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

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!

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

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

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

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

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

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

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

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

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

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

RESPIRATORY ARREST Cessation of respiratory efforts 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:

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

Use of an Ambu Bag

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

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

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

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

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

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

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

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

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

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

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

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

Dedicated space Hard Surface Oxygen source

Crash Cart Cuffed endotracheal tubes Laryngoscope 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

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

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!!

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

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.

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

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

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.

Circulation Cardiac compressions 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

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)

These patients are not on their right side- boooo

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

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

Drugs Epinephrine – 0.01 mg/kg Atropine – 0.05 mg/kg Alpha 2-adrenergic stimulator: vasoconstriction Give every 3 to 5 minutes during CPR Atropine – 0.05 mg/kg Anticholinergic parasympatholytic: Increases HR 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

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

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

ECG Monitor/Assess Rhythm Electrical activity

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

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

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

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

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)

Auscultation, palpation of pulses Monitoring ETCO2 Doppler on cornea ~Cerebral blood flow Auscultation, palpation of pulses

Advanced life support: cont- Fluids IV fluids (crystalloids) IF EUVOLEMIC: *DO NOT GIVE SHOCK DOSES* Decreased CPP Increased right atrial pressure relative to aortic pressure If hypovolemic Shock dose: 90ml/kg dogs, 40-60ml/kg cats Start with ¼ shock dose

Monitor cardiovascular and respiratory function Blood pressure, blood gases, pulse oximetry, ECG, capnography Drug and fluid therapy varies Assess brain function Repeat arrest within 24 hours is common Following successful ROSC, other conditions may arise Pulmonary or cerebral edema

Wrap Up Prevention Preparedness Early recognition Know patient’s code status Dedicated space, personnel, equipment KNOW YOUR ABC’s!

Other occurrences during surgery but not necessarily an emergency Regurgitation during anesthesia A passive process under anesthesia No retching, just fluid draining from animal’s mouth or nose Stomach contents may be aspirated into respiratory tract Most common occurrence in head-down surgical positions and in ruminants Treatment Immediate placement of cuffed ET tube Clean out regurgitated material with suction

Post op complications Vomiting during or after anesthesia Common in brachycephalic dogs or nonfasted animals An active process usually accompanied by retching Usually occurs as the animal is losing or regaining consciousness Signs Airway obstruction leading to dyspnea/cyanosis, bronchospasm Treatment Intubation and suction if unconscious Lower head and clean oral cavity if conscious

Seizures Seen with ketamine administration, after diagnostic procedures (myelography), or preexisting conditions Signs Spontaneous twitching; uncontrolled movements of head, neck, and limbs; opisthotonus; triggered by a stimulus Treatment Reduce stimuli, postoperative analgesia, diazepam or propofol, monitor for hyperthermia

Seizures should be differentiated from excitement Seen after barbiturate anesthesia or high opioid doses, as spontaneous paddling and vocalization Treatment may not be necessary Sedatives may help Naloxone can reverse opioids Seizures should be differentiated from excitement

Dyspnea in cats Dyspnea is usually caused by laryngospasm sometimes triggered by removal of the ET tube Laryngeal edema may result from repeated intubation attempts May breathe with an audible stertor (wheeze) during inspiration Differentiate from growling during expiration May resolve itself or may need oxygen administration via facemask, intubation, or a tracheotomy Is easier to prevent than treat

Dyspnea in dogs Breed-related Airway obstruction Brachycephalic dogs Airway obstruction Anatomy, foreign objects, postsurgical tissue swelling Humidified oxygen can be delivered to an awake animal By facemask, nasal cannula, E-collar, or oxygen cage/tent