Cardiovasular changes after placement of a classic endotracheal tube, double-lumen tube, and Laryngeal Mask Airway.

STUDY OBJECTIVE

To compare hemodynamic responses, P wave dispersion (Pd), and QT dispersion (QTd) after placement of a classic endotracheal tube (ETT), double-lumen tube (DLT), or Laryngeal Mask Airway (LMA).

DESIGN

Prospective study.

SETTING

Outpatient surgery center.

PATIENTS

75 adult, ASA physical status 1 and 2 patients undergoing cystoscopy and thoracoscopic surgery.

INTERVENTIONS

Patients were randomized to undergo placement of an ETT (Group T; n = 25), DLT (Group D; n = 25), or LMA (Group L; n = 25). Anesthesia was induced by etomidate 0.3 mg/kg and fentanyl 1.0 μg/kg, and maintained with nitrous oxide, oxygen, 2% to 3% sevoflurane, and rocuronium 0.5 mg/kg.

MEASUREMENTS

Mean arterial pressure (MAP) and heart rate (HR) were recorded immediately before intubation and after intubation at one, 3, 5, 10,15, 20, 25, and 30 minutes after intubation/airway insertion.

RESULTS

QT dispersion after tube placement was significantly higher than before tube placement in Group D (P = 0.0001) and Group L (P = 0.03). Mean arterial pressure and HR in Group T were significantly higher than in Group L at the first minute after tube placement (P = 0.02). Heart rate and MAP at baseline were significantly higher than the other measurement times in Groups T and D (P < 0.01).

CONCLUSIONS

The LMA caused no change in Pd, HR, or MAP values during or after airway placement, but caused QTd after airway insertion. The ETT caused a sudden increase at the first minute after tube placement, without any Pd or QTd. In addition, DLT caused QTd without any serious change in hemodynamics.