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The Ultimate Study Guide: Anesthesia Review

5th Edition

Ultimate Study Guide!

©ANESTHESIA HQ 2007! 1

Copyright © 2007, 2006, 2005, 2004, 2003 by The Sock Lake Group, LLC

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" Ultimate Study Guide

2! ©ANESTHESIA HQ 2007

Preface to the 5th Edition

My initial motivation in creating the Ultimate Study Guide board review series and Anesthesia HQ was to create a concise, current and comprehensive study guide for those preparing for the anesthesia board exams. This fifth edition of the Ultimate Study Guide maintains my initial goal and with the combination of the website, www.anesthesiahq.com, offers a unique learning experience for those preparing for the anesthesia board exams.

The Ultimate Study Guide is still organized by topics and chapters in an easy to read outline format, which also will provide you with the opportunity to add your own knowledge, thoughts, and comments throughout the review process. The Ultimate Study Guide is intended as a supplement and an aid to your previous years of study, diligence, and hard work. Although no one truly knows the exact topics and knowledge that may be tested on the anesthesia board exam in any given year, there are certain topics which are tested in each anesthesia board exam. From the moment you begin preparing for the anesthesia board exam, you should read, reread, and review again, all of the topics and information contained in the Ultimate Study Guide.

My goal is to provide you with the tools to prepare, organize, and ultimately pass the anesthesia board exams. I wish you good luck and success in your studies and career.

Michael K Loushin, MDFounder and OwnerAnesthesia HQ





Dedication

To my loving family, Ann, Noah, and Ella. They make everything possible.



Notice of Liability

The information contained herein is only to be used as a study aide in preparation for the anesthesia board exams. Such information is not to replace any medical education, clinical experiences, or the study of textbooks and medical journals. The actual use of this information, including any medical concepts, facts, drug dosages, and methods, therefore is at the reader!s own risk. We assume NO responsibility for any injury or damages to any person or property that may result from such reliance on or use of any of this information.

We have taken all reasonable precautions to confirm the accuracy of the information presented herein and to describe generally accepted practices. However, we are not responsible for any inaccuracies, errors, and/or omissions or for any consequences from the use or application of any of the information contained herein and make no promise or warranty, express or implied, with respect thereto.

We have taken all reasonable precautions to ensure that the drug selection and dosages set forth in this text are in accordance with recommendations and practice current at the time of writing. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is solely responsible for reviewing and following the package insert for each drug for any change in indications and dosage and for any warnings and precautions. This is particularly important when the recommended agent is a new or infrequently employed drug.

Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings. It therefore is the sole responsibility of the reader to ensure that the applicable health care provider has ascertained the FDA status of each drug or device planned for use in their clinical practice.

THE READER ASSUMES ANY AND ALL RISKS ASSOCIATED WITH THE ACTUAL USE AND/OR RELIANCE ON ANY OF THE INFORMATION CONTAINED HEREIN THAT DEVIATES IN ANY WAY FROM THE INTENDED PURPOSE OF SUCH INFORMATION AS ONLY A STUDY AIDE IN PREPARATION OF THE ANESTHESIA BOARD EXAMS. TO THE EXTENT THE READER ULTIMATELY RELIES ON AND/OR OTHERWISE USES ANY SUCH INFORMATION FOR ANY OTHER PURPOSE, WHETHER INTENDED OR OTHERWISE, THE READER AGREES TO INDEMNIFY AND HOLD US HARMLESS FROM ANY AND ALL INJURIES, DAMAGES, COSTS, FEES AND EXPENSES (INCLUDING ATTORNEYS! FEES AND EXPENSES) THAT MAY OR DOES IN ANY WAY RESULT FROM SUCH ACTUAL USE AND/OR RELIANCE.



Table of Contents

Anesthesia Circuits and Machines" 13

Bellows" 27

Vaporizers" 35

Scavenger System" 45

E Cylinders" 53

Carbon Dioxide Absorbers" 59

Electricity " 65

Capnography " 73

Blood Pressure Monitoring" 87

Central Venous Pressure Monitoring" 97

Pulmonary Artery Catheter" 105

Cardiac Output & Cardiac Index Monitoring" 115

Pulse Oximetry " 123

Mixed Venous Saturation Monitoring" 129

Cardiac Pressure-Volume Curves" 135

Inhalational Anesthetics" 145

Neuromuscular Blockers" 161

Local Anesthetics" 175

Obstetric Anesthesia: An Overview " 185

Obstetric Emergencies" 195

Pre-eclampsia" 203

Fetal Heart Tracing" 209

Myocardial Ischemia & Myocardial Infarction" 219

Valvular Diseases" 229

Pacemakers & Automated Implantable Cardiovertor Defibrillators" 245

Anesthetic Management of Pacemakers & AICDs" 251

Cardiac Reflexes" 255

Abdominal Aortic Aneurysm" 259

Thoracic Aortic Aneurysm" 267

Intra-aortic Balloon Pump" 273

Cardiopulmonary Bypass Circuit" 279

Respiratory: An Overview" 287

Hypoxemia" 303



Thoracic Anesthesia" 309

Mediastinoscopy " 323

Cystic Fibrosis" 327

Obstructive & Restrictive" 331

Lung Diseases" 331

Aspiration" 343

Acid-Base: An Overview " 349

Metabolic Acidosis" 359

Metabolic Alkalosis" 367

Respiratory Acidosis" 371

Respiratory Alkalosis" 379

Alpha-stat & pH-stat" 383

Blood Gas Management" 383

Neuroanesthesia" 387

Evoked Potentials " 401

Carotid Endarterectomy " 407

Arnold-Chiari Malformation" 415

Venous Air Embolism" 417

Spine Anatomy " 421

Spinal Cord Injury & Spinal Shock" 431

Tourniquet Pain" 437

Pediatric Anesthesia & Physiology " 441

Congenital Diaphragmatic Hernia" 455

Necrotizing Enterocolitis" 459

Ligation of a Patent Ductus Arteriosus " 463

Pyloric Stenosis" 467

Retinopathy of Prematurity " 471

Tracheo-esophageal Fistula" 475

Gastroschisis & Omphalocele" 481

Extracorporeal Membrane Oxygenation" 485

Ophthalmology & Eye Physiology " 489

Retrobulbar Block" 497

Perioperative Eye Injury " 501

Endocrine" 505

Thyroid Hormone" 511



Parathyroid Hormone" 519

Pheochromocytoma" 525

Obesity " 533

Liver Physiology " 539

Geriatrics " 543

Temperature Regulation during Anesthesia" 547

Malignant Hyperthermia" 553

Neuroleptic Malignant Syndrome" 559

TURP Syndrome" 563

Extracorporeal Shock Wave Lithotripsy " 569

Coagulopathies" 573

Hemoglobinopathies" 581

Porphyrias" 587

Scleroderma" 593

Scoliosis" 597

Parkinson!s Disease" 603

Systemic Lupus Erythematosus " 607

Osteogenesis Imperfecta" 613

Myotonic Dystrophy " 617

Muscular Dystrophy " 621

Multiple Sclerosis" 625

Myasthenia Gravis " 629

Myasthenic (Lambert-Eaton) Syndrome" 635

Guillain-Barre Syndrome" 639

Amyotrophic Lateral Sclerosis" 643

Carcinoid Syndrome" 647

Coexisting Diseases" 651

Airway & ENT" 657

Acute Epiglottitis" 665

Blood Transfusion" 669

Transfusion Reaction" 681

Isovolemic Hemodilution" 687

Heparin-Induced Thrombocytopenia" 693

Chemotherapeutic" 697

& Immunosuppressant Drugs" 697



Electroconvulsive Therapy " 701

Burns" 705

Pain and Regional Anesthesia" 713

Intraoperative Awareness and Depth of Anesthesia" 739

Statistics " 743

Gauge and French Conversion" 749

Equations" 751

Anticholinergics " 763

Antiplatelets" 766

Barbiturates" 767

Benzodiazepines" 769

Beta Blockers" 771

Cholinesterase Inhibitors " 773

Clonidine" 776

Digoxin" 778

Dobutamine" 780

Dopamine" 781

Droperidol" 782

Ephedrine" 784

Epinephrine" 785

Etomidate" 787

Fenoldopam" 788

Fentanyl" 789

Glucagon" 790

H-2 Receptor Blockers" 791

Heparin" 792

Hydralazine" 793

Isoproterenol" 794

Ketamine" 795

Meperidine" 797

Metoclopramide" 798

Milrinone" 799

Morphine" 800

Naloxone" 801

Nicardipine" 802



Nitric Oxide" 803

Nitroglycerin" 804

Nitroprusside" 805

Norepinephrine" 807

Phentolamine" 808

Phenylephrine" 809

Prazosin" 810

Propofol" 811

Succinylcholine" 813

Sufentanil & Remifentanil" 815

Sympathomimetics" 816

Trimethaphan" 817

Index" 819





! Anesthesia Circuits and Machines

A. Circle systems are complex anesthesia circuits where the components are arranged in a “circle”. Circle systems are utilized to prevent rebreathing of carbon dioxide (CO2) during low fresh gas flow. They also allow good conservation of respiratory heat and humidity.

B. Circle systems prevent rebreathing of carbon dioxide by means of a CO2 absorber. They allow rebreathing of exhaled gases (oxygen and anesthetic gases). A scavenger system removes any waste gases from the circle system.

C. A circle system can be semi-closed, semi-open, or closed.

1. Semi-open system does not allow rebreathing of gases and requires very high fresh gas flow rates.

2. Semi-closed system allows rebreathing of gases and can be used with low fresh gas flow rates.

3. Closed system allows rebreathing of gases, and the inspiratory and expiratory volumes are essentially matched. A semi-closed system can be converted into a closed system by closing the adjustable pressure limiting (APL) or “pop-off” valve.

D. A semi-closed system allows rebreathing of gases.

1. It is the most common anesthesia system used in the United States.

2. Due to circuit and multiple valves, a semi-closed system has more resistance to breathing during spontaneous ventilation.

3. Multiple valves are present in the breathing circuit of a semi-closed system.

4. Reservoir (breathing) bag is part of the breathing circuit.

5. With a semi-closed system, it is still possible to rebreathe CO2.

6. Administration of low fresh gas flow rate can be utilized with a semi-closed system.

E. A semi-open system does not allow rebreathing of gases and requires high fresh gas flow.

1. Mapleson systems are semi-open systems.

Ultimate Study Guide! Chapter: Anesthesia Circuits and Machines


2. Semi-open systems are associated with increased loss of heat and humidity due to high fresh gas flow rates and absence of rebreathing.

3. It is difficult to scavenge waste gases with a semi-open system.

4. Since they do not contain valves, semi-open systems have less resistance to spontaneous breathing.

F. A closed system has fresh inflow gas which nearly equals the amount of gas taken up by the patient.

1. The amount of inflow gas that needs to be replaced is the amount of oxygen consumed by the patient and the amount of anesthetic gas absorbed by the patient!s body and the anesthesia circuit.

2. There is complete rebreathing of gases (oxygen and inhalational anesthetic) after removal of CO2 by the carbon dioxide absorber.

3. There is no gas exiting through the scavenger.

4. The APL valve is also closed, preventing overflow of gases.

5. Some of the semi-closed systems may be turned into closed systems by turning the APL valve to the off/closed position.

6. Since there is nearly complete rebreathing of gases, a closed system offers maximum conservation of heat and humidity.

7. A change in gas concentration occurs very slowly, due to low fresh gas flows.

G. A circle system requires the following components.

1. Fresh gas inlet

2. Tubing for expiratory and inspiratory limbs

3. Reservoir (ventilating) bag

4. Adjustable pressure limiting (APL) valve

5. Unidirectional valves on expiratory and inspiratory limbs

6. Carbon dioxide absorber

7. Y-piece that connects the inspiratory and expiratory limbs of the circuit

Chapter: Anesthesia Circuits and Machines " Ultimate Study Guide


H. The components of the circle system may be arranged in multiple ways, but certain criteria must be met in order to prevent rebreathing of carbon dioxide.

1. The fresh gas inlet must be between the CO2 absorber and inspiratory valve. It cannot be on the expiratory limb.

2. The adjustable pressure limiting valve (APL) must be between the CO2 absorber and expiratory valve. It cannot be in the inspiratory limb.

3. The unidirectional valves must be present between the reservoir bag/bellows and the patient (Y-piece).

4. Other components of the circle system may have varying configurations.

I. Advantages of a circle system include the following:

1. Conservation of respiratory heat and humidity

2. Ability to scavenge waste gases

3. More constant concentration of inspired anesthetic gases

4. Allows administration of very low fresh gas flow without causing rebreathing CO2



5. Economical since it allows rebreathing of exhaled oxygen and volatile anesthetics

J. Disadvantages of a circle system include the following:

1. Greater potential for system leaks and disconnections

2. Risk of malfunctioning unidirectional valves (stuck open or closed)

3. Due to multiple valves and components of the anesthesia circuit, there is increased resistance and work of breathing during spontaneous ventilation.

K. During spontaneous ventilation with a circle system, the APL valve is fully open.

L. In a circle system, the ventilation dead space is distal to the Y–piece of the breathing circuit.

1. The length of the separate inspiratory and expiratory limbs of the tubing does not affect dead space caused by the anesthesia circuit.

2. For example, increasing the length of the inspiratory and expiratory limbs does not increase the dead space distal to the Y-piece.

M. The compliance of the circuit tubing will affect the tidal volume that is delivered to the patient. A portion of a set tidal volume can be lost to distending the circuit tubing.

1. A less compliant tubing results in smaller distention of the circuit tubing with each inspiratory volume.

a. Pediatric and neonatal circuit tubing are less compliant. This minimizes the amount of tidal volume lost to distending the tubing with each delivered ventilation.

b. Anesthesia circuit tubing with low compliance should be used for neonates and infants.

2. For example, if the circuit tubing has a compliance of 5 mL/cm H2O, and the inspiratory pressure is 20 cm H2O, the amount of volume lost to distending the tubing is 100 mL (5 mL/cm H2O multiplied by 20 cm H2O).

a. One can see from the above example how tubing compliance can cause hypoventilation issues in small children and neonates. Depending on the compliance of the lungs, majority of the set tidal volume may be used to just distend the tubing.

b. Using the above example, let!s say a neonate required a tidal volume of 80 mL. Since 100 mL is lost to distending the tubing, the neonate may not receive any lung ventilation. Instead, the set tidal volume would only distend the circuit tubing.



3. Some of the newer anesthesia machines compensate for tubing compliance. The compensatory mechanism allows better matching of set tidal volume to actual delivered tidal volume.

N. Oxygen flush valve is connected inline with the inspiratory limb of the breathing circuit.

1. When the oxygen flush valve is open, fresh gas (oxygen) flows at approximately 50 psi and greater than 30 L/min.

2. Opening the oxygen flush valve can result in the following:

a. Dilute the concentration of an anesthetic gas delivered to the patient.

b. Acutely increase the fraction inspired oxygen (FIO2).

c. When the inspiratory valve is open, activating the oxygen flush valve can increase the risk of barotrauma and pneumothorax.



Mechanical Ventilation: Inspiration

• During mechanical inspiration, the bag/bellows switch is closed to the ventilator bag.

• The scavenger valve is closed during inspiration.

• The inspiratory valve is open.

• The expiratory valve is closed during inspiration.

• Gases from the bellows flows through the CO2 absorber prior to going to the patient.

• The fresh gas inlet also provides fresh oxygen and volatile anesthetics.



Mechanical Ventilation: Expiration

• During mechanical expiration, the bag/bellows switch is closed to the ventilator bag.

• The expiratory valve is open.

• The inspiratory valve is closed during expiration.

• Gases from the patient flow into the bellows.

• The fresh gas also provides the bellows with oxygen and volatile anesthetics.

• Once the ventilation bellows is filled, excess gases are vented to the scavenger.



Manual (Bag) Ventilation: Inspiration

• During manual (bag) ventilation, the bag/bellows switch is open to the ventilator bag and closed to the bellows.

• Once the ventilator bag fills with gases, the excess gases are vented to the scavenger by adjusting the APL valve.

• When the ventilator bag is squeezed, the gases flow through the CO2 absorber and to the patient.

• The fresh gas inlet provides additional oxygen and volatile anesthetics.

• Expiratory valve is closed during inspiration.



Manual (Bag) Ventilation: Expiration

• During manual (bag) ventilation, the bag/bellows switch is open to the ventilator bag and closed to the bellows.

• The exhaled gases from the patient fill the ventilator bag.

• The fresh gas inlet provides additional oxygen and volatile anesthetics to the ventilator bag.

• Once the ventilator bag is completely filled, excess gases are vented to the scavenger by adjusting the APL valve.

• Inspiratory valve is closed during expiration.



O. Currently used anesthesia machines have evolved from simple anesthesia delivery machines into complex ventilators with specialized anesthetic delivery mechanisms that are controlled by powerful computers.

1. Even with the evolution of the complex anesthesia machine, the basic components of an anesthesia machine have not significantly changed. The basic components include the following:

a. Gas supply (oxygen, nitrous oxide, air) is provided by central and E-cylinder sources.

b. Pressure regulators to control the supply of gases from the central and E-cylinder gas sources.

c. Multiple alarms and monitors

d. Gas flow meters

e. Anesthetic agent vaporizers

2. The central gas supply has a safety device called a diameter index safety system (DISS) that helps prevent connection of improper gas lines to the central gas supply source.

a. For example, the DISS helps prevent connection of the oxygen gas line to the nitrous oxide central gas supply. Connection of the nitrous oxide line to the oxygen central supply is also prohibited.

b. The central gas supply has a pressure around 45-55 psi.

3. All E-cylinders also have a safety system that helps prevent connection of the incorrect gas cylinder to the anesthesia machine. This is called the pin index safety system (PISS).

4. The pressure regulators in the anesthesia machine lower the pressure of the delivered gases prior to administration to the patient.

a. Low pressure circuit includes the components of the flow meters, control valves, and vaporizer to the common gas outlet to the patient.

b. Intermediate pressure circuit includes the down-regulated E-cylinders pressure (~45-50 psi) to the flow meters and control valves.

(1) Recall, the normal pressure from the oxygen E-cylinders is approximately 2200 psi and the nitrous oxide pressure is about 740 psi.

5. The fail-safe valve is one of the key safety components of an anesthesia machine. The purpose of the fail-safe valve is to help detect and protect from



the delivery of hypoxic mixtures of gases. The 2000 ASTM F1850-00 standard requires the following for all anesthesia machines: the delivered oxygen concentration shall not decrease below 19% at the common gas outlet; an alarm shall activate within five seconds when pressure decreases below manufacturers specified threshold. Current anesthesia machines have alarms that activate when the pressure falls below 30 psi. There are two types of fail-safe valves, depending on the manufacturer of the anesthesia machine.

a. The Datex Ohmeda anesthesia machines utilizes a pressure sensor shut off valve. With this system, the fail-safe valve is either open or closed. When the pressure of oxygen falls to a set threshold (20 psi), the valve closes and shuts off flow of all gases except oxygen to help detect and protect from the delivery of hypoxic mixture of gases.

(1) The Datex Ohmeda machines also have a second-stage oxygen regulator that allows flow of oxygen from the flow valve control to be constant when the pressure is greater than 12-14 psi.

b. The Drager anesthesia machines use a proportioning system called an oxygen failure protection device (OFPD).

(1) The proportioning system decreases the supply of nitrous oxide as the pressure of oxygen supply decreases. At a critical level, the nitrous oxide supply is shut off.

c. The fail-safe valve does not prevent the delivery of an hypoxic mixture of gases. The oxygen analyzer on the distal end of the anesthesia circuit is the last line of defense in detecting the delivery of hypoxic mixture of gases.



Recommended Reading & Reference:Andrews, JJ, Inhaled Anesthetic Delivery Systems, Anesthesia 5th Edition (Miller R,

ed), Churchill Livingstone, Philadelphia, PA, p.174-206Clinical Anesthesia 3rd Edition (Barash P, Cullen B, Stoelting R, ed), Lippincott

Williams & Wilkins, Philadelphia, PA, p.551-554Miller!s Anesthesia 6th Edition (Miller R, ed), Churchill Livingstone, Philadelphia, PA, p.

273-316.



Sample Questions

K-type question: One or more of the numbered options is correct. (A) if 1,2,3 are correct (B) if 1,3 are correct (C) if 2,4 are correct (D) if only 4 is correct (E) if all are correct

Q1: A semi-closed circle system requires

1. Fresh gas on the expiratory limb

2. Adjustable pressure limiting valve on the expiratory limb

3. Scavenger on the inspiratory limb

4. Reservoir bag between the expiratory limb and CO2 absorber

Multiple choice question: Select the ONE BEST answer for each question.

Q2: Which of the following has the LEAST anatomic dead space?

A. LMA with 4 foot breathing circuit

B. ETT with 4 foot breathing circuit

C. Spontaneous ventilation

D. Spontaneous ventilation with oral airway

E. Spontaneous ventilation with nasal airway

Answers: Q1 – C; Q2 – B



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