A randomised controlled trial comparing fibreoptic-guided tracheal intubation through two supraglottic devices: Ambu® AuraGain™ laryngeal mask and LMA® Fastrach™.

The Ambu®AuraGain™ laryngeal mask (LM) (Ambu A/S, Ballerup, Denmark) is one of the few readily available second-generation supraglottic airway devices (SADs) that offer a conduit for fibreoptic-guided endotracheal intubation. We aimed to compare fibreoptic intubation through this device with the LMA® (laryngeal mask airway) Fastrach™ (Teleflex Medical, Co. Westmeath, Ireland), which has been a recommended dedicated rescue device for the management of the unanticipated difficult airway. This randomised controlled trial compared a previously described fibreoptic score in 116 patients with no known airway pathology, who had asleep fibreoptic endotracheal intubation via either the AuraGain LM or the LMA Fastrach. Time, ease and success rate of SAD and endotracheal tube (ETT) insertion and complications were recorded. The AuraGain LM demonstrated better laryngeal alignment with 29 out of 59 patients in the AuraGain LM (AG) group having a Grade 4 view (only vocal cords visible), compared to 20 out of 54 patients in the LMA Fastrach (FT) group (P=0.003). It allowed significantly quicker and easier ETT intubation when used as a conduit. The AuraGain LM was also quicker to insert compared to the Fastrach LMA. Similar rates of minor complications, such as sore throat and dysphonia occurred in both groups. Our study indicates that when used in patients with complete muscle relaxation and no known airway pathology, the AuraGain LM achieves better laryngeal alignment and quicker, easier and more successful fibreoptic-guided ETT intubation than the Fastrach LMA.

The use of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) for pre-oxygenation in neurosurgical patients: a randomised controlled trial.

This study explored the use of high-flow nasal oxygen (HFNO) in both pre-oxygenation and apnoeic oxygenation in adults who were intubated following a non-rapid sequence induction. Fifty patients were randomised to receive pre-oxygenation via a standard facemask or the Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) device. After five minutes of pre-oxygenation, induction and muscle relaxant agents were given. While waiting for complete paralysis, patients in the standard facemask group received bag-mask ventilation (BMV), whereas patients in the HFNO group received apnoeic oxygenation via the THRIVE device. Serial blood samples for arterial blood gas analysis were taken. Baseline patient and airway characteristics were similar. The median PaO2 after pre-oxygenation was 357 (interquartile range [IQR] 324-450 [range 183-550]) mmHg in the facemask group, compared to 471 (IQR 429-516 [range 185-550]) mmHg in the HFNO group (P=0.01). The median arterial partial pressure of oxygen (PaO2) in the HFNO group decreased after a period of apnoeic oxygenation, and was significantly lower when compared to patients who received BMV in facemask group. The arterial carbon dioxide partial pressure (PaCO2) level after complete paralysis was significantly higher in the HFNO group when compared to the facemask group (median 52 [IQR 48-55 {range 40-65}] versus median 43 [IQR 40-48 {range 35-63}] mmHg, P=0.0005 and P=0.004 respectively). There were no differences in the time to muscle paralysis and time to intubation. Seven patients required use of airway adjuncts during BMV in the facemask group, compared to none in the HFNO group (P=0.004). No complications were observed in either group. HFNO produces a higher PaO2 after pre-oxygenation and safe PaO2 during intubation. However, the subsequent fall in PaO2 and rise in PaCO2 indicates that it is not as effective as BMV in maintaining oxygenation and ventilation following neuromuscular blockade.

A randomised controlled trial comparing high-flow nasal oxygen with standard management for conscious sedation during bronchoscopy.

Traditional conscious sedation for endobronchial ultrasound procedures places patients at risk of desaturation, and high-flow nasal oxygen may reduce the risk. We designed a parallel-group randomised controlled trial of high-flow nasal oxygen at a flow rate of 30-70 l.min-1 via nasal cannulae, compared with standard oxygen therapy at 10 l.min-1 via a bite block in adults planned for conscious sedation for endobronchial ultrasound. The primary outcome was the proportion of patients experiencing desaturation (defined as SpO2 < 90%). Secondary outcomes included oxygen saturation after pre-oxygenation, lowest oxygen saturation during procedure, number of hypoxic episodes, duration of hypoxia, end-procedure end-tidal CO2 , satisfaction scores and complications. Thirty participants were allocated to each group. Baseline patient characteristics, procedure time and anaesthetic agents used were similar between the groups. Desaturation occurred in 4 out of 30 patients allocated to the high-flow nasal oxygen group, compared with 10 out of 30 allocated to the standard oxygenation group, a non-significant difference (p = 0.07) with intention to treat analysis. The difference was significant (p = 0.047) when using a per-protocol analysis. Oxygen saturation after pre-oxygenation and the lowest oxygen saturation during procedure were significantly higher in the high-flow nasal oxygen group compared with the standard oxygenation group; median (IQR [range] 100 (99-100 [93-100]) vs. 98 (97-99 [94-100]), p = 0.0001 and 97.5 (94-99 [77-100]) vs. 92 (88-95 [79-98]), p < 0.001, respectively. There were no differences in other secondary outcomes. Although high-flow nasal oxygen may prevent desaturation due to some causes, it does not protect against hypoxaemia in all circumstances.

Randomised controlled trial comparing the Ambu® aScope™2 with a conventional fibreoptic bronchoscope in orotracheal intubation of anaesthetised adult patients.

Fibreoptic intubation remains an essential skill for anaesthetists to master. In addition to the reusable fibrescope, an alternative disposable videoscope is available (aScope(™)2, Ambu®, Ballerup, Denmark). A total of 60 anaesthetised adult patients were randomised to either having orotracheal intubation using the aScope 2 or a Karl Storz fibrescope. Intubations were performed by experienced operators who were familiar with both devices. The primary outcome was the Global Rating Scale score. Secondary outcomes included intubation success, number of intubation attempts and intubation time. Other subjective outcomes including practicality, useability and image quality were also recorded. There was no significant difference in the Global Rating Scale score, intubation success orintubation time between the aScope 2 or Karl Storz fibrescope. Global Rating Scale scores were three and two in the aScope 2 and Karl Storz groups respectively (P=0.14). All of the other subjective outcomes were similar between the two groups, except that operators found it easier to use the aScope 2 compared to the fibrescope. There was no significant difference in clinical performance between the aScope 2 and the Karl Storz fibreoptic bronchoscope. The aScope's practicality, disposability and recently improved version (aScope(™)3) potentially make it an acceptable alternative to the reusable fibrescope.

Proficient manipulation of fibreoptic bronchoscope to carina by novices on first clinical attempt after specialized bench practice.

BACKGROUND: Proficient manipulation of the fibreoptic bronchoscope is an important component of competent bronchoscopic airway management. We studied the duration of specialized bench training necessary to achieve this proficiency and the subsequent transfer of this psychomotor skill to human subjects. METHODS: Twenty-nine novice endoscopists undertook the training associated with a commercial non-anatomic endoscopic dexterity training system, Dexter. Bronchoscopic driving performance was assessed after each hour of self-directed training, using a global rating scale from 1 (unskilled) to 5 (expert) with a score of 3 linked to proficiency. The scale was applied to anonymized recordings of the endoscopic view as the bronchoscope was manipulated from the mouth to the carina of an anatomic manikin. Once bench proficiency was achieved, the ability of participants to perform the skill on volunteer co-participants was assessed. RESULTS: Ninety-six per cent of participants achieved proficiency on the manikin within 4 h of practice. Ninety-three per cent then drove the bronchoscope proficiently from the mouth to the carina of clinical volunteers on the first attempt. CONCLUSIONS: The endoscopic dexterity required to proficiently drive a bronchoscope in human subjects to an anatomic endpoint relevant to fibreoptic intubation is achievable after 2-4 h of specialized bench training. Training in the local environment may be more conducive to success than in time-limited workshops. Achieving a defined proficiency standard on bench models contributes to the development of basic bronchoscopic competence. This has the potential to protect patients from novice learning curves, optimize clinical education and efficiency, and assist compliance with difficult airway algorithms.

Effectiveness of bupropion as an aid to stopping smoking before elective surgery: a randomised controlled trial.

Smoking is a risk factor for complications during and after surgery, but most smokers are unable to quit before elective surgery. We tested the efficacy of bupropion in improving smoking cessation rates in this setting by enrolling 47 patients from the elective surgery waiting list in a double-blind randomised controlled trial. Patients receiving bupropion had a lower daily cigarette consumption at the time of hospital admission, median (IQR) cigarettes per day: 6 (2-7) vs. 15 (9-20), p = 0.046. They also had a reduction in end-expired carbon monoxide (p = 0.004), a known contaminant of cigarette smoke, and increased arterial oxygen saturation on pulse oximetry (p = 0.011). They were more likely to have stopped smoking at the 3-week visit (p = 0.036), but not at the 6-week visit (p = 0.25) or at the time of hospital admission for surgery (p > 0.99). This study found that smokers waiting for elective surgery are more likely to reduce or stop smoking when treated with bupropion.