Post operative CSRU questions Flashcards
What pulmonary function tests would prohibit cardiac surgery
No absolute number but operative mortality much higher in those with COPD.
P02 < 60 on room air pCO2 > 60 FEV1 < 65% VC FEV1 < 1 to 1.5 L DLCO < 50% predicted Vo2 max > 10 cc/kg, the best predictor but rarely measured failure to response to broncho dilators
What is mechanism of action of Heparin induced thrombocytopenia
IgG antibody binds to complex of platelet factor 4 and heparin leading to the formation of an immune complex.
The immune complex binds to platelets via platelet Fc receptors producing intravascular platelet activation, thrombocytopenia, and the potential complications
What are 3 types of HIT
Type 1: mild drop in plt count that stays > 100 000–management is to observe. repeat the count
Type II: moderate drop in < 100 000—without thrombosis. Treatment is to stop heparin, alternative anticoagulation and monitor for thrombus
Type III: HIT with evidence of thrombosis–mortality is about 30% and rate of amputation is 20%
What are alternatives to Heparin in a pt with HIT
- direct thrombin inhibitors
1) Argatroban (cleared by liver) short half-life
2) Liprudin (cleared by renal)
3) Danaparoid (cleared renal)
4) Ancrod
List predictors of increased low cardiac output syndrome
LVEF < 20% redo operation Emergency operation Female gender DM Left main recent MI < 30 days age > 70
What is definition of Low Cardiac output syndrome
SBP < 90 mmHg
CI < 2.2 L.min/m2
need for inotropes or IABP > 30 min in ICU
List 5 surgically correctable complications of acute MI
Ischemic ventricular septal defect (anterior or posterior)
Acute mitral regurgitation
ruptured papillary muscle
ruptured choradae
Left ventricular aneurysm
Ventricular freewall rupture
Cardiogenic shock from acute occlusion of one or more coronary arteries
What are complications of IABP
leg/limb ischemia thrombosis bleeding from puncture site Embolism Occlusion of branch vessel sepsis thrombocytopenia aortic rupture aortic dissection femoral neuropathy lymph fistula
What is mechanism of IABP
Augments diastolic coronary perfusion
reduces after load
Effects on LV decreases LV afterload during systole decreased myocardial oxygen consumption increased myocardial blood supply during diastole Effects on ascending aorta systole lower peak systolic pressure diastole peak aortic pressure is increased end diastolic pressure is lower
What are some facts about IABP
augments CO by 10 to 25%
Timing
should inflate immediately after closure of dicrotic notch (AV closure)
deflation as late as possible (timed to onset of R wave)
Triggers off arterial wave or ECG
Balloon should occlude aorta during diastole (34 or 40 cc Balloons)
How do you diagnose a perioperative MI
The following new finding on ECG Q wave (2 contiguous leads) LBBB Loss of R wave progression Presence of new ST-T changes and serum enzyme rise including one of Trop > 10 CK-MB >50 Ck-MB ratio of > 5 %
The presence of perioperative MI must include the presence of ECG changes
New definition in the 2011 guidelines
Increased biomarker 5x upper limit with new Q wave or LBBB
Or
Angiographic documentation
Or
Imaging documentation of loss of viability in new territory
3 causes of diaphragm paresis post-op
Phrenic nerve injury secondary to topical hypothermia Damage during LITA harvest (proximal end of ITA damage during pericardial incision damage during retraction of chest wall 0.5% if no topical cooling 32% with slush...(wow!!!) 2-6% with topical saline
Possible causes of recurrent laryngeal nerve injury
Dissection and direct injury during arch procedures
Cold solution in left pleural space
Injury during central line placement
May take 8 - 12 months to recover.
If severe respiratory compromise may need reintubation and traceostomy
Consult ENT
medialize the vocal chord by teflon injection
What are complications from Swan
Insertion bleeding hemothorax pnemo air embolism carotid puncture Related to presence in situ venous thrombosis ventricular arrhythmias RBBB Branch PA rupture
What is management of swan rupture
Blood from ETT, opacity of lung near PA catheter tip, bronchoscopy
ABC, secure airway, large IV, fluid, reverse coagulation aggressivlely
protect good lung patient with bleeding side down broch blocker or double lumen ETT or selective intubation angiography with embolization lobectomy/pneumonectomy risk of death is 30%
What are 6 most common general surgery issues post cardiac surgery
Upper GI bleeding pancreatitis hollow visucus perforation Mesenteric ischmia Hepatic failure cholecytisis
8 most common post-op pulmonary complications
Atelectasis Pleural effusion pneumonia pulmonary edema ARDS Pneumo Diaphragmatic paralysis Prolonged mechanical ventilation
What are two tests ordered for HIT
ELISA
Serotonin release assay
What is dosing of argatroban for HIT
2u/kg/min
What are Classification of neurological deficits post op
Type I: major focal neurological deficit, stupor and coma
Type II: deterioration in intellectual function or memory
List predictors of type I
Proximal aortic atherosclerosis (4.5) History of prior neurological disease (3.2) IABP DM HTN Increasing age unstable angina
Predictors of type II
ETOH HTN prior CABG PVD CHF Arrhythmias
Tests for HIT
Serotonin release test: measure release of radio-labeled serotonin from normal platelets washed with platelet serum. A test of platelet degradulation
ELISA: measures the levels of IgG-AB directed towards H-PF4 directly. More sensitive in those who otherwise do not have clinical evidence of disease
List indications for NO
Cardiac transplant pts Lung transplant pts pulmonary hypertension post valve surgery Right ventricular failure Lung transplantation Acute PE Pediatric cardiac surgery
