Cost-comparison study of reusable and disposable rhinolaryngoscopes in a large English teaching hospital.

OBJECTIVE: This study aimed to compare the cost per use of video-rhinolaryngoscopy using reusable and disposable devices in a tertiary referral centre. METHODS: A cost-comparison study was performed that utilised retrospective cost data and prospective utilisation data to compare the total costs of using reusable video-rhinolaryngoscopes versus a single-use alternative. RESULTS: It was estimated that 4776 and 1821 procedures were performed annually with reusable and disposable video-rhinolaryngoscopes, respectively. The cost per use was £66.61 for reusable devices versus £150.00 for disposable devices. The break-even point (i.e. when cost per use was equal, occurred at 1374 procedures per year). Thereafter, it was cheaper to use reusable devices. CONCLUSION: Disposable rhinolaryngoscopes may present a cheaper solution to services with low rates of rhinolaryngoscope utilisation. However, for larger services considering replacement of their reusable rhinolaryngoscopes with disposable units, it is likely that the recurring costs will be prohibitive in the medium to long term.

Management of postoperative pain in maxillofacial surgery.

In this review we describe the evidence base for postoperative analgesia after maxillofacial surgery. We discuss the implications of poorly managed pain, risk factors for the development of severe pain, and pharmacological and non-pharmacological analgesic strategies to manage it.

Validity and reliability of an objective structured assessment tool for performance of ultrasound-guided regional anaesthesia.

BACKGROUND: We examined the validity and reliability of the previously developed criterion-referenced assessment checklist (AC) and global rating scale (GRS) to assess performance in ultrasound-guided regional anaesthesia (UGRA). METHODS: Twenty-one anaesthetists' single, real-time UGRA procedures (total: 21 blocks) were assessed using a 22-item AC and a 9-item GRS scored on 3-point and 5-point Likert scales, respectively. We used one-way analysis of variance to compare the assessment scores between three groups (Group 1: ≤30 blocks in the preceding year; Group 2: 31-100; and Group 3: >100). The concurrent validity was evaluated using Pearson's correlation (r). We calculated Type A intra-class correlation coefficient using an absolute-agreement definition in two-way random effects model, and inter-rater reliability using an absolute agreement between raters. The inter-item consistency was assessed by Cronbach's α. RESULTS: The greater UGRA experience in the preceding year was associated with better AC [F (2, 18) 12.01; P<0.001] and GRS [F (2, 18) 7.44; P=0.004] scores. There was a strong correlation between the mean AC and GRS scores [r=0.73 (P<0.001)], and a strong inter-item consistency for AC (α=0.94) and GRS (α=0.83). The intra-class correlation coefficient (95% confidence interval) and inter-rater reliability (95% confidence interval) for AC were 0.96 (0.95-0.96) and 0.91 (0.88-0.95), respectively, and 0.93 (0.90-0.94) and 0.80 (0.74-0.86) for GRS. CONCLUSIONS: Both assessments differentiated between individuals who had performed fewer (≤30) and many (>100) blocks in the preceding year, supporting construct validity. It also established concurrent validity and overall reliability. We recommend that both tools can be used in UGRA assessment.

Management of the airway in maxillofacial surgery: part 2.

Prediction of the difficulty of an airway is unreliable, and failure of one technique of management increases the likelihood of failure of subsequent interventions. Part 2 of this review describes strategies to avoid or mitigate the impact of failure, and the associated airway-related morbidity and mortality.

Management of the airway in maxillofacial surgery: part 1.

In part 1 of this review of management of the airway in maxillofacial surgery we discuss preoperative assessment of the airway, and the practical means to deal with difficulties. We review the evidence for videolaryngoscopy and flexible indirect laryngoscopy, together with surgical access to the airway including tracheostomy, cricothyroidotomy, and submental intubation.

Retention of laryngoscopy skills in medical students: a randomised, cross-over study of the Macintosh, A.P. Advance(™) , C-MAC(®) and Airtraq(®) laryngoscopes.

In addition to being effective and easy to learn how to use, the ideal laryngoscope should be associated with minimal reduction in skill performance during gaps in practice over time. We compared the time taken to intubate the trachea of a manikin by novice medical students immediately after training, and then after 1 month, with no intervening practice. We designed a two-period, four-group, randomised, cross-over trial to compare the Macintosh, Venner(™) A.P. Advance(™) with difficult airway blade, C-MAC(®) with D-Blade and Airtraq(®) with wireless video-viewer. A bougie was used to aid intubation with the Macintosh and the C-MAC. After training, there was no significant difference in median (IQR [range]) intubation time using the videolaryngoscopes compared with the Macintosh, which took 30 (26.5-35 [12-118])s. One month later, the intubation time was longer using the C-MAC (41 (29.5-52 [20-119])s; p = 0.002) and A.P. Advance (40 (28.5-57.5 [21-107])s; p = 0.0003)m compared with the Macintosh (27 (21-29 [16-90])s); there was no difference using the Airtraq (27 (20.5-32.5 [15-94])s; p = 0.258) compared with the Macintosh. While skill acquisition after a brief period of learning and practice was equal for each laryngoscope, performance levels differed after 1 month without practice. In particular, the consistency of performance using the C-MAC and A.P. Advance was worse compared with the Macintosh and the Airtraq. While the clinical significance of this is doubtful, we believe that reliable and consistent performance at laryngoscopy is desirable; for the devices that we tested, this requires regular practice.

Cognitive Aids in Medicine Assessment Tool (CMAT): preliminary validation of a novel tool for the assessment of emergency cognitive aids.

Applying human factors principles to the design of clinical emergency guidelines is important. The UK Civil Aviation Authority uses a Checklist Assessment Tool for evaluating the content and usability of emergency drills before introduction into service on aircraft. We hypothesised that this model could be used to develop a generic medical tool. A three-stage modified Delphi process was used to adapt the above tool for use in designing medical emergency guidelines. The resulting Cognitive aids in Medicine Assessment Tool was then used to score and rank seven published difficult airway guidelines; the scores were used to assess its validity and reliability. Pearson's rank coefficient between these scores and scores from independent assessors was 0.89 (p = 0.007). Internal consistency, as assessed by Cronbach's alpha, was 0.74, 0.96 and 0.72 for the tool's three constituent domains of physical characteristics, content and layout/format, respectively. Inter-rater reliability, as assessed by Cohen's kappa, ranged from 0.33 to 0.72. The adoption of our tool has the potential to improve the usability of medical emergency guidelines.

Cost comparison of re-usable and single-use fibrescopes in a large English teaching hospital.

A number of studies in the U.S.A. and mainland Europe have described the costs of fibreoptic tracheal intubation. However, no such data from the UK appear available. We performed a cost assessment of fibreoptic intubation, using re-usable (various devices from Olympus, Acutronic and Karl Storz) and single-use (Ambu aScope) fibrescopes, at the Queens Medical Centre, Nottingham, U.K., between 1 January 2009 and 31 March 2014. The total annual cost of fibreoptic intubation with re-usable fibrescopes was £46,385. Based on 141 fibreoptic intubations per year, this equated to £329 per use, an average dominated by repair/maintenance costs (43%) and capital depreciation costs (42%). In comparison, the total annual cost of using single-use fibrescopes for the same work would have been around £200 per use. The analysis enabled us to develop a generic model, wherein we were able to describe the relationship between total cost of use vs number of uses for a fibrescope. An 'isopleth' was identified for this relationship: a line that joined all the points where the cost of re-usable vs single-use fibrescopes was equal. It appears cheaper to use single-use fibrescopes at up to 200 fibreoptic intubations per year (a range commensurate with normal practice) even when the repair rate for re-usable fibrescopes is low. Any centre, knowing its fibrescope use and repair rate, can plot its data similarly to help ascertain which of the re-usable or single-use fibrescope represents better value.

Cadaveric study of movement of an unstable atlanto-axial (C1/C2) cervical segment during laryngoscopy and intubation using the Airtraq(®) , Macintosh and McCoy laryngoscopes.

Concern that laryngoscopy and intubation might create or exacerbate a spinal cord injury has generated extensive research into cervical spinal movement during laryngoscopy. We performed a randomised trial on six cadavers, using three different laryngoscopes, before and after creating a type-2 odontoid peg fracture. Our primary outcome measure was the change in the space available for the spinal cord at the C1/2 segment measured by cinefluoroscopy. Tracheal intubation was performed using a minimal view of the glottis, a bougie, and manual in-line stabilisation. In a cadaveric model of type-2 odontoid fracture, the space available for the cord was preserved in maximum flexion and extension, and changed little on laryngoscopy and intubation.

Responsiveness of the EQ-5D health-related quality-of-life instrument in assessing low back pain.

OBJECTIVE: To compare the responsiveness of the EuroQol five-dimensional questionnaire (EQ-5D) generic quality-of-life instrument with that of specific instruments-the Brief Pain Inventory (BPI) and the Oswestry Disability Index (ODI)-in assessing low back pain. METHODS: Data were obtained from a group of patients receiving epidural steroid injections. We assessed responsiveness by using correlation, by estimating standardized response means, by receiver operating characteristic curve analysis, and by comparing the minimum clinically important differences peculiar to each of the instruments. RESULTS: ODI, BPI, and EQ-5D index scores, and changes in scores, were found to be correlated. Estimated standardized response means and receiver operating characteristic curve analysis suggested lower responsiveness for the EQ-5D index score. Clinically significant categories of mild, moderate, and severe BPI pain intensity translated into progressively and significantly lower mean EQ-5D index scores. An increase or a decrease in severity level reported on any of the five EQ-5D dimensions was associated with significant changes (with appropriate signs) in the condition-specific scores. No change in severity in any EQ-5D dimension was associated with no change in the specific scores. Significant changes in the EQ-5D index scores were associated with clinically important changes in the ODI and BPI scores. Correlation between index scores and responses on EQ-5D's visual analogue scale was only moderate. CONCLUSIONS: The EQ-5D index is less responsive than instruments specific to pain measurement, although it is capable of indicating clinically important changes. The lower responsiveness arises from EQ-5D's more limited gradation of severity and its multidimensionality.

Novice performance of ultrasound-guided needle advancement: standard 38-mm transducer vs 25-mm hockey stick transducer.

The optimal method to develop expertise in ultrasound-guided regional anaesthesia is unknown. Studies of laryngoscopic expertise in novices demonstrate that the choice of laryngoscope affects performance. In this study, we aimed to compare the effect of two different linear array transducers (38-mm standard vs 25-mm hockey stick) on novice performance of ultrasound-guided needle advancement. Following randomisation, participants watched a video model of expert performance of ultrasound-guided needle advancement. Recruits performed the modelled task on a turkey breast model. The median (IQR [range]) composite error score was statistically significantly larger for participants in the hockey stick transducer group compared with the standard transducer group; 10.0 (7.3-14.3 [2.5-29.0]) vs 7.5 (4.5-10.0 [2.0-28.0]) respectively, (p = 0.01). This study has demonstrated that performance of ultrasound-guided needle advancement by novice operators after simple video instruction is better (as assessed using a composite error score) with a standard 38-mm transducer than with a 25-mm hockey stick transducer.

A pilot study of the dose-response of caudal methylprednisolone with levobupivacaine in chronic lower back pain.

The question as to what constitutes the ideal epidural steroid injection remains unresolved. We performed a prospective, randomised, double-blind, AB/BA 2 × 2 crossover study of caudal 40 vs 80 mg methylprednisolone acetate (in 20 ml levobupivacaine 0.125%) in outpatients with chronic low back pain. Data from 33 participants were analysed. The Oswestry Disability Index improved in both dose groups over time following injection. However, a statistically significant improvement was only observed in the 40 mg methylprednisolone acetate group (40 mg: p < 0.001; 80 mg: p = 0.33). There was no statistically significant difference between the dose groups in change in the Oswestry Disability Index with respect to time. Methylprednisolone acetate 40 mg appears to be as effective as 80 mg in improving disability associated with chronic low back pain, and should be considered in preference to the 80 mg dose for outpatients with chronic low back pain attending for repeat caudal steroid injection.

Indices of pulmonary oxygenation in pathological lung states: an investigation using high-fidelity, computational modelling.

BACKGROUND: Existing indices of pulmonary oxygenation vary misleadingly with external factors such as inspired oxygen fraction (FI(O2)), arterial carbon dioxide tension (PaCO2), and haemoglobin (Hb). Previous work suggested that some indices may be acceptably useful in particular scenarios such as acute respiratory distress syndrome (ARDS) or where FI(O2)>60%. However, it is not possible to identify such scenarios in most clinical contexts; therefore we aimed to examine the induced variability of existing indices in a population of patients with a variety of lung defects. METHODS: We configured nine virtual patients within the Nottingham Physiology Simulator, each with a unique pulmonary configuration but identical arterial blood gases at FI(O2) 30%, PaCO2 6.0 kPa and Hb 8.0 g dl(-1). Factors (FI(O2), P(CO2), Hb) were varied independently and indices of oxygenation including calculated venous admixture (Qs/Qt), arterial oxygen tension (PaO2/FI(O2)), arterio-alveolar gas tension gradient (PA-aO2), and respiratory index (PA-aO2/PaO2) were recorded. RESULTS: All indices varied with FI(O2), with greatest variation with lung defects having least true (absolute) shunt. Calculated Qs/Qt resisted induced variation best of all the indices, but varied by 30% of its mean value during FI(O2) variation. PaO2/FI(O2) varied greatly, especially during variation in FI(O2) (up to 74% of its average value), and most markedly in defects with little true (absolute) shunt. PaCO2 and Hb variation caused small, consistent changes in all indices that were similar between lung-states. CONCLUSIONS: No existing index of oxygenation adequately describes the severity of gas exchange defect. Existing indices of oxygenation vary with disease severity, disease type, and external factors such as FI(O2). A novel and robust index is needed.