The effect of metrics-based feedback on acquisition of sonographic skills relevant to performance of ultrasound-guided axillary brachial plexus block.

The objective of this study was to examine the effect of metrics-based vs. non-metrics-based feedback on novices learning predefined competencies for acquisition and interpretation of sonographic images relevant to performance of ultrasound-guided axillary brachial plexus block. Twelve anaesthetic trainees were randomly assigned to either metrics-based-feedback or non-metrics-based feedback groups. After a common learning phase, all participants attempted to perform a predefined task that involved scanning the left axilla of a single volunteer. Following completion of the task, all participants in each group received feedback from a different expert in regional blocks (consultant anaesthetist) and were allowed to practise the predefined task for up to 1 h. Those in the metrics-based feedback group received feedback based on previously validated metrics, and they practised each metric item until it was performed satisfactorily, as assessed by the supervising consultant. Subsequently, each participant attempted to perform ultrasonography of the left axilla on the same volunteer. Two trained consultant anaesthetists independently scored the video recording pre- and post-feedback scans using the validated metrics list. Both groups showed improvement from pre-feedback to post-feedback scores. Compared with participants in the non-metrics-based feedback group, those in the metrics-based feedback group completed more steps: median (IQR [range]) 18.8 (1.5 [17-20]) vs. 14.3 (4.5 [11-18.5]), p = 0.009, and made fewer errors 0.5 (1 [0-1.5]) vs. 1.5 (2 [1-6]), p = 0.041 postfeedback. In this study, novices' sonographic skills showed greater improvement when feedback was combined with validated metrics.

Construct validity of a novel assessment tool for ultrasound-guided axillary brachial plexus block.

The purpose of this study was to examine the construct validity and reliability of a novel metrics-based assessment tool, previously developed for ultrasound-guided axillary brachial plexus block. Five expert and eight novice anaesthetists performed a total of 18 ultrasound-guided axillary brachial plexus blocks on the same number of patients. A trained investigator video-taped procedures according to a pre-defined protocol. Two trained consultant anaesthetists independently scored the videos using the assessment tool. Compared with novices, experts completed more steps (mean 41.0 vs. 33.1, p = 0.001), had fewer procedural errors (2.8 vs. 7.9, p < 0.0001), had fewer critical errors (0.8 vs. 1.3, p = 0.030), and fewer total errors (3.5 vs. 9.1, p < 0.0001). The mean inter-rater reliability for scoring of experts' performance was 0.91, for novices' performance was 0.84, and for all performance combined (n = 18) was 0.88. This assessment tool is valid, and discriminates reliably between expert and novice performance for placement of ultrasound-guided axillary brachial plexus blocks.

Congenital renal arteriovenous malformation in pregnancy presenting with hypertension.

Congenital renal arteriovenous malformations (AVMs) are rare, with approximately 50 cases reported in the literature. Typically, they are small (1 to 2 cm) and the majority present with hematuria and symptoms and signs of congestive heart failure. Review of the literature revealed only 4 cases reported in pregnant patients and their presentation was with hematuria and rupture of the AVM. We present a case of a young female patient with a 6 cm congenital renal AVM who was otherwise asymptomatic until her first pregnancy, when she developed and presented with symptoms of hypertension and an abdominal bruit. Her symptoms persisted postpartum. Hematuria and rupture of the AVMs were not part of her clinical course. A partial nephrectomy was curative.

Use of synthetic material in sling surgery: a minimally invasive approach.

Traditionally, autologous material has been favored over synthetic material in the construction of pubovaginal slings for the treatment of female stress urinary incontinence (SUI). This preference arose largely because of concern about an increased incidence of infection or sling erosion when synthetic materials are used. However, when care is taken to minimize the amount of synthetic material, reduce total operative time, and limit exposure of the material to the operative field, female SUI can be treated effectively with synthetic material with an acceptably low complication rate. Furthermore, utilization of slings constructed with artificial graft material can be minimally invasive, cost effective, and well tolerated.

Experience with the penile prosthesis and artificial urinary sphincter.

The therapy of two common urologic problems, erectile dysfunction and urinary stress incontinence, has been revolutionized over the last 20 years by the incorporation of principles of hydraulic mechanics into the field of silicone prosthesis implantation. The inflatable penile prosthesis is surgically implanted into men with impotence due to organic or psychogenic etiology. The artificial urinary sphincter has found widespread use in males and females in both the adult and pediatric populations with stress incontinence from a variety of causes. Associated with these popular devices are various complications relating to the anatomic site as well as the host's immunologic response. The use of these implants, as well as the technologic innovations resulting from various adverse effects, are reviewed herein.

The use of remifentanil in the anaesthetic management of patients undergoing adrenalectomy: a report of three cases.

The use of remifentanil has been recommended because of its ability to minimise the hypertensive response to tracheal intubation and surgical stimulation in various types of surgery. We describe the use of remifentanil in the anaesthetic management of three cases of open adrenalectomy, two for removal of a phaeochromocytoma and one for removal of an adrenal cortical tumour. Although the use of remifentanil was associated with no adverse events in the patient undergoing resection of the adrenal cortical tumour, its administration was associated with significant hypotension and bradycardia in the two phaeochromocytoma patients, who had both been given alpha- and beta-adrenergic receptor blocking drugs before surgery. It did not prevent the increases in blood pressure or plasma catecholamine levels associated with tumour manipulation in these patients. Remifentanil should therefore be used with caution in patients receiving alpha- and beta-adrenergic receptor blocking drugs. The use of potent vasodilators may still be necessary during tumour manipulation even if remifentanil is being infused.

The Gore-tex sling procedure for female sphincteric incontinence: indications, technique, and results.

We constructed a pubovaginal sling using the Gore-tex Soft Tissue Patch and 2-0 polytetrafluoroethylene (PTFE) suspension suture and placed it in 122 consecutive incontinent women with urethral hypermobility and/or intrinsic sphincter deficiency. We performed a retrospective outcome analysis using a questionnaire-based telephone survey. The mean follow-up period was 24.4 months. Stress incontinence was cured in 88% of patients (equally effective in type II and type III incontinence), de novo postoperative urinary frequency occurred in 32% of cases, and preoperative urinary frequency resolved postoperatively in 51% of patients. Significant urinary obstruction occurred in 5% of patients. Vaginal granulation tissue with exposed sling occurred in 4% of patients. There was no urethral or bladder erosion. The treatment of female stress incontinence with a PTFE sling is effective and durable with minimal complications. Furthermore, this technique addresses many of the presumed technical shortcomings of endoscopic needle suspensions.

Changing trends in the management of prostatic disease in a single private practice: a 5-year followup.

Evaluation and management services provided by the practicing urologist have changed dramatically during the last few years. This is particularly evident in the approach to men with bladder outlet symptoms and in those in whom the diagnosis of prostate cancer is a distinct possibility. The impact of medical management/observation of symptomatic benign prostatic hypertrophy, as well as the influence of prostate specific antigen, transrectal ultrasound and biopsy, radical prostatectomy and hormonal agents in a 3-man private clinical practice is analyzed. The records of 2,206 patients new to the practice who presented with a variety of prostate-related complaints from July 1, 1986 to June 30, 1991 were reviewed. Of these patients 1,822 (82%) were evaluated for presumed benign bladder outlet symptoms. During year 1 of the study, ending on June 30, 1987, 28% of the presumed benign prostatic hypertrophy patients were treated with transurethral prostatectomy, compared to only 8% of such patients in 1991. In contrast, alpha-blocking agents were used to treat 21% of these patients in 1991. Transrectal ultrasound biopsy currently accounts for 87% of all prostatic biopsies, increasing 4-fold during 5 years. Radical prostatectomy has increased 6-fold during the course of the study. Administration of a luteinizing hormone-releasing hormone analogue has supplanted orchiectomy and estrogen therapy for the treatment of disseminated disease, as witnessed by a 4-fold increase in its use. While it is recognized that these trends are presently applicable to our local metropolitan region, they may reflect practice patterns in similar demographic groups, as well as predict future tendencies nationwide.

Manual versus target-controlled infusions of propofol.

Target-controlled infusion systems have been shown to result in the administration of larger doses of propofol, which may result in delayed emergence and recovery from anaesthesia. The aim of this study was to investigate if this was due to a difference in the depth of hypnosis (using the bispectral index monitoring) between the manual and target controlled systems of administration. Fifty unpremedicated patients undergoing elective surgery were randomly allocated to have their anaesthesia maintained with manual or target-controlled propofol infusion schemes. In both groups, the rate of propofol administration was adjusted according to standard clinical criteria while bispectral index scores were recorded by an observer not involved in the delivery of anaesthesia. The total dose of propofol used was higher in the target controlled group (mean 9.9 [standard deviation 1.6] compared with 8.1 [1.0] mg.kg(-1).h(-1) in the manual group [p < 0.0001]). The times to emergence and recovery end-points were comparable between the two groups. The difference in the total dosage of propofol was mainly due to higher rate of propofol administration in the first 30 min in the target controlled infusion group. The bispectral index scores were lower in the target controlled group during this time, being significantly so over the first 15 min of anaesthesia. We conclude that propofol administration by a target controlled infusion system results in the administration of higher doses of propofol and lower bispectral index values mainly in the initial period of anaesthesia.

Neostigmine antagonism of rocuronium block during anesthesia with sevoflurane, isoflurane or propofol.

PURPOSE: To examine the influence of continuing administration of sevoflurane or isoflurane during reversal of rocuronium induced neuromuscular block with neostigmine. METHODS: One hundred and twenty patients, divided into three equal groups, were randomly allocated to maintenance of anesthesia with sevoflurane, isoflurane or propofol. Neuromuscular block was induced with rocuronium and monitored using train-of-four (TOF) stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. Neostigmine was administered when the first response in TOF had recovered to 25%. At this time the volatile agent administration was stopped or propofol dosage reduced in half the patients in each group (n = 20 in each group). The times to attain TOF ratio of 0.8, and the number of patients attaining this end point within 15 min were recorded. RESULTS: The times (mean +/- SD) to recovery of the TOF ratio to 0.8 were 12.0 +/- 5.5 and 6.8 +/- 2.3 min in the sevoflurane continued and sevoflurane stopped groups, 9.0 +/- 8.3 and 5.5 +/- 3.0 min in the isoflurane continued and isoflurane stopped groups, and 5.2 +/- 2.8 and 4.7 +/- 1.5 min in the propofol continued and propofol stopped groups (P < 0.5-01). Only 9 and 15 patients in the sevoflurane and isoflurane continued groups respectively had attained a TOF ratio of 0.8 within 15 min (P < 0.001 for sevoflurane). CONCLUSIONS: The continued administration of sevoflurane, and to a smaller extent isoflurane, results in delay in attaining adequate antagonism of rocuronium induced neuromuscular block.

Use of methoxamine in the resuscitation of epinephrine-resistant electromechanical dissociation.

We describe three cases of electromechanical dissociation under anaesthesia that were unresponsive to doses of intravenous epinephrine given according to current Advanced Life Support guidelines, but which responded immediately to the intravenous administration of the pure alpha agonist, methoxamine. We suggest a possible mechanism to explain this finding and review the literature on vasopressor drugs used for cardiopulmonary resuscitation during electromechanical dissociation. An intravenous alpha agonist, such as methoxamine 20 mg, should be considered for any case of cardiac arrest secondary to electromechanical dissociation which is unresponsive to epinephrine given according to current guidelines.

Sevoflurane--nitrous oxide anaesthesia supplemented with remifentanil: effect on recovery and cognitive function.

The aim of this study was to compare recovery and psychomotor performance after maintenance of anaesthesia with sevoflurane or sevoflurane supplemented with remifentanil. Sixty-six per cent nitrous oxide was used in all patients. Twenty patients each were randomly allocated to maintenance of anaesthesia with sevoflurane only in concentrations necessary to maintain adequate anaesthesia or with 1.5, 1.0 or 0.5 MAC (end-tidal) of sevoflurane supplemented with remifentanil. The median dosage of remifentanil required in the last three groups was 0.21, 0.25 and 0.34 microg x kg(-1) x min(-1), respectively (p < 0.05). The median times to eye opening were 10.3, 12.7, 11.0 and 6.5 min in the four groups (p < 0.05 between the 0.5 MAC and the other groups) and for orientation 12.1, 14.9, 12.3 and 8.3 min, respectively (p < 0.05 between 0.5 and 1.5 MAC groups). There was no significant difference in the mini-mental state assessment scores or the actual discharge times from the recovery ward among the groups. Significantly greater numbers of patients could perform the critical flicker fusion test at 15 min in the group receiving the lowest concentration of sevoflurane and the highest dosage of remifentanil (p < 0.05). Patients in this group also showed the highest incidence of chest wall rigidity (p < 0.003). We conclude that, while the use of remifentanil with lower concentrations of sevoflurane facilitates early recovery, it does not influence discharge time from recovery ward and may be associated with side-effects such as chest wall rigidity.

Postoperative residual block after intermediate-acting neuromuscular blocking drugs.

The frequency and duration of postoperative residual neuromuscular block on arrival of 150 patients in the recovery ward following the use of vecuronium (n = 50), atracurium (n = 50) and rocuronium (n = 50) were recorded. Residual block was defined as a train-of-four ratio of <0.8. An additional group of 10 patients received no neuromuscular blocking drugs during anaesthesia. The incidence of postoperative residual neuromuscular block was 64%, 52% and 39% after the use of vecuronium, atracurium and rocuronium, respectively. Similar numbers of patients were not able to maintain a sustained head or leg lift for 5 s on arrival in the recovery ward. The mean [range] times to attaining a train-of-four ratio of > or =0.8 after arrival in the recovery ward were 9.2 [1-61], 6.9 [1-24] and 14.7 [1.5-83] min for vecuronium, atracurium and rocuronium, respectively. None of the 10 patients who did not receive neuromuscular blocking drugs had train-of-four ratios <0.8 on arrival in the recovery ward. It is concluded that a large proportion of patients arrive in the recovery ward with a train-of-four ratio <0.8, even with the use of intermediate-acting neuromuscular blocking drugs. Although the residual block is relatively short lasting, it may occasionally be prolonged, requiring close observation and monitoring of such patients in the recovery ward.

Recovery from propofol anaesthesia supplemented with remifentanil.

We have examined the effects on recovery end-points of supplementation of a propofol-based anaesthetic with remifentanil. After induction of anaesthesia with propofol and remifentanil 1.0 microg kg(-1), 15 patients each were randomly allocated to target plasma propofol concentrations of 2, 3, 4 or 5 microg ml(-1) for maintenance of anaesthesia. Remifentanil was administered by infusion for supplementation in doses required for maintenance of adequate anaesthesia. All patients received 50% nitrous oxide in oxygen and ventilation was controlled. The total amount of drugs used and times to different recovery end-points were recorded. Cognitive function was also assessed using a Mini-Mental State questionnaire. The median dose of remifentanil for maintenance of adequate anaesthesia (excluding the initial bolus dose) in the four groups was 0.21, 0.15, 0.11 and 0.13 microg kg(-1) min(-1) respectively (P=0.0026). The median times to eye opening and orientation were shortest in the 2 microg ml(-1) group [6.0 and 6.5 min, 8.5 and 10.8 min, 13.4 and 15.8 min, and 14.2 and 19.5 min respectively in the propofol 2, 3, 4, and 5 microg ml(-1) groups respectively (P<0.001)]. The times to discharge from the recovery ward and the Mini-Mental State scores were not significantly different.

Variability in determination of point of needle insertion in peripheral nerve blocks: a comparison of experienced and inexperienced anaesthetists.

Accurate identification of surface landmarks is essential for the successful performance of peripheral nerve blocks. The variability between experienced and inexperienced practitioners in identifying anatomical landmarks has not been studied previously. Anaesthetists were asked to identify the point of needle insertion for posterior lumbar plexus and sciatic nerve blocks on a volunteer using a standard textbook description. The chosen point for needle insertion was described in terms of X and Y co-ordinates, measured in millimetres, from a zero reference point marked on a volunteer's back. Fifteen experienced and 22 inexperienced anaesthetists took part in the study. The lumbar plexus block mean [range] values for the X, Y co-ordinates were 80 [62-108], 66 [46-86] and 92 [49-150], 62 [0-131] in the experienced and inexperienced groups, respectively. The sciatic nerve block X, Y co-ordinates were 77 [62-99], 70 [49-89] and 68 [29-116], 62 [26-93] in the experienced and inexperienced groups, respectively. The variance for the point of needle insertion was significantly greater in the inexperienced group (p <0.01) for both the lumbar plexus and sciatic nerve blocks. We conclude that with increasing experience, there is decreased variability in determining the point of needle insertion using anatomical landmarks.

Frequency of haemoglobin desaturation with the use of succinylcholine during rapid sequence induction of anaesthesia.

BACKGROUND: The perceived safety of the use of succinylcholine is based on the fact that recovery from its effects will occur before oxygen desaturation occurs in case of failure to intubate or ventilate. The purpose of this study was to examine the incidence of oxygen desaturation after the use of succinylcholine prior to resumption of spontaneous ventilation following four different preoxygenation techniques. METHODS: Twenty-five patients each were randomly allocated to preoxygenation with 4 deep breaths of 100% oxygen or by breathing oxygen for 1, 3 or 5 min following which they received a rapid sequence induction of anaesthesia with fentanyl 1 microg kg(-1), a sleep dose of thiopentone and succinylcholine 1 mg kg(-1). Oxygen saturation was monitored continuously using a finger probe. Ventilation was not assisted unless the saturation decreased to

Identification, localization and functional analysis of imidazoline and alpha adrenergic receptors in canine prostate.

In nonsurgical management of benign prostatic hyperplasia, drugs which interfere with prostate contraction mediated through the alpha-1 adrenergic receptor are used. Clonidine acts at alpha adrenergic and I1-imidazoline receptors. In the present study, we found the Kd for [3H]clonidine binding to I1 sites in canine prostate to be 4 +/- 1 nM; the Bmax was 18 +/- 2 fmol/mg of protein. Inhibition of binding by imidazolines and by brain extracts containing putative endogenous ligand confirmed the identity of these sites as I1-imidazoline. Autoradiographic studies showed localization of both I1 and alpha-2 sites to the glandular epithelium. We sought to determine whether in vivo activation of the I1-imidazoline sites by clonidine mediates its contractile action in canine prostate. Dose-response curves were generated for para-aminoclonidine in the presence of vehicle alone, yohimbine (alpha-2 antagonist), idazoxan (alpha-2/I1/I2 antagonist) and prazosin (alpha-1 antagonist). Prazosin was the most effective antagonist. Yohimbine was less effective and did not effectively discriminate between para-aminoclonidine and phenylephrine, an alpha-1-selective agonist. Idazoxan antagonized para-aminoclonidine, but by not more than 50% at any dose. These results suggest that clonidine is active primarily at alpha-1 receptors on prostate smooth muscle in vivo. Thus the function of the I1 and alpha-2 receptors in the prostate remains to be determined; however, they may be involved in epithelial cell function.