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Edited by Jonathan Wyatt; this scan coordinated by Mohammed Saeed
Unfractionated heparin and low molecular weight heparin in acute coronary syndrome without ST elevation: a meta analysis
Overview—Acute coronary syndrome without ST elevation is attributed to unstable angina and non-Q-wave myocardial infarction. The role of unfractionated and low molecular weight heparin (LMWH) in the management of aspirin treated patients with acute coronary syndrome without ST elevation has not been determined satisfactorily by any single large study. This meta-analysis investigates this issue.
Design—Meta-analysis of 12 randomised trials, involving a total of 17 157 patients.
Main outcome measures—The primary efficacy outcome measures were death and non-fatal myocardial infarction. The primary safety outcome measure was the occurrence of a major bleed. Secondary outcome measures of interest were recurrent angina and the need for re-vascularisation.
Main results—In aspirin treated patients, short-term (up to seven days) treatment with unfractionated heparin or LMWH was associated with significant reductions in death and non-fatal myocardial infarction (summary odds ratio 0.53; 95% CI 0.38, 0.73, p=0.0001), equivalent to 29 events prevented per 1000 patients. No significant difference was found between unfractionated heparin and LMWH during short-term treatment. Long term LMWH conferred no reduction in deaths or non-fatal infarcts, but was associated with a significantly increased risk of major bleeding (odds ratio 2.26, (95% CI 1.63, 3.14), p<0.0001), equivalent to 12 major bleeds per 1000 patients treated.
Conclusion—The authors conclude that there are benefits of using unfractionated heparin or LMWH in aspirin treated patients presenting with acute coronary syndrome without ST elevation in the short-term, but cannot find evidence to support its use beyond the first seven days.
Critique—Acute coronary syndrome without ST elevation (unstable angina and non-Q wave myocardial infarction) is a common presentation to accident and emergency. Patients who present in this way are at significant risk of developing recurrent ischaemic events. Previous randomised trials, while sizeable, have been of insufficient power to determine with certainty the role for the use of heparin products in addition to aspirin in these patients. This meta-analysis circumvents many of the shortfalls encountered in individual randomised trials. The combination of using data from more than 17 000 patients with clear, objective endpoints enabled the authors to reach conclusions that should help to shape future patient management. No differences were observed between unfractionated heparin and LMWH in either efficacy (death or myocardial infarction) or safety (major bleeds), based on a meta-analysis of five trials involving a total of more than 12 000 patients. However, as the authors correctly point out, LMWH could be preferred for its theoretical pharmacokinetic advantages.
Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial
Overview—Non-invasive ventilation (NIV) has been shown to be effective in reducing the need for intubation and the mortality associated with acute exacerbations of chronic obstructive pulmonary disease (COPD) in an intensive care setting. The authors attempted to determine whether the early introduction of NIV for acute exacerbations of COPD in the general respiratory ward would reduce the need for intubations and improve mortality.
Design—This was a multicentre randomised controlled trial, involving a total of 236 patients with mild to moderate acidosis prospectively recruited from 14 hospitals in the UK. Half of the patients were randomised to receive NIV, the other half to receive standard treatment.
Main outcome measures—The primary outcome measures were death and requirement for tracheal intubation (defined by strict failure criteria). Secondary outcome measures were improvement in breathlessness, respiratory rate, pH and pCO2 at four hours after admission.
Main results—The use of NIV significantly reduced the need for tracheal intubation as defined by the failure criteria. Thirty two of 118 (27%) of the standard group failed, compared with 18 of 118 (15%) of the NIV group (p=0.02). Inhospital mortality was also reduced by NIV, 24 of 118 (20%) died in the standard group compared with 12 of 118 (10%) in the NIV group (p=0.05). Also, NIV led to a more rapid improvement in pH in the first hour (p=0.02), a greater fall in the respiratory rate at four hours (p=0.035), and a reduction in the duration of breathlessness (p=0.025).
Conclusions—The authors concluded that patients with COPD can be managed effectively in the general respiratory ward with the introduction of NIV. They pointed to a marked reduction in the requirement for tracheal intubation and inhospital mortality for these patients.
Critique—The study has the considerable advantage over previous studies of having used very clear inclusion criteria for those admitted with acute exacerbation of COPD. Patients were admitted into the trial if the respiratory rate was over 23/min, Paco2 greater than 6 kPa, with a pH between 7.25 and 7.35. The exclusion criteria were also clear (low GCS, pneumothorax or where active treatment was deemed inappropriate). Randomisation was sound and there seemed to be independent statistical analysis. Although the primary outcome measures were clear, the secondary outcome measures were more subjective (including mask discomfort and breathlessness).
Availability of intensive care beds for patients with acute exacerbations of COPD within the UK health care system seems to be currently somewhat limited. NIV seems to have the potential to reduce demands on intensive care facilities while providing effective management for some patients with COPD. Widespread implementation of NIV would require extra training of the nursing staff. This paper has tackled a very important issue, and has provided a realistic solution for managing patients with COPD in our health care system.
Prospective audit of incidence of prognostically important myocardial damage in patients discharged from emergency department
This was a prospective observational study of patients presenting with chest pain of uncertain origin to a district general hospital accident and emergency (A&E) department. Some 110 of a possible 160 patients meeting the study's criteria were reviewed by a single clinician within 48 hours of their A&E attendance, having had cardiac causes of chest pain “ruled out” clinically and electrocardiologically. At review, the patients were re-examined, had a repeat ECG and blood taken for cardiac troponin T. All repeat ECGs were said to be “normal”, but eight patients (7%) had detectable troponin T. In seven patients, troponin T levels exceeded 0.1 μg/l, indicating myocardial damage. All seven patients were referred for urgent cardiology follow up.
Comment—The findings of this study are consistent with those of previous studies that have shown that myocardial infarction is relatively frequently “missed” in A&E. This study nicely focuses upon troponins at a time when their measurement is playing an increasing role in the investigation of patients who present as an emergency with chest pain. It is worth noting that troponin T is not completely specific for myocardial ischaemic injury. Given its long half life, it might have been interesting if the authors had also measured troponin T levels in blood taken at the time of the initial presentation, as this might have uncovered problems that actually predated attendance at the emergency department. One major criticism of this paper is that the patient selection criteria excluded patients who were discharged with disorders believed to be of gastrointestinal origin. Troponin levels on these patients may have yielded further interesting results.
Evaluation of the utility of computed tomography in the initial assessment of the critical care patient with chest trauma
This was a prospective observational study of patients presenting with chest injuries to a level III Spanish trauma centre (equivalent to a Level I US trauma centre). The study was designed to investigate whether or not early thoracic computed tomography (CT) in chest trauma patients improves eventual outcome. The results confirmed that thoracic CT did detect more injuries in chest trauma patients than did conventional chest radiographs. However, there was no demonstrable effect on the final outcome of these patients in terms of mortality, time spent on mechanical ventilation or in intensive care.
Blunt splenic injuries: dedicated trauma surgeons can achieve a high rate of non-operative success in patients of all ages
This study focuses upon the non-operative management (NOM) of blunt splenic trauma. The conclusions drawn from the management of 251 consecutive patients with blunt splenic trauma to a Level I US trauma centre challenge two pieces of oft quoted dogma in relation to the NOM of blunt splenic trauma. It has previously been suggested that blunt splenic trauma in the paediatric population should be only managed by paediatric surgeons and that NOM is not feasible for those above 50 years of age. However, the findings of this study suggest that advanced age is not a contraindication when considering NOM of blunt splenic injury and furthermore that paediatric injuries can be managed safely by appropriately trained non-paediatric trauma surgeons.
Open or closed diagnostic peritoneal lavage for abdominal trauma? A meta-analysis
This meta-analysis attempts to determine whether it is preferable to use an open or closed technique when performing diagnostic peritoneal lavage (DPL) for abdominal trauma. Seven randomised control trials comparing open and closed DPL (involving a total of 1126 patients) were identified from a search of the English language literature between 1977 and 1999. Meta-analysis revealed that closed DPL is comparable to open DPL in terms of accuracy and major complications. However, the advantage of a reduced time taken to perform closed DPL seemed to be offset by increased rates of technical difficulties and failure, requiring conversion to open DPL. The authors therefore conclude that an open method should be preferred to a closed one, but acknowledge that the role of DPL sesms to be diminishing because of increasing use of other investigations (such as ultrasound).
Bilateral simultaneous atraumatic quadriceps tendon ruptures associated with “pseudogout”
This case report serves as a reminder that “atraumatic” quadriceps tendon rupture can be difficult to diagnose and that such failure of diagnosis can result in even more difficulty in trying to treat it. A 58 year old diabetic gentleman is described whose initial presentation was to his general practitioner with a history of both knees suddenly giving way while walking. An initial diagnosis of peripheral neuropathy was made and the patient was started on an intensive rehabilitation programme. There was no improvement. He presented to accident and emergency with a painful swollen left knee three months after his initial complaint. A provisional diagnosis of septic arthritis was made. A septic screen was arranged, which proved negative. An aspirate of fluid from the knee joint showed a large number of calcium pyrophosphate crystals. Screening of the other knee confirmed a complete rupture of quadriceps tendon with presence of calcium pyrophosphate in the joint. Spontaneous rupture of the quadriceps tendon is generally believed to be attributable to weakening as a result of degenerative changes or repeated minor trauma, although there are previous associations in the literature with gout and hyperparathyroidism. Bilateral simultaneous quadriceps tendon rupture is a rare injury and in this patient was attributed to pseudogout.
Sudden cardiac death during sport and recreational activities in Israel
This retrospective review of sudden cardiac death during strenuous physical activity in Israel serves as a reminder of the possibility of atherosclerotic cardiovascular disease in the relatively young. Unsurprisingly, atherosclerotic cardiovascular disease was found to be responsible for the majority of sudden cardiac deaths during sport in people aged 35 years and over. It was, however, also the second most frequent cause of death (after cardiomyopathy) in those aged less than 35 years.
Purtscher's retinopathy was described in 1912, as multiple superficial white retinal patches and retinal haemorrhages surrounding a normal optic disc, attributed to a sudden increase in intracranial pressure transmitted to the optic nerve. This report describes the case of a 38 year old woman who presented to accident and emergency after a high speed road traffic collision. The patient sustained a seatbelt injury to her chest wall, but no other obvious direct limb or facial injuries. On detailed examination and screening, she was found to have a skull fracture, but computed tomography of the head was normal. Chest radiological findings were consistent with lung contusion and there was a wedge fracture of the thoracic spine. Subsequently she developed a scotoma of the left eye on the contralateral side to her skull fracture. Visual acuity testing revealed a marked deficit (reduced to finger counting), with an associated central visual field loss. There was no afferent papillary defect. Fundoscopy of the eye confirmed multiple retinal haemorrhages, cotton wool spots and “Purtscher flecken” close to optic disc. These areas of optic disc whitening are attributable to occlusion of deeper retinal capillary beds. Her visual acuity improved to 6/18 after some time. It was postulated that this woman developed retinal changes as a result of chest wall compression causing either a momentary increase in central venous (and hence retinal venous) pressure or a sudden increase in intracranial pressure transmitted to the optic nerve (Purtscher's retinopathy), or both.