Patwari Academy videos: Toxicology
What is your approach to the poisoned patient? Listen to these 4 videos by Dr. Rahul Patwari to build your foundation of knowledge in toxicology.
- Introduction
- Toxidromes
- Testing
- Decontamination
PV card: VBG versus ABG
You obtain a venous blood gas (VBG) on a patient with a COPD exacerbation because you are concerned about hypercarbia. You get a value of 55 mmHg. How correlative is that compared to an arterial blood gas (ABG). There has been a lot of literature on how well the pH correlates between the ABG and VBG but what about pCO2?
A small study (n=89) from 20121 found that with a cutoff of pCO2 < 45 mmHg, the venous pCO2 is 100% sensitive in ruling out arterial hypercarbia. When the pCO2 was ≥ 45 mmHg, the VBG was less correlative.
Below is a review by Dr. Michelle Reina (EM resident at Univ of Utah) and Dr. Rob Bryant (Intermountain Medical Center in Utah) of the VBG vs ABG correlative data, along with a proposed algorithm on what to do with patients with COPD exacerbation.
What is your practice with an elevated pCO2 value on VBG?
Adapted from [1–5]
Go to ALiEM (PV) Cards for more resources.
Updated 1/31/13 at 2 pm PST:
- Changed range of pH correlation between VBG and ABG = 0.03-0.04
- Was typo in abstract of Kelly et al article.2 Stated difference between pHs was 0.4, rather than 0.04 as described in main results text.
References
- McCanny P, Bennett K, Staunton P, McMahon G. Venous vs arterial blood gases in the assessment of patients presenting with an exacerbation of chronic obstructive pulmonary disease. Am J Emerg Med. 2012;30(6):896-900. [PubMed]
- Kelly A, McAlpine R, Kyle E. Venous pH can safely replace arterial pH in the initial evaluation of patients in the emergency department. Emerg Med J. 2001;18(5):340-342. [PubMed]
- Ma O, Rush M, Godfrey M, Gaddis G. Arterial blood gas results rarely influence emergency physician management of patients with suspected diabetic ketoacidosis. Acad Emerg Med. 2003;10(8):836-841. [PubMed]
- Middleton P, Kelly A, Brown J, Robertson M. Agreement between arterial and central venous values for pH, bicarbonate, base excess, and lactate. Emerg Med J. 2006;23(8):622-624. [PubMed]
- Koul P, Khan U, Wani A, et al. Comparison and agreement between venous and arterial gas analysis in cardiopulmonary patients in Kashmir valley of the Indian subcontinent. Ann Thorac Med. 2011;6(1):33-37. [PubMed]
Patwari Academy videos: Demystifiying how ECGs work
As a nice segue from the Low Risk Chest Pain videos, below is a 3-part series on Demystifying the Electrocardiogram by Dr. Rahul Patwari. It takes talent to make the complex simple.
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App review: POC Ultrasound Guide
There is a new free app called POC Ultrasound Guide [iTunes link], created by Wexner Medical Center at Ohio State University.
PV card: Diagnosis of DVT (ACCP guidelines)
A patient presents with an asymmetric leg with trace pitting edema in the affected leg. What is your diagnostic approach to such a patient? What is the role of D-dimer and ultrasound (U/S)? Does this match the 2012 American College of Chest Physicians (ACCP) guidelines?
The first step is to determine your patient’s pretest probability because the recommendations vary based on risk. I can tell you that many ED patients come in with a Wells score of 1-2, which places them in the “moderate pretest probability” category. There are 2 approaches you can take based on the availability of resources at your site (high-sensitivity D-dimer or U/S) and the patient’s comorbidities. Are you referring your patient for a repeat outpatient ultrasound, if warranted?Walk through various patient scenarios to see how the D-Dimer and U/S come into play.
PV Card: Diagnosting DVT – ACCP Evidence Based Guidelines
Adapted from [1]
Go to ALiEM (PV) Cards for more resources.
Thanks to Dr. Jason West (EM resident at Jacobi/Montefiore) for this card idea and deciphering the complex recommendations from the publication.
Reference
- Bates S, Jaeschke R, Stevens S, et al. Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e351S-418S. [PubMed]
One-dose vancomycin for SSTIs: Just don’t do it
You are managing an otherwise healthy patient with cellulitis but no abscess to poke. You decide this patient needs antibiotics but is stable enough to go home.
“Give em’ a dose of vanc before they go,” right?
Trick of Trade: Incision and loop drainage using tourniquet
The technique for abscess drainage traditionally is incision and drainage (I&D). In August 2012, I wrote about incision and loop drainage (I&LD), which it seems has gained popularity over time with similar outcomes. This technique involves using a sterile vascular loop, which is thin and long enough to form a loose knotted loop. The video below by Dr. Rob Orman reviews the steps. But, what if you don’t have a vascular loop in the ED?