Literature Updates from March 2012

Laryngoscopy in Conscious Patients with Remifentanil: How Useful is an “Awake Look”?

Using remifentanil as the sole analgesic allows evaluation of the larynx with direct laryngoscopy in a conscious patient. A poor Cormack-Lehane grade in a conscious patient may or may not improve with general anesthesia.

Difficult Airway Society Guidelines for the Management of Tracheal Extubation

Tracheal extubation is a high-risk phase of anaesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death. The need for a strategy incorporating extubation is mentioned in several international airway management guidelines, but the subject is not discussed in detail, and the emphasis has been on extubation of the patient with a difficult airway. The Difficult Airway Society has developed guidelines for the safe management of tracheal extubation in adult peri-operative practice. The guidelines discuss the problems arising during extubation and recovery and promote a strategic, stepwise approach to extubation. They emphasise the importance of planning and preparation, and include practical techniques for use in clinical practice and recommendations for post-extubation care.

Awake Videolaryngoscopy-Assisted Tracheal Intubation of the Morbidly Obese

Awake videolaryngoscopy may be useful for the tracheal intubation of the morbidly obese. This prospective, observational study enrolled 50 patients undergoing bariatric surgery. After sedation and topical anaesthesia of the airway, awake tracheal intubation was attempted, assisted by videolaryngoscopy, and terminated if there was severe gagging, coughing, or inadequate laryngeal view. When managing the morbidly obese airway, awake tracheal intubation using videolaryngoscopy may be considered.

The Treatment of Central Sleep Apnea Syndromes in Adults: Practice Parameters with an Evidence-Based Literature Review and Meta-Analyses

This is a well-conducted systematic review and meta-analysis addressing the treatment of central sleep apnea syndromes in adults.

Acute Upper Airway Responses to Hypoglossal Nerve Stimulation During Sleep in Obstructive Sleep Apnea

In this study, the authors studied response of pharyngeal airway to graded increase in hypoglossal nerve stimulation in 30 patients with OSA. It produced marked dose-related increases in the maximal inspiratory airflow.

Interrelationships Between Body Mass, Oxygen Desaturation, and Apnea-Hypopnea Indices in a Sleep Clinic Population

In this retrospective observational study conducted in the sleep clinic population, the authors evaluated the diagnostic utility of overnight desaturation index (ODI). Of the three ODI thresholds (ODI at 2%, 3%, and 4%) considered, the ODI 3% performed the best for the detection of moderate-to-severe OSA. The episodes of oxygen desaturation were more frequent in obese patients and therefore the sensitivity of ODI in subjects with BMI of less than 25 kg/m2 was found to be suboptimal.

Obstructive Sleep Apnea and Systemic Hypertension: Longitudinal Study in the General Population: The Vitoria Sleep Cohort

In this prospective cohort study, 2,148 subjects between the ages of 30 to 70 years were included from the general population in Spain. Out of 1,557 subjects who completed 7.5 years follow-up, 377 were excluded due to the presence of systemic hypertension (SH) at baseline. The crude odds ratio for incident hypertension was increased with higher respiratory disturbance index (RDI) category in a dose dependent manner. However, there was no statistically significant association between RDI and SH after adjusting for age, sex, body mass index, neck circumference, and fitness level and alcohol, tobacco, and coffee consumption.

Atelectasis and Perioperative Pulmonary Complications in High-Risk Patients

This review evaluates the link between perioperative lung atelectasis and postoperative pulmonary complications and how appropriate ventilatory strategies could mitigate this problem. A goal-directed ventilatory approach keeping an ‘open lung’ condition during the perioperative period may reduce the incidence of PPCs.

Postoperative Complications in Patients with Obstructive Sleep Apnea

In this historical cohort study, 471 patients who had undergone noncardiac surgery within 3 years of polysomnography were included in the study. The presence of OSA (defined as AHI ≥5/h) was associated with higher incidence of postoperative hypoxemia, overall complications, transfer to ICU, and increased hospital length of stay.

Does Difficult Mask Ventilation Predict Obstructive Sleep Apnea? A Prospective Pilot Study to Identify the Prevalence of OSA in Patients with Difficult Mask Ventilation Under General Anesthesia

Patients with difficult mask ventilation under general anesthesia were subsequently evaluated with nocturnal polysomnography (PSG) to determine the presence of a sleep-related breathing disorder. Of 10 patients who underwent PSG, 9 demonstrated OSA and 1 had an elevated RDI (> 5) with excessive daytime sleepiness (categorized as upper airways resistance syndrome). This study suggests that anesthesiologists can identify individuals de novo with increased risk of OSA based on the difficulty of mask ventilation during surgical procedures.