Preo-op testing

Question 1

joint commission requires all surgical pts to have what within 30 days of surgery?

Answer 1

• documented History and physical

Question 2

Why are preop evals so impt?

Answer 2

• 3-10% of pts undergoing surgical procedures experience serious morbidity, most of which results from cardiac, pulm, or infectious complications

Question 3

What are the goals of the preop eval?

Answer 3

• clearly defining the pt’s medical conditions
• eval the severity and stability of these conditions
• ID unrecognized comorbid disease and RFs for medical complications of surgery
• optimizing all medical conditions
• recommending periop measures to reduce the risk
• key is careful H and P (90% and 10%)

Question 4

Are routine preop tests recommended?

Answer 4

• no, overall risk of surgery is low in healthy individuals
• routine tests often lead to: false positive results, extra cost, possible delay of surgery, and medico-legal liability
• don’t perform tests unless there is a clear clinical indication
• what you order is dependent on hosp requirements and pt hx and risk of procedure
• when lab tests are felt to be necessary, it is reasonable to use results that were performed and were normal w/in the past 4 months, unless there has been a change in clinical status

Question 5

Tests recommended in certain pop groups?

Answer 5

• screening questionnaire and complete H and P
• H and H isn’t indicated unless major surgery, if older than 65, or in younger pts if significant blood loss is expected
• serum creatinine only needed if:
  over 50 w/ intermediate or high risk surgery, younger w/ anticipated hypotension or nephrotoxic drugs
• pregnancy testing in all women of reproductive age
• lytes, blood glucose, liver enzymes hemostasis, UA are not needed
• ECGs not needed for pts w/ low risk procedures
• CXR and PFTs not neeed unless over 50 w/ upper abdominal or thoracic surgery

Question 6

When is a preop CBC recommended?

Answer 6

• anemia is only seen in 1% of asx pts
• unanticipated WBC and platelet abnormalities are quite rare
• Hb and Hct where major blood loss is expected
• all pts older than 65 having major surgery

Question 7

What are the kidney fxn tests? When are these indicated preop? What is renal insufficiency a major predictor for?

Answer 7

• renal insufficiency is an independent RF for postop pulmonary complications and a major predictor of postop mortality
• serum creatinine most sensitive for kidney fxn (increased cardiac risk if creatinine greater than 2 mg/dL)
• rarely elevated in asx pts (0.2%), prevalence increases w/ age (9.8% ages 46-60)
• Order for pts older than 50 w/:
  moderate risk surgery
  anticipated hypotension
  possible use of nephrotoxic med

Question 8

What is hypernatremia assoc w/? When is lytes testing routeinely recommended?

Answer 8

• unexpected abnormalities occur in less than 1%
• hypernatremia is assoc w/ an increase in periop 30 day morbidity and mortality, although the relationship b/t most lyte derangements and operative morbidity isn’t clear
• since clinicians can predict most abnormalities based on hx - lytes are NOT routinely recommended unless: on diuretics, ACEI, ARB or has known renal disease

Question 9

Blood glucose and correleation w/ surgical complications? Testing of blood glucose?

Answer 9

• not routinely recommended for healthy pts
• 25% of pts over 60 have abnormal values
• asx hyperglycemia doesn’t increase complications
• the revised cardiac risk index ID diabetes as a RF for post op cardiac complications, however only pts w/ insulin tx diabetes were at risk
• surgical pts w/ diabetes do better if glucose well controlled

Question 10

When are LFTs recommendd?

Answer 10

• not routinely recommended
• unexpected liver enzyme abnormalities are quite rare, 0.3%
• pts w/ cirrhosis and acute liver failure have more M/M - pts will have signs and sxs picked up on H and P
• pts w/ mild abnormals and no known liver disease do fine
• in Hepatitis: ALT is always greater than AST
• in cirrhosis: AST is always greater thanALT

Question 11

When is routine platelet count, PT/INR required preop?

Answer 11

• not recommended if hx, PE, and family hx don’t suggest presence of a bleeding disorder
• incidence of bleeding disorders quite rare, even so, Hx more sensitive than PT or PTT in predicting complications
• required for pts on anticoagulants and neurosurgery
• PTT = intrinsic pathway
• PT = extrinsic pathway

Question 12

When is a UA recommended?

Answer 12

• not routinely
• looking for renal disease or infection: a serum creatinine levels are more sensitive for renal disease
• UTIs have the potential to cause bacteremia and post-surgical wound infections, particularly w/ prosthetic surgery
  so pts w/ positive UA and culture are tx w/ abx and proceed w/ surgery w/o delay but it is unclear whether a positive preop UA and culutre w/ subsequent abx tx prevent post-surgical infection

Question 13

When is preganncy testing recommended?

Answer 13

• for all women of reproductive age, hx not reliable

- knowledge that a woman is preg substantially changes periop management

Question 14

When is an EKG reqd preop?

Answer 14

• not routinely recommended, as it is rarely useful in absence of known cardiac disease
• abnormalities increase w/ age, rare under 45
• detecting recent MIs impt, increased M/M
• reqd for pts w/:
  CAD, CHF, arrhythmias, structural heart disease, PAD or CVD, diabetes
• can be considered for asx pts undergoing surgery w/ elevated risk (risk of major adverse cardiac event greater than 1%), maybe obesity

Question 15

Cardiac testing risk stratification?

Answer 15

• Cardiac risk in noncardiac surgery can approach 1% mortality: CV events leading cause of periop mortality
• multiple guidelines issued by ACC and AHA: address RFs and not recommended work-up
• eval fxnl status: Metabolic equivalents
• Revised cardiac risk index (Lee index) - 1 pt each:
  high risk surgery
  hx ischemic heart disease
  CVD
  insulin dep diabetes
  Creatinine greater than 2
• resting EKG: increased risk w/ presence of Q waves or significant ST segment elevation or depression
• if serious concerns - refer to cardiologist (may need stress testing, echo, revascularization)

Question 16

When are CXRs recommended?

Answer 16

• not unless suspected cardiopulm disease: abnormal findings frequent especially in elderly, (14,000 routine films and only 14 abnormal findings changes management)
• recommended for pts w/:
  known/suspected cardiopulm disease, or over 50 undergoing AAA repair or supper abdominal/thoracic surgery
• consider CXR for pts:
  AP and lat for morbidly obese (BMI over 40)
  and pts over 70 w/o RFs

Question 17

Why is pulm testing impt preop? When are PFTs reqd?

Answer 17

• pulm complications are impt source of morbidity/mortality -
  if older than 50, COPD, OSA, pulm HTN, or exercise intolerance, cough, unexplained dyspnea
• PFTs: spirometry, flow loops:
  a must for pts having lung resection, unexplained dyspnea or exercise intolerance, COPD or asthma

Question 18

What pts need a sleep study? Why is this impt?

Answer 18

• asx pts w/ OSA who follow tx and have not had wt changes since last sleep study are ok
• pts who have persistnet sxs, who don’t follow tx and have had changes in wt - need a sleep study
• pts w/ OSA have an increased risk of complications
• start tx prior to surgery

Question 19

What should you test in smokers?

Answer 19

• test for abstinence: serum continine levels:
  nicotine metabolite
  normal after 2 wks of abstinence
• smokers are less liekly to heal fusions and skin grafts

Question 20

Who is considered immunocompromised? Why do they need to be watched more closely during surgery and postop?

Answer 20

• HIV, chemo, RA/psoriasis on biologics, leukemias
• less likely to heal
• and are more likely to develop an infection