Real time shear waves elastography monitoring of thermal ablation: in vivo evaluation in pig livers

Background

Thermal ablation is a widely used minimally invasive treatment modality for different cancers. However, lack of a real-time imaging system for accurate evaluation of the procedure is one of the reasons of local recurrences. Shear waves elastography (SWE) is a new ultrasound (US) imaging modality to quantify tissue stiffness. The aim of the study was to assess the feasibility and accuracy of US elastography for quantitative monitoring of thermal ablation and to determine the elasticity threshold predictive of coagulation necrosis.

Methods

A total of 29 in vivo thermal lesions were performed in pig livers with radiofrequency system. SWE and B-mode images were acquired simultaneously. Liver elasticity was quantified by using SWE data and expressed in kilopascal. After the procedure, pathologic analysis of treated tissues was compared with US images. The sensitivity and positive predictive value of the SWE maps of tissue elasticity were calculated and compared with the boundaries of the pale coagulation necrosis areas found at pathology.

Results

The liver mean elasticity values before and after thermal therapy were 6.4 ± 0.3 and 38.1 ± 2.5 kPa, respectively (P < 0.0001). For a threshold of 20 kPa, sensitivity (i.e., the rate of pixels correctly detected as necrosed tissue) was 0.8, and the positive predictive value (i.e., the rate of pixels in the elastographic map >20 kPa that actually developed coagulation necrosis) was 0.83.

Conclusions

Tissue areas with coagulation necrosis are significantly stiffer than the surrounding tissue. SWE permits the real-time detection of coagulation necrosis produced by radiofrequency and could potentially be used to monitor US-guided thermal ablation.     

Utility of a microwave surgical instrument in sealing lymphatic vessels

Background

This study assessed the ability of a novel microwave coagulation surgical instrument (MWCX) to seal lymphatic vessels when compared with LigaSure (Valleylab, Boulder, CO), the Harmonic Scalpel (HS; Ethicon Endo-Surgery, Cincinnati, OH), and electric cautery.

Methods

The burst pressure of pig inguinal lymphatic vessels was assessed after the sealing of vessels with each surgical instrument. The rate of lymphorrhea from pig mesenteric lymphatic vessels was also investigated using indocyanine green and visualized with the Photodynamic Eye system (Hamamatsu Hotoniks, Hamamatsu, Japan).

Results

Burst pressures were higher with MWCX (average, 300 mm Hg), LigaSure (average, 290 mm Hg), and HS (average, 253 mm Hg) when compared with electric cautery (average, 152.3 mm Hg; vs MWCX: P = .002, vs LigaSure: P = .002, vs HS: P = .004). The rate of lymphorrhea was significantly lower with LigaSure (13.3%), HS (18.8%), and MWCX (13.3%) when compared with electric cautery (77.3%; vs LigaSure: P < .001, vs HS: P < .001, vs MWCX: P < .001).

Conclusions

MWCX was equivalent to LigaSure and HS in terms of the ability to seal lymphatic vessels.     

Microwave coagulation therapy and drug injection to treat splenic injury

Background

The present study compares the efficacy of 915- and 2450-MHz contrast-enhanced ultrasound (CEUS)–guided percutaneous microwave coagulation with that of CEUS-guided thrombin injection for the treatment of trauma-induced spleen hemorrhage.

Materials and methods

In a canine splenic artery hemorrhage model with two levels of arterial diameter (A, <1 mm and B, between 1 and 2 mm), hemostatic therapy was performed using 915- and 2450-MHz microwaves and drug injection. Therapy efficacy was measured by comparing bleeding rate, hemostatic time, bleeding index, bleeding volume, and pathology.

Results

The most efficient technique was CEUS-guided 915-MHz percutaneous microwave coagulation therapy in terms of action time and total blood loss. The success rate of the 915-MHz microwave group was higher than that of the 2450-MHz microwave and the drug injection groups (except A level, P < 0.05). Hemostatic time, bleeding index, and bleeding volume were significantly less in the 915-MHz microwave group than those in the 2450-MHz microwave and drug injection groups (P < 0.05). Obvious degeneration and necrosis of parenchyma and large intravascular thrombosis were observed in the cavity of larger vessels in the 915-MHz microwave group, but pathologic changes of light injury could be seen in the other groups.

Conclusions

The present study provides evidence that microwave coagulation therapy is more efficient than thrombin injection for the treatment of splenic hemorrhage. Furthermore, treatment with 915-MHz microwaves stops bleeding more rapidly and generates a wider cauterization zone than does treatment with 2450-MHz microwaves.     

Tumour Necrosis Is an Indicator of Aggressive Biology in Patients with Urothelial Carcinoma of the Upper Urinary Tract

Background

Prognostic factors after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC) are inconclusive, because most data in the literature have been obtained from small series.

Objective

To assess the association of tumour necrosis with cancer recurrence and survival in a large international series of patients treated with RNU.

Design, setting, and participants

Data were collected from 1425 patients treated with RNU at 13 centres and combined into a relational database. Pathologic slides were re-reviewed by genitourinary pathologists according to strict criteria. Extensive tumour necrosis was scored as >10% of the tumour area.

Intervention

Patients underwent either open or laparoscopic RNU. Lymph node dissection was performed in the presence of enlarged nodes.

Measurements

Recurrence was defined as tumour relapse in the operative field, lymph node (LN) metastasis, and/or distant metastases. Bladder recurrences were not considered. Associations of extensive tumour necrosis with recurrence-free survival and cancer-specific survival were evaluated by univariate and multivariate analyses.

Results and limitations

Extensive tumour necrosis was observed in 364 patients (25.5%) and was associated with advanced tumour stage, high tumour grade, sessile architecture, lymphovascular invasion (LVI), concomitant carcinoma in situ, and LN metastasis (p < 0.0001 each). Extensive tumour necrosis was independently associated with disease recurrence and survival (p = 0.037 and p = 0.046, respectively) after adjusting for the effects of pathologic stage, grade, LVI, and LN status. The addition of extensive tumour necrosis to a base model comprising standard pathologic predictors marginally improved its predictive accuracy for both cancer-specific recurrence (1.5%) and survival (1.4%).

Conclusions

Extensive tumour necrosis is an independent predictor of clinical outcomes in patients who undergo RNU for UTUC. Assessment of tumour necrosis may help to identify patients who could benefit from multimodal therapy after RNU in the future. Evaluation of extensive tumour necrosis should be part of standard pathologic reporting.     

External Validation of the Mayo Clinic Stage,Size, Grade,and Necrosis (SSIGN) Score for Clear-Cell Renal Cell Carcinoma in a Single European Centre Applying Routine Pathology

Background

The stage, size, grade, and necrosis (SSIGN) score has been created as an outcome prediction tool for clear-cell renal cell carcinoma (ccRCC) using review pathology.

Objective

We evaluated the prognostic accuracy of the SSIGN score model using routine pathology records.

Design, setting, and participants

We retrospectively evaluated pathology records of 1862 consecutive ccRCC patients with complete data including follow-up who had been operated between 1984 and 2006.

Intervention

Surgical treatment of patients with ccRCC.

Measurements

TNM stage, largest tumour diameter, tumour grade, and presence of histologic tumour necrosis were recorded. ccRCC were categorised according to the SSIGN-score algorithm as 0–15. Cancer-specific survival (CSS) was assessed using the Kaplan-Meier method for individual SSIGN-score categories (scores 0–1 and ≥10, respectively, were combined). For evaluation of the prognostic impact of stage, size, grade, and necrosis regarding CSS, a multivariate analysis using a Cox regression model was performed, and for assessment of prognostic accuracy, Harrell's concordance index was performed.

Results and limitations

Median tumour diameter was 5.0 cm (range: 0.6–22 cm). Tumour necrosis was noted in 607 tumours (32.6%). Median follow-up was 72.5 mo (range: 0–281 mo); 359 of 1862 patients (19.3%) died of RCC. Ten-year CSS rates for respective SSIGN scores in our study ranged from 96.5% (scores 0–1) to 19.2% (scores ≥10). pT categories, lymph-node status, distant metastases, high tumour grade (size ≥5 cm), and necrosis were each independent predictors of CSS. The Harrell's concordance index was 0.823. Limitations included smaller sample sizes in higher risk categories and limited numbers of patients at risk after 10 yr.

Conclusions

Outcome prediction with the SSIGN score using routine pathology records was comparable to the original data based on review pathology. Combining scores into five categories improved discrimination. Our data support the routine use of the SSIGN score in clinical practice with regard to follow-up decisions and patient selection for adjuvant trials.     

D-dimer levels remain elevated in acute aortic dissection after 24 h

Background

D-dimer levels are elevated in patients with acute aortic dissection (AAD). Although D-dimer levels have been used to rule out AAD within 24 h of symptom onset, it is unknown whether they may be used reliably after 24 h but within the acute period. Here, we tested the hypothesis that D-dimer levels remain elevated in AAD patients for at least 10 d after dissection onset.

Materials and methods

D-dimer levels were measured in preoperative heparinized plasma samples from 100 patients with confirmed AAD for up to 10 d after onset of dissection. When possible, serial samples were obtained for ≥2 d. D-dimer levels were measured in fibrinogen equivalent units using a BCS XP automated coagulation analyzer, which is approved for citrated samples. Therefore, we first validated our samples by comparing D-dimer levels in heparinized and citrated plasma samples from 29 individuals, including patients with and without aortic disease and healthy donors.

Results

The correlation between heparinized and citrated plasma samples was 0.991 (P ≤ 0.001). At a threshold of 1.6 μg/mL, the overall sensitivity of the D-dimer assay in AAD patients up to 10 d after onset of dissection was 95.3%.

Conclusions

D-dimer levels remained elevated in AAD patients over a 10-d period after dissection onset and may be helpful in ruling out AAD in patients who seek treatment after the first 24 h but within the acute period. Heparinized plasma samples may be substituted for citrated samples when evaluating D-dimer levels using the BCS XP coagulation analyzer.     

A predictive model of early mortality in trauma patients

Background

Rapid thrombelastography (rTEG) is a real-time whole-blood viscoelastic coagulation assay. We hypothesized that admission rTEG and clinical data are independent predictors of trauma-related mortality.

Methods

Prospective observational data (patient demographics, admission vital signs, laboratory studies, and injury characteristics) from trauma patients enrolled within 6 hours of injury were collected. Mann–Whitney U test and analysis of variance test assessed significance (P ≤ .05). Logistic regression analyses determined the association of the studied variables with 24-hour mortality.

Results

Seven hundred ninety-five trauma patients were enrolled, of which 55 died within 24 hours of admission. Admission variables which independently predicted 24-hour mortality were as follows: Glasgow Coma Scale ≤8, hemoglobin <11 g/dL, international normalized ratio >1.5, Ly30 >8%, and penetrating injury (P < .05). This 5-variable model's area under the receiver operator characteristic curve was .88. The Hosmer–Lemeshow goodness-of-fit test was .90.

Conclusions

This 5-variable model provides a rapid prediction of 24-hour mortality. The inclusion of rTEG Ly30 demonstrates the association of fibrinolysis with outcome and may support the early use of antifibrinolytic therapies.     

Establishment of a Simple Living Donor Liver Transplantation Dog Model Using a Two-Step Nonvenous Bypass Hepatectomy

Aim

Dogs are an ideal model for studying living donor liver transplantation (LDLT). However, due to their poor tolerance to congestion and acidosis during portal vein blockage, current LDLT dog models with long operation times have high mortality. To address the issue, we designed a novel simplified operation with two-step nonvenous bypass (NVB) hepatectomy.

Methods

Eighty dogs were evenly randomized to the living liver donor (LLD) or the recipient (LLR) groups. A standard lobectomy of I, II, and III lobes was performed in the LLD group. In the LLR group, first only I, II, and III lobes were resected using NVB; the residual lobes were resected off just after donor lobes were implanted.

Results

For the LLD group, the operation time was 172.67 ± 20.98 minutes, amount of blood loss was 71.39 ± 13.59 mL, and 2-week survival rate was 85.00%. For the LLR group, the operation time was 251.61 ± 22.87 minutes, amount of blood loss was 220.00 ± 96.40 mL, amount of blood transfusion was 163.89 ± 44.74 mL, and 48-hour survival rate was 77.14%. In the LLR group, the mean arterial and central venous pressures decreased after organ implantion, but gradually recovered to normal levels after surgery. The liver function biochemical parameters recovered to preoperational levels after 14 days in the LLD group; in the LLR group, they gradually increased during 48 hours after operation.

Conclusion

The present method with two-step NVB hepatectomy can be used efficiently and safely for establishing LDLT dog model.     

Renal Allograft Outcome in Recipients of Positive-Crossmatch Combined Liver-Kidney Transplantation

Background

Successful kidney transplantation despite positive crossmatch (+CXM) before transplantation is well recognized in combined liver-kidney transplant (CLKT) recipients. This is probably due to immunologic protection of the renal allograft (RA) conferred by the liver allograft. However, occurrences of antibody-mediated rejection and poor long-term RA outcome is also documented with +CXM CLKT recipients, suggesting that such immunologic protection may not be universal.

Methods

A total of 1,401 CLKT recipients with known status of pre-transplantation CXM were identified from the United Network for Organ Sharing registry from January 1, 1986, to December 31, 2006. Univariate analysis for significant differences in clinical variables and Kaplan-Meier estimate for patient and graft survivals were performed. The results were compared between positive and negative CXM groups.

Results

Pre-transplantation +CXM was seen in 17.3% (242/1401) of CLKT recipients studied. The demographic and clinical characteristics were similar between the groups, except for higher panel reactive antibody level and CXM positivity in female recipients. Outcome analysis showed higher RA rejection (19.3% vs 10.8%; P = .026) and increased hospital length of stay (37.3 ± 46.0 vs 28.8 ± 33.2 days; P = .028) in the +CXM group. RA survivals at 1, 3, and 5 years were 8%, 7%, and 6% lower in the +CXM group. The patient and liver allograft survivals were not different between the groups.

Conclusions

In CLKT recipients with pre-transplantation +CXM, the immunologic protection of RA conferred by the liver allograft is less robust than previously perceived and may lead to higher rejection rate and poor RA outcome. This can be mitigated with routine pre-transplantation CXM.     

The neurokinin 1 receptor regulates peritoneal fibrinolytic activity and postoperative adhesion formation

Background

Intra-abdominal adhesions are a common source of postoperative morbidity. Previous studies in our laboratory have shown that a neurokinin 1 receptor antagonist (NK-1RA) reduces abdominal adhesion formation and increases peritoneal fibrinolytic activity. However, the cellular pathway by which the antagonist exerts its effects is unclear, as cultured peritoneal mesothelial cells exposed to the NK-1RA show increases in fibrinolytic activity despite having very low expression of neurokinin 1 receptor (NK-1R) messenger RNA and protein. Our aim was to determine whether the NK-1R plays an essential role in the adhesion-reducing effects of the NK-1RA, or if the NK-1RA is acting independently of the receptor.

Methods

Homozygous NK-1R knockout mice and age matched wild-type mice underwent laparotomy with cecal cautery to induce adhesions. At the time of surgery, mice received a single intraperitoneal dose of either NK-1RA (25 mg/kg) or saline alone. Adhesion severity at the site of cecal cautery was assessed on postoperative day 7. In a separate experiment, peritoneal fluid was collected from wild type and NK-1R knockout mice 24 h after laparotomy with cecal cautery and administration of either NK-1RA or saline. Tissue plasminogen activator levels, representative of total fibrinolytic activity, were then measured in peritoneal fluid.

Results

In wild-type mice, NK-1RA administration significantly decreased adhesion formation compared with saline controls. Among the NK-1R knockout mice, there was no significant reduction in adhesion formation by the NK-1RA. Fibrinolytic activity increased 244% in wild-type mice administered NK-1RA compared with saline controls; however, the NK-1RA did not raise fibrinolytic activity above saline controls in NK-1R knockout mice.

Conclusions

These data indicate that the NK-1R mediates the adhesion-reducing effects of the NK-1RA, in part, by the upregulation of peritoneal fibrinolysis, and suggest that the NK-1R is a promising therapeutic target for adhesion prevention.     

Combination of antithrombin and recombinant thrombomodulin attenuates leukocyte–endothelial interaction and suppresses the increase of intrinsic damage–associated molecular patterns in endotoxemic rats

Introduction

Both antithrombin (AT) and thrombomodulin are key players in physiological anticoagulant systems. Because the levels of both factors are known to decrease significantly during severe sepsis, we hypothesized that a combination therapy would be effective.

Methods

A sepsis model was established using the intravenous infusion of lipopolysaccharide (LPS). A dose of 125 IU/kg of AT, 0.25 mg/kg of recombinant thrombomodulin, or a combination of both agents was injected immediately after LPS infusion (n = 7, each). Intravital observation of the mesenteric microcirculation was performed, and leukocyte adhesion and blood flow were calculated at 3 h after LPS infusion. Immediately after the observation, blood samples were obtained and coagulation markers, organ damage markers, the circulating levels of nucleosome and high-mobility group box 1 were measured.

Results

Microscopic findings revealed the suppression of leukocyte adhesion and thrombus formation in the combination group. The number of adhesive leukocytes on the endothelium was significantly suppressed (P < 0.01), and the blood flow in venules was better maintained in the combination group compared with the placebo control (P < 0.01). The blood samples showed the suppressed activation in coagulation, no significant changes were observed in the organ damage markers in the treatment groups. The circulating levels of nucleosome and high-mobility group box 1 were both decreased significantly in the combination group compared with the placebo control (P < 0.01).

Conclusions

The coadministration of AT and recombinant thrombomodulin is effective for the suppression of leukocyte activation and cell death during sepsis.     

Bacterial translocation induces proinflammatory responses and is associated with early death in experimental severe injury

Objective

An experimental model of severe injury with great lethality was studied to define the impact of bacterial translocation on survival and on inflammatory response.

Methods

Forty-one rabbits were divided into two groups: A, femur myotomy; and B, myotomy and fracture of the femoral bone. Vital signs and survival were recorded. Serum circulating endotoxins (lipopolysaccharides; LPS) were determined and tissue cultures were performed at necropsy. A subgroup of animals was sacrificed at 48 h post injury; LPS was determined in abdominal aorta and portal vein, apoptosis of spleen cells was assessed by flow cytometry, and ex vivo production of tumor necrosis factor alpha by splenocytes was measured.

Results

Tissue bacterial burden was increased in animals that died early (i.e., within 48 h after injury) versus rabbits that died later. Portal vein LPS at 48 h was increased in group B compared with group A, whereas circulating LPS did not differ. No difference in apoptosis of either lymphocytes or macrophages of the spleen was found in group B compared with group A. Following stimulation with LPS or phytohemagglutinin, tumor necrosis factor α production by splenocytes of group B was greater than that of group A.

Conclusions

Bacterial translocation primes enhanced proinflammatory responses and it is associated with early death in severe trauma.     

Healing of two microarterial anastomoses with diameter mismatch

Background

The use of fascial perforating vessels as recipients for microvascular composite tissue autotransplants has led to vessel diameter discrepancy becoming an increasingly common finding. Little evidence, however, is available to direct the choice of anastomotic technique where a discrepancy exists. We have been studying two methods of anastomosing arteries where a small-to-large discrepancy exists—a 45° section of the smaller vessel, and invaginating the smaller vessel inside the larger. As part of this work, this study examines intimal hyperplasia and healing of the two methods.

Materials and methods

A previously described paired Wistar rat femoral axis model was used. Anastomoses were performed, one on each side, and specimens were harvested in groups at 24 h, 1 wk, 6 wk, and 8 mo. Inflammation, necrosis, and fibrosis in each layer of the vessel wall and intimal hyperplasia were each scored by an assessor blinded to the group and anastomotic technique.

Results

Significant differences in healing were found. The invagination technique induced less inflammation, and caused less endothelial and medial necrosis than the oblique cut end-to-end method. Intimal hyperplasia was most pronounced at 6 wk, but no evidence of a difference in the severity of intimal hyperplasia between the two methods was found.

Conclusions

The invaginating anastomosis causes less inflammation and less vessel wall necrosis than the oblique end-to-end method in this model. This finding, alongside results from previous work, suggests that this is the better method to deal with a small-to-large microarterial diameter discrepancy in the range 1:1.5 to 1:2.5.     

Impact of Graft Infection on Long-Term Survival After Kidney Transplant

Background

Patients undergoing transplantation procedures are at a high risk of developing infections because of the need for immunosuppression. Infections presenting directly after renal transplantation greatly influence the overall success of the procedure. The aim of this study was to evaluate the influence of postoperative infection on the length of survival after renal transplant.

Methods

In 2009 a multicenter prospective trial evaluating the factors that influence the occurrence of postoperative infective complications was published by the authors. That study reported that 25 out of 232 recipients of a renal transplant were diagnosed with an infection. The present study shows the effect of postoperative infection on the length of survival after renal transplantation during a 15-year observation period. Statistical methods involved monofactorial and multifactorial Kaplan-Meier analysis for the length of survival and the Cox proportional hazards model for mortality prediction. A P value of <.05 was considered to indicate statistical significance.

Results

The analysis demonstrated that the lifespan of renal transplant recipients was decreased in those with postoperative infection, at both year 10 of the observation period (P = .013) and 15 years after transplantation (P = .012). Moreover, it was ascertained that an infection in the postoperative period was an independent risk factor increasing the mortality after renal transplantation: P = .026; hazard ratio 2.90 (95% confidence interval, 1.13–7.41).

Conclusions

The occurrence of an infection in the postoperative period significantly decreases the lifespan of a renal transplantation recipient.     

Late Biliary Obstruction in Wistar Rats After Intermittent Hepatic Pedicle Clamping

Introduction

The temporary vascular occlusion of hepatic flow is one of the essential procedures in hepatic surgery.

Aim

Evaluate the late liver alterations after intermittent pedicle hepatic clamping (IHPC) in Wistar rats.

Methods

Male Wistar rats (n = 14) with average weight of 281.1 g, were anesthetized with intraperitoneal ketamine 5%. The IHPC group (n = 7) was submitted to U-shaped abdominal incision; the hepatic pedicle was isolated and submitted to IHPC ischemia 4 times, 5 minutes each, followed by reperfusion 4 times, 5 minutes each. The simulated operation group (n = 7) was subjected to anesthesia, laparotomy, and manipulation of the hepatic pedicle. On day 35, after fasting for 12 hours, liver biopsies were collected and blood was tested for liver aminotransferases (aspartate aminotransferase/alanine aminotransferase).

Results

All the IHPC group animals had a dilated common bile duct and increased liver enzymes (P < .05 by Mann-Whitney test). Ductular proliferation (100% of cases), porta-porta septa (42.8%), formation of lumps (42.8%), foci of necrosis (14.2%), and bile plugs (14, 2%) were observed only in the IHPC group.

Conclusion

In rats, IHPC caused morphologic features leading to biliary obstruction.     

Augmented Reality: A New Tool To Improve Surgical Accuracy during Laparoscopic Partial Nephrectomy? Preliminary In Vitro and In Vivo Results

Background

Use of an augmented reality (AR)–based soft tissue navigation system in urologic laparoscopic surgery is an evolving technique.

Objective

To evaluate a novel soft tissue navigation system developed to enhance the surgeon's perception and to provide decision-making guidance directly before initiation of kidney resection for laparoscopic partial nephrectomy (LPN).

Design, setting, and participants

Custom-designed navigation aids, a mobile C-arm capable of cone-beam imaging, and a standard personal computer were used. The feasibility and reproducibility of inside-out tracking principles were evaluated in a porcine model with an artificially created intraparenchymal tumor in vitro. The same algorithm was then incorporated into clinical practice during LPN.

Interventions

Evaluation of a fully automated inside-out tracking system was repeated in exactly the same way for 10 different porcine renal units. Additionally, 10 patients underwent retroperitoneal LPNs under manual AR guidance by one surgeon.

Measurements

The navigation errors and image-acquisition times were determined in vitro. The mean operative time, time to locate the tumor, and positive surgical margin were assessed in vivo.

Results and limitations

The system was able to navigate and superpose the virtually created images and real-time images with an error margin of only 0.5 mm, and fully automated initial image acquisition took 40 ms. The mean operative time was 165 min (range: 135–195 min), and mean time to locate the tumor was 20 min (range: 13–27 min). None of the cases required conversion to open surgery. Definitive histology revealed tumor-free margins in all 10 cases.

Conclusions

This novel AR tracking system proved to be functional with a reasonable margin of error and image-to-image registration time. Mounting the pre- or intraoperative imaging properties on real-time videoendoscopic images in a real-time manner will simplify and increase the precision of laparoscopic procedures.     

Electromagnetic interference caused by common surgical energy-based devices on an implanted cardiac defibrillator

Background

Surgical energy-based devices emit energy, which can interfere with other electronic devices (eg, implanted cardiac pacemakers and/or defibrillators). The purpose of this study was to quantify the amount of unintentional energy (electromagnetic interference [EMI]) transferred to an implanted cardiac defibrillator by common surgical energy-based devices.

Methods

A transvenous cardiac defibrillator was implanted in an anesthetized pig. The primary outcome measure was the average maximum EMI occurring on the implanted cardiac device during activations of multiple different surgical energy-based devices.

Results

The EMI transferred to the implanted cardiac device is as follows: traditional bipolar 30 W .01 ± .004 mV, advanced bipolar .004 ± .003 mV, ultrasonic shears .01 ± .004 mV, monopolar Bovie 30 W coagulation .50 ± .20 mV, monopolar Bovie 30 W blend .92 ± .63 mV, monopolar instrument without dispersive electrode .21 ± .07 mV, plasma energy 3.48 ± .78 mV, and argon beam coagulator 2.58 ± .34 mV.

Conclusion

Surgeons can minimize EMI on implanted cardiac defibrillators by preferentially utilizing bipolar and ultrasonic devices.     

Palliative and end-of-life care training during the surgical clerkship

Background

In 2000, the Liaison Committee on Medical Education required that all medical schools provide experiential training in end-of-life care. To adhere to this mandate and advance the professional development of medical students, experiential training in communication skills at the end-of-life was introduced into the third-year surgical clerkship curriculum at Wright State University Boonshoft School of Medicine.

Materials and methods

In the 2007–08 academic year, 97 third-year medical students completed six standardized end-of-life care patient scenarios commonly encountered during the third-year surgical clerkship. Goals and objectives were outlined for each scenario, and attending surgeons graded student performances and provided formative feedback.

Results

All 97 students, 57.7% female and average age 25.6 ± 2.04 y, had passing scores on the scenarios: (1) Adult Hospice, (2) Pediatric Hospice, (3) Do Not Resuscitate, (4) Dyspnea Management/Informed Consent, (5) Treatment Goals and Prognosis, and (6) Family Conference. Scenario scores did not differ by gender or age, but students completing the clerkship in the first half of the year scored higher on total score for the six scenarios (92.8% ± 4.8% versus 90.5% ± 5.0%, P = 0.024).

Conclusions

Early training in end-of-life communication is feasible during the surgical clerkship in the third-year of medical school. Of all the scenarios, “Conducting a Family Conference” proved to be the most challenging.     

Effet du mouvement de balancement sur la douleur du travail avant la mise en place du cathéter péridural en position assise

Objectives

To assess the effects of rocking motion on labour pain and before epidural catheter insertion.

Study design

Clinical prospective observational study.

Patients and methods

Pain scores (numerical scale: 0–10) were recorded in 50 laboring women in three consecutive positions: lying down, sitting and then rocking back and forth while seated. The overall satisfaction (0–10) and any comment related to the rocking procedure were also recorded.

Results

One woman refused to rock during the procedure and five alternated moving and still periods. Pain scores were similar in the lying (8.1 ± 1.8) and sitting position (8.0 ± 1.8), whereas they significantly decreased while rocking (6.6 ± 1.7; p < 0.001 versus both lying and sitting still positions). Satisfaction associated with rocking chair motion was high (8.9 ± 1.4).

Discussion

Within the limits of an observational and preliminary study, we observed that rocking motion during the procedure was associated with a significant decrease in labour pain and that patient satisfaction was high. Several hypotheses are proposed to explain these effects, i.e. patient's involvement in an action that focuses attention, loss of parturient's landmarks and stimulation of the vestibular system which might lead to a change in the cognitive perception of the body.