UBP 2.8 (Long Form): Cardiovascular – CABG Flashcards
Secondary Subject -- Perioperative β-blockade/Cardiac Enzymes/ Myocardial Ischemia/PVCs on EKG/ Cardiac Pacing/Heparin Reversal/Post-bypass Coagulopathy/Intra-operative Awareness
Intra-operative Management
What monitors will you place for this surgery?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI:* The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
In addition to the ASA standard monitors,
I would place a 5-lead EKG to monitor for ischemia in lead V5 and arrhythmias in lead II.
I would also place an intra-arterial line for close monitoring of the patient’s blood pressure during induction and intubation.
If the surgeon requested it for postoperative management, I would also consider placing a pulmonary artery catheter prior to induction in order to note baseline cardiac function and to aid in monitoring the patient’s cardiac function during this time where there is increased risk of hemodynamic instability.
After induction, I would place a TEE to provide an additional monitor of cardiac function.
Finally, I would place a BIS monitor to help assure adequate anesthesia during cardiopulmonary bypass, and a Foley catheter to monitor urine output.
Intra-operative Management
Wouldn’t the use of TEE eliminate the need for a PA catheter?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
Not necessarily.
While TEE provides more accurate determinations of filling volumes and contractility, and while it is a more sensitive indicator of myocardial ischemia, it would not be available during induction and intubation, and is not usually continued postoperatively in the ICU where hemodynamic instability may persist.
Therefore, a pulmonary artery catheter may be indicated, even when planning to use TEE, if close hemodynamic monitoring is desired during induction and/or during post-operative management.
Intra-operative Management
The surgeon states that he would like a PA catheter, and you agree to place one.
Given that the patient has a right carotid bruit, where would you place your central line?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
Given the right carotid bruit (risk of thrombus dislodgement with accidental carotid puncture),
the left lower lobe atelectasis (the subclavian approach is associated with an increased risk of pneumothorax),
and the need for anticoagulation (the subclavian vein is not compressible),
I would probably place the central line in the left internal jugular vein.
While there is a theoretical risk of hematoma formation and subsequent compression of the non-diseased carotid artery resulting in decreased cerebral perfusion, this risk is probably minimal in this patient with asymptomatic carotid artery disease, who likely has adequate collateral circulation.
To further minimize this risk, I would use ultrasound guidance during placement.
However, if the patient’s carotid disease were severe and/or symptomatic, I would consider using the brachial or subclavian artery approach.
Intra-operative Management
Do you need to discontinue Heparin prior to A-line and CVP placement?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
While the heparin infusion does increase the risk of bleeding and hematoma formation during line placement, I would NOT discontinue the infusion due to risk of further compromising coronary perfusion.
To minimize needle sticks and the risk of hematoma, I would use ultrasound guidance during line placement.
Intra-operative Management
How will you induce this patient?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
Assuming his airway were reassuring, I would:
- place the appropriate monitors;
- position the patient in reverse-trendelenburg to improve respiratory mechanics, facilitate rapid intubation, and reduce the risk of passive regurgitation in this obese patient with diabetes (obesity and diabetes place him at risk for rapid desaturation, difficult intubation, and aspiration);
- note his baseline cardiac function;
- preoxygenate with 100% oxygen and a tight mask seal;
- provide aspiration prophylaxis and apply cricoid pressure (due to possible delayed gastric emptying);
- induce him with etomidate and a high dose of narcotics to avoid cardiovascular depression; and
- intubate the patient.
My goals would to be provide a sufficient level of anesthesia to blunt the sympathetic response to intubation, while maintaining hemodynamic stability and safely securing the airway.
Intra-operative Management
Prior to the chest incision the BP drops to 80/50 mmHg, pulse is 50.
What is the likely etiology?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
This moderate hypotension is most likely due to cardiovascular depression following the administration of induction drugs and subsequent volatile agent.
If his diabetes has led to the development of autonomic neuropathy, then this would potentially contribute to his hemodynamic instability.
This drop in blood pressure is not surprising, since the period after induction and prior to surgical stimulation is often associated with hypotension, frequently requiring reduced anesthetic depth and/or pharmacologic support.
However, other causative or contributory factors, such as –
- arrhythmia,
- cardiac ischemia, and
- tension pneumothorax, should be ruled out (increased risk of pneumothorax due to recent central line placement and possible pulmonary disease).
Intra-operative Management
Prior to chest incision the BP drops to 80/50 mmHg, pulse is 50.
What would you do?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
I would deliver 100% oxygen, ensure adequate ventilation and oxygenation, auscultate the chest, verify the blood pressure, check the EKG, and obtain filling pressure and cardiac output from the PA catheter.
Assuming that my initial suspicion was correct, that the hypotension was not worsening, and that there were no signs of ischemia, I would decrease the volatile anesthetic concentration, give a fluid bolus, place the patient in trendelenburg position, and, if necessary, treat with a small dose of a direct acting vasopressor (an indirect vasoconstrictor, such as ephedrine, would be less effective in the setting of autonomic neuropathy).
As long as the patient’s condition was stable, I would treat moderate hypotension conservatively during this period of low stimulation, rather than risk hypertension and tachycardia with overly aggressive treatment just prior to incision and sternotomy.
Intra-operative Management
His blood pressure returns to baseline, but with the initiation of CPB, it suddenly drops again, this time to 74/42 mmHg.
What do you think may have caused this hypotension?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
This hypotension is most likely due to the hemodilution and sudden decrease in systemic vascular resistance that often occurs with injection of the dilute priming solution.
Consideration should also be given to –
- monitor malfunction;
- anesthetic-induced decreases in vascular tone;
- pump malfunction;
- inadequate venous return to the pump
- (table too low,
- hypovolemia,
- caval obstruction,
- malposition of the venous cannula);
- aortic dissection; and
- kinking, clamping, or malpositioning of the arterial cannula.
Intra-operative Management
What if the patient exhibited unilateral face blanching, right-sided mydriasis, and chemosis?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
This constellation of symptoms is consistent with malpositioning of the arterial cannula with flows of the priming solution directed toward the innominate artery.
Increased systemic line pressures in the CPB circuit and a comparison of left and right upper extremity pressures showing relatively higher pressures in the right radial artery are other signs consistent with this complication.
Intra-operative Management
Pt exhibits unilateral face blanching, right-sided mydriasis, and chemosis – Would you cancel the case?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
Given the potential for cerebral injury following this event,
I would prefer to delay the case, if possible, to allow time for resolution of any cerebral edema and/or elevations in ICP.
However, this patient’s symptoms suggest significant coronary disease with myocardium at risk.
If it was determined that surgical delay was unacceptable, I would proceed with the case, taking steps to reduce cerebral edema (e.g., mannitol, head-up positioning) and to preserve adequate cerebral perfusion.
Intra-operative Management
The decision is made to proceed with the case.
During CPB the glucose gradually climbs to 250 mg/dL. Would you treat this?
What if it were 300 mg/dL?
What are the potential complications of hyperglycemia?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
Yes.
Hyperglycemia is common during CPB in part due to the decreased glucose metabolism and marked increase in stress hormones, catecholamines, and cortisol, associated with hypothermia.
Studies have identified hyperglycemia as an independent risk factor for increased short-term and long-term morbidity and mortality following cardiovascular surgery.
This is most likely because cerebral ischemia is more likely to occur during this type of surgery, and hyperglycemia exacerbates neuronal injury under these conditions.
Therefore, I would start an insulin infusion and closely monitor blood sugar through the perioperative period with the goal of maintaining blood glucose levels below 150 mg/dL, while, at the same time, avoiding hypoglycemia.
Intra-operative Management
How do you prepare to wean patients off of CPB?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
In preparing the patient to come off of CPB, I would –
- ensure normothermia;
- correct any anemia, electrolyte abnormalities, or metabolic disturbances;
- turn on and check anesthetic alarms and monitors;
- recalibrate and zero transducers;
- check lung compliance and initiate ventilation;
- ensure that the heart is de-aired;
- ensure adequate cardiac function using TEE and other hemodynamic data;
- administer benzodiazepines to prevent awareness during rewarming; and
- ensure the availability of a pacing device and resuscitation drugs.
During weaning, I would closely monitor cardiac function and administer inotropes and vasoactive drugs as necessary.
Post-operative Management
Upon arrival in the ICU, the patient’s blood pressure drops to 82/65 mmHg. You look at the EKG and note a heart rate of 40 and multiple PVCs. What would you do?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
I would –
- confirm adequate ventilation and oxygenation,
- check the EKG,
- verify proper pacemaker function,
- ensure appropriate infusion concentrations,
- note chest tube drainage,
- collect all hemodynamic data from the PA catheter,
- evaluate the patient’s volume status,
- check electrolytes, and
- treat accordingly.
Post-operative Management
Pacing wires are in place, but the pacing cables are not capturing. You check the pacemaker and note that the pacing wires appear to be in place, but there is failure to capture. Why might this happen?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
There are a variety of conditions that might result in failure to capture, including:
- myocardial infarction (may significantly increase the energy requirement for depolarization);
- lead dislodgement;
- the delivery of insufficient energy to achieve depolarization;
- pacemaker malfunction;
- acid-base disturbances, which can be caused by, or exacerbated by, hypoventilation or hyperventilation;
- electrolyte abnormalities (K+, Ca+, and magnesium abnormalities can all potentially raise the depolarization threshold); and
- abnormal antiarrhythmic drug levels.
Post-operative Management
The patient’s BP is now 70/52 mmHg. What would you do?
- (A 64-year-old, 100 kg, man is brought to the operating room for CABG.*
- HPI: The patient was asymptomatic until 4 days ago when he developed severe chest pain with exertion that responded to NTG and metoprolol. EKG shows anterolateral ST-segment depression. Laboratory testing was negative for the CK-MB isoenzyme, but showed elevated Troponin enzymes. Subsequent cardiac catheterization revealed 90% left main coronary artery stenosis. His ejection fraction is 45% and his left ventricular end-diastolic pressure (LVEDP) rose from 18 mmHg to 28 mmHg during ventriculography.*
- PMHx: Poorly controlled type II diabetes mellitus, Congestive Heart Failure, Hypertension x 15 years, Tobacco use of 1 ppd x 34 years*
- Meds: Nitroglycerin and heparin infusions, metoprolol, digoxin, NPH insulin, Albuterol, Atrovent*
- Allergies: NKDA*
- PE: Vital Signs: P = 90, BP = 128/72 mmHg, R = 16, T = 37.2ºC*
- Airway: Mallampati II, full cervical ROM, teeth intact*
- Head/Neck: Right carotid bruit*
- Pulmonary: Wheezing*
- Cardiovascular: regular rate; no murmur*
- CXR: Left ventricular prominence*
- EKG: Sinus Rhythm, V4-V6 ST-segment depression, no Q-waves*
- Lab: Hgb = 12 gm/dL, Glucose = 197 mg/dL, Na = 140 mEq/L, K = 4.2 mEq/L, Digoxin Level = 2.2 ng/mL)*
I would –
- ensure adequate ventilation and oxygenation;
- attempt transcutaneous, transvenous, or transesophageal pacing;
- correct any electrolyte or metabolic abnormalities; and,
- if necessary, administer atropine or epinephrine and start chest compressions.
