The importance of the laryngeal mask in the difficult intubation and early experience with the intubating laryngeal mask airway--ILMA--Fastrach

The conventional laryngeal mask airway ("Standard" laryngeal mask airway SLMA is of outstanding importance in the management of the difficult airway. The intubating laryngeal mask airway (ILMA, commercial name Fastrach) has become available recently. First results indicate that the excellent ventilation characteristics of SLMA are maintained, but in addition blind intubation is successful in more than 90% of patients with normal anatomy as well as with difficult intubation. PURPOSE: We present the use of ILMA, compare the potential of the two laryngeal mask types in difficult intubation by own results, present the results of a first symposium on the ILMA held at Jersey in December 1996, the role of the SLMA in difficult intubation as proposed by the American and the French Societies of Anaesthesiology, as well as an outlook on possible uses of the ILMA in the light of the available results. METHODS: The SLMA was prospectively used between 1992 and 1997 for 66 operations in 55 patients with difficult intubation (laryngoscopic view Cormack grade IV, n = 24; grade III, n = 35; grade < III, n = 7). 48 operations were performed after resection of a facial carcinoma, 14 on patients without carcinoma who could not be intubated conventionally, 5 on patients with periglottic pathology, and on 50 normals. The ILMA was used on 150 patients between 11/1996 and 11/1997, 106 had normal anatomy, 33 were difficult to intubate (Cormack grade IV, n = 12; grade III, n = 21), 24 had a reduced mouth opening of < or = 2.5 cm awake, 14 of these also were difficult to intubate. RESULTS: Ventilation was superior to a face mask (FM): (SLMA: ventilation not sufficient (SaO2 < 90% > 30 sec) with a FM in 22 operations compared to 5 with a SLMA; ILMA: ventilation not sufficient with a FM in 7 operations compared to 3 with an ILMA). Blind intubation through a SLMA had a success rate of 50% and 34% in 50 normals and in 32 operations with difficult intubation after a mean of 2.6 intubation attempts each. The success rate per intubation attempt for the SLMA was 22% in normals and 13% in difficult intubation. Through an ILMA, blind intubation was successful in 92% of normals, 5 of them with immobile spine, in 91% in patients with difficult intubation, and in 83% in patients with reduced mouth opening. The success rate per intubation attempt was 60% in normals, 46% in difficult intubation, and 46% in reduced mouth opening, with a success rate for the first intubation attempt of 57%. This compares favourably with results presented at the Jersey symposium in 554 patients. CONCLUSION: The ILMA maintains the superb ventilation potential of a SLMA in difficult intubation but doubles the success rate of blind intubation irrespective of anatomical difficulties, with a 50% success rate during the first intubation attempt. Possible uses of the ILMA may be in difficult intubation situations including immobile spine, in cannot ventilate--cannot intubate situations comparable to a SLMA with an improved chance of successful intubation, and perhaps as a device for ventilation and intubation for untrained people. The use of the ILMA can be trained during everyday practice. Expert assessment of successful endotracheal tube position is mandatory.     

The intubating laryngeal mask airway: an initial assessment of performance

A new prototype of the laryngeal mask airway (LMA), the intubating laryngeal mask airway (ILMA), was used to facilitate tracheal intubation in 100 fasted patients presenting for elective surgery. Alignment of the ILMA with the larynx was assessed fibreoptically before intubation without the investigator performing the intubation being aware of the view score. Ease of intubation correlated with the view obtained and with the degree of manipulation of the ILMA needed to achieve tracheal intubation. Intubation was successful in 93 patients. Of the seven intubation failures, five occurred in the first 20 patients. Conventional connection to the breathing system and ventilation of the lungs of the patients were possible throughout the intubation procedure.     

Evaluation of intubating conditions with rocuronium and either propofol or etomidate for rapid sequence induction

We have assessed the effect of two induction agents on tracheal intubating conditions after rocuronium 0.6 mg.kg-1 in unpremedicated patients undergoing simulated rapid sequence induction. Following pre-oxygenation, anaesthesia was induced with propofol up to 2.5 mg.kg-1 (n = 35) or etomidate 0.3 mg.kg-1 (n = 36), and further increments as required. After loss of verbal contact, cricoid pressure was applied and rocuronium was injected. Laryngoscopy was performed at 45 s and intubation attempted at 60 s after rocuronium had been given. Ninety-four per cent of patients in the propofol group had clinically acceptable (good or excellent) intubating conditions compared to only 75% in the etomidate group (p = 0.025). Owing to coughing, one patient in the etomidate group could not be intubated on the first attempt. A greater pressor response also followed intubation after induction with etomidate. We conclude that etomidate and rocuronium alone cannot be recommended for intubation at 60 s under rapid sequence induction conditions.     

A comparison of awake versus paralyzed tracheal intubation for infants with pyloric stenosis

This prospective, nonrandomized, observational study of 76 infants with pyloric stenosis was conducted at an academic children's hospital and compared awake versus paralyzed tracheal intubation in terms of successful first attempt rate, intubation time, heart rate (HR) and arterial hemoglobin oxygen saturation (SpO2) changes, and complications. Three groups were determined by intubation method: awake (A) with an oxygen-insufflating laryngoscope, after rapid-sequence induction (R), or after modified rapid-sequence induction (M) including ventilation through cricoid pressure. Successful first attempt intubation rate was 64% for Group A versus 87% for paralyzed Groups R and M (P = 0.028). Median intubation time was 63 s in Group A versus 34 s in Groups R and M (P = 0.004). Transient, mild decreases in mean HR and SpO2 and incidences of significant bradycardia and decreased SpO2 did not vary by group. Complications, including bronchial or esophageal intubation, emesis, and oropharyngeal trauma, were few. Senior anesthesiologists intervened in four tracheal intubations. We advocate anesthetized, paralyzed tracheal intubation because struggling with conscious infants takes longer, often requires multiple attempts, and prevents neither bradycardia nor decreased SpO2. After induction, additional mask ventilation with O2 confers no advantage over immediate tracheal intubation in preserving SpO2. Implications: In our children's hospital, awake tracheal intubation was not superior to anesthetized, paralyzed intubation in maintaining adequate oxygenation and heart rate or in reducing complications, and should be abandoned in favor of the latter technique for routine anesthetic management of otherwise healthy infants with pyloric stenosis.     

Diltiazem-lidocaine combination for the attenuation of cardiovascular responses to tracheal intubation in hypertensive patients

PURPOSE: Hypertensive patients are prone to haemodynamic changes after laryngoscopy and tracheal intubation. This study was undertaken to compare the efficacy of a combination of diltiazem and lidocaine with that of each drug alone for suppressing the cardiovascular responses to tracheal intubation. METHODS: Sixty hypertensive patients (ASA II), defined as systolic blood pressure > 160 mmHg and/or diastolic blood pressure > 95 mmHg (World Health Organization), undergoing elective surgery received, in a randomized, double-blind manner, 0.3 mg.kg-1 diltiazem, 1.5 mg.kg-1 lidocaine, or 0.3 mg.kg-1 diltiazem plus 1.5 mg.kg-1 lidocaine i.v. (n = 20 of each) before the initiation of laryngoscopy. Anaesthesia was induced with 5 mg.kg-1 thiopentone i.v., and tracheal intubation was facilitated with 2 mg.kg-1 succinylcholine i.v. after precurarization with 0.02 mg.kg-1 vecuronium i.v. Changes in heart rate (HR), mean arterial pressure (MAP) and rate-pressure product (RPP) were measured before and at immediate, 1, 2, 3, 5 and 10 min after tracheal intubation. RESULTS: The inhibitory effects of diltiazem-lidocaine combination on cardiovascular responses to tracheal intubation was greater than those of diltiazem or lidocaine as a sole medicine (RPP; 10,602 +/- 1448 (combination) vs 11,787 +/- 1345 (diltiazem), 15,428 +/- 1756 (lidocaine), mean +/- SD, P < 0.05). CONCLUSION: Prophylactic therapy with diltiazem-lidocaine combination is more effective than diltiazem or lidocaine alone for attenuating the cardiovascular changes associated with tracheal intubation in hypertensive patients.     

Directional-tip endotracheal tubes for blind nasotracheal intubation

OBJECTIVES: To compare initial success rates of blind nasotracheal intubation using directional-tip endotracheal tubes vs standard endotracheal tubes. METHODS: A prospective trial comparing directional-tip and standard endotracheal tubes during initial attempts at blind nasotracheal intubation (BNTI) at a university hospital ED. Using an alternating schedule, the directional-tip or standard tube was used for the first attempt at BNT1. An attempt was defined as beginning when the tube was placed through the nose into the posterior pharynx and ending when the patient was intubated or the tube was removed from the nares. After the intubation, the physician graded the difficulty of the technique (i.e., easy/routine, intermediate, difficult, or unable to intubate nasally). RESULTS: There were 49 patients entered over 5 months. Patient presentations for the intubations were trauma (45.8%), overdose (33.3%), respiratory/cardiac event (12.5%), seizure (2.1%), and other (6.3%). Intubation was successful on the first attempt in 18 of 21 patients (86%; 95% CI, 64% to 97%) for the directional-tip tube vs 16 of 28 patients (57%; 95% CI, 37% to 76%) for the standard tube (p = 0.03). The groups did not differ in age, sex, clinical presentation, or perceived difficulty of intubation. Only 1 patient could not be intubated nasally and was subsequently intubated orally. CONCLUSION: The use of directional-tip tubes may improve the success rate of the first attempt at BNTI.     

A systematic review on gender-specific suicide mortality in medical doctors

The effect of buprenorphine on the haemodynamic response to tracheal intubation was studied at two dose levels, 2.5 micrograms.kg-1 and 5 micrograms.kg-1, in a placebo-controlled double-blind trial in 75 patients undergoing laparoscopic cholecystectomy. The study drugs were administered intravenously 8 min before induction of anaesthesia with thiopentone 5 mg.kg-1 and vecuronium 0.1 mg/kg-1. Buprenorphine 2.5 micrograms.kg-1 caused 50% attenuation of the blood pressure response whereas 5 micrograms/kg-1 caused 70% attenuation compared to the saline placebo. The maximum increase in heart rate was 14% of the control value after 2.5 micrograms.kg-1 and 11% after 5 micrograms/kg-1 of buprenorphine. A significant difference in heart rate was also observed between the two buprenorphine groups at 5 and 10 min after intubation. Blood pressure and heart rate both showed a significant fall from baseline values 10 min after intubation in both buprenorphine groups, with the changes being greater in the 5 micrograms.kg-1 group. We recommend the use of 2.5 micrograms.kg-1 buprenorphine for attenuation of the hypertensive response to intubation in major abdominal surgery.     

Attenuation of the haemodynamic responses to noxious stimuli in patients undergoing cataract surgery. A comparison of magnesium sulphate, esmolol, lignocaine, nitroglycerine and placebo given i.v. with induction of anaesthesia

A study was conducted on 100 middle-aged to elderly patients (n = 52, healthy; n = 48, suffering from either diabetes, hypertension, ischaemic heart disease or a combination of these diseases) undergoing cataract extraction to assess the effects of laryngoscopy and tracheal intubation, anaesthesia and surgery, eye bandaging and tracheal extubation, saline (control), magnesium sulphate 40 mg kg-1, esmolol 4.0 mg kg-1, lignocaine 1.5 mg kg-1 and glyceryl trinitrate 7.5 micrograms kg-1 given i.v. at induction of anaesthesia on heart rate (HR), blood pressure (BP), rate-pressure product (RPP) and pressure-rate quotient (PRQ). Anaesthesia was standardized. Haemodynamic responses and requirements for atropine, ephedrine and labetalol to maintain HR and BP during surgery were similar in healthy and diseased patients, and in the test drug groups. Differences produced by the test drugs were evident until 5 min following intubation. Esmolol prevented rises in HR and RPP. Glyceryl trinitrate prevented a rise in BP, but was associated with tachycardia and a fall in PRQ to < 1.0. Magnesium sulphate and lignocaine did not prevent responses to laryngoscopy and tracheal intubation, and were associated with rises in RPP. Application of the eye dressing and tracheal extubation at the end of surgery each caused significant increases in HR, BP and RPP in all groups.     

Reduction in post-intubation respiratory resistance by isoflurane and albuterol

PURPOSE: This study examined the bronchodilating effects of 0.6 MAC and 1.1 MAC isoflurane (ISF) on respiratory system resistance (Rrs) following tracheal intubation and determined whether albuterol supplements that effect. METHODS: Sixty-seven adult patients were anaesthetized with 2 micrograms.kg-1 fentanyl and 5 mg.kg-1 thiopentone and their tracheas intubated following administration of 1 mg.kg-1 succinylcholine. Respiratory system resistance was measured following intubation and the patients then randomized to receive either 1.1 MAC ISF in oxygen or 0.6 MAC ISF in 50% nitrous oxide and oxygen. Ten minutes later, Rrs was again measured. Patients were then further randomized to receive albuterol or a placebo using incremental doses of 2, 5, and 10 puffs (albuterol puff = 90 micrograms) delivered via a metered dose inhaler at ten minute intervals. RESULTS: Isoflurane at 1.1 MAC decreased post-intubation Rrs by 23 +/- 5% (mean +/- sem) whereas the decrease was only 7 +/- 5% for 0.6 MAC ISF (P < 0.01). Two puffs of albuterol resulted in a further decrease of 12 +/- 3% (mean +/- sem) in Rrs compared with a 2 +/- 4% decrease in the placebo groups (P < 0.05). Additional puffs of albuterol resulted in no further changes in Rrs. CONCLUSION: We conclude that following tracheal intubation the reduction in Rrs produced by ISF is highly concentration dependent. Albuterol results in a small further reduction in Rrs.     

Usefulness of the intubating laryngeal mask airway for cases with predicted difficult intubation

We evaluated the usefulness of the intubating laryngeal mask airway (ILMA) in patients who were predicted to have possible difficult airway. Patients with possible difficult airway were defined as those with limited head extension, Mallampati's classification of grade IV, thyro-mental distance < 4 cm, or Cormack grade III-IV on the laryngoscopy. The control group was consisted of the patients without these conditions or impaired mouth opening. Insertion of the ILMA was successfully performed in all patients of both groups. In the group of possible difficult airway, 83% of patients were intubated through the ILMA successfully, and in the control group, 86%. We conclude that the ILMA may become an additional tool in patients with difficult intubation.     

Circulatory changes at the time of anesthetic induction and endotracheal intubation--comparison of thiamylal induction group and propofol induction group

We examined the circulatory changes after intravenous thiamylal with additional injection of thiamylal 1 minute before intubation and after propofol at the time of anesthetic induction and endotracheal intubation. Sixty ASA I or II patients were studied after the institutional and informed consents. We compared the following three groups. Group I (n = 20): Anesthesia was induced with thiamylal 5 mg.kg-1 and intubation with the aid of vecuronium 0.1 mg.kg-1. Group II (n = 20): Anesthesia was induced with thiamylal 3 mg.kg-1 and vecuronium 0.1 mg.kg-1. One minute before the intubation, the patients received additional thiamylal 4 mg.kg-1. Group III (n = 20): Anesthesia was induced with propofol 2.5 mg.kg-1 and intubation was performed with the aid of vecuronium 0.1 mg.kg-1. We examined the systolic, diastolic and mean blood pressures, heart rate, and rate pressure product (RPP) in the three groups. The examinations were performed before and after induction, soon after intubation, and every one minute after intubation for 5 minutes. After the endotracheal intubation, the systolic blood pressure and heart rate increased in Group I. But the systolic and diastolic pressures were significantly more stable in Group II and Group III. The change of the RPP was slight and most stable in Group II compared with the other two groups. We conclude that additional injection of thiamylal 4 mg.kg-1 following induction of anesthesia with thyamylal 3 mg.kg-1 1 minute before endotracheal intubation is an effective method for minimizing the increase in blood pressure and circulatory changes at the time of rapid induction of anesthesia and endotracheal intubation.     

The laryngeal mask--a valuable instrument for cases of difficult intubation in children. Anesthesiologic management in the presence of Pierre-Robin syndrome

In cases of craniofacial and mandibulofacial malformations, which are mostly treated during childhood, difficult intubation conditions must generally be expected. In such cases, the laryngeal mask airway (LMA) an alternative instrument for use in endotracheal intubation is a new aid for ventilation. In certain instances, it can be used alone to induce general anaesthesia. Reports of endotracheal intubation by means of the LMA in adults have also been published. CASE REPORT: In our case, a 6-year-old boy with Pierre-Robin syndrome (triad: micrognathia, broad palatoschisis, glossoptosis) needed dental resetting. After induction of anaesthesia in this very cooperative boy with thiopentone and fluothane and relaxation with succinylcholine, it was not possible to examine the hypopharynx by laryngoscopy preparatory to nasal intubation as usual. Repeated blind attempts at nasal intubation (again with spontaneous breathing) failed, as did the attempt at fibreoptic bronchoscopic intubation, because of the narrow anatomical conditions. Finally, a laryngeal mask airway (LMA; size 2) was introduced, and as a result of this ventilation was achieved. However, endotracheal intubation was required for performance of the surgical resetting. With the fibreoptic bronchoscope, we could verify the central position of the LMA over the glottis. A tracheal tube (size 4) was inserted across the laryngeal airway without optic control. The tube connector was disconnected and a normal guide inserted into the tube to remove the LMA. The dental resetting was also performed by oral intubation. CONCLUSION: Therefore, the LMA is not only a ventilation aid, but also a valuable tool in difficult intubation conditions. In our opinion, it is necessary to provide this tool in every anaesthetic unit.     

Comparison of remifentanil in combination with isoflurane or propofol for short-stay surgical procedures

There are few data in the literature that describe the use of remifentanil when administered as a component of an inhalation or total i.v. anaesthetic (TIVA) technique. We studied 251 male and female patients, aged 18-75 years, ASA I-II, undergoing inguinal hernia repair, arthroscopic knee surgery or varicose vein surgery of at least 30 min duration without premedication. Patients were randomized to receive a remifentanil loading dose of 1.0 microgram kg-1 followed by a continuous infusion of 0.5 microgram kg-1 min-1 in combination with isoflurane (end-tidal concentration 0.6%), (Group I, n = 115) or propofol (initial infusion rate 9 mg kg-1 h-1 reduced to 6 mg kg-1 h-1 after 10 min), (Group P, n = 118). The remifentanil infusion rate was reduced by 50%, 5 min after tracheal intubation. Intraoperative stresses were treated with a remifentanil bolus (1 microgram kg-1) followed by an increase in the remifentanil infusion rate. At the insertion of the last suture, the remifentanil infusion and concomitant anaesthetic were switched off simultaneously. Times to spontaneous respiration, adequate respiration and tracheal extubation were significantly shorter in group I compared with group P (6.4 min vs 7.6 min, P < 0.01; 7.6 min vs 9.3, P < 0.003; 7.8 min vs 9.5 min, P < 0.015). Overall mean systolic blood pressures during surgery were greater in group P compared with group I (P < 0.05) but the absolute differences were clinically insignificant (4-5 mm Hg).     

Intubation conditions: importance of the rate of repetition of the train-of-four

OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium.     

Use of total myorelaxation for placing a laryngeal mask and further artificial lung ventilation

The specific features of placing a laryngeal mask (LM) under total myoplegia were studied. The first attempt at placing LM was successful in 98.7% of cases. A pressor response to LM appeared as increases in heart rate by 5.6% with combined intravenous ketamine anesthesia used during laparoscopic cholecystectomies (Group 1), by 10.2% at saphenectomies (Group 2), and by 6.7% with barbiturates. When diprivan was used, changes were absent in Group 1, there were increases in mean blood pressure and heart rate by 10 and 6.6%, respectively, in Group 2. The response to tracheal intubation was significant under all types of anesthesia. Regurgitation and aspiration were absent in all groups. The use of total myoplegia to place LM allows different current anesthetics to be used in the optimal doses and the procedure for placing LM to be greatly simplified.     

Hemodynamic response to induction and intubation. Propofol/fentanyl interaction

BACKGROUND: When given as an intravenous bolus for induction of anesthesia, propofol can decrease postintubation hypertension but can also create moderate to severe postinduction, preintubation hypotension. The addition of fentanyl usually decreases the postintubation hypertension but can increase the propofol-induced preintubation hypotension. The goal of the study was to determine the relation between propofol and fentanyl doses and the hemodynamic changes post-induction, preintubation and postintubation. METHODS: Twelve groups of 10 patients, ASA physical status 1 or 2, first received fentanyl 0, 2, or 4 micrograms.kg-1 and then 5 min later received propofol 2.0, 2.5, 3.0, or 3.5 mg.kg-1 as an intravenous bolus for induction of anesthesia. Arterial blood pressure was continuously monitored. The trachea was intubated 4 min after propofol administration. RESULTS: The mean decrease in systolic blood pressure after propofol was 28 mmHg when no fentanyl was given, 53 mmHg after 2 microgram.kg-1 of fentanyl (P < 0.05 vs. no fentanyl), and 50 mmHg after 4 micrograms.kg-1 (P < 0.05 vs. no fentanyl; no statistically significant difference 4 vs. 2 micrograms.kg-1). There was no statistically significant difference in hemodynamic response to intubation relative to propofol dose. Hemodynamic response to intubation was decreased by the administration of fentanyl; the mean increase of systolic blood pressure after intubation was 65 mmHg from preintubation value without fentanyl, 50 mmHg after 2 micrograms.kg-1, and 37 mmHg after 4 micrograms.kg-1 (P < 0.05 for 2 and 4 micrograms.kg-1 vs. no fentanyl and for 4 vs. 2 micrograms.kg-1). Hemodynamic changes postintubation were not statistically different with increasing doses of propofol. CONCLUSIONS: Hemodynamic changes after induction with propofol or propofol/fentanyl, pre- or postintubation, are not modified when the propofol dose is increased from 2 to 3.5 mg.kg-1. Maximal hypotension preintubation occurs with a fentanyl dose of 2 micrograms.kg-1, whereas the magnitude of postintubation hypertension is significantly decreased with an increase in the fentanyl dose to 4 micrograms.kg-1.     

Familial occurrence of temporal arteritis

The incidence of difficulty in tracheal intubation in the presence of goiter was investigated. Data were collected in a series of 4742 consecutive adult patients undergoing general anesthesia. The prevalence of goiter was 6.8%. Fifteen anesthesiologists performed the preoperative airway assessment using standardized guidelines. Seven individual risk factors were correlated with the potential for difficult tracheal intubation. Whenever evidence of goiter or airway pathology was observed, the evaluation was completed by indirect laryngoscopy and radiologic examination to establish the presence of any anatomical deviation. Difficult intubation was defined as inadequate exposure of the glottis by direct laryngoscopy. There was no difference in probability of difficulty in tracheal intubation between patients who presented for thyroidectomy and patients with goiter estimated as a random finding. Statistical analysis revealed an increased risk of difficult intubation amongst goiter patients compared with patients with no evidence of any risk factor (6.8% vs 0.9%, P < 10(-8), relative risk = 7.4). We conclude that goiter, when accompanied by airway deformity, constitutes an aggravating factor for difficult intubation.     

Light-guided intubation using Trachlight

BACKGROUND: A new intubating transilluminated device (Trachlight) has been recently proposed as an alternative to tracheal intubation with direct laryngoscopy. OBJECTIVE: 1) To evaluate Trachlight device in orotracheal intubation and to assess its operation and complications. 2) To compare the time consumption of transillumination intubation in respect to direct laryngoscopy on the same patients. METHODS: The first study was performed on 50 patients undergoing elective surgery and submitted to Trachlight intubation alone; speed of intubation, number of attempts and all complications were recorded and related to Mallampati classes. In the second study 16 patients undergoing to elective surgery were enrolled. Each patient was classified according to both the Mallampati classes and the Cormack classes. Each patient was submitted to two tracheal intubations: the first with the Trachlight and the second with conventional direct laryngoscopy performed by the same anesthesiologist. The time to intubation and the number of attempts were recorded and related to the Mallampati and Cormack classes. RESULTS: In the first study time of intubation with Trachlight was 20.93 +/- 13.02s (mean +/- SD) without statistical differences in respect to the Mallampati classes. In the second study the times to intubation were without any statistical difference independently of the technique of intubation and of the Mallampati or Cormack classes. CONCLUSIONS: Orotracheal intubation using Trachlight appears to be an effective and easy to learn technique, being also easy, safe and fast to carry out. The comparison with direct laryngoscopy showed the same speed and effectiveness even on patients with difficult intubation.     

Induction of anesthesia and tracheal intubation with sevoflurane in adults

BACKGROUND: The speed, quality, and cost of mask induction of anesthesia and laryngeal mask airway insertion or tracheal intubation were studied in young non-premedicated volunteers given high inspired concentrations of sevoflurane (6 to 7%). METHODS: Twenty healthy persons who were 19 to 32 years old participated three times, received 6 l/min fresh gas flow, and were randomized to receive 6 to 7% sevoflurane in 66% nitrous oxide/28% oxygen by face mask until tracheal intubation (treatment 1) or until laryngeal mask airway insertion (treatment 3), or 6 to 7% sevoflurane without nitrous oxide to tracheal intubation (treatment 2). Participants exhaled to residual volume and took three vital capacity breaths of the gas mixture; thereafter ventilation was manually assisted. The time of exposure to the inhaled gas was varied for consecutive participants. It was either increased or decreased by 30-sec increments based on the failure or success of the preceding volunteer's response to laryngoscopy and intubation after a preselected exposure time. Failure was defined as poor jaw relaxation, coughing or bucking, or inadequate vocal cord relaxation. RESULTS: Loss of the lid-lash reflex in unpremedicated young volunteers was achieved in 1 min and did not differ among groups. Average time (and 95% confidence interval) for acceptable conditions for LMA insertion was achieved in 1.7 (0.7 to 2.7) min, and all participants had an immediate return of spontaneous ventilation. The time for acceptable tracheal intubating conditions after manual hyperventilation by mask was 4.7 (3.7 to 5.7) min and 6.4 (5.1 to 7.7) min in treatments 1 and 2, respectively. There were no cases of increased secretions or laryngospasm. The incidence of breath holding and expiratory stridor ("crowing") was 7.5% and 25%, respectively, during treatment 1 and 15% and 40%, respectively, during treatment 2. CONCLUSIONS: The induction of anesthesia to loss of lid reflex in young non-premedicated adults approaches the speed of intravenous induction techniques. No untoward airway responses were noted during mask induction of anesthesia with a three-breath technique. In response to intubation, no adverse airway responses, including jaw tightness, laryngospasm, and excessive coughing or bucking, occurred in participants whose duration of mask administration of sevoflurane met the appropriate times (as determined in this study).     

Thiopental or etomidate for rapid sequence induction with rocuronium

We have assessed the effect of the choice of i.v. induction agent on intubation conditions, 60 s after administration of rocuronium 0.6 mg kg-1. We studied 60 adult patients, allocated randomly to one of two groups. Anaesthesia was induced with alfentanil 10 micrograms kg-1 followed by thiopental 5 mg kg-1 (AT-R group; n = 30) or etomidate 0.3 mg kg-1 (AE-R group; n = 30). Both groups received rocuronium 0.6 mg kg-1. Laryngoscopy was started 60 s later and intubation conditions were evaluated according to a standard score, which considered ease of laryngoscopy, condition of the vocal cords and reaction to intubation. In the AT-R group, overall intubation conditions were scored as excellent in 20 patients, good in nine and fair in the remaining patient. In the AE-R group, overall intubating conditions were excellent in 24 and good in six patients. The difference between the two groups was not significant. Of the three components of the intubation score assessed, response to intubation stimulus was significantly less pronounced in group AE-R compared with group AT-R (P < 0.05): group AE-R, no reaction in 24 patients, slight diaphragmatic movement in five and mild coughing in one patient; group AT-R, no reaction in 13, slight diaphragmatic movement in 14, mild coughing in two and severe coughing in one patient. We conclude that etomidate as part of an induction regimen containing alfentanil and rocuronium attenuated the reaction to intubation to a greater extent than thiopental.