Anaesthetic management during open and percutaneous irreversible electroporation

BACKGROUND

Irreversible electroporation (IRE) is a novel tumour ablation technique involving repetitive application of electrical energy around a tumour. The use of pulsed electrical gradients carries a risk of cardiac arrhythmias, severe muscle contractions, and seizures. We aimed to identify IRE-related risks and the appropriate precautions for anaesthetic management.

METHODS

All patients who were treated with IRE were prospectively included. Exclusion criteria were arrhythmias, congestive heart failure, active coronary artery disease, and epilepsy. All procedures were performed under general anaesthesia with complete muscle relaxation during ECG-synchronized pulsing. Adverse events, cardiovascular effects, blood samples, cerebral activity, and post-procedural pain were analysed.

RESULTS

Twenty-eight patients underwent 30 IRE sessions for tumours in the liver, pancreas, kidney, and lesser pelvis. No major adverse events occurred during IRE. Median systolic and diastolic blood pressure increased by 44 mm Hg (range -7 to 108 mm Hg) and 19 mm Hg (range 1-50 mm Hg), respectively. Two transient minor cardiac arrhythmias without haemodynamic consequences were observed. Muscle contractions were mild and IRE caused no reactive brain activity on a simplified EEG. Pain in the first 24 h after percutaneous IRE was generally mild, but higher pain scores were reported after pancreatic treatment (mean VAS score 3; range 0-9).

CONCLUSIONS

Side-effects during IRE on tumours in the liver, pancreas, kidney, and lesser pelvis seem mild and manageable when current recommendations for anaesthesia management, including deep muscle relaxation and ECG synchronized pulsing, are followed. Electrical pulses do not seem to cause reactive cerebral activity and evidence for pre-existing atrial fibrillation as an absolute contra-indication for IRE is questionable.

The clinical significance of BRAF and NRAS mutations in a clinic-based metastatic melanoma cohort

BACKGROUND

BRAF and NRAS mutations are frequently found in melanoma tumours, and recently developed BRAF-targeted therapies demonstrate significant clinical benefit.

OBJECTIVES

We sought to investigate the clinical significance of BRAF and NRAS mutations in a clinic-based metastatic melanoma cohort.

METHODS

In total, 237 tumours, mostly metastatic lesions, from 203 patients were screened for mutations in exon 15 of BRAF and exon 2 of NRAS using Sanger sequencing. BRAF and NRAS mutation status was analysed in relation to clinical and histopathological characteristics, and outcome.

RESULTS

Mutation in BRAF and NRAS was present in 43% (88% V600E, 10% V600K) and 30% (48% Q61K, 40% Q61R) of metastatic melanomas, respectively. We found consistent BRAF and NRAS mutation status in all but one of 27 patients with multiple metastases. BRAF mutation was associated with younger age at primary diagnosis (P = 0.02). Among patients with distant metastatic melanoma, patients with BRAF-mutant tumours without BRAF inhibitor treatment had inferior survival compared with patients with BRAF inhibitor treatment [hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.10-5.01, P = 0.03]. We also observed a trend towards better prognosis for patients with wild-type and NRAS-mutant tumours compared with BRAF V600E-mutant tumours (HR 0.64, 95% CI 0.39-1.04, P = 0.07; and HR 0.76, 95% CI 0.48-1.21, P = 0.25, respectively).

CONCLUSIONS

We were able to confirm the effect of BRAF inhibitor treatment in a single clinical institution. The results suggest further that BRAF mutation is a weak prognostic factor but a strong predictive factor and that BRAF-mutant melanoma might constitute one or more distinct subtypes of the disease with certain aetiology and clinical outcome.

Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort

BACKGROUND

Sunlight exposure and fair skin are major determinants of human vitamin D production, but they are also risk factors for cutaneous malignant melanoma (MM). There is epidemiological evidence that all-cause mortality is related to low vitamin D levels.

METHODS

We assessed the avoidance of sun exposure as a risk factor for all-cause mortality for 29 518 Swedish women in a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort. Women were recruited from 1990 to 1992 and were aged 25 to 64 years at the start of the study. We obtained detailed information at baseline on their sun exposure habits and potential confounders. Multivariable flexible parametric survival analysis was applied to the data.

RESULTS

There were 2545 deaths amongst the 29 518 women who responded to the initial questionnaire. We found that all-cause mortality was inversely related to sun exposure habits. The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group, resulting in excess mortality with a population attributable risk of 3%.

CONCLUSION

The results of this study provide observational evidence that avoiding sun exposure is a risk factor for all-cause mortality. Following sun exposure advice that is very restrictive in countries with low solar intensity might in fact be harmful to women's health.

Photosensitivity mechanism of undoped poly(methyl methacrylate) under UV radiation at 325 nm and its spatial resolution limit

In this Letter, we provide evidence suggesting that the main photosensitive mechanism of an undoped poly(methyl methacrylate)-based microstructured optical fiber under UV radiation at 325 nm is a competitive process of both photodegradation and polymerization. We found experimentally that increasing strain during photo-inscription leads to an increased photosensitivity, which is evidence of photodegradation. Likewise, refractive index change in the fiber was measured to be positive, which provides evidence for further polymerization of the material. Finally, we relate the data obtained to the spatial recording resolution of the samples.

Immunolocalization and expression of small-conductance calcium-activated potassium channels in human myometrium

Small-conductance calcium-activated potassium (SK3) channels have been detected in human myometrium and we have previously shown a functional role of SK channels in human myometrium in vitro. The aims of this study were to identify the precise localization of SK3 channels and to quantify SK3 mRNA expression in myometrium from pregnant and non-pregnant women. Myometrial biopsies were obtained from pregnant (n = 11) and non-pregnant (n = 11) women. The expression of SK3 channels was assessed using immunohistochemistry and SK3 mRNA was determined by qRT-PCR. In non-pregnant myometrium SK3 immunoreactivity was observed in CD34 positive (CD34(+)) interstitial Cajal-like cells (ICLC), now called telocytes. Although CD34(+) cells were also present in pregnant myometrium, they lacked SK3 immunoreactivity. Furthermore, the immunohistochemical results showed that SK3 expression in vascular endothelium was similar between the two groups. CD117 immunoreactivity was only detected in small round cells that resemble mast cells. Compared to non-pregnant myometrium we found significantly less SK3 mRNA in pregnant myometrium. We demonstrate that SK3 channels are localized solely in CD34(+) cells and not in smooth muscle cells, and that the molecular expression of SK3 channels is higher in non-pregnant compared to pregnant myometrium. On the basis of our previous study and the present findings, we propose that SK3 activators reduce contractility in human myometrium by modulating telocyte function. This is the first report to provide evidence for a possible role of SK3 channels in human uterine telocytes.

World Health Organization-defined classification of myeloproliferative neoplasms: morphological reproducibility and clinical correlations--the Danish experience

We examined inter- and intraobserver reproducibility and concordance between histological diagnosis and independently collected clinical findings in a large series of patients with the major subtypes of myeloproliferative neoplasms (MPNs) and controls. Seven hematopathologists reviewed 272 bone marrow biopsies including 43 controls. Diagnoses were determined according to the 2008 criteria of the World Health Organization (WHO). The participants were blinded to all clinical data except patient age. After initial evaluation all hematopathologists participated in a 3-day meeting with a leading clinician chaired by an expert hematopathologists. In cases with lack of consensus on fiber grading (n = 57), a new evaluation was performed. In cases with discordance on morphological diagnosis (n = 129), an additional nonblinded evaluation taking clinical data into consideration was carried out. For remaining cases with a lack of concordance between morphological diagnosis and clinical diagnosis (n = 33), a similar nonblinded evaluation was performed. Consensus on final histological diagnosis and concordance with clinical diagnosis were determined. Blinded histological evaluation resulted in a 53% consensus rate. After re-evaluation of fiber content, consensus was reached in 60% of cases. Adding clinical data increased the histological consensus to 83%. For cases with a histological consensus, we found a concordance of 71% with the clinician's diagnoses. This is the first study to present a larger cohort of MPN patients mimicking the diagnostic challenges that hematopathologists face in their daily practice. The results support the postulates of the WHO that both morphological and clinical findings are essential for a valid diagnosis

Comparison of the Dutch and English versions of the Carolinas Comfort Scale: a specific quality-of-life questionnaire for abdominal hernia repairs with mesh

PURPOSE

Repair of abdominal wall hernias with mesh is one of the most common procedures in general surgery. The introduction of hernia repair with mesh has lowered recurrence rates and shifted the focus to quality of life after surgery, raising the need for a specific tool measuring quality of life. The Carolinas Comfort Scale (CCS) is a questionnaire designed specifically for patients having hernia repair with mesh. The aim of this study is to validate the Dutch CCS and to compare it to the generic short form-36 (SF-36).

METHODS

The CCS questionnaire was translated into Dutch. Patients undergoing mesh hernia repair between April 2010 and December 2011 completed the CCS, the SF-36 and four questions comparing these two questionnaires in the first week after surgery. After 3 weeks, the CCS was repeated. Correlations between the two surveys were calculated using the Spearman's rank correlation test with a 95 % confidence interval to determine validity.

RESULTS

The response rate was 60.3 % (100/168). The CCS showed excellent reliability with a Cronbach's α of 0.948. Significant correlation existed between the CCS and the domains physical functioning, bodily pain, role-physical, vitality and social functioning of the SF-36. Seventy-nine percent of the patients preferred the CCS to the SF-36, and 83 % considered the CCS a better reflection of their quality of life after hernia repair with mesh.

CONCLUSION

The Dutch CCS appears a valid and clinically relevant tool for assessing quality of life after repair of abdominal wall hernia with mesh.

Highly photosensitive polymethyl methacrylate microstructured polymer optical fiber with doped core

In this Letter, we report the fabrication of a highly photosensitive, microstructured polymer optical fiber using benzyl dimethyl ketal as a dopant, as well as the inscription of a fiber Bragg grating in the fiber. A refractive index change in the core of at least 3.2×10(-4) has been achieved, providing a grating with a strong transmission rejection of -23 dB with an inscription time of only 13 min. The fabrication method has a big advantage compared to doping step index fiber since it enables doping of the fiber without using extra dopants to compensate for the index reduction in the core introduced by the photosensitive agent.

Bipolar radiofrequency ablation for symptomatic giant (>10 cm) hepatic cavernous haemangiomas: initial clinical experience

AIM

To describe initial clinical experience with bipolar radiofrequency ablation (RFA) for symptomatic giant hepatic haemangiomas.

MATERIALS AND METHODS

Four consecutive patients with a large-volume, symptomatic hepatic cavernous haemangioma of >10 cm were treated with bipolar RFA during laparotomy with ultrasound guidance. Complications were carefully noted. Clinical and radiological effectiveness were evaluated comparing baseline with 3 and 6 months follow-up of symptom assessments and upper abdominal magnetic resonance imaging (MRI) or computed tomography (CT).

RESULTS

RFA was successfully performed for all four giant haemangiomas. No major complications were observed. Peri-procedural shrinking was remarkable and intermediate-term volume reduction ranged from 58-92% after 6 months. Symptom relief after 6 months was complete in two patients and considerable in the other two.

CONCLUSION

Preliminary results suggest intra-operative bipolar RFA to be a safe, feasible, and effective technique for treatment of giant symptomatic hepatic cavernous haemangiomas.

Intraoperative transfusion threshold and tissue oxygenation: a randomised trial

BACKGROUND AND OBJECTIVES

Transfusion with allogeneic red blood cells (RBCs) may be needed to maintain oxygen delivery during major surgery, but the appropriate haemoglobin (Hb) concentration threshold has not been well established. We hypothesised that a higher level of Hb would be associated with improved subcutaneous oxygen tension during major spinal surgery.

MATERIALS AND METHODS

Fifty patients aged 18 years or older scheduled for spinal fusion with instrumentation were included and randomised to receive RBCs at either a Hb concentration of 7·3 g dL(-1) (restrictive group) or a Hb concentration of 8·9 g dL(-1) (liberal group) (Registration no.: H-C-2009-072). Oxygen tension was measured with a polarographic electrode placed subcutaneously over the left deltoid muscle. The primary endpoint was subcutaneous oxygen tension at the time most patients were still undergoing surgery.

RESULTS

Forty-eight patients were included in the intention-to-treat analysis; 25 patients in the restrictive group and 23 patients in the liberal group. The median change in subcutaneous oxygen tension 60 min after surgical incision was -0·79 and -0·75 kPa in the restrictive and the liberal groups, respectively (P = 0·78). No significant difference was found in the lowest subcutaneous oxygen tension; -2·07 vs. -1·95 kPa in the restrictive and the liberal groups, respectively (P = 0·85).

CONCLUSION

A Hb concentration transfusion threshold of 8·9 g dL(-1) was not associated with a higher subcutaneous oxygen tension during major spinal surgery than a threshold of 7·3 g dL(-1), but the trial was compromised by methodological difficulties.