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PubMed1991

Effects of pindolol on the cardiovascular response to tracheal intubation.

Laryngoscopy and tracheal intubation often cause hypertension, tachycardia and arrhythmias, which may be exaggerated during rapid-sequence induction of anaesthesia. We have studied the efficacy of pindolol in attenuating the cardiovascular responses to laryngoscopy and intubation in patients receiving pindolol 2 micrograms kg-1 or 4 micrograms kg-1 3 min before induction of anaesthesia in a double-blind design. The data were compared with those in a control group receiving saline. Each group consisted of 10 patients undergoing elective surgery. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. Patients receiving saline showed a significant increase in mean arterial pressure and heart rate associated with tracheal intubation. These increases after tracheal intubation were reduced in pindolol 4 micrograms kg-1 treated patients compared with those in the control group (P less than 0.05). Pindolol 2 micrograms kg-1 attenuated tachycardia in response to intubation but did not affect hypertension. These data suggest that a bolus injection of pindolol 4 micrograms kg-1 is a simple, practical and effective method for attenuating cardiovascular responses to laryngoscopy and tracheal intubation.

Adult↗
PubMed1996

Comparison of nicardipine, diltiazem and verapamil for controlling the cardiovascular responses to tracheal intubation.

We have compared the efficacy of three calcium channel blockers, nicardipine, diltiazem and verapamil, in attenuating the cardiovascular responses to laryngoscopy and intubation in 60 normotensive patients (ASA I) undergoing rapid sequence induction of anaesthesia with thiopentone and fentanyl. We also examined whether or not these blockers inhibited catecholamine release induced by intubation. The patients were allocated to one of four groups (n = 15 for each): saline (control), nicardipine 30 micrograms kg-1, diltiazem 0.2 mg kg-1 or verapamil 0.1 mg kg-1. Verapamil and the three other drugs were administered 45 s and 60 s before the start of direct laryngoscopy, respectively, in a double-dummy design. Anaesthesia was induced with thiopentone 4 mg kg-1 i.v. and fentanyl 2 micrograms kg-1 i.v. Tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% isoflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 s was attempted 2 min after administration of thiopentone and vecuronium. Patients receiving saline exhibited significant increases in systolic and diastolic arterial pressures (AP), heart rate (HR) and plasma concentrations of catecholamines associated with tracheal intubation. The increase in AP was attenuated in patients treated with any calcium channel blocker. The greatest effect was elicited by verapamil, which attenuated the increase in HR, although nicardipine seemed to enhance tachycardia. All three drugs failed to suppress the increase in plasma catecholamine concentrations in response to tracheal intubation. These findings suggest that bolus injection of verapamil 0.1 mg kg-1 was a more effective method of controlling hypertension and tachycardia associated with intubation than diltiazem 0.2 mg kg-1 or nicardipine 30 micrograms kg-1, and that these prophylactic effects were not caused by inhibition of the catecholamine response.

Adult↗
PubMed2001

Comparison of effects of remifentanil and alfentanil on cardiovascular response to tracheal intubation in hypertensive patients.

In a randomized double-blind study, we compared the effect of remifentanil and alfentanil on the cardiovascular response to laryngoscopy and tracheal intubation in patients on long-term treatment for hypertension. Forty ASA II-III patients were allocated to receive (i) remifentanil 0.5 microg kg(-1) followed by an infusion of 0.1 microg kg min(-1) or (ii) alfentanil 10 microg kg(-1) followed by an infusion of saline; all patients received glycopyrrolate 200 microg before the study drug. Anaesthesia was induced with propofol and rocuronium and maintained with 1% isoflurane and 66% nitrous oxide in oxygen. Laryngoscopy and tracheal intubation were performed after establishment of neuromuscular block. Arterial pressure and heart rate (HR) were measured non-invasively at 1 min intervals from 3 min before induction until 5 min after intubation. Systolic (SAP), diastolic and mean arterial pressure decreased significantly after induction in both groups (P<0.05). Maximum increases in mean SAP after laryngoscopy and intubation were 35 and 41 mm Hg in the remifentanil and alfentanil groups, respectively. After intubation, arterial pressure did not increase above baseline values in either group. HR remained stable after induction of anaesthesia, but increased above baseline values after intubation. Mean maximum HR was 87 beats min(-1) for the remifentanil group (12 beats min(-1) above baseline; P=0.065) and 89 beats min(-1) for the alfentanil group (15 beats min(-1) above baseline; P<0.05). There were no significant differences between groups in HR or arterial pressure at any time. There were no incidences of bradycardia. Seven patients in the remifentanil group and four in the alfentanil group received ephedrine for hypotension (i.e. SAP<100 mm Hg).

Adult↗
PubMed2002

Esmolol prevents movement and attenuates the BIS response to orotracheal intubation.

BACKGROUND: Beta-adrenergic agonists enhance behavioural and electroencephalographic arousal reactions. We explored whether adding esmolol, a short-acting beta(1)-adrenoceptor antagonist, to propofol anaesthesia modified the bispectral index (BIS) during induction of anaesthesia and orotracheal intubation. METHODS: Fifty patients were randomly allocated, in a double-blind fashion, to receive esmolol 1 mg kg(-1) followed by 250 micro g kg(-1) min(-1) or saline (control). Esmolol or saline was started 6 min after a target-controlled infusion (TCI) of propofol (effect-site concentration 4 micro g ml(-1)). After loss of consciousness, and before administration of vecuronium 0.1 mg kg(-1), a tourniquet was applied to one arm and inflated to 150 mm Hg greater than systolic pressure. Eleven minutes after the TCI began, the trachea was intubated; gross movement within the first min after orotracheal intubation was recorded. BIS was recorded at 10-s intervals. Mean arterial pressure (MAP) and heart rate were measured non-invasively every min. RESULTS: There were no intergroup differences in BIS, heart rate or MAP before laryngoscopy. BIS increased significantly after orotracheal intubation (compared with the pre-laryngoscopy values) in the control group only, with a maximum increase of 40 (SD 18)% vs 8 (11)% in the esmolol group (P<0.01). Maximum changes in heart rate [45 (19)% vs 23 (14)%] and MAP [62 (24)% vs 45 (23)%] with orotracheal intubation were also significantly greater in the control group than in the esmolol group. More patients in the control than in the esmolol group moved after orotracheal intubation (23 vs 12, P<0.01). CONCLUSION: Esmolol not only attenuated haemodynamic and somatic responses to laryngoscopy and orotracheal intubation, but also prevented BIS arousal reactions in patients anaesthetized with propofol.

Adjuvants, Anesthesia↗
PubMed2006

Correlation and agreement between bispectral index and state entropy of the electroencephalogram during propofol anaesthesia.

BACKGROUND: Bispectral index (BIS) and state entropy (SE) monitor hypnosis. We evaluated the correlation and the agreement between those parameters during propofol anaesthesia and laryngoscopy with and without muscle relaxation. METHODS: A total of 25 patients were anaesthetized with propofol. At steady state (SS: BIS 40-50), they randomly received rocuronium (R) or saline (S); 3 min thereafter, a 20 s laryngoscopy was performed. Correlation (regression analysis) and agreement (Bland-Altman analysis) were evaluated before induction (baseline), at loss of eyelash reflex (LER), at SS and during the first 3 min after laryngoscopy (L). RESULTS: The correlation coefficient r (95% CI), the mean difference (MD) (95% CI), and the limits of agreement [lower-upper limits of 95% CI of MD (sd 1.96)] between BIS and SE were as follows. Overall recordings: 0.87 (0.83 to 0.90), 2.5 (1.2 to 3.0), and [-19.5 to 24.6]; Baseline: 0.45 (0.06 to 0.72), 7.6 (6.0 to 9.2), and [-2.7 to 17.9]; LER: 0.74 (0.47 to 0.88), 8.3 (3.5 to 13.2), and [-22.6 to 39.3]; SS, all patients: 0.41 (0.14 to 0.63), 2.0 (-0.5 to 4.6), and [-19.0 to 23.3]; SS, Group S: 0.36 (-0.07 to 0.68), 1.9 (-2.5 to 6.3), and [-25.0 to 28.8]; SS, Group R: 0.63 (0.32 to 0.82), 0.2 (-2.0 to 2.3), and [-14.0 to 14.4]; L, all patients: 0.49 (0.32 to 0.63), 0.7 (-1.6 to 3.0), and [-25.6 to 27.1]; L, Group S: 0.41 (0.13 to 0.63), 2.3 (-2.4 to 7.1), and [-36.7 to 41.3]; L, Group R: 0.72 (0.56 to 0.83), -0.6 (-2.2 to 1.0), and [-14.3 to 13.1]. The correlation was good except for SS in Group S. The MD was significantly different from 0 for overall recordings, during baseline and LER, but not for the other conditions. The agreement was poor except for baseline, and SS and L in Group R. CONCLUSIONS: BIS and SE are globally well correlated. In contrast, agreement is poor as differences of more than 20 units are frequently observed, except for awake and paralysed patients.

Adult↗
PubMed2000

The effect of remifentanil on the bispectral index change and hemodynamic responses after orotracheal intubation.

UNLABELLED: In order to examine whether changes in the bispectral index (BIS) may be an adequate monitor for the analgesic component of anesthesia, we evaluated the effect of remifentanil on the BIS change and hemodynamic responses to laryngoscopy and tracheal intubation. Fifty ASA physical status I patients were randomly assigned, in a double-blinded fashion, to one of five groups (n = 10/group) according to the remifentanil target effect compartment site concentration (0, 2, 4, 8, or 16 ng/mL). The target-controlled infusion (TCI) of remifentanil was initiated 3 min after the TCI of propofol that was maintained at the effect-site concentration of 4 microg/mL throughout the study. After the loss of consciousness and before the administration of vecuronium 0.1 mg/kg, a tourniquet was applied to one arm and inflated above the systolic blood pressure in order to detect any gross movement within the first minute after tracheal intubation, which was performed 3 min after remifentanil TCI began. A BIS value was generated every 10 s. Arterial blood pressure and heart rate (HR) were measured every minute, noninvasively. Measures of mean arterial pressure (MAP), HR, and BIS were obtained before the induction, before the start of remifentanil TCI, before laryngoscopy, and 5 min after intubation. The relationships between remifentanil effect-site concentrations and BIS change or hemodynamic responses (changes in MAP and HR) to intubation were determined by logarithmic regression. BIS values were not affected by remifentanil before laryngoscopy. During this period, MAP and HR decreased significantly (P < 0.01) in the remifentanil 8 and 16 ng/mL groups. Changes in BIS, MAP, and HR were negatively correlated with remifentanil effect-site concentration (P < 0.0001). The number of movers in the remifentanil 0-, 2-, 4-, 8-, and 16-ng/mL groups was, respectively, 10, 9, 7, 1, and 0. Hypotensive episodes (MAP < 60 mm Hg) were noted in 1, 2, and 5 patients in the remifentanil 4-, 8-, and 16-ng/mL groups, respectively. We conclude that the addition of remifentanil to propofol affects BIS only when a painful stimulus is applied. Moreover, remifentanil attenuated or abolished increases in BIS and MAP after tracheal intubation in a comparable dose-dependent fashion. IMPLICATIONS: Bispectral index change is as sensitive as hemodynamic responses after a painful stimulus for detecting deficits in the analgesic component of anesthesia. It may, therefore, be a useful monitor of the depth of anesthesia in patients who are incapable of HR and MAP responses to noxious stimuli because of medications or cardiovascular disease.

Adolescent↗
PubMed1995

Clinical trial of a new lightwand device (Trachlight) to intubate the trachea.

BACKGROUND: Transillumination of the soft tissue of the neck using a lighted stylet (lightwand) is an effective and safe intubating technique. A newly designed lightwand (Trachlight) incorporates modifications to improve the brightness of the light source as well as flexibility. The goal of this study was to determine the effectiveness and safety of this device in intubating the trachea of elective surgical patients. METHODS: Healthy surgical patients were studied. Patients with known or potential problems with intubation were excluded. During general anesthesia, the tracheas were intubated randomly using either the Trachlight or the laryngoscope. Failure to intubate was defined as lack of successful intubation after three attempts. The duration of each attempt was recorded as the time from insertion of the device into the oropharynx to the time of its removal. The total time to intubation (TTI), an overall measure of the ease of intubation, was defined as the sum of the durations of all (as many as three) intubation attempts. Complications, such as mucosal bleeding, lacerations, dental injury, and sore throat, were recorded. RESULTS: Nine hundred fifty patients (479 in the Trachlight group and 471 in the laryngoscope group) were studied. There was a 1% failure rate with the Trachlight, and 92% of intubations were successful on the first attempt, compared with a 3% failure rate and an 89% success rate on the first attempt with the laryngoscope (P not significant). All failures were followed by successful intubation using the alternate device. The TTI was significantly less with the Trachlight compared with the laryngoscope (15.7 +/- 10.8 vs. 19.6 +/- 23.7 s). For laryngoscopic intubation, the TTI was longer for patients with limited mandibular protrusion and mentohyoid distance, with a larger circumference of the neck, and with a high classification according to Mallampatti et al. However, there was no relation between the TTI and any of the airway parameters for Trachlight. There were significantly fewer traumatic events in the Trachlight group than in the laryngoscope group (10 vs. 37). More patients complained of sore throat in the laryngoscope group than in the Trachlight group (25.3% vs. 17.1%). CONCLUSIONS: In contrast to laryngoscopy, the ease of intubation using the Trachlight does not appear to be influenced by anatomic variations of the upper airway. Intubation occasionally failed with the Trachlight but in all cases was resolved with direct laryngoscopy. The failures of direct laryngoscopy were resolved with Trachlight. Thus the combined technique was 100% successful in intubating the tracheas of all patients.

Adult↗
PubMed1997

Comparison of the Bullard and Macintosh laryngoscopes for endotracheal intubation of patients with a potential cervical spine injury.

BACKGROUND: In the emergency trauma situation, in-line stabilization (ILS) of the cervical spine is used to reduce head and neck extension during laryngoscopy. The Bullard laryngoscope may result in less cervical spine movement than the Macintosh laryngoscope. The aim of this study was to compare cervical spine extension (measured radiographically) and time to intubation with the Bullard and Macintosh laryngoscopes during a simulated emergency with cervical spine precautions taken. METHODS: Twenty-nine patients requiring general anesthesia and endotracheal intubation were studied. Patients were placed on a rigid board and anesthesia was induced. Laryngoscopy was performed on four occasions: with the Bullard and Macintosh laryngoscopes both with and without manual ILS. Cricoid pressure was applied with ILS. To determine cervical spine extension, radiographs were exposed before and during laryngoscopy. Times to intubation and grade view of the larynx were also compared. RESULTS: Cervical spine extension (occiput-C5) was greatest with the Macintosh laryngoscope (25.9 degrees +/- 2.8 degrees). Extension was reduced when using the Macintosh laryngoscope with ILS (12.9 +/- 2.1 degrees) and the Bullard laryngoscope without stabilization (12.6 +/- 1.8 degrees; P < 0.05). Times to intubation were similar for the Macintosh laryngoscope with ILS (20.3 +/- 12.8 s) and for the Bullard without ILS (25.6 +/- 10.4 s). Manual ILS with the Bullard laryngoscope results in further reduction in cervical spine extension (5.6 +/- 1.5 degrees) but prolongs time to intubation (40.3 +/- 19.5 s; P < 0.05). CONCLUSIONS: Cervical spine extension and time to intubation are similar for the Macintosh laryngoscope with ILS and the Bullard laryngoscope without ILS. However, time to intubation is significantly prolonged when the Bullard laryngoscope is used in a simulated emergency with cervical spine precautions taken. This suggests that the Bullard laryngoscope may be a useful adjunct to intubation of patients with potential cervical spine injury when time to intubation is not critical.

Adult↗
PubMed1989

The pressor response and laryngeal mask insertion. A comparison with tracheal intubation.

The pressor response associated with laryngoscopy and tracheal intubation may be harmful to certain patients. The laryngeal mask airway avoids the need for laryngoscopy and allows positive pressure ventilation of the lungs in appropriate patients. This study compared the pressor response of tracheal intubation with that of mask insertion in two groups of 24 and 23 healthy patients respectively. All patients were anaesthetised with thiopentone, nitrous oxide, enflurane and paralysed with atracurium. We have shown a similar, but attenuated pattern of response associated with mask insertion in comparison with laryngoscopy and intubation; significant differences between the groups were evident in arterial diastolic blood pressure immediately after insertion and again 2 minutes later. Use of the laryngeal mask may therefore offer some limited advantages over tracheal intubation in the anaesthetic management of patients where the avoidance of the pressor response is of particular concern.

Adult↗
PubMed1990

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.

Blood Pressure↗
PubMed1992

Effects of nicardipine on the circulatory responses to tracheal intubation in normotensive and hypertensive patients.

This study was undertaken to examine the effects of nicardipine on circulatory responses to laryngoscopy and tracheal intubation in normotensive (n = 39) and hypertensive (n = 36) patients. Laryngoscopy and tracheal intubation were performed after induction of anaesthesia with thiamylal, followed by administration of intravenous saline or nicardipine 20 or 30 micrograms.kg-1 and suxamethonium. Blood pressure and heart rate were recorded, and rate-pressure product was calculated. Nicardipine 20 and 30 micrograms.kg-1 prevented the increase in mean arterial pressure after intubation in normotensive and hypertensive patients (p less than 0.01 compared with saline). The changes in heart rate after intubation were significantly greater in normotensive patients than in hypertensive patients when 20 or 30 micrograms.kg-1 of nicardipine was given (p less than 0.05 and p less than 0.01 respectively). Rate-pressure product increased significantly (p less than 0.01) after intubation in normotensive patients whether nicardipine was administered or not, but the increase was suppressed completely by nicardipine 20 or 30 micrograms.kg-1 in hypertensive patients. We conclude that nicardipine is effective in preventing the circulatory responses to laryngoscopy and tracheal intubation in hypertensive patients.

Adult↗
PubMed1992

Cardiovascular responses to insertion of the laryngeal mask.

We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced by insertion of a laryngeal mask. Anaesthesia was induced with thiopentone and maintained with enflurane and nitrous oxide in oxygen; vecuronium was used for muscle relaxation. Arterial pressure was measured with a Finapres monitor. The mean maximum increase in systolic arterial pressure after laryngoscopy and tracheal intubation was 51.3% compared with 22.9% for laryngeal mask insertion (p less than 0.01). Increases in maximum heart rate were similar, (26.6% v 25.7%) although heart rate remained elevated for longer after tracheal intubation. We conclude that insertion of the laryngeal mask airway is accompanied by smaller cardiovascular responses than those after laryngoscopy and intubation and that its use may be indicated in those patients in whom a marked pressor response would be deleterious.

Adult↗
PubMed1991

Isoflurane in nitrous oxide and oxygen increases plasma concentrations of noradrenaline but attenuates the pressor response to intubation.

The haemodynamic response to laryngoscopy and intubation was evaluated in 52 ASA I patients anaesthetized with thiopentone 4-6 mg.kg-1. Vecuronium 0.1 mg.kg-1, followed by 3 min mask ventilation with nitrous oxide in oxygen with (isoflurane group) or without (control group) 3% inspired isoflurane preceded tracheal intubation. In 21 of 52 patients, concentrations of noradrenaline (NA), adrenaline and 3,4-dihydroxyphenylethyleneglycol (DHPG) were measured from central venous plasma. During the 3-min ventilation, in the isoflurane group, heart rate increased by 22% but remained stable in the control group. A marked pressor response to laryngoscopy and intubation was seen in the control but not in the isoflurane group. During the 3-min ventilation, the plasma concentration of NA was doubled in the isoflurane group and increased by 49% in the control group (P less than 0.05). The concentration of DHPG also increased in the isoflurane group. Peripheral skin temperature increased similarly after 3 min ventilation in both groups. After intubation, it was significantly higher in the isoflurane than in the control group (P less than 0.05). In conclusion, compared to nitrous oxide in oxygen, ventilation with isoflurane in nitrous oxide in oxygen causes a sympathetic activation combined with an increase in heart rate and peripheral temperature while the pressor response to laryngoscopy and intubation is attenuated.

Adult↗
PubMed1992

Timing of peak pressor response following endotracheal intubation.

The study was designed to measure the timing of the peak cardiovascular response following laryngoscopy and endotracheal intubation. Thirty patients ASA 1 or 2 were studied, with arterial pressure being continuously monitored using the Ohmeda 2300 Finapres. Patients were randomised to receive either propofol 2.5 mg.kg-1 (Group A) or thiopentone 4.5 mg.kg-1 (Group B). The mean time to complete laryngoscopy and intubation was 26 s in Group A and 20 s in Group B. The peak response occurred on average 31 s after the start of the stimulus in Group A and after 32 s in Group B. In 8 out of the 30 cases the peak response occurred during the period of stimulation. Systolic pressure fell on average by 2.6 kPa (20 mmHg) (range 0 to 5.9 (45 mmHg)) from its peak value to the value measured at the 1-min time mark in the propofol group, and by 2.3 kPa (17 mmHg) (range 0.4 (3 mmHg) to 3.8 (29 mmHg)) in the thiopentone group. We conclude that the use of slow arm-cuff-based arterial pressure measurement techniques may miss important hypertensive episodes during laryngoscopy and endotracheal intubation. The effectiveness of agents in obtunding the pressor response may thus be misinterpreted.

Adolescent↗
PubMed1994

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

We conducted a placebo-controlled, randomized, and double-blinded study to evaluate the efficacy of manidipine given orally in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation. Thirty normotensive patients (ASA physical status 1) undergoing elective surgery were allocated to one of three groups (n = 10 for each); placebo, 5 mg manidipine, and 10 mg manidipine groups. These tablets were orally administered 3 h before induction of anaesthesia. Anaesthesia was induced with thiopentone 5 mg.kg-1 iv, and tracheal intubation was facilitated with vecuronium 0.2 mg.kg-1. Laryngoscopy lasting 30 sec was attempted 2 min after induction of anaesthesia. Patients receiving placebo showed a significant increase in systolic and diastolic blood pressure associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in patients receiving manidipine 10 mg compared with patients receiving placebo or manidipine 5 mg (P < 0.05). Oral administration of manidipine 10 mg before induction of anaesthesia is a simple and effective method for attenuating pressor response to laryngoscopy and tracheal intubation. We stressed that the potential beneficial effect of a reduced haemodynamic reaction to intubation might be obtained at the expense of hypotension later on.

Administration, Oral↗
PubMed2006

Evaluation of the new Viewmax laryngoscope in a simulated difficult airway.

BACKGROUND: In this study, we evaluated the learning curve and performance of the Viewmax laryngoscope during simulated difficult laryngoscopy in an intubation manikin (Laerdal Airway Management Trainer). METHODS: To determine the learning curve, 25 anaesthesiologists without previous experience with the Viewmax laryngoscope performed 10 successive intubations in an intubation manikin with a normal airway. Time to intubation and failed intubation attempts were recorded. Another manikin was modified to enable comparison of the Viewmax laryngoscope with Macintosh and McCoy laryngoscopes. The time to intubation, number of failed intubation attempts, modified Cormack and Lehane (MCL) laryngeal view grading, percentage of glottic opening (POGO score), use of gum elastic bougie and subjective rating of degree of difficulty were recorded. RESULTS: The learning curve for the Viewmax laryngoscope showed a progressive decrease in time to successful intubation and reached a plateau at the sixth attempt. In simulated difficult laryngoscopy, the Viewmax laryngoscope demonstrated significantly better laryngeal view than the Macintosh and McCoy laryngoscopes in terms of MCL grading (Macintosh, P = 0.01; McCoy, P < 0.01) and POGO score (Macintosh, P < 0.01; McCoy, P < 0.01). The time required for intubation in simulated difficult laryngoscopy for the Viewmax laryngoscope was significantly longer than that for the Macintosh (P = 0.02) and McCoy (P < 0.01) laryngoscopes. There was no significant difference in the degree of difficulty, number of failed intubations and use of gum elastic bougie. CONCLUSION: When compared with the Macintosh and McCoy laryngoscopes in a manikin, the Viewmax laryngoscope appears to improve the view of the larynx but requires a longer time for tracheal intubation.

Clinical Competence↗
PubMed2006

Randomized controlled trial comparing the laryngeal tube and the laryngeal mask in pediatric patients.

BACKGROUND: The laryngeal tube (LT) is a supraglottic ventilatory device used in adults. However, there is limited information about LT use in pediatric patients. This randomized controlled study compares LT with laryngeal mask (LMA) for airway management during spontaneous or assisted ventilation and during fiberoptic laryngoscopy in children. METHODS: Thirty children under 10-years old, ASA I-II, scheduled for minor general surgery, Mallampati score I-II, fasted and premedicated were included. Patients with upper respiratory infection, craniofacial malformation, intracranial hypertension, emergency surgery were excluded. The primary outcome measure was the proportion of patients in whom effective spontaneous or assisted ventilation [Vt > or = 4 ml.kg(-1), SpO2 > or = 95% with FiO2 0.4, P(E)CO2 < or = 7.2 kPa (55 mmHg)] was achieved after 3 min of LT or LMA cuff inflation. The secondary endpoint was the proportion of patients in whom fiberoptic laryngoscopy resulted in identification of the vocal cords. RESULTS: Eleven children with LMA and two children in LT group had adequate spontaneous or assisted ventilation after initial positioning (P < 0.01). After head extension or device repositioning 15 of 15 patients in LMA group had adequate ventilation compared with 11 of 15 patients in LT group (P < 0.05). The vocal cords could be observed with fiberoptic laryngoscopy in 11 LMA group patients compared with no patients in the LT group (P < 0.001). CONCLUSIONS: The LT is less effective than the LMA to allow adequate spontaneous or assisted ventilation and for fiberoptic evaluation of the airway in children under 10 years old.

Anesthesia, General↗
PubMed1996

Early diagnosis and stage classification of vocal cord abductor paralysis in patients with multiple system atrophy.

OBJECTIVES: Vocal cord abductor paralysis (VCAP) is a life threatening complication which may cause nocturnal sudden death in patients with multiple system atrophy. However, the early diagnosis of VCAP is often difficult to make on routine laryngoscopy performed during wakefulness, as stridor, which is the sole symptom of VCAP in the early stage, develops only during sleep. The aim was to investigate laryngeal dysfunction in patients with multiple system atrophy while awake and asleep. METHODS: Seven patients with multiple system atrophy with nocturnal stridor and five control patients were studied. Vocal cord movement was analysed by laryngoscopy while the patients were awake and also during sleep induced by intravenous diazepam. RESULTS: When awake, for the seven patients with multiple system atrophy normal movement of the vocal cords occurred in three, mild abduction restriction in three, and paradoxical movement in one. When asleep, however, all showed obvious paradoxical movement with high pitched inspiratory stridor. In controls, there were no differences in the vocal cord movement between wakefulness and sleep. From these findings, VCAP could be divided into four stages: stage 0 (normal) with normal vocal cord movement during both wakefulness and sleep, stage 1 (mild VCAP) with normal movement during wakefulness and paradoxical movement during sleep, stage 2 (moderately severe VCAP) with abduction restriction during wakefulness and paradoxical movement during sleep, and stage 3 (severe VCAP) with an almost midline position for the vocal cords during both wakefulness and sleep. CONCLUSIONS: Laryngoscopy during sleep can disclose subclinical VCAP, making an early diagnosis of VCAP in patients with multiple system atrophy. Stage 2 of VCAP seems to be a suitable stage for tracheostomy in patients with multiple system atrophy.

Aged↗