Airway management in neuroanaesthesia

The Use of the Shikani Video-Assisted Intubating Stylet Technique in Patients with Restricted Neck Mobility

Among all the proposed predictors of difficult intubation defined by the intubation difficulty scale, head and neck movement (motility) stands out and plays as a crucial factor in determining the success rate and the degree of ease on endotracheal intubation. Aside from other airway tools (e.g., supraglottic airway devices), optical devices have been developed and applied for more than two decades and have shown their superiority to conventional direct laryngoscopes in many clinical scenarios and settings. Although awake/asleep flexible fiberoptic bronchoscopy is still the gold standard in patients with unstable cervical spines immobilized with a rigid cervical collar or a halo neck brace, videolaryngoscopy has been repeatedly demonstrated to be advantageous. In this brief report, for the first time, we present our clinical experience on the routine use of the Shikani video-assisted intubating stylet technique in patients with traumatic cervical spine injuries immobilized with a cervical stabilizer and in a patient with a stereotactic headframe for neurosurgery. Some trouble-shooting strategies for this technique are discussed. This paper demonstrates that the video-assisted intubating stylet technique is an acceptable alternative airway management method in patients with restricted or confined neck motility.

Intubation without premedication may worsen outcome for unconsciousness patients with intracranial hemorrhage

To clarify the influence of an intubation maneuver with or without premedication for an intracranial hemorrhage in an unconsciousness patient, we retrospectively analyzed 70 patients who had received intubation for unconsciousness and in whom a nontraumatic intracranial hemorrhage was found by CT over a 6-year period. They were divided into 2 groups, consisting of a drug group (n=15), wherein drugs were used before intubation, and control group (n=55), wherein no drugs were used before were intubation. The physical findings on admission, CT findings, Glasgow Outcome Score (GOS) at 3 months from admission were analyzed between the groups. There were no significant differences in the backgrounds of the subjects between the groups. The GOS in the control group was significantly higher than in the drug group (P<.001). In cases of intubation for unconscious patients who may have intracranial hemorrhaging, premedication is considered associated with a more favorable outcome.

[Anesthetic particularities of stereotaxic neurosurgery]

Functional neurosurgery procedures are long and specific. Cooperation of the patient may be necessary during surgery. The interference of anaesthetic agents with electrophysiological monitoring should be as little as possible. Local anaesthesia combined with intravenous sedation is often used, but general anaesthesia is more comfortable and secure. Since awakening during the procedure is generally planed, it has to be quick, reliable and of excellent quality. These requirements are fulfilled by the association of propofol by target-controlled infusion (TCI) and a continuous infusion of remifentanil.

Voluntary hyperventilation before a rapid-sequence induction of anesthesia does not decrease postintubation PaCO2

To prevent hypercapnia, voluntary hyperventilation is recommended for patients with increased intracranial pressure before the induction of general anesthesia. We sought to determine whether this maneuver results in a lower PaCO2 than breathing 3 min of oxygen 100% by face mask (preoxygenation) after intubation. Thirty patients requiring general anesthesia were randomly assigned to breathe either 3 min of oxygen 100% by face mask (Group P) or 1 min of oxygen 100% followed by 2 min of voluntary hyperventilation with oxygen 100% (Group H). All patients received a standard rapid-sequence induction of anesthesia followed by a 90-s period of apnea. Patients were then tracheally intubated and mechanically ventilated. Five arterial blood gas samples were taken: with room air, after preoxygenation or hyperventilation, after 60 and 90 s of apnea, and after tracheal intubation. Voluntary hyperventilation decreased PaCO2 before rapid-sequence induction (hyperventilation, 30.0 +/- 3.5 mm Hg versus preoxygenation, 37.9 +/- 5.2 mm Hg; P < 0.0001), but after 60 s of apnea, both groups had similar PaCO2 (hyperventilation, 36.1 +/- 3.3 mm Hg versus preoxygenation, 35.6 +/- 3.4 mm Hg; P = 0.673), and no benefit was found after intubation (hyperventilation, 40.5 +/- 3.9 mm Hg versus preoxygenation, 41.4 +/- 2.7 mm Hg; P = 0.603). We conclude that voluntary hyperventilation before rapid-sequence induction does not provide protection against potential hypercapnia during intubation.

IMPLICATIONS

Voluntary hyperventilation before anesthesia induction is recommended for patients with increased intracranial pressure to prevent hypercapnia. This randomized, prospective study demonstrated that this maneuver does not result in a lower postintubation PaCO2 than standard preoxygenation.

Emergent airway management. Indications and methods in the face of confounding conditions

Optimal airway management requires an experienced caregiver, attention to detail, and knowledge of the patient's physiology. A variety of pharmacologic agents have proved useful in obtaining a secure airway and minimizing risk to the patient. Depending on the skills of the caregiver, oral intubation has become the preferred means of airway control in most patients. Advances in technique, equipment, and pharmacology have greatly improved the art of airway management; however, there is no substitute for an experienced clinician.

Cardiovascular stability during carotid endarterectomy: endotracheal intubation versus laryngeal mask airway

STUDY OBJECTIVE

To compare cardiovascular stability during carotid endarterectomy in groups managed either with laryngeal mask airway (LMA) or endotracheal intubation.

DESIGN

Randomized, retrospective, blinded study.

SETTING

Teaching hospital.

PATIENTS

61 ASA physical status II, III, and IV unpremedicated adult males scheduled for carotid endarterectomy.

INTERVENTIONS

Following standardized anesthetic technique, including intravenous (i.v.) induction with thiopental sodium 3 to 4 mg/kg, fentanyl 2 to 3 microg/kg), and isoflurane, standard intraoperative cardiovascular monitoring plus direct arterial blood pressure measurements were instituted. Patients were randomly assigned to an endotracheal intubation or LMA group.

MEASUREMENTS AND MAIN RESULTS

Distinct intraoperative episodes of +/- 25% increase or decrease of mean arterial blood pressure (MABP) and heart rate (HR) when compared with preinduction baseline values, and the number of such episodes requiring interventional therapy were recorded from a blinded anesthesia record retrospectively. Mean end-tidal isoflurane determination and total case duration enabled calculation of minimum alveolar concentration (MAC) hours of isoflurane administered. The LMA group had a significantly (p < 0.05) lower incidence of increased MABP and HR episodes and such episodes requiring drug therapy than did the endotracheal intubation group. No difference was found in the length of surgery, mean end-tidal isoflurane concentration, or the total number of MAC hours of isoflurane administered.

CONCLUSIONS

During carotid endarterectomy, a reduced incidence of hypertensive and tachycardic episodes, as well as such episodes requiring interventional drug therapy, was found in the group whose airway is managed by LMA when compared with endotracheal intubation.

Anaesthetic considerations for children undergoing stereotactic radiosurgery

An anaesthetic case report of children undergoing stereotactic radiosurgery is presented, with a review of the inherent unique anaesthetic challenges. Twelve stereotactic radiosurgery procedures performed at The Prince of Wales Hospital, Sydney, were retrospectively reviewed. Despite differences in approach by individual anaesthetists to managing these children, an overall safe sequence may be evolved. The use of stereotactic radiosurgery for paediatric neuropathology is reviewed. The potential anaesthetic problems related to the paediatric patient and the peculiarities of the procedure are discussed and related to our series.