Sudden airway obstruction following inhalation drug abuse

Topicalisation of airway for awake fibre-optic intubation: Walking on thin ice

Topicalisation of the airway by various techniques has routinely been recommended for awake fibre-optic bronchoscopy in cases of difficult airway. However, topicalisation by itself can cause airway obstruction by decreasing the tone of the laryngeal muscles and causing a dynamic air inflow obstruction. Two cases of difficult airway are illustrated where anaesthetising upper airway with nebulisation with 4% lignocaine (Xylocaine™) or 2% lignocaine (Xylocaine™) jelly resulted in stridor and upper airway obstruction. This is the first reported case of airway obstruction after lignocaine (Xylocaine™) jelly. We would like to highlight that topicalisation of airway, once thought as a relatively safe technique, can cause airway collapse if not detected and anticipated at the earliest. Pre-operative spirometry and airway ultrasonography can be useful in detecting the patients at risk of developing airway obstruction. Using a nasopharyngeal airway during topicalisation can serve as a valuable device in preventing total airway obstruction in susceptible patients.

Stimulants and the lung : review of literature

Illicit stimulants, such as cocaine, amphetamine, and their derivatives (e.g., "ecstasy"), continue to exact heavy toll on health care in both developed and developing countries. The US Department of Health and Human Service reported over one million illicit drug-related emergency department visits in 2010, which was higher than any of the six previous years. Both inhaled and intravenous forms of these substances of abuse can result in a variety of acute and chronic injuries to practically every part of the respiratory tract, leading potentially to permanent morbidities as well as fatal consequences--including but not limited to nasal septum perforation, pulmonary hypertension, pneumothorax, pneumomediastinum, interstitial lung disease, alveolar hemorrhage, reactive airway disease, pulmonary edema, pulmonary granulomatosis, infections, foreign body aspiration, infections, bronchoconstriction, and thermal injuries. Stimulants are all rapidly absorbed substances that can also significantly alter the patient's systemic acid-base balance and central nervous system, thereby leading to further respiratory compromise. Mounting evidence in the past decade has demonstrated that adulterants coinhaled with these substances (e.g., levamisole) and the metabolites of these substances (e.g., cocaethylene) are associated with specific forms of systemic and respiratory complications as well. Recent studies have also demonstrated the effects of stimulants on autoimmune-mediated injuries of the respiratory tract, such as cocaine-induced midline destructive lesions. A persistent challenge to studies involving stimulant-associated respiratory toxidromes is the high prevalence of concomitant usage of various substances by drug abusers, including tobacco smoking. Now more than ever, health care providers must be familiar with the multitude of respiratory toxidromes as well as the diverse pathophysiology related to commonly abused stimulants to provide timely diagnosis and effective treatment.

Dynamic Airflow Limitation after Topical Anaesthesia of the Upper Airway

This prospective before-and-after observational study investigated the effect of upper airway anaesthesia on dynamic airflow. Six consenting ASA 1 adults, all authors of this study, underwent a series of Spirometric measurements before and after topical anaesthesia of the upper airway using lignocaine. Peak inspiratory flow rate, forced inspiratory flow between 25% and 75% of the maximum inhaled volume, forced expiratory volume at 1 second, and forced vital capacity in the supine and sitting positions were measured. The measured inspiratory parameters were significantly reduced after lignocaine topical anaesthesia of the upper airway. Expiratory flow parameters were not affected. We conclude that topical anaesthesia of the upper airway leads to dynamic inspiratory airflow limitation.

Total airway obstruction during local anesthesia in a non-sedated patient with a compromised airway

PURPOSE

To report a case of complete upper airway obstruction after topicalization with lidocaine in a completely conscious patient with partial upper airway obstruction.

CLINICAL FEATURES

A 69-yr-old man with a history of neck cancer and radiation presented for resection of recurrent neck tumour. No preoperative sedation was given. He had inspiratory and expiratory stridor but had no history of aspiration or swallowing problem. Phonation was distorted but effective. The surgeon was reluctant to perform an awake tracheostomy under local anesthesia. In preparation for a fibrescope-assisted orotracheal intubation, the non-sedated patient was given topical upper airway lidocaine during which he developed total airway obstruction and hypoxemia. He was immediately intubated with a fibrescope. His vocal cords were not edematous although the supraglottic structures appeared to be. The vocal cords were abducted and their movement was limited and not paradoxical. Tumour resection was uneventful upon successful tracheal intubation and general anesthesia. Tracheostomy at the end of the case was difficult, as expected. The patient tolerated the procedures and regained consciousness with no neurologic sequelae.

CONCLUSION

Dynamic airflow limitation associated with local anesthesia of the upper airway may lead to complete upper airway obstruction in a compromised airway. The main cause may be the loss of upper airway muscle tone, exacerbated by deep inspiration during panic.