12. Anesthetic Problems and Emergencies


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  • During surgery the oxygen tank pressure and flowmeter should be checked every 5 minutes. A flowmeter that reads zero indicates the patient is receiving no oxygen. Blockages of the ET tube may be the result of twisting or kinking of the tube; accumulation of material such as blood, mucus, or saliva within the tube; or inappropriate positioning of the tube.
  • Signs of fluid overload in the awake patient may include crackles or wheezes on lung auscultation, serous nasal discharge, bulging eyes, increase in ventilatory rate and/or effort, coughing, vomiting or diarrhea, restlessness, and increased urine output.
  • Colloids include hetastarch, dextran 40 or 70, 10% pentastarch, plasma, or whole blood.
  • Anesthesia can begin when the animal breathes more comfortably.
  • Some of the arrhythmias seen include premature ventricular contractions, atrial fibrillation, ventricular fibrillation, first- and second-degree heart block (normal in the equine species), ventricular tachyarrhythmias, and sinus arrest with escape beats.
  • The principles of emergency care are listed in Procedure 12-1.
  • The action taken by the anesthetist will depend on the cause of the deep anesthesia. Many times the vaporizer setting is too high or the patient was overdosed with injectable agents. Preexisting problems can also be a factor. In analyzing the anesthetic depth, the more factors present the more accurate the evaluation. Procedure 12-2 goes through the steps for treating excessive anesthetic depth.
  • Procedure 12-3 deals with how to handle pale mucous membranes in an anesthetized animal.
  • Procedures 12-4 and 12-5 explain how to handle a prolonged capillary refill time and shock in an anesthetized animal.
  • Procedure 12-6 lists the steps for the treatment of respiratory distress.
  • Procedure 12-7 explains the treatment of tachypnea.
  • Procedure 12-8 explains the treatment for cardiac arrhythmias.
  • See Procedure 12-9 for the steps involved in the treatment of respiratory arrest.
  • With either regurgitation during anesthesia or vomiting, aspirated stomach contents may result in aspiration pneumonia.
  • Seizures should be differentiated from excitement.
  • See Procedure 12-11 for ways to hasten recovery.
  • 12. Anesthetic Problems and Emergencies

    1. 1. Every anesthetic procedure has the potential to cause the death of the animal Anesthetic Problems and Emergencies Chapter 12
    2. 2. Anesthetic Problems and Emergencies: Human Error <ul><li>Failure to get an adequate history and do a physical examination </li></ul><ul><li>Lack of attention to the anesthetic machine and patient </li></ul><ul><li>Inability to recognize early signs of trouble </li></ul><ul><li>Incorrect administration of drugs or administration of incorrect drugs </li></ul><ul><li>Lack of knowledge of pharmacology and improper calculations </li></ul><ul><li>Fatigue and inattentiveness </li></ul>
    3. 3. Anesthetic Problems and Emergencies: Equipment Issues <ul><li>Equipment failure </li></ul><ul><li>Carbon dioxide absorbent exhaustion (rebreathing system) </li></ul><ul><li>Empty oxygen tank </li></ul><ul><li>Incorrect assembly of the anesthetic machine </li></ul><ul><li>Endotracheal tube (ET) blockage </li></ul>
    4. 4. Anesthetic Problems and Emergencies: Equipment Issues (Cont’d) <ul><li>Vaporizer problems </li></ul><ul><ul><li>Using the wrong anesthetic agent </li></ul></ul><ul><ul><li>Tipping the vaporizer </li></ul></ul><ul><ul><li>Vaporizer dial becomes stuck or jammed </li></ul></ul><ul><ul><li>Vaporizer is overfilled </li></ul></ul><ul><ul><li>Two vaporizers used at the same time </li></ul></ul><ul><li>Pop-off valve problems </li></ul><ul><ul><li>Failure to open the pop-off valve </li></ul></ul>
    5. 5. Reduce the Adverse Effects of Anesthetic Agents <ul><li>Choose a protocol suitable for the condition or needs of the patient </li></ul><ul><li>Be familiar with side effects and contraindications for preanesthetic and general anesthesia agents </li></ul><ul><li>Multidrug protocols are safer than single drug protocols </li></ul>
    6. 6. Anesthetic Problems and Emergencies: Patient Factors <ul><li>Geriatric animals </li></ul><ul><ul><li>Have reached 75% of life expectancy </li></ul></ul><ul><ul><li>Decreased heart, lung, and liver function </li></ul></ul><ul><ul><li>Presence of degenerative disorders </li></ul></ul><ul><ul><li>Poor response to stress </li></ul></ul><ul><ul><li>Reduced anesthetic requirements </li></ul></ul><ul><ul><li>Prolonged recovery </li></ul></ul><ul><ul><li>Tendency for hypothermia </li></ul></ul>
    7. 7. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Neonates and pediatric animals are less than 3 months old </li></ul><ul><ul><li>Preoperative fasting </li></ul></ul><ul><ul><li>IV 5% dextrose in lactated Ringers during anesthesia </li></ul></ul><ul><ul><li>Use pediatric microdrip administration set </li></ul></ul><ul><ul><li>Use pediatric or gram scale to weigh animals <5 kg </li></ul></ul><ul><ul><li>Injectable agents may require dilution </li></ul></ul>
    8. 8. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Neonates and pediatric animals </li></ul><ul><ul><li>Have reduced anesthetic requirements </li></ul></ul><ul><ul><li>Neonates have reduced liver and kidney function </li></ul></ul><ul><ul><li>Induction with inhalant agents </li></ul></ul><ul><ul><li>Intubation and catheterization are difficult </li></ul></ul><ul><ul><li>Prone to hypothermia </li></ul></ul>
    9. 9. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Brachycephalic animals </li></ul><ul><ul><li>Anatomic characteristics </li></ul></ul><ul><ul><li>Avoid agents that depress respiration or relax muscles of the pharynx/larynx </li></ul></ul><ul><ul><li>Prone to bradycardia </li></ul></ul><ul><ul><li>Difficult induction period </li></ul></ul><ul><ul><ul><li>Preoxygenate if possible </li></ul></ul></ul><ul><ul><li>Difficult to intubate </li></ul></ul><ul><ul><ul><li>Use laryngoscope and smaller diameter tube </li></ul></ul></ul>
    10. 10. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Brachycephalic animals (Cont’d) </li></ul><ul><ul><li>Use agents that allow rapid recovery </li></ul></ul><ul><ul><li>Monitor closely during recovery for dyspnea </li></ul></ul><ul><ul><li>Recover in an excitement-free or stress-free environment </li></ul></ul><ul><ul><li>Postoperative tranquilizers may be needed </li></ul></ul>
    11. 11. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Sighthounds </li></ul><ul><ul><li>Increased sensitivity to some anesthetic agents </li></ul></ul><ul><li>Obese animals </li></ul><ul><ul><li>Require lower doses of drugs on a per-kilogram basis </li></ul></ul><ul><ul><li>Anesthetic agents are poorly distributed to fat </li></ul></ul><ul><ul><li>Possible respiratory difficulty; preoxygenate </li></ul></ul><ul><ul><li>Shallow, rapid respirations during anesthesia </li></ul></ul>
    12. 12. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Cesarean delivery </li></ul><ul><ul><li>Most often an emergency surgical procedure </li></ul></ul><ul><ul><li>Patient is in compromised condition due to advanced pregnancy </li></ul></ul><ul><ul><li>Patient is not properly prepared for surgery (e.g., not fasted) </li></ul></ul><ul><ul><li>Most anesthetic agents will cross the placenta and affect fetuses </li></ul></ul><ul><ul><li>Patient is at risk for going into shock during surgery </li></ul></ul>
    13. 13. Cesarean Anesthetic Protocols <ul><li>Epidural with tranquilizers or neuroleptanalgesic </li></ul><ul><ul><li>IV fluids and oxygen also administered </li></ul></ul><ul><ul><li>Monitor blood pressure </li></ul></ul><ul><li>General anesthesia with injectable or inhalant agents </li></ul><ul><ul><li>Preoxygenation is helpful </li></ul></ul><ul><ul><li>Propofol or ketamine </li></ul></ul><ul><li>Opioid agents </li></ul><ul><ul><li>Reversible in both mother and neonate </li></ul></ul>
    14. 14. Anesthetic Concerns for Cesarean Patients <ul><li>Hypoxemia </li></ul><ul><li>Hypercarbia </li></ul><ul><li>Hypotension </li></ul><ul><li>Physiological anemia </li></ul><ul><li>Acid/base imbalance </li></ul><ul><li>Tissue trauma </li></ul><ul><li>Cardiac arrhythmias </li></ul>
    15. 15. Care of Puppies and Kittens Delivered by Cesarean Section <ul><li>Respiratory function </li></ul><ul><ul><li>Deliver oxygen by facemask </li></ul></ul><ul><ul><li>Intubate with 16- or 18-gauge IV catheter and gently bag every 5 seconds </li></ul></ul><ul><ul><li>Aspirate fluid from the mouth and nose with eyedropper or bulb syringe </li></ul></ul><ul><ul><li>Administer reversal agents, doxapram, and/or dilute atropine as needed </li></ul></ul>
    16. 16. Care of Puppies and Kittens Delivered by Cesarean Section (Cont’d) <ul><li>Cardiac function </li></ul><ul><ul><li>Gentle cardiac massage </li></ul></ul><ul><ul><li>Deliver oxygen by facemask </li></ul></ul><ul><li>Allow to nurse as soon as mother is recovered </li></ul><ul><ul><li>Watch neonates if mother is still groggy </li></ul></ul><ul><ul><li>Anesthetic agents secreted in milk don’t affect neonates </li></ul></ul>
    17. 17. Anesthetic Problems and Emergencies: Patient Factors <ul><li>Recent trauma that requires emergency attention </li></ul><ul><ul><li>Trauma ailments increase anesthetic risk </li></ul></ul><ul><li>Respiratory difficulties </li></ul><ul><ul><li>May result from pneumothorax, pulmonary contusions, hemorrhage, or diaphragmatic hernia </li></ul></ul><ul><ul><li>Decreases the V T of the patient leading to decreased oxygenation </li></ul></ul><ul><ul><li>Increased CO 2 levels leading to acid/base imbalance and cardiac arrhythmias </li></ul></ul><ul><ul><li>Loss of blood or fluid sequestration changes blood pressure </li></ul></ul>
    18. 18. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Change in blood pressure </li></ul><ul><ul><li>Resulting from a change in cardiac output or vascular tone </li></ul></ul><ul><ul><li>Anesthetic depth will affect both parameters </li></ul></ul><ul><ul><li>Hypotension -> decreased tissue perfusion -> tissue hypoxia/anoxia -> anaerobic glycolysis -> lactic acid production -> acid/base imbalance </li></ul></ul><ul><ul><li>Monitor blood pressure closely </li></ul></ul><ul><ul><ul><li>Doppler or oscillometric methods </li></ul></ul></ul><ul><ul><ul><li>Digital pulse palpation </li></ul></ul></ul><ul><ul><ul><li>Capillary refill time </li></ul></ul></ul>
    19. 19. Fluid Therapy for Hypotension <ul><li>Crystalloid fluid administration </li></ul><ul><ul><li>May have to deliver small boluses for rapid therapy </li></ul></ul><ul><ul><li>Crystalloid fluids stay in intravascular space <2 hours </li></ul></ul><ul><ul><li>Watch for fluid overload, especially in cats </li></ul></ul><ul><ul><li>Monitor heart rate, blood pressure, mucous membrane color, and capillary refill time </li></ul></ul>
    20. 20. Fluid Therapy for Hypotension (Cont’d) <ul><li>Colloid fluid administration </li></ul><ul><ul><li>Helpful if blood pressure can’t be maintained </li></ul></ul><ul><ul><li>Remain in the intravascular space longer than crystalloids </li></ul></ul><ul><ul><li>Will increase colloidal osmotic pressure and help stabilize blood pressure </li></ul></ul><ul><ul><li>Given in smaller volume in conjunction with crystalloids </li></ul></ul>
    21. 21. Anesthetic Problems and Emergencies: Patient Factors <ul><li>Respiratory problems in the trauma patient </li></ul><ul><ul><li>Direct trauma to the chest leading to lung collapse or failure of alveolar gas exchange </li></ul></ul><ul><ul><li>Must remove air/fluid from chest cavity prior to anesthesia </li></ul></ul><ul><ul><li>Deliver supplemental oxygen </li></ul></ul><ul><li>Oxygen delivery methods </li></ul><ul><ul><li>Flow-by-oxygen </li></ul></ul><ul><ul><li>Nasal catheters </li></ul></ul><ul><ul><li>Oxygen collars </li></ul></ul>
    22. 22. Oxygen Delivery Methods
    23. 23. Thoracocentesis (Chest Tap) <ul><li>To relieve pneumothorax or pleural effusion from chest cavity </li></ul><ul><li>Performed by veterinarian Prepped by veterinary technician </li></ul><ul><ul><li>Temporary bandage over chest wound </li></ul></ul><ul><ul><li>Place animal in sternal recumbency or standing position </li></ul></ul><ul><ul><li>Shave lateral chest wall between the 7th and 9th intercostal spaces caudal to point of the elbow </li></ul></ul><ul><ul><li>Aseptically prepare 4 cm × 4 cm area </li></ul></ul><ul><ul><li>Prepare a 20- to 22-gauge, 1- to 1½-inch catheter with a three-way stopcock and large syringe </li></ul></ul>
    24. 24. Other Considerations for the Trauma Patient <ul><li>Cardiac arrhythmias </li></ul><ul><ul><li>Common 12-72 hours after trauma </li></ul></ul><ul><ul><li>Electrocardiograms </li></ul></ul><ul><li>Shock: especially where hemorrhage is significant </li></ul><ul><li>Internal injuries: fractures or ruptured organs </li></ul><ul><li>Anesthesia </li></ul><ul><ul><li>Best to delay it until the animal is stabilized </li></ul></ul><ul><ul><li>Delay allows more thorough patient workup including thoracic radiographs </li></ul></ul>
    25. 25. Anesthetic Problems and Emergencies: Patient Factors <ul><li>Preexisting cardiovascular disease </li></ul><ul><ul><li>Anemia </li></ul></ul><ul><ul><li>Shock </li></ul></ul><ul><ul><li>Cardiomyopathy (primary or secondary) </li></ul></ul><ul><ul><li>Congestive heart disease (mitral valve insufficiency) </li></ul></ul><ul><ul><li>Heartworm disease </li></ul></ul><ul><ul><li>Coexisting imbalances (e.g., hypoxia, hypercapnia, electrolyte imbalances) </li></ul></ul>
    26. 26. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Bradycardia </li></ul><ul><ul><li>Most common cardiac anesthetic problem </li></ul></ul><ul><ul><li>Caused by preanesthetic or anesthetic drugs </li></ul></ul><ul><ul><li>Force of cardiac contraction may also be decreased </li></ul></ul><ul><ul><li>Blood return to the heart may be decreased (preload) </li></ul></ul><ul><ul><li>Treat with drugs or adjustment of anesthetic depth </li></ul></ul>
    27. 27. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Cardiac arrhythmias </li></ul><ul><ul><li>Caused by anoxia/hypercarbia, poor tissue perfusion, acid/base imbalance, myocardial damage </li></ul></ul><ul><ul><li>Difficult to detect on physical examination; may find dropped beats </li></ul></ul><ul><ul><li>Diagnose with ECG and report immediately to veterinarian who will determine the treatment required </li></ul></ul><ul><ul><li>Concurrent pulmonary disease is sometimes seen </li></ul></ul>
    28. 28. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Anesthetic considerations </li></ul><ul><ul><li>Stabilize patient as per veterinarian’s instructions </li></ul></ul><ul><ul><li>Preoxygenate with facemask 5 minutes prior to induction </li></ul></ul><ul><ul><li>Increased risk of overhydration with IV fluid </li></ul></ul><ul><ul><ul><li>Monitor for pulmonary edema </li></ul></ul></ul>
    29. 29. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Respiratory disease </li></ul><ul><ul><li>Caused by: </li></ul></ul><ul><ul><li>Pleural effusion Diaphragmatic hernia </li></ul></ul><ul><ul><li>Pneumothorax Pneumonia </li></ul></ul><ul><ul><li>Tracheal collapse Pulmonary edema </li></ul></ul><ul><ul><li>Clinical signs </li></ul></ul><ul><ul><ul><li>Tachypnea </li></ul></ul></ul><ul><ul><ul><li>Dyspnea </li></ul></ul></ul><ul><ul><ul><li>Cyanosis </li></ul></ul></ul>
    30. 30. <ul><li>Anesthetic considerations </li></ul><ul><ul><li>V T is reduced and respiratory rate is decreased in most anesthetized animals </li></ul></ul><ul><ul><li>A decrease in V T will result in a decreased alveolar gas exchange </li></ul></ul><ul><ul><li>Lighten anesthesia as much as possible in a patient with respiratory disease </li></ul></ul><ul><ul><li>Provide intermittent ventilation </li></ul></ul><ul><ul><li>Evaluate oxygen-carrying capacity with PCV or pulse oximeter </li></ul></ul><ul><ul><li>Preoxygenation is necessary prior to induction </li></ul></ul>Anesthetic Problems and Emergencies: Patient Factors (Cont’d)
    31. 31. Respiratory Problems During Anesthesia <ul><li>Clinical signs: dyspnea or cyanosis </li></ul><ul><li>Assessment </li></ul><ul><ul><li>Respiratory character and volume </li></ul></ul><ul><ul><li>Depth of anesthesia </li></ul></ul><ul><ul><li>Associated with pain </li></ul></ul><ul><ul><li>Proper ET tube placement </li></ul></ul><ul><ul><li>ET tube blockage </li></ul></ul><ul><ul><li>Oxygen saturation </li></ul></ul><ul><ul><li>Arterial or end-tidal CO 2 </li></ul></ul>
    32. 32. Respiratory Problems During Anesthesia (Cont’d) <ul><li>Actions </li></ul><ul><ul><li>Intermittent positive-pressure ventilation </li></ul></ul><ul><ul><li>Reintubate if necessary </li></ul></ul><ul><ul><li>Radiographs and thoracocentesis </li></ul></ul>
    33. 33. Anesthetic Problems and Emergencies: Patient Factors <ul><li>Diaphragmatic hernia </li></ul><ul><ul><li>Preoxygenate for 5-10 minutes prior to induction </li></ul></ul><ul><ul><li>Avoid head-down patient positions before and during anesthesia </li></ul></ul><ul><ul><li>Rapid intubation </li></ul></ul><ul><ul><li>Ventilatory assistance or ventilator if necessary </li></ul></ul><ul><ul><li>Postoperative observation for signs of respiratory distress </li></ul></ul>
    34. 34. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Hepatic disease </li></ul><ul><ul><li>Liver necessary for drug metabolism, blood clotting factors, plasma proteins, carbohydrate metabolism </li></ul></ul><ul><ul><li>Preanesthetic agents must be chosen with care </li></ul></ul>
    35. 35. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Renal disease </li></ul><ul><ul><li>Kidneys maintain volume and electrolyte composition of body fluids </li></ul></ul><ul><ul><li>Renal excretion removes anesthetic agents and metabolites from the body </li></ul></ul><ul><ul><li>General anesthesia is associated with decreased blood flow to the kidneys </li></ul></ul><ul><ul><li>Diagnosis: urine specific gravity, BUN, creatinine </li></ul></ul><ul><ul><li>Offer water up to 1 hour prior to premedication </li></ul></ul><ul><ul><li>Correct dehydration prior to anesthesia </li></ul></ul>
    36. 36. Anesthetic Problems and Emergencies: Patient Factors (Cont’d) <ul><li>Urinary blockage </li></ul><ul><ul><li>Clinical signs </li></ul></ul><ul><ul><ul><li>Depression </li></ul></ul></ul><ul><ul><ul><li>Dehydration </li></ul></ul></ul><ul><ul><ul><li>Uremia </li></ul></ul></ul><ul><ul><ul><li>Acidosis </li></ul></ul></ul><ul><ul><ul><li>Hyperkalemia (can lead to cardiac arrest) </li></ul></ul></ul><ul><ul><li>Inhalation agents are less hazardous for the patient </li></ul></ul>
    37. 37. Anesthetic Problems and Emergencies <ul><li>Animals won’t stay anesthetized </li></ul><ul><ul><li>Check vaporizer setting </li></ul></ul><ul><ul><li>Check level of anesthetic in the vaporizer </li></ul></ul><ul><ul><li>Proper ET tube placement or air leakage around it </li></ul></ul><ul><ul><li>Patient apnea </li></ul></ul><ul><ul><li>Shallow respirations </li></ul></ul><ul><ul><li>Proper assembly of anesthetic machine with tight connections </li></ul></ul><ul><ul><li>Adequate oxygen flow </li></ul></ul><ul><ul><li>Anesthetic machine/vaporizer is working properly </li></ul></ul><ul><ul><li>Agonal breathing vs. light plane breathing </li></ul></ul>
    38. 38. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Animals are too deeply anesthetized </li></ul><ul><ul><li><6 bpm; shallow respirations, dyspnea </li></ul></ul><ul><ul><li>Pale/cyanotic mucous membranes </li></ul></ul><ul><ul><li>Capillary refill time >2 seconds </li></ul></ul><ul><ul><li>Bradycardia </li></ul></ul><ul><ul><li>Weak pulse; systolic blood pressure <80 mm Hg </li></ul></ul><ul><ul><li>Cardiac arrhythmias; irregular QRS complexes or VPCs </li></ul></ul><ul><ul><li>Hypothermia </li></ul></ul><ul><ul><li>Absent reflexes </li></ul></ul><ul><ul><li>Flaccid muscle tone </li></ul></ul><ul><ul><li>Dilated pupils </li></ul></ul>
    39. 39. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Pale mucous membranes </li></ul><ul><ul><li>Preexisting conditions </li></ul></ul><ul><ul><li>Blood loss during surgery </li></ul></ul><ul><ul><li>Anesthetic agent that causes vasodilation and hypotension </li></ul></ul><ul><ul><li>Hypothermia </li></ul></ul><ul><ul><li>Pain </li></ul></ul>
    40. 40. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Prolonged capillary refill time (>2 seconds) </li></ul><ul><ul><li>Blood pressure cannot adequately perfuse superficial tissues </li></ul></ul><ul><ul><li>May result from conditions present prior to induction </li></ul></ul><ul><ul><li>May be secondary to blood loss during surgery </li></ul></ul><ul><ul><li>May be seen in animals in deep anesthesia </li></ul></ul>
    41. 41. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Respiratory distress </li></ul><ul><ul><li>Dyspnea </li></ul></ul><ul><ul><ul><li>Patient is unable to obtain sufficient oxygen or remove adequate CO 2 </li></ul></ul></ul><ul><ul><li>Cyanosis </li></ul></ul><ul><ul><ul><li>Oxygenation is inadequate </li></ul></ul></ul>
    42. 42. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Sources of respiratory distress during anesthesia </li></ul><ul><ul><li>Empty oxygen tank </li></ul></ul><ul><ul><li>Flowmeter is turned off </li></ul></ul><ul><ul><li>Anesthetic circuit or ET tube is blocked </li></ul></ul><ul><ul><li>Airway obstruction or respiratory pathology </li></ul></ul><ul><ul><li>Deep anesthesia </li></ul></ul>
    43. 43. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Tachypnea </li></ul><ul><ul><li>Rapid respirations as opposed to dyspnea </li></ul></ul><ul><ul><li>Commonly seen with opioid use </li></ul></ul><ul><ul><li>Associated with light anesthesia accompanied by tachycardia and spontaneous movement </li></ul></ul><ul><ul><li>May be seen in hyperthermic animals </li></ul></ul>
    44. 44. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Abnormalities in cardiac rate and rhythm seen in anesthetized animals </li></ul><ul><ul><li>Tachypnea </li></ul></ul><ul><ul><ul><li>May result from drugs, preexisting conditions, or surgical stimulation </li></ul></ul></ul><ul><ul><ul><li>May not require treatment </li></ul></ul></ul><ul><ul><ul><li>Check vaporizer setting and anesthetic depth </li></ul></ul></ul>
    45. 45. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Abnormalities in cardiac rate and rhythm are seen in anesthetized animals </li></ul><ul><ul><li>Bradycardia </li></ul></ul><ul><ul><ul><li>May be secondary to drug administration, vagal stimulation, deep anesthesia, or physiologic imbalances </li></ul></ul></ul><ul><ul><ul><li>May not require treatment </li></ul></ul></ul><ul><ul><ul><li>Check vaporizer setting, bag with 100% oxygen, or administer reversal drugs </li></ul></ul></ul><ul><ul><li>Cardiac arrhythmias </li></ul></ul><ul><ul><ul><li>May result from drugs and will have a short duration </li></ul></ul></ul><ul><ul><ul><li>May be a problem in geriatric patients or patients with preexisting conditions </li></ul></ul></ul><ul><ul><ul><li>Common during induction and light anesthesia </li></ul></ul></ul>
    46. 46. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Respiratory arrest </li></ul><ul><ul><li>Cessation of respiratory efforts </li></ul></ul><ul><ul><li>Can lead to cardiac arrest </li></ul></ul><ul><ul><li>Temporary arrest </li></ul></ul><ul><ul><ul><li>May follow injection of respiratory depressants or following a period of prolonged bagging </li></ul></ul></ul><ul><ul><ul><li>Check other vital signs for abnormalities </li></ul></ul></ul>
    47. 47. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Respiratory arrest (Cont’d) </li></ul><ul><ul><li>True arrest </li></ul></ul><ul><ul><ul><li>Requires immediate action </li></ul></ul></ul><ul><ul><ul><li>Can result from anesthetic overdose, cessation of oxygen flow, or preexisting respiratory disease </li></ul></ul></ul><ul><ul><ul><li>May be preceded by dyspnea or cyanosis and abnormal vital signs </li></ul></ul></ul><ul><ul><ul><li>May use Ambu bag, mouth-to-ET tube, or mouth-to-muzzle resuscitation </li></ul></ul></ul>
    48. 48. Use of an Ambu Bag
    49. 49. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Cardiac arrest </li></ul><ul><ul><li>No heartbeat is auscultated or palpated </li></ul></ul><ul><ul><li>Normal QRS complexes are absent </li></ul></ul><ul><ul><li>No arterial pulse and blood pressure <25 mm Hg </li></ul></ul><ul><ul><li>Gray or cyanotic mucous membranes </li></ul></ul><ul><ul><li>Widely dilated pupils, no corneal reflex </li></ul></ul><ul><ul><li>Agonal breathing </li></ul></ul><ul><li>Some prior warning is usually present </li></ul><ul><ul><li>Respiratory distress or arrest, cyanosis/dyspnea, prolonged capillary refill time, arrhythmia </li></ul></ul>
    50. 50. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Cardiopulmonary cerebrovascular resuscitation (CPCR) started immediately after cardiac arrest </li></ul><ul><ul><li>Five people (ideal) involved </li></ul></ul><ul><ul><ul><li>1 performs chest compressions </li></ul></ul></ul><ul><ul><ul><li>2 bags the animal </li></ul></ul></ul><ul><ul><ul><li>3 assesses the pulse during compressions and checks the pulse or ECG when compressions are stopped </li></ul></ul></ul><ul><ul><ul><li>4 draws up and administers drugs as per the veterinarian’s instructions </li></ul></ul></ul><ul><ul><ul><li>5 maintains a record of the patient’s status and resuscitative treatment </li></ul></ul></ul>
    51. 51. Anesthetic Problems and Emergencies (Cont’d) <ul><li>Cardiac arrest with CPCR </li></ul><ul><ul><li>A = airway </li></ul></ul><ul><ul><li>B = breathing </li></ul></ul><ul><ul><li>C = circulation </li></ul></ul><ul><ul><li>D = drugs </li></ul></ul><ul><ul><li>E = ECG </li></ul></ul><ul><li>Circulation is the most important step so the correct order is CABDE </li></ul>
    52. 52. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) <ul><li>Circulation </li></ul><ul><ul><li>Most important factor is return of spontaneous circulation (ROSC) </li></ul></ul><ul><ul><li>Cardiac compressions </li></ul></ul><ul><ul><ul><li>Method depends on the size of the animal </li></ul></ul></ul><ul><ul><ul><li>Compress chest about 1/3 the diameter of the chest wall </li></ul></ul></ul><ul><ul><ul><li>1-2 compressions/second generates 100 bpm heart rate </li></ul></ul></ul><ul><ul><ul><li>Compressions manually force blood through the heart and into tissues </li></ul></ul></ul><ul><ul><ul><li>Each compression should produce a palpable femoral pulse </li></ul></ul></ul>
    53. 53. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) (Cont’d) <ul><li>Circulation (Cont’d) </li></ul><ul><ul><li>Bag the patient every 10-12 seconds </li></ul></ul><ul><ul><ul><li>Simultaneously with compressions </li></ul></ul></ul><ul><ul><li>Some results should be seen within 2 minutes </li></ul></ul><ul><ul><li>Internal compressions may be necessary </li></ul></ul><ul><ul><li>Resuscitation is unlikely to be successful after 15 minutes </li></ul></ul><ul><ul><li>Once spontaneous cardiac contractions are established, continue bagging until spontaneous breathing is established (several hours) </li></ul></ul>
    54. 54. Cardiac Compressions
    55. 55. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) (Cont’d) <ul><li>Airway and breathing </li></ul><ul><ul><li>Intubate immediately if not already intubated </li></ul></ul><ul><ul><li>Turn off vaporizer and nitrous oxide </li></ul></ul><ul><ul><ul><li>Animal should breathe 100% oxygen </li></ul></ul></ul><ul><ul><li>One breath every 10-12 seconds </li></ul></ul><ul><ul><li>Chest should rise slightly during bagging </li></ul></ul>
    56. 56. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) (Cont’d) <ul><li>Drugs </li></ul><ul><ul><li>Veterinarian authorizes dosage, route, and nature of drugs </li></ul></ul><ul><ul><li>Catheterized animals </li></ul></ul><ul><ul><ul><li>Drugs administered IV followed by rapid fluid administration </li></ul></ul></ul><ul><ul><ul><li>Be careful of overhydration </li></ul></ul></ul><ul><ul><li>Injections into the base of the tongue or by the intratracheal route are the second choice </li></ul></ul><ul><ul><li>Intracardiac injections should be avoided </li></ul></ul>
    57. 57. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) (Cont’d) <ul><li>Commonly used drugs </li></ul><ul><ul><li>Epinephrine </li></ul></ul><ul><ul><ul><li>Cardiac arrest </li></ul></ul></ul><ul><ul><li>Vasopressin </li></ul></ul><ul><ul><ul><li>In place of or alternated with epinephrine </li></ul></ul></ul><ul><ul><li>Atropine </li></ul></ul><ul><ul><ul><li>Anesthesia-related cardiac arrest </li></ul></ul></ul><ul><ul><li>Dopamine or dobutamine </li></ul></ul><ul><ul><ul><li>Increase force and rate of cardiac contractions </li></ul></ul></ul>
    58. 58. Cardiopulmonary Cerebrovascular Resuscitation (CPCR) (Cont’d) <ul><li>ECG </li></ul><ul><ul><li>Don’t use alcohol if a defibrillator is present </li></ul></ul><ul><ul><li>Asystole </li></ul></ul><ul><ul><ul><li>No electrical activity </li></ul></ul></ul><ul><ul><li>Ventricular fibrillation </li></ul></ul><ul><ul><ul><li>Coarse vertical zig-zag lines resulting from disorganized muscular heart activity </li></ul></ul></ul><ul><ul><li>Pulseless electrical activity (electromechanical dissociation, EMD) </li></ul></ul><ul><ul><ul><li>Normal or near-normal complexes </li></ul></ul></ul>
    59. 59. Pulseless Electrical Activity
    60. 60. ROSC Aftercare <ul><li>Monitor cardiovascular and respiratory function </li></ul><ul><ul><li>Blood pressure, blood gases, pulse oximetry, ECG, capnography </li></ul></ul><ul><li>Drug and fluid therapy varies </li></ul><ul><li>Assess brain function </li></ul><ul><li>Repeat arrest within 24 hours is common </li></ul><ul><li>Following successful ROSC, other conditions may arise </li></ul><ul><ul><li>Pulmonary or cerebral edema </li></ul></ul>
    61. 61. Potential Problems During the Recovery Period <ul><li>Regurgitation during anesthesia </li></ul><ul><ul><li>A passive process under anesthesia </li></ul></ul><ul><ul><ul><li>No retching, just fluid draining from animal’s mouth or nose </li></ul></ul></ul><ul><ul><li>Stomach contents may be aspirated into respiratory tract </li></ul></ul><ul><ul><li>Most common occurrence in head-down surgical positions and in ruminants </li></ul></ul><ul><ul><li>Treatment </li></ul></ul><ul><ul><ul><li>Immediate placement of cuffed ET tube </li></ul></ul></ul><ul><ul><ul><li>Clean out regurgitated material with suction </li></ul></ul></ul>
    62. 62. Potential Problems During the Recovery Period (Cont’d) <ul><li>Vomiting during or after anesthesia </li></ul><ul><ul><li>Common in brachycephalic dogs or nonfasted animals </li></ul></ul><ul><ul><li>An active process usually accompanied by retching </li></ul></ul><ul><ul><li>Usually occurs as the animal is losing or regaining consciousness </li></ul></ul><ul><ul><li>Signs </li></ul></ul><ul><ul><ul><li>Airway obstruction leading to dyspnea/cyanosis, bronchospasm </li></ul></ul></ul><ul><ul><li>Treatment </li></ul></ul><ul><ul><ul><li>Intubation and suction if unconscious </li></ul></ul></ul><ul><ul><ul><li>Lower head and clean oral cavity if conscious </li></ul></ul></ul>
    63. 63. Potential Problems During the Recovery Period (Cont’d) <ul><li>Seizures </li></ul><ul><ul><li>Seen with ketamine administration, after diagnostic procedures (myelography), or preexisting conditions </li></ul></ul><ul><ul><li>Signs </li></ul></ul><ul><ul><ul><li>Spontaneous twitching; uncontrolled movements of head, neck, and limbs; opisthotonus; triggered by a stimulus </li></ul></ul></ul><ul><ul><li>Treatment </li></ul></ul><ul><ul><ul><li>Reduce stimuli, postoperative analgesia, diazepam or propofol, monitor for hyperthermia </li></ul></ul></ul>
    64. 64. Potential Problems During the Recovery Period (Cont’d) <ul><li>Excitement </li></ul><ul><ul><li>Seen after barbiturate anesthesia or high opioid doses, as spontaneous paddling and vocalization </li></ul></ul><ul><ul><li>Treatment may not be necessary </li></ul></ul><ul><ul><ul><li>Sedatives may help </li></ul></ul></ul><ul><ul><ul><li>Naloxone can reverse opioids </li></ul></ul></ul><ul><li>Seizures should be differentiated from excitement </li></ul>
    65. 65. Potential Problems During the Recovery Period (Cont’d) <ul><li>Dyspnea in cats </li></ul><ul><ul><li>Dyspnea is usually caused by laryngospasm sometimes triggered by removal of the ET tube </li></ul></ul><ul><ul><li>Laryngeal edema may result from repeated intubation attempts </li></ul></ul><ul><ul><li>May breathe with an audible stertor (wheeze) during inspiration </li></ul></ul><ul><ul><li>Differentiate from growling during expiration </li></ul></ul><ul><ul><li>May resolve itself or may need oxygen administration via facemask, intubation, or a tracheotomy </li></ul></ul><ul><ul><li>Is easier to prevent than treat </li></ul></ul>
    66. 66. Potential Problems During the Recovery Period (Cont’d) <ul><li>Dyspnea in dogs </li></ul><ul><ul><li>Breed-related </li></ul></ul><ul><ul><ul><li>Brachycephalic dogs </li></ul></ul></ul><ul><ul><li>Airway obstruction </li></ul></ul><ul><ul><ul><li>Anatomy, foreign objects, postsurgical tissue swelling </li></ul></ul></ul><ul><ul><li>Humidified oxygen can be delivered to an awake animal </li></ul></ul><ul><ul><ul><li>By facemask, nasal cannula, E-collar, or oxygen cage/tent </li></ul></ul></ul>
    67. 67. Potential Problems During the Recovery Period (Cont’d) <ul><li>Causes of prolonged recovery </li></ul><ul><ul><li>Impaired renal or hepatic function </li></ul></ul><ul><ul><li>Hypothermia </li></ul></ul><ul><ul><li>Patient susceptibility to anesthetic agent </li></ul></ul><ul><ul><li>Breed variation </li></ul></ul><ul><ul><li>Coexisting disorder </li></ul></ul><ul><ul><li>Prolonged anesthesia or deep anesthesia </li></ul></ul>