Post on 14-Apr-2017
PRE-ANESTHETIC CHECKUP
Presenter: Dr. Rashmit Shrestha
1st year RESIDENT Moderator: Prof. Dr. Md Aslam
ANESTHESIAAnesthesia (from Greek an “without” aesthesis “sensation”)The components of the anesthetic state include • unconsciousness• loss of memory• lack of pain• immobility and attenuation of autonomic
responses to noxious stimulation.
PREOPERATIVE EVALUATION
• Defined as the process of clinical assessment that precedes the delivery of anesthesia for surgery and for non surgical procedures.
• It consists of the consideration of information of multiple sources that may include the patient’s interview, medical records, physical examination
and findings from medical tests and evaluations.
GOALS
• To ensure that the patient is in the best(optimal) condition.
• Patients with unstable symptoms should be postponed for optimization prior to elective surgery.
• Anesthetic drugs and techniques have profound effects on human physiology. Hence, focused review of all major organ system should be done prior to elective surgery.
OBJECTIVES
• Doctor patient relationship.
• Patient data.
• Anesthetic plan
• Patient consent
STEPS OF PREOPERATIVE VISIT
1. Problem identification
2. Risk assessment
3. Preoperative preparation
4. Plan of anesthetic technique.
Clinical Examinations
• Phase 1: History taking-– Gathering of information,
• Phase 2: Physical examination-– Objective findings,
• Phase 3: Explanation-– Information giving & decision making,
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Phase 1: History taking• Demographic details,• Presenting complaint (PC),• History of presenting complaint (HPC),• Past medical history (PMH),• Previous anesthetic history-any h/o difficult intubation,any h/o allergy at
that time• Drug history (DH),• Family history (FH),• Social history (SH),• Systemic enquiry (SE),
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Demographic details
• Date & time of examination,• Patient’s name, DOB, Age, weight & address,• Source of referral,• Doctor’s name,• Source of history: patient, relative, care taker
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Physical examination:
• General exam:– Blood pressures, Pulse, Respiration, Temp
(clinical asses),– Jaundice, pallor, cyanosis , clubbing & edema,
hydration status.– Weight (kg),
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Systemic examination: Cardiac & Vascular examination, Pulmonary examination,
Special examination: Airway assessment, Peripheral venous access, Spinal examination,
Airway
• Incidence of difficult intubation reported to range between 0.13 – 5.9%
• It can be predicted and expert anaesthsiologist is called for the case.
• Evaluation is the first step in management of difficult intubation.
AIRWAY CLASSIFICATION SYSTEM
MALLAMPATI SCORECLASS DIRECT VISULAISATION OF
AIRWAY1 Full view of Soft Palate, fauces,
uvula, tonsillar pillars2 Soft palate, fauces ,upper
portion of uvula3 Soft palate ,uvular base
4 Hard palate only.
LARYNGOSCOPIC VIEWCormack lehaneCLASS LARYNGOSCOPIC VIEW
1 Entire glottic
2 Posterior commisure
3 Tip of epiglottis
4 No glottic structure.
Airway evaluation
• Mentothyroid distance : normal 6 cm.• Mentosternal distance : normal 15 cm• Mentohyoid distance : normal 3 FB• Neck movement: flexion and extension of
neck, history of radiation• Nasal cavity
Thyromental distance
Difficult intubation
• Mouth opening less than 3 cm.• Limitation of neck movement• Micrognatia• Macroglossia• Protusion of teeth• Short neck• Morbid obesity
Airway Examination
Normal – Opens mouth normally (Adults: greater than 2 finger widths or 3 cm)– – Able to visualize at least part of the uvula and tonsillar pillars with
mouth wide open & tongue out (patient sitting)– – Normal chin length (Adults: length of chin is greater than 2 finger
widths or 3 cm)
– Normal neck flexion and extension without pain / paresthesias
Airway Examination
Abnormal – Small or recessed chin – Inability to open mouth normally – Inability to visualize at least part of uvula
or tonsils with mouth open & tongue out –High arched palate –Tonsillar hypertrophy –Neck has limited range of motion – Low set ears – Signficant obesity of the face/neck
Airway assessment: predictive testsSensitivity = 50-60%
• Mallampati modified test:Visibility of pharyngeal structures.• Patil test:Thyro-mental distance <6.5cm• Mandibular protrusion:Class C : inability to protrude lower incisors beyond the upper.• Wilson test.• Radiological assessment of the mandible and cervical spine.
WILSON RISK TEST
medical status mortalityASA I normal healthy patient without organic, biochemical,
or psychiatric disease0.06-0.08%
ASA II mild systemic disease with no significant impact on daily activity e.g. mild diabetes, controlled hypertension, obesity .
Unlikely to have an impact0.27-0.4%
ASA III severe systemic disease that limits activity e.g. angina, COPD, prior myocardial infarction
Probable impact 1.8-4.3%
ASA IV an incapacitating disease that is a constant threat to life e.g. CHF, unstable angina, renal failure ,acute MI, respiratory failure requiring mechanical ventilation
Major impact 7.8-23%
ASA V moribund patient not expected to survive 24 hours e.g. ruptured aneurysm
9.4-51%
ASA VI brain-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.
Cardiovascular system
• Pulse: rate, rhythm, character and volume,
• Blood pressure (BP),
• Jugular venous pulse (JVP): height and character,
• Ankle edema: presence or absence,Dr Resham B Rana, MD 26
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• Inspection: – any scar, abnormal vessels, lumps, chest shape, apex beat-
position,–
• Palpation (localize technique): – confirm apex beat, character, presence of thrills &
peripheral pulses on both sides,
• Percussion (technique): – precordium- size of heart,
• Auscultation (technique): – heart sounds, murmur,
H/O TO REVIEW OF THE ORGAN SYSTEM
CVS Symptoms of the following problems sought
in all patients.Ischaemic heart diseaseHTNHeart failureConduction defect and arrythmiaPeripheral vascular disease
Patient with h/o of MI are greater risk of perioperative reinfarction, the incidence of which is related to the time interval between surgery and infarct.
The presence of unstable angina has been associated with a high perioperative risk of MI.
The presence of active congestive heart failure has been associated with an increased incidence of perioperative cardiac morbidity.
REVISED CARDIAC RISK INDEX(UNDERGOING ELECTIVE MAJOR NON CARDIAC PROCEDURES)
1. High risk type of surgery2. History of ischaemic heart disease3. History of congestive heart failure4. History of cerebrovascular disease5. Preoperative treatment with insulin6. Preoperative serum creatinine>2mg/dl
Rates of major complications with 0,1,2 or 3 of these factors are 0.5,1.3,4 and 9% respctively.
The American heart association /American College of cardiology task force on perioperative evaluation of cardiiac patient undergoing noncardiac surgery has definded three risk groups-1 Major2 Intermediate3 MinorThey indicate that recent MI(<30 days)places patients in the group of highest risk,after that period ,a prior MI places the patient in the group at intermediate risk.
CLINICAL PREDICTORS OF INCREASED PERIOPERATIVE CVS RISK(MI,CHF,DEATH)
• MAJOR
Unstable coronary sydromesRecent MI with evidence of important ischaemic risk by clinical symptoms or noninvasive study.Unstable or severe anginaDecompensated congestive heart failureSignificant arrythmiasHigh grade AV blockSymptomatic ventricular aarythmias in the presence of underlying heart disease.Supraventricular arrythmias with uncontrolled ventricular rate.Severe valvular disease.
• INTERMEDIATE
Mild angina pectorisPrior MI by history or pathological Q wave Compensated or prior CHF.Diabetes mellitus.
• MINOR
Advanced ageAbnormal ECG (Left ventriculay hypertrophy,LBBB,ST-T abnormalities)Rhythm other than sinus(e.g- AF)Low functional capacity (e.g- inability to climb one flight of stairs )History of strokeUncontrolled systemic HTN
Clinical Predictors of Increased Perioperative Cardiovascular Risk
• Functional Capacity– Metabolic equivalents– 1 MET – Can you take care of yourself? Eat, dress,
use the toilet? Walk a block or two on level ground 2-3 MPH
– 4 METs – Do light work around the house like dusting or washing the dishes? Climb a flight of stairs?
– >10 METs – Participate in strenuous sports like swimming, singles tennis, football?
Clinical Predictors of Increased Perioperative Cardiovascular Risk
• Functional Capacity– Perioperative cardiac and long-term risks are
elevated in patients unable to obtain 4-MET demand
– www.1000takes.com
HYPERTENSON Untreated and poorly controlled HTN may lead
to exaggerated cardiovascular responses during anesthesia.
Both HTN and hypotension can be precipitated,which increase the incidence of both mycardial and cereberal ischaemia.
BLOOD PRESSURE
CATEGORY SBP(MM HG) DBP(MM HG)
Optimal <120 and <80
Normal <130 and <85
High Normal 130-139 or 85-89
Hypertension
Stage 1 140-159 or 90-99
Stage 2 160-179 or 100-109
Stage 3 ≥180 or ≥110
There is controversy regarding a trigger to delay or cancel a surgical procedure in a patient with untreated or inadequately treated hypertension.
It is less clear in patients with blood pressure above 180/100 mm hg ,although no absolute evidence exists that postponing surgery will reduce risk.
In the absence of end organ changes,such as renal insufficency left ventricular hypertrophy with strain,the benfits of optimizing BP must be weighed against the risk of delaying surgery.
• Aggressive treatment of BP is associated wih increased reduction in long term risk,although the effect diminishes in all but in diabetic patient diastolic pressure is reduced to 90mmhg.
• Patient with BP of >180 mm hg systolic or 110 hg diastolic are prone to develope perioperative MI, venticular dysarrythmias, and lability in BP.
CORONARY ARTERY DISEASEFor those patients without overt symptoms or history the probability of CAD varies with the type and number of atherosclerotic risk factor present.
Pheripheral arterial disease has been associated with CAD in multiple studies.
There is a high incidence of both silent MI and myocardial ischaemia in diabetics.
CARDIAC RISK STRATIFICATION FOR NONCARDIAC SURGICAL PROCEDURES IN PATIENTS WITH KNOWN
CORONARY ARTERY DISEASE
• HIGHReported cardiac risk often> 5%1. Emergency major operations,particularly in the
elderly2. Aortic and major vascular3. Peripheral vascular4. Anticipated proloned surgical procedures
associated with large fluid shifts and/or blood loss.
• INTERMEDIATEReported cardiac risk gnerally <5%1. Carotid endarterectomy2. Head and neck3. Intraperitoneal and intrathoracic4. Orthopedic5. prostate
• LOWReported cardiac risk generally < 1%1. Endoscopic procedures2. Superficial procedures3. Cataract Surgery4. Breast Ambulatory procedures
• Coronary Angiography
• Evidence of adverse outcome from non-invasive test• Angina unresponsive to therapy• Unstable angina, especially with intermediate or high
risk surgery• Equivocal noninvasive test in high clinical risk patient
undergoing high risk surgery
Pulmonary DiseasePulmonary complications occurs more frequently than cardiac complications (5-10% incidence )Perioperative complications includes: 1. Aspiration2. Atelectasis 3. Pnuemonia 4. Bronchitis5. Bronchospasm 6. Hypoxemia7. AE COPD8. Respiratiory Failure requiring Mechanical Ventilation
Pre-operative Investigations• General: 1- Complete Blood Count and Hemoglobin
Concentration 2- Clotting screen 3- Liver function. 4- ECG 5- Echocardiogram Abnormal ECG, ischemic heart….
6- Chest x-ray 7- Blood sugar level 8-Electrolytes, Blood Urea Nitrogen/ Creatinine
Preparation For Anesthesia
• Continuing Current Medications/ Treatment of Coexisting Diseases
It is the RESPONSIBILITY of the anesthesiologist to instruct patients regarding which medications to take and which to hold preoperatively.
Instruct Patients to take the medications with small sips of water, even if fasting!
Medications to be Continued on the day of Surgery1. Antihypertensives except ACE Is and ARBs2. Cardiac medications e.g ᵦ- blockers, digoxin3. Antidepressants, anxiolytics and other psychiatric medications4.Thyroid medications5.Birth control pills, eye drops, heartburn or reflux medications, narcotics, anticonvulsants, asthma medications, Steroids, Statins,
AspirinConsider selectively continuing aspirin in patients where the risk of cardiac events is felt to exceed the risk of major bleeding.if reversal of platelet inhibition is necessary,
stop aspirin at least 3 days before surgery.Do not discontinue aspirin if patients who
have drug eluting coronary stents until they have completed 12 months of dual anti platelet therapy.
Thienopyridines (Clopidogrel and Ticlopidine)• Patients having Cataract Surgery – Do not need
to stop.• If reversal of platelet inhibition is necessary,
then clopidogrel must be stopped 7 days before surgery (Ticlopidine – 14 days)
• Do not discontinue Thienopyridines in Pt. who have drug eluting stents before 1 year.
Medications to be discontinued
• Topical medications e.g creams and ointments• Oral hypoglycemic agents ( on the day of Sx)• Diuretics (on the day of Sx except Thiazide)• Sildenafil ( Viagra) of similar drugs –
discontinue 24 hrs before Sx.• NSAIDS – discontinue 48 hrs before Sx.• Warfarin ( Coumadin) discontinue 4 days
before Sx
NPO guidelinesSubstance Maximum Hours of Fasting
Solid 8
Formula 6
Cow’s Milk 6
Citrus Juice 6
Breast milk 4
Clear liquids 2
Pharmacological Agents to Reduce the risk of Pulmonary Aspiration
• Histamine – 2 Receptor Antagonist : block the ability of histamine to induce secretion of gastric fluid with high hydrogen concentrations e.g. Cimetidine, Ranitidine, Famotidine
• Antacids – neutralize the acid in gastric contents• Proton pump inhibitors: supress gastric acid
secretion by binding proton pump of the parietal cell
• Gastrokinetic Agents : Metoclopramide- Dopamine antagonist.
Psychological Preparation
• Preoperative visit and interview with the patient and family members,
• The anesthesiologist should explain anticipated events and the proposed anesthetic management in an effort to reduce anxiety and diminish apprehension.
Pharmacological preparation
• To relief anxiety and production of sedation• Prophylaxis against allergic reactions e.g. to
latex• Prevention of Autonomic reflexes mediated
through the vagus nerve.• Prevention of nausea and vomiting.
Benzodiazepines
• Produces anxiolysis, amnesia and sedations e.g. Diazepam, Midazolam, Lorazepam
Diphenhydramine : histamine-1 receptor antagonist, blocks the peripheral effects of histamine, it has sedative, anticholinergic and antiemetic activity.Anticholinergics : (Atropine, glycopyrolate, scopolamine)
1. Antisialogogue effect2.sedation and amnesia3. Vagolytic effect
Antibiotic Prophylaxis• Cephalosporins are the most popular antibiotics
because they cover skin microbes,• For intestinal Sx, anaerobic and Gram negative
coverage is needed.• Antibiotics must be administered within 1 hr
prior to incision except : Vancomycin should be given 2hr prior to incision when tourniquet is used, the antibiotics should
be adminstered prior to its inflation.
Summary of the Patient Preparation
• The anesthesiologist who takes the time to adequately prepare the patient medically and psychologically for anesthesia and surgery will find that their job of caring for the patient intraoperative becomes easier, and they are more likely to have a positive outcome as well as a satisfied patient.
Thank You
References
• 1. CLINICAL ANESTEHESIOLOGY, Morgan & Mikail’s, 5TH Edition, Page № 295-307
• 2. Clinical Anesthesia, Paul G. Barash, Seventh Edition, Page № 583- 609
• 3.http://www.medscape.com/viewarticle/819629_2
• 4. Miller’s Anesthesia 8th edition.