Tuesday December 8, 2009
Life-threatening sodium valproate overdose: A comparison of two approaches to treatment

Objectives: To describe two identical cases of severe sodium valproate overdose treated with two different approaches.

Design: Case report and review of the literature.

Patients: Two cases of identical life-threatening valproate (VPA) overdose with high VPA blood levels, markedly elevated ammonia levels and coma.

Interventions:

• One patient was treated with supportive therapy alone until the development of cerebral edema and seizures;
• the other was treated with immediate extended hemodialysis followed by high-volume hemodiafiltration.

Measurements and Main Results: The first patient remained critically ill with elevated VPA and ammonia levels until the development of seizures and life-threatening cerebral edema. After the delayed application of hemofiltration, the patient slowly recovered to be discharged from intensive care on day 11. In contrast, the second patient's VPA and ammonia levels rapidly declined with hemodialysis and hemodiafiltration with rapid clinical improvement and intensive care discharge on day 3.

Conclusions: In severe VPA overdose, early intervention with blood purification of suitable intensity was associated with a rapid reduction in VPA and ammonia levels and clinical improvement. This improvement was not seen with supportive therapy alone.


Life-threatening sodium valproate overdose: A comparison of two approaches to treatment - Critical Care Medicine: December 2009 - Volume 37 - Issue 12 - pp 3161-3164

Monday December 7, 2009

Q: What percentage of patients may experience post extubation stridor (PES)?

Answer: About 15%

A low cuff-leak volume (less than 130 ml or 12%) around the endotracheal tube prior to extubation is useful in identifying patients at risk for post-extubation stridor.

Racemic Epinephrine, Heliox and and Decadron has been used as treatment for PES. It may require re-intubation in severe cases.

Sunday December 6, 2009


Q: 54 year old asian male presented to ED with cough and left sided chest pain. CXR showed pleural effusion. Radiologist call you with the result adding "there is relative enlargement of the left sided ribs". What does it imply?


Answer: Chronic pleural effusion

The most common cause is tuberculosis and require close workup and possible isolation. Changes in the ribs of patients with tuberculosis as well as the other patients with chronic effusion are due to local hyperemia from an adjacent inflammatory process. In advanced cases, the affected side of the thorax is also contracted, so gravitational and postural factors might also play a role.

Remember these rib changes are not case of direct or metastisize skeletal tuberculosis as there is no destruction of bone.



Reference: Click to get article

Rib Enlargement in Patients with Chronic Pleural Disease - AJR:167, October 1996

Saturday December 5, 2009


Q: What is Haldane effect?

Answer: The Haldane effect (named after John Scott Haldane) describe that deoxygenation of the blood increases its ability to carry carbon dioxide. Conversely, oxygenated blood has a reduced capacity for carbon dioxide.

The Haldane effect promotes dissociation of carbon dioxide from hemoglobin in the presence of oxygen. In the oxygen-rich capillaries of the lung, this property causes the displacement of carbon dioxide to plasma as venous blood enters the alveolus and is vital for alveolar gas exchange.

This partially explains the observation that some patients with emphysema might have an increase in PaCO2 following administration of supplemental oxygen even if content of CO2 stays equal.

Oxygenation of Hb promotes dissociation of H+ from Hb, which shifts the bicarbonate buffer equilibrium towards CO2 formation; therefore, CO2 is released from RBCs.

Friday December 4, 2009
Pulmonary Artery Catheter in Amniotic fluid embolism !!

20 years ago it was suggested by Mason that probable diagnosis of Amniotic fluid embolism can be made by analyzing pulmonary artery blood with the logic that amniotic fluid does not ordinarily enter the maternal circulation, and the identification of large numbers of fetal squamous in the postpartum pulmonary microvasculature is of clinical significance. (He applied similar argument for other similar diseases such as fat embolism). Diagnosis becomes more probable if other fetal debris such as mucin or hair is present.

Technique described: Obtain blood from the distal lumen of a pulmonary artery catheter (in wedged position). After discarding the first 10 ml of blood, draw an additional 10 ml, heparinize and analyze utilizing Papanicolaou's method.Above technique is only suggestive of amniotic fluid embolism and not a gold standard.


Power Point Presentation: AMNIOTIC FLUID EMBOLISM



References: Click to get abstract/article

1. Pulmonary microvascular cytology. A new diagnostic application of the pulmonary artery catheter - Chest, V. 88, 908-14

2. Amniotic fluid embolism - Masson RG - Clin Chest Med.1992 Dec;13(4):657-65.

Thursday December 3, 2009


Q: What is Scombroidosis?


Answer: Scombroidosis refers to histamine poisoning from the ingestion of fish improperly stored at an elevated temperature. Histamine and cis-urocanic acid are produced by various bacteria that multiply in the spoiled fish.

Patients usually present with a frightening flush but no urticaria, palpitations, syncope, nausea, vomiting, or diarrhea.

Wdneesday December 2, 2009
Bedside trick


Q: How to make IABP more visible radiographically (on CXR) after insertion?


Answer: Shoot CXR on standby mode.

As in stand by mode there is no movement of baloon, chances to have better capture of IABP tip is high.