Chapter 3 - Pre-Op and Post-Op Care Flashcards
Ejection fraction under ___% (normal is 55%) poses prohibitive cardiac risk for non-cardiac operations. Incidence of perioperative MI is very high, with mortality for such an event between ___%.
35; 55-90
___, which dates from 1977, is no longer the preferred method of assessing cardiac risk. What is more commonly used now?
Goldman’s index of cardiac risk; functional status based on the ability to cope with life’s demands
While Goldman’s index of cardiac risk is no longer the preferred method of assessing cardiac risk, it remains useful for listing all the findings that predict trouble - list them in descending order of importance.
JVD Recent MI PVCs or any rhythm other than sinus >70 y/o Emergency surgery Aortic valvular stenosis Poor medical condition Surgery within the chest or abdomen
JVD, which indicates the presence of ___, is the worst single finding predicting high cardiac risk. If at all possible, treatment with what medications should precede surgery?
CHF; ACEIs, beta-blockers, digitalis, and diuretics
Recent transmural or subendocardial MI is the next worst predictor of cardiac complications. Operative mortality within 3 months of the infarct is ___%, but drops to ___% after 6 months. Thus, deferring surgery until then is the best course of action. If surgery is imperative sooner, what should be done?
40; 6; admission to the ICU the day before to “optimize cardiac variables”
What is the most common cause of increased pulmonary risk and why?
Smoking; compromised ventilation (high PCO2, low FEV1) NOT compromised oxygenation
What factors should lead to evaluation of pulmonary risk before surgery? What evaluation should be done?
Smoking history; presence of COPD
Start with FEV1 - if abnormal, follow with blood gases.
What should be done to mitigate pulmonary risk before surgery?
Cessation of smoking for 8 weeks and intensive respiratory therapy (PT, expectorants, IS, humidified air)
Two clinical findings and three lab values are used to predict operative mortality in patients with liver disease - what are they?
Encephalopathy and ascites; serum albumin, prothrombin time (INR), and bilirubin (only as it reflects hepatocyte function)
What is the current favorite system for predicting operative mortality in patients with liver disease and how is it stratified?
Child class
Class A - 10% mortality
Class B- 30% mortality
Class C - 80% mortality
Severe nutritional depletion is identified by what clinical factors?
Loss of 20% of body weight over a couple of months
Serum albumin <3
Anergy to skin antigens
Serum transferrin level<200 mg/dL
Discuss operative risk and pre-op support in the setting of severe nutritional depletion.
Operative risk is multiplied manyfold. As few as 4 or 5 days of pre-op nutritional support (preferably via the gut) can make a big difference. 7-10 days would be optimal if surgery can be deferred that long.
Diabetic coma is an absolute contraindication to surgery - what must be done before surgery?
Rehydration, return of urinary output, at least partial correction of the acidosis and hyperglycemia
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.
Timing of onset of malignant hyperthermia in the setting of surgery? Presentation?
Develops shortly after the onset of the anesthetic (halothane or succinylcholine)
Temp >104 F
Metabolic acidosis and hypercalcemia may occur
Possible family Hx
Rx malignant hyperthermia?
IV dantrolene 100% oxygen Correction of acidosis Cooling blankets Watch for myoglobinuria
Timing of onset of fever 2/2 bacteremia in the setting of surgery? Presentation?
Seen within 30-45 minutes of invasive procedures (instrumentation of the urinary tract is classic)
Chills and temp spikes to 104+ F
Manage bacteremia s/p surgery?
Blood cultures 3x, start empiric ABX
Although rare, severe wound pain and very high fever within hours of surgery should alert you to the possibility of ___ in the surgical wound.
Gas gangrene
Post-operative fever in the usual range (___ F) is caused sequentially in time by what 6 complications?
101-103; atelectasis -> pneumonia -> UTI -> deep vein thrombophlebitis -> wound infection -> deep abscesses
What is the most common source of post-op fever on the first PO day?
Atelectasis
Management of suspected atelectasis post-op?
Rule out the other causes of fever, listen to the lungs, do a CXR, improve ventilation (deep breathing and coughing, postural drainage, IS)
Ultimate therapy if needed is bronchoscopy
Pneumonia will happen in about ___ days if atelectasis does not resolve. Presentation and management?
3; fever will persist, CXR will show infiltrates. Sputum Cx, Rx with ABX
UTI typically produces fever starting on POD ___. Work-up and Rx?
3; UA and UCx. Rx with ABX
Deep thrombophlebitis typically produces fever starting on POD ___ or thereabouts. Work-up and Rx?
5; Doppler studies of deep leg and pelvic veins is the best diagnostic modality (exam is worthless); anticoagulate with heparin, transition to warfarin
Wound infection typically begins to produce fever on POD ___. Presentation and management?
7; erythema, warmth, and tenderness on exam. Rx with ABX ONLY if there is cellulitis. Otherwise, open and drain the wound if an abscess is present.
When these two cannot be easily distinguished clinically, sonogram is diagnostic.
Deep abscesses (in what 3 locations?) start producing fever around POD ___. Dx and Rx?
Subphrenic, pelvic, subhepatic; 10-15; CT scan of the appropriate body cavity is diagnostic. Percutaneous radiologically guided drainage is therapeutic
Perioperative MI may occur during the operation, triggered most commonly by ___, in which case it is detected by the EKG monitor (ST depression, T-wave flattening). When it happens post-op, it is typically within the first ___ post-op days. Presentation?
Hypotension; 2-3; chest pain in only 1/3 of cases. Otherwise, presents as complications
Dx post-op MI? Rx?
Most reliable diagnostic test is troponin; Rx complications. Clot busters cannot be used perioperatively, but emergency angioplasty and coronary stent may be used.
Pulmonary embolus typically happens around POD ___ in elderly and/or immobilized patients. Presentation?
7; sudden onset pleuritic chest pain with dyspnea. Anxious, diaphoretic, tachycardic, with prominent distended veins in the neck and forehead (CVP virtually excludes the diagnosis).
Dx post-op PE? Rx?
Standard test is a spiral CT with IV dye (CT angio); Rx with heparinization. Add an IVC filter (Greenfield) if PEs recur during anticoagulation or if anticoagulation is contraindicated.
Prevention of thromboembolism will prevent PE. How is this done?
Sequential compression devices can be used on anyone who does not have a lower extremity fracture.
High risk patients need anticoagulation. Risk factors include age >40, pelvic or leg fractures, venous injury, femoral venous cath, anticipated prolonged immobilization
Aspiration is a distinct hazard in awake intubations in combative patients with a full stomach. It can be lethal right away or lead to chemical injury of the tracheobronchial tree and subsequent pulmonary failure or secondary pneumonia. Prevention and Rx?
Prevent - NPO, antacids before induction
Rx - lavage and removal of acid and particulate matter with the help of bronchoscopy, followed by bronchodilators and respiratory support
___ can develop in patients with traumatic lungs (recent blunt trauma with punctures by broken ribs) once they are subjected to positive-pressure breathing. Presentation?
Intraoperartive tension PT; they become progressively difficult to “bag,” BP steadily declines, and CVP steadily rises
Rx intraoperative tension PT?
If the abdomen is open, quick decompression can be achieved through the diaphragm. If not, a needle can be inserted through the anterior chest wall into the pleural space (sneaking in under the drapes). Formal chest tube has to be placed later.
___ is the first thing that has to be suspected when a post-op patient gets confused and disoriented. It may be secondary to sepsis. Check ___ and provide ___ support.
Hypoxia; blood gases; respiratory
___ is seen in patients with a stormy, complicated post-op course, often complicated by sepsis as the precipitating event. Presentation?
ARDS; bilateral pulmonary infiltrates and hypoxia with no evidence of CHF
Centerpiece Rx of ARDS? Additional management?
Positive end-expiratory pressure (PEEP); must take care not to use excessive volume, which can lead to barotrauma
Source of sepsis must be sought and corrected
ECMO is becoming the new standard of care for ARDS refractory to PEEP -> main complication is intracranial bleeding, which can be minimized by using a venovenous connection to hook up the patient to the machine
___ is very common in the alcoholic whose drinking is suddenly interrupted by surgery. Presentation?
Delirium tremens; 2nd or 3rd POD, confusion, hallucinations, combative
Rx DT?
IV benzos (standard therapy); alcohol is also effective (IV 5% alcohol in 5% dextrose)…
Hyponatremia, if quickly induced by liberal administration of sodium-free IV fluids (like D5W) in a post-op patient with high levels of ADH (triggered by the response to trauma), will produce confusion, convulsions, and eventually coma and often death (“water intoxication”). Management?
Chart review confirms large fluid intake, quick weight gain, and rapidly lowering serum sodium concentration (in a matter of hours); best prevented by including sodium in the IV fluids. Once it happens, therapy is controversial and mortality is very high (young women are particularly vulnerable). Most authors use small amounts of hypertonic saline (aliquots of 100 mL of 5%, or 500 mL of 3%), perhaps add osmotic diuretics.
