Casefiles 1: pre/periop management, shock Flashcards
Perioperative treatment with ? is a strategy that is no longer applied as a cardiac-risk-reduction strategy, because of the increase in risk of cerebral ischemic events
beta-blockade
statin therapy is more beneficial
Perioperative cardiac risk is low when patients have undergone successful ? within 5 years or ? between 6 months to 5 years prior.
surgical coronary revascularization
percutaneous coronary interventions (PCI)
? were the strongest predictors of perioperative mortality
ASA class, age, mFI (modified frailty scores), and wound class
AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA) STATUS CLASSIFICATION SYSTEM
ASA (1) healthy person;
ASA (2) mild systemic disease;
ASA (3) severe systemic disease;
ASA (4) severe systemic disease that is a constant threat to life;
ASA (5) moribund individual who is not expected to survive without the operation;
ASA (6) a declared brain-dead person undergoing organ procurement.
An “E” is added to the end of the ASA class if the operation is an emergency procedure that cannot be delayed.
Rivaroxaban’s half-life is related to the patient’s ?
creatinine clearance; therefore, it would be helpful to quantify the patient’s creatinine clearance prior to surgery
last dose should be btw 2-3 days prior to sx
general recommendation is to defer elective surgical procedures for at least ? after bare-metal stent placement and to defer surgery for ? after the placement of drug-eluting stents
6 weeks
6 to 12 months
to prevent stent thrombosis
if delaying sx is not an option: need to continue his dual anti-platelet therapy and proceed with his operation
CHAD2 scoring factors
CHF (1 point), Hypertension with systolic BP greater than 160 mm Hg (1 point)
Age more than 75 years (1 point),
Diabetes (1 point), and prior cerebrovascular accident (CVA) (2 points)
CHAD2 scoring
High-risk group: scores of 5 to 6; moderate-risk group: scores of 3 to 4; and low-risk group: scores of 0 to 2
stop warfarin ? before surgery and resuming warfarin dosing ? after the operation
5 days
12 to 14 hours
may need to bridge warfarin with heparin or LMWH in what surgical patients?
A patient with a mechanical valves, at high risk for venous thromboembolism, or atrial fibrillation with high stroke risk
Dabigatran (Pradaxa)
If necessary, ? can be performed to speed up the reversal of the drug effects.
oral direct thrombin inhibitor with a plasma half-life of 12 to 17 hours.
contraindicated in patients with severe renal dysfunction.
can monitor effects with aPTT and PT
hemodialysis can reverse drug effects
New oral anticoagulants (NOACs) are approved for what conditions
prevention of strokes and embolic complications associated with a fib, the treatment of DVTs and PEs, secondary prevention of DVT, and DVT prevention following knee or hip replacements.
Rivaroxaban (Xarelto)
oral direct factor Xa inhibitor with a plasma half-life of 5 to 9 hours in healthy individuals and 11 to 13 hours in elderly individuals.
contraindicated in patients with severe renal dysfunction.
metabolized and cleared by the liver, and levels may increase in liver failure patients
Rivaroxaban (Xarelto) interacts with ?
antifungal agents, protease inhibitors, and rifampin
anticoagulant effects of rivaroxaban can be determined based on ?
rivaroxaban can be reversed with ?
PT
activated prothrombin complex concentrate (aPCC) or prothrombin complex concentrate (PCC)
Apixaban (Eliquis)
oral direct factor Xa inhibitor with a plasma half-life of 8 to 15 hours.
effects measured by plasma anti-Xa levels (if available)
?? can be used to reduce bleeding in patients who develop excessive bleeding related to Apixaban (Eliquis)
four-factor PCC or aPCC
The common antiplatelet agents that irreversibly inhibit platelet functions include ?
ASA, clopidogrel, ticlopidine, and prasugrel
with each day the medication is stopped, there is a 10% to 14% restoration of platelet activity
reversible antiplatelet agents include ?
dipyridamole, cilostazol, and NSAIDs
For patients with high risk for cardiovascular or cerebral vascular events, what is the recommendation for anti platelet therapies?
recommended that antiplatelet therapies be continued during the perioperative period
For patients who are at moderate risk for cardiovascular events or are receiving antiplatelet agents for secondary prevention of cardiovascular diseases, what is the recommendation for antiplatelet therapy?
stop the antiplatelet therapy 7 to 10 days prior to surgery.
NAOCs are contraindicated in ?
pregnant and/or breast-feeding patients
Rivaroxaban and dabigatran are contraindicated in individuals with CrCl less than ?; apixaban is contraindicated in individuals with CrCl less than ?
30 mL/min
25 mL/min
Which of the following is a favorable characteristic associated with the new oral anticoagulant treatment?
fewer drug-drug interactions than warfarin; however, drug-drug interactions between the NOACs and some of the antifungal medications are important to note
The can however contribute to bleeding complications and no drug level monitoring is usually required.
NAOCs are not recommended for ?
the treatment of atrial fibrillation in patients with prosthetic valves
or in patients with low CHAD2 scores
ongoing assessment for shock
central venous catheter for continuous CVP monitoring and an arterial catheter for ongoing BP monitoring
Trans-thoracic echocardiography to assess intravascular volume and evaluate cardiac function
Serial measurements of serum lactate levels
central venous catheter
An intravenous catheter of sufficient length to measure the pressures in the superior vena cava when placed through the internal jugular vein or subclavian vein.
What is lactate?
when elevated what does it imply?
end-product of anaerobic metabolism
suggests a global deficit in oxygen delivery
can also become elevated as the result of inadequate clearance, such as with renal dysfunction
pulmonary artery catheter
A centrally placed catheter that can measure LV end-diastolic pressure and pulmonary artery pressures. can help gauge the patients’ LV functions
pulmonary artery catheters vs CVP catheters
PA catheters rarely used in the ICU settings now due to invasiveness, CVP provides comparable info
real advantage of PA is monitoring of patients with poor cardiac functions who are maintained on inotropic agents (such as acute heart failure patients).
Hypotension leading to shock can result from ?
decreased intravascular volume, cardiac pump failure, and/or acute vasodilation without sufficient increase in intravascular volume.
Think of the cardiovascular system as an arrangement of pump, pipes, and fluid volume
cardiac output (pump), vascular tone (pipes), and intravascular volume (fluid)
Hypovolemic surgical patients who respond initially to crystalloid resuscitation but then experience subsequent drops in blood pressure may have ?
ongoing bleeding that require operative intervention to control hemorrhage
resuscitations are generally more effective with the administration of blood products rather than crystalloids
Excess crystalloid administration to a bleeding patient can cause ?
dilution of clotting factors and thrombocytopenia, which can cause further bleeding and create a vicious cycle of worsening hypotension, coagulopathy, and hypothermia
etiologies of hypovolemic shock
Hemorrhage
Dehydration
etiologies of distributive shock
Sepsis
Neurogenic
Anaphylaxis
Medications
etiologies of intrinsic cardiac shock
Acute coronary syndrome
Cardiomyopathy
etiologies of extrinsic cardiac shock
Cardiac tamponade
Tension pneumothorax
Massive pulmonary embolus
normal hemodynamic variables
cardiac index: 2.4-3.0 L/min/m2
SVR: 800-1200 dyne-s or dyne-s/cm5
PCWP: 8-12 mm Hg
Prime Mover (initial causation): N/A
hemodynamic changes in Distributive (sepsis, neurogenic, anaphylaxis) shock
elevated cardiac index
Decreased SVR (because of decreased vascular tone)
Low to normal PCWP
causation: Decreased vascular tone
hemodynamic changes in Cardiogenic (MI, cardiomyopathy) shock
decreased cardiac index
Increased SVR
Increased PCWP
causation: Decreased cardiac contractility
hemodynamic changes in Hypovolemic (hemorrhage, dehydration) shock
Decreased cardiac index (because of decreased volume)
Increased SVR (to attempt to maintain BP)
decreased PCWP
causation: decreased preload
hemodynamic changes in Obstructive (tamponade, tension PTX, PE) shock
Decreased cardiac index
Increased SVR
Normal to increased PCWP
causation: Obstruction of blood flow
most patients with distributive shock exhibit what symptoms? due to ?
gradual dips in BP or minimal responses to fluid administration due to microvascular leak syndrome or excess vasodilation
appropriate treatments for distributive shock
vasoconstrictive medications such as norepinephrine for septic shock or phenylephrine (apha-1 agonist) for neurogenic shock rather than continued fluid administration
sepsis vs severe sepsis vs septic shock
Sepsis: hyper dynamic and febrile responses to infections.
Severe sepsis: occurrence of infection with septic host response and at least one end-organ dysfunction.
Septic shock: sepsis with persistent hypotension despite fluid administration
severe sepsis can carry a mortality of ? and septic shock can carry a mortality of ?
25% to 30%
50%
The two major treatment goals in septic shock are to ?, and to ?
identify and address the source of infection (source control)
restore tissue perfusion as soon as possible to minimize remote organ hypoperfusion that can lead to organ dysfunction
recommended end-points of resuscitation are target CVP of ?, a mean arterial pressure of greater than ?, and urine output greater than ?
8 to 12 mm Hg
65 mm Hg
0.5 mL/kg/h
If fluids alone are insufficient to achieve the blood pressure goals, a ? is recommended to help achieve the target blood pressures once intravascular volume depletion has been corrected
if fails what next?
norepinephrine (Levophed) drip
- continuous infusion of vasopressin at a constant rate of 0.03 U/min can be initiated to help improve catecholamine receptor responsiveness
- corticosteroids for septic shock who do not achieve sufficient responses to source control, fluid administration, and vasopressors
Source control in patients with a surgical infection frequently requires appropriate procedures to control the infection (eg, ?) in addition to antibiotics
drainage, debridement, bowel resection
What patients may not exhibit the expected tachycardia response to hemorrhage until late in the course of shock
Patients younger than 30 years of age with a good cardiac reserve and patients on beta-blockers
