Cardiopulmonary cerebral resuscitation.

Cardiopulmonary arrest (CPA) is defined as the abrupt and unexpected cessation of spontaneous and effective ventilation and circulation. CPA can be the natural ending of a normal and long life; however, when CPA is the result of a reversible problem in an animal that has a treatable medical condition, rapid recognition and treatment may make the difference between a happy ending and premature death. Cardiopulmonary resuscitation provides artificial ventilation and circulation until advanced cardiac life support can be provided and spontaneous cardiopulmonary function is restored. The term cardiopulmonary cerebral resuscitation originated in the early 1960s in recognition of the severe central nervous system complications of prolonged cardiac arrest in human beings. Although neurologic complications of CPA may not be as noticeable in companion animals, newer brain-sparing strategies that recognize the consequences of reperfusion injury and the inflammatory cascade may some day offer improved survival.     

Cardiopulmonary resuscitation: current recommendations

Early recognition of CPA is the key to its successful management. For resuscitation to be managed successfully, effective forward blood flow must be established at the onset of the arrest. In our clinical experience, we have found that the Doppler unit allows us to assess the effectiveness of cerebral perfusion better than any other method of blood pressure evaluation. If, by Doppler monitoring results, cerebral perfusion is found to be poor, blood flow may be mechanically improved by instituting high dose epinephrine therapy and interposed abdominal counter-pressure techniques. There is an understandable reluctance on the part of many veterinarians to enter the chest in the course of CPR. Unfortunately, this delay in performing internal compressions is often the reason that open-chest CPR is deemed ineffective by so many practitioners. If external chest CPR is not effective within 1 to 2 min (maximum) of its initiation, an emergency thoracotomy and direct cardiac massage should be performed. We know that perfusion pressure increases three to five times with open versus closed-chest CPR. This improvement in perfusion with direct cardiac massage is due, in part, to the absence of venous pressure elevations created during external chest compression. It follows that better coronary and cerebral blood flow will result in better resuscitation when direct cardiac massage is performed early. The "bottom line" in CPR is successful resuscitation of the patient with resultant good neurologic function. It is hoped that through the use of these techniques and new cytoprotective drugs, the survival rate will rise.     

Cardiopulmonary cerebral resuscitation in neonatal foals

Cardiovascular or pulmonary system failure in neonatal foals requires rapid recognition and initiation of cardiopulmonary cerebral resuscitation (CPCR). Foals may require resuscitation immediately after birth or after arrest from progression of a disease process such as severe sepsis or septic shock. Initial treatment is aimed at establishing an airway and providing ventilation. Circulation is provided by closed-chest compressions. Circulatory access is important to provide intravenous fluid and pharmacologic therapy for cardiovascular support. Ventricular fibrillation and pulseless ventricular tachycardia are arrhythmias not commonly recognized with arrest in foals, whereas asystole and cardiovascular collapse are frequently encountered. Training of personnel, preparation of supplies, and organization during CPCR is essential to a successful outcome.Most of the information used for CPCR in neonatal foals is derived from human medical research and clinical medicine. As new advances are made in human neonatal and pediatric CPCR, many of these treatments and techniques can be applied to foals. This article reviews currently available CPCR guidelines in foals and highlights new perspectives in human medicine that may be applicable to foals.     

Cardiopulmonary resuscitation with vasopressin in a dog

That endogenous vasopressin levels in successfully resuscitated human patients were significantly higher than in patients who died pointed to the possible benefit of administering vasopressin during cardiopulmonary resuscitation (CPR). Several CPR studies in pigs showed that vasopressin improved blood flow to vital organs, cerebral oxygen delivery, resuscitability and neurological outcome when compared with epinephrine. In a small clinical study, vasopressin significantly improved short-term survival when compared with epinephrine indicating its potential as an alternative pressor to epinephrine during CPR in human beings. As there was little clinical data available at that time, its recommended use was limited to adult human beings with shock-refractory ventricular fibrillation. In this report, we present the case of a dog in which the successful management of intraoperative asystolic cardiac arrest involved vasopressin. Unexpected cardiac arrest occurred during anaesthesia for the surgical removal of multiple mammary adenocarcinomata in a 11-year-old Yorkshire terrier. Despite an ASA physical status assignation of III, the dog was successfully resuscitated with external chest compressions, intermittent positive pressure ventilation and vasopressin (2 doses of 0.8 IU kg(-1)) and was discharged 3 days later without signs of neurological injury. We believe vasopressin contributed to restoring spontaneous circulation. It may prove increasingly useful in perioperative resuscitation in dogs.     

Cardiopulmonary resuscitation in small animal medicine: an update

In December 2005, the American Heart Association published new guidelines for cardiopulmonary cerebral resuscitation (CPCR) in humans for the 1st time in 5 years. Many of the recommendations are based on research conducted in animal species and may be applicable to small animal veterinary patients. One important change that may impact how CPCR is performed in veterinary medicine is the recommendation to avoid administration of excessive ventilatory rates because this maneuver severely decreases myocardial and cerebral perfusion, decreasing the chance of survival. The new guidelines also emphasize the importance of providing well-executed, continuous, uninterrupted chest compressions. Interruption of chest compressions should be avoided and, if necessary, should be minimized to <10 seconds. During defibrillation, immediate resumption of chest compressions for 2 minutes after a single shock, before reassessment of the rhythm by ECG, is recommended. This recommendation replaces previous recommendations for the delivery of 3 defibrillatory shocks in rapid succession. Allowing permissive hypothermia postresuscitation has been found to be beneficial and may increase success rate. Medications utilized in cardiopulmonary resuscitation, including amiodarone, atropine, epinephrine, lidocaine, and vasopressin, along with the indications, effects, routes of administration, and dosages, are discussed. The application of the new guidelines to veterinary medicine as well as a review of cardiopulmonary resuscitation in small animals is provided.     

Cardiopulmonary arrest and resuscitation following an extradural injection in a normovolemic dog

Objective – To describe general anesthesia and successful resuscitation of a dog developing asystole and apnea during extradural injection of local anesthetic and an opioid. Case Summary – A Beagle with a ruptured cranial cruciate was premedicated with acepromazine and methadone. Anesthesia was induced with propofol and, after endotracheal intubation, maintained using isoflurane in oxygen. During extradural injection of a mixture of lidocaine, bupivacaine, and morphine the dog developed apnea and asystole. Cardiopulmonary cerebral resuscitation was started promptly and the dog was successfully resuscitated. New Information Provided – Asystole and apnea are possible serious side effects of extradural anesthesia in dogs. With adequate monitoring and early detection successful resuscitation is possible.     

Cardiopulmonary bypass in the cat

OBJECTIVE: To assess the physiologic response to, and acute survival of, cats undergoing cardiopulmonary bypass (CPB) and to evaluate the efficacy of a commercial human pediatric oxygenator system on cats weighing less than 6 kg. STUDY DESIGN: Experimental study. ANIMALS: Six intact male cats METHODS: Cats were placed on cardiopulmonary bypass by cannulating the cranial and caudal vena cavae and the carotid artery. The pediatric CPB circuit was primed with 150 mL of a balanced crystalloid solution. Venous drainage was enhanced by a controlled, vacuum-assist system. A cross-clamp was placed on the ascending aorta and cardiac arrest was induced by antegrade infusion of a cold cardioplegia solution. After 45 minutes of arrest time, the cross-clamp was removed and the cats were weaned off bypass and decannulated. No blood products were administered. Heart rate, mean arterial pressure (MAP), central venous pressure, arterial blood gas, hematocrit (HCT), total plasma protein concentration (TP), serum electrolyte concentrations, and activated clotting time (ACT) were measured at baseline period (BL), during CPB, 60 minutes after CPB (CPB 60) and 90 minutes after CPB (CPB 90). A complete blood count (CBC), blood chemistry profile, and urinalysis were performed at BL, during CPB, and CPB 90. Cats were euthanatized after CPB 90. RESULTS: Cardiopulmonary bypass resulted in a significant (P <.05) decrease in mean HCT (18.0%) and TP (2.3 gm/dL) at CPB 90 when compared to BL (30.5% and 6.0 gm/dL, respectively). The MAP at CPB 90 (54 mm Hg) was decreased from BL (94 mm Hg). The ACT increased from a mean of 124 seconds to > 400 seconds with heparinization and was reversed to 300 seconds with protamine. Mean platelet counts decreased from BL (369,000 /microL) to CPB 90 (94,500 /microL). Mean white blood cell counts decreased from 13,200 /microL at BL to 2,200 /microL at CPB 90. Upon reperfusion, 1 cat fibrillated but was successfully defibrillated. CONCLUSIONS: Cardiopulmonary bypass was performed successfully in 6 cats weighing less than 6 kg. Acute survival to 90 minutes after CPB was achieved in all 6 cats CLINICAL RELEVANCE: The ability to perform CPB in the cat may allow intracardiac repair of various heart defects in this species.     

Cardiopulmonary effects of buprenorphine in horses

OBJECTIVE: To investigate the effects of buprenorphine on cardiopulmonary variables and on abdominal auscultation scores in horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were restrained in stocks and allocated to 2 treatments in a randomized crossover design, with 1-week intervals between each treatment. Saline (0.9% NaCl) solution was administered IV as a control, whereas buprenorphine (10 mug/kg, IV) was administered to the experimental group. Cardiopulmonary data were collected for 120 minutes after buprenorphine or saline solution administration. Abdominal auscultation scores were monitored for 2 and 12 hours after drug administration in the control and experimental groups, respectively. RESULTS: Following control treatment, horses remained calm while restrained in the stocks and no significant changes in cardiopulmonary variables were observed throughout the study. Buprenorphine administration caused excitatory phenomena (restlessness and head shaking). Heart rate, cardiac index, and arterial blood pressure were significantly increased after buprenorphine administration until the end of the observational period (120 minutes). Minimal changes were found in arterial blood gas tensions. Abdominal auscultation scores decreased significantly from baseline for 4 hours after buprenorphine administration. CONCLUSIONS AND CLINICAL RELEVANCE: Buprenorphine induced excitement and hemodynamic stimulation with minimal changes in arterial blood gas tensions. These effects may impact the clinical use of buprenorphine in horses. Further studies are indicated to investigate the effects of buprenorphine on gastrointestinal motility and fecal output.