Preoperative Evaluation and Management

Preoperative Evaluation and Management - DR. JAYAL BHAGAT MD Anaesthesia PDMMC ,Amaravati

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Anesthetic drugs and techniques have profound effects on human physiology. Hence, a focused review of all major organ systems should be completed prior to surgery.

The goals of preoperative evaluation are to reduce patient risk and the morbidity of surgery(with the premise that it will modify patient care and improve outcome)

This ultimately allows the anaesthesiologist to formulate an appropriate anaesthetic plan with contingencies to deal with patients comorbidity associated complications and/or need to optimize patient prior to surgery.It is also a medicolegal document.

The process should be used to educate the patient about anesthesia and the perioperative period, answer all questions, and obtain informed consent.

History taking Always listen to the patient they might be telling you the diagnosis.

(Sir William Osler 1849 - 1919)

APPROACH TO THE PATIENTName Age /sexAddress Presenting complains - Diagnosis & proposed surgeryh/o of presenting complains :- duration /severity mode of onset Progression Associated complaints

Past illnessPersonal historyFamily history Drugs & allergies Prior surgeries and prior experience with anaesthetics(e.g. PONV, malignant hyperthermia )General examination Systemic examination Lab investigation assessment

Nil by mouthCurrent comorbidities(acute or chronic )Risk classification ASA Physical status classification

medical statusASA Inormal healthy patient without organic, biochemical, or psychiatric diseaseASA IImild systemic disease with no significant impact on daily activity e.g. mild diabetes, controlled hypertension, obesity .ASA IIIsevere systemic disease that limits normal activity. Significant impact on daily activity. Probable impact on Anesthesia & Surgery e.g. angina, COPD, prior myocardial infarctionASA IVSEVERE disease that is a constant threat to life or require intensive therapy. Serious limitation of daily activity. Major impact on Anesthesia & Surgery e.g. CHF, unstable angina, renal failure ,acute MI, respiratory failure requiring mechanical ventilationASA Vmoribund patient who is equally likely to die with or without surgery e.g. ruptured aneurysmASA VIbrain-dead patient whose organs are being harvested

ASA Physical Status Classification System For emergent operations, you have to add the letter E after the classification.

ASSESSMENT SYSTEM WISE APPROACH

Respiratory systemCardinal symptoms Cough Types dry/prroductive/paroxysmal/bovine

SputumAmount Colour Consistensy Odour

Dyspnoea Causes Physiologiacal anemia ,exercise, mountainersRespiratory asthama ,COPD,pulmonary edema pneumothorax ,pleural effusionCardiac acute MI,cyanotic heart disease, valvular heart dieasesMetabolic acidosisCNS GBS, polio, myasthenia gravis

Hemoptysis h/o smoking, tobacco use,alcohol

PulmonaryA screening evaluation should include questions regarding the history of tobacco use, shortness of breath, cough, wheezing, stridor, and snoring or sleep apnea. The patient should also be questioned regarding the presence or recent history of an upper respiratory tract infection.Auscultation should be used to detect decreased breath sounds, wheezing, stridor, or rales.

Cardiovascular systemCardinal symptoms Dyspnoea on exertion Chest painPalpitation SyncopeCough Hemoptysis

NYHA Classification

Class I: no limitation of physical activity; ordinary activity does not cause fatigue, palpitations, or syncopeClass II: slight limitation of physical activity; ordinary activity results in fatigue, palpitations, or syncopeClass III: marked limitation of physical activity; less than ordinary activity results in fatigue, palpitations, orsyncope; comfortable at restClass IV: inability to perform any physical activity without discomfort; symptoms at rest

Metabolic equivalent1Eating, working at a computer, dressing2Walking down stairs or in your house, cooking3Walking 1-2 blocks4Raking leaves, gardening 5Climbing 1 flight of stairs, dancing, bicycling 6Playing golf, carrying clubs 7 Playing singles tennis 8Rapidly climbing stairs, jogging slowly 9Jumping rope slowly, moderate cycling 10Swimming quickly, running or jogging briskly 11Skiing cross country, playing full-court basketball 12Running rapidly for moderate to long distances

Other important symptomsFever HeadacheSyncopeConvulsionsConstipation /diarrhoeaLoss of weight H/o heartburns

Past illnessh/o of Hypertension ,DM ,TBh/o of Drugs allergyh/o of surgery & exposure to anaesthesiaPrevious hospitalization

Personal h/o - smoking,tobacco ,alcoholFamily h/o HT,DM,ConsnguinitySickle cell disease ,thalassaemia,heamophilia

General examinationTemperaturePulseRespiratory rateBlood pressurepallor / oedema /lymphedenopathy/icterus/cyanosis/clubbing

PulmonaryInspection shape of chest/ movementType of breathing respiratory rate /rhythmPercussion Dull note consolidation/fibrosisStony - pleural effusionTympany pneumothorax /emphysemaAuscultation should be used to detect decreased breath sounds, wheezing, stridor, or rales.

CVS inspection Precordium - bulging /flattenedApex impulseDilated veins

Palpation & percussion

Auscultation Mitral area5th intercostal space just inside the midclavicular lineTricuspid Lower end of sternum near ensiform cartilageaortic2nd right intercostal spacepulmonary2nd left intercostal space

Neurologic SystemA screening of the neurological system in the apparently healthy patient can mostly be accomplished through simple observation. The patient's ability to answer health history questions practically ensures a normal mental status. Questions can be directed to exclude the presence of ;Increased intracranial pressure, Cerebrovascular disease, Seizure history, Preexisting neuromuscular disease, Nerve injuries,Spinal cord Injury; Disorders of NM junction e.g myasthenia gravis, muscular dystrophies

Power ToneAtaxiaInvoluntary movementsReflexes superficial /deep

Predictors of difficult intubation ( 4 M )

Mallampati

Measurements 3-3-2-1 or 1-2-3-3 Patient s fingers Movement of the Neck

Malformations of the Skull Teeth Obstruction Pathology

Class I = visualize the soft palate, fauces, uvula, anterior and posterior pillars.

Class II = visualize the soft palate, fauces and uvula.

Class III = visualize the soft palate and the base of the uvula.

Class IV = soft palate is not visible at all.

Mallampati

Measurements 3-3-2-13 Fingers Mouth Opening

3 Fingers Hypomental Distance. (3 Fingers between the tip of the jaw and the beginning of the neck (under the chin)

2 Fingers between the thyroid notch and the floor of the mandible (top of the neck)

1 Finger Lower Jaw Anterior sublaxation

Movement of the Neck

Skull (Hydro and Microcephalus)

Teeth ( protruded, & loose teeth. Macro and Micro mandibles)

Obstruction (obesity, short Bull Neck & swellings around the head and neck)

Pathology (Craniofacial abnormalities & Syndromes e.g. Treacher Collins, Goldenhar's, Pierre Robin syndromes)

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Malformation of the skull

Treacher Collins (mandibulofacial dysostosis)

Pierre Robin( hypertelorism; and external and middle ear deformities)

Cardiovascular SystemWhen screening a patient for cardiovascular disease prior to surgery, the anesthesiologist is most interested in recognizing signs and symptoms of uncontrolled hypertension and unstable cardiac disease such as ;myocardial ischemia, congestive heart failure, valvular heart disease, andsignificant cardiac dysrhythmiasExercise tolerance is one of the most important determinants of perioperative risk and the need for further testing and invasive monitoring.Inability to walk 4 blocks (1 block is100-200 meters) or climb 2 flights of stairs is defined as poor exercise tolerance.(this doubles your risk of adverse cardiovascular outcomes)

Endocrine System

Each patient should be screened for endocrine diseases that may affect the perioperative course:diabetes, thyroid disease, parathyroid disease, endocrine-secreting tumors, and adrenal cortical suppression.

Issues Related to Surgery :

significant blood loss; respiratory compromise; positioning

Laboratory TestingReasonable testingpositive finding in history and physical exam.need for baseline value in anticipation of significant change due to surgery and medical interventionpatient's inclusion in population at higher risk

Preoperative PreparationAnesthetic indications: -Anxiolysis, sedation and amnesia. e.g. benzodiazepine(diazepam ,lorazepam) -Analgesia e.g narcotics-Drying of airway secretions e.g atropine,glycopyrrolate,scopolamine-Reduction of anesthetic requirements ,Facilitation of smooth induction -Patients at risk for GE reflux :ranitidine ,metoclopramide , sodium citrate

Surgical indications: -Antibiotic prophylaxis for infective endocarditis. -Prophylaxis against DVT for high risk patients : low-dose heparin or aspirinintermittent calf compression, or warfarin.

Co-existing Disease indications: Some medications should be continued on the day of surgery e,g B blockers, thyroxine. Others are stopped e.g oral hypoglycemics and antidepressants .Steroids within the last six months may require supplemental steroids

INGESTED MATERIALMINIMUM FASTING PERIOD, APPLIED TO ALL AGES (hr)Clear liquids2Breast milk4Infant formula6Nonhuman milk6Light meal (toast and clear liquids)6

Fasting Recommendations

Preop preparation for DMClassic NonTight Control RegimenAim: To prevent hypoglycemia, ketoacidosis, and hyperosmolar states.Protocol:1. On the day before surgery, the patient should be given nothing by mouth (NPO) after midnight; a 13-ozglass of clear orange juice should be at the bedside or in the car for emergency use.2. At 6 AM on the day of surgery, infuse a solution of intravenous fluids containing 5% dextrose through plastic cannulas at a rate of 125 mL/hr/70 kg body weight.3. After starting the intravenous infusion, give half the usual morning insulin dose (and the usual type of insulin)subcutaneously.4. Continue 5% dextrose solutions through the operative period and give at least 125 mL/hr/70 kg body weight.5. In the recovery room, monitor blood glucose concentrations and treat on a sliding scale.

Tight Control Regimen 1Aim: To keep plasma glucose levels at 79 to 120 mg/dL. Maintenance of such levels may improve wound healing and prevent wound infections, improve neurologic outcome after global or focal CNS ischemic insults, or improve weaning from cardiopulmonary bypass.Protocol:1. On the evening before surgery, determine the preprandial blood glucose level.2. Through a plastic cannula, begin an intravenous infusion of 5% dextrose in water at a rate of 50 mL/hr/70 kgbody weight.3. Piggyback an infusion of regular insulin (50 units in 250 mL or 0.9% sodium chloride) to the dextrose infusion with an infusion pump Before attaching this piggyback line to the dextrose infusion,flush the line with 60 mL of infusion mixture and discard the flushing solution. This approach saturates insulin binding sites on the tubing.4. Set the infusion rate by using the following equation: Insulin (U/hr) = plasma glucose (mg/dL)/150. (Note: The denominator should be 100 if the patient is taking corticosteroids, e.g., 10 mg of prednisolone a day or its equivalent, not to include inhaled steroids, or has a body mass index of 35.)

5. Repeat blood glucose measurements every 4 hours as needed, and adjust insulin appropriately to obtain blood glucose levels of 100 to 200 mg/dL.6. On the day of surgery, intraoperative fluids and electrolytes are managed by continued administration of nondextrose-containing solutions, as described in steps 3 and 4.7. Determine the plasma glucose level at the start of surgery and every 1 to 2 hours for the rest of the 24-hour period. Adjust the insulin dosage appropriately.

Tight Control Regimen 2

Aim: Same as for Tight Control Regimen 1.Protocol:1. Obtain a feedback mechanical pancreas and set the controls for the desired plasma glucose regimen.2. Institute two appropriate intravenous lines.

Sliding scale for DM

Steroids in anesthetic consideration