Monday December 15, 2008

Q: Whats the danger of being very close to inguinal ligament while putting femoral venous or arterial central line?


Answer: Possible development of retroperitoneal hematoma and decrease ability to compress the bleeding site. Retroperitoneal hematoma is a serious and potentially very fatal complication after femoral cannulation. High femoral puncture (particularly if accompanied by coagulopathy), increases the risk of hematoma formation. Its always wise to stay well below inguinal ligament (atleast 3-4 cm) so developing hematoma is visible and can be compressed.

Sunday December 14, 2008


Case: While floating pulmonary artery catheter you have hard time measuring "wedge" (pulmonary artery occlusion pressure). After few attempts you noticed couple of blood drops in pulmonary artery catheter syringe. What does it mean and what should be you next step?


Answer: Pulmonary artery catheter balloon is rupture

When pulmonary artery catheter balloon is rupture, there could be two scenarios, either there is usually no resistance to balloon inflation or you may notice blood in the balloon port's tubing (syringe).

If there is suspicion of ballon rupture or blood in the balloon tubing,

• IMMEDIATELY clamp off the port
• Do not perform any PAOP/wedge measurement anymore
• Lock the port, and
• Tape over the port/syringe with a note "Balloon Busted"

Attempt to inject further air or to clear the blood may cause a potentially life-threatening air or blood clot emboli.

Saturday December 13, 2008
ECMO life-support proved more efficient than conventional CPR

Extracorporeal life-support as an adjunct to cardiac resuscitation has shown encouraging outcomes in patients with cardiac arrest. However, there is little evidence about the benefit of the procedure compared with conventional cardiopulmonary resuscitation (CPR), especially when continued for more than 10 min. Study was aimed to assess whether extracorporeal CPR was better than conventional CPR for patients with in-hospital cardiac arrest of cardiac origin.

Methods: A 3-year prospective observational study on the use of extracorporeal life-support for patients aged 18—75 years with witnessed in-hospital cardiac arrest of cardiac origin undergoing CPR of more than 10 min compared with patients receiving conventional CPR. Of the 975 patients with in-hospital cardiac arrest events who underwent CPR for longer than 10 min, 113 were enrolled in the conventional CPR group and 59 were enrolled in the extracorporeal CPR group.

The primary endpoint was survival to hospital discharge.

Results:

• Unmatched patients who underwent extracorporeal CPR had a higher survival rate to discharge and a better 1-year survival than those who received conventional CPR
• Between the propensity-score matched groups, there was still a significant difference in survival to discharge, 30-day survival and 1-year survival favouring extracorporeal CPR over conventional CPR.
• 82 percent of cardiac arrest patients who owed their survival to ECMO procedure returned to work within one year.

Conclusion: Extracorporeal CPR had a short-term and long-term survival benefit over conventional CPR in patients with in-hospital cardiac arrest of cardiac origin.


Reference: click to get abstract

Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with in-hospital cardiac arrest: an observational study and propensity analysis - The Lancet, Volume 372, Issue 9638, Pages 554 - 561, 16 August 2008

Friday December 12, 2008


Q: Following of which is the immediate drug of choice to treat ventricular tachycardia (V.Tach.) induced from Digitalis toxicity? - choose one

A) B- blocker
B) Calcium Channel Blocker
C) Amiodarone
D) Phenytoin
E) Quinidine


Answer: Phenytoin

Actually - Beta-blocker, Calcium Channel Blocker, Quindine and Amiodarone should be avoided in Digitalis induced ventricular tachyarrhythmias as they may exacerbate it.

In above situation either Phenytoin or Lidocaine should be the drug of treatment.

Thursday December 11, 2008


Q: Ibutilide is a type III antiarrhythmic agent approved for the pharmacologic conversion of atrial fibrillation and atrial flutter. Conversion rates is described upto 80% of cases. What is the half-life of Ibutalide?



A: 4 hours

Ibutilide (Corvert) is a Class III antiarrhythmic agent that is indicated for acute cardioconversion of atrial fibrillation and atrial flutter of a recent onset to sinus rhythm. Due to unknown reason, It show better results in atrial flutter as compared to atrial fibrillation.

Ibutalide should be use with caution as it may degenrate rhythm into sustained Torsade (polymorphic ventricular tachycardia) in 3% of cases. Also due to longer half life, its not recommended to repeat dose more than twice as it may take upto 90 minutes before normal sinus rhythm gets restored.

Dose is usually 1 mg over 10 minutes (may repeat once) but in post-cardiac surgery patients, one or two infusions of 0.5 mg is usually effective in terminating atrial fibrillation or atrial flutter.

Wednesday December 10, 2008
Regarding Low SVR state following off-pump CABG

Study was done to determine the prevalence, hemodynamic characteristics, and risk factors for low systemic vascular resistance (SVR) state following after off-pump coronary artery bypass (OPCAB).

PATIENTS AND METHODS: SVR data could be obtained for 116 OPCAB patients. Low SVR was defined as an indexed systemic vascular resistance (SVRi) of less than1,800 dyne x s/cm(5) x m(2) at the end of operation.

Hemodynamic data were recorded preoperatively, at the end of operation, just after entering ICU, and the following morning.

RESULTS: Low SVR state was noted in 54 of 116 patients (53%). The SVRi values in low-SVR and non-low-SVR patients were 1,406+/-253 and 2,326+/-509 dyne x s/cm(5) x m(2) at the end of operation.

• Increased CI level, decreased MAP level, but unchanged CVP level was observed postoperatively in the low-SVR patients. The increase in CI and decrease in MAP were maximal at the end of operation.
• Patients with low SVR were more likely to have a higher body mass index and to be male than no-low-SVR patients.
• In low-SVR patients, fluid balance was more positive intraoperatively but more negative at 6 hours postoperatively and 12 h postoperatively

CONCLUSIONS: Low SVR state, a probable manifestation of systemic inflammatory response (SIRS), is common in patients who have undergone OPCAB. For these patients it is more reasonable to maintain MAP with vasopressors by restoring vascular tone, than by volume loading.

Reference: click to get article

Ann Thorac Cardiovasc Surg. 2008 Feb;14(1):15-21

Tuesday December 9, 2008

Q: 52 year old male with history of End Stage Renal Disease (ESRD) - is admitted at 12 midnight with fluid overload, hypertensive crisis and mild hyperkalemia after he missed his dialysis session. Patient required intubation for hypoxemia but now saturating 100% on ventilator. Nephrology service informed you that it will take atleast 4 hours before hemodialysis can be arranged. Why Labetolol would be a bad choice for control of hypertension?

A: Labetolol may make hyperkalemia worse

Intravenous labetolol, a nonselective α- and β-blocking drug, is commonly used to treat severe hypertension but it can cause hyperkalemia. In patients with renal failure, it can be life-threatening, particularly in situations where emergent hemodialysis is not available.

Reference:

Life-Threatening Hyperkalemia after Intravenous Labetolol Injection for Hypertensive Emergency in a Hemodialysis Patient - Am J Nephrol 2001;21:241-244

Monday December 8, 2008


Q: 56 year old male is intubated in ICU with COPD exacerbation. In last one hour there are frequent "vent. alarms" but silenced by bedside staff. Patient now went into PEA (pulseless electrical activity). RT disconnected patient from ventilator but even before bagging is resumed, patient recovered good pulse and blood pressure?


A: Auto-PEEP induced PEA

Elevated end-expiratory pressure ("auto-PEEP") decreases venous return and may depress cardiac output. Transient withdrawal of ventilation allows the dynamic hyperinflation to be lessened, reducing intrathoracic pressure and permitting the return of spontaneous circulation. On the same token, it is important to avoid aggressive bagging during cardiopulmonary resuscitation.




Reference: click to get article

Auto-PEEP and Electromechanical Dissociation - Volume 335:674-675, Number 9, August 29,1996, NEJM

Sunday December 7, 2008


Q: 36 year old male with history of pulmonary hypertension is admitted to ICU with shortness of breath. List of medication includes Revatio. What is Revatio?

A: Revatio is another trade name for Sildenafil (Viagra). The white, round pills looks different from Viagra's blue diamond shape. This is to avoid embarassment for patients with pulmonary hypertension, if they present to pharmacy with Sildenafil prescription. Moreover, it helps to avoid confusion in medical history part.

Saturday December 6, 2008
Dosing of Esmolol

Q: How much time does it take for esmolol to reach steady-state blood levels, if you don't use loading dose for esmolol infusion?

A: Using an appropriate loading dose, steady-state blood levels of Esmolol for dosages from 50-300 mcg/kg/min (0.05-0.3 mg/kg/min) are obtained within 5 minutes, otherwise it takes 30 minutes to reach steady-state without the loading dose. Steady-state blood levels of Esmolol increase linearly over this dosage range and elimination kinetics are dose-independent over this range.

Esmolol dosing guideline:

An initial loading dose of 0.5 milligrams/kg (500 micrograms/kg) infused over a minute duration followed by a maintenance infusion of 0.05 milligrams/kg/min (50 micrograms/kg/min) for the next 4 minutes is recommended. This should give a rough guide with respect to the responsiveness of ventricular rate.

After the 4 minutes of initial maintenance infusion (total treatment duration being 5 minutes), depending upon the desired ventricular response, the maintenance infusion may be continued at 0.05 mg/kg/min or increased step-wise (e.g. 0.1 mg/kg/min, 0.15 mg/kg/min to a maximum of 0.2 mg/kg/min) with each step being maintained for 4 or more minutes.

If more rapid slowing of ventricular response is imperative, the 0.5 mg/kg loading dose infused over a 1 minute period may be repeated, followed by a maintenance infusion of 0.1 mg/kg/min for 4 minutes. Then, depending upon ventricular rate, another (and final) loading dose of 0.5 mg/kg/min infused over a 1 minute period may be administered followed by a maintenance infusion of 0.15 mg/kg/min. If needed, after 4 minutes of the 0.15 mg/kg/min maintenance infusion, the maintenance infusion may be increased to a maximum of 0.2 mg/kg/min.

In the absence of loading doses, constant infusion of a single concentration of esmolol reaches pharmacokinetic and pharmacodynamic steady-state in about 30 minutes. Maintenance infusions (with or without loading doses) may be continued for as long as 24 hour.

Esmolol (Brevibloc) - rxlist.com

Friday December 5, 2008
Is Traditional Reading of the Bedside Chest Radiograph Appropriate To Detect Intraatrial Central Venous Catheter Position?

Background:Traditionally, the positioning of central venous catheters (CVCs) outside the right atrium (RA) in patients receiving intensive care is determined by surrogate landmarks on bedside chest radiographs (CXRs). The validity of this method was examined by comparing readings of radiologists with the results of transesophageal echocardiography (TEE).

Methods: Prospective study at university hospital. Two hundred thirteen adults scheduled for cardiothoracic surgery were randomized to right or left internal jugular vein catheterization under ECG guidance. One senior radiologist and two radiologists in training independently read the CXRs, and determined whether the CVC tip ended in the RA and measured the vertical distance from the CVC tip to the carina (TC-distance).

Results:Two hundred twelve CVC tips could be identified by TEE. Only left-sided CVCs (n = 5) ended in the upper RA (2.4%). Three of those patients were shorter than 160 cm. Specificity was 94% for senior radiologist, 44% for the first radiologist in training, and 60% for the second radiologist in training. The TC-distance of intraatrial catheters was 39, 55, 59, 80, and 83 mm, respectively. Thus, a TC-distance 55 mm ensured extraatrial tip position in four of five intraatrial CVCs (80%, p = 0.002). The TC-distance of extraatrial catheters ranged from – 26 to 102 mm.

Conclusions: Reading of a bedside CXR alone is not very accurate to identify intraatrial CVC tip position. TC-distance is a helpful marker, and its specificity is as good as that of an experienced radiologist if a cutoff value of 55 mm is chosen.


Reference: click to get article

Is Traditional Reading of the Bedside Chest Radiograph Appropriate To Detect Intraatrial Central Venous Catheter Position? - Chest. 2008; 134:527-533

Thursday December 4, 2008
Artificial intelligence in ICU !!

A very interesting study - "An artificial intelligence tool to predict fluid requirement in the intensive care unit: a proof-of-concept study" - is just published at ccforum.com

An alternative way of personalizing medicine in the ICU on a realtime basis by using information derived from the application of artificial intelligence on a high resolution database, is proposed. Calculation of maintenance fluid requirement at the height of systemic inflammatory response was selected to investigate the feasibility of this approach.

The Multi-parameter Intelligent Monitoring for Intensive Care II (MIMIC II) is a database of patients admitted to the Beth Israel Deaconess Medical Center ICU.

METHOD: Patients who were on vasopressors for more than 6 hours during the first 24 hours of admission were identified from the database. Demographic and physiologic variables that might affect fluid requirement or reflect the intravascular volume during the first 24 hours in the ICU were extracted from the database. The outcome to be predicted is the total amount of fluid given during the second 24 hours in the ICU, including all the fluid boluses administered.

Investigators represented the variables by learning a Bayesian network from the underlying data. Using ten-fold cross-validation repeated 100 times, the accuracy of the model in predicting the outcome is 77.8%. The network generated has a threshold Bayes factor of 7 representing the posterior probability of the model given the observed data. This Bayes factor translates into p < .05 assuming Gaussian distribution of the variables.

Conclusions: Based on the model, the probability that a patient will require a certain range of fluid on day 2 can be predicted. In the presence of a larger database, analysis may be limited to patients with identical clinical presentation, demographic factors, co-morbidities, current physiologic data, and those who did not develop complications as a result of fluid administration. By better predicting maintenance fluid requirements based on the previous day's physiologic variables, one might be able to prevent hypotensive episodes requiring fluid boluses during the course of the following day.


Reference: click to get article

An artificial intelligence tool to predict fluid requirement in the intensive care unit: a proof-of-concept study - Critical Care 2008, 12:R151 - pdf file

Wednesday December 3, 2008
Sodium retention in Corticosteroids


Q; Which Corticosteroid has highest Relative Sodium Retension (RSR)?
- Choose one

A) Prednisone
B) Methylprednisone
C) Hydrocortisone
D) Dexamethasone




Answer: Hydrocortisone

Hydrocortisone has Relative Sodium Retention of "20" in comaprison to other steroids

Prednisone's RSR is 1

Methylprednisone RSR is 0.5

Dexamethasone RSR is 0

Tuesday December 2, 2008
Hepatic Hydrothorax

Q; How you confirm the cause of pleural effusion (mostly right sided) in cirrhotic patient as hepatic hydrothorax?


Answer: By radioisotope imaging (nuclear medicine)

Pleural effusion in cirrhotic patients (hepatic hydrothorax) may result from migration of ascitic fluid across defects in the diaphragm. Biochemical analysis of ascitic and pleural fluid provides only indirect information about the nature and origin of the effusion.

Transdiaphragmatic movement of ascitic fluid into the pleural space can be demonstrated, generally within 2 hours of intraperitoneal injection of the radiotracer ( 99mTc sulfur colloid scintigraphy).

Radionuclide scintigraphy is a simple, safe and relatively non-invasive method to confirm passage of ascitic fluid across the diaphragm.

Monday December 1, 2008

Life Cycle of Malaria (still image below)