Q: What is the formula to convert S/F ratio to P/F ratio? 

 - PaO2/FiO2 and SpO2/FiO2 ratio 


Answer: S/F = 64 + 0.84*(P/F) 

 An S/F value of 235 corresponded with P/F ratio of 200 while S/F value of 315 corresponded with P/F ratio of 300. Study shows that validation database from 2031 measurements produced a linear relationship.

Ultrasound Guidance for Thoracentesis

Parker Nasal Intubation

 

Q: 34 year old male patient had LP (lumbar punture) 4 days ago but continue to complaint of severe headache. Analgesics are not working. What would be other simple recommendation?



Answer: Caffeine - 300-500 mg q4-6h


In severe cases Caffeine sodium benzoate (500 mg) in 1 liter of fluid (D5LR) can be given intravenously over one and a half hour. The patients usually have complete resolution of symptoms and no recurrence of headache.

Caffeine sodium benzoate is a simple treatment of post-lumbar-puncture headaches. It should be considered as a safe alternative to an epidural blood patch for the treatment of post-lumbar-puncture headaches.


A simple treatment of post-lumbar-puncture headache. - J Emerg Med. 1989 Jan-Feb;7(1):29-31.

Sympathetic Storming
Sympathetic storming after traumatic brain injury remains one of the most dramatic clinical scene particularly in neurological units. It occurs due to uncontrolled sympathetic surge with a diminish or unmatch parasympathetic response. Acording to Baguley criteria 5 out of the 7 clinical features should be present - tachycardia, tachypnea, hyperthermia, hypertension, dystonia, posturing, and diaphoresis. Various agents have been used for treatment (see review article below) but haloperidol may worsen the symptoms.

Dr. Blackman and coll. coined the term "PAID" - paroxysmal autonomic instability with dystonia- in Archives of Neurology March 2004.
References: click to get abstract/article

1. Dysautonomia after traumatic brain injury: a forgotten syndrome? - J Neurol Neurosurg Psychiatry 1999;67:39-43 ( July )
2. Paroxysmal autonomic instability with dystonia (PAID) - Arch Neurol. October 2004;61:1625.
3. Paroxysmal Autonomic Instability with Dystonia After Brain Injury - Arch. Neurol. March 2004;61:321-328
4. Riding Out the Storm: Sympathetic Storming After Traumatic Brain Injury - Denise M. Lemke, MSN CS-RN ANP CNRN - J Neurosci Nurs 36(1):4-9, 2004.

A note on Factor 7 (rVIIa) and thrombocytopenia

Factor 7 (rVIIa - Novoseven) is now significantly use as off label in uncontrolled bleeding. It may not be efective in the presence of severe thrombocytopenia and should be corrected prior to its administration.

Although there are case reports of the successful use of rVIIa in severe thrombocytopenia, a low platelet count is likely to predict a poor or partial response to rVIIa therapy. Its haemostatic effects are mediated by the thrombin it generates by both tissue factor (TF) dependent and independent mechanisms. The TF independent mechanism requires platelets for the direct activation of Factor X on their surface by rVIIa.

Red urine during transfusion.
Q; You have been called to evaluate a patient who developed red-urine. At bedside, you noticed pRBC transufion in progress. What would be your first few immediate responses?


A; The first thing you need to determine is whether it is a transfusion reaction (hemolysis) or a pure hematuria. Send Urine or blood for centrifuge.

The onset of red urine during or shortly after a blood transfusion may represent hemoglobinuria from acute hemolytic reaction. To distinguish it from hematuria, if freshly collected urine is centrifuged, the urine sample remains clear red. If its pure hematuria, red blood cells settle at the bottom of the tube, leaving a clear yellow urine supernatant. Similarly patient's blood with centrifuge will turn free serum as a pink color from free hemoglobin in a clotted centrifuged specimen otherwise serum will be yellow if no transfusion reaction.

Other steps to take.

1. Halt the transfusion.

2. Send donor blood and patient's blood quickly to blood bank to make sure that right blood was transfused (repeat crossmatch and type) and for antibody screen, and direct and indirect Coombs tests.

If transfusion reaction is highly suspected:

3. Administer IV Benadryl, IV steroid, IV saline followed with IV lasix or with low dose dopamine to improve renal blood flow. Symptomatic treatment with acetaminophen.

4. Airway protection and if seems to be anaphylactic reaction, administer epinephrine (nebulizer treatment, SQ or IV drip depending on severity). Oxygen to keep saturation up.

5. Send complete lab workup including lytes, renal function (BUN/Cr), serum bilirubin level (peaks in 3-6 hours), Haptoglobin (binds to hemoglobin) , urine for hemoglobinuria, a repeat CBC (fails to show the rise in hematocrit because of intravascular or extravascular hemolysis) and DIC panel.

6. Hematology consult.
Management is largely supportive.

Q: 32 year old otherwise healthy male with 2 weeks history of sinusitis presented with siezure. ER physician called you while he sent patient to CT scan. What would be your primary concern and line of action? 


 Answer: Neurological symptoms after prolong bout of sinusitis is highly suggestive of Subdural empyema.

 Subdural empyema is a neurosurgical emergency and beside instituting antibiotics and anti-seizure meds, it would be appropriate to ask neurosurgical service to review CT scan while patient is in neuroradiology department. It has a tendency to spread rapidly through the subdural space.

Q: What could be the supporting finding on lab in (Transfusion-related acute lung injury (TRALI)? 

 Answer: Laboratory findings may include unexpected haemoconcentration and a sudden fall in serum albumin.

Q: Name an epileptic drug which can be given rectally if required?


 Answer: Depakote (valproic acid) Dilute syrup 1:1 with water for use as a retention enema; loading dose: 17-20 mg/kg one time; maintenance: 10-15 mg/kg/dose every 8 hours

Q: Which of the following medicines can cause "Red Man Syndrome"? 

 A) Ciprofloxacin, 
 B) Amphotericin B, 
 C) Rifampcin 
 D) Vancomycin 
 E) All of the above 

 Answer: All of the above Antibiotics such as ciprofloxacin, amphotericin B and rifampcin can also potentially cause red man syndrome beside vancomycin. Like vancomycin, they are capable of causing direct degranulation of mast cells and basophils. Red man syndrome is amplified if these antibiotics are combined with vancomycin or with each other. Red man syndrome is also magnified in patients receiving vancomycin and opioid analgesics, muscle relaxants, or contrast dye because these drugs can also stimulate histamine release.

Ice test - Poor man's test for Myasthenia Gravia 

 Most of the Myasthenia patients along with other symptoms of weakness usually exhibits ptosis. While at bedside place an ice cube over eye lids for 2 minutes. Cooling improves neuromuscular transmission. Resolution of ptosis with cooling is a positive test for Myasthenia Gravis and reported upto 80% reliable to diagnose ocular myasthenia.

Q: What is the best way to follow on Amiodarone overdose? 

 Answer: Follow serial QT duration 

 Surprisingly, Overdose with amiodarone is usually benign as it is very poorly and variably absorbed. But all such patients should be admitted to ICU/CCU for close observation and serial EKGs. On EKG, Amiodarone leads to a prolonged QT interval due to its blocking of repolarising of. potassium channel. The QT duration is the best indicator of the extent of potassium channel blockade.

Q: 42 year male with no previous history known is brought to ER with mental status change, fever and nuchal rigidity. CT scan is not much of information. ER doc performed lumbar punture and transferred patient to ICU. You get STAT call from lab that there is a spiderweb clot in the collected CSF. What does it mean?


Answer: A spiderweb clot in the collected CSF is characteristic of TB meningitis though not always present. 

The CSF usually has a high protein, low glucose and a increase lymphocytes. Acid-fast bacilli commonly grown in culture but the culture of TB from CSF takes about two weeks, and therefore the majority of patients with TB meningitis are started on treatment before the diagnosis is confirmed.

A note on balloon inflation volume of Pulmonary Artery catheter in patients with Pulmonary Hypertension

Pulmonary artery occlusion pressure (PAOP) - commonly know as wedge - is used to differentiate patients having pulmonary hypertension (PH) due to left-sided heart disease from other etiologies. 

One interesting study published in 2010 (see reference), investigated the PAOP measurements obtained from both pulmonary arteries with balloon full (1.5 mL) and half (0.75 mL) inflation in patients with suspected PH.

Study showed that PAOP can be falsely elevated in patients with PH according to the balloon inflation volume. Balloon half inflation was safe and correlated with higher precision and lower bias in the PAOP measurements.

Effect of Balloon Inflation Volume on Pulmonary Artery Occlusion Pressure in Patients With and Without Pulmonary Hypertension - CHEST January 2011 vol. 139 no. 1 115-121

A note on SVo2 and ScVo2

ScvO2 reflects principally the degree of oxygen extraction from the brain and the upper part of the body.

SvO2 reflects the relationship between whole-body O2 consumption and cardiac output.

Pitfall of ScVo2: The central venous catheter usually resides in the superior vena cava. Thus central venous blood sampling reflects the venous blood of the upper body but neglects venous blood from the lower body (i.e., intra-abdominal organs).  ScvO2 is usually less than SvO2 by about 2–3% because the lower body extracts less O2 than the upper body making inferior vena caval O2 saturation higher.

SvO2 and ScvO2 changes in parallel when the whole body ratio of O2 supply to demand is altered.

Q: How much time does oral Vitamin K take to be effective?


Answer: About 24 hours

In absence of active bleeding, oral Vitamin K is always preferable. Only disadvantage is its slow action. IV vitamin K takes about 6 to 12 hours to achieve expected INR and oral Vitamin requires about 24 hours.

Though IV vitamin is faster than oral Vitamin K, it carries the chances of anaphylactoid reaction even with minor dose. Also less known side effect of IV Vitamin K is over-correction of anticoagulation.

Comparison of Oral vs Intravenous Phytonadione (Vitamin K1) in Patients With Excessive Anticoagulation - A Prospective Randomized Controlled Study : Arch Intern Med. 2003;163(20):2469-2473.

Anaphylaxis after low dose intravenous vitamin K - J Emerg Med. 2003 Feb;24(2):169-72.

2 Phases of Amniotic Fluid Embolism (AFE)

Once the fluid and fetal cells enter the maternal pulmonary circulation, usually AFE presents as 2 phases.

First phase: The patient experiences acute shortness of breath which may lead to hypotension and cardiac arrest. It is said that half of women does not survive beyond this phase.

Second phase: Survivors of first phase will pass onto the second phase. This is known as the hemorrhagic phase and may be accompanied by severe shivering, coughing, vomiting, and the sensation of a bad taste in the mouth. This is accompanied by excessive bleeding due to DIC.

Treatment is mostly supportive.

Following is the protocol for Argatroban for patients effected with HIT (Heparin-induced thrombocytopenia)

Click here

Source:  Bon Secours Health System

Q: Why Heparin is called Heparin? 

 Answer: Heparin was discovered by a second-year medical student at Johns Hopkins University named Jay McLean, in 1916, when he isolated a fat-soluble phosphatide anti-coagulant in canine liver tissue. 'Hepar' is Greek for "liver", hence it was termed as Heparin.

Q: The Activated Clotting Time (ACT) is essentially a point of care test (POC) of coagulation that is used to monitor the anticoagulant effect of unfractionated heparin. (PTT is a 'send down' lab test). What is the ACT value in a non-anticoagulated patient? 


 Answer: In a non-anticoagulated patient, the ACT is in the region of 110s. During cardiopulmonary bypass, heparin is titrated to maintain an ACT between 400 to 600s. During ECMO, recommended value is between 200 and 240s

TandemHeart Training Video

Q: What are the classic findings in Ventricular Aneurysm repair?

Answer:Classic findings in Ventricular Aneurysm are

• first degree AV block
• left ventricular hypertrophy (LVH)
• right branch bundle block (RBBB)
• Q waves V1-V5, I, aVL with persistent ST elevations in these leads

View an EKG here: http://www.emergency-medicine-tutorials.org/Home/medical-3/cardiovascular/ecgs-1/ventricular-aneurysm

IVC filter migration to heart 

 Source: Inferior Vena Cava Filter Migration to the Right Ventricle: A Case Report and Review of Filter Migration and Misdeployment - Volume 2, Number 5, October 2011, pages 201-205 

weblink to source: http://www.journalmc.org/index.php/JMC/article/viewArticle/240/194

Figure. Lateral chest radiograph showing the location of the IVC filter in the heart (arrow).

A note on False positive Troponin I due to RF

Troponin complex is located on the thin filament of skeletal and myocardial muscle. The high sensitivity and specificity of cardiac troponin to detect myocardial injury is well documented. However, various factors can interfere with the TnI assay, leading to falsely elevated levels. This include particularly rheumatoid factor (RF).

Rheumatoid factor causes interference in the immunoassays. 5% of healthy people may have circulating rheumatoid factor, and approximately 1% of patients with elevated cardiac TnI levels may have this elevation solely because of the rheumatoid factor.


References:

1. Schifman, RB, James, SH, Sadrzadeh, SMH, et al Between-assay variation in false positive troponin I measurements in patients on renal dialysis or with positive rheumatoid factor - Clin Chem 1999;45,A145

2. Krahn, J, Parry, DM, Leroux, M, et al High percentage of false positive cardiac troponin I results in patients with rheumatoid factor. Clin Biochem 1999;32,477-480

Q: 48 year old male after crushing injury developed Rhabdomyolysis. At what day you expect CPK to peak?

Answer: Despite adequate treatment, CPK usually peaks on day 3 and decrease by half every 24-48 hours. It is clinically important to continue management.

Q: What added advantages Metformin offer in diabetic patients with cardiac morbidity? 

 Answer: Metformin is shown to reduce LDL and triglyceride levels. Moreover, unlike other anti-diabetics it is not associated with weight gain and is pretty safe in CHF patients.

Q: Mesothelioma can occur in which other organ beside pleura, pericardium and peritoneum? 


Answer: Testicles (Tunica Vaginalis layering)

Malignant mesothelioma is a tumor which arises in body cavities lined by mesothelium. Mostly these tumors are detected in the pleura, peritoneum and pericardium. As the tunica vaginalis is a layer of reflected peritoneum, mesothelioma can occur in the scrotal sac. The nonspecific symptoms and lack of tumor markers make diagnosis of malignant mesothelioma of the tunica vaginalis very difficult.

Peds critical care

 Q: Which diuretic carries anti epileptic property particularly in neonates? 

 Answer: Bumex 

 Bumetanide (Bumex) is a loop diuretic. In the brain, bumetanide blocks the NKCC1 cation-chloride co-transporter, and thus decreases internal chloride concentration in neurons. In turn, this concentration change makes the action of GABA more hyperpolarizing, which may be useful for treatment of neonatal seizures, that quite often are not responsive to traditional GABA-targeted treatment, such as barbiturates. Bumetanide is currently under evaluation as a prospective antiepileptic drug. 


http://clinicaltrials.gov/ct2/show/NCT00830531

Q: In nephrogenic diabetes insipidus (DI), thiazide diuretics are frequently used, which despite a diuretic causes an overall fluid conservation. But it may frequently lead to hypokalemia. Addition of which other diuretic may help? 


Answer: Amiloride 

 Desmopressin does not work in nephrogenic DI. A thiazide diuretic or indomethacin may improve nephrogenic diabetes insipidus. Thiazide diuretics are sometimes combined with amiloride to prevent hypokalemia. Amiloride has potassium-sparing capacities which often actually results in mild hyperkalemia.

Mnemonic of hypercalcaemia 

•  Stones (kidney or gallstones) 
•  Bones (bone pain) 
•  Groans (Gi pain and symptoms) 
•  Thrones (sit on throne - polyuria) 
•  Psychiatric overtones (Depression, anxiet, cognitive dysfunction, insomnia, coma)

Q: Although Vancomycin remained the treatment of choice for MRSA Pneumonia due to its high cost effectiveness, but what advantage does Zyvox (Linezolid) has over Vancomycin in lung related infections?


Answer: Linezolid is better than vancomycin against nosocomial pneumonia, like MRSA ventilator-associated pneumonia because the penetration of linezolid into bronchial fluids is much higher than that of vancomycin.

Other minor advatanges include high bioavailability, easy switching to oral therapy and no required adjustments in renal failure.