Intranasal nitroglycerine attenuates pressor response to tracheal intubation in beta-blocker treated hypertensive patients

The effect of intranasal nitroglycerine on the pressor response to laryngoscopy and tracheal intubation was studied in 40 adult hypertensive patients treated with beta-blocking drugs. Nitroglycerine 0.75 mg, administered intranasally 30 seconds before induction of anaesthesia, was compared with a placebo solution of saline. Haemodynamic variables were measured for 10 minutes after laryngoscopy and tracheal intubation. Heart rate did not change significantly in either group. Systolic as well as mean arterial blood pressure increased significantly for the first 5 minutes in the control group, whereas patients in the nitroglycerine group showed a decrease in systolic as well as in mean arterial pressure. No patient in the nitroglycerine group showed a decrease in systolic arterial pressure greater than 20 mmHg. In conclusion, intranasal nitroglycerine ameliorates the pressor response to laryngoscopy and tracheal intubation in beta-blocked patients.     

The intubating laryngeal mask airway with and without fiberoptic guidance

We conducted this feasibility study using the intubating laryngeal mask airway (ILMA) and a polyvinyl chloride tracheal tube to compare success rates, hemodynamic effects, and postoperative morbidity with two methods of tracheal intubation. After ethics approval and informed consent, 90 healthy ASA physical status I or II women with normal airways were enrolled in the randomized, controlled study. After a standardized inhaled anesthesia induction protocol, tracheal intubations using ILMA with fiberoptic guidance (ILMA-FOB) and ILMA inserted blindly without fiberoptic guidance (ILMA-Blind) were compared with the control group of direct laryngoscopy (laryngoscopy group). All 90 patients were successfully ventilated. For tracheal intubation, success rates were equal in all three groups (97%). Total intubation times were longer for the ILMA-FOB group (77 s versus 48.5 s for laryngoscopy and 53.5 s for ILMA-Blind). The laryngoscopy group had a larger increase in mean arterial blood pressure to tracheal intubation. There were no differences in postoperative sore throat or hoarseness among the groups. In conclusion, success rates are equally high for tracheal intubation using ILMA-Blind and ILMA-FOB techniques in women with normal airways. IMPLICATIONS: The intubating laryngeal mask airway (ILMA) can be used as a primary airway for oxygenation and ventilation. Both methods of tracheal intubation using the ILMA were equally successful. Postoperative morbidity in the ILMA groups was similar to that in the laryngoscopy group. For women with normal airways, both the ILMA inserted blindly and the ILMA with fiberoptic guidance are suitable alternatives to laryngoscopy for tracheal intubation.     

Ephedrine, dopamine, or doubtamine to treat hypotension with propofol during epidural anesthesia

PURPOSE: To compare the efficacy of ephedrine, dopamine and dobutamine for circulatory support during thoracic epidural anesthesia after anesthetic induction with propofol. METHODS: Forty patients undergoing lobectomy or mastectomy were divided into four groups of 10: a control group received no vasopressor; an ephedrine group received 5 mg ephedrine when the mean arterial pressure (MAP), measured every 2.5 min, decreased by 10% from baseline; dopamine and dobutamine groups received 5 microg x kg(-1) x min(-1) dopamine or 3 microg x kg(-1) x min(-1) dobutamine from five minutes after epidural injection of local anesthetic to the end of tracheal intubation. Anesthesia was induced with 2 mg x kg(-1) propofol. The MAP and heart rate (HR) were measured at baseline, 20 min after epidural injection, three minutes after propofol, and one minute after tracheal intubation. RESULTS: In the control group, MAP and HR decreased from 86+/-9 mmHg, 74+/-8 bpm to 62+/-9 mm Hg; P<0.0001, 60+/-8 bpm; P = 0.0003 after propofol. After tracheal intubation, MAP was restored to (81+/-13 mmHg, 70+/-13 bpm). In the ephedrine, dopamine, and dobutamine groups, MAP and HR remained unchanged during epidural anesthesia and propofol induction. However, after tracheal intubation, MAP and HR increased in the ephedrine (104+/-11 mm Hg; P = 0.004, 87+/-11 bpm; P<0.0001) and dobutamine (117+/-13 mm Hg; P = 0.0005, 100+/-11 bpm; P<0.0001) groups, but not in the dopamine group compared with baseline. CONCLUSION: Dopamine is preferable to ephedrine and dobutamine in providing hemodynamic stability during propofol induction and tracheal intubation following epidural anesthesia.     

Effects of clonidine premedication upon hemodynamic changes associated with laryngoscopy and tracheal intubation

The authors studied 30 patients undergoing general anesthesia in order to evaluate whether oral clonidine premedication could attenuate the hemodynamic changes associated with laryngoscopy and tracheal intubation. Patients were randomly assigned to one of two groups; clonidine group (n = 15) who received oral clonidine of approximately 5 micrograms.kg-1, or control group (n = 15) who received no clonidine. The magnitude of increases in mean blood pressure from baseline values following laryngoscopy and tracheal intubation in the clonidine group was significantly smaller as compared with that in the control group (20 +/- 12 vs. 31 +/- 14 mmHg, mean +/- SD, P less than 0.05). There was also a significant difference between the two groups in the incidence of systolic blood pressure increases above 180 mmHg following laryngoscopy and tracheal intubation (0% vs. 26%, P less than 0.05). However, no significant difference was noted between the two groups in the heart rate responses to laryngoscopy and tracheal intubation. It is concluded that oral clonidine of 5 micrograms.kg-1 as a preanesthetic medication could attenuate the pressor responses associated with laryngoscopy and tracheal intubation.     

Nifedipine attenuates the hypertensive response to tracheal intubation in pregnancy-induced hypertension

Thirty women with pregnancy-induced hypertension (PIH) scheduled for Caesarean section under general anaesthesia were studied to evaluate the efficacy of sublingual nifedipine in attenuating the pressor response to laryngoscopy and tracheal intubation. The patients were randomly given either the contents of a nifedipine capsule 10 mg or placebo sublingually 20 min before induction of anaesthesia. Blood pressure and heart rate were recorded at various time intervals. There was a decrease in mean arterial blood pressure (MAP) after pre-treatment with nifedipine (P < 0.01). The increase in MAP during laryngoscopy and intubation was higher in the control group compared with nifedipine pretreatment group (P < 0.01). During laryngoscopy and intubation, MAP decreased by 3 mmHg in the nifedipine pretreatment group, while there was an increase of 14 mmHg in the control group. Heart rate increased in both the groups during the laryngoscopy and tracheal intubation (P < 0.01) but the increase was higher in the nifedipine group than in the control group (P <0.05). Neonatal Apgar scores in both the groups were comparable. These results suggest that sublingual nifedipine is effective in attenuating the hypertensive response to laryngoscopy and intubation but not the tachycardiac response in parturients with PIH.     

Attenuation of the pressor response to laryngoscopy and tracheal intubation with intravenous verapamil

This study was undertaken in surgical patients in order to evaluate the effects of intravenous verapamil on the circulatory responses to laryngoscopy and tracheal intubation. Laryngoscopy for tracheal intubation was initiated 1 min after thiamylal 5 mg.kg-1 and succinylcholine 1.5 mg.kg-1 in the control group (n = 21). The verapamil group (n = 23) received intravenous verapamil 0.1 mg.kg-1 immediately after thiamylal-succinylcholine administration. The resulting changes in mean arterial pressure (MAP) and heart rate (HR) were continuously measured. Compared with the control group, MAP increased less in response to laryngoscopy and tracheal intubation (56 +/- 13% versus 25 +/- 15% above baselines, P less than 0.01) and returned toward baseline sooner in patients receiving verapamil. For hypertensive patients, MAP increases from baseline after intubation were 18 +/- 9% in the verapamil group, and 53 +/- 14% in the control group, respectively (P less than 0.001). Increases in HR response to laryngoscopy for intubation were comparable in both groups. We conclude that intravenous verapamil is effective in reducing pressor responses during endotracheal intubation, especially in hypertensive patients.     

The effect of diltiazem on the cardiovascular response to tracheal intubation

The efficacy of diltiazem in the attenuation of the cardiovascular response to laryngoscopy and tracheal intubation was studied in patients who received 0.2 or 0.3 mg/kg diltiazem 60 seconds before the start of laryngoscopy. These data were compared with a control group who received saline. Each group consisted of 10 patients who had elective surgery. Patients who received saline showed a significant increase in mean arterial pressure and rate pressure product associated with tracheal intubation. These increases after tracheal intubation were reduced in diltiazem-treated patients compared with those of the control group (p less than 0.05). The data suggest that a bolus injection of diltiazem is a simple, practical and effective method to attenuate the hypertensive response to laryngoscopy and tracheal intubation.     

Hemodynamic and catecholamine response to tracheal intubation: direct laryngoscopy compared with fiberoptic intubation

STUDY OBJECTIVE: To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberoptic bronchoscopy technique. DESIGN: Randomized, prospective study. SETTING: Operating rooms in a teaching hospital. PATIENTS: 51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used. MEASUREMENTS: Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and 1 and 5 minutes after intubation. MAIN RESULTS: Duration of intubation was shorter in the direct laryngoscopy group (16.9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine levels did not increase after intubation and did not correlate with the hemodynamic changes. CONCLUSIONS: The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine levels do not correlate with the hemodynamic changes.     

Propofol is superior to thiopental for intubation without muscle relaxants

PURPOSE: To compare intubating conditions and cardiovascular changes following induction of anesthesia and tracheal intubation in patients receiving either lidocaine-remifentanil-propofol or lidocaine-remifentanil-thiopental prior to induction. METHODS: In a randomized, double-blind study 76 healthy adult patients were assigned to one of two groups: lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and propofol 2 mg.kg(-1) (Group P) or lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and thiopental 5 mg.kg(-1) (Group T). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient's response to intubation and slow inflation of the tracheal cuff. The mean arterial pressure (MAP) and heart rate (HR) were measured 45 sec after hypnotic agent administration, immediately after tracheal intubation, two and five minutes after intubation. RESULTS: Excellent intubating conditions were obtained in 84% of Group P patients and 50% of Group T patients (P < 0.05). The percentage decrease from baseline MAP was significantly higher in Group P than in Group T postinduction (27.4% +/- 11.6 vs 21.8% +/- 10.0) and immediately postintubation (19.0% +/- 16.7 vs 11.2% +/- 14.9). The percentage change from baseline HR was significantly higher in Group P than in Group T postinduction (13.8% +/- 9.7 vs 0.5% +/- 12.4), immediately postintubation (8.7% +/- 13.7 vs 2.1% +/- 13.1), and two minutes postintubation (7.04% +/- 14.3 vs 3.5% +/- 14.3). CONCLUSION: Lidocaine-remifentanil-propofol is superior to lidocaine-remifentanil-thiopental for tracheal intubation without muscle relaxants. However, it induces more hypotension and bradycardia.     

Sevoflurane with remifentanil allows rapid tracheal intubation without neuromuscular blocking agents

PURPOSE: After inhalational induction with sevoflurane, we compared the effects of adding remifentanil 1 microg x kg(-1) or remifentanil 2 microg x kg(-1) on conditions for tracheal intubation without neuromuscular blocking agents. METHODS: Before anesthetic induction, all patients were given 0.2 mg of glycopyrrolate iv to counteract the bradycardic effects of remifentanil. Two minutes after inhalational induction with 8% sevoflurane and 50% nitrous oxide, 56 female patients with normal airways scheduled for gynecologic surgery were randomized to receive remifentanil 1 or 2 microg x kg(-1) in a double-blind fashion. One minute later, laryngoscopy was initiated for tracheal intubation. Conditions for tracheal intubation and hemodynamic response to tracheal intubation were assessed. RESULTS: Tracheal intubation was successful in all patients. The incidence of post-intubation coughing was lower in the remifentanil 2 microg x kg(-1) group compared to remifentanil 1 microg x kg(-1) group (11% vs 39%, P <0.02). Optimal intubation conditions were also higher in the remifentanil 2 microg x kg(-1) group at 89% vs 54% (P <0.01). However, the higher dose of remifentanil also resulted in a greater decrease in mean arterial pressure (P <0.05). CONCLUSIONS: The addition of remifentanil after sevoflurane induction allows for rapid tracheal intubation without neuromuscular blocking agents. The higher dose of remifentanil results in improved conditions for tracheal intubation but also caused a greater decrease in mean arterial pressure. Tracheal intubation using sevoflurane and remifentanil may be an alternative to traditional tracheal intubation with neuromuscular blocking agents.     

Reducing the haemodynamic responses to laryngoscopy and intubation

The effects of alfentanil and fentanyl on controlling the haemodynamic responses to laryngoscopy and intubation have been compared. Five groups of ten patients were studied. Induction was with thiopentone 4 mg/kg. Thirty seconds later group 1 received 1 ml/20 kg saline, group 2 received 15 micrograms/kg alfentanil, group 3 received 30 micrograms/kg alfentanil and group 4 received 5 micrograms/kg fentanyl one minute before induction. Suxamethonium was given 60 seconds after induction and intubation of the trachea was performed 150 seconds after the start of induction. Heart rate and mean arterial pressure were recorded every minute throughout and compared with pre-induction control values. Control patients (group 1) showed significant increases associated with tracheal intubation in all haemodynamic variables. No increases were noted in groups receiving 30 micrograms/kg alfentanil or 5 micrograms/kg fentanyl. The heart rate, but not blood pressure, increased with intubation after 15 micrograms/kg alfentanil. The mean time to movement in 50% of the control patients was 7 minutes. In those given 15 and 30 micrograms/kg alfentanil it was 11 and 12 minutes respectively. In those given 5 micrograms/kg fentanyl it was greater than 15 minutes. Alfentanil is shown to reduce the cardiovascular responses to laryngoscopy and intubation and the effect appears to have a shorter duration than that of fentanyl.     

The effect of mivacurium pretreatment on intra-ocular pressure changes induced by suxamethonium

Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied in a double-blind, randomised, placebo-controlled study evaluating the efficacy of mivacurium pretreatment in attenuating the rise in intra-ocular pressure in response to suxamethonium administration, laryngoscopy and intubation. The patients were randomly allocated to receive either mivacurium 0.02 mg.kg⁻¹ or normal saline as pretreatment 3 min before a rapid sequence induction technique using alfentanil, propofol and suxamethonium. Suxamethonium induced a significant increase in intra-ocular pressure in the control group but not in the mivacurium pretreatment group (mean (SEM) increase = 3.5 (1.2) mmHg vs. 0.4 (0.8) mmHg, p < 0.05). There was a decrease in intra-ocular pressure in both groups after laryngoscopy and intubation with no significant difference between the two groups. These results show that mivacurium pretreatment is effective in preventing the increase in intra-ocular pressure after suxamethonium administration.     

Evaluation of remifentanil for control of haemodynamic response to tracheal intubation

We have studied the effect of three bolus doses of remifentanil on the haemodynamic response to laryngoscopy and tracheal intubation. Using a double-blind design, 80 ASA 1 or 2 patients presenting for elective surgery received saline placebo or remifentanil 0.25, 0.5 or 1.0 microgram.kg-1 by random allocation. Anaesthesia was induced with thiopentone 5-7 mg.kg-1 and followed immediately by the study medication given as a bolus over 30s. Muscle relaxation was provided with rocuronium 0.75 mg.kg-1. The patients' tracheas were intubated under direct laryngoscopy 1 min later. Noninvasive arterial blood pressure and heart rate were recorded immediately before induction of anaesthesia and then at intervals until 5 min after tracheal intubation. There was a significant increase in heart rate (p < 0.01) and systolic arterial pressure (p < 0.01) in all groups after tracheal intubation. However, this was short-lived and of a smaller magnitude in the remifentanil 1 microgram.kg-1 group in which the increase was significantly lower than in the control group (p < 0.01).     

Partial attenuation of hemodynamic responses to rapid sequence induction and intubation with labetalol

The effectiveness of labetalol (a combination nonselective beta and alpha-1-adrenergic receptor antagonist) in modifying hemodynamic responses associated with rapid sequence induction and tracheal intubation was evaluated. In a double-blind study, 24 ASA physical status I or II male patients scheduled for elective surgery were given either IV labetalol, 0.25 mg/kg (n = 8) or 0.75 mg/kg (n = 8), or a saline placebo (n = 8). Five minutes later, patients were given oxygen by mask and IV vecuronium, 0.01 mglkg. Ten minutes after giving labetalol or placebo, cricoid pressure was applied and anesthesia was induced with IV sodium thiopental (4 mg/kg) and succinylcholine (1.5 mg/kg) 1 minute prior to intubation. The mean duration of laryngoscopy was 17 ± 3 seconds. Prior to induction, the 0.25 mg/kg and 0.75 mg/kg) doses of labetalol significantly (p < 0.05) reduced mean arterial pressure by 4.4 ± 1.9 and by 8.6 ± 2.0 mmHg, respectively, but did not significantly alter heart rate or cardiac output. The 0.75 mg/kg) dose of labetalol also significantly (p < 0.05) decreased total peripheral resistance by 10.1 ± 3.0%. Within 30 seconds after intubation, patients in all three groups exhibited increases in heart rate, mean arterial pressure, total peripheral resistance, and rate pressure product and a decrease in stroke volume. However, patients in the 0.25 and 0.75 mg/kg) labetalol groups, compared to those in the placebo group, had significantly lower increases in peak heart rate (33 ± 2 and 27 ± 3 vs. 44 ± 7 beats/minute), peak mean arterial pressure (38 ± 6 and 38 ± 7 vs. 58 ± 7 mmHg), and peak rate pressure product (7,726 ± 260 and 7,215 ± 300 vs. 14,023 ± 250 units). The results show that these doses of labetalol significantly blunt, but do not completely block, autonomic responses to rapid sequence induction and intubation.     

Attenuation of hypertensive response to tracheal intubation with nitroglycerin.

STUDY OBJECTIVE: To evaluate the efficacy and safety of intravenous (IV) nitroglycerin in attenuating the hypertensive response to laryngoscopy and intubation as a new application of the drug. DESIGN: Controlled, randomized, double-blind study. SETTING: University hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery were divided into three groups of ten patients each. INTERVENTIONS: Anesthesia was induced with thiopental sodium 5 mg/kg i.v., and tracheal intubation was facilitated with vecuronium 0.2 mg/kg i.v. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Either 1.5 micrograms/kg of nitroglycerin, 2.5 micrograms/kg of nitroglycerin, or saline (control) was administered IV simultaneously with the start of laryngoscopy (lasting 30 seconds), which was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in nitroglycerin-treated patients compared with those in the control group (p < 0.05). CONCLUSION: A single, rapid IV dose of nitroglycerin is a simple, practical, effective, and safe method to attenuate the hypertensive response to laryngoscopy and tracheal intubation.     

Retrograde intubation in patients undergoing open heart surgery

Cardiovascular changes during difficult intubation were studied in 25 patients undergoing open heart surgery. The study was divided into two phases. Phase A from the first laryngoscopy to the fourth unsuccessful one; Phase B from a stabilization period until after retrograde intubation was performed. During phase A, heart rate (HR) increased significantly from 75 +/- 6.5 beats/min before laryngoscopy to 95 +/- 8.5 (p less than 0.05) after the last laryngoscopy. Mean arterial pressure (MAP) also increased from 82.5 +/- 4.75 mmHg to 105 +/- 5.15 (p less than 0.005) after the last laryngoscopy. Cardiac index (CI) decreased from 2.9 +/- 0.3 L . min-1 . m-2 before to 2.55 +/-0.2 after the last laryngoscopy. Pulmonary capillary wedge pressure (PCWP) increased from 10.5 +/- 1 mmHg before to 19.25 +/- 1.5 (p less than 0.01) after the last laryngoscopy. No statistically significant changes in HR, MAP, CI, and PCWP occurred before and after intubation during Phase B. Three patients had elevated ST segments during Phase A which responded to IV nitroglycerin and propranolol. None was detected during Phase B. There were more lacerated lips and teeth damaged during Phase A. One patient developed a small peritracheal haematoma after the retrograde intubation, for which no treatment was required. This technique is safe and produces minimal cardiovascular changes for difficult intubation in patients undergoing open heart surgery.     

Partial attenuation of the cardiovascular responses to tracheal intubation with oral nisoldipine.

STUDY OBJECTIVE: To evaluate the efficacy and safety of nisoldipine given orally in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Induction of anesthesia for elective surgery at a university hospital. PATIENTS: Thirty normotensive patients (ASA physical status I) undergoing elective surgery were assigned to one of three groups; placebo, nisoldipine 5 mg, or nisoldipine 10 mg. Each group consisted of ten patients. INTERVENTIONS: Either 5 mg of nisoldipine, 10 mg of nisoldipine, or a placebo was administered orally 2 hours before induction of anesthesia. Anesthesia was induced with thiopental sodium 5 mg/kg intravenously, and tracheal intubation was facilitated with vecuronium 0.2 mg/kg. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 seconds was attempted 2 minutes after administration of thiopental sodium and vecuronium. MEASUREMENTS AND MAIN RESULTS: Patients receiving the placebo showed a significant increase in mean arterial pressure associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in patients receiving nisoldipine 10 mg compared with patients receiving the placebo (p less than 0.05). CONCLUSIONS: Oral administration of nisoldipine before induction of anesthesia is a simple, practical, and safe method for attenuating pressor response to laryngoscopy and tracheal intubation.     

A comparison of laryngeal mask airway with tracheal tube for intra-ocular ophthalmic surgery

The use of the laryngeal mask was compared with tracheal intubation in 30 patients who underwent intra-ocular ophthalmic surgery and who received intravenous anaesthesia with propofol. Changes in intra-ocular pressure, heart rate and mean arterial pressure after the insertion of the laryngeal mask airway or the tracheal tube were not significantly different. However, at the end of the procedure, a significantly higher percentage of patients with a tracheal tube coughed, reacted to head movement and suffered breath-holding. In addition, significantly more patients in this group complained of a sore throat (p less than 0.05). During intravenous propofol anaesthesia, the laryngeal mask airway does not offer any advantage over tracheal intubation in the control of intra-ocular pressure for intra-ocular ophthalmic surgery. However, there were fewer complications immediately following surgery in the laryngeal mask group.     

Hemodynamic responses to tracheal intubation with laryngoscope versus lightwand intubating device (Trachlight) in adults with normal airway

Lightwand devices are effective and safe as an aid to tracheal intubation. Theoretically, avoiding direct-vision laryngoscopy could allow for less stimulation by intubation than the conventional laryngoscopic procedure. We designed this prospective randomized study to assess the cardiovascular changes after either lightwand or direct laryngoscopic tracheal intubation in adult patients anesthetized with sevoflurane. Sixty healthy adult patients with normal airways were randomly assigned to one of three groups according to intubating procedure under sevoflurane/nitrous oxide anesthesia (fraction of inspired oxygen = 0.33) (n = 20 each). The lightwand group received tracheal intubation with Trachlight, the laryngoscope-intubation group received tracheal intubation with a direct-vision laryngoscope (Macintosh blade), and the laryngoscopy-alone group received the laryngoscope alone. Heart rate and systolic blood pressure were recorded continuously for 5 min after tracheal intubation or laryngoscopy with enough time to intubate. All procedures were successful on the first attempt. The maximum heart rate and systolic blood pressure values obtained after intubation with Trachlight (114 +/- 20 bpm and 143 +/- 30 mm Hg, respectively) did not differ from those with the Macintosh laryngoscope (114 +/- 20 bpm and 138 +/- 23 mm Hg), but they were significantly larger than those in the laryngoscopy-alone group (94 +/- 19 bpm and 112 +/- 21 mm Hg) (P < 0.05). Direct stimulation of the trachea appears to be a major cause of the hemodynamic changes associated with tracheal intubation. IMPLICATIONS: The magnitude of hemodynamic changes associated with tracheal intubation with the Trachlight is almost the same as that which occurs with the direct laryngoscope. Hemodynamic changes are likely to occur because of direct tracheal irritation rather than direct stimulation of the larynx.     

Using the intubating laryngeal mask airway for ventilation and endotracheal intubation in anesthetized and unparalyzed acromegalic patients

Airway management may be difficult in acromegalic patients. The purpose of the study was to evaluate the intubating laryngeal mask airway (ILMA) as a primary tool for ventilation and intubation in acromegalic patients. Twenty-three consenting consecutive adult acromegalic patients presenting for transsphenoidal resection of pituitary adenoma were enrolled in the study. Anesthesia was induced using propofol (1.5 mg/kg followed by 0.5-mg/kg increments); the ILMA was inserted when the bispectral index fell below 50. The ILMA was successful as a primary airway for oxygenation and ventilation at the first attempt for 21 (91%) patients, while 2 (9%) patients required a second attempt. Patient movement was noticed in five (21.7%) of the patients during ILMA insertion. An attempt at tracheal intubation through the ILMA was performed following administration of a mean 395 +/- 168-mg dose of propofol. Overall success rates for tracheal intubation were 82% (19 patients). The first-attempt success rate for tracheal intubation was 52.6% (10 patients), second- and third-attempt success rates were 42.1% (8 patients) and 5.3% (1 patient), respectively. Coughing or movement during intubation was observed in 12 (63.2%) of the patients. Direct laryngoscopy permitted intubation in three cases and blind intubation using a bougie in the fourth case. ILMA can be used as a primary airway for oxygenation in acromegalic patients (manual bag ventilation), but the rate of failed blind intubation through the ILMA precludes its use as a first choice for elective airway management.