Indian Journal of Anaesthesia  
About us | Editorial board | Search | Ahead of print | Current Issue | Past Issues | Instructions
Home | Login  | Users Online: 233  Print this pageEmail this pageSmall font sizeDefault font sizeIncrease font size    




 
ARTICLES
Year : 2007  |  Volume : 51  |  Issue : 4  |  Page : 280 Table of Contents     

Anaesthetic considerations in cardiac patients undergoing non cardiac surgery


1 Professor & Head, Department of Anaesthesiology and Resuscitation, Dayanand Medical College & Hospital, Ludhiana, India
2 Assistant Professor, Department of Anaesthesiology and Resuscitation, Dayanand Medical College & Hospital, Ludhiana, India

Date of Web Publication20-Mar-2010

Correspondence Address:
Geeta Tayal
1841, Street No. 6, Maharaj Nagar, Ludhiana. 141001
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


Rights and PermissionsRights and Permissions

Keywords: Peri-operative anaesthesia care, Cardiac diseases, Non cardiac surgery


How to cite this article:
Kaul TK, Tayal G. Anaesthetic considerations in cardiac patients undergoing non cardiac surgery. Indian J Anaesth 2007;51:280

How to cite this URL:
Kaul TK, Tayal G. Anaesthetic considerations in cardiac patients undergoing non cardiac surgery. Indian J Anaesth [serial online] 2007 [cited 2017 Jul 26];51:280. Available from: http://www.ijaweb.org/text.asp?2007/51/4/280/61157


   Introduction Top


Administering anaesthesia to patients with preexist­ing cardiac disease is an interesting challenge. Most com­mon cause of peri-operative morbidity and mortality in cardiac patients is ischaemic heart disease (IHD). IHD is number one cause of morbidity and mortality all over the world [1] . Among the estimated 25 million patients in the United States who undergo surgery each year, approxi­mately 7 million are considered to be at high risk of IHD. Indian figures are not available. Goldman et al reported that 500,000 to 900,000 MIs occur annually worldwide with subsequent mortality of 10-25%.Care of these pa­tients require identification of risk factors, pre-operative evaluation & optimization, medical therapy, monitoring and the choice of appropriate anaesthetic technique and drugs.

Risk factors Influencing peri-operative cardiac morbidity are:

i. Recent myocardial infarction ii. Congestive cardiac fail­ure iii. Peripheral vascular disease iv. Angina pectoris v. Diabetes mellitus vi.Hypertension vii. Hypercholester­olemia viii. Dysrrhythmias ix. Age x. Renal dysfunction xi. Obesity xii. Life style and smoking


   Risk stratification Top


In 1977, Goldman and colleagues proposed the land­mark Cardiac Risk Index [2] . Although not validated pro­spectively, this index was used extensively for preopera­tive cardiac risk assessment for the next two decades. Subsequently, other cardiac risk indices were proposed and adopted. In 1996, a 12-member task force of the American College of Cardiology and the American Heart Association (ACC/AHA) published guidelines regarding the perioperative cardiovascular evaluation of patients undergoing noncardiac surgery [3] . In March 2002, these guidelines were updated based on new data. The overrid­ing theme remains that "preoperative intervention is rarely necessary, simply to lower the risk of surgery, unless such intervention is indicated irrespective of the perioperative context". No test should be performed unless it is likely to influence patient treatment.


   Evaluation Top


Patients having any sort of cardiac ailment need to be evaluated properly preoperatively [6] .


   History Top


History elicits the severity, progression and func­tional limitation introduced by cardiac disease. History should include:-.

  1. Exercise tolerance :- It depicts the cardiac reserve. It can be Excellent -history of participation in sports like swimming, football, tennis, basket-ball, skating etc. Adequate-patient able to climb stairs, run a short dis­tance. Poor- able to do leisure activities only e.g. slow ballroom dancing or can walk around in the house only.
  2. Angina pectoris:-It is the symptomatic manifestation of myocardial ischaemia characterized by typical substernal pain which is evoked by physical exertion and relieved by rest or sublingual nitroglycerine.
  3. Myocardial infarction:- The incidence of myocardial infarction during the peri-operative period is related to time period since the previous myocardial infarc­tion. According to Tarhan et al - incidence of peri­operative re-infarction is 37% if the time elapsed is less than 3 months,16% when time elapsed is 4-6 months and 5% when time elapsed is more than 6 months. This is the basis for recommendation to wait for 6 months after MI for elective major surgery.
  4. Co-existing noncardiac diseases


  5. i. Peripheral vascular disease ii. Cerebro vascular disease iii. Chronic obstructive pulmonary disease in patients with history of cigarette smoking iv. Renal dysfunction may be associated with chronic hyper­tension v. Diabetes- May be the cause of silent MI[Additional file 1] vi. Anaemia, polycythemia, thrombocytosis when present will need careful management.

  6. Current medications-Awareness about the medica­tions that patient is taking is important during anaes­thesia. All cardiac medications like beta blockers, calcium channel blockers, nitrates should be contin­ued until the morning of surgery. Patient may be on oral anticoagulants or aspirin which should be stopped 5-7 days prior to surgery.
  7. Congestive cardiac failure:-The stress of anaesthesia, surgery and fluid replacement may re­sult in overt failure in patients bordering on conges­tive heart failure.
  8. Dysrrhythmias.

   Examination Top


A careful general physical examination should be done. It should include assessment of vital signs like blood pressure, pulse rate and rhythm, jugular venous pulse, oedema, pallor, cyanosis, clubbing , jaundice, lym­phadenopathy. In systemic examination, cardiovascular system should be examined for heart sounds & any mur­mur. Further evaluation is needed as per the findings. Respiratory system also needs to be assessed in details.


   Laboratory investigations Top


Cardiac specific tests like ECG, echocardiography to know ejection fraction, any valvular lesion , wall mo­tion abnormalities, LV function and pressure gradients, Holter monitoring, Treadmill test, thallium scintig­raphy to detect myocardium at risk, radionuclide ven­triculography, dobutamine stress test(DST) for evalu­ating inducible ischemia in patients who have poor func­tional capacity, coronary angiography in patients where DST is positive should be done.


   Anaesthetic management Top


Anaesthesia goals remain

i. Stable haemodynamics ii. Prevent MI by optimiz­ing myocardial oxygen supply and reducing oxygen de­mand iii. Monitor for ischaemia iv. Treat ischemia or inf­arction if it develops v. Normothermia vi. Avoidance of significant anaemia

Management depends upon the type of surgery whether emergency or elective. For emergency surgery proceed for the surgery with medical management of cardiac ailment. For elective surgery perioperative management depends upon various clinical risk factors and surgery specific risk factors [3] .


   Clinical risk factors Top


Obtained by history, physical examination & review of ECG, the clinical risk factors are grouped into 3 categories­

  1. Major clinical predictors are unstable coronary syn­drome, decompensated heart failure, significant dysrrhythmia and severe valvular disease. They man­date intensive management even if that leads to de­lay or cancellation except emergency surgery.
  2. Intermediate clinical predictors are mild angina pecto­ris, previous MI by history or pathological Q waves, compensated or prior heart failure, insulin dependent diabetes mellitus, and renal insufficiency. These are markers of enhanced risk of peri-operative cardiac complications. It appears reasonable to wait for 4-6 weeks after MI for elective surgery.
  3. Minor clinical predictors are hypertension, LBBB, nonspecific ST-T wave changes and history of stroke. They have not proved to increase risk independently.

   Surgery specific risk factors Top


  1. High risk surgeries- (emergent major operations particularly in the elderly, aortic and other major vascular surgery, anticipated prolonged surgical proce­dures associated with large fluid shifts or anticipated blood loss) are often reported to have a cardiac risk of greater than 5%.
  2. Intermediate risk surgeries- (carotid endarter­ectomy, head and neck surgery, intraperitoneal and intrathoracic surgery, prostate surgery) are reported generally to have cardiac risk of less than 5%.
  3. Low risk procedures:- (endoscopic procedures, su­perficial procedures, cataract surgeries, breast surgery) are reported to have less than 1% risk of cardiac events.

   Preoperative management Top


At risk patients need to be managed with pharmaco­logic and other perioperative interventions that can ame­liorate perioperative cardiac events. Three therapeutic options are available before elective noncardiac surgery.­

  1. Optimisation of medical management
  2. Revascularization by PCI, revascularization by sur­gery ( CABG)
However it may not be necessary to intervene pre­operatively (except for beta blocker therapy or c 2 ago­nists) to improve perioperative outcome. Beta blockers have been shown to be useful in reducing perioperative morbidity and mortality in high risk cardiac patients and preferably titrated to a heart rate of 50 to 60 bpm [7] . α2 agonists by virtue of their sympatholytic effects can be useful in patients where beta blockers are contraindicated. Nitroglycerine lowers LVEDP by reducing preload . It improves collateral coronary flow and reduce systemic B.P. Other agents like calcium channel blockers, ACE inhibitors, aspirin, insulin, statins prove to be beneficial perioperatively.

Coronary intervention should be guided by patient's cardiac condition (unstable angina, left main or equivalent CAD, three vessel disease, decreased LV function) and by the potential consequences of delaying the noncardiac surgery for recovery after coronary revascularization [3] .Patients who underwent PCI had better outcome after noncardiac surgery. However the need for dual anti-plate­let therapy for several months to one year can signifi­cantly impact the perioperative course. Acute postopera­tive stent thrombosis has been reported when anti-plate­let agents were temporarily held preoperatively to reduce chance of bleeding. Continuing the therapy can lead to significant postoperative bleeding. Discontinuing or modi­fying anti-platelet therapy should involve a multidisciplinary team of cardiologist, surgeon, anaesthesiologist [8] .


   Preanaesthetic considerations Top


Preoperative visit to the patient is very important. A good rapport should be made with the patient and written consent obtained. Patient should be explained about the risk of surgery and anaesthesia. It is important to continue the medications till the day of surgery like beta blockers, calcium channel blocker, digitalis. Potassium level should be normal as hypokalemia can cause digitalis tox­icity. Anticoagulants should be stopped.


   Premedication Top


Significance of premedication in allaying anxiety in cardiac patients is of paramount importance. This is to prevent increase in B.P. and HR which can disturb the myocardial oxygen supply and demand and can induce ischaemia. Any combination of benzodiazepine like lorazepam and opioid like morphine should be given one hour prior to arrival in operation theatre.

The following algorithm helps in easy reference for planning perioperative management of cardiac patients undergoing noncardiac surgery.

[Additional file 2]


   Intraoperative management Top


Monitoring

Incidence of ischaemia in the intraoperative period is low (as compared with pre and postoperative period)

i. ECG is the most commonly used monitoring tool . If ECG is to be used effectively as an ischaemic monitor, the monitor should be set on diagnostic mode. Monitoring three ECG leads (II,V4,V5 or V3,V4,V5) improves rec­ognition of ischaemia. The ST segment trending system also helps in the detection of ischaemia ii. Blood pressure iii. Pulse oximetry iv. Capnography v. Temperature moni­toring vi. Urine output monitoring vii. Central venous pres­sure viii. Pulmonary artery pressure and cardiac output- can be measured with pulmonary artery catheter as re­quired. In a haemodynamically unstable patient, the re­quirement of volume or inotropes can be judiciously cal­culated and response monitored closely ix. TEE (transesophageal echocardiography) is a sensitive moni­tor for ischaemia. However TEE is not advocated for routine use [9] .

Choice of anaesthetics

The anaesthesiologist should select the drugs with the objective of minimizing demand and optimum supply of oxygen. Along with the anaesthetic agent some cardiac drugs should be readily available to maintain haemodynamics, to prevent & treat ischaemia, if it occurs.

General anesthesia

1. Intravenous anaesthetics

Thiopentone
-It reduces myocardial contractil­ity, preload and blood pressure and there is slight in­crease in heart rate. It should be administered slowly and with caution.

Propofol - It reduces arterial blood pressure and heart rate significantly. There is dose dependent reduc­tion in myocardial contractility. It can be used in with good ventricular function but is not good induction agent for patients with CAD.

Ketamine - It is not good in IHD and valvular heart disease patients. It is however a useful agent in situations like cardiac tamponade and cyanotic heart disease.

Midazolam - It produces decrease in mean arte­rial pressure and increase in heart rate. It provides excel­lent amnesia and is widely used for patient with CAD

Etomidate - It causes minimum haemodynamic changes. It is excellent for induction in patients with poor cardiac reserve.

2. Narcotics - Morphine is the preferred drug for its relative cardiac stability and very good analgesic effect. It produces arterial and venous dilatation ,resulting in reduction of after load and preload. Newer narcotic an­algesic agents like fentanyl, alfentanyl and sufentanil also provide adequate cardiac stability and pain relief.

3. Inhalational agents - Isoflurane is recommended in patients with good myocardial contractility. Halothane has the disadvantage of myocardial depression and po­tential of dysrrhythmias.

4. Nitrous oxide -It provides stable haemodynamics in cardiac patients.

5. Muscle relaxants -Vecuronium produces mini­mum haemodynamic alterations and is short acting, there­fore suitable for use in cardiac patients. Pipecuronium, mivacurium, doxacurium are newer non depolarizing muscle relaxants without any significant cardiovascular side effects.

6. Glycopyrrolate -It is preferred over atropine since it produces less tachycardia & should be used only if specifically required.

Regional anesthesia

The potential and well known advantage of regional anesthesia over G.A should be an asset in cardiac pa­tients if the surgery can be performed under regional block. Patient should be nicely premedicated without any appre­hension. Disadvantages of regional anesthesia include hypotension from uncontrolled sympathetic blockade and need for volume loading can result in ischemia. Care should be taken while giving local anaesthetic because larger doses can cause myocardial toxicity and myocar­dial depression. Use of epinephrine with local anaesthetic is not recommended [10].


   Managing intraoperative complications Top


1) Intraoperative ischaemia

1 If patient is haemodynamically stable-

1- Beta blockers ( I/V metoprolol upto 15mg)

I/V Nitroglycerine

Heparin after consultation with surgeon

2 If patient is haemodynamically unstable

­Support with inotropes

Use of intraoperative ballon pump may be nec­essary

Urgent consultation with cardiologist to plan for earliest possible cardiac catheterization

2) Other complications like dysrrhythmias, pacemaker dysfunction should be managed accordingly


   Post operative management Top


Goals are same as intraoperative

i. Prevent ischaemia ii. Monitor for MI iii. Treat­ment for MI

Although most cardiac events occur within first 48 hours, delayed cardiac events (within first 30 days ) still happen and could be the result of secondary stress. Post operative stress of extubation, pain, sepsis, haemorrhage, anaemia, respiratory problems can increase the demand on the heart and should be minimized and treated.


   Valvular heart diseases Top


Patients with valvular heart diseases coming for surgery present many challenges to the anaesthesiologist. Now it is no longer necessary or even advisable to delay surgery until advanced symptoms are present. Valvular surgery is advised in such patients before elective non­cardiac surgery. The perioperative physician has to be aware of the varying effects of haemodynamic variables on this sub population of patients. The five variables in dealing with the valvular heart diseases are important. They are:- i. Preload ii. After load iii. Myocardial contrac­tility iv. Heart rate v. Rhythm.

Keeping in mind these variables , the anaesthetic technique can be chosen with a view to maintain optimal cardiac performance. In general ,the goal in stenotic le­sions is to enhance forward flow , where as in regurgitant lesions is to decrease regurgitant flow . All the patients with valvular heart disease undergoing non-cardiac sur­gery should get antibiotic prophylaxis to prevent infective endocarditis. AHA recommends ampicillin, 2 g I.M or I.V plus gentamicin 1.5 mg.kg -1 I.M or I.V 30 min. before procedure and 6 hrs later ampicillin 1 gm I.M or I.V. For patients allergic to penicillin, vancomycin 1 gm I.V is rec­ommended. For dental and endoscopic procedures, oral amoxicillin 2gm or cephalexin 2 gm or azithromycin 500 mg ,1 hr. before the procedure is given. Use of oral anti­coagulants in patients with mitral stenosis who have atrial fibrillation should be kept in mind. Tachycardia is detri­mental in both aortic and mitral stenosis. In MR and AR , it is advisable to maintain normal to high heart rate and mild vasodilatation to decrease the amount of regurgitant flow. In AS consideration should be given to the possibil­ity of CAD [11]


   Hypertension Top


Hypertension is the commonest cardiac disease all over the world. These patients are documented to have associated CAD, left ventricular dysfunction, renal failure which increase the perioperative risk. Hence it is advisable to control BP preoperatively. But this does not need sur­gery to be deferred for weeks, to achieve ideal blood pres­sure control, in patients with mild to moderate hyperten­sion. It is also important to evaluate for target organ dam­age. It is advisable to continue antihypertensives till the day of surgery. For patients with marked elevations of BP intra or post operatively should be managed by either nitroglyc­erine or sodiumnitroprusside by I.V. infusion. Intraarterial B.P. monitoring is recommended for such patients. Any factors of sympathetic stimulus should be avoided.


   Dysrrhythmias Top


Dysrrhythmias may be a marker of severity of un­derlying CAD or left ventricular dysfunction. A symptom­atic ventricular ectopics with stable haemodynamic pa­rameters do not need any treatment preoperatively. Simi­larly prophylactic treatment is not required in supraven­tricular tachycardia. In atrial fibrillation rate needs to be controlled. Perioperatively if they occur can be treated by calcium channel blockers ,beta blockers, adenosine.

Patients with conduction delay, LBBB do not re­quire pacing unless there is history of syncope. But in com­plete heart block, patients need to be paced. In patients on permanent pace makers ,electro cautery should be used with caution and for minimum period of time. The cau­tery plate should be as far as possible from the heart .Use of bipolar cautery decreases the risk of pacemaker dys­function. Use of magnet will turn pace maker into asyn­chronous mode , preventing unwanted inhibition.

The material submitted remains only an overview of the guidelines, which will continue changing from time to time, depending upon the evidence procured over a period of time. Also the techniques need to be tailored varying from patient to patient, surgical needs and the facilities available.

 
   References Top

1.Hall MJ, Owings MF. 2000 National Hospital Discharge Sur­vey. Hyattsville, MD: Department of Health and Human Ser­vices; 2002. Advance Data From Vital and Health Statistics, No. 329.  Back to cited text no. 1      
2.Goldman L, Caldera D, Nussbaum S, et al. Multifactorial index of cardiac risk in noncardiac surgical procedures. N Engl J Med 1977;297:845.  Back to cited text no. 2      
3.Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncar­diac surgery-executive summary. A report of the American Col­lege of Cardiology / American Heart Association Task Force on Practice Guidelines (Committee to update the 1996 guidelines on Preoperative Cardiovascular Evaluation for Noncardiac Sur­gery). Anesth Analg 2002; 94:1052.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]  
4.Detsky AS, Abrams HB, Forbath N , et al. Cardiac assessment for patients undergoing noncardiac surgery. A multifactorial clini­cal risk index. Arch Intern Med 1986; 146:2131.  Back to cited text no. 4  [PUBMED]    
5.Eagle K, Brundage B, Chaitman B, et al. Guidelines for perioperative cardiovascular evaluation for non-cardiac surgery. AHA/ACC task force report. J Am Coll Cardiol 1996; 27:910.  Back to cited text no. 5      
6.Stoelting RK, Dierdorf S. Ischemic heart disease. In:Stoelting RK, Dierdorf S, editors. Anesthesia and co-existing disease. 4th edition. Philadelphia. Churchill Livingstone 2002. p.2-8.  Back to cited text no. 6      
7.London MJ, Zaugg M, Schaub MC, et al. Preoperative beta­ adrenergic receptor blockade: physiologic foundations and clini­cal controversies. Anesthesiology 2004; 100:170.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]  
8.Dupuis JY, Labinaz M. Noncardiac surgery in patients with coronary artery stent : what should the anaesthesiologist know ? Can J Anaesth 2005;52:356.  Back to cited text no. 8  [PUBMED]    
9.Barash PG. Sequential monitoring of myocardial ischemia in the perioperative period. In:American Society of Anaesthesiologists Review Lectures. Atlanta: American Society of Anaesthesiology;2005.p.411.  Back to cited text no. 9      
10.Breen P, Park K W. General anesthesia versus regional anesthe­sia. Int Anesthesiol Clin 2002; 40:61.  Back to cited text no. 10      
11.Bonow RO, Carabello B, de LeonAC Jr, et al. Guidelines for the management of patients with valvular heart disease: Executive summary: a report of the American College of Cardiology/Ameri­can Heart Association Task Force on Practice Guidelines (com­mittee on management of patients with valvular heart disease). Circulation 1998;98:1949-84.  Back to cited text no. 11      




 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Introduction
    Risk stratification
    Evaluation
    History
    Examination
    Laboratory inves...
    Anaesthetic mana...
    Clinical risk fa...
    Surgery specific...
    Preoperative man...
    Preanaesthetic c...
    Premedication
    Intraoperative m...
    Managing intraop...
    Post operative m...
    Valvular heart d...
    Hypertension
    Dysrrhythmias
    References

 Article Access Statistics
    Viewed16362    
    Printed155    
    Emailed7    
    PDF Downloaded3755    
    Comments [Add]    

Recommend this journal