Tuesday, May 31, 2016

Q: 28 year old male presented to ED with chest pain after inhalation of crack cocaine. CXR showed pneumomediastinum which was confirmed by CT scan. What is the modus operandi of pneumomediastinum associated with inhalation of crack cocaine?


Answer: There is a general misconception that pneumomediastinum (and/or pneumothorax) associated with crack cocaine is due to drug itself. Actually, it is  likely due to valsalva maneuver usually performed after inhalation. This is the reason that pneumomediastinum (and/or pneumothorax) is a rare occurrence after intranasal cocaine. It may be interesting to know that it is a common practice among crack cocaine smokers not only to perform a valsalva maneuver after inhalation but partners also exhale forcefully into each other's mouths (to increase uptake of the drug), causing  pneumothorax, pneumomediastinum, or even pneumopericardium due to barotrauma.


References:

1. Maeder M, Ullmer E. Pneumomediastinum and bilateral pneumothorax as a complication of cocaine smoking. Respiration 2003; 70:407. 

2. Alnas M, Altayeh A, Zaman M. Clinical course and outcome of cocaine-induced pneumomediastinum. Am J Med Sci 2010; 339:65.

Monday, May 30, 2016

Q: Chest-Xray immediately after pneumonectomy shows postpneumonectomy space filled with air. At what rate fluid accumulates in the empty postpneumonectomy space?


Answer: At a rate of one to two intercostal spaces per day. 

CXR immediately after postpneumonectomy shows relatively clear, stable CXR with trachea at midline and the postpneumonectomy space filled with air. After a day, CXR findings become apparent with elevation of  ipsilateral hemidiaphragm  and the mediastinum shifting towards postpneumonectomy side. Fluid accumulates at a rate of one to two intercostal spaces per day, and it takes about 2 weeks to  postpneumonectomy space filled with fluid.


Reference:

Munden RF, O'Sullivan PJ, Liu P, Vaporciyan AA. Radiographic evaluation of the pleural fluid accumulation rate after pneumonectomy. Clin Imaging 2015; 39:247.

Sunday, May 29, 2016

Q: On agitated saline contrast echocardiography, appearance of bubbles in the left heart within how many beats after contrast opacification of the right atrium is highly suggestive of intracardiac shunt, mostly PFOs? (Read suggestive not diagnostic)

A)  There is no correlation

B)  At least 3 beats
C) At least 5 beats
D) At least 7 beats 
E) Requires full one minute of wait


Answer: B

The Objective of above question is to emphasize the importance of timing of the appearance of agitated saline contrast, popularly called bubbles, in the left heart on echocardiography. Early contrast appearance in the left heart - within three beats of contrast appearance in the right heart - suggests intracardiac shunting like PFO or ASD. But if it takes more than 3 beats for contrast to appear in the left heart after a contrast opacification of the right atrium is more suggestive of  pulmonary arteriovenous shunting. Please note, this is just a rule of thumb, as there have been reports in the literature of failure of this 3 beats rule.  All ECHOs should be strongly read in correlation with other data and clinical scenarios.




References: 

Woods TD, Patel A. A critical review of patent foramen ovale detection using saline contrast echocardiography: when bubbles lie. J Am Soc Echocardiogr 2006; 19:215. 

Freeman JA, Woods TD. Use of saline contrast echo timing to distinguish intracardiac and extracardiac shunts: failure of the 3- to 5-beat rule. Echocardiography 2008; 25:1127.

Saturday, May 28, 2016

Q: Majority of cardiac tumors are myxomas. From which chamber they tend to arise most?

A) Left Atrium
B) Right Atrium
C) Left Ventricle
D) Right Ventricle
E) Left Atrial appendage


Answer: A 

Fortunately three fourth of cardiac tumors are benign, and require removal to avoid risk of embolization and obstructive heart failure. Majority of these are myxomas. 80 percent of myxomas arise in the left atrium and rest in the right atrium. 



Reference: 

 Keeling IM, Oberwalder P, Anelli-Monti M, et al. Cardiac myxomas: 24 years of experience in 49 patients. Eur J Cardiothorac Surg 2002; 22:971.

Friday, May 27, 2016

Case: 22 year old male student from Taiwan is admitted to ICU with severe left flank pain and hematuria. According to patient he has episodes of bloody urine since childhood but this time this is associated with flank pain on left side. Previously, he was ruled out for any cancer or kidney disease, but was told he may need some kind of stent!


Answer: Nutcracker syndrome 

Nutcracker syndrome is a compression of the left renal vein between the aorta and proximal superior mesenteric artery. This is primarily a disease of children but also been found in Asian adults. The hematuria can be asymptomatic or may be associated with left flank pain. Diagnosis is usually quick via radiological workup and can be treated with either stent or surgical intervention.




References: 

1.  Zhang H, Li M, Jin W, et al. The left renal entrapment syndrome: diagnosis and treatment. Ann Vasc Surg 2007; 21:198. 

2. Hanna HE, Santella RN, Zawada ET Jr, Masterson TE. Nutcracker syndrome: an underdiagnosed cause for hematuria? S D J Med 1997; 50:429.

Thursday, May 26, 2016

Q: What is the best place for feeding tube to be at during management of acute pancreatitis?


Answer:  Jejunum

In pancreatitis, jejunal feed is preferred as it minimize the stimulation of pancreatic exocrine secretions. Ideally, in ICU patients, position of post-pyloric feeding tube is beyond the ligament of Treitz. It does not mean that patients can't be feed in gastric or earlier parts of duodenum. Risks and benefits should be considered as enteral feed is vital for prevention of sepsis in ICU patients.


Reference:

1. McClave SA, Chang WK, Dhaliwal R, Heyland DK. Nutrition support in acute pancreatitis: a systematic review of the literature. JPEN J Parenter Enteral Nutr 2006; 30:143.

Wednesday, May 25, 2016

Q: How the "sniff" test works for unilateral hemidiaphragm paralysis?


Answer: "Sniff" test, now known for almost 50 years,  is performed in radiology department under fluoroscope, while the patient sniffs forcefully. The sniff test shows paradoxical elevation of the paralyzed hemidiaphragm with inspiration compared with the rapid descent of the normal hemidiaphragm. Sniff test is positive in more than 90% of patients.  Once patient is comfortable with normal breathing, the patient is asked to take a few quick short breaths in with a closed mouth causing rapid inspiration. This maneuver is repeated in the lateral projection  to evaluate the posterior hemidiaphragms. The affected hemidiaphragm does not move downwards during inspiration or paradoxical motion may occur.


Reference: 

Alexander C. Diaphragm movements and the diagnosis of diaphragmatic paralysis. Clin Radiol 1966; 17:79.

Tuesday, May 24, 2016

Q: In Myasthenia Gravis (MG), to assess the muscle strength - Vital Capacity can be measured both in sitting and supine position. Diaphragmatic weakness is more apparent in which position?


Answer:  Supine

Vital Capacity (VC) is the most commonly and easily used quick assessment at bedside to assess the mechanical function of both inspiratory and expiratory muscle strength. Diaphragmatic weakness is more apparent on the supine VC measurement. But generally sitting position measurement is well accepted as a cut off point to transfer patient from floor/ward to ICU. 

Important clinical lessons learned from pitfalls of VC measurement are:

1. It is not the absolute number at VC but the "speed" of a downward trend in VC. It should be measured frequently, as often as every hour as patients  may precipitously fatigue and go in rapid development of respiratory failure before a downward trend in VC is evident.


2. Many patients with facial weakness caused by myasthenia gravis may have a falsely low VC. 

3. Hypoxemia and hypercarbia are insensitive measures of respiratory muscle weakness, and ABG should not be relied on too much but progressive hypercarbia indicates quickly failing respiratory system.



Reference:

 Rabinstein AA, Wijdicks EF. Warning signs of imminent respiratory failure in neurological patients. Semin Neurol 2003; 23:97.

Monday, May 23, 2016

Q: In patients undergoing hip surgery and are at increased risk for bleeding, and in whom both mechanical and pharmacologic prophylaxis are contraindicated, placement of an inferior vena cava filter is recommended - True or False?


Answer: False 

According to 2012, the American College of Chest Physicians (ACCP) guidelines  for Venous Thrombotic Embolism (VTE) prevention in orthopedic surgery patients, based on the evidence-based clinical practice, patients undergoing hip surgery and are at increased risk for bleeding, and in whom both mechanical and pharmacologic prophylaxis are contraindicated, placement of a prophylactic inferior vena cava filter is not recommended, as risks of IVC filter is higher than risk of possible Deep venous Thrombosis(DVT).


 Reference: 

Falck-Ytter Y, Francis CW, Johanson NA, Curley C, Dahl OE, Schulman S, et al. Prevention of VTE in orthopedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb. 141 (2 Suppl):e278S-325S

Sunday, May 22, 2016

Q: Hypoxia is an early sign of pulmonary contusion. True or False?

Answer:  False 

In the early presentation of pulmonary contusion, hypoxia is rare unless a patient is affected with severe bilateral chest trauma. It takes about 24 to 48 hours before hypoxia starts to manifest due to the following development of ARDS. Also, pain from severe chest wall trauma affects patient ability to ventilate and contributes to hypoxemia.



Reference:

Miller PR, Croce MA, Kilgo PD et al. 'Acute respiratory distress syndrome in blunt trauma: identification of independent risk factors.' Am Surg 2002;68:845-50

Saturday, May 21, 2016

Q: What are the major characteristics of Short QT Syndrome (SQTS)?

Answer:

  • QT interval, usually less than 360 msec (range of 220 to 360 msec)
  • Absence of ST segment 
  • Tall and peaked T waves in the precordial leads
  • Poor rate adaptation of QT interval 



Friday, May 20, 2016

Q: During intubation of a morbidly obese patient via Rapid Sequence Intubation (RSI), neuromuscular blockade (NMB) should be used by calculating (select one)

A) lean body weight (LBW) 
or
B)  total body weight (TBW) 


Answer: B

Intubation, and particularly emergent intubation can be very tricky in obese patients. Proper preparation with positioning, pre-oxygenation, rescue back-up, available equipments and proper dosing of medications are keys to a success. During intubation of an obese patient via RSI in an obese patient, induction agents are preferred to be calculated by lean body weight (LBW), and neuromuscular blockers with the calculation of total body weight (TBW).

* Lean body weight is many times confused with ideal body weight (IBW). They can be markedly different in an obese patient. Pharmacy or online tools usually have quick calculators to provide medicine dosing depending either on IBW or LBW.

Thursday, May 19, 2016

Q: There are how many grades of liver injury?


Answer:  6

According to American Association for the Surgery of Trauma (AAST) classification system, there are 6 levels of hepatic injury from subcapsular hematoma less than 10 percent surface area (grade 1) to hepatic avulsion (Grade 6) - Please refer to references for detailed grading.

Clinical significance: The likelihood of success with nonoperative management, is higher for Grade I, II and III, when compared to higher grades, like patients with hepatic avulsion definitely requires surgical intervention.



References:

1.  Moore EE, Cogbill TH, Jurkovich GJ, et al. Organ injury scaling: spleen and liver (1994 revision). J Trauma 1995; 38:323.

2. Tinkoff G, Esposito TJ, Reed J, et al. American Association for the Surgery of Trauma Organ Injury Scale I: spleen, liver, and kidney, validation based on the National Trauma Data Bank. J Am Coll Surg 2008; 207:646. 

Wednesday, May 18, 2016

Q; Which of the following  anticonvulsants is effective in uremic pruritus patients on hemodialysis?

A) Gabapentin
B) Phenytoin
C) levetiracetam
D) Fosphenytoin
E) Carbamazepine


Answer:  A

Gabapentin is shown to be effective in uremic pruritus. For patients who don't respond to pruritus despite emollients and/or topical analgesics, and oral antihistamines - gabapentin is an effective choice. The starting dose is 100 mg and maximum dose is 350 mg given after each hemodialysis session. Another effective drug on same line is pregabalin (lyrica).



Reference: 

1. Gunal AI, Ozalp G, Yoldas TK, et al. Gabapentin therapy for pruritus in haemodialysis patients: a randomized, placebo-controlled, double-blind trial. Nephrol Dial Transplant 2004; 19:3137. 

2. Naini AE, Harandi AA, Khanbabapour S, et al. Gabapentin: a promising drug for the treatment of uremic pruritus. Saudi J Kidney Dis Transpl 2007; 18:378. 

3. Shavit L, Grenader T, Lifschitz M, Slotki I. Use of pregabalin in the management of chronic uremic pruritus. J Pain Symptom Manage 2013; 45:776. 

Tuesday, May 17, 2016

Q: Flecainide toxicity can be seen on EKG as (select one)

A) QRS prolongation
B) QTc interval prolongation
C) inversion of T wave
D) U wave
E) J point elevation


Answer:  QRS prolongation

Signs of flecainide toxicity are sometime not so apparent and early and best monitoring is looking at EKG (or Telemetry pattern). Flecainide toxicity should be suspected if there is a 50% increase in QRS duration or 30% prolongation in PR interval, especially at rapid heart rates. 



Reference: 

 1. Katristis D, Rowland E, O'Nunain S, Shakespeare C, Poloniecki J, Camm A (1995). "Effect of flecainide on atrial and ventricular refractoriness and conduction in patients with normal left ventricle Implications for possible antiarrhythmic and proarrhythmic mechanisms". Eu Heart J 16 (1): 1930–1935 


2.  Lloyd T, Zimmerman J, Griffin GD. Irreversible third-degree heart block and pacemaker implant in a case of flecainide toxicity. Am J Emerg Med. 2013;31:1418.e1-2. 

3. Courand PY, Sibellas F, Ranc S, Mullier A, Kirkorian G, Bonnefoy E. Arrhythmogenic effect of flecainide toxicity. Cardiol J. 2013;20:203-205. 

4. Levis JT. ECG diagnosis: flecainide toxicity. Perm J. 2012;16:53. 

5. Rognoni A, Bertolazzi M, Peron M, et al. Electrocardiographic changes in a rare case of flecainide poisoning: a case report. Cases J. 2009;3:9137. 

Monday, May 16, 2016

Q: Which of the following is found to resolve the acute episode of sweet syndrome (acute febrile neutrophilic dermatosis)?

A) Methotrexate 
B) IV antibiotics
C) Potassium iodide
D) Aspirin
E) Hemodialysis


Answer: C

Steroids are well known to help in Sweet Syndrome but potassium iodide is found to be equally effective, resolving fever within 2 days and cutaneous lesions within 3-4 days.Recommended dose is 300 mg of potassium iodide three times daily. Modus operandi of Potassium Iodide in Sweet Syndrome is thought to be immune suppression. Patient should be watched for pulmonary edema.

Sunday, May 15, 2016

Q; 32 year old female is admitted for observation in ICU with severe headache associated with nausea and vomiting. workup in ED and consult with neurology ruled out any subarachnoid hemorrhage(SAH) or any other acute etiology. Patient acknowledge that this headache is similar to her previous episodes of migraine. In view of associated nausea and vomiting, you prescribed 10 mg of IV metoclopramide. Which one other medicine you should add as a part of treatment?


Answer: Couple of doses of IV diphenhydramine

Various treatments are now available for treatment of moderate to severe migraine headache. In migraines associated with nausea and vomiting, very commonly mono-therapy with 10-20 mg of  intravenous metoclopramide or prochlorperazine works well. It is like killing 2 birds with one stone.  Objective of above question is two folds. First, to emphasis that oral agents do not work well in migraine due to gastric stasis causing poor absorption. Second, adding IV diphenhydramine preemptively block any akathisia and other dystonic reactions, which is expected in migraine patients getting treated with metoclopramide or prochlorperazine.



Reference:

Marmura MJ, Silberstein SD, Schwedt TJ. The acute treatment of migraine in adults: the american headache society evidence assessment of migraine pharmacotherapies. Headache 2015; 55:3.

Saturday, May 14, 2016

Q: All of the following can be used in Neuroleptic Malignant Syndrome (NMS) except

A) Dantrolene,
B) Bromocriptine,
C) Lorazepam
D) Haloperidol 
E) Amantadine


Answer:  D

Objective of above question is to identify the drugs which are commonly get prescribed in ICU and may cause NMS. Commonly known implicated drugs causing NMS are haloperidol, fluphenazine, chlorpromazine, clozapine, risperidone, olanzapine, metoclopramide, promethazine and few others. It is of utmost importance to know that NMS can occur after a single dose of these drugs. As expected, higher doses and parenteral administrations are relatively at higher risk.


References:

1. Seitz DP, Gill SS. Neuroleptic malignant syndrome complicating antipsychotic treatment of delirium or agitation in medical and surgical patients: case reports and a review of the literature. Psychosomatics 2009; 50:8


2. Kogoj A, Velikonja I. Olanzapine induced neuroleptic malignant syndrome--a case review. Hum Psychopharmacol 2003; 18:301

Friday, May 13, 2016

Q: 48-year-old Chinese female is admitted to ICU with hypertensive crisis. The patient appears with classic signs of Cushing syndrome like moon face, supraclavicular fat pads, buffalo hump, truncal obesity, and purple striae. Endocrinology service is consulted and patient indeed get diagnosed with Cushing syndrome with probable iatrogenic cause. To your surprise, while taking history, patient drug list does not include any glucocorticoids. Which one part of the history may help to find the missing piece of the puzzle?


Answer: History of herbal intake

Many herbal preparations contain corticosteroids and they often go unnoticed during history taking. In such cases, there should be a gradual withdrawal and discontinuation of the causative drug.



Thursday, May 12, 2016

Q: For hemothorax, minimally what size of chest tube should be inserted?


Answer: 36 F

If hemothorax is suspected, for efficient drainage minimally 36 French size of chest tube should be inserted. Also if pneumothorax is evident with hemothorax (hemopneumothorax), it would be helpful to insert two chest tubes, with one tube draining the pneumothorax placed in a more antero-superior place. In event of drainage of more than 1000-1500 mL of blood via chest tube after insertion or continuous output of  150-200 mL/hr for 2 hours, patient should be strongly considered for surgical thoracotomy. Obviously, supportive care should be provided with transfusions and hemodynamic management.

Wednesday, May 11, 2016

Q: Which provides a better measurement of coagulopathy in hepatic patients before an invasive procedure?

A) INR
B) PTT
C) TEG
D) Platelets 
E) Bleeding time


Answer:  C

 INR as a target to measure bleeding risk do not apply to patients with hepatic coagulopathy, as it has a completely different pathway of pathophysiology. Actually, assessment of global clot formation provides better approach like thromboelastography (TEG) (or rotational thromboelastometry - ROTEM). FFP may be required if the reaction time (r) is more than 40 minutes and platelets if the maximum amplitude (MA) is less than 30 mm. TEG and ROTEM in patients with hepatic coagulopathy decrease the use of blood product.


Reference:

De Pietri L, Bianchini M, Montalti R, et al. Thrombelastography-guided blood product use before invasive procedures in cirrhosis with severe coagulopathy: A randomized, controlled trial. Hepatology 2016; 63:566.

Tuesday, May 10, 2016

Q:  Risk of herpes bronchopneumonia goes high in ventilated patients after how many days?


Answer: Five

It has been shown that 20% of ICU patients who stays on ventilator for more than 5 days, develops herpes bronchopneumonia and these patients shows longer time on mechanical ventilation and longer ICUs length of stay.


Reference: 

 Luyt CE, Combes A, Deback C, et al. Herpes simplex virus lung infection in patients undergoing prolonged mechanical ventilation. Am J Respir Crit Care Med. 2007;175:935-942

Monday, May 9, 2016


Role of Amantadine after severe Traumatic Brain Injury (TBI)

Amantadine with the dose of 100 mg two times a day, has been studied in patients who get transferred to the rehabilitation center in a vegetative or a semi-vegetative state after severe TBI and found to be associated with accelerated recovery, particularly during the first month of admission. Afterward, the effect may plateau out. The mechanism of action  is thought to be the antagonism of N-methyl-D-aspartate and/or indirect agonsim of dopamine. Due to chances of higher benefits than risks, there is no harm to try out Amantadine in patients who after the acute phase of severe TBI goes into a vegetative or a semi-vegetative state. 


Reference:

 Giacino JT, Whyte J, Bagiella E, et al. Placebo-controlled trial of amantadine for severe traumatic brain injury. N Engl J Med 2012; 366:819.

Sunday, May 8, 2016

"Effect of positive pressure ventilation on lymphatic drainage"

The lymphatics subserve at least two functions, drainage and defence. The lung has a massive surface area continuously exposed to a large volume of poorly filtered air. Fluid is drained from the interstitium by the reticuloendothelial system that removes extraneous material before it reaches the circulation. The lung lymphatics consist of thin, single cell, conduits within the interstitium with valves to assist unidirectional flow. During inspiration, the negative pressure in the lung is transmitted to the interstitium and to the lymphatics and a gradient allows fluid to drain into the lymphatics. This is highly efficient and lymph flow can increase considerably if needed.

 Positive pressure ventilation will push fluid from alveolus towards the interstitium and potentially towards and into the lymphatics. The positive pressure on the interstitium may compress some peripheral lymphatics potentially aiding flow, but it may also compress these thin-walled vessels impeding flow. A second effect is that high CVPs associated with ventilation will form a significant hydrostatic barrier to flow, given that the lymphatic pressure is usually in single figures.Lymph flow is again impeded. During expiration, lower intrathoracic pressure and decreasing CVPs may allow resumption of flow, but the use of PEEP, especially high PEEP, may obviate this recovery.

Positive pressure ventilation increases lung water as does PEEP. PEEP helps remove fluid from alveoli, but the reduction in thoracic duct drainage results in fluid retention in the interstitium. Airway pressure of 15 mm Hg or higher compresses thin-walled collapsible lymphatics. The lymphatics drain into the central veins characterized by the superior vena cava (SVC). If the SVC pressure is high, 12 mm Hg in this example, drainage will be impeded. Hence both airway pressures and venous pressures will potentially impede drainage. In the deliberately injured lung, PEEP increases lymph production but impairs lymph flow.

 The net effect of impaired drainage over time would be fluid accumulation in the lung and pleural spaces and potentially increased susceptibility to lung infection. In the lung, there is no direct evidence linking impaired lymphatic drainage to infection risk but elsewhere, such as with chronic lymphoedema there is both fluid sequestration and predisposition to infection."


Read full article:  N. Soni and P. Williams: Positive pressure ventilation: what is the real cost?: Br. J. Anaesth. (2008) 101 (4): 446-457.

Weblink: http://bja.oxfordjournals.org/content/101/4/446.full

Saturday, May 7, 2016

Q: 24-year-old male is admitted to ICU from ED. The Patient had scorpion bite 3 hours ago and required intubation in ED for the protection of Airway. Pharmacy notified you that anti-venom has been arranged and should be available in an hour. Which analgesia should be avoided?


Answer: Morphine

Morphine may cause histamine release with the administration of anti-venom. Fentanyl is a preferred choice of analgesia. It is commonly misconceived that scorpion venom without anti-venom would be fatal. Most adult patients survive with supportive treatment. Antivenom is recommended to decrease the duration of  symptoms and to avoid rare but possible life-threatening complications like blurred vision, slurred speech, tongue fasciculations, hypersalivation (causing aspiration and respiratory failure), abnormal eye movements, restlessness, fasciculations, alternating opisthotonos, and emprosthotonos, hyperthermia, pancreatitis and others.

Friday, May 6, 2016

Q: What is the pathophysiology behind acalculous cholecystitis in ICU patients?


Answer: 

3 major factors behind highly life threatening acalculous cholecystitis in severely sick patients are

  • Increased bile viscosity due to dehydration
  • Absence of cholecystokinin-induced gallbladder contraction due to prolonged absence of oral feeding (seen in patients on long-term TPN)
  • Gallbladder wall ischemia due to a low-flow state 

Thursday, May 5, 2016

Q: 26 year old female is admitted to ICU with shortness of breath, and on exam found to have bilateral pleural effusion, swelling of both legs and yellowish-greenish nails. Consultant diagnosed it as Yellow Nail Syndrome.


Answer: Yellow nail syndrome is characterized by
  • pleural effusions
  • bilateral lymphedema 
  • yellow dystrophic nails
Half of the patients may also have bronchiectasis and chronic sinusitis. Lymphedema is due to underdevelopment of the lymphatic vessels. Genetic link is suspected but not proven. Treatment is symptomatic. Octreotide has been proposed as a treatment particularly when effusion is chylothorax. It is reported to improve lymphedema too.



Reference:

1. Hillerdal G - Yellow nail syndrome: treatment with octreotide. - Clin Respir J. 2007 Dec;1(2):120-1. 

2. Martin Riedel, MD -Images in Cardiovascular Medicine Multiple Effusions and Lymphedema in the Yellow Nail Syndrome - Circulation. 2002; 105: e25-e26

Wednesday, May 4, 2016

Q: Patient returned from OR after repair of thoracic aneurysm repair. On weaning of sedation lower extremities weakness is noted. MAP is progressively increased, along with draining of cerebero-spinal-fluid (CSF) to keep Intra-cranial pressure (ICP) at 10-12. But despite maximum perfusion therapy, patient lower extremities remained weak. What should be your concern?


Answer: Epidural hematoma

If despite maximum perfusion therapy, patient remain unresponsive, prompt radiological study should be obtained (MRI vs CT) to rule out epidural hematoma. 

Tuesday, May 3, 2016

Q: What is the modus operandi of hyponatremia during loop diuresis? 


Answer:  There is a common misconception that hyponatremia during loop diuresis is due to direct excretion of sodium. In fact, hyponatremia occurs due to hypovolemia-induced release of antidiuretic hormone.

Monday, May 2, 2016

Q: 58-year-old male with End Stage Renal Disease (ESRD) is admitted to ICU with septic shock. The patient is well known to service as a 'vasculopath' and known to have no upper body vessels available for CVC cannulation. The patient is also known to have IVC filter. Which one trick should be used while placing femoral CVC to minimize the risk of dislodgement of IVC filter?


Answer: Using the non-J tip side of wire to insert CVC line

If a patient is known to have IVC filter, the femoral approach should be avoided as much as possible as guidewire may either displace or get entangle in IVC filter. But in  the situations, where femoral approach becomes the only viable site to insert CVC, the other side of J-wire (non-J side) should be used, as most of the IVC filter displacement, dislodgement or entanglement occurs via J-tip. KUB should be obtained after insertion of CVC to confirm IVC filter's positioning.




References:

1. Wu A, Helo N, Moon E, et al. Strategies for prevention of iatrogenic inferior vena cava filter entrapment and dislodgement during central venous catheter placement. J Vasc Surg 2014; 59:255. 

2. Vinces FY, Robb TV, Alapati K, et al. J-tip spring guidewire entrapment by an inferior vena cava filter. J Am Osteopath Assoc 2004; 104:87. 

Sunday, May 1, 2016

Q: How propofol directly affects cardiac muscles?


Answer:  Propofol effect on myocardium gets pronounced during Propofol Infusion Syndrome (PRIS). It has direct calcium channel blocking properties in myocardium and also promotes inflammation in the cardiac muscle.



References: 

1. W. Zhou, H. J. Fontenot, S. Liu, and R. H. Kennedy, “Modulation of cardiac calcium channels by propofol,” Anesthesiology, vol. 86, no. 3, pp. 670–675, 1997. 

2. W. Jiang, Z.-B. Yang, Q.-H. Zhou, X. Huan, and L. Wang, “Lipid metabolism disturbances and AMPK activation in prolonged propofol-sedated rabbits under mechanical ventilation,” Acta Pharmacologica Sinica, vol. 33, no. 1, pp. 27–33, 2012.