ANESTHETIC PROBLEMS AND EMERGENCIES

1. ANESTHETIC PROBLEMS AND EMERGENCIES The Role of the Veterinary Technician in Emergency Care

2. ANESTHETIC PROBLEMS AND EMERGENCIES 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!

3. ANIMALS THAT WILL NOT STAY ANESTHETIZED • Animals won’t stay anesthetized • Check vaporizer setting • Check level of anesthetic in the vaporizer • Proper ET tube placement or air leakage around it • Patient apnea • Shallow respirations • Proper assembly of anesthetic machine with tight connections • Adequate oxygen flow • Anesthetic machine/vaporizer is working properly • Agonal breathing vs. light plane breathing

4. ANIMALS THAT ARE TOO DEEPLY ANESTHETIZED • Animals are too deeply anesthetized • <6 bpm; shallow respirations, dyspnea • Pale/cyanotic mucous membranes • Capillary refill time >2 seconds • Bradycardia • Weak pulse; systolic blood pressure <80 mm Hg • Cardiac arrhythmias; irregular QRS complexes or VPCs • Hypothermia • Absent reflexes • Flaccid muscle tone • Dilated pupils

5. TREATING EXCESSIVE ANESTHETIC DEPTH • ADJUST THE VAPORIZER: • NOTIFY THE VETERINARIAN: • BAG THE ANIMAL • 1. Close the pop-off valve • 2. fill the reservoir bag with oxygen • 3. gently squeeze the bag until the patient’s chest rises slightly (15-20 cm H2O) • 4. Repeat until animal shows signs of recovery

6. PALE MUCOUS MEMBRANES • Pale mucous membranes • Preexisting conditions • Blood loss during surgery • Anesthetic agent that causes vasodilation and hypotension • Hypothermia • Pain

7. TREATMENT OF PALE MUCOUS MEMBRANES • Ascertain the animal’s anesthetic depth: • HR, RR, pulse quality, CRT • Consult the veterinarian • Fluids, blood transfusion

8. Anesthetic Problems and Emergencies (Cont’d) • Prolonged capillary refill time (>2 seconds) • Blood pressure cannot adequately perfuse superficial tissues • May result from conditions present prior to induction • May be secondary to blood loss during surgery • May be seen in animals in deep anesthesia

9. DYSPNEA AND/OR CYANOSIS • DYSPNEA: respiratory difficulty • CYANOSIS: bluish coloration of the mucous membranes indicating inadequate tissue oxygenation • Assessment • Respiratory character and volume • Depth of anesthesia • Associated with pain • Proper ET tube placement • ET tube blockage • Oxygen saturation • Arterial or end-tidal CO2

10. Treatment of cyanosis/dyspnea 1. Check O2 flow meter 2. Turn off vaporizer and begin to bag the patient (IPPV) • If the anesthetic machine is unavailable, an Ambu bag can be used to deliver room air 3. Reintubate if necessary 4. Continue until patient improves 5. Close monitoring to ensure that cardiac arrest does not occur • Radiographs and thoracocentesis might be needed

11. TACHYPNEA • TACHYPNEA: rapid respirations • CAUSES: • Surgical stimulation • Commonly seen with opioid use • Associated with light anesthesia accompanied by tachycardia and spontaneous movement • May be seen in hyperthermic animals

12. TREATMENT OF TACHYPNEA • CHECK ANESTHETIC DEPTH • Is the animal too light? • CAPNOGRAPH READING • Obese patients • Assist or control ventilation

13. RESPIRATORY ARREST • Not all cases require immediate action by the anesthetist: • Cessation of respiratory efforts • Can lead to cardiac arrest • Temporary arrest • May follow injection of respiratory depressants or following a period of prolonged bagging • Evaluate other vital signs • HR/pulse quality: • MM: • ECG • Pulse oximeter reading:

14. Respiratory arrest (Cont’d) • True arrest • Requires immediate action • Can result from anesthetic overdose, cessation of oxygen flow, or preexisting respiratory disease • May be preceded by dyspnea or cyanosis and abnormal vital signs • May use Ambu bag, mouth-to-ET tube, or mouth-to-muzzle resuscitation

15. Use of an Ambu Bag

16. TREATMENT OF TRUE RESPIRATORY ARREST • 1. NOTIFY THE VETERINARIAN • 2. Turn off the vaporizer • 3. Place ET tube if not already done • Emergency tracheotomy? http://www.youtube.com/watch?v=3doQewrHdhQ • 4.Monitor for cardiac arrest • 5.Restore oxygen flow and begin bagging the patient • 6. Continue bagging every 5 seconds until vital signs improve • 7. Administer shock fluids- Dr. can decide on Dopram or reversal • 8. Preserve warmth

17. CARDIAC ARREST • Cardiac arrest • No heartbeat is auscultated or palpated • Normal QRS complexes are absent • No arterial pulse and blood pressure <25 mm Hg • Gray or cyanotic mucous membranes • Widely dilated pupils, no corneal reflex • Agonal breathing • Some prior warning is usually present • Respiratory distress or arrest, cyanosis/dyspnea, prolonged capillary refill time, arrhythmia

18. CPR CardioPulmonary Resuscitation Updated with information from the ACVECC-RECOVER Study 2012 http://www.acvecc-recover.org/

19. Anesthetic Problems and Emergencies • Cardiac arrest with CPCR (cardio-pulmonary cerebrovascular resuscitation) • A = airway • B = breathing • C = circulation • D = drugs • E = ECG • F= Fluids • Circulation is the most important step so the correct order is CABDE

20. CPR • Human Medicine • Cardiac arrest: 330,000 people per year die • Survival to discharge: • Out-of-hospital arrest: <6.4% • Veterinary Medicine • Total arrest numbers unknown • Survival to discharge: • In-hospital-arrest: • Dogs 4% • Cats 4-9.6%

21. PREVENTION • The most successful CPR is one that is averted! • Know which patients are risk. • Know the warning signs.

22. Risk Factors • Cellular hypoxia • Hypercarbia • Vagal stimulation • Arrhythmias • Severe anemia • Acid-base abnormalities • Electrolyte abnormalities • Anesthesia • Trauma • Systemic and metabolic diesease

23. Warning signs • Changes in respiratory rate and character • Weak irregular pulses • Bradycardia • Hypotension • Cyanosis • Hypothermia

24. Preparedness/Readiness • Time is critical • To Increase chances of success… • Early recognition • Know patient’s code status • Personnel • Dedicated space • Equipment

25. Recognition of arrest • Loss of consciousness • No respirations • No palpable pulses • Pupils fixed and dilated • CRT prolonged or absent • MM pale, grey, cyanotic

26. Who should be resuscitated? • Patients with reversible disease • When doubts exist perform CPR • Discuss and educate client at admission!

27. Personnel responsibilities • There is a critical 4 MIN window to restore oxygen delivery to the brain! • Team Effort: Doctors and Technicians (5 techs 1 doctor) • Central person making decisions (DVM) • Chest compressions • Manual ventilation • Drug administration • Setting up monitoring equipment • Recording events

28. Dedicated space Hard Surface Oxygen source

29. Crash Cart • Cuffed endotracheal tubes • 4-6 sizes • Laryngoscope • Syringes, needles of various sizes • Catheters: Intravenous, intraosseous, red rubber • Defibrillator • Drugs • Epinephrine, atropine, vasopressin • Naloxone • Small surgery pack • Suction unit

30. Phases of Resuscitation • Basic Life Support • ABC’S • Advanced Life Support • ABC plus D: Drugs & Defibrillation • Post-Arrest: Prolonged Life Support

31. ABC’s • Airway • Should have 4-6 sizes of cuffed ET tubes available • Laryngoscope • Make sure airway is clear • Suction airway if necessary Capture and secure airway!!

32. CARDIAC ARREST - ABCDEF • AIRWAY and BREATHING; IMMEDIATELY CALL FOR HELP, NOTE THE TIME! • An Endotracheal tube must be placed! • Begin bagging at 1 breath every 10-12 seconds (1:5 breath to compressions) • Do not overinflate

33. Breathing • Utilization of ambu bag connected to oxygen source • Provide manual ventilatory support • Ventilation of dogs and cats with CPA at a rate of 10 breaths per minute with a tidal volume of 10ml/kg and an inspiratory time of 1 sec is recommended.

34. Circulation • External chest compressions • Thoracic pump theory • Cardiac pump theory • Positioning • Lateral recumbency • Firm surface Medium and large dogs Small dogs and cats

35. CARDIAC ARREST - ABCDEF • CIRCULATION – cardiac compressions should be initiated Compressions manually force blood through the heart and into tissues • POSITIONING: right side down with legs toward the compressor • LARGE DOGS: The heel of the compressor’s hand should compress the chest against a firm object placed under the dog’s chest just behind the elbow. Also, dog can be placed in dorsal recumbency and compression applied to the caudal 1/3 of the sternum

36. CARDIAC ARREST - ABCDEF • Medium sized dogs: The chest is compressed between two hands, one underneath the chest and the other at the 5th intercostal space over the heart itself. • Small dogs or cats: compression applied using the thumb to compress the chest against the fingers of the same hand.

37. Circulation • Most important factor is return of spontaneous circulation (ROSC) • Cardiac compressions • Each compression should produce a palpable femoral pulse • Rate of compressions : 100-120/ minute • Compressions should be continuous • Allow full chest wall recoil • 30-50% chest compression depth • 1:1 ratio compression/relaxation • Change compressor every 2 minutes

38. Circulation (Cont’d) • Bag the patient every 10-12 seconds • Simultaneously with compressions • Some results should be seen within 2 minutes • Internal compressions may be necessary • Resuscitation is unlikely to be successful after 15 minutes • Once spontaneous cardiac contractions are established, continue bagging until spontaneous breathing is established (several hours)

39. These patients are not on their right side- boooo

40. Indications for open chest CPR • Owner wishes?? • Thoracic trauma • Pericardial fluid • No response to CPR after 3-5 minutes • Chest or abdominal surgery

41. Advanced Life Support • ABC plus D • Drugs • Defibrillator • Doppler • Veterinarian authorizes dosage, route, and nature of drugs

42. Drugs • Epinephrine – 0.01 mg/kg • Alpha 2-adrenergic stimulator: vasoconstriction • Give every 3 to 5 minutes during CPR • Atropine – 0.05 mg/kg • Anticholinergic parasympatholytic: Increases HR • Give every 3 to 5 minutes during CPR • Asystole and PEA • Vasopressin – 0.8 u/kg • Peripheral vasoconstriction • Dilation of cerebral vasculature • Asystole, prolonged arrest • Dopamine or dobutamine • Increase force and rate of cardiac contractions

43. Drug Dose Chart From: www.ACVECC-RECOVER.org

44. Drug admnistration routes • IV (intravenous) • IT (intratracheal) • Double dose of drug • Never give Na bicarb IT • IO (intraosseous) • IC (intracardiac) NOT RECOMMENDED • Risk of coronary vasculature laceration in closed-chest • OK in open-chest

45. ECG • Monitor/Assess • Rhythm • Electrical activity

46. Common Initial Arrest Rhythms Ventricular fibrillation PEA (pulseless electrical activity) Asystole

47. Asystole • Most common arrest rhythm • NO drugs have proven effective • Vasopressin shows some promise • Continue CPR or stop

48. Pulseless Electrical activity • Electrical activity but no myocardial contraction • Formerly know as EMD (electrical mechanical dissociation) • NO drugs proven effective • Continue CPR or stop

49. Ventricular Fibrillation • Two forms • Coarse • Higher amplitude more orderly appearance • Easier to convert with defibrillation • Fine • Lower amplitude, complete lack of organization • Carries poorer prognosis, more difficult to convert • Can be mistaken for asystole • Recommended treatment: Immediate defibrillation

50. Advanced Life Support: cont • Defibrillation • One shock • External: • 4-6 J/kg Monophasic • 2-4 J/kg Biphasic • Internal: 0.2-1 j/kg • No alcohol(ecg)