A Broad Diagnostic Battery for Bedside Transcranial Doppler to Detect Flow Changes With Internal Carotid Artery Stenosis or Occlusion

BACKGROUND AND PURPOSE: The authors establish accuracy parameters of a broad diagnostic battery for bedside transcranial Doppler (TCD) to detect flow changes due to internal carotid artery (ICA) stenosis or occlusion. METHODS: The authors prospectively studied consecutive patients with stroke or transient ischemic attack referred for TCD. TCD was performed and interpreted at bedside using a standard insonation protocol. A broad diagnostic battery included major criteria: collateral flow signals, abnormal siphon or terminal carotid signals, and delayed systolic flow acceleration in the middle cerebral artery. Minor criteria included a unilateral decrease in pulsatility index (< or = 0.6 or < or = 70% of contralateral side), flow diversion signs, and compensatory velocity increase. Angiography or carotid duplex ultrasound (CDU) was used to grade the degree of carotid stenosis using North American criteria. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TCD findings were determined. RESULTS: Seven hundred and twenty patients underwent TCD, of whom 517 (256 men and 261 women) had angiography and/or CDU within 8.8 +/- 0.9 days. Age was 63.1 +/- 15.7 years. For a 70% to 99% carotid stenosis or occlusion, TCD had sensitivity of 79.4%, specificity of 86.2%, PPV of 57.0%, NPV of 94.8%, and accuracy of 84.7%. For a 50% to 99% carotid stenosis or occlusion, TCD had sensitivity of 67.5%, specificity of 83.9%, PPV of 54.5%, NPV of 90.0%, and accuracy of 81.6%. TCD detected intracranial carotid lesions with 84.9% accuracy and extracranial carotid lesions with 84.4% accuracy (sensitivity of 88% and 79%, specificity of 85% and 86%, PPV of 24% and 54%, and NPV of 99% and 95%, respectively). The prevalence of the ophthalmic artery flow reversal was 36.4% in patients with > or = 70% stenosis or occlusion. If present, this finding indicated a proximal ICA lesion location in 97% of these patients. CONCLUSIONS: In symptomatic patients, bedside TCD can accurately detect flow changes consistent with hemodynamically significant ICA obstruction; however, TCD should not be a substitute for direct carotid evaluation. Because TCD is sensitive and specific for a > or = 70% carotid stenosis or occlusion in both extracranial and intracranial carotid segments, it can be used as a complementary test to refine other imaging findings and detect tandem lesions.     

Effectiveness of Microporous Polysaccharide Hemospheres for Achieving Hemostasis in Mohs Micrographic Surgery

BACKGROUND: Microporous polysaccharide hemospheres consist of controlled-porosity spherical particles manufactured from bioinert plant polysaccharide. Microporous polysaccharide hemospheres facilitate hemostasis by rapidly absorbing the fluid component of blood, concentrating platelets and clotting factors to accelerate blood clotting. OBJECTIVE: The objective was to compare a microporous polysaccharide hemosphere bandage and electrocautery in achieving hemostasis. METHODS: Twenty-four patients with a total of 48 stages of Mohs micrographic surgery were included. Patients were stratified by whether or not they were taking anticoagulant medications. Within each group, patients were randomized to receive either the microporous polysaccharide hemosphere bandage or electrocautery. Outcomes included bleeding through the dressing (early time point) and active bleeding upon dressing removal (late time point). RESULTS: Nineteen patients not taking anticoagulants had 40 stages, of which 18 received the study bandage and 22 received electrocautery. The remaining 5 patients on anticoagulants had 8 stages, of which 4 received the study bandage and 4 received electrocautery. In both total and subgroup analysis, there was a higher incidence of bleeding through the dressing with the study bandage (p<0.05), but no increase in the incidence of active bleeding upon dressing removal (p>0.05). CONCLUSION: The microporous polysaccharide hemosphere study bandage had an increased incidence of bleeding through the dressing compared to electrocautery, but did not have an increased incidence of active bleeding upon dressing removal.     

The sensitivity of 38 heart rate variability measures to the addition of artifact in human and artificial 24‐hr cardiac recordings

Background

Artifact is common in cardiac RR interval data derived from 24‐hr recordings and has a significant impact on heart rate variability (HRV) measures. However, the relative impact of progressively added artifact on a large group of commonly used HRV measures has not been assessed. This study compared the relative sensitivity of 38 commonly used HRV measures to artifact to determine which measures show the most change with increasing increments of artifact. A secondary aim was to ascertain whether short‐term and long‐term HRV measures, as groups, share similarities in their sensitivity to artifact.

Methods

Up to 10% of artifact was added to 20 artificial RR (ARR) files and 20 human cardiac recordings, which had been assessed for artifact by a cardiac technician. The added artifact simulated deletion of RR intervals and insertion of individual short RR intervals. Thirty‐eight HRV measures were calculated for each file. Regression analysis was used to rank the HRV measures according to their sensitivity to artifact as determined by the magnitude of slope.

Results

RMSSD, SDANN, SDNN, RR triangular index and TINN, normalized power and relative power linear measures, and most nonlinear methods examined are most robust to artifact.

Conclusion

Short‐term time domain HRV measures are more sensitive to added artifact than long‐term measures. Absolute power frequency domain measures across all frequency bands are more sensitive than normalized and relative frequency domain measures. Most nonlinear HRV measures assessed were relatively robust to added artifact, with Poincare plot SD1 being most sensitive.

     

Reducing Persistent Postoperative Pain and Disability 1 Year After Breast Cancer Surgery: A Randomized,Controlled Trial Comparing Thoracic Paravertebral Block to Local Anesthetic Infiltration

Background

The objective of this study was to compare the effect of thoracic paravertebral block (TPVB) and local anesthetic (LA) on persistent postoperative pain (PPP) 1 year following breast cancer surgery. Secondary objectives were to compare the effect on arm morbidity and quality of life.

Methods

Women scheduled for elective breast cancer surgery were randomly assigned to either TPVB or LA followed by general anesthesia. An NRS value of >3 at rest or with movement 1 year following surgery defined PPP. Blinded interim analysis suggested rates of PPP much lower than anticipated, making detection of the specified 20 % absolute reduction in the primary outcome impossible. Recruitment was stopped, and all enrolled patients were followed to 1 year.

Results

A total of 145 participants were recruited; 65 were randomized to TPVB and 64 to LA. Groups were similar with respect to demographic and treatment characteristics. Only 9 patients (8 %; 95 % CI 4–14 %) met criteria for PPP 1 year following surgery; 5 were in the TPVB and 4 in the LA group. Brief Pain Inventory severity and interference scores were low in both groups. Arm morbidity and quality of life were similar in both groups. The 9 patients with PPP reported shoulder-arm morbidity and reduced quality of life.

Conclusions

This study reports a low incidence of chronic pain 1 year following major breast cancer surgery. Although PPP was uncommon at 1 year, it had a large impact on the affected patients’ arm morbidity and quality of life.     

Visualization of a looped and knotted epidural catheter with a guidewire

PURPOSE: To describe the management of a looped and knotted epidural catheter after analgesia for labour and delivery. CLINICAL FEATURES: Obstetrical epidural pain relief was provided for a 37-yr old woman in early labour. A 20-gauge Portex catheter was inserted at the L2-L3 interspace. Six centimetres of catheter was left in the epidural space. After vaginal delivery the catheter could not be removed. The catheter was left in situ for 24 hr. Repeated attempts at removal were again unsuccessful. The epidural catheter was not visible with fluoroscopy and it was impossible to inject radiopaque dye into the catheter. However, we successfully advanced a 0.016 inch guidewire through the epidural catheter and radiologically demonstrated a knot and part of a loop. The catheter was removed by an orthopedic surgeon using blunt dissection under local anesthetic from the soft tissue just lateral to the interspinous ligament. CONCLUSIONS: A knot can be a rare cause of a trapped epidural catheter. A suggested approach to the trapped lumbar epidural catheter: 1) Gentle traction on the catheter with the patient in various positions and in various degrees of lumbar flexion. 2) Test for catheter patency by injecting sterile, preservative-free, normal saline through the catheter. 3) Radiological imaging to determine if a knot is present and to determine its location, using radiopaque contrast for patent catheters or a guidewire for occluded catheters. 4) The approach to definitive management is based on the position of the knot. This can range from excision under local anesthetic to consultation with a surgical specialty for more invasive retrieval.     

Pilot study of an information aid for women with a family history of breast cancer

Objective

To develop and pilot study an information aid for women with a family history of breast cancer.

Design, setting and participants

The information aid, consisting of a booklet and audiotape, was developed by a multi-disciplinary team of health care professionals, breast cancer survivors and their relatives. Women with no personal history of breast cancer, on the waiting list for a familial breast cancer clinic at either of two centres, who could read English, were eligible for the pilot study which consisted of three sets of mailed questionnaires.

Main outcome measures

The baseline questionnaires included: demographic information: the Breast Cancer and Heredity Knowledge Scale (BCHK); psychological measures (the State-Trait Anxiety Inventory [STAI], Centre for Epidemiologic Studies Depression Scale [CES-D] and an item about breast cancer worry), and an item about breast cancer risk perception. Immediately after reviewing the information aid, participants completed a satisfaction survey, the risk perception and cancer worry items and a checklist about their personal family history. The third set of questionnaires, completed 2–4 weeks after reviewing the aid, was identical to the first. Patients then attended their scheduled clinic visit and an objective hereditary breast cancer risk assessment was made by the genetic counselling team.

Results and conclusions

Of 97 eligible women who were contacted, 67 completed all three sets of questionnaires. Overall, women were very satisfied with the aid and 96% would recommend it to other women. There was a highly significant improvement in their knowledge scores after they reviewed the aid. Anxiety and depression did not change and there was a decline in breast cancer worry. Risk perception did not change significantly. Ninety per cent of women completed their personal family history checklist accurately. Several important improvements have been made in the information aid and it will now be evaluated in the community.