Transnasal humidified rapid‐insufflation ventilatory exchange (THRIVE) vs. facemask breathing pre‐oxygenation for rapid sequence induction in adults: a prospective randomised non‐blinded clinical trial

Transnasal humidified rapid‐insufflation ventilatory exchange (THRIVE) can prolong apnoea time in adults. Therefore, THRIVE used for pre‐oxygenation in rapid sequence induction of anaesthesia could extend safe apnoea time during prolonged laryngoscopy and intubation. In this randomised controlled trial, we compared the lowest peripheral oxygen saturation (SpO₂) during intubation when pre‐oxygenating with either traditional facemask or THRIVE. Eighty adult patients, undergoing rapid sequence induction of anaesthesia for emergency surgery, were randomly allocated to pre‐oxygenation with 100% oxygen with facemask or with THRIVE. Median (IQR [range]) lowest SpO₂ until 1 min after intubation was 99% (97–100 [70–100]%) for the facemask group vs. 99% (99–100 [96–100]%) for the THRIVE group (p = 0.097). Five patients (12.5%) desaturated below 93% when pre‐oxygenated with the facemask vs. none in the THRIVE group (p = 0.019). There were no differences in intubation time or apnoea time between the groups. Median intubation time was 51 (34–66 [22–261]) s in the facemask group vs. 48 (38–63 [10–146]) s in the THRIVE group (p = 0.99). Median apnoea time was 109 (86–142 [37–291]) s and 116 (92–146 [63–249]) s when using facemask and THRIVE, respectively (p = 0.49). No signs of regurgitation of gastric content were detected. The data on desaturation indicate potential benefits of oxygenation with THRIVE for rapid sequence induction compared with facemask pre‐oxygenation.     

Safety and efficacy of rescue flexible bronchoscopic intubation using the Bentson floppy‐tip guidewire via a supraglottic airway in critically ill children

Difficulty in tracheal intubation in paediatric intensive care patients is associated with increased morbidity and mortality. Delays to intubation and interruption to oxygenation and ventilation are poorly tolerated. We developed a safe and atraumatic tracheal intubation technique. A floppy‐tipped guidewire and airway exchange catheter were placed to a pre‐determined length under bronchoscopic guidance while oxygenation and ventilation was maintained via a supraglottic airway device (SAD). We performed a retrospective review of this technique on patients who were either known to have or who had an unexpected difficultly in intubation. We describe the safety and experience of this in a broad range of critically ill children. Thirteen patients, median (IQR [range]) (9.0 (5.0–10.0 [4.0–12.0]) kg and 15.4 (12.1–23.2 [3.3–49.7]) months) underwent emergency tracheal intubation using this technique, after unsuccessful attempts at intubation using standard laryngoscopy blades. All intubations were successful at the first attempt using this technique and no airway trauma or significant clinical deteriorations were recorded.     

A randomised controlled trial comparing the GlideScope® and the Macintosh laryngoscope for double‐lumen endobronchial intubation

Double‐lumen endobronchial tubes are the most common method of achieving lung isolation and one‐lung ventilation during thoracic anaesthesia and surgery. We compared the clinical performance of the Macintosh laryngoscope and the GlideScope^® during endobronchial intubation with a double‐lumen tube. Seventy patients with no predictors for difficult laryngoscopy were allocated randomly to the Macintosh laryngoscope or GlideScope. The time taken for endobronchial intubation with the Macintosh laryngoscope was significantly shorter compared with that taken for the GlideScope, median (IQR [range]) 33 (22–52 [11–438]) s vs 70 (39–129 [21–242]) s, respectively, p = 0.0013. There was no statistical difference in the rate of success at the first attempt (91% vs 83%, respectively). On a numerical rating scale (scored from 0 to 10), the 30 anaesthetists who took part in the study rated endobronchial intubation overall as easier using the Macintosh compared with the GlideScope, 2 (1–3 [0–8]) vs 3 (2–6 [0–10]), respectively, p = 0.003. Postoperative voice changes were also less common in the Macintosh group (8 (22%) vs 17 (58%), p = 0.045). Anaesthetists found the GlideScope more difficult to use than the Macintosh laryngoscope and endobronchial intubation took longer; therefore, we cannot recommend its routine use with double‐lumen tubes in patients who are predicted to have a normal airway.     

A comparison of airway dimensions,measured by acoustic reflectometry and ultrasound before and after general anaesthesia

Changes in airway dimensions can occur during general anaesthesia and surgery for a variety of reasons. This study explored factors associated with postoperative changes in airway dimensions. Patient airway volume was measured by acoustic reflectometory and neck muscle diameter by ultrasound echography in the pre‐ and post‐anaesthetic periods in a total of 281 patients. Neck circumference was also assessed during these periods. A significant decrease in median (IQR [range]) total airway volume (from 63.8 (51.8–75.7 [14.7–103]) ml to 45.9 (33.5–57.2 [6.4–96.3]) ml, p < 0.0001), and a significant increase in muscle diameter (from 4.3 (3.3–5.6 [2.2–9.0]) mm to 5.8 (4.7–7.3 [2.8–1.3]) mm, p < 0.0001) and neck circumference (from 34.0 (32.5–37.0 [29.5–49.0]) cm to 35.0 (33.5–38.0 [30.5–50.5]) cm, p < 0.0001) were observed. It may be possible that changes in airway volume and neck circumference were influenced by surgical duration or peri‐operative fluid management (ρ) = ?0.31 (95% CI ?0.24 to ?0.01), p = 0.0301, ?0.17 (?0.23 to ?0.06), p = 0.0038, 0.23 (0.12–0.34), p < 0.0001, and 0.16 (0.05–0.27), p = 0.0062, respectively). The intra‐oral space can significantly decrease and neck thickness increase after general anaesthesia, and might increase the risk of difficult laryngoscopy and intubation if airway management is required after extubation following general anaesthesia.     

Exploring the limits of prolonged apnoea with high-flow nasal oxygen: an observational study

High-flow nasal oxygen is increasingly used for oxygenation during apnoea. Extending apnoea duration using this technique has mainly been investigated during minor laryngeal surgery, but it is unclear how long it can be administered for before it should be discontinued due to acidosis. We aimed to describe the dynamics of arterial blood gases during apnoeic oxygenation with high-flow nasal oxygen with jaw thrust only, to explore the limits of this technique. We included adult orthopaedic patients scheduled for general anaesthesia. After pre-oxygenation, anaesthesia with neuromuscular blockade was induced and high-flow nasal oxygen (70 l.min⁻¹) was continued with jaw thrust as the only means of airway management, with monitoring of vital signs and arterial blood gas sampling every 5 minutes. Apnoeic oxygenation with high-flow nasal oxygen was discontinued when arterial carbon dioxide tension (PaCO₂) exceeded 12 kPa or pH fell to 7.15. This technique was used in 35 patients and median (IQR [range]) apnoea time was 25 (20–30 [20–45]) min and was discontinued in all patients when pH fell to 7.15. The mean (SD) PaCO₂ increase was 0.25 (0.06) kPa.min⁻¹ but it varied substantially (range 0.13–0.35 kPa.min⁻¹). Mean (SD) arterial oxygen tension was 48.6 (11.8) kPa when high-flow nasal oxygen was stopped. Patients with apnoea time > 25 minutes were significantly older (p = 0.025). We conclude that apnoeic oxygenation with high-flow nasal oxygen resulted in a significant respiratory acidosis that varies substantially on the individual level, but oxygenation was maintained.     

Comparison of forces acting on maxillary incisors during tracheal intubation with different laryngoscopy techniques: a blinded manikin study

Dental trauma is a common complication of tracheal intubation. As existing evidence is insufficient to validly assess the impact of different laryngoscopy techniques on the incidence of dental trauma, the force exerted onto dental structures during tracheal intubation was investigated. An intubation manikin was equipped with hidden force sensors in all maxillary incisors. Dental force was measured while 104 anaesthetists performed a series of tracheal intubations using direct laryngoscopy with a Macintosh blade, and videolaryngoscopy with a C-MAC^®, or the hyperangulated GlideScope^® or KingVision^® laryngoscopes in both normal and difficult airway conditions. A total of 624 tracheal intubations were analysed. The median (IQR [range]) peak force of direct laryngoscopy in normal airways was 21.1 (14.0–32.8 [2.3–127.6]) N and 29.3 (17.7–44.8 [3.3–97.2]) N in difficult airways. In normal airways, these were lower with the GlideScope and KingVision hyperangulated laryngoscopes, with a reduction of 4.6 N (p = 0.006) and 10.9 N (p < 0.001) compared with direct laryngoscopy, respectively. In difficult airways, these were lower with the GlideScope and KingVision hyperangulated laryngoscopes, with a reduction of 9.8 N (p < 0.001) and 17.6 N (p < 0.001) compared with direct laryngoscopy, respectively. The use of the C-MAC did not have an impact on the median peak force. Although sex of anaesthetists did not affect peak force, more experienced anaesthetists generated a higher peak force than less experienced providers. We conclude that hyperangulated videolaryngoscopy was associated with a significantly decreased force exerted on maxillary incisors and might reduce the risk for dental injury in clinical settings.     

A randomised controlled trial comparing transnasal humidified rapid insufflation ventilatory exchange (THRIVE) pre‐oxygenation with facemask pre‐oxygenation in patients undergoing rapid sequence induction of anaesthesia

Pre‐oxygenation is an essential part of rapid sequence induction of general anaesthesia for emergency surgery, in order to increase the oxygen reservoir in the lungs. We performed a randomised controlled trial of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) pre‐oxygenation or facemask pre‐oxygenation in patients undergoing emergency surgery. Twenty patients were allocated to each group. No patient developed arterial oxygen saturation < 90% during attempted tracheal intubation. Arterial blood gases were sampled from an arterial catheter immediately after intubation. The mean (SD) PaO₂ was 43.7 (15.2) kPa in the THRIVE group vs. 41.9 (16.2) kPa in the facemask group (p = 0.722); PaCO₂ was 5.8 (1.1) kPa in the THRIVE group vs. 5.6 (1.0) kPa in the facemask group (p = 0.631); arterial pH was 7.36 (0.05) in the THRIVE group vs. 7.34 (0.06) in the facemask group (p = 0.447). No airway rescue manoeuvres were needed, and there were no differences in the number of laryngoscopy attempts between the groups. In spite of this, patients in the THRIVE group had a significantly longer apnoea time of 248 (71) s compared with 123 (55) s in the facemask group (p < 0.001). Transnasal humidified rapid insufflation ventilatory exchange is a practicable method for pre‐oxygenating patients during rapid sequence induction of general anaesthesia for emergency surgery; we found that it maintained an equivalent blood gas profile to facemask pre‐oxygenation, in spite of a significantly longer apnoea time.     

Lung volume changes in Apnoeic Oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) compared to mechanical ventilation in adults undergoing laryngeal surgery

Background

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) using high-flow 100% oxygen during apnoea has gained increased use during difficult airway management and laryngeal surgery due to a slower carbon dioxide rise compared to traditional apnoeic oxygenation. We have previously demonstrated high arterial oxygen partial pressures and an increasing arterial-alveolar carbon dioxide difference during THRIVE. Primary aim of this study was to characterise lung volume changes measured with electrical impedance tomography during THRIVE compared to mechanical ventilation.

Methods

Thirty adult patients undergoing laryngeal surgery under general anaesthesia were randomised to THRIVE or mechanical ventilation. Subjects were monitored with electrical impedance tomography and repeated blood gas measurement perioperatively. The THRIVE group received 100% oxygen at 70 l min⁻¹ during apnoea. The mechanical ventilation group was intubated and normoventilated with an FiO₂ of 0.4.

Results

Mean age were 48.2 (19.9) and 51.3 (12.3) years, and BMI 26.0 (4.5) and 26.0 (3.9) in the THRIVE and mechanical ventilation group respectively. Mean apnoea time in the THRIVE group was 17.9 (4.8) min. Mean apnoea to end-of-surgery time was 28.1 (12.8) min in the mechanical ventilation group. No difference in delta End Expiratory Lung Impedance was seen between groups over time. In the THRIVE group all but three subjects were well oxygenated during apnoea. THRIVE was discontinued for the three patients who desaturated.

Conclusions

No difference in lung volume change over time, measured by electrical impedance tomography, was detected when using THRIVE compared to mechanical ventilation during laryngeal surgery.

     

A comparison of fibreoptic‐guided tracheal intubation through the Ambu®Aura‐i™, the intubating laryngeal mask airway and the i‐gel™: a manikin study

We compared the Aura‐i ^? , intubating laryngeal mask airway and i‐gel ^? as conduits for fibreoptic‐guided tracheal intubation in a manikin. Thirty anaesthetists each performed two tracheal intubations through each device, a total of 180 intubations. The median (IQR [range]) time to complete the first intubation was 40 (31–50 [15–162]) s, 37 (34–48 [25–75]) s and 28 (22–35 [14–59]) s for the Aura‐i, intubating laryngeal mask airway and i‐gel, respectively. Tracheal intubation through the i‐gel was the quickest (p < 0.01). Resistance to railroading of the tracheal tube over the fibrescope was significantly greater through the Aura‐i compared with the intubating laryngeal mask airway and the i‐gel (p = 0.001). There were no failures to intubate through the intubating laryngeal mask airway or the i‐gel but six intubation attempts through the Aura‐i were unsuccessful, in five owing to a railroading failure and in one owing to accidental oesophageal intubation. We conclude that the Aura‐i does not perform as well as the intubating laryngeal mask airway or the i‐gel as an adjunct for performing fibreoptic‐guided tracheal intubation.     

The effects of prolonged inspiratory time during one‐lung ventilation: a randomised controlled trial

We evaluated the effects of a prolonged inspiratory time on gas exchange in subjects undergoing one‐lung ventilation for thoracic surgery. One hundred patients were randomly assigned to Group I:E = 1:2 or Group I:E = 1:1. Arterial blood gas analysis and respiratory mechanics measurements were performed 10 min after anaesthesia induction, 30 and 60 min after initiation of one‐lung ventilation, and 15 min after restoration of conventional two‐lung ventilation. The mean (SD) ratio of the partial pressure of arterial oxygen to fraction of inspired oxygen after 60 min of one‐lung ventilation was significantly lower in Group I:E = 1:2 compared with Group I:E = 1:1 (27.7 (13.2) kPa vs 35.2 (22.1) kPa, respectively, p = 0.043). Mean (SD) physiological dead space‐to‐tidal volume ratio after 60 min of one‐lung ventilation was significantly higher in Group I:E = 1:2 compared with Group I:E = 1:1 (0.46 (0.04) vs 0.43 (0.04), respectively, p = 0.008). Median (IQR [range]) peak inspiratory pressure was higher in Group I:E = 1:2 compared with Group I:E = 1:1 after 60 min of one‐lung ventilation (23 (22–25 [18–29]) cmH₂O vs 20 (18–21 [16–27]) cmH₂O, respectively, p < 0.001) and median (IQR [range]) mean airway pressure was lower in Group I:E = 1:2 compared with Group I:E = 1:1 (10 (8–11 [5–15]) cmH₂O vs 11 (10–13 [5–16]) cmH₂O, respectively, p < 0.001). We conclude that, compared with an I:E ratio of 1:2, an I:E ratio of 1:1 resulted in a modest improvement in oxygenation and decreased shunt fraction during one‐lung ventilation.     

A comparison of gastric gas volumes measured by computed tomography after high-flow nasal oxygen therapy or conventional facemask ventilation*

High-flow nasal oxygen therapy is increasingly used to improve peri-intubation oxygenation. However, it is unknown whether it may cause or exacerbate insufflation of gas into the stomach. High-flow nasal oxygen therapy is now standard practice in our hospital for adult patients undergoing percutaneous thermal ablation of liver cancer under general anaesthesia with tracheal intubation. We compared gastric gas volumes measured from computed tomography images that had been acquired immediately after intubation in two series of patients: 50 received peri-intubation high-flow nasal oxygen therapy and another 50 received conventional facemask pre-oxygenation and ventilation before intubation and before high-flow nasal oxygen therapy became standard practice in our unit. Median (IQR [range]) gastric gas volume was 24.0 (14.2–59.9 [3–167]) cm³ in the high-flow nasal oxygen therapy group and 23.8 (12.6–38.8 [0–185]) cm³ in the facemask group. There was no difference between the two groups in the volume of gastric gas measured by computed tomography imaging (Mann–Whitney U-test, U = 1136, p = 0.432, n₁ = n₂ = 50). Our results demonstrate that a small volume of gastric gas is commonly present after induction of anaesthesia, but that the use of peri-intubation high-flow nasal oxygen therapy for pre-oxygenation and during apnoea does not increase this volume compared with conventional facemask pre-oxygenation and ventilation. This is clinically relevant, as high-flow nasal oxygen therapy is increasingly being used in a peri-intubation context and in patients at higher risk of aspiration.     

A prospective randomised controlled trial of the LMA Supreme vs cuffed tracheal tube as the airway device during percutaneous tracheostomy

We studied the performance of the LMA Supreme against a cuffed tracheal tube, our standard method of airway control during percutaneous tracheostomy, in 50 consecutive patients from three general critical care units. The primary outcome measure was adequacy of ventilation calculated as the difference in arterial carbon dioxide tension before and after tracheostomy. On an intention‐to‐treat analysis, there was no difference in the increase in arterial carbon dioxide tension between groups, with a median (IQR [range]) for the LMA Supreme of 0.9 (0.3–1.6 [0–2.8]) kPa, and for the tracheal tube of 0.8 (0.4–1.2 [0–2.5]) kPa, p = 0.82. Eight patients out of 25 (32%) crossed over from the LMA Supreme group to the tracheal tube group before commencement of tracheostomy due to airway or ventilation problems, compared with none out of 25 in the tracheal tube group, p = 0.01, and tracheostomy was postponed in two patients in the LMA Supreme group due to poor oxygenation. There were more clinically important complications in the LMA Supreme group compared with the tracheal tube group.     

A cohort evaluation of the paediatric i-gel(™) airway during anaesthesia in 120 children

We studied the i‐gel? in 120 anaesthetised children (92 boys, 28 girls; median (IQR [range]) age (3 ‐7 [0.4 ‐13]) years and weight 19 (15–26 [7–35]) kg) to assess efficacy and usability. Insertion was successful on the first/second/third attempt in 110/8/1 children and failed in one child. Median (IQR [range]) insertion time was 14 (9–16 [6–200]) s. Manual ventilation was possible in all cases, although excess leak precluded a tidal volume above 7 ml.kg^?1 in three children. Fibreoptic inspection through the i‐gel revealed a clear view of the vocal cords in 40 out of 46 cases (87%). Median (IQR [range]) leak pressure was 20 (16–26 [8–30]) cmH₂O. During maintenance of anaesthesia, 16 manipulations were required in 11 children to improve the airway. One child regurgitated without aspirating. Other complications and side effects were infrequent. The i‐gel was inserted without complications, establishing a clear airway and enabling spontaneous and controlled ventilation, in 113 (94%) children. You can respond to this article at http://www.anaesthesiacorrespondence.com     

Tracheal intubation with a camera embedded in the tube tip (Vivasight™)

We studied tracheal intubation in manikins and patients with a camera embedded in the tip of the tracheal tube (Vivasight^?). Four people in two teams and two individuals attempted intubation of a manikin through an i‐gel^? 10 times each. The tracheas of 12 patients with a Mallampati grade of 1 were intubated with a Vivasight tracheal tube through a Berman airway, passed over a Frova^? introducer. All 60 manikin intubations were successful, taking a mean (SD) time of 1.4 (0.5) s. The fastest intubation was performed in 0.5 s. All 12 participants’ tracheas were successfully intubated in a median (IQR [range]) time of 90 (70–120 [50–210]) s. Seven participants complained of a sore throat, comparable with earlier findings for standard laryngoscopy and intubation: five mild; one moderate; and one severe. Tracheal intubation with the Vivasight through the i‐gel or Berman airway is an alternative to existing techniques, against which it should be compared in randomised controlled trials in human participants. It has potential as a fast airway rescue technique.     

Capabilities of a mobile extracorporeal membrane oxygenation service for severe respiratory failure delivered by intensive care specialists

We conducted a single‐centre observational study of retrievals for severe respiratory failure over 12 months. Our intensivist‐delivered retrieval service has mobile extracorporeal membrane oxygenation capabilities. Sixty patients were analysed: 34 (57%) were female and the mean (SD) age was 44.1 (13.6) years. The mean (SD) PaO₂/F_IO₂ ratio at referral was 10.2 (4.1) kPa and median (IQR [range]) Murray score was 3.25 (3.0–3.5 [1.5–4.0]). Forty‐eight patients (80%) required veno‐venous extracorporeal membrane oxygenation at the referring centre. There were no cannulation or extracorporeal membrane oxygenation‐related complications. The median (IQR [range]) retrieval distance was 47.2 (14.9–77.0 [2.3–342.0]) miles. There were no major adverse events during retrieval. Thirty‐seven patients (77%) who received extracorporeal membrane oxygenation survived to discharge from the intensive care unit and 36 patients (75%) were alive after six months. Senior intensivist‐initiated and delivered mobile extracorporeal membrane oxygenation is safe and associated with a high incidence of survival.     

A randomised comparison of free‐handed vs air‐Q™ assisted fibreoptic‐guided tracheal intubation in children < 2 years of age

We prospectively compared free‐handed and air‐Q? assisted fibreoptic‐guided tracheal intubation in children < 2 years of age. Eighty healthy children were enrolled and randomly assigned to a technique (free‐handed or air‐Q assisted) and operator (trainee or attending). Time, number of attempts and manoeuvres required were assessed. There was no difference in median (IQR [range]) time to successful tracheal intubation between the free‐handed (52.2 (34.8–67.7 [19.7–108.0]) s), and the air‐Q assisted (60.3 (45.5–75.1 [28.1–129.0]) s; p = 0.13) groups, or the number of attempts needed. The air‐Q assisted group required fewer manoeuvres to optimise the laryngeal view (median (IQR [range]) 0 (0–1 [0–2])) than the free‐handed group (1 (1–1 [0–3]); p < 0.001). In conclusion, fibreoptic‐guided tracheal intubation times were similar with and without the use of the air‐Q, but supraglottic airway devices may be a consideration for their other practical advantages.     

Aerosol generation with the use of positive pressure ventilation via supraglottic airway devices: an observational study

The amount of aerosol generation associated with the use of positive pressure ventilation via a supraglottic airway device has not been quantified. We conducted a two-group, two-centre, prospective cohort study in which we recruited 21 low-risk adult patients scheduled for elective surgery under general anaesthesia with second-generation supraglottic airway devices. An optical particle sizer and an isokinetic sampling probe were used to record particle concentrations per second at different size distributions (0.3–10 μm) during use as well as baseline levels during two common activities (conversation and coughing). There was a median (IQR [range]) peak increase of 2.8 (1.5–4.5 [1–28.1]) and 4.1 (2.0–7.1 [1–18.2]) times background concentrations during SAD insertion and removal. Most of the particles generated during supraglottic airway insertion (85.0%) and removal (85.3%) were < 3 μm diameter. Median (IQR [range]) aerosol concentration generated by insertion (1.1 (0.6–5.1 [0.2–22.3]) particles.cm⁻³) and removal (2.1 (0.5–3.0 [0.1–18.9]) particles.cm⁻³) of SADs were significantly lower than those produced during continuous talking (44.5 (28.3–70.5 [2.0–134.5]) particles.cm⁻³) and coughing (141.0 (98.3–202.8 [4.0–296.5]) particles.cm⁻³) (p < 0.001). The aerosol levels produced were similar with the two devices. The proportion of easily inhaled and small particles (<1 μm) produced during insertion (57.5%) and removal (57.5%) was much lower than during talking (99.1%) and coughing (99.6%). These results suggest that the use of supraglottic airway devices in low-risk patients, even with positive pressure ventilation, generates fewer aerosols than speaking and coughing in awake patients.     

Manikin study of fibreoptic‐guided intubation through the classic laryngeal mask airway with the Aintree intubating catheter vs the intubating laryngeal mask airway in the simulated difficult airway*

In this randomised crossover manikin study of simulated difficult intubation, 26 anaesthetists attempted to intubate the trachea using two fibreoptic‐guided techniques: via a classic laryngeal mask airway using an Aintree intubating catheter and via an intubating laryngeal mask airway using its tracheal tube. Successful intubation was the primary endpoint, which was completed successfully in all 26 cases using the former technique, and in 5 of 26 cases using the latter (p < 0.0001). The former technique also proved quicker to reach the vocal cords with the fibrescope (median (IQR [range])) time 18 (14–20 [8–44]) s vs 110 (70–114 [30–118]) s, respectively; p = 0.008); and to first ventilation (93 (74–109 [52–135]) s vs 135 (79–158 [70–160]) s, respectively; p = 0.0038)]. We conclude that in simulated difficult intubation, fibreoptic intubation appears easier to achieve using a classic laryngeal mask airway and an Aintree intubating catheter than through an intubating laryngeal mask airway.     

A randomised comparison of the self-pressurised air-Q(TM) intubating laryngeal airway with the LMA Unique(TM) in children*

We conducted a randomised trial comparing the self‐pressurised air‐Q^TM intubating laryngeal airway (air‐Q SP) with the LMA‐Unique in 60 children undergoing surgery. Outcomes measured were airway leak pressure, ease and time for insertion, fibreoptic examination, incidence of gastric insufflation and complications. Median (IQR [range]) time to successful device placement was faster with the air‐Q SP (12 (10–15 [5–18])) s than with the LMA‐Unique (14 (12–17 [6–22]) s; p = 0.05). There were no statistically significant differences between the air‐Q SP and LMA‐Unique in initial airway leak pressures (16 (14–18 [10–29]) compared with 18 (15–20 [10–30]) cmH₂O, p = 0.12), an airway leak pressures at 10 min (19 (16–22 [12–30]) compared with 20 (16–22 [10–30]) cmH₂O, p = 0.81); fibreoptic position, incidence of gastric insufflation, or complications. Both devices provided effective ventilation without the need for airway manipulation. The air‐Q SP is an alternative to the LMA‐Unique should the clinician prefer a device not requiring cuff monitoring during anaesthesia.     

Effect of anaesthetic technique on mortality following major lower extremity amputation: a propensity score‐matched observational study

We investigated whether the type of anaesthesia affects mortality and length of stay after non‐traumatic major lower extremity amputations. A total of 1365 eligible patients who were operated on between 2002 and 2010 were included in the final analysis. Propensity score matching was used to produce 475 matched pairs of patients undergoing operation with either general or regional anaesthesia. We found that 30‐day mortality was significantly greater in the general anaesthesia group compared with the regional anaesthesia group, with an odds ratio (95% CI) of 1.5 (1.0–2.3) in the total matched population and 4.2 (1.3–13.4) in a high‐risk subgroup. The median (IQR [range]) length of postoperative hospital stay was significantly less in the patients of the high‐risk subgroup who had general anaesthesia at 15 (7–21 [1–101]) days compared with 25 days (10–37 [0–78]) for those who had regional anaesthesia (p = 0.027). The results of our study suggest that 30‐day mortality is significantly higher in patients undergoing major lower extremity amputations under general anaesthesia compared with regional anaesthesia.