2010年2月26日 星期五


Lactate Clearance Measures Efficacy of Goal-Directed Therapy in Sepsis
Mortality did not differ significantly when lactate clearance or central venous oxygen saturation was used to measure tissue oxygen delivery.

Goal-directed resuscitation for severe sepsis focuses on three targets: (1) fluid resuscitation to a central venous pressure of 8–12 mm Hg, (2) pressure support to a mean arterial pressure of at least 65 mm Hg, and (3) adequate oxygen delivery (via blood transfusion, dobutamine infusion, or both) to central venous oxygen saturation (ScvO2) of at least 70%. Measurement of ScvO2, however, requires a special catheter. These authors tested the hypothesis that use of lactate clearance >10% is not inferior to use of ScvO2 70% for assessing the adequacy of oxygen delivery.

In a prospective study conducted at the emergency departments of three U.S. medical centers, 300 patients with severe sepsis and septic shock were randomized to resuscitation to a target central venous pressure of 8–12 mm Hg, mean arterial pressure of >65 mm Hg, and either ScvO2 70% or lactate clearance >10% at 2 hours after initiation of resuscitation. The primary outcome was absolute in-hospital mortality. Overall, 23% of patients in the ScvO2 group died, compared with 17% in the lactate clearance group; the 6% difference between groups did not reach the predetermined statistical threshold of a 10% difference. Rates of adverse events were similar between groups.

Early goal-directed therapy in patients with sepsis reportedly decreases mortality by as much as 46%, but the need for a special catheter to measure ScvO2 can be an obstacle to its implementation. This study's findings suggest that a serum lactate decrease of 10% within 2 hours after initiation of sepsis resuscitation is not inferior to an ScvO2 of 70% for measuring adequate oxygen delivery and that lactate measurement might substitute for ScvO2 measurement.

Diane M. Birnbaumer, MD, FACEP
Dr. Birnbaumer works in the same department as Dr. Lewis, the editorialist. However, Dr. Lewis did not participate in Dr. Birnbaumer's coverage of this article.
Published in Journal Watch Emergency Medicine February 26, 2010

Jones AE et al. Lactate clearance vs central venous oxygen saturation as goals of early sepsis therapy: A randomized clinical trial. JAMA 2010 Feb 24; 303:739.
Lewis RJ. Disassembling goal-directed therapy for sepsis: A first step. JAMA 2010 Feb 24; 303:777.

Scabies 之治療

What is the best approach for treating classical scabies?
For classical scabies, the authors recommend two applications of topical permethrin 5% — one on day 1 and one between day 8 and day 15. The drug should be applied in the evening and left on overnight. Two doses of oral ivermectin (200 µg/kg/dose), taken with food — one on day 1 and one between day 8 and day 15 is an alternative strategy.

When should ivermectin be used to treat scabies?
Ivermectin should be used in combination with topical permethrin 5% to treat crusted scabies. Ivermectin can also be used as a single dose to treat close contacts, or as an alternative to permethrin treatment in patients with classical scabies. Ivermectin is not approved for this indication by the Food and Drug Administration.

How should pregnant women with scabies be treated?
Topical 5% permethrin can be administered to pregnant women. It is recommended that ivermectin and lindane not be used during pregnancy.


何謂 scabies?

Scabies is an ectoparasitic infection caused in humans by the scabies mite Sarcoptes scabiei variety hominis. Infection occurs as a result of direct skin-to-skin contact; fomite transmission from mites attached to clothing, bedding, and towels is uncommon. It is endemic in many impoverished communities.

What anatomical locations are most frequently affected by scabies?
In its classic presentation, lesions of scabies are most often present on the interdigital finger webs and flexor surfaces of the wrists. Elbows, axillae, buttocks, and genitalia are quite frequently involved as well, as are the breast areolae in women. Atypical presentations such as involvement of the scalp can occur in infants and the elderly.


2010年2月23日 星期二


Simple Measures Can Cut Catheter-Related Bloodstream Infections Significantly
Thousands of infections and deaths could be prevented.

Catheter-related bloodstream infections cause tens of thousands of deaths each year, and each infection costs tens of thousands of dollars to treat. In an earlier Michigan initiative (JW Gen Med Dec 27 2006) that involved 103 intensive care units (ICUs), rates of these infections were lowered dramatically after systematic implementation of five evidence-based interventions: washing hands, using full barrier precautions, cleaning the skin with chlorhexidine, avoiding the femoral site, and removing unnecessary catheters. Eighteen months after implementation, catheter-related bloodstream infections were reduced by two thirds from baseline. In this follow-up study that involved 90 of the original ICUs, investigators evaluated whether the lower incidence of such infections were sustained at 19 to 36 months after implementation (sustainability period).

Overall, data related to more than 1500 ICU months and 300,000 catheter-days during the sustainability period were reported. The mean rate of catheter-related bloodstream infections decreased from 7.7 per 1000 catheter-days at baseline to 1.3 per 1000 catheter-days at 16–18 months and to 1.1 per 1000 catheter-days at 34–36 months postimplementation. Compared with the baseline rate, mean bloodstream infection rates at 16–18 months and 34–36 months were significantly lower.

Implementing five simple evidence-based interventions significantly lowers catheter-related bloodstream infections. These results are sustainable after such interventions are integrated into practice. As the authors conclude, widespread implementation of these interventions could lower morbidity and costs associated with these infections substantially.

Paul S. Mueller, MD, MPH, FACP
Published in Journal Watch General Medicine February 23, 2010
Citation(s): Pronovost PJ et al. Sustaining reductions in catheter related bloodstream infections in Michigan intensive care units: Observational study. BMJ 2010 Feb 4; 340:c309. (http://dx.doi.org/10.1136/bmj.c309)

2010年2月5日 星期五


Muscle Relaxant Adds No Benefit to Ibuprofen for Cervical Strain
Pain relief did not differ among patients who received ibuprofen, cyclobenzaprine, or both drugs.

Muscle relaxants often are prescribed for neck and back pain, despite the lack of evidence of benefit. Researchers evaluated the effect of cyclobenzaprine in a prospective, randomized, double-blind study in a convenience sample of 61 adult patients (mean age, 34; 58% women) who presented to a level I trauma center emergency department with acute cervical strain (87% caused by motor vehicle collisions). Patients received ibuprofen (800 mg), cyclobenzaprine (5 mg), or both drugs three times daily for up to 7 days, as needed for pain. All patients received an initial dose of 800 mg of ibuprofen in the ED.

Patients rated pain severity on a 100-mm visual analog scale 30 to 60 minutes after taking the morning dose of medication. Pain scores improved significantly over 7 days in all three groups and did not differ among groups. Adverse effects were minimal and included dizziness in four patients who received cyclobenzaprine alone or with ibuprofen and nausea in one patient who received ibuprofen alone.

A small dose of cyclobenzaprine was used in this study, perhaps to avoid the anticholinergic, antihistaminic, and sedative side effects of this drug, which is closely related chemically to tricyclic antidepressants. No convincing evidence supports the use of cyclobenzaprine in painful musculoskeletal conditions, and the drug's benefit-to-adverse effect profile therefore argues against prescribing it. Most patients with cervical strain will get better. Provide adequate analgesia as needed, and leave the cyclobenzaprine in the pharmacy.

Kristi L. Koenig, MD, FACEP
Published in Journal Watch Emergency Medicine February 5, 2010

Citation(s): Khwaja SM et al. Comparison of ibuprofen, cyclobenzaprine or both in patients with acute cervical strain: A randomized controlled trial. CJEM 2010 Jan; 12:39.

2010年2月4日 星期四

Septic Shock, Insulin, and Steroids

Intensive insulin therapy did not lower in-hospital mortality in septic shock patients who received hydrocortisone.

In a study published in 2002, patients with septic shock and impaired adrenal reserve appeared to benefit from 7-day courses of hydrocortisone (50 mg every 6 hours) plus the mineralocorticoid fludrocortisone (JW Gen Med Aug 30 2002). In contrast, hydrocortisone alone was not beneficial in the 2008 CORTICUS trial (JW Gen Med Jan 9 2008). Because patients in the 2002 trial were sicker and were treated earlier than those in CORTICUS, some experts still recommend low-dose hydrocortisone for patients with severe sepsis and refractory hypotension.
That hydrocortisone invariably induces hyperglycemia raises another question: Is intensive insulin therapy appropriate for hydrocortisone-treated patients with septic shock? To answer this question, researchers in France randomized 509 such patients to receive either intensive insulin therapy (target glucose level, 80–110 mg/dL) or usual care (target glucose level, around 150 mg/dL). In addition, to examine whether mineralocorticoid therapy is beneficial, the researchers randomized the same patients to receive or not to receive fludrocortisone in a 2x2 factorial design. The outcome: Overall in-hospital mortality was 44%; neither intensive insulin nor fludrocortisone lowered mortality or any of numerous secondary endpoints.

In this multicenter study of hydrocortisone-treated patients with septic shock, intensive insulin therapy did not improve outcomes. An editorialist notes that (1) mean glucose levels in intensively treated patients fell short of the intended target, reaching only about 120 mg/dL, which was not markedly different from the mean glucose level (about 150 mg/dL) of the control group; and (2) the trial was underpowered to identify small differences in mortality. Thus, she calls for a much larger trial. My own sense, however, is that intensive glycemic control is not the magic bullet that will improve outcomes in septic shock patients and that research should be directed toward other pathophysiologic mechanisms.

Allan S. Brett, MD
Published in Journal Watch General Medicine February 4, 2010

The COIITSS Study Investigators. Corticosteroid treatment and intensive insulin therapy for septic shock in adults: A randomized controlled trial. JAMA 2010 Jan 27; 303:341.
Van den Berghe G. Should glucocorticoid-induced hyperglycemia be treated in patients with septic shock? JAMA 2010 Jan 27; 303:365.

2010年2月3日 星期三

Jet Lag

Jet lag is a recognized sleep disorder that results from crossing time zones too rapidly for the circadian clock to keep pace. The pathophysiology involves a temporary misalignment between the circadian clock and local time.

How can the circadian rhythm be re-entrained after travel?
A traveler may be able to accelerate re-entrainment of the circadian rhythm by intentionally seeking out bright light at the optimal times of the day. A simple recommendation for travel across six to eight time zones is to seek exposure to bright light in the morning after eastward travel and in the evening after westward travel. It may also be useful to avoid light when exposure would impede adaptation; for example, it may be helpful for a traveler to stay indoors for the first few hours of daylight after long eastward flights or for a few hours before dusk after long westward flights. The timing of sleep does not, in itself, reset the clock.

How should sleep be strategically scheduled after travel?
Shifting one's sleep schedule by 1 or 2 hours towards congruence with the destination time zone before departure may shorten the duration of jet lag. Most travelers will be sleep-deprived after an overnight flight and will require extra (recovery) sleep on the first day or two after arrival. On subsequent days, short naps are effective in reducing daytime sleepiness, whereas longer daytime naps can undermine nighttime sleep, as well as reduce exposure to the re-entraining effects of light.

How should melatonin be used?
Melatonin can be considered to be a darkness signal. To promote shifting of the body clock to an earlier time after eastward travel, the author suggests that the traveler take 0.5–3 mg of melatonin at local bedtime nightly until he or she has become adapted to local time. For westbound travel, the author suggests taking 0.5 mg (low, short-acting dose) during the second half of the night until the traveler has become adapted to local time. Melatonin is not approved as a drug by the Food and Drug Administration (FDA).

Which hypnotics are most appropriate for use during flight?
Because there is limited opportunity to sleep during a flight, a hypnotic medication that has only a 2- to 3-hour duration of action (e.g., zaleplon) is preferred. A longer-acting sleeping pill (e.g., zolpidem or eszopiclone) could result in grogginess on arrival; a sleeping pill should not be taken if there is a risk of deep-vein thrombosis because the induced sleep may further increase that risk, and it should not be combined with alcohol.

Teaching topics from the New England Journal of Medicine - Vol. 362, No. 5, February 4, 2010