Pulmonary Embolism Fast Facts: Wells Score Menmonic

Clots can form due to many reasons that we all are aware about. Let's do a quick review of certain facts for this deadly diagnosis.

• Pulmonary Emboli arise from Proximal DVT (Above the Knee)
• Distal DVTs in itself does not a risk for PE unless they migrate upwards.
• Pregnancy PEs are from Pelvic Veins (Risks last upto 2 months post delivery)
• PE = Alveolar Dead Space Ventilation
• ~ 50% Lung involved will lead to Pulmonary HTN
• Massive PE =  >70% Lung Involvement (10% will die in first 1 Hour)
• Recent Surgery in last 4 weeks poses a risk (mostly it is Orthopedic Surgery: 70% Risks in Knee Surgery)
• Unexplained DVT: 15 - 20 % of these will develop malignancy in next 2 years 

Do I need an Arterial Blood Gas (ABG)?

Is Venous Blood Gas (VBG) as good as an Arterial Blood Gas (ABG)?

In the emergency settings, we often seek a quick answer to patient’s milieu through blood gas parameters. Most ED physicians draw up the venous blood gas sample to look for the metabolic parameters and the electrolyte status of patients. However, in certain specialties and different settings, the usage of a VBG as equal to that of an ABG sample has been often disapproved.

Although an ABG sample serves as a gold standard to determine the pH, PaCO2, HCO3, lactates, and the PaO2 accurately, it, at times, gives poor indication of the electrolyte status. In addition, it comes with additional pain and risk of injury to the vessel (pseudo aneurysms, hematoma and AV fistula) and surrounding structures (nerve injury). Serial exams will need additional pricks, and also carries a risk of digital ischemia. Moreover, additional work may seem an additional delay in care too.

On the other hand, venous blood sampling is usually easier, less painful and more convenient. VBG gives you a rapid and good assessment of the pH, HCO3, and the base excess. As long as the patient is normocapnic, it gives a good estimate of the PaCO2. In cases where the pulse oximetry is reliable and the patient does not appear to be in shock state, the SpO2 is sufficient for clinical decision making. Additionally, it gives a quick estimate of the electrolytes too.

Take Home Points:

•  If you are concerned about the pH: The Venous pH has a good correlation with the arterial pH within 0.03 – 0.04 units
•  The HCO3 and the base excess has good correlation
•  Venous lactate has a good correlation with the arterial lactates unless < 2mmol/L
• If you are concerned about hypercarbia: VBG serves to be 100% sensitive in detecting hypercarbia with a cut off of PCO2 of 45 mm Hg. A venous PCO2 of more than 45 means you are hypercarbic. If you need to know the accurate CO2 levels then get an ABG
• The Venous lactate and the PCO2 may not correlate in shock states
•  Want to know the PaO2 or to calculate the A – a gradient, get an ABG

Further Readings:

Kelly, A. (2010). Review article: Can venous blood gas analysis replace arterial in emergency medical care. Emergency Medicine Australasia 22, p493–498.

 McCanny, P., Bennett, K., Staunton, P., McMahon, G. (2012).Venous vs arterial blood gases in the assessment of patients presenting with an exacerbation of chronic obstructive pulmonary disease. Am J Emerg Med. 30(6): p896-900.

Middleton P, Kelly AM, Brown J, Robertson M. (2006). Agreement between arterial and central venous values for pH, bicarbonate, base excess, and lactate. Emerg Med J. 23(8): p622-4.

Succinyl Choline (Suxamethonium)

A great drug of choice for paralysis in RSI, but carries it's own list of side-effects and C/I.

Dose: 1.5 mg/kg IV

Side Efects (BAHAMAS)

Bronchospasm
Anaphylaxis
Hyperkalemia
Arrythmias (Brady and Tachy)
Malignant Hyperthermia
Apnea (especially in inadequate pseudo-cholinesterase)
Secretions (Salivation)

Contraindications (CNBC Eye)

Crush Injuries
Neurological: Spinal Cord Injury, Myotonic dystrophy
Burns
Chronic Renal Failure
Eye (Penetrating injury of the eye)

(To know more about Anesthesiology Visit www.gasexchange.com)

MCEM SAQ 2

A 3 year-old boy presents accompanied by his Dad. He suffers with asthma for which he takes a salbutamol inhaler as required. He has been coryzal for the past few days and has become wheezy this evening. His best peak flow is 250 L/min and his peak flow this evening is 180 L/min. His observations are as follows: HR 100, RR 26, SaO2 97% on air, Temperature 37.4°C.

How would you classify his asthma at this presentation? (1)
Outline your initial management in the ED: (3)
What are the normal ranges for heart rate and respiratory rate in a child this age? (2)
He responds to your initial treatment. Outline your discharge plan: (2)
List 4 features of acute severe asthma in this age group: (2)

Answers in British Thoracic Society (BTS) Guidelines for Asthma (need to know Adults and Paeds criteria for classification - e.g. life threatening, severe, moderate, mild

(Courtesy: Dr Shweta Gidwani, London (UK))

Pulmonary Embolism Mnemonic for Well Score

Don’t                          (DVT symptoms)                         3 points 
Die                             (Diagnosis most likely PE)            3 points 
Tell                            (Tachycardia)                             1.5 points 
The Team                  (Three days [at least] of immobilization, or surgery in the past Thirty days) 1.5 points 
To                             (Thromboembolism in the past [DVT or PE]) 1.5 points
Calculate                    (Coughing up blood [hemoptysis]) 1 point
Criteria                       (Cancer)                                    1 point

This is what the scores mean:
> 6 High probability of PE
2-6 Moderate probability of PE
< 2 Low probability of PE

(Courtesy: Dr. Ram NG, Mumbai)

SAQ 1

42 yr old lady presents to your ED.complaints of pleuritic left sided chest pain that started earlier that day.she has breathlessness on minimal exertion. She gives recent history of long flight journey and that her mother died bcos of blood clot in the lungs .she also complaints of right leg swelling. Vitals pr of 113 and rr of 30 ,spo2 97%, bp of 114/72.physical exam reveals a tender right leg swelling.

1. Important dd is pe. What is the most useful initial investigation in this pt and y??

2. What r the possible ecg changes that one can expect?

3. Her blood gas shows ph 7.38,paco2 -3kpa ,pao2 -10kpa ,hco3 - 28 mmol/l, she s breathing 60% O2 via venturi mask, Whats her A-a gradient?

4. Whats her wells score ??

(Place your answers in Comments Section)
(Question Courtesy: Dr Ram NG, Mumbai)

If you have made any questions and/or notes and would like to share it on the blog, please email them at drsajjadpathan@gmail.com.

BTS Guidelines for Management of Pneumothorax

Full Article: BMJ

(Source: http://www.brit-thoracic.org.uk/Portals/0/Guidelines/PleuralDiseaseGuidelines/Pleural%20Guideline%202010/Pleural%20disease%202010%20pneumothorax.pdf)

CURB 65 Pneumonia Risk

CURB-65 Severity Score for Community-Acquired Pneumonia

(Calculates the CURB-65 Score to estimate pneumonia mortality to help determine inpatient vs. outpatient treatment)

Confusion                                                                                          1

BUN ­> 19 mg/dL                                                                             1

Respiratory rate > 30/minute                                                        1

Systolic Blood Pressure < 90 mm Hg or                                      1

Diastolic Blood Pressure < 60 mm Hg

Age > 65 Years                                                                                 1

Total Score

Risk Score	30 Day Mortality %	Recommendations
1 (Low Risk)	2.7 %	Consider Outpatient Treatment
2 (Moderate Risk)	6.8%	Consider Inpatient treatment or Outpatient Treatment with close follow up
3 (High Risk)	14%	Consider Inpatient treatment with possible intensive care admission
4 – 5 (Highest Risk)	27.8%	Consider Inpatient treatment with intensive care admission

Case Study 1: Respiratory Emergencies

35 yr old lady is admitted to the ED with complaints of SOB and cough for last 3 days. She is being treated with oral antibiotics for pneumonia by her GP. She suddenly develops respiratory distress and desaturates. The ED resident decides to intubate and mechanically ventilate the patient. Post intubation, air entry is found to be equal, and her saturations now are 95+ on FiO2 of 80. An XRC done as a protocol for post intubation is shown in the figure. What action must be taken at this moment?

a) Inform Respiratory Physician & Admit in ICU

b) Inform Respiratory Physician & Admit in Ward

c) Give injectable antibiotics

d) Reposition the tube

e) Increase FiO2 to 90 or 100 %, reduce TV, Give PEEP

f) Reduce TV, Give PEEP

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