Preoperative Evaluation of the Patient

Question 1

The proper pre-op should include all of the following

Answer 1

An interview

A full physical examination

Diagnostics

Scoring of Risk

Plan for anesthesia

Question 2

FITNESS FOR ANESTHESIA

Answer 2

The clinician must try to avoid any possible complications before they become life threatening

To that end the clinician will see each surgical candidate long before the procedure is scheduled

The very ill patient will often fair poorly under general anesthesia, as well as the surgery

Poor candidate may not always exclude the pt from getting the procedure done

Question 3

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

An E is added to any of the category

Answer 3

*Adding E to any of the above categories denotes an emergency

Question 4

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 6

Answer 4

Brain Dead

Question 5

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 5

Answer 5

A moribund pt who is expected to die within 24 hours if they do not get the surgery

Eg.Ruptured AAA, PTE, Increased ICP

Question 6

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 4

Answer 6

A pt with severe systemic disease that is a constant threat to their life

Eg.CHF, Renal or Hepatic failure, Unstable angina

Question 7

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 3

Answer 7

A pt. with a severe systemic disease

Eg. Uncontrolled hypertension, DM with vascular issues, previous MI, COPD

Question 8

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 2

Answer 8

A pt with a mild systemic disease

Eg. Controlled hypertesion, diabetes

Question 9

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION SYSTEM

ASA 1

Answer 9

Fit and Healthy Person

Question 10

ANESTHETIC RISK-Drug Regime

Answer 10

Any drug regimens they are on, may contraindicate certain agents or procedures

Drug therapies will/can interact negatively with the agents used.

This may require cessation of therapies which will further complicate their illness

For all purposes the anesthesiologist will want them to continue their medications going into the surgery

Sometimes when a pt is admitted into the ICU the dr will stop all their drugs and then only add back the drugs that they think are needed and this can be helpful when they are preparing for a surgery

Question 11

ANESTHETIC RISK-Diseases

Answer 11

Any disease state alters homeostasis and increases the risk of side effects and bad outcomes

Systemic disease will alter uptake, distribution and elimination of the anesthetic agents.

Systemic illness can interfere with anesthetic procedures

Eg. Intubation, monitoring etc.

Question 12

RISK FACTORS

AGE

Answer 12

The very young and the very old have increased risk of negative outcomes from both surgery and general anesthesia.

Often regular doses are too much and elimination via normal pathways can be less efficient, therefore agents will have prolonged effect.

Recovery can be complicated and drugs hard to reverse.

Question 13

Ischemic Heart Disease

What Kind of Monitoring Will these Pt Need

Answer 13

These pts will need invasive hemodynamic monitoring, (ie. Swan-Ganz), so circulatory dynamics can be monitored and adjusted.

Question 14

Ischemic Heart Disease

What Are Some Things You Are Trying To Prevent

Answer 14

Tachycardia, hypertension, LV failure etc. can be avoided with the appropriate therapy.

Question 15

Ischemic Heart Disease

Drug Therapies

Answer 15

Existing drug therapy needs to be “tuned-up” to ensure optimum therapy and problem avoidance

Question 16

Ischemic Heart Disease

Pt History and Preoperative Evaulation What Are The Main Things You Are Looking For

Answer 16

Cardiac Reserve

Angina

Prior Myocaridal Infarction

Current Medications

Question 17

Ischemic Heart Disease

Cardiac Reserve

Answer 17

The work the heart is able to perform beyond that required under the ordinary circumstances of daily life

Limited exercise tolerance in the absence of pulmonary disease is the most striking evidence of decreased cardiac reserve

Question 18

Ischemic Heart Disease

Angina

Answer 18

Myocardial ischemia caused by an imbalance between myocardial blood supply and oxygen demand

The heart rate and systolic BP at which angina or evidence of ischemia is indicated on the ECG are useful preoperative information

Increased RR is more likely than hypertension to produce sings of ischemia (Tachycardia increases myocardial oxygen demand without increasing coronary perfusion).

Question 19

Ischemic Heart Disease

Prior Myocardial Infarction

Answer 19

The incidence of a second myocardial infarction in the perioperative setting is related to the time elapsed since the previous infarction. The less time between the previous MI and Sx, the increased risk of another MI. The incidence of perioperative MI does not stabilize at 5-6% until six months after the prior MI

Question 20

Ischemic Heart Disease

Current Medications

Answer 20

Most likely drugs include B-antagonists, nitrates, Ca2+ channel blockers, ACE inhibitors, statins, diuretics, and platelet inhibitors.

Patients on B-Blockers should be monitored closely throughout the perioperative period

Discontinuation of the above mentioned drugs in the perioperative period can increase risk of perioperative morbidity and mortality and should not be discontinued.

Question 21

Ischemic Heart Disease

ECG

Answer 21

A preoperative resting 12 lead ECG is recommended

Question 22

Risk Stratification Vs Risk Reduction

Answer 22

The approach of prescribing various invasive procedures vs careful history taking, assessment and prophylactic medical therapy

Question 23

PRIMARY HYPERTENSION

Answer 23

Existing drug regimens need to be optimized. Some diuretics can cause hypokalemia, (low serum potassium); weakness, rapid pulse, N&V, peripheral tingling.

Those with uncontrolled hypertension have a greater risk for hypotension during the procedure

Question 24

Primary Hypertension

Answer 24

Determination of the BP control and review of antihypertensive medications

Medications should be continued throughout the perioperative period

Consider the administration of prophylactic anti-ischemic therapy in (perioperative B-Blockers)

Preoperative treatment should occur because of the incidence of hypotension and the evidence of myocardial ischemia on the ECG during the maintenance of anesthesia is increased in patients who remain hypertensive before the induction of anesthesia

Question 25

COPD

Answer 25

Existing V/Q mismatch problems can be further compromised by anesthetic agents.

Some agents are potent respiratory depressants.

Retention of secretions post-operatively.

Regional vs general anesthesia.

Question 26

COPD Preoperative Evaluation

CXR

Answer 26

• Right Ventricular Dysfunction
  
  • Occurs in 50% patients with severe COPD
  • Cor pulmonale occurs in 70% of COPD patients with an FEV1 < 0.6L
• Bullae (big balloon like area of the lung which is destroyed alveoli)
  
  • Be aware of potential ventilation issues in perioperative period

Question 27

COPD Preoperative Evaluation

Spirometry

Answer 27

Flow limitation that is associated with COPD can lead to the development of autoPEEP during the perioperative period

Severely flow limited patients are at risk of hemodynamic instability and collapse due dynamic hyperinflation and subsequent decreased or obliterated pulmonary blood flow

Question 28

COPD Preoperative Evaluation

ABG

Answer 28

ABGs provide baseline for long and intensive operations and provide the health care team with a potential prognosis of perioperative and post operative care

Oxygen saturations and ABGs should be monitored throughout the procedure due to lack of oxygen reserve and potential ineffective ventilation

Question 29

Liver Disease

Answer 29

The liver controls most important pathways of drug elimination. Hepatocytes, production of pseudo-cholinesterase, maintenance of the albumin/globulin ratios are all functions of the liver that will effect drug efficacy and reversal.

Bio-chemical abnormalities, hematologic abnormalities, agent specific hepatotoxicity.

Question 30

PREOPERATIVE EVALUATION OF LIVER DISEASE:

Answer 30

Liver function Tests detect the presence of liver disease and allows the health care team to prepare for common and potential complications in both perioperative and postoperative periods.

Morbidity and mortality rates after elective operations are more frequent in patients with preexisting cirrhosis of the liver

It may take additional stressors, such as anesthesia and surgery, to reveal the underlying liver disease. In adequate hepatocyte function during anesthesia and surgery can be manifested as metabolic acidosis intraoperatively

Question 31

Complications could occur due to Liver Disease?

Answer 31

Drug Binding and Metabolism

Acites (Secondary Complication)

Hepatopulmonary syndrome (Pulmonary vasodilation causing increased V/Q mismatch)

Question 32

Chronic Renal Insufficiency

Answer 32

Proper renal clearance of drugs or metabolites is key to maintaining homeostasis. All the regular functions of the kidneys, (acid/base control, blood cleaning etc.) need to be factored in.

Hypertension, anemia, fluid & electrolyte balance, agent specific nephro-toxicity etc.

Question 33

Renal Function Test

Answer 33

Renal Function Tests are used to highlight specific renal deficiencies

Note: Significant renal disease can exist with normal lab values, even with up to 50% or more decrease in renal function (This should emphasize the importance of past medical history taking and reviewing patient health care charts)

Question 34

Diabetes Mellitus

Answer 34

Generalized arteriosclerosis, nephropathy, neuropathy, retinopathy etc. are potential complications to the 2% of the general POP that has insulin dependent DM.

Gluconeogenesis, in response to the stress of surgery can be counterbalanced by the relative hypoglycemia of pre-operative fasting. Hypoglycemia can be masked by agents.

When the body is placed under stress it will produce glucose in the body

Question 35

ADRENAL INSUFFICIENCY

Answer 35

Although some pts may have adrenal suppression caused by disease, many more will have it because of steroid therapy. Low cortisol levels may decrease SVR and C.O.

Surgery can cause dramatic increases in plasma cortisol levels. Typically these increases are returned to normal by the third post-op day.

Question 36

Questions to Ask About Anemia

Answer 36

Is the anemia chronic or acute?

Is the anemia related to the reason for surgery? (hemo-dilution from fluid resuscitation, chronic or acute blood loss, hepatic or renal disease).

Is the anemia causing symptoms (dyspnea, angina).

Is the surgery immediately necessary?

Is the anemia severe enough to require blood replacement?

Decisions may include EPO therapy.

Question 37

ARTHRITIS

Answer 37

3% of the POP is affected. 10% of those are severely disabled. Women predominate in the peripheral joint effecting, rheumatoid variety. Men predominate in the axial joint effecting ‘Ankylosing Spondylitis’

Both may have anemia, neural, or fibrotic changes.

Long term steroid use, positioning and intubation.

Question 38

TRAUMA

Answer 38

Broken bones, damaged tissues (­serum potassium), hemorrhage, circulatory collapse etc. etc.

Burns: High serum potassium precludes Succs; circulatory collapse, etc.

For things like burn succ in contraindicated

Question 39

SUBSTANCE ABUSE

Answer 39

The major substance abuse problem in North America is chronic alcoholism.

Alcoholism causes liver disease (elimination), cardiomyopathies (cardiac insufficiency), encephalopathy (impaired CNS synaptic function).

Acute intoxication is a major depressant therefore induction and inhaled agents will have a cumulative effect. Risk of catastrophic hypotension.

Gastric contents aspiration due to slow emptying, esophageal sphincter relaxation etc

Heroin: Opiates are problematic; Addisonian crisis, sudden hypotension, Methadone is a good substitute.

Cocaine: Potential airway damage from ‘snorting’, high sympathetic activity, co-dependence on other drugs (downers), acute intoxication?

Drug dependant pts may exhibit higher rates of HIV, hepatitis, STDs etc.

Addisons: Adrenal dysfunction with low glucocorticoid (and sometimes mineral corticoid) production often leading to severe hypotension. Causes: Auto-immune or long term steroid treatment withdrawal.

Question 40

Weight

Answer 40

Obesity will result in a restrictive pulmonary function pattern: ¯FRC, ¯TLC, ¯PaO2.

Pickwickian Syndrome: PCO2, Cor Pulmonale.

Diabetes Mellitus.

Chronic Hypertension.

Difficulty starting an IV, transferring or positioning the pt., intubation, ventilation, extubation

Clinician should consider rapid sequence induction—intubation.

Extubation should be allowed only with nearly full airway reflex (guarding).

Question 41

Head to Toe Assessment

Answer 41

CNS-Cerebral vascular accident, stroke

CVS-Hypertension, MI, ischemic heart disease, coagulopathy

RESP-OSA (major thing to know)

GI-GERD, problem with the liver

Renal-Any problems with the kidney that will affect excretion

MSK-Myosina Gravis (all of the nicotinic receptors will have destruction of those recpetors and a down regulation of them so there is less recptors. So for an action to occur you need more of the drug given.