Cardiopulmonary Arrest Cardiopulmonary Cerebral Resuscitation Emergency Nursing: Cardiopulmonary Arrest and Cardiopulmonary Cerebral Resuscitation Pgs. 921-926 CTVT

Emergency Care Area *** Requirements Central location Easy access Dedicated “crash table” Basic necessary equipment Oxygen source Suction unit Surgical lighting Multiple electrical outlets Other useful equipment ECG and defibrillator, blood pressure machines. Reference Fig. 33-8: Emergency procedures and supplies needed. Other important items include various size oxygen masks, reservoir bags, and asthmatic inhaler as indicated in PP picture.

Crash Cart *** Organize and prioritize drawers according to the ABC’s A=airway B=breathing Thoracocentesis materials for emergency respiratory patient Venous access (C=circulation) Venous access drawer Various size and length catheters Reference crash cart contents (pages 6-11) and check list. Emphasize checking drawers per shift. Check endotracheal cuffs prior to placement in the drawer. Ensure tie gauze, suction, etc., is in airway drawer. Discuss keeping drug drawer neat, well-labeled, and organized.

Laboratory Equipment *** Minimum database “QATS” (quick assessment test) Lactate testing Additional point of care testing Blood gases Coagulation testing Commercial test kits Ethylene glycol Reference laboratory equipment required for emergency response. Review suggested minimum database required: PCV, total protein, blood glucose, azostick. Additional point of care: testing such as arterial blood gases, and other useful emergency commercial test kits, such as ethylene glycol test kits. Discuss usefulness of monitoring blood lactate; elevated values (>2.5g/dl) indicates tissue hypoxia, or poor perfusion.

Principles of Triage *** Set protocols for a consistent, thorough response A CRASH PLAN Be well-organized Expect the unexpected Set protocols are necessary for consistent, thorough evaluations. Use systematic “check-offs” in triage to evaluate the most life-threatening problem first—usually the respiratory system. Mnemonic devices such as a CRASH PLAN (Box 33-1) in stressful situations help to avoid a chaotic, unorganized response when time may not be a luxury.

Definitions *** Cardiopulmonary arrest Cessation of breathing and effective blood circulation

Definitions *** Cardiopulmonary Resuscitation (CPR) Providing ventilation and assisted circulation Cardiopulmonary Cerebral Resuscitation (CPCR) Acronym emphasizes the importance of maintaining perfusion and oxygen delivery to the central nervous system during and after an arrest

Definitions *** Vagal arrest: Caused by heightened vagus nerve stimulation or vagal tone Common diseases associated with vagal arrests Gastrointestinal disease Respiratory disease Neurological disease Ophthalmic disease The vagal arrest from vomiting occurs by a reflex slowing of the heart, mediated by the vagus nerve. In weak and debilitated animals, bradycardia can be severe and lead to cardiac arrest. Severe straining associated with urination or defecation can produce similar, and detrimental, results. Most common source of vagus-mediated arrest is weak and vomiting animals.

Cardiopulmonary Arrest *** Cardiopulmonary arrest is a potential complication in: any critical illness healthy patients undergoing anesthesia

Patients at Risk For an Arrest *** Respiratory difficulty Heart disease Severe hypothermia Multi-organ failure Trauma Shock Any critical patient is at risk for an arrest. Good communication between the veterinarian and technician is paramount to providing good care. Monitor patients closely for any signs of deterioration or changes in mentation.

Patients at Risk for an Arrest Anesthetized patients Monitor for unexplained changes in anesthetic depth Frequently monitor vital signs during entire procedure Monitor closely after anesthesia Support perfusion with fluids, heating pads Prevention of an arrest begins with the technician’s attitude. Be cautious even if the procedure is routine; monitor the patient as if it were your own pet. Take your time and do not rush through an examination, procedure, or anesthetic recovery. Re-evaluate critical patients frequently, as well as any patient during triage.

Reassessment Campaign On Veterinary Resuscitation RECOVER GUIDELINES ADDRESS: Preparedness and prevention Basic Life support and Advanced Life Support Monitoring Post-resuscitative care

RECOVER: Preparedness and Prevention At best we should try to prevent CPA Prepared facilities Necessary equipment and supplies (in a central location) Check frequently for inventory content and function Provide dosing charts and algorithms Staff prepared team members Standardize training Have practice drills Debriefing session after every CPR event

CPCR Protocols: BASIC LIFE SUPPORT First step Once a diagnosis of CPA is made, CALL FOR HELP! BLS is best performed with a minimum of 2-3 people

CPCR Protocols Basic Life Support creates artificial circulation to supply oxygenated blood to the body the organs of most concern are the heart, lungs, and brain Airway Circulation Breathing OR Airway Circulation Breathing Current protocols may advocate the “CABs” to reflect the importance of restoring perfusion during the resuscitation efforts.

CPCR Protocols A = Airway If respirations are absent or weak, the mouth should be opened and examined for possible obstruction Common obstructions to airway include mucus secretions, vomitus, blood, ingested foreign material, or extraneous tissue or masses. Airway should be cleared if possible to facilitate intubation. Suction or tissue forceps and gauze can be used to remove obstructions.

CPCR Protocols B = Breathing Visualize airway with laryngoscope Pull tongue forward with dry gauze to facilitate tube passage Suction readily available Stylets readily available Ventilate at a rate of 10 breaths/min or a breath every 6 seconds Inspiratory time: 1 sec Suction and stylets should be readily available if intubation is difficult. Lidocaine spray can also be used for arytenoid spasms. If intubation is not possible, a narrow orotracheal catheter or transtracheal cannulae can be used.

CPCR Protocols B = Breathing First two breaths administered should be long breaths lasting a full 2 seconds followed by patient assessment If voluntary breathing is not immediate, manually ventilate Follow initial ventilation by assessing patient; spontaneous ventilation may be possible. If the patient does not begin to take breaths on its own, manual ventilation must begin immediately. If the patient was undergoing anesthesia, immediately turn off inhalant gas, leaving the patient to breathe 100% oxygen.

CPCR Protocols Ventilation Goal: expand the chest by 30% with a slightly longer expiration than inspiration Inspiratory Pressures 20 cm H2O dog 15 cm H2O cat All personnel involved with resuscitation efforts need to be able to work the pop-off valve, and ensure that the proper size tubing and reservoir bag are appropriate size for the patient. Monitor pressure by watching needle on gauge; most Ambu-bags do not have a pressure dial.

An endotracheal tube connected to an Ambu bag and oxygen source provides an ideal means to supply 100% oxygen and manual assisted ventilation.

CPCR Protocols B = Breathing If intubation is not available, and/or the situation is single person CPR, mouth-to- snout ventilation should be considered Mouth-to-nose resuscitation may be performed by sealing the lip margins and blowing into the animal’s nose 2 breaths every 30 compressions for single person CPR Neonates may be intubated with a small red rubber catheter; oxygen can be delivered carefully by blowing through the tube Mouth-to-nose ventilation is inadequate and should be only temporary until more oxygen can be provided; this type of resuscitation does carry some risk of exposure to potentially zoonotic diseases.

CPCR Protocols Failed respiratory resuscitation may respond to acupuncture to labial fulcrum Insert 25 g needle 1.0 mm and twist The acupuncture point is Governor Vessel 26 (VG 26) of Jen Chung. This point is located at the nasal philtrum at the level of the ventral edge of the nares (refer to Fig. 33-27).

CPCR Protocols C = Circulation Once the airway is established and ventilation provided, assess circulation Palpation of pulses (or apex heart beat) Auscultation of the heart Some animals suffer respiratory arrest without cardiac arrest. In addition, peripheral pulses are typically not palpable when the mean blood pressure is <60 mm Hg. An apex heartbeat may be indistinguishable when the pressure is <40 mm Hg.

CPCR Protocols Initiate chest compressions Positioning of animal Depends on the animal’s size Shape of the chest (barrel chest vs. deep and narrow chest) The caregiver’s ability to deliver adequate compressions A stepstool or a crash table that can be moved up or down can facilitate chest compressions.

CPCR Protocols Cardiac pump method – manual pressure is applied directly to the heart which causes blood to flow out of the chambers Animal is in rt. or lft. lateral recumbency Place palm over heart; hand-over-hand Compress chest to 1/3-1/2 its width Place stack of towels under patient’s heart if necessary Small dogs or cats may place sternal and compress ventrally “Tennis-ball” technique To optimize the cardiac and thoracic pumps, animals <15 lb (7 kg) should be placed in lateral recumbency. Smaller patients may be propped sternal and compressed ventrally with one hand (like a tennis ball) for cardiac contractions.

CPCR Protocols Thoracic pump method – compressing the chest wall causes a decrease in the volume of the chest cavity and an increase in intra-thoracic pressure, forcing blood out of the thorax Hands are placed at the widest part of the chest Upon release of the compression, a negative pressure gradient is created by the normal recoil of the chest This promotes flow back into the thoracic cavity and the heart Recommended for most large and giant breed dogs

CPCR Protocols KEYS TO SUCCESSFUL CARDIAC COMPRESSION Allow time between compressions for adequate ventricular filling Improved CPR outcomes are associated with uninterrupted chest compressions Cycles of 2 min Alternate person providing compressions Rate of 100-120bpm Interposed abdominal contractions Alternate with external chest compression Interposed abdominal and thoracic compressions may increase resuscitation statistics by theoretically increasing venous return. Compression rates are typically 120/min for animals <15 lb and 80-100/min for animals >15 lb. Administering ventilations and chest compressions simultaneously enhances the thoracic pump by increasing intrathoracic pressure during the compression (systole) and increasing venous return and atrial filling during relaxation (diastole).

CPCR Protocols Interposed abdominal compressions

Open-Chest CPCR Indicated in animals with chest trauma Open-chest CPCR is only beneficial if initiated early in the resuscitation effort Open-chest CPCR should be initiated within 2 minutes of cardiopulmonary arrest This is the purest example of cardiac pump method The role of the technician in open chest CPCR is to assist the veterinarian with sterile instruments, suction, and continued ventilation. Sterile emergency packs, sterile surgical gloves, adequate lighting, and sterile suction must be readily available. Record all events and drug administration into the medical record or on a standardized CPCR form.

Advanced Life Support Advanced Life Support is the addition of ECG and vital sign monitoring to support drug administration and other therapies such as fluid therapy, and defibrillation techniques Administration of drugs Drug choices based on cardiac output, blood pressure, and presence of arrhythmias Evaluate need for fluid or colloid therapy ECG monitoring Defibrillation techniques

CPCR Protocols Administration of drugs Common drugs used in CPCR Atropine – treats asystole, promotes/increases heart rate Epinephrine – vasopressor, positive inotrope, chronotrope Naloxone – reversal agent for opioids Lidocaine – anti-arrhythmic agent for ventricular arrhythmias Vasopressin - vasopressor Magnesium chloride or sulfate – used for chemical defibrillation

CPCR Protocols Drug administration May be ineffective due to poor perfusion A central vein catheter is the CPCR drug administration route of preference during closed- chest CPCR Although drug delivery is most effective through a central line, this is not necessarily the easiest or fastest means to obtain vascular access if the critical patient does not yet have an intravenous catheter. The fastest route in this situation would be intratracheal; attempt a peripheral IV catheter placement for rapid fluid delivery.

CPCR Protocols 2nd option for Drug Delivery Intratracheal LEAN or NAVEL Double the IV dose Third option for Drug delivery Peripheral Intra-osseous (RECOVER guidelines says this is a first option) Last option - Intracardiac as last resort Difficult to hit a flaccid heart More damage may occur Use 1/10 of the IV dose Acronym LEAN can be used to remember which drugs can be administered by the intratracheal route (lidocaine, epinephrine, atropine, and naloxone). Intratracheal drugs are administered via a catheter passed through the endotracheal tube (Fig. 33-36). Insertion of drug into the intratracheal catheter must be followed by a flush of air or saline to ensure drug deposition into the airways; a deep breath administered via manual ventilation helps to further distribute the drug. Drug doses administered by the intratracheal route may be rapidly estimated by doubling the IV dose; small drug volumes may require dilution for effective administration. Presence of pulmonary edema may hinder absorption. Third best route of drug delivery in CPCR is via a peripheral catheter; fluid administration is superior by this route, since it is typically a shorter, larger bore catheter that will facilitate rapid fluid boluses. Intracardiac option is the last resort since it is difficult to hit a flaccid heart, and for the risk of damaging the heart. However in open-chest CPCR, intracardiac drug administration is preferred; usually, one-tenth of the intravenous dose is injected directly into the left ventricle.

A polypropylene catheter passed through an endotracheal tube can be used for the intratracheal administration of some drugs during CPCR.

CPCR Protocols ECG Allows recognition of specific arrhythmias so that appropriate drugs are administered Evaluate at the end of every 2 minute cycle Allows for response to therapy to be assessed

Three Arrhythmias Seen During an Arrest Asystole (“flat-line”) Treated with atropine and/or epinephrine; repeated doses if no response is observed Electromechanical dissociation (EMD) Treated with naloxone, megadose atropine, or epinephrine Asystole (Fig. 33-30) EMD or pulseless electrical activity (Fig. 33-31) Ventricular fibrillation (Fig. 33-32) Bradycardia is also a common sequela to poor perfusion and hypoxia; treatment is small increments of atropine. EMD can have the presence of ECG complexes with no cardiac contractions to generate a pulse (which is why this arrhythmia is also called pulseless electrical activity or PEA).

Three Arrhythmias Seen During an Arrest Ventricular fibrillation Treatment is by electrical defibrillation using an electrical defibrillator Chemical defibrillation may be attempted using drugs such as magnesium chloride A strong precordial thump is potentially effective as a last resort Ventricular tachycardia (on the left of the ECG) suddenly degenerates into ventricular fibrillation (on the right side of the ECG).

An electrical defibrillator and ECG should be located on top of the crash cart for treatment of ventricular fibrillation during cardiac arrest.

Three Factors to Consider in Defibrillation Paddle surface should be as large as will fit on the surface of the chest wall or cardiac muscle Should be placed parallel on the sides of the chest, at the level of the heart. Be aware that the current may “jump” and be dangerous for team members and not treat the patient effectively Use electrode gel/lube NOT ultrasound gel Paddles should be as close as possible *Defibrillators are dangerous! It is imperative that the individual operating the defibrillator announce “ALL CLEAR” before discharging.*

Prolonged Life Support Post-resuscitation goals Correct underlying cause of arrest Correct problems caused by the arrest and the trauma of the resuscitation

Central Nervous System Support Avoid hypothermia Avoid hypoglycemia or hyperglycemia Perform serial neurological exams: PLR, corneal, palpebral, response to stimuli Neurologic examinations should be done hourly. Pupillary light response, responsiveness to stimulation, respiratory pattern, motor responses, and motor postures should be noted. Normal pupil size and pupillary light responses (PLR) are positive signs. Slow PLRs, anisocoria, and pinpoint pupils that are nonresponsive to light are progressively guarded neurological indicators. Nonresponsive bilaterally dilated pupils indicate severe brain damage and a poor prognosis; recent administration of atropine during the arrest should be ruled out as a cause of dilated nonresponsive pupils. Breathing patterns also reflect brainstem function; abnormal breathing patterns or periods of apnea (breathlessness) are poor prognostic indicators.

Central Nervous System Support Mannitol An osmotic diuretic Sometimes used in the management of cerebral edema and acute renal failure The mannitol molecule resides in the vascular space and draws water from the interstitial spaces between cells, thereby decreasing edema and expanding the vascular volume. As mannitol is excreted by the kidneys, its osmotic effects “pull” water with it into the urine. Mannitol is also a free radical scavenger, which may aid in the treatment of reperfusion injury.

Cardiovascular System Support Monitor heart rate Bradycardia—atropine or glycopyrrolate Sinus tachycardia—may result from fear, anxiety, pain, hypotension, hypoxia Ventricular arrhythmias—check for pulse/heart beat asynchronicity

Cardiovascular System Support Monitor blood pressure Monitor urine production Keep patient on oxygen Acute renal failure is a common complication in the post-arrest patient. Urine production should be closely monitored through a closed urinary catheter if possible. Normal urine output is 1-2 ml/kg/hr. Monitoring central venous pressure, PCV/TP, and body weights can also be an indicator of volume status.

Respiratory System Support Common respiratory complications Pulmonary edema due to congestive heart failure Noncardiogenic edema associated with hypoxia

Respiratory System Support Vigorous chest compressions from CPCR May result in pulmonary contusions, rib fractures, atelectasis, and/or edema Respiratory Therapy Oxygen supplementation Ventilation support Monitoring of arterial blood gases Pulse oximetry and/or capnography Capnography measures ETCO2 – rising values indicate improved pulmonary blood flow and improved perfusion

CPCR Protocols Laboratory markers to monitor(“QATS”) Blood glucose Lactate Packed cell volume Total protein Electrolytes Blood glucose concentrations should be monitored frequently, because many patients who arrest develop hypoglycemia. Patients are typically supplemented with dextrose through IV fluids. Hyperglycemia should be avoided.

Prolonged Life Support Commonly used drugs Furosemide (Lasix) Treats pulmonary edema and acute kidney failure Glucocorticosteroids Controversial May be beneficial in stabilizing cellular membranes Capable of rapid action against the oxygen-free radicals created during reperfusion injury The diuretic effects of furosemide cause an increase in urine output and may enhance the effects of mannitol when given simultaneously. In cases of pulmonary edema, furosemide causes volume contraction, which decreases edema formation. Glucocorticoid examples include dexamethasone sodium phosphate, prednisolone sodium succinate.

Prolonged Life Support Commonly used drugs Dobutamine Positive inotropic drug Improves the contractility of heart muscle Dopamine Increases renal perfusion in canine patients at low doses Increases systemic blood pressure at higher dosages Dobutamine may also be administered to maintain mean arterial pressure. Higher doses are associated with tachycardia; monitor heart rate closely during use. Use of dopamine in feline patients is controversial.

Prolonged Life Support Commonly used drugs Sodium bicarbonate Treatment for severe life-threatening acidosis Adverse effect can outweigh benefits Restore circulation and perfusion before supplementation with fluid therapy Caution is warranted because overzealous bicarbonate therapy is both harmful and easy to accomplish. Unpredictable acid–base disturbances and other problems can be attributed to overdoses. Blood pH must be monitored via serial venous or arterial blood gas analyses.

Prolonged Life Support Commonly used drugs Lidocaine Treatment of ventricular arrhythmias Short acting Contraindicated in ventricular escape and isolated premature ventricular complexes Monitor ECG closely

Prognosis UC Davis study: survival rate at 1 wk for cardiac resuscitation patients: Dogs: 3.8% Cats: 2.3%