santosh k dhungana

MD GP JR II

pre-op assessment

pre-anesthetic prescribing

induction agents

muscle relaxants

reversal

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goals

reduce patient risk

reduce morbidity of surgery

promote efficiency

reduce costs

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anesthesiologist shall be responsible for

determining the medical status of the patient

developing a plan of anesthesia care

acquainting the patient with the proposed plan

ASA

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study evaluating methods of reducing preoperative anxiety thorough preoperative evaluation can be as effective as

an anxiolytic premedication

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Review available medical records

Interview and perform focused examination of the patient Discuss medical hx, including previous anesthetic experiences and

medical therapy

Assess those aspects of the patient’s physical condition that might affect decisions regarding perioperative risk and management.

Order/ review pertinent available tests and consultations as necessary for the delivery of anesthesia care

Order appropriate preoperative medications

Ensure that consent has been obtained for the anesthesia care- BRAN (benefit, risks, alternatives, if Not done then..)

Document in the chart that the above has been performed

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Current Problem- History of present illness

The proposed surgery – affects type of anaesthesia/ position

Other known problems- Any comorbidities (DM, HTN, psychiatric illness)

Drug history- Present therapy (prescription/ over-the-counter), alcohol, tobacco

Allergy history- drugs, food, latex, etc.

Anesthetic history- Previous anesthetics, operations, complications, h/o malignant hyperthermia (“allergy to anesthesia”)

System review- Screening of any undiagnosed systemic illnesses

Miscellaneous- Last oral intake (ER) 7/15/2014 7

General appearance- Comfortable, in distress, sick looking, physique, wt, ht, BMI

Vital signs- Temp, pulse, BP, RR

Head to toe examination- Pallor, icterus, clubbing, cyanosis, edema, dehydration, peripheral veins,

pre-existing iv cannulae

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dentition- loose or chipped teeth, caps, bridges, or dentures poor anesthesia mask fit expected in edentulous patients and

significant facial abnormalities

prominent upper incisors, large tongue, short neck suggest difficulty may be encountered during tracheal intubation

nostrils

thyromental distance: 5cms

Sternomental distance: 12.5 cms

mandibular protrusion test

flexon and Extension of the neck

Cervical spine- Important in trauma, RA, cervical spondylosis

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A screening evaluation regarding history of tobacco use, shortness of breath, cough, wheezing, stridor, snoring or sleep apnea

recent history of an upper respiratory tract infection

Patient's ability to carry on a conversation or to walk without dyspnea

Physical exam- assess the respiratory rate as well as the chest excursion, use of accessory muscles

Auscultation to detect decreased breath sounds, wheezing, stridor

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Site of surgery thoracic, aortic or upper abdominal surgery has highest risk

Type of surgery abdominal aortic aneurysm repair, thoracic, upper abdominal have

highest risks followed by neck, peripheral vascular, and neurosurgery

Neurosurgery and neck surgery associated with perioperative aspiration pneumonia

Laparoscopic surgery have lesser risk than open surgery

Duration of surgery longer the duration, longer the time exposure to anesthesia

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tobacco/ smoking increase carboxy-hemoglobin

decrease ciliary function

increase sputum production

stimulates cardiovascular system secondary to nicotine

asthma/COPD increased airway responsiveness

drugs may have adverse reactions with anesthetics

chronic CO2 retention in COPD

obstructive sleep apnea susceptible to the respiratory depressant and airway effects of

sedatives, narcotics, and inhaled anesthetics

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General appearance including weight, BMI

Vital signs Pulse and its characteristics( rate, rhythm, character, volume, delay,

all peripheral pulses)

BP (if needed in both arms)

Temperature, RR

Head to toe examination JVP, anemia, cyanosis, clubbing, edema

Precordial examination Inspection/Palpation- apical impulse, heave, thrills

Auscultation- heart sounds, murmurs

Auscultation of basal lung fields

Assessment of liver size and position

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Age associated with multisystem disease,

Previous MI 5-8% risk of periop reinfarction Mortality rate of reinfarction 36-70% Risk of reinfarction decreases with time

30% <3 mnths 6% >6mnths

CHF symptomatic CHF- predictor of perioperative pulmonary

edema

Hypertension Leading cause of concern Not a significant risk factor alone (esp. if <180/110), but due

its end-organ damage like LVF, renal failure and stroke 7/15/2014 15

DM risk of CAD, silent MI, renal insufficiency

Equal risk as nondiabetics with previous MI

VHD AS- 14 fold greater risk as compared with those without AS

risk of IE

Arrhythmias Frequent PVCs and nonsinus rhythms

CHB, LBBB, 2 heart block (Mobitz type II)

Others Smoking, hyperlipidemia, renal failure, anemia, depression,

hypoalbuminemia

Inflammatory markers: CRP, b-type natriuretic peptide7/15/2014 16

Renal disease- important implications for fluid management and metabolism of drugs.

Liver disease -associated with altered protein binding, volume of distribution of drugs, coagulation abnormalities

Musculoskeletal System- anatomy evaluated for procedures such as a nerve block, regional anesthesia, invasive monitoring

Neurological- history of prior stroke -increased risk for a perioperative stroke

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CBC

Ur. / Cr.

Na/ K

PT/ INR

CXR

ECG

Urine RE/ME

Other case pertinent inv.

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MET, metabolic equivalent of the task. 1 MET = consumption of 3.5 mL O2/min/kg of body weight.

Patients with MET less than 4 or 5 have higher risk of perioperative cardiac morbidity

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NYHA: New york Heart AssociationCCVSA: Canadian Cardiovascular Society

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administration of drugs prior to anesthesia to allay apprehension

produce sedation

facilitate the administration of anesthesia to the patient

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Devoid of any side effects

Minimal depression of respiration andcardiovascular function.

Simple and pleasant to take.

Should act over reasonable period of time.

Should be effective in all patients.

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Relief of anxiety

Sedation

Amnesia

Analgesia

Drying of airway secretions

Prevention of autonomic

reflex responses

Reduction of gastric fluid volume and increased pH

Antiemetic effects

Reduction of anesthetic requirements

Facilitation of smooth induction of anesthesia

Prophylaxis against allergic reactions

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anxiolytics Children- syr promethazine (6.25 mg/ml)

5- 10 ml hs/ cm

Young adults- diazepam 5-10 mg hs/ cm

Elderly –lorazepam 1- 2mg hs/ cm

Antiemetics

Antacids/ ppi

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Hypertension Antihypertensive drugs to be continued except Losartan &

Diuretics

• RHD• Prophylactic antibiotics should be considered

• Patients on anticoagulant therapy- warfarin should be substituted by heparin 3-5 days prior to surgery

• IHD-• Anticholinergic mainly atropine to be avoided.

• Aspirin to be discontinued 7 days before surgery

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• Bronchodilators, steroids should be continued

• Prophylactic antibiotics in COPD patients

• Inhaled β2-agonists, cromolyn, or steroids should be continued up to the time of surgery

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Objectives

• avoid hypoglycemia, excessive hyperglycemia, ketoacidosis

• metformin should be held if there is decreased renal function- risk for the fear of Lactic acidosis.

• glimepiride (Sulfonylureas) should be held while the pt. is NPO

• Thiazolidinedione can be continued as they do not predispose to hypoglycemia

• α-glucosidase inhibitor should be held

• Premedication to avoid aspiration, N/V

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Well-controlled type 2 diabetics do not require insulin for minor surgery.

Poorly controlled type 2 diabetics and all type 1 diabetics having minor surgery and all diabetics having major surgery need insulin.

For major surgery, serum glucose > 270 mg/dL, the surgery should be delayed while rapid control is achieved with intravenous insulin.

If the serum glucose >400 mg/dL, surgery should be postponed and the metabolic state restabilized.

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Administer 1/2 to 2/3rd of the patient's usual intermediate-acting insulin subcutaneously on the morning of surgery

In addition to this basal insulin, a regular insulin sliding scale (RISS) can be added and titrated to blood glucose measurement.

Alternatively, an insulin infusion of 1 to 2 U/hr (100 U regular insulin in 100 mL normal saline at 1 to 2 mL/hr) can meet basal metabolic needs and be adjusted to maintain blood glucose at the desired level.

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With either method, a slow glucose infusion (dextrose 5% in water at 75 to 100 mL/hr) will prevent hypoglycemia while the patient is fasting.

Some authorities recommend a combination glucose-insulin or glucose-insulin-potassium infusions (GIK)

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Management of Diabetes Mellitus in Surgical Patientshttp://spectrum.diabetesjournals.org/content/15/1/44.full

Intraoperative GIK solution given to diabetic patients with CABG operation provides more stable CI, shorter time of MV, more stable values of potassium which provides normal rhythm and less AF onset, less insulin to maintain target glycemia. All the above mentioned provides more stable intraoperative hemodynamic and better recovery of diabetic

Glucose-Insulin-Potassium (GIK) solution used with diabetic patients provides better recovery after coronary bypass operations.

Straus S, Gerc V, Kacila M, Faruk C.

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“Sliding scale insulin” is not recommended for the management of hyperglycemia.

“set and forget”

Basal + pre-meal better

https://www.diabetessociety.com.au/documents/PerioperativeDiabetesManagementGuidelinesFINALCleanJuly2012.pdf

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Type II patients taking oral agents alone, RISS can be added to control blood glucose levels.

Patients receiving chronic insulin can be treated similarly to the type I patient by giving 1/2 the usual NPH insulin dose the morning of surgery, supplemented by a RISS, or an insulin infusion titrated to blood glucose.

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Clear liquids- 2hr

Breast milk- 4 hr

Light snacks/ cerelac - 6 hr

Full meal- 8 hr

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state of drug induced reversible unconsciousness and loss of protective reflexes

consist of hypnosis, amnesia, analgesia, relaxation of skeletal muscles, and loss of autonomic reflexes

Balanced anesthesia=

hypnotic+ amnesic + analgesics + muscle relaxant

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Components of GA Pre-anesthetic check up (PAC)

Premedication

Induction

Maintenance

Recovery

Postoperative Care

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Advantages fast onset of anesthesia than inhalation, (10-20 seconds)

induce total unconsciousness

avoidance of the excitatory phase of anesthesia (Stage II)

complications related to induction of anesthesia.

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Propofol (10 mg/ml)-

<55 yr – 2- 2.5mg/ kg slow iv

>55 yr- 1-1.5 mg/kg slow iv

Onset 30- 45 s

Duration- 20-75 min

Metabolism- hepatic conjugation

Excretion- urine

s/e- injection site burning, hypotension, apnea, rash pruritus, cardiac s/e

Most commonly used

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Ketamine (10mg/ml) 1-4.5 mg/kg slow iv once

1-2 mg/ kg infusion @ 0.5mg/kg/min

Produces dissociative anesthesia

Blocks NMDA receptors

Onset- 30 s

Duration- 5 -10 mins

Metabolised by liver

Excreted in urine

s/e- emergence reaction, htn, raised ICP, tachycardia, hallucinations

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Sodium thiopental ultra-short-acting barbiturate 4–6 mg/kg Largely replaced by propofol mainly metabolized to pentobarbital s/e- hypotension, apnea and airway obstruction caution with liver disease, severe heart disease,

severe hypotension, a severe breathing disorder, or a family history of porphyria

Etomidate (2mg/ml) 0.3-.6 mg/ kg iv over a minute Onset 60s; duration- 3-5 mins Hepatic metabolism, excreted in urine s/e- adrenal suppression, pain, apnea, arrythmias Less often used

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Advantages: Excellent analgesia

Minimal hemodynamic depression

Good suppression of endotracheal tube response

Problems: Respiratory depression

Incomplete suppression of intraoperative awareness

Used mainly for cardiac anesthesia and also in smaller doses as a part of balanced anesthesia for non-cardiac cases

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Fentanyl More lipid soluble than morphine

Rapid onset (60 sec)

Elimination half time (200 min) is longer than the duration of clinical effect

Very highly bound to lung as a function of time. So half-life of effect depends upon duration of administration because of an increase in storage.

Available as IV, transdermal patch & lollipop

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Isoflurane 1- 3% Rapid onset, short acting MAC 1.3% s/e N/V, hypotension, arrythmias

Sevoflurane 1.4- 2.6% Onset 2-3 min expensive s/e hypotension, respiratory irritation, seizures

Halothane potent anesthetic MAC 0.74 20% metabolized in liver s/e- liver injury 1in 10,000 Less preferred

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Difficult IV access

Anticipated difficult airway

Children

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used for facilitate intubation of the trachea facilitate mechanical ventilation optimize surgical working conditions

Depolarizing muscle relaxant

Succinylcholine Nondepolarizing muscle relaxants

Short acting Intermediate acting Long acting

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Succinylcholine Most often used to facilitate intubation

dose- 1-1.5 mg/kg

Onset 30-60 seconds

duration 5-10 minutes

s/e- Cardiovascular, Fasciculation Muscle pain,

Increase IOP, Increase ICP, intragastricpressure

Malignant hyperthermia

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Nondepolarizing Muscle Relaxants Do not depolarized the motor endplate

Act as competitive antagonist Excessive concentration causing channel blockade

Act at presynaptic sites, prevent movement of Ach to release sites

Long acting Pancuronium

Intermediate acting Atracurium, Vecuronium, Rocuronium, Cisatracurium

Short acting Mivacurium

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Vecuronium Analogue of pancuronium

much less vagolytic effect and shorter duration than pancuronium

Onset 3-5 minutes

duration 20-35 minutes

Intubating dose 0.08-0.12 mg/kg

Elimination 40% by kidney, 60% by liver

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Neostigmine 0.03-0.07 mg/kg iv

Max dose 5mg

10-20 mins

Competitive inhibitor of choliesterase

Reverses action of muscle relaxants

Administered with anticholinergics

Atropine (

Glycopyrrolate (0.2 mg per 1 mg of neostigmine)

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Miller’s Anaesthesia- 7th Edition

Clinical Anaesthesia – Paul G. Barash, 6th Edition

ACC/AHA guidelines on perioperative cardiovascular assessment

Uptodate 21.2

Medscape

www.asahq.org

http://spectrum.diabetesjournals.org/content/15/1/44.full

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Thank you!!

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