2. Patient Preparation

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  • These procedures must all be completed before anesthesia can be induced.
  • Good communication is the best way to show a client that you care.
  • The MPD is used to make patient care decisions and to uncover potential anesthetic risks.
  • Confirm the procedure before working up the other parts of the MPD.
  • Ruminants need less xylazine; cats need less lidocaine.
  • Sighthounds examples: greyhounds and salukis.
  • Neonate = <2 weeks old. Pediatric = 2-8 weeks old. Geriatric = >75% of expected life span.
  • Epinephrine and cyclohexamines, xylazine, barbiturates, and halothane can cause cardiac arrhythmias. Amitriptyline and clomipramine can cause cardiac arrhythmias. Chloramphenicol can cause decreased biotransformation of barbiturate anesthetics and lead to prolonged recovery. Amitraz and selegeline can increase the effects of morphine and other opioids. They can also lead to additive effects with anticholinergics or CNS depressants. Antihistamines can cause CNS and respiratory depression with opioids.
  • Preexisting disease may cause increased risk of anesthesia complications. Sick animals may also introduce pathogens into the hospital.
  • Fainting is also known as syncope. Fainting is associated with decreased blood pressure, hypoxemia, and cardiac disease. Seizures are associated with CNS disorder, toxin ingestion, or metabolic disease (hypoglycemia).
  • The PE and PA are interdependent techniques of equal value and importance.
  • Before any procedure, make sure you have the correct animal – animals can be in the wrong cage.
  • Horse heart girth is measured around the chest behind the point of the shoulder. Horse length is measured from the point of the shoulder to the point of the pelvis.
  • Thinness—increased short-acting barbiturate sensitivity and more prone to hypothermia. Obesity—compromised cardiovascular system, decreased functional lung volume, difficult venipuncture and auscultation. Dose obese animals at their lean body weight to prevent overdose.
  • Rule of thumb: 1 kg sudden body weight loss corresponds to 1 liter of fluid loss. See Table 2-1.
  • A B/A/R patient is bright, alert, and responsive—he is noticeably engaged and interested in his environment. A Q/A/R patient is quiet, alert, and responsive—he is not really engaged or interested in what is going on around him. See Table 2-2.
  • Methods to determine pain score are discussed in Chapter 7.
  • See Table 2-3 for normal body temperatures.
  • Gait is the manner in which the patient moves. Is it lame?
  • Run hands over the entire body surface. In each area examined look for and report any abnormalities including inflammation, odors, hemorrhage or bruising, discharge, swelling, or discoloration.
  • Pupil constriction is known as miosis. Pupil dilation is known as mydriasis. PLR may be decreased in excited animals or after administration of anesthetic agents, anticholinergic drugs, or opioids.
  • The veterinary anesthetist must be aware of normal heart rates and how the above conditions may affect them. Large animals: bpm for 30 seconds multiplied by 2. Small animals: bpm for 10 seconds multiplied by 6.
  • With SA, the heart rate increases with inspiration and decreases with expiration.
  • More than one skipped heartbeat in a row is abnormal and must be reported. A-V blocks are not associated with breathing rhythms. SA can sound like an A-V block to an inexperienced person. Watch the patient breathe while auscultating the heart.
  • Murmurs can be associated with leaking valves, stenotic valves, stenotic vessels, and abnormal communication between heart chambers.
  • Abnormalities in mucous membrane color or CRT must be considered possible anesthetic risks and should be corrected prior to anesthetic drug administration.
  • Large and small animals: bpm for 30 seconds multiplied by 2. Instead of counting the rate, panting dogs may be recorded as “panting” as long as the respiratory effort appears normal.
  • Dyspnea and cyanosis are considered medical emergencies that require immediate attention.
  • Normal lung sounds are very quiet. Any more obvious sounds may be associated with pulmonary disease or cardiac failure.
  • In small animals, a full urinary bladder or colon may be palpated. In cats, the kidneys may be palpated. A distended abdomen may indicate fluid accumulation, pregnancy, organ enlargement, or tumor.
  • Each hospital will set its own guidelines for the preanesthetic diagnostic workup. See Table 2-4 for sample recommendations.
  • A patient’s status may change following treatment. The classification is recorded in the patient’s record.
  • A standard protocol is usually established for all P1 and P2 patients. Derivations from the standard protocol are made for P3-P5 patients.
  • Acetpromazine is a preanesthetic that is also an antiemetic—it will prevent vomiting. Xylazine will induce vomiting so the stomach can be emptied.
  • IV catheters are not placed in every surgical patient; but if the anesthetist needs multiple accesses to a vein, a catheter is the best choice.
  • a, Catheter (20 to 24 gauge, ¾ to 1 ½ inches long for cats; 16 to 22 gauge, 1 to 2 inches long for dogs); b, two approximately 6-inch-long strips of 1-inch porous adhesive tape, one approximately 6-inch-long and one approximately 3-inch-long strip of ½-inch tape; c, clipper with #40 blade; d, 1:1 chlorhexidine surgical scrub/water-soaked cotton balls and alcohol-soaked cotton balls; e, ½-inch plastic strip with antiseptic ointment; f, T-port, cap, or administration set (both the catheter and T-port should be flushed with saline before catheterization).
  • Standard aseptic technique uses three chlorhexidine-soaked alcohol cotton balls followed by three alcohol-soaked cotton balls. Assistant is needed to hold off the vein. Apply tension in a ventral direction to tense the skin. Position the catheter with the needle fully inserted and with the bevel up.
  • Advance the catheter and needle assembly as a unit through the skin and the near wall of the vein. Blood will flashback into the needle hub when the vein is entered. Advance the unit a few more millimeters until the end of the catheter is firmly seated in the vein. Holding the needle stationary, advance the catheter over the end of the needle until it is inserted to the hub. Remove the needle. Have the assistant apply pressure at the insertion site to prevent bleeding.
  • Flush the catheter with several milliliters of normal saline through the injection port. Twist the 3-inch-long strip of ½-inch tape into a “bow-tie” configuration.
  • Chlorhexidine ointment is used on the plastic strip.
  • Tear a ½-inch “V” in a 6-inch length of 1-inch tape about 1 inch from the end. Slip it under the catheter with the torn area directly under the catheter hub. Apply the remainder of this length of tape over the plastic strip to secure.
  • Apply the remaining 6-inch-long strip of 1-inch tape around the administration set line or T-port to create a tension loop.
  • IV fluids should be flowing at the standard infusion rate.
  • Pinching off the administration set line between the injection port and the fluid bag will prevent backflow of agent into the fluid bag during injection.
  • Give the medication at an appropriate rate as dictated by the VIC. For most medications, a slow IV bolus is appropriate. When inducing general anesthesia, inject an appropriate initial volume following the guidelines in Chapters 8, 9, and 10.
  • Following injection, the administration set line must be released so that the entire dose of medication is flushed into the patient. As much as 0.5 to 2 mL of agent will remain in the fluid line and catheter until flushed out. When administering an induction agent, administer additional doses to effect by following these same steps. As soon as the patient is at an anesthetic depth adequate to permit intubation, remove the needle and syringe to prevent accidental overdose.
  • Homeostasis is the state of health.
  • A basic understanding of the principles will help the anesthetist understand and administer proper fluid therapy.
  • The hypertonicity results in fluid being drawn into the intravascular space to maintain blood pressure.
  • Dextrose solutions are considered hypotonic solutions.
  • Colloid solutions stay in the intravascular space longer because of the large solutes that cannot pass through the endothelium.
  • Examples are LR, NR, and PL.
  • These rates are high to compensate for vasodilation, decreased cardiac output, and increased insensible fluid loss during surgery. See Table 2-9.
  • Hetastarch can cause nausea and vomiting if administered too rapidly.
  • Avoid overhydration with the use of a fluid pump or careful monitoring.
  • See Box 2-2.
  • 2. Patient Preparation

    1. 1. Patient Preparation All successful anesthetic procedures begin with careful patient preparation. Chapter 2
    2. 2. Role of the Veterinary Anesthetist <ul><li>Minimum patient database </li></ul><ul><li>Proper patient fasting </li></ul><ul><li>Preinduction patient care </li></ul><ul><li>All supplies are available </li></ul><ul><li>All equipment is in working order </li></ul><ul><li>Preanesthetic medication </li></ul>
    3. 3. Communication is Important <ul><li>Makes clients feel more comfortable and less anxious </li></ul><ul><li>Clients are more confident in your work </li></ul><ul><li>Good communication shows you care </li></ul><ul><li>An informed client can better handle unexpected results </li></ul>
    4. 4. Clients don’t care how much you know, until they know how much you care.
    5. 5. Minimum Patient Database (MPD) <ul><li>Patient history </li></ul><ul><li>Physical examination and assessment </li></ul><ul><li>Preanesthetic diagnostic workup </li></ul>
    6. 6. Confirm the Scheduled Procedure <ul><li>Verbally </li></ul><ul><li>Prevents tragic accidents </li></ul><ul><ul><li>Anesthetizing the wrong patient </li></ul></ul><ul><ul><li>Performing an unnecessary procedure </li></ul></ul><ul><ul><li>Not performing a scheduled procedure </li></ul></ul>
    7. 7. Confirm the Scheduled Procedure (Cont’d) <ul><li>Know the specifics </li></ul><ul><ul><li>Exact location of tumors </li></ul></ul><ul><ul><li>Exact location </li></ul></ul><ul><ul><li>Owner’s wishes regarding cytology or histology </li></ul></ul><ul><ul><li>Owner’s wishes regarding decisions during the procedure </li></ul></ul>
    8. 8. Patient History <ul><li>Information obtained from the client </li></ul><ul><li>Know what questions to ask and how to ask them </li></ul><ul><ul><li>Yes-no questions </li></ul></ul><ul><ul><li>Leading questions </li></ul></ul>
    9. 9. Patient History (Cont’d) <ul><li>In addition to information given freely, determine the following: </li></ul><ul><ul><li>Information given freely </li></ul></ul><ul><ul><li>Duration </li></ul></ul><ul><ul><li>Severity or volume </li></ul></ul><ul><ul><li>Frequency </li></ul></ul><ul><ul><li>Appearance or character </li></ul></ul>
    10. 10. Patient History—Signalment <ul><li>Species </li></ul><ul><ul><li>Species have unique responses to anesthetic agents </li></ul></ul><ul><ul><li>Horses and cats—opioids </li></ul></ul><ul><ul><li>Dosing requirements </li></ul></ul><ul><ul><li>Recovery—horses </li></ul></ul><ul><ul><li>Anticholinergics avoided in ruminants </li></ul></ul><ul><ul><li>Ventilation support—large animals </li></ul></ul><ul><ul><li>Excess airway secretions—cats and ruminants </li></ul></ul><ul><ul><li>Exotic animals are handled differently </li></ul></ul>
    11. 11. Patient History—Signalment (Cont’d) <ul><li>Breed </li></ul><ul><ul><li>Differences in anatomy and physiology </li></ul></ul><ul><ul><li>Sighthounds—sensitive to barbiturates </li></ul></ul><ul><ul><li>Boxers and giant breeds—sensitive to acepromazine </li></ul></ul><ul><ul><li>Terriers—resistant to acepromazine </li></ul></ul><ul><ul><li>Brachiocephalic dogs—difficult to intubate </li></ul></ul><ul><ul><li>Draft horses—sensitive to sedatives </li></ul></ul>
    12. 12. Patient History—Signalment (Cont’d) <ul><li>Age </li></ul><ul><ul><li>Plays a factor in drug choice </li></ul></ul><ul><ul><ul><li>Neonates and pediatric patients </li></ul></ul></ul><ul><ul><ul><li>Geriatric patients </li></ul></ul></ul>
    13. 13. Patient History—Signalment (Cont’d) <ul><li>Sex and reproductive status </li></ul><ul><ul><li>Male or female </li></ul></ul><ul><ul><li>Intact or neutered </li></ul></ul><ul><ul><li>Used for breeding? </li></ul></ul><ul><ul><li>Pregnant </li></ul></ul><ul><ul><li>Stallions—acepromazine </li></ul></ul><ul><ul><li>Pregnant cows and ewes—xylazine </li></ul></ul>
    14. 14. Patient History—Medications <ul><li>Current or past </li></ul><ul><li>May influence effect of anesthetic agents </li></ul><ul><li>Sympathomimetics </li></ul><ul><li>Tricyclic antidepressants </li></ul><ul><li>Antibiotics </li></ul><ul><li>Monoamine oxidase inhibitors </li></ul><ul><li>Antihistamines </li></ul>
    15. 15. Patient History—Allergies/Drug Reactions <ul><li>Record in the history to prevent future administration </li></ul><ul><li>Past adverse reactions to anesthetic agents </li></ul><ul><ul><li>Cats—prolonged ketamine recovery </li></ul></ul><ul><ul><li>Dogs—behavioral change after acepromazine sedation </li></ul></ul>
    16. 16. Patient History—Preventive Care <ul><li>Vaccination—date and type </li></ul><ul><li>Fecal analysis and parasite control </li></ul><ul><li>Heartworm status—dogs </li></ul><ul><li>FLV and FIV testing—cats </li></ul><ul><li>Tetanus toxoid—horses </li></ul>
    17. 17. Patient History—Past/Current Illnesses <ul><li>Preexisting disease </li></ul><ul><li>Anorexia, vomiting, diarrhea, coughing, sneezing, polyuria, polydipsia, tenesmus, dysuria </li></ul><ul><ul><li>General signs of illness </li></ul></ul><ul><ul><li>Stabilized prior to anesthesia </li></ul></ul><ul><li>Change in behavior </li></ul><ul><ul><li>CNS disorder </li></ul></ul><ul><ul><li>Pain </li></ul></ul><ul><ul><li>Systemic illness </li></ul></ul>
    18. 18. Patient History—Past/Current Illnesses (Cont’d) <ul><li>Exercise intolerance </li></ul><ul><ul><li>Heart disease </li></ul></ul><ul><ul><li>Anemia </li></ul></ul><ul><ul><li>Musculoskeletal pain </li></ul></ul><ul><li>Weakness </li></ul><ul><ul><li>A nonspecific sign </li></ul></ul><ul><li>Fainting or seizures </li></ul><ul><ul><li>Often difficult to differentiate </li></ul></ul><ul><ul><li>Have different etiologies </li></ul></ul>
    19. 19. Past History—Past/Current Illnesses <ul><li>Unexplained bleeding </li></ul><ul><ul><li>Bruising </li></ul></ul><ul><ul><li>Blood in feces or urine </li></ul></ul><ul><ul><li>Prolonged bleeding after injury </li></ul></ul><ul><li>Associated with coagulation disorders </li></ul><ul><li>Increased risk of intra- and postoperative hemorrhage </li></ul>
    20. 20. Other Considerations <ul><li>Written estimate </li></ul><ul><li>Signed consent form </li></ul><ul><ul><li>Legally necessary </li></ul></ul><ul><ul><li>Informs of risks </li></ul></ul><ul><ul><li>Standard forms are available </li></ul></ul><ul><ul><li>Owner’s daytime phone number </li></ul></ul><ul><ul><li>Permission to perform CPCR </li></ul></ul><ul><ul><li>Lists extralabel drugs used </li></ul></ul>
    21. 21. Physical Examination (PE) vs. Physical Assessment (PA) <ul><li>PE </li></ul><ul><ul><li>Performed by a veterinarian </li></ul></ul><ul><ul><li>To determine diagnosis and treatment planning </li></ul></ul><ul><li>PA </li></ul><ul><ul><li>Performed by a veterinary technician </li></ul></ul><ul><ul><li>To provide patient care, respond to patient needs, detect changes in patient condition </li></ul></ul><ul><li>PE and PA </li></ul><ul><ul><li>Both necessary and important to ensure high quality of patient care </li></ul></ul>
    22. 22. Physical Examination/Physical Assessment <ul><li>Examine the entire patient </li></ul><ul><li>Use a consistent technique </li></ul><ul><ul><li>Head to tail </li></ul></ul><ul><ul><li>Organ system </li></ul></ul><ul><li>Cardiovascular, nervous, and pulmonary systems are most affected by anesthetic agents </li></ul>
    23. 23. Patient Identification <ul><li>Cage tags </li></ul><ul><li>Patient identification collars </li></ul><ul><li>Document external characteristics in medical record </li></ul><ul><ul><li>Species and breed </li></ul></ul><ul><ul><li>Size </li></ul></ul><ul><ul><li>Hair coat length </li></ul></ul><ul><ul><li>Color </li></ul></ul>
    24. 24. Body Weight <ul><li>Must be accurate for proper dosing </li></ul><ul><ul><li><5 kg use a pediatric scale </li></ul></ul><ul><ul><li><1 kg use a gram scale </li></ul></ul><ul><ul><li>Horses—estimated weight </li></ul></ul><ul><ul><li>body weight (kg) = heart girth (cm) 2 × length (cm) </li></ul></ul><ul><ul><li>11880 </li></ul></ul><ul><ul><li>Weigh animals immediately before anesthetic procedure </li></ul></ul><ul><ul><li>Compare current weight with previously recorded weight </li></ul></ul>
    25. 25. Body Condition Score <ul><li>Assessment of patient weight to the ideal weight </li></ul><ul><li>A numeric assessment </li></ul><ul><ul><li>1-9 scale </li></ul></ul><ul><ul><ul><li>4-5 in dogs or 5 in cats is the ideal weight </li></ul></ul></ul><ul><ul><ul><li>1 is extreme cachexia; 9 is extreme obesity </li></ul></ul></ul><ul><ul><li>1-5 scale </li></ul></ul><ul><ul><ul><li>3 is the ideal weight </li></ul></ul></ul><ul><ul><ul><li>1 is extreme cachexia; 5 is extreme obesity </li></ul></ul></ul><ul><li>Body condition influences patient management </li></ul>
    26. 26. Hydration Assessment <ul><li>Skin turgor </li></ul><ul><li>Placement of eye in orbit </li></ul><ul><li>Mucous membrane color, refill time, moisture level </li></ul><ul><li>Heart rate and pulse strength </li></ul><ul><li>Correct hydration abnormalities prior to anesthesia </li></ul><ul><li>Young and obese patients appear more hydrated </li></ul><ul><li>Old and cachectic patients appear less hydrated </li></ul><ul><li>Panting dries the mucous membranes </li></ul>
    27. 27. Level of Consciousness (LOC) <ul><li>To assess brain function </li></ul><ul><li>Patient’s responsiveness to stimuli </li></ul><ul><li>Healthy patients: alert, responsive, bright or quiet </li></ul><ul><li>Lethargic (lethargy) </li></ul><ul><li>Obtunded (obtundity) </li></ul><ul><li>Stuporous (stupor) </li></ul><ul><li>Comatose (coma) </li></ul>
    28. 28. Pain Score <ul><li>Assess patient’s level of pain </li></ul><ul><li>To help select preanesthetic and anesthetic agents </li></ul>
    29. 29. Body Temperature <ul><li>Use a rectal thermometer </li></ul><ul><li>Elevated = inflammation </li></ul><ul><li>Decreased = numerous systemic disorders </li></ul>
    30. 30. General Condition <ul><li>Visual examination from a distance </li></ul><ul><li>Gait </li></ul><ul><li>Temperament </li></ul><ul><ul><li>Anxious or excited? Or ill? </li></ul></ul><ul><li>Activity level </li></ul><ul><ul><li>Exercise intolerance </li></ul></ul><ul><ul><li>Weakness </li></ul></ul><ul><li>Will affect choice of anesthetic agents and methods of administration </li></ul>
    31. 31. Exterior Surfaces <ul><li>Hair coat </li></ul><ul><li>Skin </li></ul><ul><ul><li>Part the hair and look at the skin </li></ul></ul><ul><li>Lymph nodes and mammary glands </li></ul><ul><ul><li>Visual and manual examination </li></ul></ul><ul><li>Body openings </li></ul><ul><ul><li>Odors and discharges </li></ul></ul><ul><li>Eyes, ears, nose, oral cavity (throat) </li></ul><ul><ul><li>EENT </li></ul></ul>
    32. 32. Pupillary Light Reflex (PLR) <ul><li>Normal—pupils are the same size </li></ul><ul><li>Direct reflex </li></ul><ul><li>Consensual reflex </li></ul>
    33. 33. Cardiovascular System Examination—Heart Rate <ul><li>Measured as beats per minute (bpm) </li></ul><ul><li>Auscultation of left chest wall </li></ul><ul><li>Large animal patients vs. small animal patients </li></ul><ul><li>Obese animals, panting dogs, purring cats </li></ul><ul><li>Pediatric patients </li></ul><ul><li>Exercise or stress of handling </li></ul>
    34. 34. Cardiovascular System Examination—Heart Rhythm <ul><li>Evaluation of the heart rate </li></ul><ul><li>Normal sinus rhythm (NSR) </li></ul><ul><ul><li>Dogs, cats, rodents, ferrets, rabbits, horses, ruminants </li></ul></ul><ul><ul><li>No rhythm irregularities </li></ul></ul><ul><li>Sinus arrhythmia (SA) </li></ul><ul><ul><li>Dogs, horses, ruminants </li></ul></ul><ul><ul><li>Heart rate is affected by respiration </li></ul></ul>
    35. 35. Cardiovascular System Examination—Heart Rhythm (Cont’d) <ul><li>First degree atrioventricular (A-V) heart block </li></ul><ul><ul><li>Delayed conduction through the A-V node </li></ul></ul><ul><ul><li>Detected only on ECG tracing </li></ul></ul><ul><li>Second degree A-V heart block </li></ul><ul><ul><li>Periodic block of conduction through the A-V node </li></ul></ul><ul><ul><li>Results in skipped heartbeats </li></ul></ul>
    36. 36. Cardiovascular System Examination—Murmurs <ul><li>Listen over each valve </li></ul><ul><ul><li>Cranial-most aspect of left axilla—PDA </li></ul></ul><ul><li>Caused by blood flow turbulence </li></ul><ul><li>May result in increased patient anesthetic risk </li></ul>
    37. 37. Cardiovascular System Examination—Pulse <ul><li>Pulse palpation points </li></ul><ul><ul><li>Dogs and cats—femoral artery </li></ul></ul><ul><ul><li>Large animals—facial artery, ventral tail artery, or auricular artery </li></ul></ul><ul><li>Pulse deficit </li></ul><ul><li>Blood pressure estimate </li></ul>
    38. 38. Cardiovascular System Examination—Mucous Membrane Color <ul><li>Mucous membrane color </li></ul><ul><ul><li>Gingiva at base of tooth </li></ul></ul><ul><ul><li>Alternate sites </li></ul></ul><ul><ul><li>Pale or cyanotic membranes </li></ul></ul><ul><li>Capillary refill time (CRT) </li></ul><ul><ul><li>Normal = <2 seconds </li></ul></ul><ul><ul><li>Prolonged refill time </li></ul></ul>
    39. 39. Respiratory System Examination—Breath Rate <ul><li>Measured in breaths per minute (bpm) </li></ul><ul><li>Evaluated visually </li></ul><ul><li>Inversely proportional to body size </li></ul>
    40. 40. Respiratory System Examination—Breathing Character <ul><li>Effort </li></ul><ul><ul><li>Dyspnea and cyanosis </li></ul></ul><ul><li>Relative length of inhalation and exhalation </li></ul><ul><li>Regularity of inhalation and exhalation </li></ul><ul><li>Inhale – exhale – rest – inhale –exhale –rest </li></ul>
    41. 41. Respiratory System Examination—Lung Auscultation <ul><li>Four quadrants </li></ul><ul><li>Discontinuous sounds </li></ul><ul><li>Continuous sounds </li></ul>
    42. 42. Abdominal Palpation and Auscultation <ul><li>Normal is soft and not painful </li></ul><ul><li>Firm or painful structures </li></ul><ul><li>Abdominal distention </li></ul><ul><li>Borborygmus—large animals </li></ul><ul><li>Rumen contraction—ruminants </li></ul>
    43. 43. Preanesthetic Diagnostic Workup <ul><li>No one standardized diagnostic workup fits every patient to be anesthetized </li></ul><ul><ul><li>Geriatric patient workup </li></ul></ul><ul><ul><li>Elective surgery patient workup </li></ul></ul><ul><ul><li>Sick patient workup </li></ul></ul><ul><ul><li>Workup based on age, history, and physical examination </li></ul></ul><ul><ul><li>Workup based on financial considerations </li></ul></ul><ul><li>Completed after the patient history has been taken and the physical examination has been performed </li></ul>
    44. 44. Preanesthetic Diagnostic Tests and Procedures <ul><li>Complete blood count (CBC) </li></ul><ul><li>Urinalysis </li></ul><ul><li>Blood chemistry </li></ul><ul><li>Blood coagulation screens </li></ul><ul><li>Electrocardiogram (ECG) </li></ul><ul><li>Radiography </li></ul><ul><li>Other tests as deemed necessary </li></ul>
    45. 45. Physical Status Classification <ul><li>Classification is based on an evaluation of the Minimum Patient Database </li></ul><ul><li>Rates patient anesthetic risk </li></ul><ul><ul><li>American Society of Anesthesiologists </li></ul></ul><ul><ul><li>Class P1 = minimal anesthetic risk </li></ul></ul><ul><ul><li>Class P5 = extreme anesthetic risk </li></ul></ul><ul><ul><li>Classes P1 and P2 use standard anesthetic protocol </li></ul></ul><ul><ul><li>Classes P3 to P5 need special protocols and stabilization </li></ul></ul>
    46. 46. Anesthetic Protocols <ul><li>Established by the veterinarian </li></ul><ul><li>Factors considered </li></ul><ul><ul><li>Facilities and equipment </li></ul></ul><ul><ul><li>Familiarity with anesthetic agents </li></ul></ul><ul><ul><li>Nature of the procedure </li></ul></ul><ul><ul><li>Circumstances specific to a procedure </li></ul></ul><ul><ul><li>Cost </li></ul></ul><ul><ul><li>Urgency </li></ul></ul>
    47. 47. Preinduction Patient Care <ul><li>Withholding food </li></ul><ul><ul><li>Complications </li></ul></ul><ul><ul><ul><li>Esophageal reflux, vomiting, regurgitation, pulmonary aspiration, pneumonia </li></ul></ul></ul><ul><ul><li>if the patient is not fasted, one of several actions must be taken. </li></ul></ul><ul><ul><li>Preanesthetic with antiemetic properties </li></ul></ul><ul><li>Patient stabilization </li></ul><ul><ul><li>Sick patients </li></ul></ul><ul><ul><li>Patients with concurrent conditions </li></ul></ul><ul><ul><li>Reduces anesthetic risk </li></ul></ul>
    48. 48. Intravenous (IV) Catheterization <ul><li>Reasons for placing an IV catheter </li></ul><ul><ul><li>Fluid administration </li></ul></ul><ul><ul><li>Rapid IV access in an emergency </li></ul></ul><ul><ul><li>Constant rate infusion (CRI) of drugs or anesthetic agents </li></ul></ul><ul><ul><li>Administration of vesicants </li></ul></ul><ul><ul><li>Sequential administration of incompatible drugs </li></ul></ul>
    49. 49. Intravenous Catheters <ul><li>Through-the-needle </li></ul><ul><li>Over-the-needle </li></ul><ul><ul><li>Most commonly used </li></ul></ul><ul><ul><li>16-24 gauge, 3/4 - to 2-inch catheter (small animals) </li></ul></ul><ul><ul><li>12-16 gauge, 5¼-inch catheter (large animals) </li></ul></ul>
    50. 50. IV Catheter Placement and Maintenance <ul><li>Length </li></ul><ul><li>Size </li></ul><ul><li>Location </li></ul><ul><li>Administration set with injection port </li></ul><ul><li>Free-flowing fluids </li></ul><ul><li>Minimal patient and catheter movement </li></ul><ul><li>Slow administration </li></ul><ul><li>Saline flush </li></ul>
    51. 51. Placing an IV Catheter in a Small Animal Patient <ul><li>Equipment </li></ul>
    52. 52. Placing an IV Catheter in a Small Animal Patient (Cont’d) <ul><li>Clip area over the vein </li></ul><ul><li>Prepare the area using an aseptic technique </li></ul><ul><li>Place tape over the catheter hub </li></ul><ul><li>Hold off the vein, tense the skin, and position the catheter </li></ul>
    53. 53. Placing an IV Catheter in a Small Animal Patient (Cont’d) <ul><li>Advance the catheter </li></ul><ul><li>assembly through the skin </li></ul><ul><li>Advance it further to firmly </li></ul><ul><li>seat in the vein </li></ul><ul><li>Advance the catheter over the end of the needle </li></ul><ul><li>Remove the needle </li></ul><ul><li>Apply pressure </li></ul>
    54. 54. Placing an IV Catheter in a Small Animal <ul><li>Attach T-port, cap, or set line to the catheter hub </li></ul><ul><li>Secure the catheter with </li></ul><ul><li>tape </li></ul><ul><li>Flush the catheter with </li></ul><ul><li>saline </li></ul><ul><li>Twist the tape into a “bow-tie” </li></ul>
    55. 55. Placing an IV Catheter in a Small Animal (Cont’d) <ul><li>Crisscross the tape under and around the catheter hub </li></ul><ul><li>Apply ointment to plastic strip </li></ul>
    56. 56. Placing an IV Catheter in a Small Animal (Cont’d) <ul><li>Apply the plastic strip over the site of insertion </li></ul><ul><li>Secure the catheter with tape </li></ul>
    57. 57. Placing an IV Catheter in a Small Animal (Cont’d) <ul><li>Create a tension loop with tape </li></ul>
    58. 58. Giving an IV Injection Through an IV Administration Set Port <ul><li>Prepare medication or induction agent </li></ul><ul><li>Cleanse injection port with alcohol </li></ul>
    59. 59. Giving an IV Injection Through an IV Administration Set Port (Cont’d) <ul><li>Insert the needle in the injection port </li></ul><ul><li>Pinch off the administration set line </li></ul>
    60. 60. Giving an IV Injection Through an IV Administration Set Port (Cont’d) <ul><li>Give medication at an appropriate rate </li></ul>
    61. 61. Giving an IV Injection Through an IV Administration Set Port (Cont’d) <ul><li>Release administration set line </li></ul>
    62. 62. Fluid Administration
    63. 63. Composition of Body Fluids <ul><li>Water </li></ul><ul><ul><li>Intracellular (ICF) </li></ul></ul><ul><ul><li>Extracellular (ECF) </li></ul></ul><ul><ul><ul><li>Vascular </li></ul></ul></ul><ul><ul><ul><li>Interstitial </li></ul></ul></ul><ul><li>Other elements (solutes) </li></ul>
    64. 64. Blood Volume <ul><li>Plasma is 5% of body weight </li></ul><ul><li>Blood volume </li></ul><ul><ul><li>8-9% of body weight—dogs and large animals </li></ul></ul><ul><ul><li>6-7% of body weight—cats </li></ul></ul><ul><li>Calculating blood volume </li></ul><ul><ul><li>Dogs and large animals = 90 mL/kg lean body weight </li></ul></ul><ul><ul><li>Cats = 60 mL/kg lean body weight </li></ul></ul>
    65. 65. Solutes <ul><li>Ions—small molecular weight and electrically charged </li></ul><ul><ul><li>Electrolytes </li></ul></ul><ul><ul><ul><li>Cations—positive charge </li></ul></ul></ul><ul><ul><ul><li>Anions—negative charge </li></ul></ul></ul><ul><li>colloids—large molecular weight plasma proteins </li></ul><ul><li>Small nonionic particles </li></ul>
    66. 66. Important Electrolytes <ul><li>Cations </li></ul><ul><ul><li>Sodium (Na + ) </li></ul></ul><ul><ul><li>Potassium (K + ) </li></ul></ul><ul><ul><li>Magnesium (Mg 2+ ) </li></ul></ul><ul><ul><li>Calcium (Ca 2+ ) </li></ul></ul><ul><li>Anions </li></ul><ul><ul><li>Chloride (Cl − ) </li></ul></ul><ul><ul><li>Bicarbonate (HCO 3 − ) </li></ul></ul><ul><ul><li>Phosphates (HPO 4 2 − and H 2 PO 4 − ) </li></ul></ul><ul><ul><li>Proteins </li></ul></ul>
    67. 67. Homeostasis <ul><li>A constant state within the body created and maintained by normal physiologic processes </li></ul><ul><li>Water and solute movement </li></ul><ul><ul><li>Passive diffusion </li></ul></ul><ul><ul><li>Active transport </li></ul></ul><ul><li>Composition of fluid compartments varies normally </li></ul><ul><ul><li>ICF: K + , Mg 2+ , protein, and phosphate </li></ul></ul><ul><ul><li>ECF: Na + , Cl − , HCO 3 − </li></ul></ul>
    68. 68. Principles of Water and Solute Balance <ul><li>In any given compartment, positively and negatively charged particle numbers must be equal. </li></ul><ul><li>Solute concentration (osmolarity) in any fluid compartment must be 300 mOms/L. </li></ul><ul><li>Solutes must provide osmotic pressure to pull water into a compartment. </li></ul><ul><li>Small solutes (ions) pass freely into and out of the intravascular space from the interstitial space. Water follows to create equilibrium. </li></ul>
    69. 69. Principles of Water and Solute Balance (Cont’d) <ul><li>One-third of IV fluids administered will stay in the intravascular space. Two-thirds will diffuse into the interstitial space. </li></ul><ul><ul><li>Colloids don’t pass freely through the vascular endothelium. </li></ul></ul><ul><ul><li>The presence of colloids in the intravascular space draws water into the space creating osmotic or oncotic pressure. </li></ul></ul><ul><ul><li>Some solute concentrations (Ca 2+ , K + ) must be kept within a narrow range to maintain normal heart and muscle function. </li></ul></ul>
    70. 70. Fluid Loss and General Anesthesia <ul><li>Dehydration, anorexia, general disease condition </li></ul><ul><ul><li>Depletes ECF </li></ul></ul><ul><ul><li>Administer fluids with a solute profile similar to ECF </li></ul></ul><ul><li>Perioperative hemorrhage </li></ul><ul><ul><li>Loss from intravascular space </li></ul></ul><ul><ul><li>Administer fluids with a solute profile similar to ECF </li></ul></ul><ul><ul><li>Administer hypertonic saline or colloid solutions </li></ul></ul>
    71. 71. Fluid Loss and General Anesthesia (Cont’d) <ul><li>Significant perioperative hemorrhage </li></ul><ul><ul><li>Loss of blood constituents, water, electrolytes </li></ul></ul><ul><ul><li>Administer blood products </li></ul></ul><ul><li>Low albumin </li></ul><ul><ul><li>Administer blood plasma or colloid solutions </li></ul></ul>
    72. 72. Intravenous Fluids <ul><li>Composition varies </li></ul><ul><ul><li>One or more electrolytes </li></ul></ul><ul><ul><li>Dextrose </li></ul></ul><ul><ul><li>Buffers </li></ul></ul><ul><ul><li>Colloids </li></ul></ul><ul><li>Classification </li></ul><ul><ul><li>Crystalloid </li></ul></ul><ul><ul><li>Colloid </li></ul></ul>
    73. 73. Crystalloid Intravenous Fluids <ul><li>Water and small-molecular-weight solutes </li></ul><ul><li>May contain dextrose and/or buffers </li></ul><ul><li>Often used in anesthetized patients </li></ul>
    74. 74. Crystalloid Intravenous Fluids (Cont’d) <ul><li>Isotonic, polyionic replacement solutions </li></ul><ul><ul><li>Similar to ECF </li></ul></ul><ul><ul><li>Lactated Ringer’s solution (LR) </li></ul></ul><ul><ul><li>Normosol-R (NR) </li></ul></ul><ul><ul><li>Plasma-Lyte A and R (PA and PR) </li></ul></ul><ul><ul><li>Isolyte S (IS) </li></ul></ul><ul><ul><li>LR and PR contain calcium and cannot be administered with blood products </li></ul></ul>
    75. 75. Crystalloid Intravenous Fluids (Cont’d) <ul><li>Isotonic, polyionic maintenance solutions </li></ul><ul><ul><li>For use over a longer time </li></ul></ul><ul><ul><li>Contain less sodium and chloride </li></ul></ul><ul><ul><li>Contain more potassium </li></ul></ul><ul><ul><li>Contain lower concentrations of buffer </li></ul></ul><ul><ul><li>Contain dextrose </li></ul></ul><ul><ul><li>Normosol-M in 5% dextrose (NM5) </li></ul></ul><ul><ul><li>Plasma-Lyte 56 in 5% dextrose (PL5) </li></ul></ul>
    76. 76. Crystalloid Intravenous Fluids (Cont’d) <ul><li>Normal saline (NS) </li></ul><ul><ul><li>Physiologic saline, 0.9% saline, or sodium chloride 0.9% </li></ul></ul><ul><ul><li>Contains only sodium and chloride dissolved in water </li></ul></ul><ul><ul><li>Sometimes used instead of isotonic, polyionic replacement crystalloid solution </li></ul></ul><ul><ul><li>Used to bathe tissues during surgery </li></ul></ul><ul><ul><li>Used to flush the IV catheter </li></ul></ul><ul><ul><li>Used to flush body cavities </li></ul></ul>
    77. 77. Crystalloid Intravenous Fluids (Cont’d) <ul><li>Hypertonic saline solutions </li></ul><ul><ul><li>3%, 5%, 7%, or 23.4% solutions </li></ul></ul><ul><ul><li>Administered with isotonic crystalloid fluids </li></ul></ul><ul><ul><li>Used to treat acute shock </li></ul></ul>
    78. 78. Crystalloid Intravenous Fluids (Cont’d) <ul><li>Dextrose solutions </li></ul><ul><ul><li>5% dextrose in water (D 5 W) or 2.5% dextrose </li></ul></ul><ul><ul><li>May be found in some maintenance polyionic solutions </li></ul></ul><ul><ul><li>Used to support blood sugar levels </li></ul></ul><ul><ul><li>D 5 W is used to replace fluid loss due to dehydration or heat stroke </li></ul></ul>
    79. 79. Colloid Solutions <ul><li>Contain large-molecular-weight solutes </li></ul><ul><li>Used to support blood volumes and blood pressure </li></ul><ul><li>Synthetic colloid solutions </li></ul><ul><ul><li>Hetastarch </li></ul></ul><ul><ul><li>Stay primarily in intravascular space </li></ul></ul><ul><li>Blood products </li></ul><ul><ul><li>Plasma and whole blood </li></ul></ul><ul><li>Hemoglobin-based oxygen carriers </li></ul><ul><ul><li>Human or bovine hemoglobin </li></ul></ul><ul><ul><li>No need for crossmatch </li></ul></ul>
    80. 80. Fluid Selection <ul><li>Healthy animal undergoing routine surgery </li></ul><ul><ul><li>Isotonic, polyionic, replacement fluids </li></ul></ul><ul><li>Sick patients </li></ul><ul><ul><li>PCV =>20, TP =>3.5 g/dL </li></ul></ul><ul><ul><li>Isotonic, polyionic replacement fluids </li></ul></ul>
    81. 81. Administration Rate <ul><li>During routine anesthesia and surgery </li></ul><ul><ul><li>10 mL/kg/hr during the first hour </li></ul></ul><ul><ul><li>5 mL/kg/hr during remainder of the procedure </li></ul></ul>
    82. 82. Fluid Administration Rate—Isotonic Crystalloids <ul><li>Excessive hemorrhage or hypotension </li></ul><ul><ul><li>40 mL/kg/hr (dogs and large animals) </li></ul></ul><ul><ul><li>20 mL/kg/hr (cats) </li></ul></ul><ul><li>Shock </li></ul><ul><ul><li>90 mL/kg/hr as rapidly as possibly (dogs and large animals) </li></ul></ul><ul><ul><li>55 mL/kg/hr as rapidly as possible (cats) </li></ul></ul><ul><li>Shock and blood loss (large and small animals) </li></ul><ul><ul><li>7% hypertonic saline </li></ul></ul><ul><ul><li>3-4 mL/kg slowly over 5 minutes </li></ul></ul><ul><ul><li>Followed by isotonic crystalloid solution </li></ul></ul>
    83. 83. Fluid Administration Rate—Colloids <ul><li>10-20 mL/kg/day (dogs and large animals) </li></ul><ul><li>5-10 mL/kg/day (cats) </li></ul><ul><ul><li>Monitor to prevent overload, coagulation disorders, and allergies </li></ul></ul><ul><li>Administer as a slow bolus </li></ul><ul><ul><li>Over 15-60 minutes (dogs and large animals) </li></ul></ul><ul><ul><li>Over 30-60 minutes (cats) </li></ul></ul>
    84. 84. Adverse Effects of Fluid Administration <ul><li>Volume overload </li></ul><ul><ul><li>Pulmonary or cerebral edema </li></ul></ul><ul><ul><li>Use slower infusion rate </li></ul></ul><ul><li>Overhydration </li></ul><ul><ul><li>Ocular and nasal discharge </li></ul></ul><ul><ul><li>Chemosis </li></ul></ul><ul><ul><li>Subcutaneous edema </li></ul></ul><ul><ul><li>Increased lung sounds </li></ul></ul><ul><ul><li>Increased respiratory rate and dyspnea </li></ul></ul><ul><ul><li>Coughing and restlessness if patient is awake </li></ul></ul><ul><ul><li>Hemodilution </li></ul></ul>
    85. 85. Fluid Administration <ul><li>Infusion pump </li></ul><ul><li>Tape scale to monitor rate </li></ul>
    86. 86. Fluid Administrations (Cont’d) <ul><li>Burette for small-volume use </li></ul>
    87. 87. Definitions <ul><li>Prescribed rate </li></ul><ul><li>Infusion rate </li></ul><ul><li>Delivery rate </li></ul><ul><li>Drip rate </li></ul><ul><li>Infusion time </li></ul><ul><li>Infusion volume </li></ul><ul><li>Conversion factors </li></ul>
    88. 88. Infusion Sets <ul><li>Macrodrip set chamber </li></ul><ul><li>(15 gtt/mL) </li></ul><ul><li>Microdrip set chamber </li></ul><ul><li>(60 gtt/mL) </li></ul>
    89. 89. Fluid Administration Rate <ul><li>Infusion rate </li></ul><ul><ul><li>Use patient weight and prescribed rate </li></ul></ul><ul><li>Drip rate </li></ul><ul><ul><li>Use infusion rate, delivery rate, conversion factors </li></ul></ul>
    90. 90. Preanesthetic/Preoperative Medications <ul><li>Antibiotics </li></ul><ul><li>Preemptive analgesia </li></ul><ul><li>Antiemetics </li></ul><ul><li>Anticonvulsants </li></ul><ul><li>Antiinflammatory drugs </li></ul>

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