Hyponatremia - no it's Hyperhydroemia

CLINICAL PEARLS WHEN TREATING HYPONATERMIA?

1. In patients on diuretics, the fractional excretion of urea can be used to help determine if patient is hypovolemic. FeUrea= (Uurea/Purea)/(UCr/Pcr)
FeUrea <35% suggests prerenal state.

2. Before accusing someone of having SIADH, you must check TSH and adrenal function (ACTH stim).

3. Acute recognition of a chronic problem (chronic hyponatremia) does not require acute treatment.

4. To prevent overly rapid correction of hyponatremia, consider the role for DDAVP (often given as 1-2mcg SC/IV). If you do correct too quickly (want to correct 0.5 mmol/h at the absolute most) also consider giving D5W in addition to DDAVP - see the article below.

5. If volume repletion is required, give fluid that is isotonic to the patient by using a combination of NS and D5W.

6. Attach the foley catheter to the IV (figuratively) - be sure to monitor urine osm and output - and consider calculating a tonicity balance

Extras:
When seeing hyponatremia in the ER:

First rule out acute hyponatremia that needs acute correction.

Recheck the lytes as they were often done a while ago and the patient has possibly received intravenous fluids that may have significantly altered the sodium concentration - especially if the stimulus (often ECF volume depletion) for ADH secretion has been removed. Following the urine output may help to identify this (although recording can be an issue outside of the ICU) as a brisk, dilute diuresis can be bad sign.



An article on DDAVP to prevent rapid correction is posted here.

Familial Mediterranean Fever

Doctor, There's a Hole in my Heart!?

An interesting article published by one of our staff and residents on morning report can be found here.

A prior blog on the causes of platypnea and orthodeoxia can be found here.

Review of PFO formation:

• The endocardial cushions fuse, separating the heart into R and L sides.

• Early in utero the septum primum grows and fuses with the endocardial cushion, closing the formaen primum, however perorations have developed in the septum primum to fuse, forming the foramen secundum (still allowing right to left shunting)

• A second membrane, the septum secundum, grows on the right atrial side of the septum primum. The septum secundum overlaps the foramen secundum, forming an incomplete septal partition that becomes the foramen ovale. The remaining septum primum forms a flap-like valve over the foramen ovale.
• After birth, normal circulation is established (left sided pressures>right sided) and the flap fuses in 75% of people by age 2. The remainder have a PFO.
• The PFO is completed covered, but not sealed and shunting can occur if there is a reversal in intracardiac pressures (i.e. right to left shunt).
  
• If an open communication exits (no flap) this is an ASD.
  

In studies, PFO prevalance is as high as 25%

A debate on PFO closure (with respect to cryptogenic stroke) can be found in these two Circulation articles: Close v. Don't Close (or at least do an RCT).

SIGNOVER SAFETY

An effective handover is critical to safe and efficient patient care.

The mneumonic "SIGNOUT?" was developed as part of a signover curriculum discussed in this article.

S - Is the patient sick? Stable? Code Status?
I- ID
G - General Hospital Course
N - New events of the day
O - Overall clinical condition
U - Upcoming possibilities (those that can reasonably anticipated) with plan/rationale
T - Tasks to complete overnight (explicit instructions) and rationale
? - Any questions?