Fainting , Diabetes , High blood pressure Sleep Apnea and the Vagus nerve

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 Vagus nerve 
The vagus nerve is the longest most wide spread nerve in our body. This nerve supplies fibers to every organ except the adrenal gland.  Most of these fibers (80 % ) carry information towards the brain and some of these fibers are very sensitive to low blood glucose  and low oxygen levels resulting in a variety of symptoms .

 Common symptoms often associated with the vagus nerve.
   Heart rate - stimulation of the vagus nerve causes slowing of the heart rate and
                        severe stimulation can cause conduction blocks in the heart.
                               The patient discussed in a previous post had transient blocks in the electrical connection between the
                                upper and lower parts of his heart. 
    Sweating  -  especially facial sweating
   Gastrointestinal - Nausea

The patient discussed in a previous post had all of the above symptoms and testing revealed low oxygen levels of 78 %.  Click on the link below to review the case.

•                                Sleep Apnea , A mix of seemingly unrelated symptom...

The patient above also had hypertension and pre-diabetes and his cardiology work up revealed episodes of slow heart rates including transient heart blocks occuring at night. Blood oxygen levels revealed 98 episodes of anoxia ( oxygen levels dropping to 78 %)  on the night tested. Normal oxygen levels are 95 to 99 % and values below 90% are considered abnormal.

He was diagnosed and treated for Obstructive Sleep Apnea and his oxygen levels and his symptoms have almost completely resolved with CPAP treatment.  He still has occasional mild symptoms of transient nausea and sweating that can be traced back to  an increased number of  night time episodes of apnea  3 to 4 /hour . ( normal is less than 5 ) the night before. The cause for the periodic increase in apnea ( usually for 2 nights ) has not yet been determined.  In addition , his BP is usually increased for 3 to 4 days during and after these periodic episodes.  His BP is nomally controlled  to 130 +- / 75 + - with a diuretic every other day. His Pre- diabetes has not progressed. .

Have Fun , Be Smart and do not overlook sleep apnea 
David Calder,MD


   
                       
                       
                       

Vasovagal Syndrome ( fainting) in middle age and older adults association with a common correctable health problem

Vasovagal syndrome ( fainting ) is more common in young adults and then the incidence peaks again in   the 60 and 70 + age group.

Symptoms :
 Random periodic episodes of unusual nausea , facial sweating ,  pale face ,urge to sit down and has occasional syncopal  episodes. The nausea is vague and just somehow different . The symptoms can occur any time during the day and is not related to activity , body position or food intake.

The onset of these symptoms in middle age and older people can be associated with what common correctable health problem ?

Hint : read the 2 previous post for more information.

•                                Sleep Apnea , A mix of seemingly unrelated symptom...
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•                                 treating high blood pressure without medication si...
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•     Have Fun , Be Smart and talk to your doctor about the onset of new unusual symptoms
•     David Calder, MD
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• Tomorrow  some interesting insight into the symptoms associated with  sleep apnea and its unusual symptoms
  
  

Why is my finger stick glucose often different that a laboratory glucose test ?

Why is my finger stick often different that the laboratory glucose test?

Is there a difference between whole blood and plasma glucose test results ?

   We all put a lot of faith in our home glucose testing equipment and feel comfortable making management decisions based on the test results.  However, have you ever wondered why your finger stick capillary test is often different than the venous glucose test done in a laboratory. There are a number of variables effecting your glucose test results.

   The source of the blood sample ( arterial , capillary  or venous ) and how the blood was processed all make a difference .  Whole blood is usually removed from a vein in our arm and then put into a centrifuge and separated into plasma and red blood cells. The glucose test is then done on the plasma component of the blood. Whole blood can also be allowed to clot which separates the blood into red blood cells and serum.  Your finger stick test is measuring whole blood glucose taken from capillaries in your finger and done on a machine with it's own built in error rate. The last time I checked, meters  are  required to have an error rate of < 20% at glucose levels of 30 to 400 mg/dl.

 From my own personal experience in the hospital and office , where I frequently compared finger stick results with hospital lab. results , I believe the error rate on most meters is small and not a major issue.

The source of the blood effects the results. Arterial blood is about 5% higher than capillary blood and 10% higher than venous blood. You are not likely to be using arterial blood but you will be comparing capillary blood ( finger stick sample) to venous blood that is usually taken from your arm by a lab. Tech. This means ,that if you did a fingerstick test( capillary blood )at the same time as a laboratory test( venous blood) , your result may be a little higher than the lab result by about 5%
Their is another interesting variable to be aware of. Your glucose meter reads” whole blood ” which is about 10 to 15 % lower than “plasma ” used by the lab .. I believed that this was a good thing when I was following hospital patients on continuous intravenous insulin infusion because the hourly finger stick test were a little higher ( capillary whole blood) and made the lab ( venous plasma )and bedside test have a little better correlation .Then the meter builders decide to convert the whole blood results into a plasma-calibrated result. For the doctor this change resulted in higher bedside result and more concern that we may miss low test results.. I had to adapt to the change.
Summary:
So this is probable a lot more than you wanted to know but it may help you understand why your home test may not match the lab. results. In general our home meter are wonderful machines that have dramatically improve our lives..

Have fun , Be smart and test your blood glucose frequently and learn how to use the results to make decisions in in your daily diabetes management decisions.
David Calder, MD