Metabolic and cardiovascular responses following oral and nasal intubation of the trachea.

The cardiovascular and metabolic responses to oral and nasal intubation of the trachea were studied in 24 unpremedicated patients, free from cardiovascular disease and scheduled for excision of breast lump. Systolic blood pressure (SBP) and heart rate (HR) were recorded with a Dinamap 1846 SX before and at 1 minute intervals for 10 minutes following oral (group A = 12 patients) or nasal (group B = 12 patients) intubation. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured at 1 minute intervals for 10 minutes following tracheal intubation using the Engström Metabolic Computer and an infrared CO2 analyzer. No significant differences in SBP and HR preinduction and postintubation values were found between the two groups. Both oral and nasal intubation were associated with significant increases in VO2 (p less than 0.001 and p less than 0.001 respectively), VCO2 (p less than 0.001 and p less than 0.001), SBP (p less than 0.001 and p less than 0.001) and HR (p less than 0.001 and p less than 0.001). Nasal intubation of the trachea was associated with significantly higher VO2 (p less than 0.05-0.01) and VCO2 (p less than 0.05-0.001) values when compared with the VO2 and VCO2 values following oral intubations.