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We read with great interest the anesthetic technique of using a gum elastic bougie (GEB) for nasal intubation in a recent issue of Anesthesia Progress. The authors recommend the use of GEB for the first attempt of nasotracheal intubation in patients with a difficult airway. We agree that this is an excellent alternative. We also have found an excellent variation of this method that utilizes a double bougie technique for insertion of a nasotracheal tube if the difficult airway can be secured initially with an orotracheal tube.

Purpose: To report a case of unusual difficult intubation secondary to oral submucosal fibrosis (SMF) associated with malignancy of the hypopharynx., Clinical Features: A 57-yr-old male, ASA-I physical status presented for percutaneous nephrolithotripsy. The patient was a known alcoholic and smoker with a habit of chewing quids for the past 36 years. Airway assessment revealed oral SMF and slight difficulty in opening the mouth fully. Mentohyoid and mentothyroid distances were normal. However, during intubation, unanticipated difficulty was encountered. On direct laryngoscopy, the tip of the epiglottis could barely be visualized. Intubation was possible after passing a gum elastic bougie blindly under the epiglottis and negotiating a 7.0 internal diameter tracheal tube over it. Postoperatively, indirect laryngoscopy (IDL) showed severe SMF involving the oral cavity, epiglottis and pyriform fossae and an ulcerative malignancy of the hypopharynx with fixation of the left hemilarynx., Conclusion: SMF is a premalignant condition of the oral cavity associated with fibrosis of involved structures that can be associated with malignancy of the aerodigestive tract. Distortion of the airway anatomy may render intubation difficult. IDL maybe useful in the preoperative evaluation of these patients.

Unlabelled: Neuromuscular block (NMB) at the larynx has been assessed by measuring the cuff pressure (CP) in an endotracheal tube (ETT) placed between the vocal cords. In this study, we evaluated the decrease in resting cuff pressure (RCP) after the administration of rocuronium and the effect of this decrease on the assessment of NMB, and we compared CP measurement with an alternative technique, video imaging (VI). In 20 patients, NMB was determined at the hand by mechanomyography and at the larynx initially by CP and subsequently by VI, recording images using a fiberoptic bronchoscope via a laryngeal mask. Train-of-four stimuli were applied at both sites. After baseline measurements, the ETT was replaced, and rocuronium was infused to achieve a steady-state 50% (n = 10) or 75% (n = 10) block at the hand. CP measurements were recorded before and after restoration of RCP to prerocuronium pressure, followed by further VI measurements. The mean RCP decreased from 21 +/- 4 to 12 +/- 5 mm Hg after rocuronium. At 50% block at the hand, the CP estimate of block at the larynx with reduced RCP was 62% +/- 18%, and that after restoring RCP was 29% +/- 13%; VI estimated 27% +/- 14% block. At 75% block at the hand, CP and VI estimated 52% +/- 11% and 46% +/- 9% block, respectively (RCP maintained). We conclude that RCP decreases after the administration of rocuronium, that restoring RCP significantly alters CP estimates of NMB, and that VI is in agreement with CP measurement if RCP is maintained at prerelaxant values., Implications: In this study, we show that a muscle relaxant-induced decrease in resting tension at the larynx may confound the assessment of neuromuscular block by cuff pressure measurement. The preliminary data suggest that video imaging may provide a suitable alternative to cuff pressure measurement to assess neuromuscular block at the larynx.

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.

Thirty adult patients who underwent coronary artery bypass graft surgery were allocated randomly to one of two equal groups to receive either 2% nitroglycerin, or a placebo ointment, applied topically over an area of 5 cm by 10 cm, in a double-blind manner, 1 h before induction of anaesthesia. Premedication consisted of oral diazepam 5-10 mg, intramuscular morphine 0.2 mg.kg-1 and promethazine 0.4 mg.kg-1. Anaesthesia was induced with morphine 0.15-0.2 mg.kg-1 and thiopentone 3-5 mg.kg-1. Laryngoscopy and tracheal intubation were facilitated by suxamethonium 1.5 mg.kg-1, and pancuronium 0.1 mg.kg-1 was used for subsequent muscle relaxation. Anaesthesia was maintained with 0.5% halothane and 40% oxygen in nitrous oxide. A significant increase in blood pressure occurred during and after laryngoscopy and tracheal intubation, and following midline sternotomy in the control group. These changes were absent in patients pretreated with topical nitroglycerin. The nitroglycerin group also maintained a lower rate-pressure product than the control group. We conclude that topical nitroglycerin is a simple and useful pretreatment to prevent the pressor response to tracheal intubation and midline sternotomy in patients undergoing coronary artery bypass graft surgery.

Estimation of the correct length of a tracheal tube is extremely important and should be tailored to the needs of the individual patient. One hundred and eight patients who required tracheal intubation during anaesthesia were studied. The predicted length was estimated in each patient before induction of anaesthesia. The upper end of the cuff was aligned externally with the cricoid cartilage, while the more proximal part of the tube lay alongside the neck to the angle of the mandible. The tube was then curved forwards towards the upper incisor teeth, and the length at the teeth or gums was noted. The anaesthetist, who was unaware of the predicted length, intubated the trachea after induction of anaesthesia. The length of tube inserted was standardised in relation to the vocal cords, and the actual length of tube inserted was recorded. The estimated length was within 1.0 cm and 1.5 cm of the actual length in 91% and 97% of patients respectively.

The efficacy of sublingual nifedipine, administered one minute before anaesthetic induction, in order to minimise the pressor response to laryngoscopy and tracheal intubation was studied in a group of 15 patients who underwent coronary artery bypass surgery. Another group of 15 similar patients served as control. Premedication consisted of oral diazepam 5-10 mg, intramuscular morphine 0.2 mg/kg and promethazine 0.4 mg/kg. Anaesthesia was induced with morphine 0.1-0.15 mg/kg and thiopentone 3-5 mg/kg. Laryngoscopy and tracheal intubation were facilitated with suxamethonium 1.5 mg/kg. A significant increase in blood pressure occurred during and after laryngoscopy and tracheal intubation in the control group. This increase was absent in the patients pretreated with nifedipine. The nifedipine group also maintained a lower rate-pressure-product than the control group during the period of study. It is concluded that nifedipine 10 mg is a useful pretreatment to prevent the pressor response to laryngoscopy and tracheal intubation in patients with coronary artery disease.

Two separate studies of the effects of nitroglycerin (NTG) on intraocular pressure (IOP) were conducted. In study I, 12 healthy adults received 3 ml NTG solution (2 mg/3 ml) intranasally during steady-state anesthesia. This resulted in a significant decrease in IOP along with decreases in arterial blood pressure and central venous pressure. In study II, 30 patients, classified randomly into two equal groups, received either normal saline (3 ml) or NTG solution (2 mg/3 ml) intranasally, in a double-blind manner, 2 minutes before anesthetic induction with thiopental followed by succinylcholine (1.5 mg/kg). In patients given saline, IOP increased significantly above the preinduction levels after succinylcholine. Tracheal intubation increased it further. In the NTG group, increases in IOP after succinylcholine and after tracheal intubation were significantly less than in the control (saline) group. It is concluded that intranasal administration of NTG decreases IOP in anesthetized patients and, when employed as pretreatment, allows the use of succinylcholine to facilitate tracheal intubation without an increase in IOP above preinduction levels.

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.