Pestana Chap 3 - Pre-Op and Post-Op Care

Question 1

An ejection fraction under what percentage poses prohibitive cardiac risk for noncardiac operations? If an operation is done, is incidence of perioperative MI high and what is the mortality for such an event?

Answer 1

1) 35% (normal is 55%)

2) Incidence of perioperative MI is very high, and mortality for such an event is between 55 and 90%

Question 2

What is more commonly used as the preferred method of assessing cardiac risk instead of Goldman’s index of cardiac risk? What are the Goldman’s criteria in descending order of importance?

Answer 2

1) Functional status, based on the ability to cope with life’s demands, is more commonly used now
2) Jugular venous distension, recent myocardial infarction, premature ventricular contractions or any rhythm other than sinus, age over 70, emergency surgery, aortic valvular stenosis, poor medical condition, and surgery within the chest or abdomen

Question 3

What does jugular venous distention indicate? How significant is it for predicting high cardiac risk? What medications should be given to these patients pre-operatively?

Answer 3

1) The presence of congestive heart failure
2) It is the worst single finding predicting high cardiac risk
3) If at all possible, treatment with ACE inhibitors, beta-blockers, digitalis, and diuretics should precede surgery

Question 4

What is the worst finding predicting high cardiac risk after JVD? When should surgery be delayed until in the presence of this recent risk? If surgery is imperative sooner, where should the patient be admitted to and why?

Answer 4

1) Recent transmural or subendocardial MI
2) Operative mortality within 3 months of the infarct is 40%, but it drops to 6% after 6 months. Thus deferring surgery until then is the best course of action
3) Admission to ICU the day before surgery is recommended to “optimize cardiac variables”

Question 5

What is by far the most common cause of increased pulmonary risk? What is the problem with this risk? The presence of what should lead to evaluation in these patients? What should workup start with? If abnormal, what should workup continue with? What changes should precede surgery?

Answer 5

1) Smoking
2) The problem is compromised ventilation (high PCO2, low forced expiratory volume in 1 second [FEV1]), rather than compromised oxygenation
3) The smoking history or the presence of COPD
4) FEV1
5) Blood gases
6) Cessation of smoking for 8 weeks and intensive respiratory therapy (physical therapy, expectorants, incentive spirometry, humidified air)

Question 6

What two clinical findings and three lab values are used to predict operative mortality in patients with liver disease? How can the presence and severity of these factors be combined in a system based on class and percent mortality? Which patient would not be able to survive an operation in the context of the 5 above findings?

Answer 6

1) Encephalopathy, ascites, serum albumin, prothrombin time (INR), and bilirubin (only as it reflects hepatocyte function)
2) The current favorite system is Child class, in which class A has 10% mortality, class B 30%, and class C 80%
3) Specific numbers are misleading because so many other factors influence outcome. Suffice it to say that a patient in coma with huge ascites, albumin below 2, INR twice normal, and bilirubin above 4 could not survive a haircut, much less an operation

Question 7

What identifies severe nutritional depletion? How does the operative risk change under these circumstances?

Answer 7

1) Loss of 20% of body weight over a couple of months
2) Serum albumin below 3
3) Anergy to skin antigens
4) Serum transferrin level of less than 200 mg/dL (or a combination of the above)
5) Operative risk is multiplied manyfold

Question 8

As few as how many days of preoperative nutritional support (preferably via the gut) can make a big difference for surgical risk in severe nutritional depletion? How many days would be optimal if surgery can be deferred that long?

Answer 8

1) As few as 4 or 5 days

2) 7 to 10 days would be optimal if the surgery can be deferred that long

Question 9

Can a patient in diabetic coma undergo surgery? What must be achieved before this patient can undergo surgery? If the indication is a septic process, will complete correction of all variables be possible?

Answer 9

1) No. Diabetic coma is an absolute contraindication to surgery
2) Rehydration, return of urinary output, and at least partial correction of the acidosis and hyperglycemia have to be achieved before surgery
3) If the indication for surgery is a septic process, complete correction of all variables will be impossible as long as the septic process is present

Question 10

When does malignant hyperthermia develop? What does the temperature exceed? What two physiologic abnormalities also occur? May a family history exist? What is the treatment? What should you watch for the development for?

Answer 10

1) Shortly after the onset of the anesthetic (halothane or succinylcholine)
2) Temperature exceeds 104
3) Metabolic acidosis and hypercalcemia
4) Yes
5) IV dantrolene, 100% oxygen, correction of the acidosis, and cooling blankets
6) Watch for development of myoglobinuria

Question 11

How shortly after invasive procedures (instrumentation of the urinary tract is a classic example) is bacteremia seen? What two findings are present? How many blood cultures should be drawn? What is the treatment? What is a rare finding related to bacteria and the surgical wound within hours of surgery in the presence of severe wound pain and very high fever?

Answer 11

1) Within 30-45 minutes of invasive procedures
2) Chills and temperature spike to or exceeding 104F
3) 3
4) Empiric antibiotics
5) Gas gangrene

Question 12

What is postoperative (PO) fever in the usual range (101-103F) caused (sequentially in time) by?

Answer 12

Atelectasis, pneumonia, urinary tract infection, deep venous thrombophlebitis, wound infection, or deep abscesses

Question 13

What is the most common source of post-op fever on the first PO day? What must be done as part of workup for this fever? What is the ultimate therapy if needed?

Answer 13

1) Atelectasis
2) Rule out the other causes of post-op fever, listen to the lungs, do CXR, improve ventilation (deep breathing and coughing, postural drainage, incentive spirometry)
3) Bronchoscopy

Question 14

When will pneumonia occur after atelectasis if it is not resolved? Will the fever persist? What will CXR show? What else should be done as part of workup and treatment?

Answer 14

1) In about 3 days
2) Yes
3) Infiltrates
4) Sputum cultures and treat with appropriate antibiotics

Question 15

When does UTI typically produce fever? What does workup consist of? What is the treatment?

Answer 15

1) PO day 3
2) Urinalysis, urinary cultures
3) Treat with appropriate antibiotics

Question 16

When does deep thrombophlebitis typically produce fever? What is the best diagnostic modality? What should you anticoagulate with?

Answer 16

1) Starting on PO day 5 or thereabouts
2) Doppler studies of deep leg and pelvic veins (physical exam is worthless)
3) Heparin, transitioning later to warfarin

Question 17

When does wound infection typically begin to produce fever? What is found on physical exam? What is the treatment for cellulitis and for an abscess? What can be used to distinguish between the two when not easily distinguished clinically?

Answer 17

1) PO day 7
2) Erythema, warmth, and tenderness
3) Antibiotics if there is only cellulitis; open and drain the wound if an abscess is present
4) When these two cannot be easily distinguished clinically, sonogram is diagnostic

Question 18

When do deep abscesses (like subphrenic, pelvic, or subhepatic) start producing fever? What is the diagnostic test? What is therapeutic?

Answer 18

1) PO days 10-15
2) CT scan of the appropriate body cavity
3) Percutaneous radiologically guided drainage

Question 19

What is the most common trigger for perioperative myocardial infarction? How is it detected?

Answer 19

1) Hypotension

2) EKG monitor (ST depression, T-wave flattening)

Question 20

When does postoperative myocardial infarction occur? What fraction of cases present with chest pain? What is the most reliable diagnosis? How much greater is the mortality of a post-op MI than one without associated surgery? What is treatment directed at? What cannot be used and what may be used?

Answer 20

1) Within the first 2-3 PO days
2) Only 1/3 of cases present with chest pain
3) Troponin
4) Mortality (50 to 90%) greatly exceeds that of MI not associated with surgery
5) The complications
6) Clot busters cannot be used in the perioperative setting, but emergency angioplasty and coronary stent may be used

Question 21

When does pulmonary embolus (PE) typically happen? Describe the character of the pain, speed of onset, and associated symptom. How does the patient present on physical exam? What does ABG show?

Answer 21

1) PO day 7 in elderly and/or immobilized patients
2) Pleuritic pain of sudden onset, and is accompanied by shortness of breath
3) The patient is anxious, diaphoretic, and tachycardic, with prominent distended veins in the neck and forehead (a low CVP virtually excludes the diagnosis)
4) Hypoxemia and hypocapnia

Question 22

What is the gold standard test for PE and what test is done instead? What should you start treatment with after confirming the diagnosis? What should you add if PEs recur while anticoagulated or if anticoagulation is contraindicated?

Answer 22

1) Pulmonary angiogram, but it is rarely done. Spiral CT, often with the help of intravenous contrast (sometimes referred to as a “CT angio”), is the standard diagnostic test
2) Heparinization
3) IVC filter (Greenfield)

Question 23

Since prevention of thromboembolism will in turn prevent PE, what device can be used on anyone who does not have a lower extremity fracture? What is indicated for prevention in high risk patients? What are risk factors for PE?

Answer 23

1) Sequential compression devices
2) Anticoagulation
3) Age > 40, pelvic or leg fractures, venous injury, femoral venous catheter, and anticipated prolonged immobilization

Question 24

What pulmonary complication should you look out for as a distinct hazard in awake intubations in combative patients with a full stomach? What can it lead to? How can it be prevented? What does therapy start with if it occurs?

Answer 24

1) Aspiration
2) It can be lethal right away, or lead to chemical injury of the tracheobronchial tree and subsequent pulmonary failure, or secondary pneumonia
3) NPO and antacids before induction
4) Lavage and removal of acid and particulate matter (with the help of bronchoscopy), followed by bronchodilators and respiratory support

Question 25

When can intraoperative tension pneumothorax develop? How do they present? If the abdomen is open, how can quick decompression be achieved? If not, what can be inserted and where is it inserted?

Answer 25

1) In patients with traumatized lungs (recent blunt trauma with punctures by broken ribs) once they are subjected to positive-pressure breathing
2) They become progressively more difficult to “bag,” BP steadily declines and CVP steadily rises
3) Through the diaphragm
4) A needle can be inserted through the anterior chest wall into the pleural space. Formal chest tube has to be placed later