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Wiley Online Library : Anaesthesia
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Evidence for non-random sampling in randomised, controlled trials by Yuhji Saitoh

18. December 2016 - 9:17
Summary

A large number of randomised trials authored by Yoshitaka Fujii have been retracted, in part as a consequence of a previous analysis finding a very low probability of random sampling. Dr Yuhji Saitoh co-authored 34 of those trials and he was corresponding author for eight of them. We found a number of additional randomised, controlled trials that included baseline data, with Saitoh as corresponding author, that Fujii did not co-author. We used Monte Carlo simulations to analyse the baseline data from 32 relevant trials in total as well as an outcome (muscle twitch recovery ratios) reported in several. We also compared a series of muscle twitch recovery graphs appearing in a number of Saitoh's publications. The baseline data in 14/32 randomised, controlled trials had p < 0.01, of which seven p values were < 0.001. Eight trials reported four ratios of the time for the return of muscle activity after neuromuscular blockade, the distributions of which were homogeneous: the p values for the observed Q statistics were 0.0055, 0.031, 0.016 and 0.0071. Comparison of graphs revealed multiple coincident or near-coincident curves across a large number of publications, a finding also inconsistent with random sampling. Combining the continuous and categorical probabilities of the 32 included trials, we found a very low likelihood of random sampling: p = 1.27 × 10−8 (1 in 100,000,000). The high probability of non-random sampling and the repetition of lines in multiple graphs suggest that further scrutiny of Saitoh's work is warranted.

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The effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes and laryngotracheal morbidity in children: a randomised, controlled trial

17. December 2016 - 6:00
Summary

We studied the effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes during tracheal extubation and postoperative laryngotracheal morbidity in children. We randomly allocated 164 children aged 3–13 years undergoing general anaesthesia to one of four groups; tracheal tube cuffs filled with air (n = 41); saline (n = 41); alkalinised lidocaine 0.5% (n = 41); or alkalinised lidocaine 1% (n = 41). Intracuff pressure was monitored and maintained below 20 cmH2O. The mean (SD) increases in systolic blood pressure after tracheal extubation compared with before extubation were 10.9 (10.8) mmHg, 7.3 (17.7) mmHg, 4.1 (10.5) mmHg and 1.9 (9.5) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.021). The mean (SD) increases in diastolic blood pressure after tracheal extubation compared with before extubation were 3.9 (9.7) mmHg, 7.9 (14.6) mmHg, 0.7 (10.4) mmHg and 3.6 (6.9) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.019). The mean (SD) increases in heart rate after tracheal extubation compared with before extubation were 14.2 (7.6) beats.min−1, 15.5 (13.1) beats.min−1, 5.2 (9.6) beats.min−1 and 4.1 (6.6) beats.min−1 in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p < 0.001). The incidence of sore throat 8 h after tracheal extubation was 22.0% in the air-filled group, 9.8% in the saline group, 4.9% in the 0.5% alkalinised lidocaine group and 2.4% in the 1% alkalinised lidocaine group, p = 0.015. We conclude that filling the tracheal tube cuff with alkalinised lidocaine-filled reduces the haemodynamic response to tracheal extubation and postoperative laryngotracheal morbidity in children.

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Neuronal damage biomarkers in the identification of patients at risk of long-term postoperative cognitive dysfunction after cardiac surgery

17. December 2016 - 5:56
Summary

Biomarkers of neurological injury can potentially predict postoperative cognitive dysfunction. We aimed to identify whether classical neuronal damage-specific biomarkers, including brain fatty acid-binding protein, neuron-specific enolase and S100 calcium-binding protein β, as well as plasma-free haemoglobin concentration as a measure of haemolysis, could be used to predict the risk of long-term cognitive decline after coronary artery bypass grafting with or without cardiopulmonary bypass. We assessed cognitive function using the CogState brief computerised cognitive test battery at 3 months and at 15 months after surgery. Blood samples were obtained pre-operatively, after sternal closure, and at 6 h and 24 h postoperatively. We found signs of cognitive decline at 3 months in 15 of 57 patients (26%), and in 13 of 48 patients (27%) at 15 months. Brain fatty acid-binding protein was already significantly higher before surgery in patients with postoperative cognitive dysfunction at 15 months, with pre-operative plasma levels of 22.8 (8.3–33.0 [0–44.6]) pg.ml−1 compared with 9.7 (3.9–17.3 [0–49.0]) pg.ml−1 in patients without cognitive dysfunction. This biomarker remained significantly higher in patients with cognitive decline throughout the entire postoperative period. At 3 months after surgery, high levels of plasma-free haemoglobin at sternal closure were associated with a negative influence on cognitive performance, as were high baseline scores on neuropsychological tests, whereas a higher level of education proved to beneficially influence cognitive outcome. We found that postoperative cognitive dysfunction at 3 months was associated with cognitive decline at 15 months after surgery, and served as a valuable prognostic factor for declines in individual cognitive performance one year later. Classical neuronal injury-related biomarkers were of no clear prognostic value.

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A multicentre snapshot study of the incidence of serious procedural complications secondary to central venous catheterisation

16. December 2016 - 5:40
Summary

Despite the high number of central venous access devices inserted annually, there are limited data on the incidence of the associated procedural complications, many of which carry substantial clinical risk. This point was highlighted in the recently published Association of Anaesthetists of Great Britain and Ireland ‘Safe vascular access 2016’ guidelines. This trainee-led snapshot study aimed to identify the number of central venous catheter insertions and the incidence of serious complications across multiple hospital sites within a fixed two-week period. Secondary aims were to identify the availability of resources and infrastructure to facilitate safe central venous catheter insertion and management of potential complications. Fifteen hospital sites participated, completing an initial resource survey and daily identification of all adult central venous catheter insertions, with subsequent review of any complications detected. A total of 487 central venous catheter insertions were identified, of which 15 (3.1%) were associated with a significant procedural complication. The most common complication was failure of insertion, which occurred in seven (1.4%) cases. Facilities to enable safer central venous catheter insertion and manage complications varied widely between hospitals, with little evidence of standardisation of guidelines or protocols.

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The Universal Anaesthesia Machine (UAM): assessment of a new anaesthesia workstation built with global health in mind

8. December 2016 - 6:50
Summary

The Universal Anaesthesia Machine has been developed as a complete anaesthesia workstation for use in low- and middle-income countries, where the provision of safe general anaesthesia is often compromised by unreliable supply of electricity and anaesthetic gases. We performed a functional and clinical assessment of this anaesthetic machine, with particular reference to novel features and functioning in the intended environment. The Universal Anaesthesia Machine was found to be reliable, safe and consistent across a range of tests during targeted functional testing.

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A feasibility study of awake videolaryngoscope-assisted intubation in patients with periglottic tumour using the channelled King Vision® videolaryngoscope

8. December 2016 - 4:35
Summary

Airway management in patients with periglottic tumour is a high-risk procedure with potentially serious consequences. There is no consensus on how best to secure the airway in this group of patients. We conducted a feasibility study of awake tracheal intubation using a King Vision® videolaryngoscope with a channelled blade in a cohort of 25 patients, with a periglottic tumour requiring diagnostic or radical surgery. We used 10% and 4% lidocaine to topicalise the airway and midazolam and remifentanil for sedation. We recorded the success rate, number of attempts, time to obtain glottic view, time to intubation and complications. Twenty-three of the 25 patients (92%, 95% CI 75–98%) were intubated with the awake videolaryngoscope-assisted technique, with 17/23 (74%, 95% CI 54–87%) intubations achieved at the first attempt. Five patients required two and one patient, three attempts at intubation. Two patients (8%, 95% CI 2–25%) could not tolerate the procedure due to inadequate topical anaesthesia. Median (IQR [range]) times to obtain glottic view and to intubate were 19 (17–22 [10–30]) s and 49 (42–71 [33–107]) s, respectively. Traces of blood in the airway were observed in 4/25 (16%, 95% CI 6–35%) patients. Although airway management in this group of patients was expected to be difficult, successful awake intubation with the King Vision videolaryngoscope was achieved in the majority of patients within less than a minute. This study highlights a number of potential advantages of awake videolaryngoscope-assisted intubation over other awake methods of securing the airway in patients with upper airway obstruction due to periglottic mass.

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Choice of anaesthesia for category-1 caesarean section in women with anticipated difficult tracheal intubation: the use of decision analysis

30. November 2016 - 5:15
Summary

A predicted difficult airway is sometimes considered a contra-indication to rapid sequence induction of general anaesthesia, even in an urgent case such as a category-1 caesarean section for fetal distress. However, formally assessing the risk is difficult because of the rarity and urgency of such cases. We have used decision analysis to quantify the time taken to establish anaesthesia, and probability of failure, of three possible anaesthetic methods, based on a systematic review of the literature. We considered rapid sequence induction of general anaesthesia with videolaryngoscopy, awake fibreoptic intubation and rapid spinal anaesthesia. Our results show a shorter mean (95% CI) time to induction of 100 (87–114) s using rapid sequence induction compared with 9 (7–11) min for awake fibreoptic intubation (p < 0.0001) and 6.3 (5.4–7.2) min for spinal anaesthesia (p < 0.0001). We calculate the risk of ultimate failed airway control after rapid sequence induction to be 21 (0–53) per 100,000 cases, and postulate that some mothers may accept such a risk in order to reduce potential fetal harm from an extended time interval until delivery. Although rapid sequence induction may not be the anaesthetic technique of choice for all cases in the circumstance of a category-1 caesarean section for fetal distress with a predicted difficult airway, we suggest that it is an acceptable option.

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The feasibility of micro-ultrasound as a tool to image peripheral nerves

29. November 2016 - 12:15
Summary

Despite widespread use of ultrasound imaging to guide needle placement, the incidence of transient and permanent nerve damage as a complication of regional anaesthesia has not changed over the last decade. In view of the controversy surrounding intraneural injection there is a need to understand the structural changes caused by subepineural and subperineural needle penetration. Clinical ultrasound machines do not provide adequate anatomical resolution, and anaesthetists have difficulty judging the precise location of the needle tip relative to the epineurium. We studied the suitability of micro-ultrasound imaging (which offers anatomical resolution better than 100 μm) as a tool for viewing neural anatomy and deformation caused by needle insertion. The primary objective was to assess micro-ultrasound imaging as a method to view fascicles within nerves resected from fresh and soft-embalmed cadavers. Secondary objectives were to observe any disruption of the neural anatomy caused by anaesthetic needle penetration, and to assess the integrity of fresh and Thiel method soft-embalmed nerves, after handling and during needle insertion using ultrasound images and histology. We imaged nine nerves from the left and right sides of fresh and soft-embalmed cadavers. A regional block needle was inserted into three median nerves. We identified fascicles > 0.4 mm in width using micro-ultrasound. Subepineural needle placement was associated with denting, rotation and elastic deformation of fascicles, whereas subperineural needle insertion split fascicles permanently.

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An observational study of the macro- and micro-haemodynamic implications of epidural anaesthesia in children

28. November 2016 - 5:30
Summary

The haemodynamic implications of epidural anaesthesia in children are poorly documented. We report macro- and micro-haemodynamic data from an observational study of 25 children ranging from neonates to six-years old, who underwent surgery conducted with a specific combination of monitoring systems. We analysed 90 min of study-related monitoring after epidural catheterisation, with skin incision taking place after around 30 min. We recorded macrohaemodynamic parameters (monitored using LiDCOrapid) including heart rate, mean arterial pressure, cardiac output, stroke volume, systemic vascular resistance and stroke volume variation. Microhaemodynamic parameters (monitored using Invos™) included cerebral and peri-renal oxygenation. Based on the entire 90 min of study-related monitoring, we found significant increases in cardiac output (p = 0.009), stroke volume (p = 0.006) and stroke volume variation (p = 0.008), as well as decreases in systemic vascular resistance (p = 0.007) around 30 min after epidural blockade. There were no significant changes in heart rate, arterial pressure and cerebral or peri-renal oxygenation during these 90 min. Considering that the microhaemodynamic parameters were not affected by the macrohaemodynamic changes, we conclude that autoregulation of the brain and the kidneys was maintained in children under epidural anaesthesia.

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Unexpected motor weakness following quadratus lumborum block for gynaecological laparoscopy

28. November 2016 - 5:20
Summary

Quadratus lumborum block has recently been described as an effective and long-lasting analgesic strategy for various abdominal operations, including gynaecological laparoscopy. Despite evidence that the analgesic effect is mediated by indirect paravertebral block and that local anaesthetic spreads to the lumbar paravertebral space, there have been no reports to date of lower limb motor weakness. We present a patient with unilateral hip flexion and knee extension weakness leading to unplanned overnight admission following lateral quadratus lumborum block with 20 ml levobupivacaine 0.25%. The L2 dermatomal sensory loss and hip flexion weakness suggested spread to either the L2 paravertebral space or to the lumbar plexus, causing weakness of the psoas and iliacus muscles and possibly the quadriceps. The duration of motor block was approximately 18 h. This complication should be considered when performing the block, especially in the setting of day-case surgery.

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Prediction of difficult mask ventilation using a systematic assessment of risk factors vs. existing practice – a cluster randomised clinical trial in 94,006 patients

24. November 2016 - 8:50
Summary

We compared implementation of systematic airway assessment with existing practice of airway assessment on prediction of difficult mask ventilation. Twenty-six departments were cluster-randomised to assess eleven risk factors for difficult airway management (intervention) or to continue with their existing airway assessment (control). In both groups, patients predicted as a difficult mask ventilation and/or difficult intubation were registered in the Danish Anaesthesia Database, with a notational summary of airway management. The trial's primary outcome was the respective incidence of unpredicted difficult and easy mask ventilation in the two groups. Among 94,006 patients undergoing mask ventilation, the incidence of unpredicted difficult mask ventilation in the intervention group was 0.91% and 0.88% in the control group; (OR) 0.98 (95% CI 0.66–1.44), p = 0.90. The incidence of patients predicted difficult to mask ventilate, but in fact found to be easy (‘falsely predicted difficult’) was 0.64% vs. 0.35% (intervention vs. control); OR 1.56 (1.01–2.42), p = 0.045. In the intervention group, 86.3% of all difficult mask ventilations were not predicted, compared with a higher proportion 91.2% in the control group, OR 0.61 (0.41–0.91), p = 0.016. The systematic intervention did not alter the overall incidence of unpredicted difficult mask ventilations, but of the patients who were found to be difficult to mask ventilate, the proportion predicted was higher in the intervention group than in the control group. However, this was at a ‘cost’ of increasing the number of mask ventilations falsely predicted to be difficult.

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Evaluation of three unchannelled videolaryngoscopes and the Macintosh laryngoscope in patients with a simulated difficult airway: a randomised, controlled trial

24. November 2016 - 6:15
Summary

This prospective randomised, controlled trial compares the performance of three unchannelled videolaryngoscopes (KingVision™, Airtraq™, A.P. Advance™ MAC) and the standard Macintosh laryngoscope. With ethics committee approval and written informed consent, 480 patients were included. A difficult airway was created with a cervical collar, limiting mouth opening and neck movement. Primary outcome was first-attempt orotracheal intubation success. Overall success, laryngeal view, intubation difficulty scale, handling, intubation times and side-effects were secondary outcomes. First-attempt success rates were: KingVision 90% (95% CI 83–94%), Airtraq 82% (74–88%), A.P. Advance MAC 49% (40–58%), Macintosh 44% (35–53%; p < 0.001). The 95% confidence interval of first-attempt success rate was thus below 90% for all devices, but the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Also, performance was better with the KingVision and the Airtraq in terms of overall success, laryngeal view, intubation difficulty scale and quality of view. Problems with tube advancement were a frequent cause of intubation failure. In summary, the KingVision and the Airtraq performed better than the A.P. Advance MAC and the Macintosh laryngoscope. Success rates of the unchannelled KingVision and Airtraq were similar to those of their channelled versions reported previously, indicating that performance largely depends on blade design rather than the presence of a channel for tube advancement.

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An evaluation of inpatient morbidity and critical care provision in Zambia

21. November 2016 - 9:26
Summary

The aim of this study was to objectively measure demand for critical care services in a southern African tertiary referral centre. We carried out a point prevalence study of medical and surgical admissions over a 48-h period at the University Teaching Hospital, Lusaka, recording the following: age; sex; diagnosis; Human Immunodeficiency Virus (HIV) status and National Early Warning Score. One-hundred and twenty medical and surgical admissions were studied. Fifty-four patients (45%) had objective evidence of a requirement for critical care review and potential or probable admission to an intensive care unit, according to the Royal College of Physicians (UK) guidelines. A greater than expected HIV rate was also noted; 53 of 75 tested patients (71%). When applied to the estimated 17,496 annual acute admissions, this would equate to 7873 patients requiring critical care input annually at this hospital alone. In contrast to this demand, we identified 109 critical care beds nationally, and only eight at this institution.

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Intensive care medicine in rural sub-Saharan Africa

21. November 2016 - 9:15
Summary

We undertook an audit in a rural Ugandan hospital that describes the epidemiology and mortality of 5147 patients admitted to the intensive care unit. The most frequent admission diagnoses were postoperative state (including following trauma) (2014/5147; 39.1%), medical conditions (709; 13.8%) and traumatic brain injury (629; 12.2%). Intensive care unit mortality was 27.8%, differing between age groups (p < 0.001). Intensive care unit mortality was highest for neonatal tetanus (29/37; 78.4%) and lowest for foreign body aspiration (4/204; 2.0%). Intensive care unit admission following surgery (333/1431; 23.3%), medical conditions (327/1431; 22.9%) and traumatic brain injury (233/1431; 16.3%) caused the highest number of deaths. Of all deaths in the hospital, (1431/11,357; 12.6%) occurred in the intensive care unit. Although the proportion of hospitalised patients admitted to the intensive care unit increased over time, from 0.7% in 2005/6 to 2.8% in 2013/4 (p < 0.001), overall hospital mortality decreased (2005/6, 4.8%; 2013/14, 4.0%; p < 0.001). The proportion of intensive care patients whose lungs were mechanically ventilated was 18.7% (961/5147). This subgroup of patients did not change over time (2006, 16%; 2015, 18.4%; p = 0.12), but their mortality decreased (2006, 59.5%; 2015, 44.3%; p < 0.001).

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Issue Information – Editorial Board

15. November 2016 - 3:02
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