High Risk Cases

7/28/2019 High Risk Cases

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PREOPERATIVE PREPARATION

AND INTRAOPERATIVEMANAGEMENT OF HIGH RISK

CASES


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Aim of Preoperative Planning

Issues that should be discussed with patient

preoperatively

Important coexisting medical diseases that

increases the morbidity and mortality of surgery

Non-specific factors that may increase the

operative risk for patients undergoing surgery


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MAJOR CARDIAC RISK FACTORS

MI within previous 3 or 6 months

Unstable angina

Untreated cardiac failure

Significant aortic valve stenosis

Untreated hypertension


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RELATIVE CARDIAC RISK FACTORS

Prior MI

Jugular vein distension

Non-sinus rhythm

Ventricular ectopic beats / min

Age > 70 years

Surgery > 3 hours

Emergency surgery

PaO2 < 60 mm Hg, PaCO2 > 50 mm Hg

Chronic liver impairment


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PREOPERATIVE ASSESSMENT FOR

CARDIOVASCULAR SYSTEM

Chest X-ray

ECGStress ECG

Isotopic scanning

Echocardiography

Coronary angiography


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ASSOCIATED RISK WITH PREVIOUS

PATHOLOGY

PREVIOUS PATHOLOGYASSOCIATED RISK

OF MI

No previous pathology 5%

Acute MI > 6 months previously 6%

MI 3-6 months ago 10-15%

Infarction < 3 months ago 30%


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GRADING SYSTEM FOR

ASSESSMENT OF ANGINA

CLASS ASSESSMENT OF ANGINA INVESTIGATIONRISK OF

SURGERY

Class 1Angina with strenuous

exerciseExercise ECG None

Class 2Angina with moderate

exerciseExercise ECG None

Class 3

Angina after climbing one

flight of stairs or walkingone block

Coronary

angiography and

coronary artery

surgery

High incidence of

MI

Class 4 Angina with any exercisePrior to elective

surgery

High incidence of

mI


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MANAGEMENT IN PATIENTS WITH

KNOWN OR SUSPECTED ISCHEMIC

HEART DISEASEPreoperative preparation and medication

Optimal preoperative anti-ischemia and

antihypertension therapy

Pharmacological and psychological attempt to

decrease anxiety

Drugs used for medical management of patients

with ischemic heart disease are continued

throughout the perioperative periods


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Intraoperative Management

The goal to prevent myocardial ischemia is achieved

by maintaining the balance between myocardial

oxygen delivery and myocardial oxygen

requirement.


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INTRAOPERATIVE EVENTS THAT

INFLUENCE THIS BALANCE

Decreased oxygen delivery

Decreased coronary blood flow

Decreased oxygen content

Increased preload (wall tension)

Increased oxygen requirement

Sympathetic nervous system stimulation


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INDUCTION OF ANESTHESIA

Ketamine should be avoided

Fast intubation

Continuous Infusion of nitroglycerine

0.25 to 1.0 g/kg/min I/V


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MAINTENANCE OF ANESTHESIA

Choice of Muscle Relaxant

Monitoring

ECG

Pulmonary artery catheter

Transesophageal echocardiography

Intraoperative treatment of myocardial ischemia


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HYPERTENSION - PREOPERATIVE

AND INTRAOPERATIVE AIM

Assessment and optimization of blood

pressure control

Assessment of associated pathology

Anesthetic management

Postoperative management


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HYPERTENSION

Intraoperative management

Volatile anesthetics are useful

Infusion of nitroprusside

Labetalol


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JAUNDICE (HEPATIC FAILURE)Complications that jaundiced patient associated

with are

Renal dysfunction

Sepsis

Coagulation disturbance

Poor wound healing


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PREOPERATIVE MEASURE TO

REDUCE THESE COMPLICATIONSStrict perioperative control of fluid and

electrolyte balance

Preoperative volume expansion

Antibiotic prophylaxis

Assessment of coagulation statusAssessment of nutritional status

Perform baseline investigation


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ANAESTHESIA

Induction of Anesthesia

Muscle Relaxant

Monitoring


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RENAL SYSTEM

Perform routine urinalysis

Urea / electrolytes

Serum creatinine, albumin, serum & urinary osmolality

Perform USG of renal tract

Plain abdominal X-ray

IVU (intravenous urogram)

DTPA / DMSA

In critically ill patients, measure urinary output hourly

Insert urinary catheter preoperatively


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ASSOCIATED MEDICAL PROBLEMS

OF PATIENT WITH CHRONIC RENALFAILURE

Cardiovascular

Acid base and metabolic

Immune system

Coagulation

Miscellaneous


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INTRAOPERATIVE MANAGEMENT

Neuromuscular blocking drugs like

mivacurium, atracurium, lisatracurium

Blood loss may be alarming

Ventilation


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FLUID MANAGEMENT

If patient is anuric ringer lactate solution or other K+containing fluids should not be administered

Administration of balanced salt solution 3-5 ml/kg/hr IV is

often recommended

Without adequate intravascular fluid replacement,

mannitol or furesemide are discouraged

If fluid replacement does not restore urine output a

diagnosis of congestive heart failure may be considered.

Dopamine 0.5 to 3.0 g/kg/min IV increases renal blood

flow, the GFR and urine output


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RESPIRATORY SYSTEMRisk factors which increase the incidence of

postoperative pulmonary complications

History

Examination

Surgery and Anesthesia


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PREOPERATIVE MEASURES TO

REDUCE POSTOPERATIVE

PULMONARY COMPLICATION

Preoperative bronchodilator therapy

Preoperative chest physiotherapyCessation of smoking 68 weeks prior to major

surgery

Use of an incentive spirometer and instruction intechniques of deep breathing and coughing

improves pulmonary function


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PREOPERATIVE MEASURES TO

REDUCE POSTOPERATIVE

PULMONARY COMPLICATIONRegular assessment of pulmonary function

Pain, insert an epidural catheter at the time of

surgery

Regional anesthetic techniques such as local nerve

block, brachial block or spinal anesthetic

If an acute upper or lower respiratory tract infection

is there then postpone elective procedure for at least

2 weeks following resolution

Prophylactic antibiotics


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PREOPERATIVE ASSESSMENT OF

COMPROMISED PULMONARY

FUNCTIONProper history and examination

Chest X-ray

ECGBlood gas analysis

Spirometric test

Forced Vital Capacity (FVC) Forced Expiratory Volume in Liters (FEV1)

Peak Flow Rate (PFR)

FEV1 / FVC ratio


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ASTHMA

Asthma is a syndrome of heightened bronchial

reactivity resulting in airflow obstruction of

variable severity


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PREOPERATIVE AIM

TYPE TREATMENT

Mild asthma

(no previous hospitalization)

Maintain routine therapy and

administer selective 2 agonist

(salbutamol) via aerosol or nebulizer

prior to surgery

Moderate asthma

(some functional impairment

routine use of bronchodilator)

Maintain routine therapy and

administer selective 2 agonist

(salbutamol) prior to surgery

Severe asthma

(significant impairment, current

brochoconstriction)

Corticosteroids should be used (e.g.

hydrocortisone 13 mg/kg/2 hour prior

to surgery in addition to inhaled 2

agonist therapy)


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INTRAOPERATIVE MEASURE TO REDUCE

INCIDENCE OF POSTOPERATIVE

PULMONARY COMPLICATIONS

Use minimally invasive surgery (laparoscopic)

techniques when possible

Consider use of regional anesthesia

Avoid use of long-acting neuromuscular blocking

drugsAvoid surgical procedures likely to require more

than 3 hours


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ENDOCRINE SYSTEM

Diabetes

Incidence: ~2.5% of the population have diabetes

>90% have non-insulin dependent diabetes mellitus

(NIDDM or type II diabetes)


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ASSESSMENT OF COEXISTENTPROBLEM

Cardiovascular system

Hypertension

Peripheral vascular disease

Renal disease


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MANAGEMENT OF DM

MINOR IMMEDIATE / MAJOR

Controlled by diet No specific precaution

Measure blood glucose 4

hourly, if >12 mmol/lt start

dextrose insulin infusion.

Avoid IV dextrose

Controlled by oral

agents

Omit medication on

morning of operation and

start when eating normally

ostoperatively

Omit medications and

monitor blood glucose 1-2

hourly, if >12 mmol/lt start

dextrose insulin infusion

Controlled by

insulin

Unless very minor procedure (omit insulin when nil by

mouth) give dextrose-insulin infusion during surgery

and until eating normally postoperatively


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CONTINUOUS INTRAVENOUS INFUSION OF

REGULAR INSULIN DURING THEPERIOPERATIVE PERIOD

Mix 50 units of regular insulin in 500 ml of normalsaline (1 unit/hr = 10 ml/hr)

Initiate intravenous infusion at 0.5-1.0 unit/hour

Provide sufficient glucose (5-10 g/hour) and

potassium (2-4 mEq/L)


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< 80 mg/dL

Turn intravenous infusion off for 30 min

Administer 25 ml of 50% glucose

Remeasure the blood glucose concentration in

30 min

80-120 mg/dL Decrease insulin infusion rate by 0.3 unit/hour

120-180 mg/dL No change in insulin infusion rate

180-220 mg/dL Increase insulin infusion rate by 0.3 unit/hour

>220 mg/dL Increase insulin infusion rate by 0.5 unit/hour

Measure blood glucose concentration as necessary every

(1-2 hours) and adjust glucose infusion rate accordingly.


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THYROIDHyperthyroidism

To render hyperthyroid patient euthyroid prior to

surgery

Emergency surgery

Esmolol 100-300 g/kg/min IV until heart rate < 100 bpm


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ELECTIVE SURGERY

Oral administration of a adrenergic antagonist

Antithyroid drugs

Antithyroid drugs + potassium iodide

Potassium iodide plus a adrenergic receptor

antagonist


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COMPLICATION THAT MAY OCCUR

DURING INTRAOPERATIVE PERIODS WITHCONTROLLED HYPERTHYROIDISM

Thyroid storm

Precipitation of angina, myocardial

infarction or cardiac failure

Tachyarrhythmia


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MANAGEMENT

Intravenous administration of antithyroid drug

Indwelling arterial monitoring

Sedating premedication to allay anxiety

Avoidance of drugs that may provoke tachycardia,

such as ketamine, pancuronium and atropine

Use of blockade to control heart rate

Adequate depth of anesthesia to ablate noxious

stimuli

Good postoperative pain control


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HYPOTHYROIDISM

Management

Render euthyroid before surgery by oral

administration of T4


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COAGULATION STATUS

Special assessment is necessary in patients

with a history of bleeding e.g. epistaxis,

menorrhagia, petechiae, purpura or ecchymosis.

Points to be noted in history are:

Alcoholism

Liver disease

Administration of corticosteroids or antiplatelet

drugs (e.g. aspirin, dipyridamide)

Family history of bleeding


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SCREENING TEST

Vascular and platelet defect

Clotting mechanism

Fibrinolysis in DIC

Elderly patient (more than 60 years)


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PAEDIATRIC SURGERY

Physiology

Respiratory system

Cardiovascular system

Fluid requirement

Renal function

Hematology

Thermoregulation

Pharmacology

Anesthetic requirement

Muscle requirement

Pharmacokinetic

Monitoring

We have to take special considerations


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PROPHYLAXIS

DVT

Prophylactic measures

Cessation of smoking

Avoidance of pressure on the venous intima

Adequate perioperative fluid hydration

Early mobilization

Use of graduated elastic compression stocking

Physical method Electrical calf stimulation, pneumatic

leg compression


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DVT DRUG PROPHYLAXIS

Indicated in selective patients

Most frequently used drug regimen

Low molecular weight heparin single injection each

day may be given 12 hourly before surgery

Low dose subcutaneous heparin 5000 IU given 2

hours before surgery

Dextran 40 to 70 (500 ml IV preoperatively)

Antibiotics

Renal function


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High Risk Cases

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