Anchors Away

Anchors Away – Peter S. Kibbe, MD FHM 

A fifty-six year old woman is brought to the emergency department because she exhibits confusion.  She is accompanied by her elderly mother who does not see her often but has on the day of her presentation randomly tried to communicate with her and found her confused.  The mother cannot contribute much regarding anything else but knows she has been in good health and knows she does not smoke but thinks she drinks alcohol frequently.  The patient exhibits mild confusion but is fully oriented.  She seems to have memory impairments.  She appears to have no focal neurological complaints.  Her blood alcohol level is 0.08 gm per deciliter and a CT of her head reveals no acute lesions.  She is afebrile and a CBC and basic metabolic panel are unremarkable.  Her symptoms are attributed to ethanol and she is discharged.

En route to her mother’s car she suffers an event involving a fall.  She appears unhurt.  She is returned to the emergency department and admitted with a suspicion of alcohol withdrawal and possible seizure.  She was admitted by a hospitalist and evaluated by a neurologist.

Eight hours later she is found by the rounding hospitalist to have an expressive aphasia and a right homonymous hemianopsia.  She is fully cooperative.  She has a slight fever.  An emergency lumbar puncture reveals lymphocytosis and is positive for herpes simplex antigen.  Appropriate antivirals are administered.  She recovers after seven days.

A forty-two year old woman presents to the emergency department with subacute abdominal pain.  Her urinalysis reveals leukocytes and she is treated for a urinary tract infection and released.  She returns after seven days complaining of abdominal pain, is found on urinalysis to again have leukorrhea and a CT of the abdomen is obtained and is negative.  The hospitalist is called to admit her for a urinary tract infection that has failed outpatient management.  She arrives at the floor.  On questioning she complains of a month of progressive epigastric pain exacerbated by food.  Her physical examination reveals marked tenderness to palpation in the epigastrium.  Upper endoscopy the following morning reveals a large and deep gastric ulceration.

A sixty-one year old nursing assistant presents with right upper quadrant pain of sudden onset following the ingestion of a fatty meal.  She has had two episodes of alcohol related pancreatitis, the last nine months previous, after which she gave up all alcohol ingestion.  A CT of the abdomen reveals a pancreatic cyst, slightly larger than when seen before.  Her serum lipase is normal.  She is admitted for acute pancreatitis.  When she is examined on the floor she reports the pain has improved.  Her examination reveals marked tenderness in the right upper quadrant.  She describes her pain from previous pancreatitis to have been different-epigastric with radiation into the back.  When asked what she thinks is causing her pain she says that she thinks this must be her gall bladder as she had a similar and brief episode two weeks ago after eating fried chicken. Ultrasound of the gall bladder confirms biliary sludge and wall thickening.

“Anchoring” is broadly described as a cognitive bias that occurs in decision making.  It is a cognitive event dependent upon the human tendency to rely too strongly on the first piece of information that is offered in a decision making task.   Each member of the team then reinforces this error, in writing and verbally.   Unless a member of the team is contrarian enough to fully reevaluate the data and repeat investigations, the error anchors the problem into the wrong solutions. So in all three of the above scenarios we see a “first thing” offered— a urinary infection, an alcohol related problem and a pancreatic problem—that anchors the decision making process.   In medical care I would argue it can then propagate through “groupthink” in which members of a group find it easy to accept things that are not necessarily true to minimize their cerebral work and to keep themselves in the majority—to conform.

Anchoring, in my view, is a common threat to patient safety.  It usually is markedly exacerbated by inadequate information gathering, inadequate physical examination, a failure of deductive reasoning, a comfortable emphasis on the importance of laboratory tests or imaging, or a combination of all of the above. 

In the first case, assuming the patient had an alcohol related problem was contrary to her examination and was based on inadequate information. Many people drink alcohol frequently and are not sick from it.  On examination she was muscular, healthy appearing, well kept and not confused but rather having trouble with her speech.  Some people addicted to ethanol do consume enough to give them withdrawal symptoms and are good at hiding it and appear healthy.  But the evidence for this lady having symptoms due to withdrawal were pretty flimsy.  She had no tachycardia or tremor.  She had no stigmata of liver disease.  Her ethanol level was consistent with the ingestion of perhaps two cans of beer.

In the second case there was an inadequate history obtained and the physical examination was superficial.  The diagnosis of urinary infection was made on the basis of a lab test and not on urinary symptoms (asymptomatic bacteruria.)  Going with that handle, that anchor, is so very tempting because it finalizes the work, ends the intellectual chore of actually listening to the patient and hands off the problem.

In the third case there was a failure of “all of the above.” These are the worst. And it is embarrassing when the patient herself ends up telling you, twelve hours after admission, having been examined by two physicians, what the correct diagnosis is.

Groupthink

This is a form of thinking within a group of people in which dysfunctional decision making occurs as a result of the group’s desire for conformity.  Why the group favors conformity can be multi-factorial, but often it involves devotion to the leadership’s thought process.  In this process the group tends to throw out data that conflicts with their view of reality and isolate dissenting voices

This is one of the problems to which medicine is not at all immune.  The opiate addiction crisis is in part to blame on a dysfunctional thought process, to which multiple medical professionals succumbed, and which became a type of thought conformity which went unchallenged in large segments of the the medical establishment.  This was the unproven supposition that people with chronic pain cannot become addicted to opioids.

Anchoring I suspect can also be engendered by the protocols in place to identify stroke and sepsis in hospitalized patients.  When sepsis or stroke alerts are called, the symptoms or signs the patient is exhibiting have now been “anchored.”  Clinicians need to be wary.

Probably the best antidote to the anchoring process in medical thinking is the mature ability to constantly hold a diagnostic assertion in the mind while at the same time subjecting it to doubt.  What one also sees in some very skilled clinicians is a profoundly humble attitude in communication with other professionals, a sincere posture of welcoming critique, a “Please tell me when you think I am wrong” posture in discussing diagnosis and therapy.  This is a humbling job.  “Pride goeth before the fall.”