Monday, February 18, 2008

Lit Bits: February 18, 2008

From the recent medical literature...

1. Aspirin "resistance" and risk of cardiovascular morbidity: systematic review and meta-analysis

Krasopoulos G, et al. BMJ 2008;336:195-198.

Objective: To determine if there is a relation between aspirin "resistance" and clinical outcomes in patients with cardiovascular disease.

Design: Systematic review and meta-analysis.

Data source: Electronic literature search without language restrictions of four databases and hand search of bibliographies for other relevant articles.

Review methods: Inclusion criteria included a test for platelet responsiveness and clinical outcomes. Aspirin resistance was assessed, using a variety of platelet function assays.

Results: 20 studies totalling 2930 patients with cardiovascular disease were identified. Most studies used aspirin regimens, ranging from 75-325 mg daily, and six studies included adjunct antiplatelet therapy. Compliance was confirmed directly in 14 studies and by telephone or interviews in three. Information was insufficient to assess compliance in three studies. Overall, 810 patients (28%) were classified as aspirin resistant. A cardiovascular related event occurred in 41% of patients (odds ratio 3.85, 95% confidence interval 3.08 to 4.80), death in 5.7% (5.99, 2.28 to 15.72), and an acute coronary syndrome in 39.4% (4.06, 2.96 to 5.56). Aspirin resistant patients did not benefit from other antiplatelet treatment.

Conclusion: Patients who are resistant to aspirin are at a greater risk of clinically important cardiovascular morbidity long term than patients who are sensitive to aspirin.

BMJ Abstract:

Editorial: Carries a worse prognosis, but may be indicative of pre-existing higher risk

Aspirin has clear benefits in cardiovascular disease. It reduces total mortality, cardiovascular mortality, and cardiovascular morbidity in people with cardiovascular disease or those at high risk of the disease; it is also cheap, relatively safe, and easy to use. So why does aspirin fail to work in some people who take it as prescribed? Research on this clinical "resistance" to aspirin has tried to assess whether the effect on the in vitro activation of platelets depends only on the dose and type of antithrombotic agent given, or whether some people respond poorly ("resist") to a specific drug, as some people do to specific antibiotics. In the accompanying systematic review, Krasopoulos and colleagues assess whether resistance to aspirin is related to cardiovascular outcomes in people with cardiovascular disease.

To date, most research has focused on whether aspirin resistance really exists, whether antiplatelet resistance is specific to certain agents or classes of drug, and whether resistance carries a worse prognosis. Firstly, no accepted gold standard test to define aspirin resistance is available. This and other epidemiological considerations have led some authors to argue that what has been dubbed resistance is just part of normal (Gaussian) variability in pharmacokinetics and pharmacodynamics. Others admit that aspirin resistance exists but are doubtful about its prognostic importance. They think that a lack of response to aspirin could just be a proxy marker for more advanced pre-existing disease or less controlled traditional risk factors.

Krasopoulos and colleagues’ review analysed data from 20 studies and 2930 patients and found resistance to aspirin in 28% of people. Resistance was significantly more common in women and those with renal failure and was associated with a statistically and clinically significant increase in the risk of death or adverse cardiovascular events, at least in univariate analysis. However, they found no association between the dose of aspirin or concomitant use of other antiplatelet agents and adverse events. The review has some limitations including use of fixed effect methods and lack of pooled multivariable adjusted estimates. A similar review recently came to the same conclusions, however, confirming the external validity of Krasopoulos and colleagues’ review.

Despite this work several questions remain. We don’t know whether aspirin resistance is a true abnormal response or whether it reflects normal variability in drug activity. We also aren’t clear whether aspirin resistance has a negative prognostic effect independent of more traditional risk factors, such as diabetes or obesity. If aspirin resistance is an abnormal response that results in worse prognosis then what can clinicians do? We suggest that when aspirin resistance is suspected patients should be screened using available tests. Management of patients with aspirin resistance should include a comprehensive appraisal of thrombotic and bleeding risks, the likelihood of non-adherence to treatment, and access to other antiplatelet agents. On the basis of this assessment, several strategies can then be proposed. These include adding another antiplatelet agent (for people at high thrombotic risk and low bleeding risk), substituting aspirin with the more effective clopidogrel (for people at intermediate thrombotic risk and low bleeding risk), increasing the dose of aspirin (for example, to 325 mg/day in people at mildly increased thrombotic risk and low to intermediate bleeding risk), or continuing with the same antiplatelet regimen (for everyone at high bleeding risk).

The problem in finding truly scientific answers to the effectiveness of these strategies lies in the lack of randomised controlled clinical trials. This will probably change, however, as results from trials such as TREND-AR (tirofiban evaluation of surrogate endpoints in prevention of ischaemic complications during percutaneous interventions in patients with coronary disease and aspirin resistance) become available. This trial will randomise patients undergoing percutaneous coronary intervention who have documented aspirin resistance to a combination of clopidogrel, aspirin, heparin, and tirofiban (a potent antiplatelet agent) or clopidogrel, aspirin, and heparin. This trial, among others, will show whether aspirin resistance is just a non-modifiable risk factor (like age or sex) or whether more aggressive antithrombotic regimens are beneficial in patients with aspirin resistance.

Conducting more clinical trials will help fill in the gaps, but another potential reason exists for the interest in aspirin resistance. Drug companies may be keen to downgrade aspirin from its leading role as an effective drug in cardiovascular disease so that they can substitute it with much more expensive but marginally more effective alternatives.

Biondi-Zoccai G. BMJ 2008;336:166-167.

2. Watching Stressful Sporting Events May More Than Double Risk for CV Emergencies

Sports fans may face more than a doubling of risk for cardiovascular events while watching stressful matches, reports the New England Journal of Medicine.

The incidence of CV emergencies among German residents during World Cup matches involving the German team in 2006 was compared with the incidence during a control period. Overall, the risk for CV emergencies was significantly increased during soccer games (incidence ratio, 2.7), with the highest incidence during the first 2 hours of a match. Risk elevations were seen for ST-segment-elevation MI, non-STEMI/unstable angina, and cardiac arrhythmia.

Risk increases were significant regardless of gender or cardiovascular history, but were highest among men and those with a history of coronary artery disease.

The authors note: "Our results do not permit identification of the exact triggers ... lack of sleep, overeating, consumption of junk food, heavy alcohol ingestion, smoking, and failure to comply with the medical regimen should all be considered."

NEJM article (Free abstract; full text requires subscription):

3. Impact of Abdominal Helical CT on the Negative Appendicitis Rate

Kim K, et al. J Emerg Med. 2008;34:3-6.

Appendicitis is the most common cause of acute abdominal pain requiring surgical treatment in patients presenting to Emergency Departments (EDs), with an annual incidence of 250,000 cases in the United States. For many decades, clinical evaluation has been the mainstay for the diagnosis of appendicitis, and physicians have relied on clinical judgment to make a timely diagnosis. Diagnostic accuracies vary depending on the clinical experience of the surgeon involved, and are reported to range from 71% to 97%.

Several recent studies have identified helical computed tomography (CT) scan as the diagnostic imaging test of choice for evaluating patients with suspected appendicitis. Given the recent advances in CT technology, the abdomen and pelvis can be visualized in a relatively short period of time with thin slice multi-detector CT scanners. Accordingly, a number of authors recommend the routine use of CT for all patients with acute right lower quadrant abdominal pain, whereas others suggest that imaging may cause unnecessary delays in treatment. For such reasons, many EDs have different policies concerning the use of CT scan for the diagnosis of acute appendicitis. Some centers rely heavily on CT scan for the diagnosis of appendicitis whereas others still depend on physicians’ opinions.

Many investigations have been conducted to evaluate the utility of CT scan in single emergency centers, and have used outcome measures, such as negative appendectomy rates or frequency of complications. Therefore, we conducted a multi-center comparative study to evaluate the impact of CT utilization on negative appendectomy rates. We hypothesized that the rates of CT utilization would be inversely related to negative appendectomy rates.

This study was conducted to assess the impact of helical computed tomography (HCT) on the rate of negative appendicitis. Patients were identified from a pathology department database that included all patients taken to the operating room with a preoperative diagnosis of appendicitis, and pathologic specimens were analyzed to determine the presence of appendicitis. Two time periods were studied, Period A prior to the arrival of HCT, and Period B several years after HCT was incorporated into the evaluation of suspected appendicitis.

The results showed that during period A, no patients received HCT and the negative appendicitis rate was 15.5%. In period B, 81.5% of patients received HCT and the negative appendicitis rate was 7.9%. In conclusion, there was a 48% decline in the rate of negative appendicitis found to be associated with the common use of HCT.


4. Care of the Bariatric Surgery Patient in the ED

Luber SD, et al. J Emerg Med 2008;34:13-20.

Abstract: Obesity has reached epidemic proportions in the United States, with an estimated 50% of adults meeting the definition of being overweight. As this condition has become more prevalent, bariatric surgery has become an increasingly accepted form of treatment of the severely obese. Patients who have had bariatric surgery are presenting more commonly to Emergency Departments as a result. This article will review the most common bariatric surgery procedures, the complications that can arise post-operatively, and the approach to the assessment and management of the bariatric surgery patient in the Emergency Department.

Full-text (subscription required):

5. Antiplatelet Therapy in Management of TIA: Overview and Evidence-based Rationale

Ovbiagele B. J Emerg Med 2008; in press.

Abstract: As many as 300,000 transient ischemic attacks (TIAs) occur in the United States each year, accounting for 0.3% of all Emergency Department visits. An under-recognized and under-treated problem, TIA is associated with up to a 10% risk of subsequent stroke within 7 days and a 25% risk of death at 1 year. Antiplatelet therapy can result in significant reductions in secondary stroke risk. However, nearly 50% of patients with TIA leave the Emergency Department without any medication. This article discusses recent results from major antiplatelet clinical trials in stroke prevention and highlights the need for appropriate and timely initiation of antiplatelet treatment in patients with TIA.

Full-text (subscription required):

6. Does intraosseous equal intravenous? A pharmacokinetic study

Von Hoff DD, et al. Amer J Emerg Med. 2008;26:31-38.

Study Objective
Despite the growing popularity of intraosseous infusion for adults in emergency medicine, to date there has been little research on the pharmacokinetics of intraosseously administered medications in humans. The objective of the study was to compare the pharmacokinetics of intraosseous vs intravenous administration of morphine sulfate in adults.

The study followed a prospective, randomized, crossover design. Each subject was equipped with an indwelling intraosseous access device and an intravenous line. Subjects were randomized to receive a 5-mg bolus of morphine sulfate infused intraosseously or intravenously, followed by the alternate administration route 24 hours later.

Serial venous blood samples (5 mL) were taken at baseline and at 13 time points over 8 hours postinfusion. Blood samples were analyzed for morphine concentration by radioimmunoassay. Pharmacokinetic parameters were calculated from the data, including maximum plasma concentration (Cmax), time to maximum concentration (Tmax), and area under plasma concentration-time curve (AUC), among others. Data were analyzed by analysis of variance.

No statistically significant differences were observed between intraosseous and intravenous administration of morphine sulfate for nearly all of the pharmacokinetic parameters including Cmax (235 ± 107 vs 289 ± 197 ng/mL, mean ± SD, IO vs IV, respectively), Tmax (1.3 ± 0.5 vs 1.4 ± 0.5 minutes), and AUC(0-∞) (4372 ± 1785 vs 4410 ± 1930 ng min−1 mL−1). There was, however, a statistically significant difference in the volume of distribution in the central compartment, Vd (P = .0247), which in the opinion of the investigators was thought to be due to a minor deposition effect near the intraosseous port or in the bone marrow.

The results support the bioequivalence of intraosseous and intravenous administration of morphine sulfate in adults.

7. Stroke After TIA

More than 15% of patients can be expected to have a stroke within 90 days of TIA presentation.

During the past five years, transient ischemic attack (TIA) has come to be regarded as angina of the brain. This new thinking arose after observational studies raised awareness of the frequency of stroke after TIA, but the actual incidence is uncertain because of varying methodology in the relevant studies.

These authors performed a meta-analysis of 11 studies that included a combined total of more than 7000 patients. To determine if a stroke occurred after the index TIA event, some of the studies relied on record review (passive ascertainment) while other studies interviewed patients at predetermined intervals after the index event (active ascertainment). The latter method is thought to be more reliable.

The overall rate of stroke after TIA was 3.5% by 2 days, 8.0% by 30 days, and 9.2% by 90 days. When only the three studies that used active outcome ascertainment were analyzed, the corresponding rates were 9.9%, 13.4%, and 17.3%.

Comment: As the U.S. population ages, cerebrovascular disease will become much more prevalent. Emergency departments can play a significant role in stroke prevention by being attentive to symptoms that may represent cerebral ischemia and by ensuring that patients are evaluated promptly. A recent study (Ross, et al. Ann Emerg Med. 2007;50:109-119) showed that the work-up can be done safely and expeditiously in an ED observation unit.

— J. Stephen Bohan, MD, MS, FACP, FACEP. Published in Journal Watch Emergency Medicine January 18, 2008. Citation: Wu CM et al. Arch Intern Med 2007;167:2417.

8. Steroids in Meningitis

Benefit was seen in patients with definite disease but not in those with probable disease.

The evidence for benefit from steroids in bacterial meningitis is conflicting. During a 9-year period at a hospital for tropical diseases in Vietnam, 435 patients with suspected bacterial meningitis were randomized in double-blind fashion to receive either dexamethasone (0.4 mg/kg) or placebo twice a day for 4 days.

At the time of hospital discharge or death, 69% of patients were classified as having definite meningitis (positive blood or cerebrospinal fluid cultures or positive Gram stain) and 29% were classified as having probable meningitis (bacteria either not detected or cultured, and no alternative diagnosis).

Thirty days after randomization, mortality rates were 10% in the dexamethasone group and 12.4% in the placebo group. The relative risk for death in the dexamethasone group was 0.79. Subgroup analysis showed a greater benefit in patients with definite meningitis (RR, 0.43) and no benefit in those with probable meningitis, possibly because some patients in the latter group had tuberculous meningitis. At 6 months, disability and hearing loss were significantly less prevalent in the dexamethasone group. The most common etiologic organism was Streptococcus suis, which is common in Asia but not in North America.

Comment: When the results of the single European trial (de Gans J, et al. NEJM 2002;347:1549-1556) are added to these data, the evidence becomes strong enough to unequivocally recommend that adults with suspected meningitis be treated with steroids. Although S. suis was the most common cause of meningitis in this study, other species of streptococcus likely would have a similar response to treatment.

— J. Stephen Bohan, MD, MS, FACP, FACEP. Published in Journal Watch Emergency Medicine January 18, 2008. Citation: Mai NTH, et al. N Engl J Med;357:2431.

9. Exercise Capacity a Strong Predictor of Mortality in Men

Exercise capacity, measured by a treadmill test, strongly predicts men's risk for death, according to a large study released online in Circulation.

Nearly 16,000 male veterans — about 40% of them black — underwent treadmill exercise testing and then were followed for about 7.5 years. After adjustment for cardiac medications, age, and other risk factors, all-cause mortality risk fell by 13% for every 1-MET increase in exercise capacity.

Exercise capacity was a stronger predictor of death than were cardiovascular risk factors, age, or BMI. The findings were similar regardless of race or presence of cardiovascular disease.
The authors conclude that "exercise capacity should be given as much attention by clinicians as other major risk factors."

Circulation article (Free abstract; full text requires subscription):

10. Drinkable Tap Water is Suitable for Wound Cleansing

Laurie Barclay, MD. January 24, 2008 — Drinkable tap water applied topically is as effective as normal saline for cleansing a wound, according to a Cochrane review published in the January 23 issue of the Cochrane Database Systematic Reviews.

"Various solutions have been recommended for cleansing wounds, however normal saline is favoured as it is an isotonic solution and does not interfere with the normal healing process," write Ritin Fernandez, RN, MN, and Rhonda D. Griffiths. MSc, DrPH, from the University of Western Sydney in New South Wales, Australia. "Tap water is commonly used in the community for cleansing wounds because it is easily accessible, efficient and cost effective, however, there is an unresolved debate about its use."

Of 11 included trials, 7 compared rates of infection and healing in wounds cleansed with water vs normal saline, 3 trials compared cleansing vs no cleansing, and 1 trial compared procaine spirit vs water. Procaine spirit is a mixture of procaine HCl 2% with spirit 70% and is commonly prescribed for wound cleansing following surgery. Ability to pool the data was limited because there were no standard criteria across the trials for evaluating wound infection. The predominant comparisons were water vs normal saline and tap water vs no cleansing.

When chronic wounds were cleansed with tap water vs normal saline, the relative risk (RR) of developing an infection was 0.16 (95% confidence interval [CI], 0.01 - 2.96). Compared with saline, tap water was more effective in reducing the infection rate in adults with acute wounds (RR, 0.63; 95% CI, 0.40 - 0.99). In children, the use of tap water to cleanse acute wounds was not associated with a statistically significant difference in infection vs saline (RR, 1.07; 95% CI, 0.43 - 2.64).

When wounds were cleansed with tap water or not cleansed at all, there was no statistically significant difference in infection rates (RR, 1.06; 95% CI, 0.07 - 16.50). In a similar fashion, episiotomy wounds cleansed with water or with procaine spirit did not differ in infection rate. For cleansing open fractures, use of isotonic saline, distilled water, and boiled water was not statistically significantly different in the number of fractures that became infected.

"There is no evidence that using tap water to cleanse acute wounds in adults increases infection and some evidence that it reduces it," the review authors write. "However there is not strong evidence that cleansing wounds per se increases healing or reduces infection. In the absence of potable tap water, boiled and cooled water as well as distilled water can be used as wound cleansing agents. . . . The decision to use tap water to cleanse wounds should take into account the quality of water, nature of wounds and the patient's general condition, including the presence of comorbid conditions."

"While the findings of this review do not indicate adverse effects from the use of tap water, practitioners and health service managers should interpret the findings with caution as most of the comparisons were based on single trials, some of which do not report the methodology in sufficient detail to enable assessment of quality," the review authors conclude. "The availability and cost of resources may also determine which solution is used for cleansing wounds in different settings."

Cochrane Database Syst Rev. 2008:

11. High Adverse-Event Rates Seen Within 90 Days After Stopping Clopidogrel

Adverse events may cluster in the 90 days after patients stop taking clopidogrel, JAMA reports.
The study involved some 3000 patients who, after being treated for acute coronary syndromes with medical therapy alone or percutaneous coronary intervention, were discharged from a Veterans Affairs hospital and prescribed clopidogrel. The mean duration of clopidogrel therapy was about 300 days.

In the months after clopidogrel discontinuation, all-cause mortality or acute MI occurred in 17% of medically treated patients and 8% of PCI-treated patients. After multivariable adjustment (including length of clopidogrel therapy), risk in both groups was nearly twice as high during the 90 days after stopping clopidogrel than days 91 through 180.

In Journal Watch Cardiology, JoAnne Foody notes that until these findings are confirmed, "clinicians should do their best to ensure that patients take their prescribed clopidogrel." She adds that extending clopidogrel treatment may improve outcomes in patients with high thrombosis risk and low bleeding risk.

JAMA article (Free abstract; full text requires subscription):

12. Acute Hypertension (over 180/110): An Undertreated Condition

from Heartwire — a professional news service of WebMD. February 11, 2008 (Honolulu, HI) – The enormous inadequacy in the management of patients with acute hypertension has been highlighted by a new registry study, which found that despite having a mortality rate similar to acute coronary syndromes or acute heart failure, many patients with this condition are not even followed up after their initial treatment.

Lead author of the study, Dr Chris Granger (Duke University Medical Center, Durham, NC), explained that acute hypertension is defined as blood pressure over 180/110 mm Hg, and the recommended treatment is IV antihypertensive drugs to get the blood pressure down to target levels. "This is a really understudied and undertreated condition--there is really very little information out there on the best way to treat it. So we conducted a registry to better understand acute hypertension. We wanted to find out who these patients are, how they are managed, what their outcomes are like, and what the causes and consequences of acute hypertension are. This is the first time this has been looked at in a multicenter study," he told heartwire.

Initial results from the STAT registry, sponsored by The Medicines Company, were presented last week at the 37th Critical Care Congress of the Society of Clinical Care Medicine (SCCM), held February 2-6, 2008 in Honolulu, HI. The study is aiming to collect data for as many as 120 consecutive patients in each of 25 US hospitals (with a target enrollment of more than 1500 patients), and to date, 982 patients have been enrolled from 21 hospitals.

A major problem

Granger noted that their most important finding was that this is a major problem, and there are major opportunities to improve care. In some areas of the southeastern US, as many as 25% of patients in some urban emergency departments have acute hypertension, he reported. He said the population involved was "more or less what we would expect"--around half were African American, the average age was 58, 90% had a history of chronic hypertension, 25% were nonadherent to prescribed medication, 30% had had a prior hospitalization for acute hypertension, and most presented to the emergency department with symptoms such as chest pain, shortness of breath, and symptoms of stroke, and one-third of them were actually having a stroke.

Many IV drugs were used for treatment, including labetalol, metoprolol, hydralazine, nitroglycerin, nicardipine, and sodium nitroprusside, and two or three different drugs were often used in the same patient. Despite this, it took a long tome to get the blood pressure down--for patients without subarachnoid hemorrhage, the median time to achieve a systolic pressure of below 160 mm Hg was four hours, and there was a high rate of overshooting, with 4% of patients developing hypotension, necessitating intervention. There was also a very high rate of recurrence, with 52% of patients having reelevation of systolic blood pressure to over 180 mm Hg after initial control.

For the 92 patients presenting with subarachnoid hemorrhage, the median time to achieve a systolic pressure below 140 mm Hg was 1.5 hours, and 6.5% developed hypotension. There was considerable variability in blood-pressure response over time, based upon the initial antihypertensive agent selected. The median duration of IV therapy was 10.5 hours, and most patients (58%) had evidence of target-organ injury associated with their hypertensive episode.

These patients had a very high rate of mortality--8% at 90 days, which Granger points out is the same as for acute coronary syndromes or acute heart failure. In addition, 40% of patients were rehospitalized within 90 days.

He added that "a very concerning finding" was that 60% of these patients either had no evidence of a follow-up appointment or did not attend the follow-up appointment. "So despite the fact these patients have a life-threatening condition, they are not being followed up well at all. There is room for a large improvement here," he commented.

13. Does This Child Have a Urinary Tract Infection?

Shaikh N, et al. JAMA. 2007;298:2895-2904.

Context: Urinary tract infection (UTI) is a frequently occurring pediatric illness that, if left untreated, can lead to permanent renal injury. Accordingly, accurate diagnosis of UTI is important.

Objective: To review the diagnostic accuracy of symptoms and signs for the diagnosis of UTI in infants and children.

Data Sources: A search of MEDLINE and EMBASE databases was conducted for articles published between 1966 and October 2007, as well as a manual review of bibliographies of all articles meeting inclusion criteria, 1 previously published systematic review, 3 clinical skills textbooks, and 2 experts in the field, yielding 6988 potentially relevant articles.

Study Selection: Studies were included if they contained data on signs or symptoms of UTI in children through age 18 years. Of 337 articles examined, 12 met all inclusion criteria.

Data Extraction: Two evaluators independently reviewed, rated, and abstracted data from each article.

Data Synthesis: In infants with fever, history of a previous UTI (likelihood ratio [LR] range, 2.3-2.9), temperature higher than 40°C (LR range, 3.2-3.3), and suprapubic tenderness (LR, 4.4; 95% confidence interval [CI], 1.6-12.4) were the findings most useful for identifying those with a UTI. Among male infants, lack of circumcision increased the likelihood of a UTI (summary LR, 2.8; 95% CI, 1.9-4.3); and the presence of circumcision was the only finding with an LR of less than 0.5 (summary LR, 0.33; 95% CI, 0.18-0.63). Combinations of findings were more useful than individual findings in identifying infants with a UTI (for temperature above 39°C for greater than 48 hours without another potential source for fever on examination, the LR for all findings present was 4.0; 95% CI, 1.2-13.0; and for temperature less than 39°C with another source for fever, the LR was 0.37; 95% CI, 0.16-0.85). In verbal children, abdominal pain (LR, 6.3; 95% CI, 2.5-16.0), back pain (LR, 3.6; 95% CI, 2.1-6.1), dysuria, frequency, or both (LR range, 2.2-2.8), and new-onset urinary incontinence (LR, 4.6; 95% CI, 2.8-7.6) increased the likelihood of a UTI.

Conclusions: Although individual signs and symptoms were helpful in the diagnosis of a UTI, they were not sufficiently accurate to definitively diagnose UTIs. Combination of findings can identify infants with a low likelihood of a UTI.

14. Hypovolemic Shock Evaluated by Sonographic Measurement of the IVC During Resuscitation in Trauma Patients

Yanagawa Y, et al. J Trauma 2007;63:1245-1248.

Background: Inferior vena cava (IVC) diameter immediately after fluid resuscitation has not yet been investigated in trauma patients with shock on arrival.

Methods: Between June 2004 and May 2005, 30 trauma patients with hemorrhagic shock were prospectively investigated. Using ultrasound, we measured maximum anterior-posterior diameter of the IVC just below the diaphragm in the hepatic segment, in the expiratory phase. This was performed on arrival and when systolic blood pressure had been raised to over 90 mm Hg by fluid resuscitation in the emergency room. Subjects were divided into two groups: a transient responder group (n = 17) in which shock recurred after leaving the emergency room and a responder group (n = 13) in which blood pressure remained stable.

Results: There were no significant differences between the two groups regarding age or gender, or regarding vital signs or IVC diameter on arrival. Average injury severity score in the transient responder group was significantly greater than that in the responder group. After fluid resuscitation, no significant intergroup differences were observed regarding vital signs. However, IVC diameter was significantly smaller in the transient responder group than in the responder group (6.5 +/- 0.5 mm; mean +/- SE vs. 10.7 +/- 0.7 mm, p less than 0.05).

Conclusion: In trauma patients, inadequate dilatation of the IVC by fluid resuscitation might indicate insufficient circulating blood volume despite normalization of blood pressure. In this small study, IVC diameter appeared a better predictor of recurrence of shock than blood pressure, heart rate, or arterial base excess. A larger prospective study is called for to clearly establish the sensitivity and specificity of this method.

15. Isolated Thoracolumbar Transverse Process Fractures Are Simply That

These fractures are markers of thoracic, intra-abdominal, and retroperitoneal visceral injuries but not of other injuries to the bony spinal column.

Isolated thoracolumbar spine transverse process fractures do not undermine the integrity of the three-column vertebral support system, but they are associated with structurally unstable thoracolumbar spine fractures in 10% to 20% of patients. Plain radiographs miss these unstable thoracolumbar bony injuries in about 10% of cases. In a retrospective study of trauma-registry data, researchers analyzed characteristics of isolated thoracolumbar transverse process fractures discovered by 16-slice computed tomography (CT) at a single level I trauma center between 2002 and 2005.

Of 314 patients with thoracolumbar transverse process fractures, 248 had isolated fractures. In the group with isolated fractures, 72% were male, 89% sustained blunt mechanisms of injury, and the mean Injury Severity Scale score was 19. Forty-four percent of patients had one thoracolumbar transverse process fracture, 21% had two, 14% had three, 12% had four, and 9% had five to nine fractures. Visceral chest injuries were present in 29% of patients, abdominal injuries in 28%, chest and abdominal injuries in 11%, and pelvic fractures in 33%. Spine consultation and follow-up did not result in the discovery of any new thoracolumbar fractures or neurological damage, and no further studies were required.

Comment: This study demonstrates that thoracolumbar transverse process fractures reflect significant torso trauma and are associated with a considerable incidence of intra-abdominal and pelvic injuries. Although the study cohort was relatively small, the findings suggest that, particularly with today’s higher-resolution 128- and 256-slice scanners, isolated thoracolumbar transverse process fractures identified by CT do not require neurosurgical or orthopedic consultation, log-roll precautions, or additional imaging.

— John A. Marx, MD. Published in Journal Watch EM February 8, 2008. Citation: Homnick A, et al. Isolated thoracolumbar transverse process fractures: Call physical therapy, not spine. J Trauma 2007 Dec; 63:1292.

16. 'Choking Game' Has Caused 82 Juvenile Deaths Since Mid-'90s

At least 82 children have died of accidental strangulation attributed to the "choking game" since 1995, according to the CDC.

A report in MMWR describes the first attempt to assess the incidence of deaths among youths playing this game — strangulation, often with a noose, to achieve brief euphoria by cerebral hypoxia. In the cases, found through newspaper articles and choking-game awareness websites, 87% of the victims were male, and the mean age was 13.

An editorial note recommends that healthcare providers watch for warning signs, including mention of the choking game, bloodshot eyes, marks on the neck, frequent severe headaches, disorientation after spending time alone, and ropes or belts tied to bedroom furniture or doorknobs.

"Although asphyxial games might have been played by youths for generations, the use of a ligature while playing alone appears to be a new practice that can be fatal," it says.

MMWR article (Free):

17. Clot aspiration a promising alternative to conventional PCI

Svilaas T, et al. N Engl J Med 2008;358:557-67.

The usual way to unblock a coronary artery is to dilate it with a balloon. Balloon dilation restores blood flow but can also release thromboembolic material that clogs up vessels further downstream. An alternative approach is to suck out the clot directly. In a randomised trial comparing the two techniques, the newer one worked better in patients with myocardial infarction. Direct aspiration significantly improved downstream myocardial perfusion and led to more complete resolution of ST segment elevation on post-procedure electrocardiograms. Both groups of patients received bare metal stents after their allocated percutaneous coronary intervention (PCI).

Aspiration of the thrombus didn’t improve survival significantly during the first 30 days (11 of 529 patients died (2.1%) v 21 of 531 (4.0%); risk ratio 0.52, 95% CI 0.26 to 1.07). Instead, the authors reported a significant association between better myocardial perfusion and a lower risk of death, further infarction, or revascularisation. Further trials will need to confirm these findings.

Two thirds of the aspirated clots were made exclusively of platelets, confirming the importance of antiplatelet drugs, says an editorial (p 634). These patients had the recommended aspirin, clopidogrel, and abciximab before PCI, then aspirin and clopidogrel afterwards.

NEJM Abstract:

18. Systematic Reviews Don’t Have all the Answers

Qayyam R, et al. Ann Intern Med 2008;148:186-96; MacLean C, et al. Ann Intern Med 2008;148:197-213; Wilt TJ, et al. Ann Intern Med 2008 Feb 4; [Epub ahead of print]

Systematic reviews and meta-analyses are most useful when they give definitive answers to clinically relevant questions, such as does this treatment work, and if so is it better or safer than other treatments? More often than not, however, researchers, doctors, and patients must make do with the far less satisfactory conclusion that we still don’t know because the research is weak and full of holes.

Three separate systematic reviews in the same journal recently ran aground trying to find the best treatments for early prostate cancer and osteoporosis, and the best strategy for treating acute coronary syndrome. In each case, the authors looked carefully for all the relevant studies, appraised their quality, extracted data, and tried to synthesise the evidence. Between them they looked at more than 600 studies that involved thousands of patients. In all three reviews, the data were simply not good enough to direct doctors to one treatment or the other, usually because there were too few head to head trials. Reviewers found none comparing different treatments for osteoporosis and just three comparing treatments for early prostate cancer. The authors of the review comparing routine percutaneous coronary intervention with a more selective strategy for acute coronary syndrome found 10 head to head trials. But they were heterogeneous and not powerful enough to be conclusive, even when combined.

19. Heavy Fast Food Consumption Can Quickly Elevate ALT Levels

A single week of overindulging in fast food can lead to pathologic levels of alanine aminotransferase (ALT), according to a small study in Gut published early online.

Swedish researchers had 18 healthy adults eat at least two fast food meals a day, thereby doubling their calorie intake, and limit their daily exercise to less than 5000 steps for 4 weeks. A matched control group continued their usual diet and exercise.

The fast food group gained an average of 14 pounds. Over half of the people in that group experienced persistently elevated ALT levels from the first week to the end of the study. To explain this, the authors speculate that an increased supply of monosaccharides to the liver could have led to induction of the enzyme in hepatocytes.

They suggest that "in the clinical evaluation of subjects with elevated ALT, physicians should include not only questions about alcohol intake, but also explore whether recent excessive food intake has occurred."

Gut article abstract:

20. Sugary drinks, fruit, and increased risk of gout

BMJ 2008;336:285-286

Editorials: Dietary fructose could be a contributing factor

The accompanying prospective cohort study by Choi and Curhan adds dietary fructose intake to the list of possible risk factors for gout. Laboratory evidence that dietary fructose increases serum urate already exists, and recent epidemiological studies have found an association between dietary fructose and hyperuricaemia in the United States.

The health professionals follow-up study was established in 1986 to examine the relation between nutritional factors and disease onset in later life in more than 50,000 American men. Previous analyses have looked at the association of obesity, alcohol, and diet with the onset of gout.

This new analysis looks at the role of non-alcoholic drinks and fruit on the first onset of gout. It finds a strong association between sugar sweetened soft drinks, usually containing fructose, and gout. Consuming two servings a day of a sugar sweetened soft drink increased the risk of developing gout by 85% (relative risk 1.85, 95% confidence interval 1.08 to 3.16). This compares with an increased risk of 49% from drinking 15-29.9 g/day of alcohol, 21% from eating an extra serving of meat a day, and 95% from having a body mass index of 25.0-29.9 versus 21.0-22.9; consuming 240 ml of skimmed milk a day decreased risk by 43%. A high intake of naturally occurring fructose also increased the risk of developing gout; consuming two or more glasses of fruit juice each day increased the risk by 81% (1.81, 1.12 to 2.93) and eating an apple or orange a day increased the risk by 64% (1.64, 1.05 to 2.56). These epidemiological data provide useful information for formulating appropriate dietary advice that might reduce recurrent gout.

Choi article in BMJ:

21. Emergency Management of Chronic Pain and Drug-Seeking Behavior: An Alternate Perspective

Hawkins SC. J Emerg Med. 2008;34:125-129.

Pain is one of the most prevalent conditions treated by Emergency Physicians, although it remains contested how to interpret, measure, and treat this condition. In particular, there is controversy over how to identify and treat patients with chronic under-treated pain and those who are potentially malingering (drug-seeking). This article discusses currently accepted paradigms for treating potentially malingering patients, difficulties some communities may have when these paradigms are applied, and the results of implementing pain treatment guidelines that limit opioid use. Systematically limiting opioids via these guidelines was not associated with a decrease in overall patient satisfaction, patient satisfaction with pain management, overall volume, or volume of patients with potential drug-seeking diagnoses. Emergency Physicians’ perception of quality of care delivered, as well as job satisfaction, increased after implementation of the guidelines.