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Undergraduate

Aims, Objectives and Responsibilities

This rotation provides an introduction to clinical anesthesia covering perioperative assessment and optimization, monitoring techniques, management of acute medical issues including resuscitation, acute pain management, application of basic sciences to clinical problems and provides exposure to, and experience with, technical skills such as basic and advanced airway management, intravenous catheter insertion, and possibly spinal anesthesia and arterial line insertion. (N.B.: Department policy stipulates that clerks are not allowed to attempt placement of central venous lines and epidural catheters). More specific objectives are included in the attached file.

Unlike much of clerkship, the anesthesia rotation allows clerks the opportunity to be one-on-one with an attending staff every day when feasible. Please use this opportunity to experience as much as possible by taking appropriate ownership of cases, reading ahead of time, and asking questions (there is no such thing as a silly question). The staff anesthesiologists don’t expect clerks to know a significant amount about the specialty, but will expect clerks to take initiative to learn and provide patient care. Staff are more than happy to let clerks attempt as much as possible, when appropriate, and will teach abundantly, but this will require the clerk to show interest, act professionally, prepare for the day by reviewing patients the day before, and read around cases. Not achieving these may exclude the clerk from being involved in the day’s activities.   

Please read the attached file for more information: Important_information_about_your_anesthesiology_revised_Jan_2020

 

Elective rotations of up to two weeks duration can be arranged for students who are interested in a more intensive introduction to anesthesia. These are very valuable if you are considering a residency in anesthesia.

Queen's students interested in an elective rotation should contact the departmental office 613-548-7827 or e-mail  Saulina Almeida, Undergraduate Assistant.

Students outside of Queen's should contact the deparental office 613-548-7827 or e-mail Saulina Almeida, Undergraduate Assistant.

The Department of Anesthesia is actively involved in the Queen's Student Observership Program.

This program allows students to observe a variety of medical specialties so students can make more informed career choices. Students are encouraged to visit the Operating Room and interact one to one with an anesthetist for a full day or half a day. During this time, they have the opportunity to discuss the role that an anesthetist plays in the provision of clinical care and the kinds of intellectual and psychomotor skills that are necessary to become an anesthetist. An attempt is made to provide an overview of the physiology, pathophysiology and pharmacology that anesthetists must know. As well, some of the equipment used and procedures performed by anesthetists are demonstrated.

Interested students should contact the departmental office 613-548-7827 or e-mail Saulina Almeida,  Undergraduate Assistant.

Please note:  We do not schedule observerships in the evenings, on weekends or on statutory holidays. 

The objectives of the preoperative visit are:

  1. Meet the patient
  1. Identify the present problem requiring surgery
  1. Identify any previous ongoing illnesses which may influence the anesthetic or surgery, in particular cardiac and respiratory diseases. Renal, hepatic, gastrointestinal, endocrine, neurological, and musculoskeletal conditions may also influence perioperative management
  1. Elicit any possible concerns about previous anesthetics or any family history of problems with anesthetics.
  1. Any adverse drug reaction and current medications.
  1. Examine the patient and in particular assess the airway
  1. Review any investigations and order others needed.
  1. Plan the anesthetic technique.
  1. Provide information for the patient and relatives about the anesthetic and postoperative care including pain management.
  1. Ask the patient to stop smoking.
  1. Ensure the patient is NPO for 6 hours for solids and 4 hours for clear fluids.
  1. Order any premedications required and all essential routine medications to be  
    given preoperatively.

  13. Ensure adequate postoperative care is available e.g. step down/ ICU.

Assessment of the airway

The incidence of difficult intubation is relatively low (~1:65) with a “failure to intubate” rate of ~ 1:2000. In an attempt to try and identify those patients who may fall into this category a variety of tests have been devised. Unfortunately no single test is ideal.

Causes of difficult intubation include:

1) Congenital:e.g. Pierre Robin syndrome.

2) Anatomical: Variants of normal e.g. prominent teeth, small receding chin, deep protruding mandible, short thick neck, pregnancy.

3) Acquired: e.g. scarring, swelling, malignancy, rheumatoid arthritis.

At the preoperative visit the anesthesiologist can perform a variety of tests to try and identify those who may be a difficult intubation. These include:

1.  The Mallampati Classification: this involves getting the patient to sit upright, open their mouth, stick out their tongue and say “Aaah”. The view of the posterior pharyx falls into four classes:

Class I - The soft palate, tonsillar fauces and uvula are visible.

Class II - The soft palate, tonsillar fauces and part of uvula visible. 

Class III - Only the soft palate is visible. 

Class IV - Only the hard palate is visible.

Class III and IV are associated with increasing difficulty to intubate.


2.  The Thyromental distance: a distance of less than 6.5cm or inability to admit three fingers associated with more difficult intubation.

The ability to prognath:

Class I: able to move bottom teeth in front of top teeth = normal

Class II: able to align bottom set to top set = some difficulty

Class III: bottom set stays behind top set = difficult to intubate

4. Neck mobility: ability to flex the lower cervical spine and extend the atlanto-occipital joint (sniffing the morning air position. This position results in axial alignment of the mouth, pharynx and larynx.

Laboratory Investigations

These tests vary depending on the patient but a few rules can be followed.

1. Complete blood counts should be performed on all patients who show signs of anemia or have an underlying condition which increases the risk of anemia (e.g. chronic illness, bleeding disorder, excess alcohol consumption, chemotherapy). It should also be done when large blood losses are likely during surgery.

It is routine in all women and men over 60yr.

2. Serum Electrolytes should be done on all patients over 40yr, those with renal disease, hypertension, diuretic therapy including bowel prep., diarrhoea or vomiting.

3. A Coagulation Screen if there is a history of bleeding disorder or on anticoagulation therapy.

4. An Electrocardiogram should be done on all patients over 40yr, any patient at increased risk of cardiac disease, have symptoms of cardiac disease, or show signs of

cardiac disease on physical examination.

5. A Chest x-ray is required in all patients with symptomatic pulmonary disease or underlying malignancy.

6. Urinalysis is required in all patients.

All other investigations are ordered if specific problems are identified on history and physical examination.

Premedication

These are given to provide amnesia, anxiolysis, antacid prophylaxis, analgesia, antisialogogue, autonomic control, allergy prophylaxis, and continuation of specific therapy.

Pre-existing illness:

Certain diseases are especially important during anesthesia. These include ischemicheart disease, congestive heart failure, hypertension, diabetes mellitus, reactive airways disease.

1) Ischemic heart disease (IHD)

Five percent of over 35yr olds have asymptomatic heart disease. IHD arises from a decrease in the supply:demand ratio for myocardial oxygenation. During anesthesia attempts are made to maximise oxygen supply and limit the oxygen demands of the heart.

Decreased oxygen supply:

O2 content – anemia?
hypoxia 
tachycardia 
increased preload 
hypotension 

Increased oxygen demand:
tachycardia 
increased preload 
increased afterload 
increased contractility

The time of highest risk of a perioperative myocardial ischemic event is not during surgery but around three days post operatively especially when opioid analgesics are used without supplemental oxygen therapy.

Patients with unstable angina, suboptimally controlled angina, or a myocardial infarction within the previous 6 months should not undergo elective surgery. Antianginal medication should continue right up to surgery and can be taken with a sip of water within an hour of surgery starting. This is especially true of b-blockers where there is a risk of rebound hypertension if suddenly withdrawn.

2) Congestive Heart Failure

Patients with impaired ventricular function and congestive heart failure do not tolerate anesthesia and surgery very well. Most anesthetic drugs are negative inotropes and so decrease the strength of contraction of an already weak muscle. Also the stress of surgery and fluid shifts that can occur during an operation increases the demands on a poorly functioning myocardium. No patient should undergo anesthesia in uncontrolled congestive heart failure.

Hence it is important to recognise these patients preoperatively so their condition can be optimised.

Symptoms include: orthopnoea, PND, ankle swelling, poor exercise tolerance.

Signs include: raised JVP, pitting odema of legs, tachycardia, basal crackles, S3 or S4 on auscultation.

3) Hypertension

Poorly controlled hypertension increases the anesthetic risk. It results in overactive cardiovascular responses, poor left ventricular relaxation, cerebrovascular events, myocardial ischemia and infarction, and renal failure. Many patients are hypertensive when first admitted to hospital due to anxiety, so before hypertension is diagnosed a series of elevated readings are needed whilst the patient is as relaxed as possible.

It is important that antihypertensive medication is continued up until surgery to prevent the possibility of rebound hypertension.

4) Reactive Airways Disease

Anesthesia can precipitate life threatening bronchospasm in patients with reactive airways disease (e.g. asthmatics and COPD patients). This can be due to anxiety, anesthetic drugs, and airway manipulation. Anesthetics also worsen mucus trapping by drying secretions and impairing cilial function. These patients should have their airways disease under optimal control prior to elective surgery and should continue their inhalers and steroids up until the day of surgery. Any patient who has been on steroids in the previous 6 months will need steroid replacement to cover the stress of surgery since there may still be a degree of adrenal suppression. If possible these patients should be done under regional technique (spinal, epidural, peripheral block) to avoid airway manipulation. Unfortunately this is not always possible. Hence patients with pulmonary disease need to have their treatment optimised and surgery postponed if there is any suspicion of infection. Treatment options include stopping smoking, bronchodilator therapy, physiotherapy to mobilise secretions, and antibiotics where appropriate.

5) Diabetes Mellitus

The first thing to assess in this group of patients is their diabetic control. All except life saving emergency surgery is delayed until hyperglycemia, dehydration and acidosis are controlled. This control is aimed at preventing perioperative hypoglycemia / hyperglycemia. Hyperglycemia can result in delayed wound healing and increased risk of infection but hypoglycemia can result in irreversible neuronal damage. The risk of hypoglycemia is increased in those patients on long acting oral hypoglycemic agents or long acting insulin. The stress of surgery causes a reduction in the body's response to hypoglycemia (glucagon, epinephrine) and b-blockade can mask the signs of hypoglycemia. Equally there is a need to prevent hyperglycemia intraoperatively.

The inhalational agents increase the blood sugar levels and the stress of surgery causes a degree of insulin resistance.

The aim intraoperatively is to maintain control of blood sugar levels in the high normal range rather than run the risk of a period of hypoglycemia by aggressive control.

Patients on oral hypoglycemic agents should have these held the morning of surgery and a solution containing 5% dextrose started. This should continue through surgery with regular monitoring of blood sugars perioperatively. Those taking insulin can be managed with an insulin and dextrose infusion started prior to surgery. Alternatively they can take half their intermediate acting insulin the morning of surgery and a solution of dextrose given throughout the perioperative period. Whichever method is used the aim is to monitor blood sugar levels and alter management accordingly.

These patients have a multisystem disease and the complications should be looked for. These include vascular disease, hypertension, cardiomyopathy, nephropathy,neuropathy, retinopathy, risk of infection, decrease in respiratory function.

Look for associated conditions e.g. thyroid disease, parathyroid disease, obesity, and pregnancy.

 

Online Modules

You will be required to complete four online modules. These can be completed when clinical duties allow during some days or can be done at home. Material from these modules will appear on the final multiple choice examination. 

Modules
  1. Post-partum Hemorrhage
  2. Preoperative Assessment
  3. Intraoperative Management
  4. Cardiac Physiology