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.

Peripheral nerve injury arising in anaesthesia practice.

In this article, we will discuss the pathophysiology of peripheral nerve injury in anaesthetic practice, including factors which increase the susceptibility of nerves to damage. We will describe a practical and evidence-based approach to the management of suspected peripheral nerve injury and will go on to discuss major nerve injury patterns relating to intra-operative positioning and to peripheral nerve blockade. We will review the evidence surrounding particular strategies to reduce the incidence of peripheral nerve injury during nerve blockade, including nerve localisation methods, timing of blocks, needle techniques and design, injection pressure-monitoring and local anaesthetic and adjunct choice.

Spinal cord injury arising in anaesthesia practice.

Spinal cord injury arising during anaesthetic practice is a rare event, but one that carries a significant burden in terms of morbidity and mortality. In this article, we will review the pathophysiology of spinal cord injury. We will then discuss injuries relating to patient position, spinal cord hypoperfusion and neuraxial techniques. The most serious causes of spinal cord injury - vertebral canal haematoma, spinal epidural abscess, meningitis and adhesive arachnoiditis - will be discussed in turn. For each condition, we draw attention to practical, evidence-based measures clinicians can undertake to reduce their incidence, or mitigate their severity. Finally, we will discuss transient neurological symptoms. Some cases of spinal cord injury during anaesthesia can be ascribed to anaesthesia itself, arising as a direct consequence of its conduct. The injury to a spinal nerve root by inaccurate and/or incautious needling during spinal anaesthesia is an obvious example. But in many cases, spinal cord injury during anaesthesia is not caused by, related to, or even associated with, the conduct of the anaesthetic. Surgical factors, whether direct (e.g. spinal nerve root damage due to incorrect pedicle screw placement) or indirect (e.g. cord ischaemia following aortic surgery) are responsible for a significant proportion of spinal cord injuries that occur concurrently with the delivery of regional or general anaesthesia.

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.

Ultrasound-guided spinal accessory nerve blockade in the diagnosis and management of trapezius muscle-related myofascial pain.

We report the first description of ultrasound-guided spinal accessory nerve blockade using single-shot and subsequently continuous infusion (via a perineural catheter) local anaesthetic techniques, for the diagnosis and treatment of myofascial pain affecting the trapezius muscle. A 38-year-old man presented with a two-year history of incapacitating left suprascapular pain after a fall onto his outstretched hand. The history and clinical examination was suggestive of myofascial pain affecting the trapezius muscle. This had been unresponsive to pharmacological therapy, physiotherapy or suprascapular nerve blockade. Following identification of the spinal accessory nerve in the posterior triangle of the neck, we performed ultrasound-guided nerve blocks, first using a single injection of local anaesthetic and subsequently using a continuous infusion via a perineural catheter, to block the nerve and temporarily relieve the patient's pain. We have demonstrated that the spinal accessory nerve is identifiable in the posterior triangle of the neck and can be blocked successfully using ultrasound guidance. This technique can aid the diagnosis and treatment of myofascial pain originating from the trapezius muscle.

Effect of preoperative multimedia information on perioperative anxiety in patients undergoing procedures under regional anaesthesia.

BACKGROUND: Provision of preoperative information can alleviate patients' anxiety. However, the ideal method of delivering this information is unknown. Video information has been shown to reduce patients' anxiety, although little is known regarding the effect of preoperative multimedia information on anxiety in patients undergoing regional anaesthesia. METHODS: We randomized 110 patients undergoing upper or lower limb surgery under regional anaesthesia into the study and control groups. The study group watched a short film (created by the authors) depicting the patient's in-hospital journey including either a spinal anaesthetic or a brachial plexus block. Patients' anxiety was assessed before and after the film and 1 h before and within 8 h after their operation, using the Spielberger state trait anxiety inventory and a visual analogue scale. RESULTS: There was no difference in state and trait anxiety between the two groups at enrollment. Women had higher baseline state and trait anxiety than men (P=0.02). Patients in the control group experienced an increase in state anxiety immediately before surgery (P<0.001), and patients in the film group were less anxious before operation than those in the control group (P=0.04). After operation, there was a decrease in state anxiety from baseline in both groups, but patients in the film group were less anxious than the control group (P=0.005). CONCLUSIONS: Preoperative multimedia information reduces the anxiety of patients undergoing surgery under regional anaesthesia. This type of information is easily delivered and can benefit many patients.

New technologies in nerve location.

Regional anaesthesia is undergoing a renaissance, perhaps assisted by the introduction of (and enthusiasm for) ultrasound-guided regional anaesthesia into clinical practice. This article summarises the technology and principles of ultrasound imaging in anaesthesia and describes the development of three-dimensional ultrasound imaging, considering whether this new technology has an application in regional anaesthesia.

Pitfalls of ultrasound guided vascular access: the use of three/four-dimensional ultrasound.

The use of ultrasound guidance for central venous access is widespread and was recommended as the technique of choice by The National Institute of Clinical Excellence in the UK in 2002. However, complications have been reported using this technique. In this article we review the technique of two-dimensional ultrasound needle guidance and the errors that can occur. We then discuss the development of three- and four-dimensional ultrasound and describe our experiences using this imaging modality in simulated and actual needle-guidance. We discuss the potential advantages for clinicians utilising this newer form of ultrasound imaging for central venous access.

Survey of intrathecal opioid usage in the UK.

BACKGROUND AND OBJECTIVE: Intrathecal opioids are now used routinely in the UK for intra- and postoperative analgesia. The opioids of choice have altered over recent years and the dosage regimens used can vary between institutions. Concerns over safety have been reduced probably because much lower doses of opioids are now being used. This survey explored the practice of intrathecal opioid usage in the UK. METHODS: We sent a questionnaire survey to 270 anaesthetic departments and received 199 replies, a response rate of 73.7%. RESULTS: Intrathecal opioids were used in 175 (88.4%) departments. Of these departments, 107 (61.1%) had local guidelines or protocols in place. Opioids such as diamorphine (used in 136 (78.2%) of departments) and fentanyl (129 (74.1%)) with a shorter duration of action are now more commonly used than morphine (37 (21.3%)) for intrathecal analgesia. In 96 (54.5%) departments, patients were nursed on regular surgical wards following administration of spinal opioids. CONCLUSIONS: The use of low-dose lipophilic intrathecal opioids for postoperative analgesia is widespread in the UK. Patients are commonly nursed in low-dependency post-anaesthetic care areas. The low incidence of adverse events reported by the respondents along with the popularity of the technique suggests that low-dose spinal opioid administration is safe.

Predicting patients' responses to changes in mechanical ventilation: a comparison between physicians and a physiological simulator.

We compared the accuracy and reliability of a validated, physiological simulator and six intensive care specialists in predicting changes in arterial oxygen tension (PaO(2)), arterial carbon dioxide tension (PaCO(2)) and pH following adjustment of mechanical ventilation. Twenty-five data sets were collected before and after routine alterations in ventilator settings. Fractional inspired oxygen was adjusted in all patients and minute volume was adjusted in 13 patients. The simulator was more accurate and consistent than all the physicians in predicting the magnitude of PaO(2) and pH change. The simulator had a larger bias in estimating the magnitude of change of PaCO(2) than four of the physicians, but was more consistent than all but one of the physicians. The simulator may prove to be a useful tool in the management of mechanical ventilation. Incorporation into mechanical ventilators in a passive predictive role or an active 'closed-loop' ventilation management system are potential roles for physiological simulation.