Intracanal pressure in compressive spinal cord injury: reduction with hypothermia

Most cases of human spinal cord injury (SCI) are accompanied by continuing cord compression. Experimentally, compression results in rapid neurological decline over hours, suggesting a rise in intracanal pressure local to the site of injury. The aim of this study was to measure the rise in local intracanal pressure accompanying progressive canal occlusion and to determine the relationship between raised intracanal pressure and neurological outcome. We also aimed to establish whether hypothermia was able to reduce raised intracanal pressure. We demonstrate that, following SCI in F344 rats, local intracanal pressure remains near normal until canal occlusion exceeds 30% of diameter, whereupon a rapid increase in pressure occurs. Intracanal pressure appears to be an important determinant of neurological recovery, with poor long-term behavioural and histological outcomes in animals subject to 8?h of 45% canal occlusion, in which intracanal pressure is significantly elevated. In contrast, good neurological recovery occurs in animals with near normal intracanal pressure (animals undergoing 8?h of 30% canal occlusion or those undergoing immediate decompression). We further demonstrate that hypothermia is an effective therapy to control raised intracanal pressure, rapidly reducing elevated intracanal pressure accompanying critical (45%) canal occlusion to near normal. Overall these data indicate that following SCI only limited canal narrowing is tolerated before local intracanal pressure rapidly rises, inducing a sharp decline in neurological outcome. Raised intracanal pressure can be controlled with hypothermia, which may be a useful therapy to emergently decompress the spinal cord prior to surgical decompression.     

Comparison of coronary calcium and stress myocardial perfusion imaging in apparently healthy siblings of individuals with premature coronary artery disease

Detection of subclinical coronary atherosclerosis is possible using exercise myocardial perfusion imaging for inducible ischemia or multidetector computed tomography for coronary artery calcium (CAC), which is used to detect subclinical coronary atherosclerosis. The extent to which these screening tests converge in an asymptomatic population that is at increased risk for coronary artery disease remains unknown. We compared the concordance of findings in 260 asymptomatic middle-age siblings of hospitalized index patients <60 years of age with documented coronary artery disease. All subjects underwent maximal exercise testing with postexercise and delayed attenuation-corrected thallium single-photon emission computed tomography and multidetector computed tomography for CAC. An abnormal exercise single-photon emission computed tomographic (SPECT) result occurred in >50% of subjects with a CAC score >100, but also in 12% with no CAC, 9% with CAC scores of 1 to 10, and 20% with CAC scores of 11 to 100. In subjects with an abnormal exercise SPECT result, 59% had CAC scores < or =100. Overall, there was only a modest agreement between an abnormal exercise SPECT result and high CAC scores. In conclusion, although moderate or severe CAC is often associated with inducible ischemia, the absence of CAC or the presence of only mild CAC by no means precludes inducible myocardial ischemia. These screening tests may reflect different aspects or stages of coronary disease in an asymptomatic middle-age population.     

Measurement of the Lateral Ventricles in the Neonatal Head: Comparison of 2-D and 3-D Techniques

Neonatal cranial ultrasound is routinely performed to screen preterm infants for complications of prematurity. A key component of this examination is the measurement of the lateral ventricles to identify and monitor ventriculomegaly. This study assesses the two-dimensional (2-D) interobserver error of neonatal cranial lateral ventricle measurements on 40 neonates who were undergoing cranial ultrasound in the neonatal intensive care unit. Three-dimensional (3-D) volumes were obtained using a matrix transducer. Lateral ventricle (LV) measurements were subsequently measured on a departmental 3-D workstation by two workstation sonographers. The interobserver error of this technique was calculated and compared with the conventional 2-D technique. Both techniques demonstrated acceptable interobserver variability although the established 2-D technique had less variation. This identifies a potential role for 3-D analysis in the neonatal cranial ultrasound examination. It also affirms the potential of 3-D ultrasound in performing similar small measurements in other clinical settings.     

Evidence summaries tailored to health policy-makers in low- and middle-income countries

Objective

To describe how the SUPPORT collaboration developed a short summary format for presenting the results of systematic reviews to policy-makers in low- and middle-income countries (LMICs).

Methods

We carried out 21 user tests in six countries to explore users’ experiences with the summary format. We modified the summaries based on the results and checked our conclusions through 13 follow-up interviews. To solve the problems uncovered by the user testing, we also obtained advisory group feedback and conducted working group workshops.

Findings

Policy-makers liked a graded entry format (i.e. short summary with key messages up front). They particularly valued the section on the relevance of the summaries for LMICs, which compensated for the lack of locally-relevant detail in the original review. Some struggled to understand the text and numbers. Three issues made redesigning the summaries particularly challenging: (i) participants had a poor understanding of what a systematic review was; (ii) they expected information not found in the systematic reviews and (iii) they wanted shorter, clearer summaries. Solutions included adding information to help understand the nature of a systematic review, adding more references and making the content clearer and the document quicker to scan.

Conclusion

Presenting evidence from systematic reviews to policy-makers in LMICs in the form of short summaries can render the information easier to assimilate and more useful, but summaries must be clear and easy to read or scan quickly. They should also explain the nature of the information provided by systematic reviews and its relevance for policy decisions.     

Canadian Cardiovascular Society/Canadian Heart Rhythm Society Joint Position Statement on the Cardiovascular Screening of Competitive Athletes

Sudden cardiac death (SCD), especially in a young seemingly healthy individual, is a tragic and highly publicized event, which is often followed by a strong emotional reaction from the public and medical community.” Although rare, SCD in the young is devastating to families and communities, underpinning our society’s desire to avoid any circumstances predisposing to the loss of human life during exertion. The Canadian Cardiovascular Society Position Statement on the cardiovascular screening of athletes provides evidence-based recommendations for Canadian sporting organizations and institutions with a focus on the role of routine electrocardiogram (ECG) screening in preventing SCD. We recommend that the cardiac screening and care of athletes within the Canadian health care model comprise a sequential (tiered) approach to the identification of cardiac risk, emphasizing the limitations of screening, the importance of shared decision-making when cardiac conditions are diagnosed, and the creation of policies and procedures for the management of emergencies in sport settings. Thus, we recommend against the routine (first-line or blanket mass performance of ECG) performance of a 12-lead ECG for the initial cardiovascular screening of competitive athletes. Organization/athlete-centred cardiovascular screening and care of athletes program is recommended. Such screening should occur in the context of a consistent, systematic approach to cardiovascular screening and care that provides: assessment, appropriate investigations, interpretation, management, counselling, and follow-up. The recommendations presented comprise a tiered framework that allows institutions some choice as to program creation.