Electrocardiographic changes during continuous intravenous application of bupivacaine in neonatal pigs

Background It is controversial as to whether T-wave elevation is caused by local anaesthetics, epinephrine, or their combination. It has been shown that T-elevation after intravascular injection of a small bupivacaine test dose is caused by epinephrine and not by bupivacaine. The aim of this study was to investigate ECG changes with higher doses of i.v. bupivacaine. Methods Thirty neonatal pigs were anaesthetized with sevoflurane and their tracheas intubated and artificially ventilated. Under steady-state conditions, bupivacaine was continuously infused (flow rate 3.2 ml kg−1 min−1) by a syringe infusion pump through a central venous catheter. Group 1 received bupivacaine 0.125%, Group 2 bupivacaine 0.5%. The ECG was continuously printed and subsequently analysed for alterations in heart rate, ventricular de- and repolarization, and arrhythmias at 1.25, 2.5, and 5 mg kg−1 bupivacaine infused. Results Sinus rhythm persisted in all pigs. Heart rate decreased progressively in both groups, but this was significantly more pronounced in Group 1. T-wave elevation occurred in 40% and 0% (Groups 1 and 2) at 1.25 mg kg−1, in 80% and 0% at 2.5 mg kg−1, and in 93% and 80% at 5 mg kg−1 bupivacaine infused. There were significant differences between the two groups at 1.25 and 2.5 mg kg−1 infused. Conclusions Higher doses of i.v. infused bupivacaine can cause T-elevation. With slower injection technique, T-elevation can already be detected at lower bupivacaine doses administere

Electrocardiographic alterations during intravascular application of three different test doses of bupivacaine and epinephrine: experimental study in neonatal pigs

Background Origin of electrocardiographic (ECG) alterations during intravascular injection of local anaesthetic solutions is controversial. The aim of this study was to elucidate whether epinephrine, bupivacaine or their combination is responsible for ECG alteration. Methods Forty-five piglets were randomized into three groups. After induction of general anaesthesia using sevoflurane and peripheral venous cannulation, the trachea was intubated, the lungs were artificially ventilated, and anaesthesia was maintained by sevoflurane. Under steady state 0.2 ml kg−1 and after 10 min 0.4 ml kg−1 of one of the following three test solutions was administered i.v.: bupivacaine 0.125% (Group 1), bupivacaine 0.125%+epinephrine 1:200 000 (Group 2), and plain epinephrine 1:200 000 (Group 3). The ECG was analysed for alterations in heart rate and T-elevation. Results After injection of 0.2 or 0.4 ml kg−1 test solution, an increase in heart rate of at least 10% was found in none of Group 1 and in all of Groups 2 and 3. After application of 0.2 ml kg−1 test solution, T-elevation was found in 7% of Group 1 and in 93% of Groups 2 and 3. The injection of 0.4 ml kg−1 revealed a T-elevation in 27%, 100%, and 100%, respectively, in Groups 1, 2, and 3. Conclusions This animal model demonstrated that increases in heart rate and T-elevation in the ECG during i.v. application of a common test dose (0.2 ml kg−1) of bupivacaine are caused by epinephrine addition. Whether higher doses of bupivacaine alone can cause similar ECG changes or not requires further studie

Causal effects of body mass index on airflow obstruction and forced mid-expiratory flow: a mendelian randomization study taking interactions and age-specific instruments into consideration toward a life course perspective

Obesity has complex links to respiratory health. Mendelian randomization (MR) enables assessment of causality of body mass index (BMI) effects on airflow obstruction and mid-expiratory flow. In the adult SAPALDIA cohort, recruiting 9,651 population-representative samples aged 18–60 years at baseline (female 51%), BMI and the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) as well as forced mid-expiratory flow (FEF25–75%) were measured three times over 20 follow-up years. The causal effects of BMI in childhood and adulthood on FEV1/FVC and FEF25–75% were assessed in predictive (BMI averaged over 1st and 2nd, lung function (LF) averaged over 2nd and 3rd follow-up; N = 2,850) and long-term cross-sectional models (BMI and LF averaged over all follow-ups; N = 2,728) by Mendelian Randomization analyses with the use of weighted BMI allele score as an instrument variable and two-stage least squares (2SLS) method. Three different BMI allele scores were applied to specifically capture the part of BMI in adulthood that likely reflects tracking of genetically determined BMI in childhood. The main causal effects were derived from models containing BMI (instrumented by BMI genetic score), age, sex, height, and packyears smoked as covariates. BMI interactions were instrumented by the product of the instrument (BMI genetic score) and the relevant concomitant variable. Causal effects of BMI on FEV1/FVC and FEF25–75% were observed in both the predictive and long-term cross-sectional models. The causal BMI- LF effects were negative and attenuated with increasing age, and stronger if instrumented by gene scores associated with childhood BMI. This non-standard MR approach interrogating causal effects of multiplicative interaction suggests that the genetically rooted part of BMI patterns in childhood may be of particular relevance for the level of small airway function and airflow obstruction later in life. The methodological relevance of the results is first to point to the importance of a life course perspective in studies on the etiological role of BMI in respiratory health, and second to point out novel methodological aspects to be considered in future MR studies on the causal effects of obesity related phenotypes

Benefits of specialisation in the management of pancreatic cancer:results of a Scottish population-based study

Pancreatic cancer is associated with a very poor prognosis; however, in selected patients, resection may improve survival. Several recent reports have demonstrated that concentration of treatment activity for patients with pancreatic cancer has resulted in improved outcomes. The aim of this study was to ascertain if there was any evidence of benefit for specialised care of patients with pancreatic cancer in Scotland. Records of patients diagnosed with pancreatic cancer during the period 1993-1997 were identified. Three indicators of co-morbidity were calculated for each patient. Operative procedures were classified as resection, other surgery or biliary stent. Prior to analysis, consultants were assigned as specialist pancreatic surgeons, clinicians with an interest in pancreatic disease or nonspecialists. Data were analysed with regard to 30-day mortality and survival outcome. The final study population included 2794 patients. The 30-day mortality following resection was 8%, and hospital or consultant volume did not affect postoperative mortality. The 30-day mortality rate following palliative surgical operations was 20%, and consultants with higher case loads or with a specialist pancreatic practice had significantly fewer postoperative deaths (P=0.014 and 0.002, respectively). For patients undergoing potentially curative or palliative surgery, the adjusted hazard of death was higher in patients with advanced years, increased co-morbidity, metastatic disease, and was lower for those managed by a specialist (RHR 0.63, 95% CI 0.50-0.78) or by a clinician with an interest in pancreatic disease (RHR 0.63, 0.48-0.82). The risk of death 3 years after diagnosis of pancreatic cancer is higher among patients undergoing surgical intervention by nonspecialists. Specialisation and concentration of cancer care has major implications for the delivery of health services

Point-to-point registration with mandibulo-maxillary splint in open and closed jaw position. Evaluation of registration accuracy for computer-aided surgery of the mandible

INTRODUCTION: Computer navigation plays an increasingly important role in craniomaxillofacial surgery. The difficulties in computer navigation at the craniomaxillofacial site lie in the accurate transmission of the dataset to the operating room. This study investigates the accuracy of the dental-splint registration method for the skull, midface, and mandible. MATERIAL AND METHODS: A synthetic human skull model was prepared with landmarks and scanned with cone beam computer tomography (CBCT). Two registration splints fixed the mandible against the viscerocranium in two different positions (closed vs. open). The target registration error was computed in all 278 landmarks spread over the entire skull and mandible in 10 repeated measurements using the VectorVision(2) (BrainLAB Inc., Feldkirchen, Germany) navigation system. RESULTS: If registered in the closed position an average precision of 2.07mm with a standard deviation (SD) of 0.78mm was computed for all landmarks distributed over the whole skull. Registration in the open position resulted in an average precision of 1.53mm (SD=0.55mm). For single landmarks the precision decreases linearly with distance from the reference markers. The longer the three-dimensional distance between the registration points, the more precise the computer navigation is, mainly in the most posterior area of the cranium. CONCLUSION: Our findings in the cranium are comparable with those of other studies. Artificial fixation of the lower jaw via splint seems to introduce no additional error. The registration points should be as far apart from each other as possible during navigation with the splint