered into endotracheal and laryngopharynx through two tubes attached on the ventilation tube of the triplet tube. The tube was retained for mechanical ventilation throughout the operation. SBP, DBP, HR, epinephrine(E), noradrenaline(NE) and cortiso (Cor) were measured when patients entered into surgery room (T0), just before (T1) and after (T2) endotracheal, and 1 (T3), 3 (T4) min, and 5 (T5) min after intubation. Results Compared with levels at T0, SBPs were significantly increased(17%) only at T2 in test group(P 0.05) , but were significant increased by 18% (P<0.01) and 14% (P<0.05) at T2 and T3, respectively, in control group. Levels of serum E and NE in test group were significantly lower than those of control group at T3 and T5(P<0.05), and levels of serum Cor in test group were significantly lower than those of control group at T5(P<0.01). Conclusions Endotracheal and laryngopharynx topical anesthesia with tetracaine through modified tracheal tube markedly inhibited cardiovascular responses following endotracheal intubation. Key words: Triplet tracheal tube; Topical anesthesia; Tracheal intubation; Cardiovascular responses; Catecholamine