Sodium is an often-overlooked electrolyte that can cause life-threatening injuries to patients after surgery.
Our bodies maintain a fragile balance of serum sodium in the bloodstream. Most hospital laboratories consider a normal serum sodium level to be 135–145 mEq/L. A value below that range is called hyponatremia. The patient has severe hyponatremia with the lab value of less than 120 mEq/L.
Signs and symptoms of hyponatremia
When a person develops hyponatremia, common symptoms include nausea, vomiting, and headache. These symptoms, of course, are consistent with all kinds of medical conditions. On top of these, many medical experts consider the telltale sign of potential hyponatremia to be altered mental status or confusion.
This is one of the reasons why I think it is important for hospitalized patients to have a family member or friend with them during their admission. Even excellent doctors and nurses may have a hard time identifying the earliest signs of a change in the patient’s baseline behavior. For family and friends, though, it is easy to notice a change in behavior that’s more than the expected post-operative pain. It’s also important to bring this to the attention of the healthcare providers as soon as possible.
Why low sodium levels are dangerous
The critical serum sodium balance in the body influences the volume of cells. Low sodium levels (hypotonicity) cause cells to maintain water and swell. High sodium levels (hypertonicity) cause cells to release water and shrink.
If you’ve ever gone through surgery or known someone who has, you understand that the body goes through an intense amount of stress because of the procedure itself. Because of the surgical stress, it’s normal for patients to have elevated levels of a hormone called antidiuretic hormone (ADH, or vasopressin) for a few days after surgery. ADH is a hormone that’s released by the pituitary gland to help maintain osmotic/fluid/water balance, which includes electrolyte levels, blood pressure and, of course, sodium levels.
Among other things, high levels of ADH can cause cells to swell by altering the fluid-electrolyte balance, including sodium. In the brain, this can be extremely dangerous because the brain is surrounded by the cranial cavity, which has limited capacity to accommodate the swollen cells. If brain swelling continues without treatment, the brain can herniated or squeeze out the only open space in the cranial cavity, the foramen magnum, which is a hole in the back bottom of the head where the spinal cord connects to the brain.
When the brain herniates, it’s often fatal. Even survivors, though, are usually left with severe, permanent brain injuries.
The role of IV fluids
To recap what we’ve discussed so far:
• Any surgery causes stress on the body.
• After any surgery, it’s common for ADH levels to rise for a few days.
• Elevated ADH levels can cause lower serum sodium levels and swelling of cells, including brain cells.
Medical experts recognize that any surgery can place a patient at an increased risk for hyponatremia (low serum sodium levels) and cellular swelling, including brain cells. For any surgery involving the brain, there is an even higher risk.
Over the last few decades, there’s been a rapid increase in our understanding of the importance of the type of intravenous (IV) fluids that should be given to post-operative patients. In most situations, and in particular for patients who have gone through a brain surgery procedure, internal medicine experts recommend administering hypertonic saline, which works to pull water/fluid content from brain cells and protect against swelling.
Despite this knowledge, some hospitals and physicians continue making the mistake of administering IV hypotonic saline to post-operative patients, which has the opposite effect of causing cells to swell. Other hospitals give post-operative patients isotonic saline by IV, which doesn’t alter the fluid-electrolyte balance, but leaves the patient at risk for brain cell swelling because of the normal post-operative release of ADH.
What's the big picture on hyponatremia?
It’s easy for all of this to sound like gobbledygook. The take-home message is to be aware of an increased risk of brain swelling after surgery. This is particularly true after the patient is undergoing a brain surgery or has had any trauma to the head.
Additionally, despite advances in this area, many hospitals and healthcare providers continue to disparage post-operative IV fluids. That’s why attentive and vigilant family and friends will speak up when there hospitalized loved ones have a change in behavior. This can be the first sign of hyponatremia.
I’ve handled many cases where hospitals and surgeons have provided life-saving operating room services to patients, only to lead to death or permanent disability of the patient’s by not carefully monitoring post-operative sodium levels. It’s easy and inexpensive to monitor but seems to fall through the cracks over and over again.
My next article will be about the problem of over-correcting hyponatremia too quickly. The best chance for a patient to recover from the situation is for the medical and nursing team to recognize the possibility of hyponatremia quickly. With a prompt diagnosis and appropriate gradual treatment, this condition can be cured.
If you or someone you care for has been seriously injured because of poor hyponatremia, surgical, or medical care, then contact an experienced top-rated Houston, Texas medical malpractice lawyer for help in evaluating your potential case.