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75 Cards in this Set
- Front
- Back
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Define apnea
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no breathing
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Define respiratory arrest
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cessation of respiratory effort
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Define dyspnea
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difficult breathing
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Define tachypnea
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rapid respirations
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Define cyanosis
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bluish discoloration of the mucous membranes
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Define tachycardia
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abnormally fast heart rate
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Define bradycardia
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abnormally slow heart rate
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Define pulse deficit
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difference between the palpable pulse and heart rate
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define cardiac arrest
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cessation of circulation due to failure of heart to contract
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What are Anesthetic Problems & Emergencies?
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Animals that will not stay anesthetized
Animals that are too deeply anesthetized |
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What results from when animals are too deeply anesthetized?
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Apnea
Respiratory Arrest Cardiac Arrest |
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What are the Causes of Anesthetic Problems & Emergencies?
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Human Error
Equipment Failure Adverse Effects of Anesthetic Agents Patient-related Factors |
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What does human error involve?
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Failure to obtain adequate history & examination
Inadequate experience with anesthetic machine Failure to monitor properly Failure to recognize and respond promptly to early signs of patient difficulty |
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What is a major, common cause of anesthetic emergencies?
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Human error
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What constitutes equipment issues?
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-Soda Lime Granule Exhaustion
-Empty O2 Tank -Mis-assembly of Anesthetic Machine ---Loose hoses ---Wrong size “Y” piece ---Wrong size rebreathing bag -Endotracheal Tube problems -Vaporizor Problems -Pop-Off Valve Problems |
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What is anesthetic protocol based on?
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The individual patient
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What is safer than anesthesia with a single drug?
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Multidrug use to achieve balanced anesthesia
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What are Patient-Related Factors?
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Geriatric patients
Pediatric patients Brachycephalic dogs Sighthounds Obese animals C-section Trauma patients Patients with organ disease |
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What questions should you ask when an animal will not stay anesthetized?
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Is anesthetic machine assembled correctly?
---Vaporizer turned on? Anesthetic agent in vaporizer? ---Oxygen flow rate adequate? ---Hoses attached ---Rebreathing bag attached Is the ET tube in the trachea? Is air leaking around the ET tube? Oxygen flow rate adequate? Is the animal apneic? Respirations too shallow? |
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What parameters should you use to judge when animals are anesthetized too deeply?
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Respiratory rate of 4 breaths/minute or fewer
Shallow breaths, dyspnea Pale or cyanotic MM CRT > 2 seconds Bradycardia Cardiac arrhythmias Cold extremities (body temperature <97F) Absent reflexes including corneal and/or anal Flaccid muscle tone Dilated pupils |
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What can cause the animal to be anesthetized too deeply?
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Vaporizer setting too high
Too high dose of injectable anesthetics Shock Anemia Other pre-existing conditions |
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What is a major cause of cardiac arrest in animals?
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Apnea
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What is temporary apnea?
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may or may not be a problem . Could be normal anesthetic depression
4 -6 breaths/minute are not uncommon |
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What is respiratory arrest?
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cessation of respiratory effort
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What does prolonged apnea cause?
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Low O2 levels (hypoxia)
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What does Low blood O2 levels cause?
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stress on cardiac muscles (since they cannot rest!)
Low O2 levels can also lead to CNS damage. |
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What does prolonged stress on the heart cause?
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Prolonged stress on the heart will cause it to beat progressively more weakly until the heart stops= Cardiac Arrest!
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How quickly should you act for CPR?
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2-3 minutes
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What stage/plane is a crisis?
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Stage III Plane IV
Stage IV |
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What should you monitor?
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Respiratory system, Cardiovascular system, Reflexes
If the patient is breathing with adequate depth (quality), things are usually OK Watch for Prolonged apnea! |
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How does animal age affect anesthetic?
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Age-young and old animals require less anesthetic.
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How do metabolic rates affect anesthesia?
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Lower metabolism = lower dose needed
Higher metabolism = higher dose needed |
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What are important considerations for anesthesia?
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Lung, liver and kidney function
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What happens to injectable anesthetics in the body?
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Injectable anesthetics are bio-transformed and/or metabolized then excreted from body.
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Does a small animal need a higher or lower dose? Why?
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Higher
Have higher body surface area when compared to that of larger animals May need a more anesthetic per pound than larger animals |
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Does an obese animal need a higher or lower dose? Why?
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Fat animals generally have lower metabolism
Will require less anesthetic than lean, muscular animals. |
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Does a sick animal need a higher or lower dose? Why?
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Sick animal require less
Illness usually lowers metabolic rate |
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What should you remember about anesthetic and metabolism?
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Remember, the lower the patient’s metabolism, the longer it takes for the anesthetic to be metabolized
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What about sitehounds and anesthetic?
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increased sensitivity to barbiturates. Lack of body fat for redistribution and inefficient hepatic metabolism.
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What are the General Principles of
Fluid Therapy?
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Replace Lost H2 O (Deficit)
Maintain Hydration (Daily Maintenance Needs) Correct Acid-base Abnormalities Supply Lost Electrolytes Correct Intravascular Osmotic Pressure Improve Renal Function Provide Caloric Intake |
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What are the Principals of Fluid Therapy
During Anesthesia?
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-Correction of normal ongoing fluid losses
Lungs, skin, respiratory tract, sweating -Counter any negative effects of anesthetic agents Hypotension (low blood pressure) Vasodilation -Support of the cardiovascular system Maintain an adequate and effective blood volume -Maintain cardiac output and tissue perfusion Blood loss during surgery -Maintain patency of an IV route |
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What is involved in patient assessment?
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Patient History
Physical Exam Findings Pre-Anesthetic Bloodwork Length & Type of Procedure |
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What are fluid types?
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Crystalloids
Colloids Whole Blood & Blood Products |
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What are crystalloid solutions?
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-Contain electrolytes and other substances capable of entering all fluid compartments. (Na, Cl, K, glucose, lactate).
-Additives used to correct abnormalities determined by lab findings. |
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What are examples of crystalloid solutions?
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Examples - 0.9% saline, LRS, Ringers
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What fluids do we use most commonly?
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Crystalloid fluids
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What is osmosis?
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-diffusion of water across a semi-permeable membrane from low solute to high solute.
-Cell walls & the endothelium are semi-permeable |
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What is a solute?
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-A solute is any substance dissolved in a solution
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What is diffusion?
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Molecules spread from an area of high concentration to an area of low concentration. No energy is required.
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What is active transport?
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Cells must move material in different directions against a concentration gradient. Energy is required.
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What does it mean if a crystalloid fluid is isotonic?
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equally osmolar as blood
~275-300 mOsmol/L |
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What does it mean if a crystalloid fluid is hypotonic?
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less osmolar than blood
Moves water into cells. Hydrate cells and deplete the circulatory system. Rarely used in veterinary medicine |
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What does it mean if a crystalloid fluid is hypertonic?
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more osmolar than blood
Moves water from the cell to the extra-cellular fluid. Used to replace electrolytes and increase blood volume. |
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What happens if a hypertonic fluid is injected perivascularly?
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A hypertonic solution is injected perivascularly extracellular fluid diffuses to the site of injection tissue swelling tissue necrosis and sloughing
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How do we determine osmolarity?
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Read the label!!! Like any medication, the contents are listed
Anything added to 0.9% NaCl, Normosol®, 5% Dextrose will be hypertonic. >300 mOsmole/L is hypertonic |
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What should we consider when reading the bag?
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Consider any additions to the bag-these will change the composition from that listed on bag
50% dextrose Mannitol |
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What osmolarity does normal saline have?
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Normal Saline: 0.9% NaCl
This is same physiologic osmolality as blood |
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What does normosol contain?
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Normosol® (saline, K+, Mg+)
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What does Lactated Ringers Solution (“LRS”) contain?
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Contains Na+, Cl-, Calcium chloride and lactate, which is converted in the liver to Na bicarbonate (a basic buffering agent to fight acidosis).
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What is Ringers Solution?
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Same as LRS w/o lactate
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What are two other examples of isotonic solutions?
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5% Dextrose in Water (D-5-W)
0.45% NaCl + 2.5% Dextrose |
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What are examples of hypotonic solutions?
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Sterile water for injection (0 mOsmole/L)
0.45% NaCl 2.5% dextrose in water |
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What are examples of hypertonic solutions?
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-50% Dextrose
-Mannitol -0.9% NaCl + 5% dextrose added in-house -LRS + 5% dextrose -0.45% NaCl + 5% dextrose -Plasma Expanders– Dextran, Hetastarch, 7% Saline. -Used in shock situations to rapidly expand blood volume – does so at the expense of extracellular fluids. -Animal will need additional fluids or become dehydrated. |
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What are colloid solutions used for?
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Are used as blood expanders – draw fluid into vascular system or hold fluid in vascular system
Used to treat shock |
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What are examples of colloid solutions?
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Hetastarch (starch) – holds fluid in vascular space
Dextrans (starch) – draws fluid from the interstitial to vascular Plasma – expands intravascular volume |
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How do colloid solutions work?
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Large molecules do not diffuse as readily through membranes therefore colloid fluids stay put and enhance the plasma volume better than crystalloids
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What is a Healthy Animal Fluid Rate During Surgery?
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Cats - 3 ml/kg/hr
Dogs – 5 ml/kg/hr |
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What is the Fluid Administration System?
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-Gravity Flow
Need to check more frequently -Fluid pumps |
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What are Administration Considerations for fluids?
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-Use aseptic technique- Most fluids contain no preservatives
-If giving large volume of fluids you do not want to give large amount of preservatives -Ensure lines are primed to prevent air embolism -Administer hyper or hypo-tonic fluids slowly -Monitor for hemolytic reactions -Warm fluids when practical prior to administration -Monitor for equipment failure during administration Especially if giving IV without pump |
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What does success in treatment depend heavily on?
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Success in treatment depends heavily on monitoring and nursing care!
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How do we know if there is under-administration of fluids?
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Persistent increased HR, poor pulse quality, hypotension
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How do we know if there is over administration of fluids?
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Increased RR and effort
Watery nasal discharge Chemosis (eyelid swelling) Pitting Edema Coughing Pulmonary crackles (occurs late) |
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What do we use blood pressure to estimate?
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Blood pressure is used to estimate tissue perfusion
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What is common during anesthesia?
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Hypotension during anesthesia is common
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How do we Respond to Hypotension During Anesthesia?
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1. 1st assess anesthetic depth
Excessive anesthetic depth is common cause of hypotension If too deep – decrease anesthetic depth 2. Give IV bolus of crystalloid at 3 – 10 ml/kg 3. Repeat once if needed 4. If slow to respond, consider IV colloid Hetastarch 5. If not response, consider medication Vasopressor |
