THE MINI-COG: COGNITIVE IMPAIRMENT AND SURGICAL OUTCOME

Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board-certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.
email rjnov@yahoo.com
phone 650-465-5997
Latest posts by the anesthesia consultant (see all)

What is a Mini-Cog? Most anesthesia professionals have never heard of the Mini-Cog test, but recent evidence shows it can provide important prognostic information on our geriatric patients prior to surgery.

 

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The Mini-Cog™ (© S. Borson, All rights reserved) is a 3-minute screening test for cognitive impairment. The test consists of three steps: Step 1 is Three Word Registration, Step 2 is Clock Drawing, and Step 3 is Three Word Recall Scoring.

STEP 1 (Three Word Registration): To administer the test, you look directly at a patient and say, “Please listen carefully. I am going to say three words that I want you to repeat back to me now and try to remember. The three words are [select one of the list of three words from the versions below]. Please say them for me now.”

If the patient is unable to repeat the words after three attempts, you move on to Step 2.

Version 1: Banana Sunrise Chair

Version 2: Leader Season Table

Version 3: Village Kitchen Baby

Version 4: River Nation Finger

Version 5: Captain Garden Picture

Version 6: Daughter Heaven Mountain

STEP 2 (Clock Drawing): You say: “Next, I want you to draw a clock for me. First, put in all of the numbers where they go.” When that is completed, say: “Now, set the hands to 10 past 11.” You utilize a preprinted circle on a blank page for this exercise. You move to Step 3 if the clock is not complete within three minutes.

STEP 3 (Three Word Recall Scoring): You ask the person to recall the three words you stated in Step 1.

SCORING: Word Recall= ______ (0-3 points), 1 point for each word spontaneously recalled without cueing. Clock Draw= ______ (0 or 2 points). Normal clock = 2 points. A normal clock will have all numbers placed in the correct sequence and approximately correct position (12, 3, 6 and 9 are in anchor positions) with no missing or duplicate numbers. The clock hands are pointing to the 11 and 2 (11:10) positions. Hand length is not scored. Inability or refusal to draw a clock = 0 points.

TOTAL SCORE = Word Recall score + Clock Draw score. Some studies consider a score of 3 or less diagnostic of cognitive impairment, other studies require a score of 2 or less.

 

In the November 2017 issue of Anesthesiology, Culley et al of Harvard utilized the Mini-Cog as a preoperative screening test on 211 patients without a diagnosis of dementia, 65 years of age or older, who were scheduled for an elective total hip or knee replacement. Fifty of 211 (24%) of the patients screened positive for probable cognitive impairment (CI) by a Mini-Cog score of 2 or less. Compared to patients with a score of 3 or greater, the low Mini-Cog scorers were more likely to be discharged to a place other than home (67% vs. 34%), develop postoperative delirium (21% vs. 7%), and have a longer hospital length of stay. Culley concluded that many older elective orthopedic surgical patients have probable cognitive impairment preoperatively, and that this impairment is associated with the development of postoperative complications. The authors suggest that identifying these patients who are at greater risk may allow for the design of interventions to lower complications in this population.

Cognitive impairment (CI) is not dementia, but in all likelihood is a precursor. How common is CI, or the related diagnosis “cognitive impairment, not dementia” (CIND) in America? The incidence of both is higher than you might guess. Plassman et al evaluated for CI in participants in the Aging, Demographic, and Memory Study using a comprehensive in-home assessment. A total of 456 individuals aged 72 years and older who were not demented at baseline were followed for 8 years. An expert panel assigned the diagnosis of normal cognition, CIND, or dementia. The incidence of dementia was 33.3 per 1,000 person-years. The incidence of CIND was 60.4 per 1,000 person-years. An estimated 120.3 individuals per 1,000 person-years progressed from CIND to dementia. Over a 5.9-year period, 3.4 million individuals aged 72 and older in the United States developed dementia, and over this same period almost 4.8 million individuals developed incident CIND. Their conclusions: the incidence of CIND is greater than the incidence of dementia, and that patients with CIND are at a high risk of progressing to dementia.

The value of the Mini-Cog test has been studied in other populations of geriatric patients. Robinson et al studied the preoperative Mini-Cog test in subjects 65 years of age and older, prior to a planned elective operation requiring a postoperative ICU admission. In this study, CI was defined as a Mini-Cog score of 3 or less. Eighty-two out of 186 subjects (44%) had baseline impaired cognition. Compared to those who scored 4 or greater, the CI group had a higher incidence of postoperative complications (41% vs. 24%), a higher incidence of delirium (78% vs. 37%), longer hospital stays (15 ± 14 vs. 9 ± 9 days), higher rate of discharge to an institution (42% vs. 18%), and a higher 6-month mortality rate (13% vs. 5%).

Patel et al studied the Mini-Cog test on 720 consecutive patients prior to discharge during hospitalization for heart failure. A Mini-Cog score of 2 or less was considered abnormal. The prevalence of CI was high (23%). In the 6 months following hospitalization, 342 of the 72 patients (48%) were readmitted, and 24 (3%) died. A poor Mini-Cog performance was identified as the most important predictor of readmission or death among 55 variables studied.

At Stanford our department is titled the Department of Anesthesiology, Perioperative and Pain Medicine. Perioperative medicine includes preoperative evaluation. The concept of a Preoperative Anesthesia Clinic originated with Dr. Steve Fischer at Stanford. As a double-boarded anesthesiologist and internal medicine doctor, I’ve honed my skills in the preoperative evaluation of the geriatric patient. Up to the present I have not utilized the Mini-Cog test in my preoperative evaluation.

Should the future preoperative evaluation of geriatric surgical patients include a Mini-Cog test?

Perhaps.

The American College of Surgeons and the American Geriatrics Society recently published guidelines recommending the preoperative screening of older surgical patients with a tool such as the Mini-Cog. These are recommendations, not mandates, and time will tell how prevalent the Mini-Cog becomes in the geriatric anesthesia preoperative workup. It’s unlikely that patients will be denied surgery for borderline or low preoperative Mini-Cog scores, but the potential for improving postoperative outcomes in the low scorers presents a challenge for the entire perioperative community of anesthesiologists, surgeons, intensivists, and nurses.

Keep your eyes open for further research regarding the value of the preoperative Mini-Cog test. And as you age, you might choose to rehearse your retention of the three-word lists above, and practice drawing clocks that read 11:10.   🙂

 

The most popular posts for laypeople on The Anesthesia Consultant include:

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LEARN MORE ABOUT RICK NOVAK’S FICTION WRITING AT RICK NOVAK.COM BY CLICKING ON THE PICTURE BELOW:

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PREANESTHESIA CLEARANCE: TWO QUESTIONS FOR PRIMARY CARE DOCTORS

Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board-certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.
email rjnov@yahoo.com
phone 650-465-5997
Latest posts by the anesthesia consultant (see all)

Many patients require preoperative clearance prior to surgery, especially patients with significant medical problems or at extremes of age. Preanesthesia evaluation reduces surgical and medical complications. What two questions for primary care doctors summarize the desired important information in preoperative surgical clearance?

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Some health care systems run preoperative anesthesia clinics, where anesthesia professionals evaluate these patients prior to surgery. Such clinics can increase operating room efficiency and decrease day-of-surgery cancellations and delays, and are especially important prior to major inpatient surgeries such as brain surgeries, chest surgeries, abdominal surgeries and major transplants. In many health care systems there are no anesthesia clinics, and primary care doctors (internal medicine specialists, family practitioners, or pediatricians) do the preoperative assessments.

The surgeon may request the clearance or an anesthesiologist may request the clearance, but it will ultimately be the anesthesiologist who must care for the heart, lungs, brain, and blood pressure during the surgery and in the recovery room after the surgery.

Let’s choose an illustrative example. A 60-year-old man is scheduled to have a laparoscopic gallbladder removal (cholecystectomy). He takes lisinopril for hypertension and metformin for diabetes. He weighs 240 pounds, has a Body Mass Index of 38, and never exercises. What do anesthesiologists want to see in the internal medicine preoperative clearance consult?

We want to know the answer to two questions:

  1. Does the patient require any additional diagnostic workup prior to the surgery?
  2. Does the patient require any additional therapeutic changes prior to the surgery?

I’m Stanford-trained and board-certified in both internal medicine and anesthesiology, so I’m uniquely qualified to discuss this topic. Let’s look at what the process of an internal medicine preoperative consult looks like.

Let’s assume the internist has not seen the patient in the past year. The patient will be seen at the internist’s office, where the internist does a history and a physical, followed by an assessment and plan. The history includes a documentation of the past medical history, a review of current symptoms, a list of medications, allergies, past surgical history and family history. The physical exam includes the height, weight, vital signs, and documentation of any abnormal findings on exam of the entire body. The internist’s assessment will include a list of medical problems and a plan for each problem. For the patient above, the problem list would include:

  1. Hypertension
  2. Type 2 diabetes
  3. Obesity
  4. Sedentary lifestyle
  5. Preoperative assessment for upcoming general anesthesia for gallstones

An assessment and plan for each medical problem would be listed as follows:

  1. BP= 140/85 today. Plan: currently adequately controlled. Continue lisinopril.
  2. Plan: Check fasting glucose and hemoglobin A1c. Continue metformin.
  3. Plan: Weight loss counseling and consult with dietician.
  4. Sedentary Lifestyle. Plan: Advised initiation of exercise program.
  5. Preoperative assessment. Plan: cleared for general anesthesia providing ECG and labs are normal.

The labs are ordered, and the results accompany the history and physical. All the lab tests are normal. The ECG is abnormal, and shows diffuse ST wave abnormalities suspicious for ischemia (inadequate blood flow to the heart muscle). At this point the primary care physician can answer the two questions above:

  1. Does the patient require any additional diagnostic workup prior to the surgery? Answer: Yes. The patient requires referral to a cardiologist for workup of the abnormal ECG, especially in context of his sedentary lifestyle and risk factors of hypertension and diabetes.
  2. Does the patient require any additional therapeutic changes prior to the surgery? Answer: Dependent on the cardiologist’s assessment.

The surgery is delayed pending the cardiologist assessment. The cardiologist sees the patient, and recommends an exercise stress echocardiographic. The test is done, and is abnormal—the patient has abnormal decreased movement of the left anterior wall of his heart with exercise. Because of this abnormality, the cardiologist recommends a cardiac catheterization. The cardiac cath is done, and the patient has a 90% narrowing of his left anterior descending coronary artery. The cardiologist places a stent across this narrowing, and the patient is discharged home.

Because of the primary care doctor’s work, the patient had the necessary diagnostic tests done (blood work, ECG, and referral to cardiology), and the patient had a necessary therapeutic intervention done (a coronary stent). The gall bladder surgery is scheduled for one month hence.

Let’s discuss what a primary care doctor’s not should NOT be. The primary care doctor should not recommend what form of anesthesia is safe, e.g. “medically cleared for spinal anesthesia,” or “medically cleared for local anesthesia plus sedation.,” or “medically cleared for regional block anesthesia.” The primary care doctor should not recommend what drugs are safe to use. The primary care doctor should not recommend where the surgery should or should not be done, e.g. in a hospital, a surgery center, or in a doctor’s office. The primary care doctor should not estimate the percentage of survival or morbidity for the scheduled procedure.

Primary care doctors are very smart and highly trained professionals, but primary care doctors don’t work in operating rooms. They don’t know which anesthetic technique to recommend, which drugs to utilize, or the different strengths and weaknesses of different anesthetizing locations. What they do know is the outpatient condition of their patient.

Anesthesiologists need the answers to #1 and #2 above. If you’re an anesthesiologist, you now know exactly what questions to ask. If you’re a patient about to undergo surgery, you now know how important the preoperative medical assessment is to your anesthesiologist.

 

The most popular posts for laypeople on The Anesthesia Consultant include:

How Long Will It Take To Wake Up From General Anesthesia?

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The most popular posts for anesthesia professionals on The Anesthesia Consultant  include:

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LEARN MORE ABOUT RICK NOVAK’S FICTION WRITING AT RICK NOVAK.COM BY CLICKING ON THE PICTURE BELOW:

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SHOULD YOU CANCEL SURGERY FOR A LOW POTASSIUM LEVEL OF 3.4 mEq/L?

Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board-certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.
email rjnov@yahoo.com
phone 650-465-5997
Latest posts by the anesthesia consultant (see all)

Clinical Case of the Month:  You’re medical director for a busy outpatient surgery center.  An RN routinely does the preoperative screening by telephoning each patient two days prior to surgery.  The RN pages you with this question:  A 48-year-old patient scheduled for anterior cruciate ligament (ACL) reconstruction surgery takes hydrochlorothiazide for hypertension, and has not had electrolytes checked for six months.  His last labs show a low potassium = 3.4 mEq/L.  The patient is asymptomatic except for knee pain. The nurse asks you whether this patient needs to have his potassium rechecked now, before surgery.  What do you do?

Discussion: Pre-op evaluation will never be the topic of a Hollywood thriller — you’ll never see Tom Cruise or Brad Pitt rubbing their temples worrying about whether they need to recheck the electrolytes.  But for you and me, it’s a question worth discussing. How important is it to diagnose hypokalemia in this asymptomatic patient on chronic diuretic therapy?  If the K=3.0 mEq/L, will you cancel the surgery?  What about if the K=2.9 mEq/L?  Experienced anesthesiologists know standards of care for their specialty, and also develop a gut impression about which patients are prepared for surgery, and which ones are not.  Do you sense this patient is at risk for sudden death or a cardiac arrhythmia?  Let’s examine this question.

First off, why didn’t you see this patient in your pre-op clinic?  The answer is because you won’t find the Stanford model of a well-staffed Pre-Anesthesia Clinic in the private practice community.  The Pre-Anesthesia Clinic is important at Stanford because many patients suffer from significant medical comorbidities, and because of the invasive nature of many of the inpatient surgeries.  In a community practice with healthier patients and less invasive procedures, there is neither the money nor the need to physically meet and examine every patient several days prior to surgery.  Adam Smith’s economic dictum of the invisible hand pertains to clinical medicine as well — anesthesiologists are paid to give anesthetics.  Neither insurers nor Medicare will reimburse you for routine pre-operative clinic encounters with patients.

In 2002, the American Society of Anesthesia published Practice Advisory for Preanesthesia Evaluation:  A Report by the American Society of Anesthesiologists Task Force on Preanesthesia Evaluation. Their recommendations for the timing of preanesthesia evaluation differ, depending on the severity of disease and also on the surgical invasiveness.  Our patient’s surgery involves a non-severe comorbidity (well-controlled hypertension) and a non-invasive surgery (knee arthroscopy).  For patients such as this, the ASA Practice Advisory states, “preoperative assessment may be done on or before the day of surgery. “ In our community outpatient practice in Palo Alto, a surgery-center RN calls the patient two days prior to surgery to ask pertinent questions.  This telephone call helps avoid day-of-surgery surprises (e.g. patients still on aspirin, patients with undiagnosed chest pain or dyspnea).  The physical evaluation by the anesthesia attending occurs on the day of surgery.

Outpatient surgery centers rarely have the ability to do lab tests other than blood glucose measurements or a 12-lead ECG.  Tests such as the measurement of electrolyte concentrations need to be done at an outside lab, at least one day prior to surgery.  Regarding preanesthesia serum chemistries (i.e., potassium, glucose, sodium, renal and liver function studies), the ASA Practice Advisory gives no specific recommendation to check preoperative electrolytes during chronic diuretic therapy.  The recommendation on checking pre-op electrolytes states  “Clinical characteristics to consider before ordering such tests include likely perioperative therapies, endocrine disorders, risk of renal and liver dysfunction, and use of certain medications or alternative therapies.”

Might “perioperative therapies” include potassium replacement? Consider this: potassium is predominantly an intracellular ion.  Per Miller’s Anesthesia, “Only 2% of total-body potassium is stored in plasma. . . .  a 20% to 25% change in potassium levels in plasma could represent a change in total-body potassium of 1000 mEq or more if the change were chronic or as little as 10 to 20 mEq if the change were acute. . . . Chronic changes are relatively well tolerated because of the equilibration of serum and intracellular stores that takes place over time to return the resting membrane potential of excitable cells to nearly normal levels.” (Miller’s Anesthesia, 2005, pp.1105-6)

The same textbook states, “Retrospective epidemiologic studies attribute significant risk to the administration of potassium (even chronic oral administration).  In one study, 1910 of 16,048 consecutive hospitalized patients were given oral potassium supplements.  Of these 1910 patients, hyperkalemia contributed to death in 7, and the incidence of complications of potassium therapy was 1 in 250.” (Miller’s Anesthesia, 2005, p. 1107).

Given this information, what should we do?

Here’s the answer: Per Miller’s Anesthesia, p. 1107, “As a rule, all patients undergoing elective surgery should have normal serum potassium levels.  However, we do not recommend delaying surgery if the serum potassium level is above 2.8 mEq/L or below 5.9 mEq/L, if the cause of the potassium imbalance is known, and if the patient is in otherwise optimal condition.”

The same textbook points out an additional problem in ordering lab tests: “the failure to pursue an abnormality appropriately poses a greater risk of medicolegal liability than does failure to detect that abnormality. In this way, extra testing increases the medicolegal risk to physicians.” (Miller’s Anesthesia, 2005, p. 945)

Regarding the timing of lab testing, the ASA Practice Advisory on Preanesthesia Evaluation states “test results obtained from the medical record within 6 months of surgery are generally acceptable if the patient’s medical history has not changed substantially. More recent test results may be desirable when the medical history has changed, or when test results may play a role in the selection of a specific anesthetic technique (e.g., regional anesthesia in the setting of anticoagulation therapy.)”

For all the reasons stated above, you tell the RN that you won’t recheck the potassium lab value for this patient, and you won’t delay or cancel the ACL surgery.  The surgery is completed two days later, without complication.  Your two clients, the patient and the surgeon, are both happy, and you’ve practiced sound, evidence-based medicine.

For further details on the management of hypokalemia and hyperkalemia before, during, and after surgery, see the chapter I wrote entitled Disorders of Potassium Balance, in Complications in Anesthesia, 3rd Edition, 2017, edited by Lee Fleisher and Stanley Rosenbaum, Elsevier Press, Philadelphia.

 

The most popular posts for laypeople on The Anesthesia Consultant include:

How Long Will It Take To Wake Up From General Anesthesia?

Why Did Take Me So Long To Wake From General Anesthesia?

Will I Have a Breathing Tube During Anesthesia?

What Are the Common Anesthesia Medications?

How Safe is Anesthesia in the 21st Century?

Will I Be Nauseated After General Anesthesia?

What Are the Anesthesia Risks For Children?

 

The most popular posts for anesthesia professionals on The Anesthesia Consultant  include:

10 Trends for the Future of Anesthesia

Should You Cancel Anesthesia for a Potassium Level of 3.6?

12 Important Things to Know as You Near the End of Your Anesthesia Training

Should You Cancel Surgery For a Blood Pressure = 178/108?

Advice For Passing the Anesthesia Oral Board Exams

What Personal Characteristics are Necessary to Become a Successful Anesthesiologist?

 

 

Learn more about Rick Novak’s fiction writing at rick novak.com by clicking on the picture below:

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