Anesthetic Problems and Emergencies A&A Chapter 12 pg. 319- 349

Why Do Problems Arise? Human error Equipment error Drug adverse effects Patient factors Anesthetic problems will inevitably occur at some point in your career. No anesthetic experience is the same, so beware of the false sense of security!

Human Error Failure to obtain an adequate history or physical exam on the patient Ideally, every patient scheduled for anesthesia should have a complete PE, and a thorough history obtained with the owner present. *Less than ideal circumstances are common: Owner drops patient off in a hurry Patient brought in by neighbor or friend Receptionist takes the history HISTORY?

Human Error Lack of familiarity with the anesthetic machine or drugs

Human Error Fatigue Distracted or rushed Inattentiveness Proper scheduling of surgeries can help with this Distracted or rushed Usually you have your surgical patient and… Inattentiveness Having a low level of anxiety is good!

Human Error Incorrect administration of drugs Inaccurate weight Math errors – calculating OR drawing up Use of wrong medication Use of wrong ______________ Ex: enrofloxcain, ketamine, dexamethasone, bupivicaine Incorrect route of administration IV v. IM Confusion between syringes

Equipment Failure CO2 ABSORBER EXHAUSTION Exhausted granules can cause your patient to rebreathe what exhaled gas? How is CO2 removed from a rebreathing system? How is CO2 removed from a non-rebreathing system? Best ways to keep an eye on exhaled CO2? If using insofluane- ↑ CO2 (hypercapnia)= Tachypnea, tachycardia, cardiac arrhythmias

Equipment Failure NO OXYGEN FLOW Which two parts of the machine may be malfunctioning? Oxygen tank: check for empty tank, disconnected hose, leaks Flow meter: will gradually fall as the O2 tank empties Periodically check this! *Which breathing system can go without new O2 flow longer?

Equipment Failure ANESTHETIC MACHINE MISASSEMBLED The better you know this machine and the flow of gas, the quicker you will be able to solve problems. *Where do some of the most common misassembled parts happen on the machine?

Equipment Failure ENDOTRACHEAL TUBE PROBLEMS Blocked tube Twisting or kinking of the tube (inappropriate positioning) Accumulation of material such as blood, mucus, excess lubricant Solution: Check signs of tube properly in the trachea *If truly blocked  Magill, non-murphy eye

Equipment Failure ENDOTRACHEAL TUBE PROBLEMS Tube advanced too far into a bronchus Solution: Air is heard escaping during PPV/can smell inhalant Deflate first!

Equipment Failure Wrong anesthetic in the vaporizer VAPORIZER PROBLEMS Wrong anesthetic in the vaporizer Non-precise concentration will be delivered Solution: Tipped over or over-filled Vaporizer dial may be jammed

=rupture of lungs and decreased venous return to Equipment Failure POP-OFF VALVE PROBLEMS The pop-off valve is inadvertently left closed  pressure builds  patient cannot exhale  =rupture of lungs and decreased venous return to Reasons why pop off would be closed?? Solution:

Anesthetic Agents “Every injectable or inhalation agent has the potential to harm a patient and, in some cases, cause death”. (Page 323) Review the description of the physiological effects of pre-anesthetic and general anesthetic agents in chapter 3.

Anesthetic Agents Anesthetic protocol should be chosen based on the patient’s needs Anesthetist must be familiar with drug side effects Such as? Understand why balanced anesthesia is safer!

Patient Factors Pages 323-334 Reproductive status Weight Breed Trauma Organ disease ASA Physical Status Classification Patient description and examples Potential problems Solutions

Geriatric Patients POTENTIAL PROBLEMS 1. Reduced organ function ASA P2 (75% of life expectancy) POTENTIAL PROBLEMS 1. Reduced organ function Increased risk for hypervolemia Prolonged recovery 2. Higher risk for degenerative disorders Ex: cancer, cardiac disease, diabetes 3. Poor response to stress 4. Increased risk for hypothermia- reduced ability to thermoregulate

Geriatric Patients ASA P2 (75% of life expectancy) POTENTIAL SOLUTIONS

Pediatric Patients ASA P2 (<3 months of age) POTENTIAL PROBLEMS 1. Increased risk for hypothermia- can’t shiver, lack of body fat; high body surface area 2. Over hydration common 3. Increased risk of hypoglycemia, hypotension, bradycardia 4. Inefficient excretion of drugs- non developed liver 5. Difficult intubation and IV cath placement 6. Unpredictable response to atropine <14 days

Pediatric Patients ASA P2 (<3 months) POTENTIAL SOLUTIONS

Brachycephalic Patients ASA P1 Pug, Pekingese, Boston Terrier, etc. POTENTIAL PROBLEMS 1. Conformational tendency toward airway obstruction Elongated soft palate w/ redundant tissue Small nasal openings Small diameter trachea 2. Abnormally high vagal tone (parasympathetic) Bradycardia common Ocular surgery consideration?

Brachycephalic Patients ASA P1 Pug, Pekingese, Boston Terrier, etc POTENTIAL SOLUTIONS

Sighthounds POTENTIAL PROBLEMS ASA P1 Greyhound, afghan hound, whippet, borzoi, saluki, Russian wolfhound POTENTIAL PROBLEMS Increased sensitivity to barbiturates (ex. thiopental) Highly lipid soluble drugs that leave brain for fat Hounds- lack of body fat for redistribution/elimination of the drug  drug stays on the brain longer SOLUTION

Obese Patients POTENTIAL PROBLEMS ASA P2 Body condition score 5/5 POTENTIAL PROBLEMS 1. Accurate dosing is difficult based on weight Poor distribution of drugs- no blood supply to fat 2. Respiratory difficulty; rapid shallow resps

Obese Patients ASA P2 Body condition score 5/5 POTENTIAL SOLUTIONS

Cesarean Patients POTENTIAL PROBLEMS ASA P1 1. Increased workload to heart 2. Respiration compromised due to decreased lung capacity- fetuses pressing on diaphragm 3. Increased risk of hemorrhage from uterus- already anemic from RBCs going to fetuses 4. Physiologic anemia- high plasma but not RBC 5. Increased risk of vomiting/regurgitation- not fasted 6. Decreased Ax requirement- increased progesterone already stimulates GABA receptors (inhibitory) 7. Fetuses will receive drugs

Cesarean Patients ASA P1 POTENTIAL SOLUTIONS

Trauma Patients POTENTIAL PROBLEMS Respiratory distress Examples: ASA P3, P4 or P5 POTENTIAL PROBLEMS Respiratory distress Examples: Pneumothorax: air in pleural space No negative pressure = lung collapse Pleural effusion: fluid in pleural space Fluid compressing lung expansion = lung collapse Pulmonary contusions/edema: fluid in lung parenchyma Fluid in alveoli = no gas exchange

Trauma Patients POTENTIAL SOLUTIONS Respiratory distress ASA P3, P4 or P5 Respiratory distress POTENTIAL SOLUTIONS

Trauma Patients POTENTIAL PROBLEMS Solution: 3. Shock/hemorrhage 2. Cardiac arrhythmias Solution: 3. Shock/hemorrhage 4. Fractures/organ rupture  blood loss 5. Unknown internal injuries

Patients w/ Cardiovascular Disease ASA P3, P4, P5 POTENTIAL PROBLEMS 1. Circulation compromised 2. Pulmonary edema common 3. Increased tendency to develop arrhythmias

Patients w/ Cardiovascular Disease ASA P3, P4, P5 POTENTIAL SOLUTIONS

Patients w/ Respiratory Disease ASA P3, P4, P5 POTENTIAL PROBLEMS 1. Poor oxygenation of tissues 2. Patient may be anxious and difficult to restrain 3. Increased risk of respiratory arrest

Patients w/ Respiratory Disease ASA P3, P4, P5 POTENTIAL SOLUTIONS

Patients w/ Hepatic Disease ASA P3, P4, P5 POTENTIAL PROBLEMS 1. Delayed metabolism of drugs filtered through liver 2. Increased potency of barbituates (unbound drug molecules go to brain) 3. Decreased synthesis of clotting factors and proteins = coagulation issues and hypoproteinemia 4. Icteric 5. Improper glycogen/gluconeogenesis  hypoglycemia

Patients w/ Hepatic Disease ASA P3, P4, P5 POTENTIAL SOLUTIONS

Patients w/ Renal Disease ASA P3, P4, P5 POTENTIAL PROBLEMS 1. Delayed excretion of anesthetic agents 2. Electrolyte imbalances common 3. Dehydration may be present

Patients w/ Renal Disease ASA P3, P4, P5 POTENTIAL SOLUTIONS