Awake Tracheal Intubation Research Articles

Management of the Difficult Adult Airway With Special Emphasis on Awake Tracheal Intubation

Difficulty in managing the airway is the single most important cause of major anesthesia-related morbidity and mortality. Successful management of a difficult airway begins with recognizing the potential problem. All patients should be examined for their ability to open their mouth widely and for the structures visible upon mouth opening, the size of the mandibular space, and ability to assume the sniff position. If there is a good possibility that intubation and/or ventilation by mask will be difficult, then the airway should be secured while the patient is still awake. In order for an awake intubation to be successful, it is absolutely essential that the patient be properly prepared; otherwise, the anesthesiologist will simply fulfill a self-defeating prophecy. Once the patient is properly prepared, it is likely that any one of a number of intubation techniques will be successful. If the patient is already anesthetized and/or paralyzed and intubation is found to be difficult, many repeated attempts at intubation should be avoided because progressive development of laryngeal edema and hemorrhage will develop and the ability to ventilate the lungs via mask consequently may be lost. After several attempts at intubation, it may be best to awaken the patient, do a semielective tracheostomy, or proceed with the case using mask ventilation. In the event that the ability to ventilate via mask is lost and the patient's lungs still cannot be ventilated, TTJV should be instituted immediately. Tracheal extubation of a patient with a difficult airway over a jet stylet permits a controlled, gradual, and reversible (in that ventilation and reintubation is possible at any time) withdrawal from the airway. Significant advances in the management of the difficult airway have occurred in recent years. Eighty percent of the 127 references in this article were published after 1985. However, there is much more to learn with regard to recognition of the difficult airway, preparation of the patient for an awake intubation, new techniques of endotracheal intubation, and establishment of gas exchange in patients who cannot be intubated or ventilated by mask. As the anesthesiologist's ability to manage the difficult airway significantly improves, respiratory-related morbidity and mortality will decrease.

Minimum Alveolar Concentration of Desflurane and Hemodynamic Responses in Neonates, Infants, and Children

We sought to determine the minimum alveolar concentration (MAC) and hemodynamic responses to desflurane in 72 fasting and unpremedicated full-term neonates, infants, and children up to 12 yr of age. The patients were divided into six groups (n = 12) according to age. After awake tracheal intubation, neonates were anesthetized with desflurane in oxygen and air. Infants greater than 1 month of age and all older children were anesthetized with desflurane in 100% oxygen, and their tracheas were intubated without muscle relaxation. MAC was determined using the "up-and-down technique" and logistic regression. Heart rate and systolic arterial pressure were recorded awake, at approximately 1 MAC desflurane before skin incision and at approximately 1 MAC during the peak hemodynamic responses to skin incision. We found that the relationship between MAC (mean +/- standard deviation) as determined by the up-and-down technique and age was quadratic, reaching a maximum value in infants 6-12 months of age: in neonates 0-1 month MAC was 9.16 +/- 0.02%, in infants 1-6 months 9.42 +/- 0.06%, in infants 6-12 months 9.92 +/- 0.44%, in children 1-3 yr 8.72 +/- 0.59%, in children 3-5 yr 8.62 +/- 0.45%, and in children 5-12 yr 7.98 +/- 0.43%. MAC values obtained using logistic regression were similar. Heart rate decreased an average of 16% before skin incision in infants 6-12 months of age and children 1-3 and 3-5 yr of age when compared to awake values (P less than 0.025) but did not change significantly in the remaining three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in Anterior Fontanel Pressure in Preterm Neonates during Tracheal Intubation

Anterior fontanel pressure (AFP), a noninvasive indicator of intracranial pressure (ICP), was monitored during tracheal intubation in two groups of preterm neonates without neurologic disease. Anterior fontanel pressure was monitored and recorded continuously with a Ladd AFP monitor. Systolic and mean blood pressures were recorded at 1-min intervals. In group 1 (n = 6) patients, 0.02 mg/kg intravenous atropine was administered and awake intubation was performed. Group 2 (n = 6) patients received 0.02 mg/kg intravenous atropine and 0.1 mg/kg pancuronium and one of four anesthetics--0.75% isoflurane, 0.5% halothane, 20 micrograms/kg fentanyl, or 2 mg/kg ketamine--with intubation after 10 min of mask ventilation. In group 1, AFP increased from 7.7 cm H2O to 23.8 cm H2O (P less than 0.05); the mean increase in AFP was 197%. Anterior fontanel pressure did not change significantly in group 2. Significant increases in AFP may increase the risk of intraventricular hemorrhage in preterm neonates. The present data indicate that indirectly measured ICP increases significantly during awake tracheal intubation in preterm neonates and that this increase can be prevented by prior administration of pancuronium and a general anesthetic.

Cardiovascular Responses and Lidocaine Absorption in Fiberoptic-Assisted Awake Intubation

Local anesthetic toxicity and cardiovascular stress during fiberoptic-assisted awake tracheal intubation were assessed prospectively in 20 patients with airway management problems. Cardiovascular responses, dose of lidocaine, its systemic absorption, and patient comfort were measured. A standardized topical anesthesia protocol of 4% lidocaine aerosol, topical 2% lidocaine viscous gel, and direct perbronchoscopic laryngeal application was used. Awake intubation produced no significant elevation of blood pressure or pulse rate either during the topical application or after the intubation. Despite a large total dose of topical lidocaine (5.3 +/- 2.1 mg/kg), the mean peak arterial plasma lidocaine concentration was low (0.6 +/- 2.1 micrograms/ml). Patient comfort assessment showed that nine patients had no discomfort, whereas 11 had minimal discomfort. Supplementary sedation used was minimal (fentanyl, 1.4 +/- 0.6 micrograms/kg, and diazepam, 1.9 +/- 1.8 mg). This method of producing topical anesthesia for awake tracheal intubation is recommended as a safe, easy, and comfortable method of managing patients with airway difficulties.

Tracheobronchomalacia in an adult with metaphyseal chondrodysplasia

Anaesthetic complications such as obstruction of airways by submucosal cartilage-bone protuberances, immobility of the neck or instability of the atlanto-axial joint have been described earlier in paediatric patients with congenital osteochondric disorders. This report concerns a case in which tracheal collapse due to tracheobronchial malacia in an adult patient with metaphyseal chondrodysplasia evidently caused severe ventilatory difficulties in the induction of anaesthesia. The management of the patient on three subsequent occasions is described. During the first operation, support of the upper respiratory tract was performed. For this procedure, awake tracheal intubation with local anaesthesia applied to the larynx, vocal cords and trachea was used. After surgical correction of the bronchus of the right upper lobe and the stem bronchus, subsequent anaesthesias for surgical treatment of scoliosis could be conducted safely. The possibility of co-existing tracheobronchial malacia in patients with osteochondrodysplasias should be considered and tracheal intubation under local anaesthesia is recommended.

Local Nerve Block Anesthesia for Peroral Endoscopy

Local glossopharyngeal and superior laryngeal nerve block anesthesia for peroral endoscopy was performed on 500 patients (313 bronchoscopies, 162 esophagoscopies, 25 combined bronchoesophagoscopies). The technique allows easy insertion of rigid and flexible scopes or awake tracheal intubation of conscious patients. Glossopharyngeal nerve block causes temporary abolition of the gag reflex and loss of tactile sensation over the posterior third of the tongue and the lateral and posterior wall of the oropharynx and hypopharynx. Superior laryngeal nerve block results in loss of tactile sensation over the posterior surface of the epiglottis and the mucosa of the larynx and upper trachea. Ten of the 500 patients (2%) had an inadequate glossopharyngeal block, and 4 of the 313 patients who had a bronchoscopic examination had an inadequate superior laryngeal block. In the remaining patients, excellent anesthesia was obtained with good patient acceptance and minimal morbidity.

Awake tracheal intubation in anaesthesia.

Endotracheal intubation in the awake patient was used on 500 occasions. Indications and results are discussed and analysed.