Pre/Post Op Flashcards
when does DVT MC occur post-op
days 3-5
positive Homan sign
pain to the calf with dorsiflexion of foot
dorsiflexion
the action of raising the foot upwards towards the shin
if you think someone may have a DVT what screening modality FIRST
LE Doppler US
If there is low probability –> D Dimer first; if positive then US
most commonly used prophylactic measures for DVT before surgery
anticoagulation therapy such as low-dose unfractionated heparin 2 hours before surgery and every 8 to 12 hours after surgery until the patient is mobile along with intermittent pneumatic compression
pts should be mobile ASAP
What risk factors make up the Virchow triad?
Venous stasis, endothelial damage, and hypercoagulability
what veins are MC affected by DVT in LE
superficial femoral and popliteal veins in the thigh
the peroneal and posterior tibial veins
Examples of causes of vascular endothelial injury from virchows triad
surgery (total hip replacement), central venous catheterization, and trauma. In upper extremity DVT, endothelial injury due to central venous catheter, pacemaker, or injection drug use is the major causative factor
for what D Dimer level should an US be ordered
greater than 500 mg/L
definitive dx DVT
venography, but it is associated with increased risks and is rarely used in the clinical setting
study of choice for diagnosing PE
CT angiography
what do you use to diagnose PE if CT angiography is unavailable or contraindicated
ventilation-perfusion lung scan
What is phlegmasia alba dolens?
A rare complication of deep vein thrombosis (DVT) in pregnancy where the leg turns milky white
where does a pulmonary embolism arise from
often arises from thrombi in the systemic venous circulation or the right side of the heart but can also arise from invasive tumors in the venous circulation
what things cause a hyper coagulable state for virchows triad
autoimmune diseases, malignancy, use of oral contraceptives, pregnancy, genetic disorders such as factor V Leiden, and protein C or S deficiency
what things cause venous stasis for virchows triad
immobilization, chronic venous insufficiency, varicose vein, and paresis due to stroke
sx pulmonary embolism
sudden onset of dyspnea accompanied by pleuritic chest pain, apprehension, cough, hemoptysis, and diaphoresis
may have concomitant DVT
PE for pulmonary embolism
tachycardia
tachypnea
crackles
low grade fever
what D Dimer level can exclude a pulmonary embolism
< 500 ng/mL
what criteria score can rule out PE
well’s score
what will EKG show for PE
ECG shows sinus tachycardia and nonspecific ST-T findings. The classic S1Q3T3 (large S wave in lead I, Q wave in lead III, inverted T wave in lead III) that indicates cor pulmonale is seen in a minority of patients with pulmonary embolism
what will chest radiograph show for PE
nonspecific abnormalities such as Westermark sign (vascular cutoff sign) and Hampton hump (pleural-based wedge infarct), although they may also be normal
A normal chest X-ray in the presence of _______ is suspicious for pulmonary embolism
hypoxia
what will a ventilation-perfusion lung scan show for PE
perfusion defects with normal ventilation
what is the imaging test of choice for PE
CT pulmonary angiography
Pulmonary angiography is gold standard but not used commonly due to wide use of CT pulmonary angiography
what med is often given initially for PE tx
LMWH
when is Inferior vena cava filter used for tx of PE
used in hemodynamically stable patients who have failed or cannot tolerate anticoagulation
Patients who are at high risk for major bleeding events may be managed with
intermittent pneumatic compression or early ambulation, or, when chemical prophylaxis is used, very close monitoring for bleeding events
Wells Criteria for PE
signs and symptoms of deep vein thrombosis (3 points), PE is the most likely diagnosis (3 points), heart rate > 100 bpm (1.5 points), immobilization ≥ 3 days or surgery in the previous 4 weeks (1.5 points), previous objectively diagnosed DVT or PE (1.5 points), hemoptysis (1 point), and malignancy with active treatment in the past 6 months or under palliative care (1 point)
wells score of 0-4
PE unlikely
this score + negative D dimer = rule out PE
wells score > 4
PE likely
further workup warranted
when should fibrinolytic therapy be administered for PE
Fibrinolytic therapy should only be administered in unstable patients who demonstrate refractory hypotension and who do not have contraindications to thrombolysis
What is the McGinn-White sign?
S1Q3T3 pattern on ECG associated with pulmonary embolism
Vitamin K-dependent clotting factors include
factors II, VII, IX and X
how is warfarin efficacy measured
prothrombin time or international normalized ratio (INR)
pt on warfarin: If the INR is greater than the goal but less than 5
skip the next dose
pt on warfarin: If the INR is 5–10 and the patient is not at risk of bleeding
skip the next 1-2 doses
you can administer vitamin K if they are about to undergo surgery
pt on warfarin: If the INR is > 10 and there is no bleeding or a low-moderate risk of bleeding
hold warfarin
administer vitamin K
pt on warfarin: life-threatening bleed
hold warfarin
administer vitamin K
administer fresh frozen plasma
are pts w DM more likely to become hyper or hypoglycemic after surgery
hyperglycemic - maybe due to stress?
how long should metformin be withheld before surgery
24 h
how long should sulfonylureas be withheld before surgery
48-72 h
how long should ASA be stopped before surgery
one week
should beta blockers or levothyroxine be D/C before surgery
no
What is the best way to manage hyperglycemia during surgery?
A continuous intravenous insulin infusion
sx hypoglycemia
neurogenic symptoms (palpitations, tremor, hunger, sweating, and anxiety) and neuroglycopenic symptoms (irritability, weakness, drowsiness, headache, confusion, convulsions, coma, and even death)
dx hypoglycemia
serum blood glucose falls below 60 mg/dL
when does cognitive impairment develop for hypoglycemia
when blood glucose levels are < 50 mg/dL
Whipple triad
history of hypoglycemic symptoms, a fasting glucose level of 45 mg/dL, and immediate recovery on the administration of glucose
what is the Whipple triad suggestive of
insulinoma
if pt can’t eat or drink, how should you treat hypoglycemia
IV dextrose
glucagon can also be administered
what does protein status help predict
wound healing and the risk of surgical complications
Protein status is often measured by the following three laboratory measures:
serum albumin, serum transferrin, and serum prealbumin
what can be used to assess short-term changes in nutritional status
prealbumin
True or false: parenteral nutrition is preferred over enteral nutrition
False, enteral nutrition is preferred when possible
RF for stable angina
tobacco use, hypertension, hyperlipidemia, diabetes mellitus, and obesity
common sx of stable angina
deep, radiating chest pain that is triggered by a period of exertion and is relieved by rest
this is a common presenting symptom of coronary artery disease
diagnostic testing for stable angina
obtaining a baseline ECG and serum cardiac markers such as troponin
tx stable angina
Management of anginal symptoms includes the use of beta-blockers, calcium channel blockers, long-acting nitrates (such as isosorbide mononitrate), ivabradine, and ranolazine. Antiplatelet therapy, such as aspirin or clopidogrel, and a lipid-lowering agent, such as atorvastatin or rosuvastatin, should be initiated to prevent future cardiovascular events.
Patients with symptoms refractory to pharmacologic management should undergo coronary artery revascularization
when should unstable angina be suspected
Unstable angina should be suspected in a patient with chronic angina with increasing frequency, duration, or intensity of chest pain; a patient with new-onset angina that is severe and worsening; or a patient with angina at rest.
sx unstable angina
retrosternal chest pain or “pressure” that occurs at rest. Chest pain may radiate to the jaw, arms, back, shoulders, or epigastrium and may be associated with dyspnea, nausea, diaphoresis, or syncope
diagnosis of unstable angina
esting ECG, which may show a normal sinus rhythm but may also show ST segment depressions. Stress test with ECG often shows signs of ischemia, such as ST segment depression, although stress test should not be done during an acute episode. Laboratory studies reveal normal cardiac enzymes, including normal troponin and CK-MB
recheck cardiac markers after 6 hours
tx unstable angina
Nitroglycerin and morphine can be administered for pain control. Because unstable angina has a risk of progressing to myocardial infarction, aggressive medical management is indicated. Mortality-lowering therapy includes dual antiplatelet therapy with aspirin and a P2Y12 inhibitor, heparin, and a beta-blocker. Oxygen therapy should be given if the patient is hypoxic. Cardiac catheterization or revascularization should be performed within 1 to 2 days of admission, depending on the response to medical therapy and the results of a stress test. After acute management of unstable angina, the patient should continue daily aspirin, beta-blocker (metoprolol), nitrates, and a statin regimen
initial interventions for a STEMI
stabilizing the patient, continuous cardiac monitoring, measuring serial troponins, aspirin 325 mg, sublingual nitroglycerin tablets, a beta-blocker, and a statin
what is the most important aspect of STEMI treatment
restoration of myocardial blood flow
primary reperfusion therapies for STEMI
Primary percutaneous coronary intervention (PCI) and fibrinolytic therapy
which of the primary reperfusion therapies for STEMI is preferred
PCI is preferred if it can be performed within 120 minutes of first medical contact. Patients with symptom onset of < 2 hours in whom PCI cannot be performed in a timely manner should receive a fibrinolytic therapy (e.g., tenecteplase, reteplase, alteplase) with close monitoring and transfer to a facility where PCI can be performed
initial medical tx after dx of STEMI is confirmed
Aspirin and a P2Y12 receptor blockers such as ticagrelor or prasugrel
anticoagulation therapy such as unfractionated heparin, low-molecular-weight heparin, bivalirudin, or fondaparinux
The most common indications for urgent preoperative dialysis are
hyperkalemia and volume overload
what EKG changes are consistent with hyperkalemia
tall and peaked T waves
shortened QT interval
ST segment depression
when more severe:
prolonged PR interval
decreased or disappearing P waves
widening of the QRS complex
who should undergo dialysis before surgery
Patients who have hyperkalemia with a potassium of at least 6.3 mEq/L or who have any level of hyperkalemia with electrocardiogram changes must be dialyzed prior to surgery
in patients who do need dialysis, how before surgery should they undergo dialysis?
2 hours before – but ideally the day before
sx hyperkalemia
muscle weakness, flaccid paralysis, cardiac dysrhythmias, and ileus
in what pts is hyperkalemia MC
advanced kidney disease
Addison disease
Rhabdomyolysis
Burns
infection
vigorous exercise
metabolic acidosis
ACE’s
Potassium sparing diuretics (Spironolactone)
treatment for hyperkalemia when stable and no kidney impairment
calcium chloride
Intravenous insulin
dextrose
sodium bicarbonate
a beta-agonist such as albuterol
which of the therapies for hyperkalemia helps to stabilize the heart
calcium chloride
when is hemodialysis used to tx of hyperkalemia
renal impairment
unstable
other meds that can help excrete potassium
Loop diuretics and sodium polystyrene
Medical comorbidities that increase the risk of surgery
diabetes (especially insulin-dependent patients)
hypertension
chronic kidney disease cerebrovascular disease peripheral artery disease ischemic heart disease
Surgeries with high cardiac risk
laparoscopic total abdominal colectomy with ileostomy breast reconstruction with free flap
open cholecystectomy
open ventral hernia repair of incarcerated or strangulated hernia
Whipple procedure
what are the models that can provide a percentage risk of perioperative cardiovascular events
revised cardiac risk index (RCRI) and the American College of Surgeons surgical risk calculator (ACS-SRC)
what percentage would place a pt in the “high percentage” category for cardiac risks for surgery
risk of death at least 1%
Common postoperative pulmonary complications include
atelectasis, pneumonia, and venous thromboembolism
Atelectasis
the loss of lung volume caused by lung tissue collapse
Physical exam findings for atelectasis
bronchial breathing and hypoxemia
chest XR for atelectasis
tracheal shift toward the affected side
first line post-op interventions to prevent pulmonary complications
incentive spirometry
chest physical therapy
what days post-op does postoperative pneumonia tend to occur
days 5-10
what is the most common pulmonary complication among patients who die after surgery
postoperative pneumonia
sx post-op pneumonia
cough, fever, leukocytosis, and increased secretions
may need more oxygen
Physical exam findings pneumonia
tachypnea, increased work of breathing, and adventitious breath sounds, including rales or crackles and rhonchi. Increased tactile fremitus, egophony, and dullness to percussion also suggest pneumonia
Risk factors for developing postoperative pulmonary complications include
advanced age, prolonged surgery time, heart failure, smoking, asthma, and chronic obstructive lung disease
prevention of pulmonary complications in those with well-controlled asthma if endotracheal tube is needed
administration of an inhaled rapid-acting beta-agonist or nebulized treatment within 30 minutes prior to surgery if endotracheal intubation is needed
What should the peak expiratory flow rate be for patients with asthma before elective surgery
greater than 80% of their predicted value
An infection is considered community-acquired if one of the following is true:
the infection is diagnosed in an outpatient setting, there is no prior MRSA infection, there is no recent history of hospitalization, and there are no indwelling catheters or other percutaneous medical devices present
tx for hospital acquired MRSA
IV Vanc
tx for community acquired MRSA
clindamycin, trimethoprim-sulfamethoxazole, and tetracyclines
bc remember you can’t use beta lactams
when is central venous access indicated
patients with difficult IV access, hemodynamic monitoring, administration of vasopressors, extended administration of antimicrobial therapy, parenteral nutritional support, or chemotherapy
what are the three ways through which you can gain central venous access
internal jugular vein, subclavian vein, or femoral vein
for central venous access: which vein has the lowest risk of infection and thrombosis
subclavian vein
for central venous access: which vein has the highest risk of pneumothorax
subclavian vein
for central venous access: which vein is associated with the highest risk of thrombosis
femoral vein
for central venous access: which vein is associated with the highest risk of infection
femoral vein
Maintenance fluids
meeting the daily requirements for fluid and electrolyte intake, including correcting any deficits already present
preferred fluids in pre-op pts
lactated ringers
preferred fluids if ongoing fluid loss
Normal or half-normal saline
