Thursday, August 28, 2014

It's 3:00 AM and you want to do a thoracentesis?

Today in our Grand Morning Report, we discussed a common clinical dilemma that many Senior Medical Residents (SMR) face on call across the city:

This patient has a pleural effusion and it's 3:00 AM, should I perform a thoracentesis?

I would argue that there is really only one absolute, emergency indication to perform a thoracentesis on call (overnight) as an SMR covering the GIM service.

This being the old adage, "never let the sun set on an empyema".

If an SMR suspects empyema clinically, for example imaging confirms a loculated pleural effusion and the patient is febrile, than I believe the sun should not set, or in the case of our SMR's overnight, the sun should not rise before that pleural effusion is sampled and sent for culture.

This may require calling interventional radiology or thoracic surgery to provide assistance.

In my practical experience as an SMR at Sunnybrook Hospital, all that is needed overnight is an adequate sample to perform the necessary tests, mainly a sterile specimen for culture and gram stain, and to perform basic biochemistry (pH, cell count, protein, LDH).  This usually amounts to a 20 cc specimen, and no more.

Time... it is a precious commodity on call!

Practically on call, there is very little time to do a full therapeutic thoracentesis and drain off 1000 mL of fluid, so once the diagnostic sample is obtained, I would finalize the procedure and move on to the rest of your clinical duties.

It would not be an ideal scenario to be called to attend a Code Blue, while you are in the midst of draining off a large pleural effusion, and a needle is in the patient's back.

But... What if the patient is in respiratory distress and I feel that removing the fluid will alleviate their symptoms?

I would argue that the risks of performing a therapeutic thoracentesis overnight far outweigh the potential benefit.  If a patient is in such significant respiratory distress, that you want to insert a needle into their pleural cavity, they most likely will not have a significant clinical change from taking off 1000 mL of fluid.  

A unilateral pleural effusion is often not the only cause of the respiratory distress.  It usually takes an insult to both lungs to cause significant respiratory distress in most patients.  It is probably the presence of the underlying disease process such as pneumonia, congestive heart failure, malignancy, or pulmonary embolus that may be causing both the pleural effusion, and  the respiratory distress.

My suggestion in this circumstance would be to treat the underlying cause, such as giving lasix to a patient with CHF and a pleural effusion, provide supplemental oxygen (such as optiflow, or BiPAP), and if they are truly in respiratory distress, then these patients should be in a monitored setting (ICU or step down unit) as they will most likely require intubation or ventilatory support.  If it is patient discomfort that is the major problem, than providing symptom relief along with supplemental oxygen should be the way to go overnight.

What is the risk of performing a thoracentesis overnight?

Most of the literature points out that a bedside thoracentesis without the use of an ultrasound at the best of times carries a risk of pneumothorax between 4 - 30%, and approximately half of these patients will require insertion of a chest tube (Jones et. al, 2003).  Overnight, when an SMR has time constraints, and is fatigued this number is likely on the higher side.

Even with the use of ultrasound, the rates of pneumothorax were 2.5% among experienced interventional radiologists.

I love point of care ultrasound, but I am not an experienced interventional radiologist!

The Bottom Line:  

The last thing you want to do to a patient at 3:00 AM with significant respiratory distress is cause a pneumothorax as this may significantly worsen an already unstable situation.

The safe SMR knows when to subject a patient to a significant risk of harm, but more importantly knows when not to perform a procedure (especially overnight when there is very little support around).

If you're not ruling out empyema, don't stick a needle into the chest.  If the case is particularly challenging, call thoracic surgery or interventional radiology for assistance.  If the patient is unstable, call the ICU and if they are symptomatic, treat the symptoms and wait until the heavy cavalry arrives in the morning, and their is enough support around to safely perform the thoracentesis and deal with any serious complications.

A great reference on the rates of pneumothorax in the ultrasound era.  See reference below!

Ultrasound-Guided Thoracentesis: Is it a safer method? Jones, et. al. CHEST. 2003. 123: 418-423.

Wednesday, August 13, 2014

Thyroid Storm

Endocrine Emergency - Thyroid Storm

The theme for the week is management of the patient with critical illness, and today in Morning Report we discussed a case of thyroid storm.  This has been blogged before on Tangent's, but I wanted to focus more on the management of this medical emergency.

We also discussed the other thyroid related emergencies that might result in a patient being admitted to the ICU, mainly myxedema coma, which is the polar opposite of thyroid storm and hypokalemic periodic paralysis which classically presents as paralysis in male patients of Asian ancestry who are hyperthyroid.

Thyroid Storm:

In terms of thyroid storm, the Burch-Wartofsky scoring system is probably the most widely utilized clinical scoring system for making a diagnosis of thyorid storm.  The key clinical features in this scoring system include thermoregulatory dysfunction, CNS effects, GI-hepatic dysfunction, and cardiovascular dysfunction (including congestive heart failure and atrial fibrillation).  There is also often a precipitant (infection, trauma, surgery) that triggers the acute thyrotoxicosis.

Clinical pearl: thyrotoxicosis + hypotension
One clinical pearl that Dr. Silver mentioned was the presence of hypotension, in the context of a patient with symptoms and signs of thyrotoxicosis, should make a clinician very worried about true thyroid storm.

The management of thyroid storm includes the following:

1. Symptomatic treatment - In terms of managing symptoms beta blockers are the key component.  But other medications that can be helpful include acetaminophen 500-1000 mg PO q6h prn, which can be given to help manage the pyrexia.  Additionally, benzodiazepenes such as lorazepam can be given if the patient is very anxious and distressed.

Beta blockers such as propranolol can be given orally or intravenously if the patient is truly unstable.  The typical oral dose in thyroid storm is 40 - 80 mg PO q 4 hourly.  Beta-blockers assist with the psychomotor agitation, tachycardia, and also reduce the peripheral conversion of T4 to the more active T3.

2. Blocking the synthesis of new hormone - Thionamide (PTU)  - This class of medication, which mainly consists of Methimazole and PTU (propylthiouracil) blocks the synthesis of new thyroid hormone.  In the acute setting as Dr. Silver mentioned, PTU which has a rapid onset of action as compared with methimazole is the drug of choice.  If the patient is truly in thyroid storm than a loading dose of PTU may be given (1000 mg PO x 1 dose), then it is typically dosed TID in the 200 -400 mg range.

3. Reducing peripheral T4 conversion - Steroids - High dose steroids are often given for a variety of purposes.  The typical doses are 100 mg of hydrocortisone IV TID, or Prednisone 60 mg PO OD.  The duration is usually only for a couple of days.  The purpose of the steroids is to treat concomitant adrenal insufficiency that can be precipitated by the increased metabolism of endogenous cortisol as a result of the thyroid hormone excess.  Also, steroids decrease the peripheral conversion of T4 to T3.

4. Blocking the release of new thyroid hormone - Iodine - Once the patient has received a thionamide to block the synthesis of thyroid hormone, Iodine can be given as this will suppress the release of thyroid hormone from the thyroid gland.  Lugol's solution can be given, and as was mentioned today in morning report, it is usually only used for a short period of time (the initial 48-72 hours).
Other treatments that can be given if iodine is unavailable include Lithium, which also blocks the release of new thyroid hormone from the gland.

5. Treat the underlying precipitant - If is an infection, than appropriate antibiotics should be prescribed.

Lastly, a patient in true thyroid storm needs close monitoring (telemetry, frequent vital signs) and should be monitored in a high acuity setting such as a step-down unit or ICU.  These are also patients where your friendly neighbourhood Endocrinologist should be awoken in the middle of the night to assist in management.

Thanks to Dr. Robert Silver and team 3 for presenting this interesting case!

Hampton, J. Thyroid Gland Disorder Emergencies. 2013.AACN Advanced Critical Care. Volume 24. number 3. pp. 325-332.