Pre, Peri and Post-Operative Care ASR Certification Prep

Pre Operative Care Pre-Surgical Planning: Pre-surgery Examination & Blood work Fasting Set-up of prep area and operating room Thermo regulation Aseptic Preparation Analgesic Regimen Anesthesia Aseptic Transfer to Surgical Field

Pre-surgery Examination Examination should include: Physical examination and blood work in large animals Check animal identification Take and record temperature, HR, CRT, RR, BW Check cage for signs of loose stool or vomiting Observe animal in home cage for normal behaviors Review animal medical record

All animals should have free access to water. Pre-surgical Fasting Rodents & Rabbits (mice, rats, guinea pigs, hamsters, rabbits):  High metabolic rate No fasting prior to surgery Rodents DO NOT have vomit reflex, no regurgitation Monogastric animals (e.g. dogs, cats, swine): Fast 6-24 hours prior to surgery   Ruminants (e.g. sheep, goats, cattle) Fast for 12-36 hours prior to surgery. Reduces fermentation in the rumen Placing stomach tube reduces rumenal tympany. All animals should have free access to water. Restricting water results in dehydration and more difficult anesthesia.

Set-up of Prep Area and OR Ensure prep area has: Working heat support on table Functioning anesthesia machine (if required) Stethoscope Appropriate drugs and reversal agents (analgesics and anesthetics) Functioning monitoring equipment Prep supplies and clippers Vacuum Ensure OR area has: Functioning anesthesia machine (with ventilator) Fluid support as needed Emergency supplies (Ambu bag, and crash cart supplies)

OR Set Up

(e.g., table tops, equipment) RECOMMENDED HARD SURFACE DISINFECTANTS (e.g., table tops, equipment) Always follow manufacturer's instructions for dilution and expiration periods AGENT EXAMPLES* COMMENTS Alcohols 70% ethyl alcohol 85% isopropyl alcohol Contact time required is 15 minutes. Contaminated surfaces take longer to disinfect. Remove gross contamination before using. Inexpensive Quaternary Ammonium Sodium hypochlorite (Clorox ® 10% solution) Chlorine dioxide (Clidox®, Alcide®, MB-10®) Corrosive. Presence of organic matter reduces activity. Chlorine dioxide must be fresh; kills vegetative organisms within 3 minutes of contact. Glutaraldehydes (Cidex®, Cetylcide®, Cide Wipes®) Rapidly disinfects surfaces Phenolics Lysol®, TBQ® Less affected by organic material than other disinfectants Chlorhexidine Nolvasan® , Hibiclens® .Presence of blood does not interfere with activity. Rapidly bactericidal and persistent. Effective against many viruses. * The use of common brand names as examples does not indicate a product endorsement.

Aseptic Technique Preparation of the patient Bland ophthalmic ointment to eyes remove hair from the surgery site ( #40 blade, vacuum) initial or preparative scrub Povidone-iodinefollowed by alcohol rinse Chlorhexidine followed by saline rinse move to surgical room / area final surgical scrub/paint Povidone-iodine followed by alcohol rinse Duraprep®, Chloraprep® sterile draping of surgical site establish a sterile field The surgeon should direct how the animal is positioned on the table. In OR final surgical scrub should be done after the animal has been positioned and put on monitoring equipment. Establishing a sterile field: When the animal is properly positioned and antiseptically prepped for surgery, a sterile field should be created. Generally, a sterile field should be large enough to prevent accidental contamination of the incision site(s), operating team, and sterile instruments and equipment.

Alternating disinfectants is more effective than using a single agent. RECOMMENDED SKIN DISINFECTANTS Alternating disinfectants is more effective than using a single agent. AGENT EXAMPLES* COMMENTS Idophors Betadine®, Prepodyne®, Wescodyn® Reduced activity in presence of organic matter. Wide range of micobicidal action Works best in pH 6-7 Cholorhexadine Nolvasan®, Hibiclens® Presence of blood does not interfere with activity. Rapidly bactericidal and persistent. Effective against many viruses. Excellent for use on the skin. * The use of common brand names as examples does not indicate a product endorsement.

Peri-Operative Monitoring Allows: Adequate anesthesia. Adequate analgesia Adequate immobilization Early notice of trends which may develop into life-threatening conditions

Checking Anesthetic Depth Reflexes Jaw tone Eye position, pupil size and pupillary light response Heart and respiratory rates Response to surgical stimuli

Reflexes Palpebral (blink) - tested by lightly tapping the medial or lateral canthus of the eye Pedal - Elicited by pinching a digit or footpad Corneal - Tested by touching the cornea with a sterile object Laryngeal - Stimulated when the larynx is touched by an object.

Parameters to Monitor (every 10-15minutes) ECG (EKG) Peripheral Perfusion Pulmonary Monitoring Temperature Blood Pressure

ECG (EKG) An EKG measures the electric currents generated by the heart. Monitors heart function Continuous monitoring with an EKG allows early recognition of electrical changes associated with disorders of conduction in the heart and arrhythmias that may need to be treated.

ECG (EKG) Cardiac dysrhythmias: Tachycardia: excessive rapidity of the heart Bradycardia: slowing of the heart Ventricular fibrillations: total disorganization of the ventricular activity

ECG (EKG) Premature ventricular contractions (PVCs): early contraction Heart Block: loss of or non-P-wave associated QRS complexes Indicate lack of electrical transmission in the heart

Heart Rate Monitored by : Palpation of heart beat through chest wall Palpation of peripheral pulse for strength and quality Auscultation of heart beat with stethoscope Electrocardiogram (EKG, ECG) with continuous display

Heart Rate Know the acceptable HR for the species you are monitoring. Bradycardia: excessive anesthetic depth, “too deep” vagal stimulation hypertension hypothermia drug effects elevated cranial pressure Tachycardia: inadequate anesthetic level, “too light” pain/surgical stimulation hypotension hypoxemia hypercarbia

Peripheral Perfusion Capillary refill time (CRT) Measures the time taken for refilling blanched mucus membranes Observe the color of mucus membranes CRT should be 1-2 seconds and gums (when not pigmented) should be pink Other sites for color are tongue, buccal mucous membrane, conjunctiva of the lower eyelid, and the mucous membranes about the prepuce or vulva Pale membranes indicate poor perfusion, blood loss, or anemia Purple/blue membranes indicate cyanosis

Pulse Oximetry Measures the percentage of oxygenated hemoglobin and heart rate Is broadly accurate for SaO2 sensory probe needs to be placed on nonpigmented area (tongue, tail, ear ,etc.)

Pulse Oximetry Sensor beams infrared light through tissue and records the absorption either of light passing through the tissue to a receiver on the other side (transmission) or reflected back to the sensor (reflectance) Reflector sensor Transmission sensor

Pulse Oximetry Normally SaO2 is 80-90% in spontaneously breathing animals and 95-100% in ventilated animals Numbers reflect animal on 100% oxygen SaO2 readings are susceptible to lowering by positional factors (slipping away from tissue, thick tissue, pigment), vasoconstriction, drying of contact surface, and confusion with respiratory artifact Without pulse oximetry, early hypoxia can be difficult to assess as cyanosis only becomes apparent if values fall below 85% saturation.

Pulse Oximetry Monitors

End-tidal CO2 (ETCO2) Capnography measures ETCO2 concentration, at the end of an exhalation Usually somewhat lower than PaCO2 A PaCO2 measurement requires blood gas analyzer and arterial blood samples.

End-tidal CO2 (ETCO2) Accuracy is subject to mechanical factors with the breathing circuit such as volume, dead pockets, tubing diameter, gas flow, etc. Animals with ETCO2 over 30-40 mm Hg will usually breathe on their own Low ETCO2 Surgical support for cleaning and autoclaving

End-tidal CO2 (ETCO2) When displayed as a capnographic waveform much useful information may be derived such as: “Spiky” topped waves may indicate a waking animal taking short, sharp breaths Plateau with a drop to the right may indicate a leak in the circuit as the pressure of inspiration is not held

Respiration Monitored by : Observation of chest wall movement Observation of breathing bag movement Auscultation of breath sounds Audible respiratory monitor Respiratory volume may be estimated visually, by reservoir bag inflation, or by using a ventilator or ventilometer Normal tidal volume is 10-20 mL/kg/respiration Normal respiratory sounds are almost inaudible

Respiration Normal respiratory rates can vary widely Should be evaluated along with tidal volume and respiratory trends May indicate an underlying physiologic change Arrhythmic breathing patterns are usually the effect of a medullary respiratory control problem However, some abnormal patterns may be normal in certain species A Cheyne- stokes pattern is normal for horse but could be sign of heart failure or brain damage. Apneustic breathing (inspiratory hold) seen in healthy cats, dogs, and animals anesthetized with ketamine

Respiration Tachypnea: inadequate anesthetic level, “too light”, pain, hypoxemia, hypercarbia, hyperthermia, CSF acidosis, drug effects Hypoventilation : Inadequate or reduced alveolar ventilation leads to Atelectasis : partial collapse of the lung Periodic 'bagging/sighing' (every 5 minutes) throughout the procedure can prevent this. Apnea: excessive anesthetic depth, “too deep”, hypothermia, recent hyperventilation, musculoskeletal paralysis, drug effects

Respiration Harsh noises, whistles or squeaks may indicate narrow or obstructed airways or the presence of fluid in the airways. Difficult or labored breathing may indicate the presence of an airway obstruction. An abnormally low respiratory rate (<8-10 bpm) is cause for concern. Apneic animals may need to be manually ventilated throughout the procedure at a rate of 8-12 bpm.

Respiratory Acidosis Inadequate Elimination Of C02 Production Of C02 Exceeds Elimination Causes: Reduced Effective Alveolar Ventilation from: Pulmonary Edema Pneumonia Airway Obstruction Interstitial Fibrosis Inadequate Ventilation (<20 Cm H20 Intra-alveolar Pressure) slow Respiratory Rate Hypoxemia Diagnosis: EtCO2 > 45 mm Hg

Respiratory Alkalosis Enhanced Elimination Of C02 Elimination Of C02 Exceeds Production Causes: Increased Effective Alveolar Ventilation From: High Intra-alveolar pressure Hyperoxemia Hypotension Pulmonary edema Interstitial fibrosis Endogenous catecholamines (from stress) Mechanical ventilation Diagnosis: EtCO2 < 35 mm Hg

Ventilation Pressure is introduced into the trachea which inflates the lungs. Causes a significant loss in lung compliance Necessary in all procedures in the thoracic cavity. Ventilation can be severely compromised by pneumothorax, hemothorax, hydrothorax or a diaphragmatic hernia. Routine manual “bagging/sighing” of the patient can prevent atelectis.

Body Temperature Anesthetized animal lose the ability to thermoregulate normally. Will lose heat via loss of hair to shaving, the evaporation of prep solutions, evaporation at and chilling of tissues within surgical incisions, and vasodilatation caused by anesthetic agents/adjuncts Hypothermia will prolong anesthesia recovery Should be countered with warmed fluids, heating blankets, and towels/wraps Hyperthermia is also possible and dangerous May be due to overheating with heating pads and tables or due to anesthesia reactions such as malignant hyperthermia in swine Anesthetized animals lose the ability to thermoregulate normally Surgical support for cleaning and autoclaving

Body Temperature Monitor Temperature throughout surgery Ways to prevent Hypothermia Keep animal warm during induction Warm IV Fluids and irrigating solutions Circulating warm water/air blankets Pad between animal and metal table Hot water bags/bottles wrapped in towel Covering feet, hands, paws, & head Heat lamps

Blood Pressure BP = hydrostatic force that blood exerts on wall of vessels Systolic Pressure= pressure of blood when ventricles at maximum contraction Normal range 100 to 160mmHG Diastolic Pressure= pressure of blood when ventricles relax Normal range 60 to 100mmHg MAP= (2 x DP) + SP divided by 3 Normal range 80 to 120mmHg Pulse Pressure= systolic – diastolic Normal ~ 40mmHg

Blood Pressure MAP < 60 mmHg is hypotension Decreased perfusion due to low BP can cause tissue ischemia Susceptibility of tissue to ischemia depends on metabolic rate of the tissue Hypertension: Systolic >180 mm Hg and Diastolic >110mm Hg Inadequate anesthesia, partially or fully occluded airway Controlling Blood Pressure: anesthetic level IV fluids Body temperature

Blood Pressure Noninvasive/Indirect- accurately reflects trends Oscillometric method Ultrasonic Doppler

Blood Pressure Invasive/ Direct – accurate quantitative value Arterial catheter connected to pressure transducer

Immediate Post-operative Care Move the animal to a warm, dry area and monitor vital signs every 15 minutes until the animal is sternal. Turn side to side frequently to prevent pooling of fluid in recumbent side. Remove endotracheal tube when swallowing/chewing this prevents regurgitation and vomiting. Do not return to home cage until able to maintain body temperature and hold itself in sternal position.

Post-Operative Care A ”stormy “ recovery could be related to surgical pain. All animals subject to major surgery must have analgesic agents (i.e. painkillers) available to them for at least the initial 24-48 hours post-surgery Provide analgesics as directed by veterinarian.

Post-Operative Care Daily evaluation parameters: appearance attitude appetite Hydration TPR Signs of pain Surgical Incision - for clinical signs of infection, seroma, hematoma, suture breakdown, wound dehiscence.

Post-Operative Care Administration of drugs Suture/Staple Removal SID or QD once daily BID twice daily TID three times daily QID four times daily Suture/Staple Removal The goal of the staples / sutures are to keep the skin margins closed. Evaluate incision healing prior to removal Normal removal time is 10 to 14 days

References NIH website http://oacu.od.nih.gov/ARAC/surguide.pdf Duke University Animal Care and Use Program http://vetmed.duhs.duke.edu/guidelines_for_general_surgery_in_animals.htm Doctors Foster and Smith Website http://www.peteducation.com/article.cfm?c=0+1302+1478&aid=977 http://www.ruralareavet.org/PDF/Anesthesia-patient_Monitoring.pdf