Low‐flow apnoeic oxygenation for laryngeal surgery: a prospective observational study

Abstract

Summary Laryngeal surgery requires a shared airway and close collaboration between surgeon and anaesthetist in order to optimise operating conditions. Apnoeic oxygenation uses the principle of aventilatory mass flow to maintain oxygenation of pulmonary capillary blood under apnoeic conditions while minimising laryngeal movement. Concerns regarding accumulation of carbon dioxide and resultant acidaemia have limited the use of the technique. We performed a prospective study of low‐flow apnoeic oxygenation for patients undergoing microlaryngoscopy under general anaesthesia in order to evaluate the ability of the technique to maintain oxygenation and determine the resultant rate of carbon dioxide accumulation. Sixty‐four patients undergoing microlaryngoscopy under general anaesthesia were studied between November 2016 and December 2018. Intra‐operative oxygenation was provided via a 10‐French oxygen catheter placed into the trachea delivering oxygen at 0.5–1.0 l.min−1. Data regarding apnoea time, peripheral oxygen saturation and venous blood gas concentrations were recorded. The mean (SD) duration of apnoea was 18.7 (7.2) min. Apnoeic oxygenation allowed successful completion of the surgical procedure in 62/64 patients. Mean (SD) rate of rise of the venous partial pressure of carbon dioxide was 0.15 (0.10) kPa.min−1. Operating conditions were recorded qualitatively as being adequate in all cases. No adverse effects were reported. Low‐flow intra‐tracheal apnoeic oxygenation is a simple, effective and inexpensive technique to maintain oxygenation for laryngeal surgery.

Efficiency of different flows for apneic oxygenation when using high flow nasal oxygen application – a technical simulation

“…Animal experiments that may simulate these effects are not applicable due to completely different airway shapes. Further, since apneic oxygenation was detected long ago [ 15 , 16 ], and applied in multiple studies before [ 17 , 18 ] a technical simulation was to our opinion an acceptable tool to examine the hypotheses. However, as mentioned before, further clinical studies are mandatory to assess gas flows more precisely that on one side may be beneficial in avoiding arterial oxygen desaturation and on the other side do not result in excessive turbulences and thus gas mixing.…”

Transtracheal jet ventilation in a general tertiary hospital: A 7-year audit

“…17 We are experienced in the use of low-flow apnoeic oxygenation via endotracheal catheter in ENT microlaryngoscopy. 18 The use of low-flow apnoeic oxygenation via the transtracheal jet catheter was added to our technique after we found it to be a successful temporising measure during initial surgical debulking of a large, obstructing laryngeal tumour. When there is a major degree of airway obstruction, the repeated high-pressure alarms and automatic interruption of ventilation by the jet ventilator can be sufficient to prevent adequate ventilation and oxygenation of the patient.…”

Apneic laryngeal oxygenation during elective fiberoptic intubation – a technical simulation

“…There is a scientific body of evidence that hypoxemia can be prevented by deep insufflation of oxygen in the laryngeal space and trachea during apneic episodes [9][10][11][12]. Mitterlechner et al reported that oxygen saturation in a test-lung of a manikin remains significantly higher when using a specific laryngoscope blade designed for laryngeal oxygen insufflation, compared to nasal oxygen insufflation [9].…”

“…Mitterlechner et al reported that oxygen saturation in a test-lung of a manikin remains significantly higher when using a specific laryngoscope blade designed for laryngeal oxygen insufflation, compared to nasal oxygen insufflation [9]. Additionally, O'Loughlin et al showed that low-flow tracheal apneic oxygenation during microlaryngoscopy under general anesthesia allowed a successful conduction of surgical procedures and also impeded the increase of carbon-dioxide levels [11]. However, while oxygenation concepts approaching deeper anatomical airway structures are scientifically proven for unexpected difficult airways [13], evidence for apneic laryngeal oxygenation during elective fiberoptic intubation is scarce.…”