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Q: What is anesthesia?
Q: What is an anesthesiologist?
Q: What is a nurse anesthetist?
Q: How is anesthesia practiced in the North America, Asia, Europe, Latin America, Africa?
Q: What drugs are used to administer an anesthetic?
Q: What are the complications of anesthesia?
Q: What about postoperative pain relief?
Q: What does an anesthesiologist do?
Q: What is the difference between an anesthesiologist and a nurse anesthetist?
Q: What is General Anesthesia?
Q: What is spinal and epidural anesthesia?
Q: How does my anesthesiologist know everything is OK during my surgery?
Q: I have a "bad heart" - should I worry?
Q: I am a smoker - is this a problem?
Q: Could I be allergic to the anesthetic?
Q: Do I really need an IV?
Q: When can the IV come out?
Q: I have a loose tooth - is that a problem?
Q: What happens when I "go to sleep"(general anesthesia)?
Q: Could I wake up during the surgery?
Q: How will my pain be treated after the surgery?
Q: If I'm given morphine after the anesthetic will I get addicted?
Q: Will I have a sore throat after the surgery?
Q: Will I experience nausea and vomiting after the surgery?
Q: Will I receive blood during my surgery?
Q: A relative of mine had a bad reaction to anesthesia. Could it happen to me?

Pediatric Anesthesia

Q: How is cardiac output different between an infant and an adult, and what are the anesthetic implications of these differences.
Q: For a 900 gm premature infant, how would you specifically treat the following intraoperative events?
    1. Increased HR, Increased BP
    2. Increased HR, Decreased BP
    3. Decreased HR, Decreased BP
Q: What are normal vital signs for a newborn, 6 month old, 1 year old, and 6 year old?
Q: Why are children predisposed to intra-operative bradycardia, and what is the treatment (mg/kg)?
Q: Is there an absolute minimum dose for atropine? If so, what is it and why?
Q: Why are children predisposed to hypothermia? What are the effects of volatile anesthetics on nonshivering (brown fat) thermogenesis?
Q: What is the dose/kg of the following drugs:
    1. Ondansetron
    2. Metoclopramide
    3. Ketorolac
    4. Atropine
    5. Neostigmine
    6. Cefazolin
    7. Ampicillin
    8. Dexamethasone
    9. Naloxone

Q: What is the formula for calculating ETT size?
Q: What laryngoscope blade type(s) and size(s) is/are appropriate for:
    1. Newborns
    2. 1-6 months
    3. 6 months-6 years
    4. 6 years-10 years
Q: At what age do you use a cuffed ETT, and why?
Q: What is your detailed algorithm for treating laryngospasm?
Q: How are the physical characteristics of a child's airway different from an adult's?
Q: Why does a child desaturate quickly during induction of general anesthesia?
Q: Why is prevention of air bubbles in the IV especially important in children?
Q: Explain why some anesthesiologists will NOT use succinylcholine in children, and others WILL use it.
Q: What patient population is at risk for MH? List examples of disorders and operations associated with MH. What is the phone number for MHAUS?
Q: What is the treatment of MH in detail? What is masseter spasm, and what would you do if you saw it during induction of a child?
Q: What are NPO guidelines for a child? Differentiate between formula, breast milk, and clear liquids.
Q: Describe the anesthetic implications of the following syndromes:
    1. Osteogenesis Imperfecta
    2. Cerebral Palsy
    3. Pierre Robin Syndrome
Q: What are the appropriate LMA sizes for a child? List by weight and/or age.
Q: What are the different types of tracheo-esophageal fistula, and what are the airway management implications? Any other anesthetic implications?
Q: What birth history questions should be asked in a preop interview for a neonate?
Q: A 1 month old, ex-35 week premie is brought for elective outpatient surgery. Do you let the baby go home postoperatively, or observe him for 24 hours? Why?
Q: What is your choice of anesthetic induction technique for a child with severe asthma?
Q: Which intravenous agents (including induction agents, paralytics, opiates, etc) are associated with histamine release?
Q: What is your airway management plan for a child with:
    1. Choanal atresia
    2. Cleft lip and palate
    3. Micrognathia
Q: What is the formula for estimating weight of a child if all you know is the age?
Q: What are the anesthetic implications of pyloric stenosis?
Q: What is the significance of a past history of a viral upper respiratory infection within the past 2-4 weeks? Would you cancel an elective case if a child had a history of infection 1 week ago, but seems fine now? Is there a difference in these children between LMA placement and intubation?
Q: What is the oxygen consumption in ml/kg/min of a child vs. an adult? What are the anesthetic implications?
Q: What is the hemoglobin in ml/kg of a neonate, a 6 month old, and a 6 year old?
Q: How are the oxygen-hemoglobin curve and oxygen affinity affected by fetal hemoglobin?
Q: What are the anesthetic implications?
Q: Would you use 100% oxygen on a 1 month old baby having an elective procedure? Why or why not? What if the child were 6 months old?
Q: What is your maintenance fluid of choice for neonates?
Q: On what part of the body would a branchial cleft cyst excision take place? What are the anesthetic implications of this surgery?
Q: What are the differences between an omphalocele and gastroschesis?
Q: A nervous, crying mother of a calm 2 year old asks if she can come back for induction of anesthesia. How do you respond, in detail?
Q: A mother tells you that her 6 yo child is a Jehovahâ€Â™s Witness, and that she wants him to receive no blood products no matter what. His Hgb is 7, and he is having an extensive bowel resection. In detail, how do you respond?
Q: Describe in detail how you would perform a caudal block on a 6kg infant having hypospadias repair, including medications and doses.
Q: Describe in detail how you would intubate a child with severe epiglottitis. 3 days later, you are again consulted to extubate the child. Describe your plan.
Q: A 5yo has just undergone exploratory laparotomy. What are your postoperative pain orders, and would you write for a PCA? If so, how would you dose it?
Q: What are the anesthetic implications for a neonate with a large diaphragmatic hernia? How would you plan your anesthetic?
Q: In detail, what is ECMO?
Q: What are the advantages and disadvantages of preoperative midazolam for tonsillectomy in children? What is the dose?
Q: Describe the differences between halothane and sevoflurane for children. Specifically comment on potency, pungency, MAC, side effects, and induction/emergence characteristics.
Q: Describe the renal and hepatic function of a neonate. What are the anesthetic implications? When do they normalize?
Q: At what age is MAC requirement highest? Draw the age vs. MAC curve.
Q: What are the anesthetic implications of a child with Downs Syndrome?
Q: What are the anesthetic implications of a child with Cystic Fibrosis?
Q: Are there different kinds of anesthesia?
Q: What are the risks of anesthesia?
Q: What about eating or drinking before my anesthesia?
Q: Should I take my usual medicines?
Q: Could herbal medicines and other dietary supplements affect my anesthesia if I need surgery?
Q: What makes office-based anesthesia different?
Q: How is the epidural block performed for labor and delivery?
Q: Should I stop smoking before my surgery?
Q: Is there anything the anesthesiologist can do to prevent urinary retention?
Q: Are anesthetic risks increased with long surgeries?
Q: Are spinal anesthetics safe?
Q: Should all of my muscles be sore for a day and a half after breast surgery?
Q: I'm having problems swallowing and speaking long after surgery. What advice do you offer to help improve my problems?
Q: Should my throat be sore five weeks after surgery?
Q: Should my IV site continue to be sore and swollen three weeks after surgery?
Q: How risky is anesthesia?
Q: Why can't I eat and drink before anesthesia?
Q: What kind of anesthesia will I have?
Q: What is a general anesthetic? What are the side effects and possible complications?
Q: What is a spinal anesthetic? What are the side effects and possible complications?
Q: What is an epidural anesthetic? What are the side effects and possible complications?
Q: What is a local anesthetic? What are the side effects and possible complications?
Q: Can I get a preoperative sedative before I go to surgery?
Pain Relief in Labor and Delivery

Q: What are my possible options for pain relief during labor and delivery?
Q: Who performs spinal and epidural anesthesia?
Q: What is an epidural anesthetic?
Q: How is an epidural catheter placed?
Q: What kind of pain relief can I expect from an epidural anesthetic?
Q: Will an epidural slow my labor?
Q: Will an epidural increase my chances of needing a C-section?
Q: What is a spinal anesthetic?
Q: What are the most common side-effects of epidural and spinal anesthesia?
Q: What are the possible complications of epidural and spinal anesthesia? Q: What is the medical history of Anesthesia?
Q: Why does the anesthesiologist need my medical history?
Q: Why are patients not allowed to eat or drink before surgery?
Q: What are local, regional and general anesthetics?
Q: Who will give the anesthetic?
Q: What type of monitoring will be used?
Q: What emergency preparations and procedures will be in place?
Q: With respect to post-operative pain, who gives the prescription? Who do you call with pain problems?
Q: What are the major types of anesthesia?
Q: What kinds of medicines are used for anesthesia?
Q: What are the potential risks or complications of anesthetic medicines?
Q: What medical conditions may increase my risk of complications during anesthesia?

Preparing for anesthesia:

Q: How do I prepare for anesthesia?
Q: Do I need to fast before my procedure?
Q: How can I reduce anxiety before my procedure?

Q: What happens during anesthesia:

Q: What happens while I am being given anesthesia?
Q: How long will it take for me to recover from anesthesia?
Q: Are there any side effects after anesthesia?
Q: What are the risks of anesthesia?
Q: What are some side effects of anesthesia?
Q: Why do I need to fast the night before surgery?
Q: What if I get a cold, fever or cough before surgery?
Q: What should I do if I have a pacemaker?
Q: Should I take my regular medications?
Q: What are options for blood transfusions?
Q: Where will I go after surgery?
Q: Can I have visitors in the recovery room?
Q: What are my options for pain control after surgery?
Q: Is there anything else that anesthesiologists do?
Q: What are the pre-surgical appointments for? Why are there so many questions?
Q: What do I need to tell the anesthesiologist?
Q: What kind of anesthesia will I have?
Q: What does the anesthesiologist do during the surgery?
Q: Will I need to receive blood for the surgery?
Q: Can you give me more information about general anesthesia?
Q: Do I have to have a breathing tube?
Q: What is regional anesthesia?
Q: Can I request the specific type of anesthesia that I want?
Q: What are the common risks of anesthesia?



General Anesthesia

Q: What is transpulmonary pressure? How about FRC and VC?
Q: Can you draw the lung capacities/volumes diagram? What is normal FRC and VC in cc/kg?
Q: What happens to FRC with GA? Why is low FRC bad? What conditions lower FRC?
Q: What part of the lung is usually ventilated best, the apex or the base? What happens with GA?
Q: What is the alveolar gas equation?
Q: What are the formulas for calculating oxygen content/delivery/consumption?
Q: What is the formula for calculating shunt fraction?
Q: What is the difference between shunt and V/Q mismatch? Is hypoxemia from a PE due to shunt or dead space?
Q: How would you assess a Patient's COPD? How do you assess its severity?
Q) Are preoperative PFTs required for COPD patients?
Q: What risk factor predispose to postop pulmonary dysfunction?
Q: How does the presence of COPD affect your choice of anesthetics?
Q: How would you ventilate a patient with COPD?
Q: How would the presence of a difficult airway affect your induction in a Pt with asthma?
Q: Would you use ketamine? Why or why not?
Q: Is deep extubation indicated for a Pt with a history of severe brochospasm?
Q: How can COPD be distinguished from restrictive lung disease by spirometry?
Q: What type of infiltrative disorders cause restrictive lung disease? Draw the flow/volume loops for each disorder.
Q: What are the different causes of pulmonary edema?
Q: How can you distinguish between cardiogenic and noncardiogenic pulmonary edema?
Q: A Pt develops stridor after extubation, and then desaturates after reintubation.
Q: What is your differential diagnosis and treatment plan?

Q: How would you induce anesthesia for a Pt with a large anterior mediastinal mass causing significant tracheal compression?
Q: A 57 year old male who had an MI seven months ago is scheduled for cataract Sx. Do you need an extensive (or any) cardiac workup?
Q: After a retrobulbar block, a Pt become unresponsive, what is your differential diagnosis and response?
Q: A Pt complains of postop eye pain following a prone operation. What is your differential diagnosis? What if he complains of blindness? What are the risk factors, if any?
Q: What would you tell a Pt if a corneal abrasion occurred? How do you treat it acutely?
Q: What is the significance of cervical involvement with rheumatoid arthritis?
Q: Is regional anesthesia a good or bad idea in a patient with a difficult airway?
Q: During insertion of an artificial prosthesis in an orthopedics case, the Pt becomes hypotensive, what is your differential diagnosis, and what would you do?
Q: Thirty minutes after inflation of a tourniquet during an orthopedics case, the Pt develops unexplained HTN. What is your differential diagnosis and management?
Q: Is postop pulmonary function and outcome definitely improved with regional versus general anesthesia?
Q: What is your plan for perioperative pain control for a total knee or total hip replacement?
Q: How is electrical shock in the OR quantitatively classified?
Q: What safety measures are available to reduce the chances of electric shock in the OR?
Q: What is an isolation transformer and how does it work?
Q: The line isolation monitor alarms during a code situation when the defibrillator is plugged in for emergency cardioversion. What do you do?
Q: What features on the anesthetic machine prevent the delivery of a hypoxic mixture?
Q: How much N2O is left in a cylinder if it reads 745 PSIG?
Q: What is a fail-safe device on an anesthetic machine?
Q: What is the problem with repeated use of the O2 flush valve?
Q: How does use of a vaporizer at higher altitude affect output? Are there differences between agents/vaporizers?
Q: Are there any toxic substances produced in CO2 canisters? How does the choice of Baralyme or soda lime affect production? Is Baralyme still available? Are there differences between volatile agents and substance production?
Q: How do you check the low pressure system on an anesthesia machine?
Q: The PEEP reads 15 cm H2O when none was intended, what would you do?
Q: A postop Pt is oliguric and this is blamed on fluoride nephrotoxicity because isoflurance was used. What is your response? Any difference if they blamed it on Sevoflurane?
Q: Should you avoid succinylcholine in a patient with dialysis-dependent renal failure? What potassium level is your cut-off for succinylcholine?
Q: Can you safely reverse neuromuscular blockade in a patient with renal or hepatic failure?
Q: Who is at risk for acute renal failure? What is the FeNa? How do you differentiate between pre-renal, renal, and post-renal drop in urine output?
Q: What is TURP syndrome? What is the best anesthetic technique for TURP and why? How would you diagnose and treat a suspected case? What is central pontine myelinolysis?
Q: How can you preserve hepatic blood flow intraop? What factors determine hepatic blood flow? What blood pressure considerations should you have when anesthetizing a patient for liver resection?
Q: What LFTs, if any, would you order for a Pt undergoing a laparoscopic cholecystectomy? What would you say if a patientâ€Â™s postoperative LFT elevation were blamed on the volatile anesthetic?
Q: What are your concerns in a Pt with chronic alcoholism? How would you manage the anesthetic for a drunk trauma patient that was a chronic drinker versus one that was not?
Q: How would you manage the airway of a drunk and combative patient with a suspected C-spine injury and oral trauma?
Q: Is a rapid sequence induction a good idea for severe liver cirrhosis Pt? Why? Which agents would you avoid, if any? What preop labs/tests would you order in a liver cirrhosis Pt? Is gastroparesis a risk in patients with end-stage liver and/or renal disease?
Q: What tests for coagulation are normally available? What are D-dimers?
Q: Should all Pts with VWD receive DDAVP preop? How long does it take DDAVP to work? How long does it take vitamin K to work? How much FFP would you need to give someone with a coumadin-induced coagulopathy? Letâ€Â™s say their INR was 1.9.
Q: After 10 units of emergency type O PRBCs, would you administer type-specific blood if it becomes available? Why or why not? How about after 4 units? How about FFP?
Q: How would you decide whether the Pt with sickle cell anemia requires transfusion preop? What are your goals for the transfusion?
Q: What is the Purpose of the Preoperative Anesthesiology Clinic?
Q: How Do I Contact the Preop Clinic?
Q: What is the Purpose of Preoperative Assessment?
Q: What are the Surgery or Primary Care Clinics' Responsibilities?
Q: Why do Surgeries get Postponed?
Q: What is a "Current" Work-up?
Q: Which Patients are Usually Poor Candidates for Outpatient Surgery?
Q: Why do Surgeries get Postponed?
Q: What is a "Current" Work-up?
Q: Which Patients are Usually Poor Candidates for Outpatient Surgery?
Q: Who should monitor sedation?
Q: What are the side effects of sedation?
Q: What should patient expect immediately following the procedure?
Q: What is the role of the caregiver after the anesthesia?
Q: What is intravenous sedation?
Q: What is conscious sedation?
Q: Are there other levels of sedation?
Q: List 3 symptoms of poor ventricular function (history).
Q: List 3 signs of poor ventricular function (physical).
Q: What information can be derived from exercise electrocardiography?
Q: What information can be derived from echocardiography?
Q: What information can be derived from cardiac catheterization?
Q: List 5 conditions that are detrimental to myocardial oxygen balance in patients with coronary artery disease.
Q: What are the branches of the right and left coronary arteries?
Q: What is the blood supply of the AV node?
Q: What is the blood supply of the SA node?
Q: List 3 manifestations of myocardial ischemia in a patient under general anesthesia.
Q: What are the determinants of blood pressure?
Q: What are the determinants of cardiac output?
Q: What are the determinants of oxygen content?
Q: What are the determinants of oxygen delivery?
Q: What are the determinants of oxygen consumption?
Q: What coronary artery and territory of the heart is monitored by leads II, III and AVF?
Q: What coronary artery and territory of the heart is monitored by leads V4 and V5?
Q: What coronary artery and territory of the heart is monitored by lead I and AVL?
Q: List 3 important considerations for anesthesia in patients with mitral stenosis.
Q: List 3 important considerations for anesthesia in patients aortic stenosis.
Q: List 3 advantages of using opioids such as fentanyl for cardiac anesthesia.
Q: List 3 disadvantages of using opioids such as fentanyl for cardiac anesthesia.
Q: What is the mechanism of action of nitroglycerin in patients with myocardial ischemia?
Q: What are the main indications for inserting a pulmonary artery catheter (PAC)?
Q: What parameters can be measured and calculated from a pulmonary artery catheter?
Q: Describe the anatomical location of the internal jugular vein.
Q: What is the mechanism of action of heparin?
Q: What is the mechanism of action of protamine?
Q: List 3 side effects of protamine.
Q: What does the ACT measure?
Q: What does the PT measure?
Q: What does the PTT measure?
Q: List 5 essential components of the cardiopulmonary bypass circuit.
Q: List 5 essential tasks to perform before and immediately after initiating bypass.
Q: List 5 causes of hypotension during initiation of bypass.
Q: What is the significance of cardiopulmonary bypass time.
Q: What is significance of

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GENERAL ANESTHESIA

Sub-topics
Induction (“going off to sleep”)
Intravenous induction
Inhalation (gas) induction
Not just a recipe !
Breathing during anesthesia
Muscle relaxation
Airways and breathing tubes
Awake intubation
Induction of anesthesia in children
Your role as a parent during induction of anesthesia
Emergency induction of general anesthesia
Maintenance of anesthesia (“keeping you asleep”)
Emergence (“waking up”)

induction (“going off to sleep”)

our anesthesiologist may start your anesthesia or induce ‘sleep’ in one of three ways. Induction may be:

• intravenous (into the vein): the most common method

• inhalation (by breathing in) sometimes called “gas induction”: often used in children

• intramuscular (into the muscle) injection: now used very rarely.

Intravenous induction

Before having an intravenous induction, you may have had local anesthesia cream applied to the skin over the vein to be used for the initial injection. The location of the vein depends on the anesthesiologist’s preference, the site of the operation, and the appearance of your veins. Often the veins on the back of the hand or forearm are used. The choice of hand depends on whether you are left- or right-handed, because having a bruise on the back of your dominant hand may cause discomfort afterwards. Also, if your intravenous line must remain in place for some time, you will find it easier to be able to do things, such as combing your hair or brushing your teeth, if your intravenous is not in the hand with which you normally do these things.

Having wiped away the cream and applied some cleaning alcohol to the skin, your anesthesiologist inserts a cannula or fine plastic tube into the vein. This is accompanied by a sensation varying between slight pain and a feeling of light pressure. In the absence of local anesthesia cream, you feel a short sharp pain. The cannula is secured to the skin with tape and may be attached to an intravenous ‘line’ or long clear plastic tube connected to a bag of saline or similar fluid. This fluid may feel cold when it runs into the vein (usually in your arm).

Your anesthesiologist may then have you breathe oxygen from a mask. This process is known as preoxygenation. Your anesthesiologist may also give you one or more medications, before giving you the actual medication which makes you lose consciousness. For example, if you are scheduled to have your gallbladder removed, your anesthesiologist might start by giving you an injection of a medication to relax you, and then another medication to decrease the chance of postoperative vomiting. You might also be given an injection of a potent pain-reliever (opiate or narcotic), such as fentanyl. This medication also helps minimise any marked rises in heart rate and blood pressure that can occur at a slightly later stage of anesthesia and surgery. Sometimes anesthesiologists give these additional medications after you have lost consciousness.

The anesthesiologist then injects the induction medication through the cannula into your vein. This is the time when he or she may ask you to count (often backwards, from 100). Counting is a means of distracting you and also shows when the medication has achieved its effect. The induction medication works very quickly, especially in younger patients. It takes only the time for the blood carrying the medication to return from the arm to the heart and then be pumped through the lungs, back to the heart, and then to the brain. (Anesthesiologists call this the ‘arm-brain circulation time’.) In most people this time is about ten seconds, but it may be faster in children and slower in elderly or very ill patients.

Inhalation (gas) induction

This method is common in children but is also used in some adults. It involves having the anesthesiologist or the patient hold a mask over the patient’s nose and mouth. The patient then breathes in a mixture of gases through the face mask until loss of consciousness occurs. Induction by mask usually takes longer than the intravenous method, and achievement of the appropriate depth of anesthesia is often preceded by a period of restlessness. This is quite normal and the patient is already unconscious at this time.

Then the anesthesiologist has an assistant (nurse, technician or another anesthesiologist) hold the mask and ensures that the patient is continuing to breathe well. The anesthesiologist then inserts an intravenous cannula (as above), unless one has previously been started. This is more likely to have been done in adults. From this point, anesthesia is similar, whether an intravenous or inhalation technique has been used.

Not just a recipe !

How does your anesthesiologist know how much to give you?

Individuals vary in their requirements for anesthesia medications. The dose of the induction medication is generally given slowly to patients who are to have an elective operation. Your anesthesiologist has calculated the expected dose you should need, from your weight, your age, your sex, and your state of health. However, as the medications are injected, the dose of each is adjusted as necessary, according to the effects produced. This is known as titrating the medications according to their effect. In an emergency it is sometimes necessary to give the medications quickly, and a predetermined dose is calculated.

Will you have the same anesthesia as the patient in the bed next to you?

Every anesthesia given is a very individual thing and each anesthesia depends on the patient to whom it is given. The doses of medications that you are given are calculated according to your weight, age and state of health; the operation or examination for which it is given; and even the anesthesiologist who gives them. There is no fixed recipe.

What happens once you are asleep?

After the induction medication has caused you to lose consciousness, your anesthesiologist gives you one or more other medications (a mixture of pain-relievers, sedatives, and anesthesia gases) to ensure that you remain unconscious. If these other anesthesia agents were not given, you would regain consciousness in a few minutes, after the induction medication had worn off.

Breathing during anesthesia

Once you are unconscious, your anesthesiologist will take over the management of your breathing, while attending to any changes in your pulse, blood pressure and the amount of oxygen in the blood. This management might consist of holding the mask over your mouth and nose, ensuring that you are breathing clearly and without snoring; or holding the mask and breathing for you by squeezing a bag attached to the breathing circuit; or inserting a breathing tube into your mouth.

Throughout the operation you are given oxygen, first with the mask, and then usually through a plastic airway. There are several types of airway, each of which is a different size, depending on your age and size. The presence of an airway helps to ensure that your breathing is adequate and, in the case of an endotracheal (breathing) tube, that acid from your stomach does not pass into your lungs.

Muscle relaxation

To help manage your breathing, your anesthesiologist might inject a muscle relaxant, to relax or weaken your throat and abdominal muscles. Muscle relaxants have two major useful effects.

•They make it easier for your anesthesiologist to insert a breathing (endotracheal) tube through your mouth or, on occasion, through your nose, into your trachea or windpipe. (This process is known as tracheal intubation.) Without muscle relaxants, your anesthesiologist would have to give higher doses of other medications so as to weaken the muscles of your mouth and throat, to make insertion of the tube (intubation) easier.

•They actually make it possible for the surgeon to perform many operations, without causing any damage to muscle fibres. Indeed, it is difficult for a surgeon to operate inside your abdomen if the muscles are not relaxed. The same applies to other operations, such as those on the hip or in the chest, but not for those on the skin or the body surface.

If you have been given a muscle relaxant, all of your muscles will be relaxed or weakened, including the muscles that help with breathing. In that case, your anesthesiologist ‘breathes for you’. This is usually done with a ventilator, which pushes gas around the anesthesia circuit and into your lungs. Ventilation may also be done by hand, with your anesthesiologist squeezing a bag attached to the anesthesia circu

Airways and breathing tubes

The smallest airway is the oral airway. An average adult airway is about four inches (ten centimetres) in length and one-half inch (one centimetre) in diameter and is curved to fit over the back of the tongue. An oral airway is most often used for minor operations, such as those on a limb, particularly if the duration of the procedure is to be short. The laryngeal mask airway is longer and fits over the top of the larynx. Many anesthesiologists now use the laryngeal mask for cases for that would previously have had an oral airway and for cases that may have required an endotracheal tube.

The endotracheal tube is long enough to reach from just outside your mouth or nose and down to just below your vocal cords. The decision to use an endotracheal tube is determined by your condition, the operation to be performed, and the position in which you are placed during the operation. Usually, an endotracheal tube is used if the surgeon is to operate on the brain, the head and neck region, the chest, the back, the abdomen, or the pelvis. Although anesthesia is started while you are lying on your back, your surgeon may need you to be in a different position for the operation. For example, if you are to have an operation on your back, the Operating Room team will turn you over onto your stomach after you are unconscious and an endotracheal tube has been inserted.

An airway is placed in your mouth after you become unconscious, although rarely an endotracheal tube must be inserted before any medications are given and you are still conscious. This is known as ‘awake intubation’ and is only likely if you have a tumour or severe obstruction in your throat.

Awake intubation

Before placement of an endotracheal tube while still conscious, you would be given a solution of local anesthesia to gargle, which numbs your mouth and throat, and decreases any gagging or coughing as the tube is inserted. Your anesthesiologist would explain the process beforehand.

If your anesthesiologist has chosen to use a laryngeal mask or endotracheal tube, it is connected to the circuit after it has been inserted. Your anesthesiologist controls and monitors the flow and concentration of gases that enter and leave the circuit and your body, so that you receive the appropriate amount of anesthesia and breathe adequately.

How does your anesthesiologist know that the tube is where it should be?

If the anesthesiologist has inserted an endotracheal tube into your trachea (windpipe), you breathe carbon dioxide out through the tube. (Carbon dioxide is the gas produced by the body as it uses oxygen to generate energy. Carbon dioxide is then excreted from the body through the lungs.) Carbon dioxide can be measured with a specific monitor, normally attached to the endotracheal tube. The presence of carbon dioxide in the endotracheal tube suggests that the tube is in your trachea.

There are other methods to help confirm the correct position of the tube, but they are less accurate than the carbon dioxide monitor. Your anesthesiologist might also use a stethoscope to listen for the sounds of air moving in and out of your lungs on both sides of your chest and carefully observe how your chest moves up and down with each breath, noting whether or not this movement is symmetrical, which usually occurs when the tube is in the trachea.

Your anesthesiologist might also listen to your chest to ensure that the tracheal tube has not been placed too far down into one lung. This is known as an endobronchial intubation and is sometimes done on purpose. If the surgeon wants to operate on the left lung, then the tube is intentionally placed into the right lung.

Induction of anaesthesia in children

Children vary greatly in the way they react to induction of anesthesia. All children exhibit fear in some way, because of the strange environment, separation from their parents, and the uncertainty about what is to happen to them.

Less than six months

Less than six months

Infants of less than six months do not react strongly to being separated from their parents and usually respond appropriately to a parent substitute. The anesthesiologist should be accustomed to caring for small children and, together with other staff, be empathetic with both child and parents.

It is uncommon for parents to accompany infants of less than six months during induction of anesthesia. This is for two reasons: a child of this age does not suffer major separation anxiety; and everything occurs much more quickly in a baby. This includes the action of medications and the need to act to correct problems such as breath holding. The anesthesiologist must devote his or her whole attention to the child without also having to be concerned about parents.

Six months to four years

Children in this age group do not tolerate separation from their parents well and are not able to comprehend explanation. They react to the unknown with fear, withdrawal and struggling. Induction of anesthesia is best performed either with a parent present, or premedication, or both. With a parent present, the child tends to cling. Induction of anesthesia can be difficult in this age group. Adequately sedated, there is little problem and usually no recollection of events. However, the sedative medications may prolong the recovery phase and delay discharge from hospitals after minor or day stay operations.

With a parent present, either an intravenous or inhalation (gas) induction may be used. For intravenous induction, the parent is asked to hold the child firmly, with the parent either sitting on a chair or leaning over the child who is in a cot or on a bed. The parent is then asked to interact with the child by talking, singing or playing with a toy. At the same time, an assistant secures an arm or a leg where local anesthesia cream has been applied, while the anesthesiologist inserts a cannula.

Inhalation induction is preferred by some anesthesiologists. However, usually a mask cannot be placed over a child’s face without a struggle. Sometimes this struggle may be minimised by the anesthesiologist applying a few drops of a common food flavouring, such as strawberry, orange or bubblegum, to the mask. These scents help to disguise the smell of the anesthesia gases. Alternatively, some anesthesiologists use their hand as a mask. Induction by mask takes longer than intravenous induction.

Four to six years

Children in this age group are still anxious about separation but are more accepting of explanations and reassurance. As with younger children, they benefit from having a parent present during induction, although less physical restraint is required.

Six to ten years

Children aged six to ten years have less of a problem with separation from parents and are much more amenable to reassurance. They do, however, fear anesthesia and surgery, and particularly pain. They may have fantasies of mutilation and require reassurance about the exact nature of the operation. They will be irritable and impatient.

Intravenous induction is usually well tolerated, although the fear of needles may be so strong that even application of local anesthesia cream is not enough to overcome the fear. Cooperation can usually be obtained for an inhalation induction with a mask. Sometimes a child indicates a preference, especially if he or she has had previous anesthesias.

The presence of a parent or guardian can be of great assistance to the child and the anesthesiologist.

Adolescents

This group of patients may fear loss of control and death. It is important to reassure them of the safety of modern anesthesia and that they can be in control of their pain management after the operation.

Intravenous induction is commonly used in adolescents. However, some patients request an inhalation induction, particularly if they have undergone several (or multiple) operations.

Your role as a parent during the induction of anesthesia

You can be an enormous help during induction of your child’s anesthesia. Your presence, in most cases, means a calmer, more cooperative patient, with less likelihood of bad memories of the hospitalisation.

There are several points to consider. Just as your child needs to be prepared for the event, so you need to learn as much as you can about what will happen.

Part of your preparation includes recognising that you, too, may be distressed by the experience. The final decision rests with the anesthesiologist as to your presence. Although many anesthesiologists are now used to having parents present at induction, some find their presence stressful. For the child’s safety, an anesthesiologist may prefer not to have this added distraction.

Your presence may not be encouraged in every situation. This applies particularly if your child needs an emergency operation. Should something happen, such as your child vomiting, then the anesthesiologist needs to focus attention on the child.

You should not feel pressured to be involved. Not everyone is comfortable with the idea of staying during induction and you are free to decline the invitation. Your child’s care will be no less professional.

You should be prepared for your child’s appearance after induction. Your child will become anesthetized within seconds and may suddenly look lifeless, but often with the eyes still open. This is normal. At the same time the anesthesiologist will be concentrating on the next step in the process of caring for your child. He or she usually cannot talk with you or to answer questions at that time.

You should go when asked to leave.

Emergency induction of general anaesthesia

Your anesthesiologist might modify the induction of anesthesia by using a technique known as a ‘ rapid sequence induction’. This is a crucial technique in patients who must undergo an emergency operation and who have a full stomach, either because they have just eaten or because their stomachs take longer than normal to empty (as a result of pain, medications, or other conditions).

In a rapid sequence induction, you are given 100 per cent oxygen to breathe from a mask placed firmly over your mouth and nose for three to four minutes. This process is known as preoxygenation and replaces the nitrogen in your lungs (the most common gas in the air) with oxygen. As a result, the store of oxygen in your body is markedly increased and there is less chance of lack of oxygen ( hypoxia).

In the next step your anesthesiologist calculates the dose of two medications – the induction medication (usually propofol or pentothal) and a rapid-acting muscle relaxant. The dose of each medication is calculated on the basis of your weight and your general condition.

Your anesthesiologist then injects the two medications rapidly through the intravenous cannula and you quickly lose consciousness. This minimises any risk of your going through a stage during the loss of consciousness when you struggle or vomit.

As you lose consciousness, your anesthesiologist instructs an assistant to apply firm pressure to the front of your neck. The assistant normally stands on your right and uses the first three fingers of the right hand to apply the pressure. (You might feel the assistant’s fingers lightly touching your neck as you lose consciousness.) The specific part where the pressure is applied, called your cricoid cartilage, is a ring of cartilage that forms part of your trachea. Pressure on the cricoid cartilage ( cricoid pressure) seals off the esophagus and reduces the possibility of stomach contents flowing from the esophagus into the back of the throat and then down into the lungs.

Maintenance of anaesthesia (“keeping you asleep”)

During the maintenance phase of anesthesia, your anesthesiologist keeps you in a state of unconsciousness, using a mixture of inhaled (inhalational) and intravenous (injected) medications. The inhalational agents are administered through the breathing circuit. They include nitrous oxide and the ‘volatile’ anesthesia agents (because they pass easily from being a liquid to a gas). The volatile anesthesia agents are commonly used in proportions between 0.5 and 4 per cent, although this varies according to the agent and the desired effect. They are powerful medications and are used to keep you unconscious, as well as helping to control pain and to relax muscles. These medications can also have side effects, such as low blood pressure, changes in heart rhythm, and difficulties with breathing.

Nitrous oxide (N2O) or (‘laughing gas’) is often used in general anesthesia, in a mixture with oxygen of around 70 per cent nitrous oxide and 30 per cent oxygen. At that concentration the nitrous oxide may make you sleepy and able to tolerate mildly painful procedures, but that is all. Nitrous oxide does, however, provide a means of giving other stronger anesthesia gases through the breathing system.

Air, enriched with extra oxygen, is sometimes used when nitrous oxide is less desirable, such as during anesthesia in the elderly, for some brain surgery, some major heart and lung surgery, and in some tiny premature infants. Usually during anesthesia, oxygen is added so that the usual proportion given to the patient is about 30 per cent. This extra oxygen provides some safety margin over the normal 21 per cent in room air. The critical aspect of anesthesia care is to ensure that you continue to receive adequate oxygen, which is necessary for preservation of life and the functioning of organs.

Your anesthesiologist may choose to give you other medications through the intravenous line. Depending on the medication, your anesthesiologist may do this to increase the depth of the anesthesia (how unconscious you are). Medications are also given to provide pain relief after the operation. If the surgeon needs your muscles to be relaxed (in order to perform the procedure), your anesthesiologist may give you further doses of the muscle relaxant medication given at the time of induction, or a different medication. Intravenously administered medications may be given in separate or discrete doses (sometimes known as 'bolus' doses) or by constant injection or 'infusion' regulated by a pump.

Sometimes your anesthesiologist will not use any inhalation anesthesia at all. When all anesthesia medications are given intravenously, it is referred to as Total Intravenous Anesthesia, or TIVA. These medications are usually given by carefully controlled infusion.

emergence (“waking up”)

The third phase of the general anesthesia is emergence or regaining consciousness. During this phase your anesthesiologist stops giving you all inhalational anesthesia agents (except the oxygen) and also stops any intravenous anesthesia medications. You gradually regain consciousness. Your anesthesiologist usually needs to reverse the effects of the muscle relaxants, with the injection of two more medications. As consciousness returns, your anesthesiologist makes sure that you can breathe without help. Once you are regaining consciousness and able to breathe without any help from the anesthesiologist, the breathing tube is removed. By carefully calculating the right amounts of each medication, your anesthesiologist can ensure that you are completely unconscious during the operation, but awake and pain-free at the end of the procedure.