Search

The newly developed supralaryngeal airway Streamlined Liner of the Pharynx Airway (SLIPA) has been compared successfully to the LMA, but the haemodynamic response to its insertion has not been evaluated in a randomised study. We compared haemodynamic and Bispectral index (BIS) responses to insertion of the SLIPA with classic LMA after standardising the anaesthetic technique using BIS to monitor and control the anaesthetic depth. One hundred patients were randomised to receive either a classic LMA or SLIPA following induction with fentanyl and propofol titrated to a target BIS of 40 and compared heart rate, mean arterial pressure and BIS responses to insertion. There was a significant rise in mean arterial pressure from the pre-stimulus value (73.8 [10.6] mmHg, mean +/- SD) at two and three minutes (P<0.05) following insertion of the LMA with maximum rise (80.8 [11.5] mmHg) seen at two minutes. There was a significant rise in mean arterial pressure from the pre-stimulus value (73.2 [12.6] mmHg) at one, two, three, four and five minutes (P<0.05) following insertion of the SLIPA with maximum rise (86.9 [15.1] mmHg) observed at three minutes. Mean arterial pressure was significantly higher (P<0.05) with SLIPA at two, three, four and five minutes. BIS increased significantly (P<0.05) at one, two, three, four and five minutes following insertion of both the devices, but there was no significant difference between the groups. There was a significantly higher (P=0.001) incidence of blood on the device with the SLIPA (20/50 vs. 6/50 with LMA). Thus, insertion of SLIPA causes significantly higher blood-pressure response but similar BIS response compared to the LMA.

Unlabelled: Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects. Magnesium has direct vasodilating properties on coronary arteries and inhibits catecholamine release, thus attenuating the hemodynamic effects during endotracheal intubation. We studied 36 patients with coronary artery disease (CAD) scheduled for elective coronary artery bypass grafting to evaluate the hemodynamic effects of magnesium and its efficacy in attenuating the response to endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before intubation. The hemodynamic variables were recorded before induction, after the trial drug, after induction, and after endotracheal intubation. Automatic ST segment analysis was performed throughout the study period. Magnesium sulfate administration was associated with increased cardiac index (P < 0.01), a minimal increase in heart rate, and a significant decrease in mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in the magnesium group had significant ST depression compared with three patients in the control group. The magnesium group patients had a significantly lesser increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group patients who received lidocaine before endotracheal intubation. Thus, magnesium is an useful adjuvant to attenuate endotracheal intubation response in patients with CAD., Implications: Endotracheal intubation produces adverse hemodynamic effects, which may be more detrimental in patients with coronary artery disease than in healthy patients. The present study shows that magnesium administered before endotracheal intubation can attenuate this response better than lidocaine.

Forty healthy patients (ASA class 1) of both sexes, aged between 20 and 45 years, undergoing routine surgical procedures were included in this double-blind randomized study. They were divided into two groups of 20 each. Patients in group A received no pretreatment, while patients in group B received oral clonidine 5 micrograms kg-1 90 min before induction of anesthesia. All patients received thiopentone (5 mgs kg-1) followed by suxamethonium (1.5 mgs kg-1) to facilitate endotracheal intubation. Control patients showed a significant increase in heart rate and blood pressure; they were significantly lower in the clonidine treated group immediately after intubation (p less than 0.001). The data suggest that the rise in heart rate and blood pressure associated with laryngoscopy and intubation during a routine induction sequence can be attenuated by the use of oral clonidine.

The efficacy of sublingual nifedipine in attenuating the pressor responses to laryngoscopy and intubation was studied in 40 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5.5 mg kg-1 i.v. and tracheal intubation was facilitated with suxamethonium 1.5 mg kg-1 i.v. Patients were allocated randomly to receive sublingual nifedipine 10 mg or placebo capsules 10 min before induction. Patients receiving placebo capsule showed significant increases in heart rate and arterial pressure associated with tracheal intubation (P less than 0.001). The increases in arterial pressure and rate-pressure product were reduced in nifedipine treated patients (P less than 0.001). Heart rate increased significantly in both groups immediately after intubation.

Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied to evaluate the efficacy of sublingual nifedipine in attenuating the intraocular pressure response to succinylcholine administration, laryngoscopy and intubation. The patients were randomly given either nifedipine 10 mg or placebo sublingually 20 minutes before induction of anaesthesia. Intraocular pressure (IOP) and systolic blood pressure (SBP) were recorded before and after induction of anaesthesia. The IOP response to succinylcholine administration, laryngoscopy and intubation was significantly less in patients receiving nifedipine (P less than 0.01). The mean maximum rise in IOP above basal level at one minute post-intubation was 7.82 mmHg in the control group compared with 0.15 mmHg in the nifedipine pre-treated group. These results suggest that sublingual nifedipine is effective in attenuating the IOP response after succinylcholine administration, laryngoscopy and intubation.