The use of rotational thromboelastometry to guide management following Bitis nasicornis envenoming.

A man in his thirties presented following Bitis nasicornis envenoming. His coagulation was assessed using rotational thromboelastometry (ROTEM). It identified a subtle abnormality, not detected using standard laboratory assessments of coagulation, and influenced ongoing management. The abnormality resolved following treatment with antivenom. There are few documented cases of using ROTEM to assess patients following haemotoxic envenoming. This case highlights some of the potential benefits and limitations of doing so.

Undetected oesophageal perforation and feeding-tube misplacement.

This is a case report of an electromagnetically (EM)-guided Cortrak feeding tube that perforated the lower oesophagus and was not detected by the EM trace or by plain X-ray. Misplacement was diagnosed from computed tomography (CT) following injection of radio-contrast medium down the tube. Recommendations are offered for use of the EM trace in patients at high risk of oesophageal perforation.

Trauma hemostasis and oxygenation research position paper on remote damage control resuscitation: definitions, current practice, and knowledge gaps.

The Trauma Hemostasis and Oxygenation Research Network held its third annual Remote Damage Control Resuscitation Symposium in June 2013 in Bergen, Norway. The Trauma Hemostasis and Oxygenation Research Network is a multidisciplinary group of investigators with a common interest in improving outcomes and safety in patients with severe traumatic injury. The network's mission is to reduce the risk of morbidity and mortality from traumatic hemorrhagic shock, in the prehospital phase of resuscitation through research, education, and training. The concept of remote damage control resuscitation is in its infancy, and there is a significant amount of work that needs to be done to improve outcomes for patients with life-threatening bleeding secondary to injury. The prehospital phase of resuscitation is critical in these patients. If shock and coagulopathy can be rapidly identified and minimized before hospital admission, this will very likely reduce morbidity and mortality. This position statement begins to standardize the terms used, provides an acceptable range of therapeutic options, and identifies the major knowledge gaps in the field.

Implementation and execution of military forward resuscitation programs.

Through necessity, military medicine has been the driver of medical innovation throughout history. The battlefield presents challenges, such as the requirement to provide care while under threat, resource limitation, and prolonged evacuation times, which must be overcome to improve casualty survival. Focus must also be placed on identifying the causes, and timing, of death within the battlefield. By doing so, military medical doctrine can be shaped, appropriate goals set, new concepts adopted, and relevant technologies investigated and implemented. The majority of battlefield casualties still die in the prehospital environment, before reaching a medical treatment facility, and hemorrhage remains the leading cause of potentially survivable death. Many countries have adopted policies that push damage control resuscitation forward into the prehospital setting, while understanding the need for timely medical evacuation. Although these policies vary according to country, the majority share many common principles. These include the need for early catastrophic hemorrhage control at point-of-wounding, judicious use of fluid resuscitation, use of blood products as far forward as possible, and early evacuation to a surgical facility. Some countries place medical providers with the ability, and resources, for advanced resuscitation with the forward fighting units (perhaps at company level), whereas others have established en route resuscitation capabilities. If we are to continue to improve battlefield casualty survival, we must continue to work together and learn from each other. We must also carry on working alongside our civilian colleagues so that the benefits of translational experience are not lost. This review describes several countries current military approaches to prehospital trauma care. These approaches, refined through a decade of experience, merit consideration for integration into civilian prehospital care practice.

Challenges and possibilities in forward resuscitation.

The environmental and logistical constraints of the prehospital setting make it a challenging place for the treatment of trauma patients. This is perhaps more pronounced in the management of battlefield casualties before extraction to definitive care. In seeking solutions, interest has been renewed in implementing damage control resuscitation principles in the prehospital setting, a concept termed remote damage control resuscitation. These developments, while improving conflict survival rates, are not exclusive to the military environment, with similar situations existing in the civilian setting. By understanding the pathophysiology of shock, particularly the need for oxygen debt repayment, improvements in the assessment and management of trauma patients can be made. Technology gaps have previously hampered our ability to accurately monitor the prehospital trauma patient in real time. However, this is changing, with devices such as tissue hemoglobin oxygen saturation monitors and point-of-care lactate analysis currently being refined. Other monitoring modalities including newer signal analysis and artificial intelligence techniques are also in development. Advances in hemostatic resuscitation are being made as our understanding and ability to effectively monitor patients improve. The reevaluation of whole-blood use in the prehospital environment is yielding favorable results and challenging the negative dogma currently associated with its use. Management of trauma-related airway and respiratory compromise is evolving, with scope to improve on currently accepted practices. The purpose of this review is to highlight the challenges of treating patients in the prehospital setting and suggest potential solutions. In doing so, we hope to maintain the enthusiasm from people in the field and highlight areas for prehospital specific research and development, so that improved rates of casualty survival will continue.

Long-term event-free survival with an embolised prosthetic valve leaflet in the thoracic aorta.

We report the case of a patient who underwent a redo surgery for a leaflet escape from a Bjork-Shiley tilting disc mitral prosthesis inserted 18 years previously. The escaped disc remained lodged in the thoracic aorta without any complication. She ultimately died of terminal heart failure 13 years after the second operation. We believe this to be the longest survival with a dislodged leaflet from a mechanical valve. Removal of dislodged disc is recommended in literature but there may be a place for watchful observation in exceptional cases with no haemodynamic compromise.

Alteration in transthoracic impedance following cardiac surgery.

INTRODUCTION: Haemodynamically significant ventricular tachyarrhythmias are a frequent complication in the immediate post-operative period after cardiac surgery. Successful cardioversion depends on delivery of sufficient current, which in turn is dependent on transthoracic impedance (TTI). However, it is uncertain if there is a change in TTI immediately following cardiac surgery using cardiopulmonary bypass (CPB). METHODS: TTI was measured on 40 patients undergoing first time isolated cardiac surgery using CPB. TTI was recorded at 30 kHz using Bodystat Multiscan 5000 equipment before operation (with and without a positive end-expiratory pressure (PEEP) of 5 cm of H(2)O) and then at 1, 4 and 24 h after the operation. Data was analyzed to determine the relationship between pre- and post-operative variables and TTI values. RESULTS: Mean pre-operative TTI was 54.5+/-10.55 ohms without PEEP and 61.8+/-15.4 ohms on a PEEP of 5 cm of H(2)O. TTI dropped significantly (p<0.001) after the operation to 47.2+/-10.6 ohms at 1 h, 42.6+/-10.2 ohms at 4 h and 41.8+/-10.4 ohms at 24 h. A positive correlation was noted between duration of operation and TTI change at 1 h (r=0.38; p=0.016). There was no significant correlation between the duration of bypass and change in TTI. CONCLUSION: TTI decreases by more than 30% in the immediate post-operative period following cardiac surgery. This state may favour defibrillation at lower energy levels.

Cardiac compression following cardiac surgery due to unrecognised hiatus hernia.

A 76-year-old man who had undergone a routine coronary artery bypass grafting operation developed severe haemodynamic instability in the early postoperative period in spite of multiple inotropic supports. Due to persistent instability of haemodynamics and worsening acidosis his chest was re-explored with detection of no obvious abnormality. An intra-aortic balloon pump (IABP) was inserted for additional support. The chest had to be left open overnight and closed formally next morning. A chest X-ray at that stage showed a large hiatus hernia with huge gastric dilatation compressing the heart. Decompressions of the stomach lead to dramatic improvement in his circulatory status with rapid weaning of inotropes and IABP and he could be extubated. This case illustrates the importance of recognising the presence of hiatus hernia in preoperative chest X-ray and prophylactic NG tube insertion at the time of cardiac surgery in these cases.

Magnetic resonance imaging of the hip: detection of labral and chondral abnormalities using noncontrast imaging.

PURPOSE: Traditional imaging techniques have limited ability to detect subtle chondral and labral injuries of the hip. We performed a retrospective review of patients who underwent magnetic resonance imaging (MRI) of the hip and subsequent hip arthroscopy in order to evaluate the ability of optimized, noncontrast MRI to identify tears of the acetabular labrum and defects in articular cartilage. TYPE OF STUDY: Retrospective review of a consecutive sample. METHODS: Between January 1997 and July 2000, 92 patients had MRI of the hip, followed by arthroscopic surgery of that hip by 1 of 2 surgeons (R.B., D.E.P.). Two musculoskeletal MR radiologists blinded to the initial MRI and surgical findings, independently interpreted the studies, looking for the location and degree of articular cartilage and acetabular labral pathology. RESULTS: Of the 92 patients studied, each of 2 radiologists correctly identified 83 (94%) and 84 (95%) of the 88 labral tears present at surgery, respectively. There was 92% interobserver agreement on the MRI studies. For articular cartilage defects on the femoral head and acetabulum, there was good agreement (92% and 86% within 1 grade) between MRI and surgical grading and between the 2 MR readers (kappa of 0.8 for femoral head cartilage and 0.7 for acetabular cartilage). CONCLUSIONS: This study shows that noncontrast MRI of the hip, using an optimized protocol, can noninvasively identify labral and chondral pathology. Such information may facilitate deciding which patients warrant surgical intervention, thus preserving hip arthroscopy as a therapeutic tool. LEVEL OF EVIDENCE: Level II, Development of Diagnostic Criteria Study.

A short asymmetric synthesis of (+)-lyoniresinol dimethyl ether.

A short, efficient synthesis of the lignan (+)-lyoniresinol dimethyl ether is described. The synthesis is achieved by asymmetric photocyclization of an achiral dibenzylidenesuccinate to a chiral aryldihydronaphthalene. (-)-Ephedrine is used as a chiral auxiliary to bias the atropisomeric equilibrium in the dibenzylidenesuccinate prior to the photochemical reaction. The synthesis of the title compound was accomplished in five steps, and the final product was recrystallized to constant melting point and rotation.

Three-dimensional echocardiography is superior to multiplane transoesophageal echo in the assessment of regurgitant mitral valve morphology.

AIMS: Transoesophageal echocardiography (TOE) plays a vital role in the assessment of mitral valve morphology. However, the accuracy of TOE may be limited by inadequate recognition of all segments. We aimed to evaluate the role of three-dimensional (3D) echocardiography in this respect. METHODS AND RESULTS: Seventy-five patients were studied prior to mitral valve repair surgery. A scoring protocol was devised for recognition of the eight Carpentier segments (0=inadequate for analysis, 1=adequate, 2=good). Using surgical findings as the gold standard, TOE and 3D were compared for adequate recognition scores and accurate detection of functional morphology. Adequate recognition was more frequently obtained with 3D imaging (97% of segments by 3D c.f. 90% by TOE; p = 0.000). The major difference was seen at the commissures (adequate scores in 143/150 commissures by 3D c.f. 90/150 by TOE; p = 0.000). 3D matched more closely to surgical findings, achieving exact functional description in 92% of segments vs 79% segments with TOE (p = 0.000). This incremental value of 3D was seen in both commissures and the anterior leaflet but not in the posterior leaflet. CONCLUSIONS: In this study 3D was superior not only for complete recognition of the mitral valve but also for the accurate localisation and identification of pathology.

Dopamine therapy for patients at risk of renal dysfunction following cardiac surgery: science or fiction?

OBJECTIVES: We aimed to evaluate the renoprotective role of renal-dose dopamine on cardiac surgical patients at high risk of postoperative renal dysfunction. The latter included older patients or those with pre-existing renal disease, elevated preoperative serum creatinine (Cr), poor ventricular function, hypertension, diabetes mellitus and unstable angina requiring intravenous therapy. METHODS: Fifty patients undergoing cardiopulmonary bypass (CPB) who fulfilled the entry criteria were prospectively randomized into two groups: Group 1 received a 'renal-dose' (3 microg kg(-1) min(-1)) dopamine infusion starting at anaesthetic induction for 48 h whilst saline infusion acted as placebo in Group 2. The anaesthetic and CPB regimes were standardized. Urinary excretion of retinol binding protein (RBP) indexed to Cr, an accurate and sensitive marker of early renal tubular damage, was assessed daily for 6 days. Additional outcome measures included daily fluid balance, blood urea and serum Cr. Statistical comparisons were made using ANOVA and Mann-Whitney U-test. RESULTS: No significant difference was found between the groups in their age, gender, preoperative NYHA class, ejection fraction, baseline serum Cr and duration of CPB and aortic cross-clamping. Renal replacement therapy was not required in any instance. Both groups demonstrated a similar and significant rise in urinary RBP throughout the study period. Dopamine-treated patients achieved more negative average fluid balance than those on placebo (5 vs. 229 ml, P<0.05). CONCLUSIONS: Renal-dose dopamine therapy failed to offer additional renoprotection to patients considered at increased risk of renal dysfunction after CPB.

Avoiding ischemia in latissimus dorsi muscle grafts: electrical prestimulation versus vascular delay.

BACKGROUND: Surgical mobilization of the latissimus dorsi muscle produces regional ischemic damage that may compromise its function in clinical applications such as cardiomyoplasty. We compared the effectiveness of two procedures designed to maintain blood flow throughout the mobilized muscle. METHODS: Adult pigs were assigned to two experimental groups: an electrically prestimulated group (n = 10) and a vascular delay group (n = 10). In the prestimulated group the left latissimus dorsi muscle was activated in situ at 2 Hz for 24 h/d. In the vascular delay group, the intercostal perforating arteries to the left latissimus dorsi muscle were divided. Two weeks later, hyperemic blood flow was measured by means of fluorescent microspheres immediately before and after mobilizing the latissimus dorsi muscle and again after recovery for a further 2 days. RESULTS: In the prestimulated group, blood flow was not significantly depressed in any region of the muscle immediately after mobilization, and blood flow increased significantly in proximal (p = 0.01), middle (p = 0.02), and distal (p = 0.007) regions following recovery. In muscles subjected to vascular delay the proximal and middle regions showed no significant changes in blood flow after mobilization or recovery, but flow in the distal region was 50% lower after mobilization (p = 0.003), and it remained significantly depressed even after recovery (p = 0.008). CONCLUSIONS: Prestimulation was significantly more effective than vascular delay in preserving distal blood flow. Because it is also less invasive and initiates metabolic transformation before mobilization, this technique should allow cardiac assistance to be introduced at an earlier postoperative stage without compromising the viability of the grafted muscle.

Improved viability of latissimus dorsi muscle grafts after electrical prestimulation.

Surgical mobilization of the latissimus dorsi muscle (LDM) produces fiber degeneration, particularly in the distal part of the graft, that may compromise its function in clinical applications such as dynamic cardiomyoplasty. In five rats, the left LDM was stimulated continuously at 10 HZ. After 5 weeks, vessels perforating the chest wall were divided and the left LDM was mobilized as a pedicle graft based on the thoracodorsal artery. Twenty-four hours later, animals were killed and left and right LDMs were incubated with the vital stain nitroblue tetrazolium. Five control rats underwent a similar procedure without prestimulation. Mobilization of the LDM resulted in a loss of viability in the distal third of the muscle graft. This was reduced significantly by prestimulation (P = 0.006). Blood flow to the distal LDM graft is known to be augmented by electrical stimulation in situ before mobilization; the present results show that there is an associated enhancement of viability. The clinical implications of this finding are discussed.