Anesthesia Monitoring and Pa0ent Safety. Lauren Kreisberg, RVT

Transcription

1 Anesthesia Monitoring and Pa0ent Safety Lauren Kreisberg, RVT

2 Pa0ent History Presen0ng Complaint Age Sex (current estrus cycle in intact females) Medica0on history including all OTC medica0ons, and adverse drug (anesthe0c and non- anesthe0c) reac0ons Diet Behavior changes or decreased ac0vity Coughing/Sneezing/Vomi0ng/Diarrhea PU/PD Exercise intolerance Seizure ac0vity or history of collapse

3 Temperature Pulse Respira0ons MM/CRT Body condi0on score Lymph node palpa0on Abdominal palpa0on Oral exam Hydra0on status Overall demeanor ASA Status Pre- op Exam

4 ASA Status American Society of Anesthesiologists offers the following taxonomy to categorize pa0ents with varying levels of anesthe0c risk; I- healthy pa0ent II- mild systemic disease with no func0onal limita0ons III- severe systemic disease with definite func0onal limita0ons IV- severe systemic disease that is a constant threat to life V- moribund pa0ent unlikely to survive 24 hours (with or without surgery) E (for emergency) may be added to any of the above classifica0ons and denotes pa0ents that may face addi0onal inherent risks secondary to the performance of hasty surgical procedures. I0s important to consider and assess mul0ple factors prior to anesthe0zing every pa0ent.

5 Preopera0ve Diagnos0cs Full blood panel (ideally) though PCV/TP, BUN (azos0x), and BG at minimum. Urinalysis (ideally), but urine specific gravity at minimum. Radiographs, ultrasounds, blood pressure measurements, ECG recordings may also be helpful, and/or necessary depending on the pa0ent status.

6 Special Considera0ons Neonates (newborns up to 8 weeks of age) Pediatrics (8 weeks of age through 3 months) All major organ systems (cardiovascular, thermoregulatory, pulmonary, renal and hepa0c) are rela0vely mature by 3 months of age. Geriatric Sick Trauma

7 Neonates and Pediatrics Hypothermia small surface area Hypoglycemia - monitor BG and supplement with IV dextrose PRN NPO no more than 4 hours prior to surgery Higher res0ng respiratory rate due to increased oxygen demand Small airways which can easily be obstructed Cardiac output is heart rate dependent Periodic assisted ven0la0on. Low doses of injectable anesthe0c agents including seda0ves should be used

8 Geriatrics Decreased blood volume and blood pressure Reduced cardiac output with increased circula0on 0me Use of lower doses of injectable seda0ves and anesthe0cs is recommended. Fluid therapy and blood pressure monitoring is cri0cal because renal perfusion can be decreased. Hypothermia is common due to abnormali0es within the hypothalamus caused by age.

9 Other Important Factors Type of procedure being performed Pa0ent posi0oning and affects of such posi0oning Breed specific anatomy Pa0ent temperament

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11 Pre- Induc0on Test anesthe0c machine and ET tubes for leaks Make sure the pop off valve is open and there is inhalant in the vaporizer chamber Re- evaluate TPR a_er premed drugs to determine if any other drugs (such as an an0cholenergic), or heat therapy may be needed. Measure endotracheal tube length prior to intuba0on and cut tube if needed. The external landmark for proper intuba0on is the thoracic inlet.

12 Proper Endotracheal Tube Placement Don t be afraid to cut tubes!

13 Murphy s Eye

14 Induc0on Preoxygenate pa0ent for about 5 minutes if the pa0ent will tolerate a mask or at least flow- by O2. Inject induc0on agent to desired affect so that endotracheal intuba0on may be established. Use the largest diameter ET tube that will fit comfortably between the arytenoid car0lages without damage.. Start pa0ent on the flow of oxygen and inhalant anesthe0c. *Flow rates and anesthe0c concentra0ons will vary depending on the level of seda0on brought on by premedica0on drugs, and/or ongoing disease status.*

15 Induc0on Con0nued Inflate cuff and check for leaks around the cuff. Leaks at 20cm H20 are ok! Lubricate eyes with ar0ficial tears ointment and re- apply every 2 hours of anesthesia and a_er giving an an0cholenergic drug.

16 Anesthesia Monitoring There are no safe anesthe0c agents, there are no safe anesthe0c procedures. There are only safe anesthe0sts. - Robert Smith, MD The primary goal of monitoring anesthe0zed animals is to ensure adequate 0ssue perfusion with oxygenated blood.

17 Inhalant Anesthe0c Side Effects Respiratory depression Vasodila0on Hypotension Decreased cardiac output CNS Depression Muscle relaxa0on

18 Monitoring Equipment Stethoscope Pulse oximetery Electrocardiography (ECG, EKG) Blood Pressure (Direct and Indirect) Capnography

19 Stethoscopes Stethoscopes are used externally to evaluate heart rate and rhythm but do not provide relevant informa0on regarding cardiac func0on or output. Esophageal stethoscopes are wonderful tools that remain in place throughout the dura0on of a procedure. They provide con0nuous monitoring of both respiratory and cardiac func0on by allowing evalua0on of intensity, dura0on, and quality of both breath and cardiac contrac0ons.

20 Esophageal Stethascope

21 ECG and SpO2 Electrocardiography (ECG, EKG) monitoring is used to diagnose cardiac dysrhythmias during anesthe0c procedures. ECG monitors the electrical ac0vity within the heart, not chamber size or efficiency of blood pumping. Pulse oximeters provide con0nuous and non- invasive pulse monitor while also giving an es0mate of hemoglobin satura0on.

22 Blood Pressure Determined by cardiac output and total peripheral resistance. All animals will experience some degree of hypotension while under anesthesia. Indirect blood pressure monitoring is most common in small animal prac0ce either by using a Doppler or an oscillometric device. Monitoring goals- systolic value > 90mmHg <160mmHg, MAP >60mmHg

23 Blood Pressure Cuff size is crucial for accurate results. In dogs, the width of the cuff should extend 40-60% of the circumference of the limb. In cats, 30% is acceptable. Common cuff loca0ons are either hindlimb or forelimb just proximal to the tarsus or carpus. The proximal tail can be used in place of a limb.

24 Capnography The measurement of expired carbon dioxide present at the end of a breath. This number can be used to evaluate the adequacy of pa0ent ven0la0on and anesthe0c depth. Helpful when determining the effec0veness of PPV during anesthesia or CPCR. Normal ET C02 is approximately mmhg in pa0ents under anesthesia. Increasing ET C02 commonly means excessive anesthe0c depth, and requires immediate aqen0on.

25 Capnography Wave Forma0on

26 Irregular Wave Forma0on

27 Monitoring Without Equipment MM CRT Pulse strength (femoral, digital, sublingual) Jaw Tone/Muscle Relaxa0on Eye posi0on: Light- central, constricted pupils Medium (Ideal)- ventral/medial rota0on, third eyelids up. Deep- central, dilated pupils

28 Puung It All Together When to adjust the vaporizer Check the tube for proper length and cuff infla0on Control pain, don t mask it Check all other parameters first When to adjust the oxygen flow Pa0ent temperature How full is the rebreathing bag? Inspired CO2 value

29 Recovery Begins when the anesthe0c gas is turned off, and does not end at the 0me of extuba0on. Con0nue all methods of non- invasive pa0ent monitoring throughout recovery process. Respiratory depression persists during the early recovery phases. Extubate only when the animal can adequately protect its airway by swallowing. Hypothermia will delay recovery so all efforts to achieve normal temperatures should be made. Express or drain bladder if pa0ent received a large amount of fluid during the procedure to ease any discomfort.

30 Ques0ons???

31 References Anesthesia for Veterinary Technicians, Edited by Susan Bryant, CVT, VTS (Anesthesia) Who Needs an Anesthe0c Plan? YOU DO!- Heidi Reuss- Lamky, LVT, VTS (Anesthesia) WVC 2013 Conference notes AAHA Anesthesia Guidelines for Dogs and Cats 2011 Anesthesia Monitoring, Oklahoma State University, Dr. Lyon Lee DVM, Ph.D