Peeing into the wind? Urine drug screens, part 2 (opiates)
Apart from benzodiazepines, the opiate urine drug screens (UDS) are probably the most frequently utilized and misunderstood.
Paucis Verbis: CHF likelihood ratios
A 50 y/o man with a history of CHF and COPD is brought in by ambulance in severe respiratory distress. He is sitting upright with a RR 30 and O2 saturation of 79% on room air. Is this a CHF or COPD exacerbation? This is a common dilemma faced in the ED. Fortunately there are likelihood ratios to help you risk stratify using a Fagan nomogram.
Note that there are 3 tables:
- All-comer Emergency Department (ED) patients1
- ED patients WITH a known history of asthma or COPD2
- Summative LRs for BNP are provided in ED patients with or without a history of asthma/COPD1
See the blue font for the likelihood ratios ≥ 3.0.
PV Card: Does Your Dyspneic Patient Have CHF?
Adapted from [1, 2]
Go to ALiEM (PV) Cards for more resources.
References
- Wang C, FitzGerald J, Schulzer M, Mak E, Ayas N. Does this dyspneic patient in the emergency department have congestive heart failure? JAMA. 2005;294(15):1944-1956. [PubMed]
- McCullough P, Hollander J, Nowak R, et al. Uncovering heart failure in patients with a history of pulmonary disease: rationale for the early use of B-type natriuretic peptide in the emergency department. Acad Emerg Med. 2003;10(3):198-204. [PubMed]
Trick of the Trade: Alternative to Word catheter for Bartholin abscess
Bartholin abscesses are challenging to manage, partly because of Word catheter insertion. Sometimes, the space is not large enough (unable to fit the catheter) or too large (catheter falls out). How else can you “pack” the abscess space?
(more…)
Peeing into the wind? Urine drug screens, part 1 (benzodiazepines)
Let’s be honest. When was the last time results from urine drug screens (UDS) changed your management plan? Many times it takes hours for the patient to give the urine sample anyway. And, with all of the false positives out there, how do we know what the heck the result is actually telling us?
(more…)
Paucis Verbis: Does this adult patient need blood cultures?
Do you order blood cultures for all your ED patients with a fever? Obviously no. What’s your decision making process on ordering this test? There are really no findings or tests with high specificity (rules-IN bacteremia), except interestingly “shaking chills”. Notice almost all the criteria listed below approach a likelihood ratio (LR) of 1.0. Two prediction rules do exist, however, to help you virtually rule-OUT bacteremia:
- SIRS
- Shapiro prediction rule
The list of LRs also will be helpful to show learners in the ED that an isolated serum WBC number is useless risk-stratifier.
Patient Case
A 55 y/o man with a PMH of hypertension presents with a community-acquired pneumonia on CXR, no fevers, no chills, no vomiting.
- Temperature 37.8 C, BP 160/90, HR 100, RR 16, Sat 100% RA
- Serum WBC 20K (no bands)
- Platelets 300K
- Creatinine 1.1 mg/dL
What is the patient’s pre-test and post-test probability for having bacteremia? Use these helpful stats from the Rational Clinical Examination series from JAMA.
PV Card: Blood Cultures for Suspected Bacteremia
Adapted from [1]
Go to ALiEM (PV) Cards for more resources.
Answer to patient case
- Start with 7% pretest probability for bacteremia with a community acquired pneumonia.
- Using the clinical prediction rules, the WBC 20K and HR 100 bpm are criteria for SIRS but do not fulfill the Shapiro prediction criteria. LR = 1.8 * 0.08 = 0.144. Post-test probability for bacteremia = 0.06%.
- If the patient had instead a normal HR of 80 bpm, both the SIRS and Shapiro criteria would have been negative. LR = 0.09 * 0.08 = 0.0072. Post-test probability for bacteremia = << 0.1%.
This discussion doesn’t address WHETHER we should get blood cultures despite a risk for bacteremia in the setting of uncomplicated pneumonia receiving IV antibiotics or pyelonephritis with a pending urine culture.
References
- Coburn B, Morris A, Tomlinson G, Detsky A. Does this adult patient with suspected bacteremia require blood cultures? JAMA. 2012;308(5):502-511. [PubMed]
- Shapiro N, Wolfe R, Wright S, Moore R, Bates D. Who needs a blood culture? A prospectively derived and validated prediction rule. J Emerg Med. 2008;35(3):255-264. [PubMed]
Paucis Verbis: Overanticoagulation and supratherapeutic INR
I find it amazing that I know more non-emergency physicians virtually in the social media world rather than in person. Primarily through Twitter, I follow and am followed by medical educators from various specialties. If you haven’t joined Twitter yet, I think it might be time. There is a whole world of collaboration and conversation going on in this virtual community, which crosses specialties and geography.
Last week, Dr. Javier Benítez (@jvrbntz) was tweeting a Question of the Day, referencing a 2010 Paucis Verbis card on overanticoagulation, which was based on the 2008 American College of Chest Physicians (ACCP) guidelines. About 8 minutes after I retweeted his question, Dr. Roy Arnold (@cholerajoe), a pulmonary/critical care physician kindly informed me that the 2012 ACCP guidelines have been out since February.
So this PV card is replacing the 2010 card with revised recommendations. For more in-depth discussion, definitely take a look at Dr. Scott Weingart’s great podcast over at EMCrit. He helps to clarify holes which the 2012 ACCP guidelines don’t really address such as:
What if the patient is minorly bleeding with a high INR?
- Oral vitamin K and 15 mL/kg FFP
What if you only have the 3-factor PCC (factors II, IX, X) and not the recommended 4-factor PCC (factors II, IX, X plus factor VII)?
- If PCC is indicated, add recombinant factor VIIa or FFP to the 3-factor PCC to cover for factor VII.
PV Card: Overanticoagulation and Supratherapeutic INR
Adapted from [1]
Go to ALiEM (PV) Cards for more resources.
Reference
- Holbrook A, Schulman S, Witt D, et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e152S-84S. [PubMed]
Mythbuster: The 10% cephalosporin-penicillin cross-reactivity risk
To give or not to give a cephalosporin in penicillin-allergic patients?
I remember back to my days in pharmacy school when I learned that there was approximately a 10% risk of cross-reactivity, if a cephalosporin was given to a penicillin-allergic patient. They probably said something about the risk being less with 3rd and 4th generations cephalosporins, but lets be honest… who remembers anything but that magic 10%? When I started working more with physicians, I found that they also learned the same 10% rule in medical school. Well, I guess that means it’s fact, right? Not so fast!