Cardiopulmonary Resuscitation In Dogs Research Articles

Retrospective study of gross and histopathologic lesions associated with closed chest cardiopulmonary resuscitation in dogs.

To investigate and characterise the incidence of iatrogenic complications secondary to closed chest cardiopulmonary resuscitation in dogs. Necropsy reports and histologic sections of tissues were retrospectively examined from 180 dogs that had received closed chest cardiopulmonary resuscitation to determine lesions associated with resuscitation. The most common complication was pulmonary haemorrhage (81/163, 49.7%, 95% confidence interval: 42.1 to 57.3), although only nine dogs had pulmonary haemorrhage of at least moderate severity. Liver fractures occurred in 16 of 180 cases (8.9%, 95% confidence interval: 5.5 to 14.0). Blood loss of >15% of blood volume into the abdomen and/or thorax occurred in 13 of 180 cases (7.2%, 95% confidence interval: 4.2 to 12.1). Significant haemorrhage secondary to cardiopulmonary resuscitation may decrease the chances of achieving the return of spontaneous circulation or may cause or compound ischemic damage to critical organs if the return of spontaneous circulation is achieved. Following successful cardiopulmonary resuscitation, animals should be screened for cavitary or pulmonary haemorrhage, as significant haemorrhage could be a factor in recurrence of cardiac arrest.

Comparison of left fourth and fifth intercostal space thoracotomy for open-chest cardiopulmonary resuscitation in dogs.

ObjectiveTo determine whether ease of access to thoracic structures for performing open‐chest cardiopulmonary resuscitation (OC‐CPR) differed between fourth and fifth intercostal space (ICS) left lateral thoracotomies in dogs, and to determine if “shingling” improved access for OC‐CPR manipulations.DesignProspective single‐blinded study.SettingLaboratory.AnimalsTwelve mixed breed canine cadavers weighing approximately 20 kg.InterventionsLeft lateral thoracotomies were performed at the 4th ICS (n = 6) or 5th ICS (n = 6). Shingling at the 4th or 5th ICS, as applicable, was performed after initial data collection and outcomes were reassessed.Measurements and main resultsThree evaluators blinded to the surgical approach scored the following parameters on a 0 to 10 scale (0 = easiest, 10 = most difficult): ease of access of the phrenicopericardial ligament, ease of pericardial incision, ease of appropriate hand position, ease of aortic access, ease of Rumel tourniquet application, and ease of proper placement of defibrillation paddles. Objective measurements (time to completion or number of attempts) were made for all but ease of pericardial incision and ease of appropriate hand position. Outcomes were reassessed after shingling.The 5th ICS was superior for ease of aortic access (P = 0.042), time to visualization of aorta (P = 0.009), and ease of application of a Rumel tourniquet (P = 0.019). When comparing scores pre‐ and post‐shingling, shingling improved time to visualization of the aorta (P < 0.001), time to placement of Rumel tourniquet (P < 0.001), ease of paddle placement (P = 0.017), and time to paddle placement (P < 0.001).ConclusionsEither 4th or 5th ICS thoracotomy may provide adequate access to intrathoracic structures pertinent to performing OC‐CPR in dogs weighing approximately 20 kg, but 5th ICS was preferred for most manipulations, and shingling improved access for most of the measured parameters.

Small animal cardiopulmonary -resuscitation (CPR) in general practice

Cardiopulmonary arrest (CPA) is the acute cessation of systemic perfusion and ventilation. It leads to a lack of tissue oxygen delivery and, if not addressed quickly, will inevitably cause death. Cardiopulmonary resuscitation (CPR) is the only available treatment for CPA and several opportunities exist to improve the veterinary team's resuscitation approach and optimize small animal CPR patient outcomes. In 2012, the Reassessment Campaign on Veterinary Resuscitation (RECOVER) initiative generated evidence-based clinical guidelines to form the basis for training and practice of CPR in dogs and cats. When employing an evidence-based, standardized approach to small animal CPR, return of spontaneous circulation can be achieved in up to 58% of patients and up to 7% of dogs and 19% of cats can be discharged from the veterinary hospital alive. Survival for dogs and cats that suffer CPA is best in patients that suffer a peri-anesthetic arrest, so high quality CPR in the anesthesia patient population is of utmost importance and expected to be the most rewarding. To ensure the best possible outcomes for any patient suffering from CPA and undergoing CPR, a comprehensive resuscitation strategy is necessary, that includes preventive and preparedness measures, basic life support (chest compressions and ventilation), advanced life support (optimization of the patient status by targeted drug therapy, cardiac rhythm monitoring, and defibrillation), and post-cardiac arrest critical care. This article summarizes the most important RECOVER CPR guidelines for the small animal practitioner.

Confecção de modelo de baixo custo para treinamento de ressuscitação cardiopulmonar em cão

Cardiopulmonary resuscitation (CPR) should be started promptly in a situation of cardiorespiratory arrest (CRP). The Reassessment Campaign on Veterinary Resuscitation (RECOVER) proposes clinical recommendations for the application of the procedure in dogs and cats and also recognizes the need for cognitive and psychomotor skills to perform the entire protocol in an agile and efficient manner. In this way, an ideal training should cover didactic components and practice of manual skills, with the use of discriminated models and simulators. The use of alternative methods with synthetic models is supported by the increase in concerns about animal welfare, a demand that is presented by Veterinary Medicine scholars and residents of the Veterinary Hospital of the Federal University of Paraná (UFPR). In addition to the high cost of commercially available models, the objective of this work is to present a low-cost model for training CPR in dogs. After acquisition of a plush dog, a representative structure of the internal part of the chest was elaborated with a plastic packaging of powdered chocolate filled with silicon fiber. Then, the larynx cartilages were produced in silicone rubber of medium flexibility, adhered to a corrugated trachea. The molds of the hard palate and upper and lower dental arches were made of resin, painted with acrylic paint and fixed to a modified dental articulator. For the oral mucosa and tongue it was made low viscosity silicone elastomer structures. The model allowed to perform the procedures of thoracic compression and endotracheal intubation, steps included in the CPR. The model was tested by Veterinary Medicine professionals with experience in CPR, and a good result was reported. The presented CPR model allowed the simulation of the basic support to life and, being of low cost, can be made by other educational institutions with this same purpose.

Efficacy of Manual Ventilation Techniques During Cardiopulmonary Resuscitation in Dogs.

The efficacy of ventilation of dogs during cardiopulmonary resuscitation (CPR) with a tight fitting face mask or mouth-to-nose rescue breathing has not been evaluated. Twenty-four purpose bred research dogs: Dogs were randomized to be ventilated by cuffed orotracheal tube, tight fitting face mask, mouth-to-nose breathing or compressions only during CPR (n = 6 in all groups). Orotracheal tube and face mask ventilation was performed on room air. Chest compressions were performed during the experimental procedure. Arterial blood gases were performed prior to euthanasia (baseline), at 3 min and at 6 min of CPR. PaO2 and PaCO2 were compared for each time point and each group. There was no difference in PaO2 or PaCO2 between groups at baseline. At 6 min all groups had a significantly higher PaCO2 (P ≤ 0.005) and the facemask and compression only groups had a significantly lower PaO2 (P < 0.02) when compared to the orotracheal tube group. There was no difference between the PaO2 of the mouth-to-nose group compared to the orotracheal tube group at 3 or 6 min. Gastric distension, regurgitation, gas leakage around the mouth, and ineffective breaths were all noted in both the face mask and mouth-to-nose group. The results of this study supports that orotracheal intubation is the preferred technique for ventilation during CPR in dogs. When orotracheal intubation is not possible, face mask ventilation or mouth-to-nose ventilation would be reasonable alternatives. When oxygen supplementation is available, face mask ventilation is likely to be superior. Appropriate training for both face mask and mouth-to-nose ventilation techniques is recommended.

Utstein-style guidelines on uniform reporting of in-hospital cardiopulmonary resuscitation in dogs and cats. A RECOVER statement.

To provide recommendations for reviewing and reporting clinical in-hospital cardiopulmonary resuscitation (CPR) events in dogs and cats and to establish nonambiguous operational definitions for CPR terminology. Consensus guidelines. International, academia, referral practice, general practice, and human medicine. An international veterinary Utstein task force was convened in April 2013 in San Francisco to determine the scope of the project, the variables to be reported, their definitions, and a reporting template. Factors that were essential for meaningful data reporting and were amenable to accurate collection (ie, core variables) and additional variables useful for research projects and hypothesis generation (ie, supplemental variables) were defined. Consensus on each item was either achieved during that meeting or during the subsequent online modified Delphi process and dialogue between task force members. Variables were defined and categorized as hospital, animal, event (arrest), and outcome variables. This report recommends a template for standardized reporting of veterinary in-hospital CPR studies involving dogs or cats. Core elements include the suspected cause(s) and location of arrest, first rhythm identified, the occurrence of return of spontaneous circulation (ROSC) of more than 30 seconds (any ROSC) or more than 20 minutes (sustained ROSC), survival to discharge, and functional capacity at discharge. If CPR is discontinued or the patient is euthanized by owner request, a reason is reported. The task force suggests a case report form to be used for individual resuscitation events. The availability of these veterinary small animal CPR reporting guidelines will encourage and facilitate high-quality veterinary CPR research, improve data comparison between studies and across study sites, and serve as the foundation for veterinary CPR registries.

Acid base, electrolyte, glucose, and lactate values during cardiopulmonary resuscitation in dogs and cats.

To report acid base, electrolyte, glucose, and lactate values collected during or immediately after cardiopulmonary resuscitation (CPR) in dogs and cats. Retrospective study. University Teaching Hospital. Thirty-two dogs and 10 cats. None. Blood gas, electrolyte, glucose, and lactate values measured during CPR or within 5 minutes of return of spontaneous circulation (ROSC) were retrospectively evaluated. The time of blood collection with respect to the occurrence of cardiopulmonary arrest (CPA), the initiation of CPR or ROSC was noted. Forty-two venous blood samples were analyzed, 24 collected during CPR and 18 samples were collected within 5 minutes of ROSC. Metabolic acidosis and hyperlactatemia were evident in all samples in the study while an increased PvCO2 occurred in 88% of samples collected during CPR and in 61% of samples collected following ROSC. Hyperkalemia occurred in 65% of all cases, decreased ionized calcium was evident in 18%, hypoglycemia was evident in 21% while hyperglycemia was evident in 62%. There was no significant difference in any parameter evaluated between dogs and cats during CPR. There was no significant difference of any variable measured during the first 15 minutes of CPA versus those measured more than 15 minutes following CPA. When the values measured during the first 5 minutes of ROSC were compared to those measured during CPR, the pH and PvO2 were significantly lower in the CPR group. Biochemical abnormalities including metabolic acidosis, hyperkalemia, ionized hypocalcemia, hypoglycemia, and hyperglycemia can be identified during CPR and immediately following ROSC. The therapeutic and prognostic relevance of these changes are yet to be defined and may prove to be useful to guide patient management in the future.

Cardiopulmonary Resuscitation in Dogs and Cats

Cardiopulmonary Resuscitation in Dogs and Cats

The effect of using an impedance threshold device on hemodynamic parameters during cardiopulmonary resuscitation in dogs

To investigate the hemodynamic effects following the use of an impedance threshold device (ITD) in a canine model of cardiopulmonary arrest. Experimental, randomized crossover study. Cardiovascular research laboratory at a university veterinary center. Eight purpose bred beagle dogs. Dogs were anesthetized and instrumented for the measurement of right atrial pressure , systolic blood pressure, mean blood pressure, and diastolic arterial blood pressure, end-tidal CO(2) , and carotid blood flow (CBF). CBF was determined via ultrasonic flow probe placed around the carotid artery. Animals were taking part in an unassociated terminal study and following subsequent euthanasia with pentobarbital, standardized cardiopulmonary resuscitation (CPR) was performed with an impedance threshold device attached (ITD-CPR group) and without (S-CPR group). Order of treatment was randomized. ITD group had increased CBF, coronary perfusion pressure, and a decrease in right atrial diastolic pressure. No differences in end-tidal CO(2) , diastolic arterial blood pressure, mean blood pressure, or systolic blood pressure were seen. Return of spontaneous circulation was not observed in any of the animals Use of the ITD resulted in favorable changes in hemodynamic parameters in dogs undergoing CPR. The ITD may be a useful adjunct during CPR in dogs and warrants clinical evaluation.

Registries and Selection Bias

Outcomes researchers share a strong interest in determining what is being achieved in practice. In the quest to reveal what is actually being done in medicine, we are often in a position to use existing data about clinical practice and patient experience to answer relevant questions, rather than having to generate data de novo. Patient registries, with their size, scope, and focus on patients who represent those seen in clinical practice, have become an increasingly common source of data for outcomes researchers. There is much to like about patient registries. These organized collections of data about clinical practice are a vehicle by which we can assemble massive amounts of information about patients and use it to assess quality of care, identify patterns of care, facilitate real-world research, and improve performance. In cardiovascular medicine, registries capture information about patients with acute coronary syndromes and heart failure as well as those who undergo procedures related to cardiac catheterization, percutaneous coronary intervention, carotid stents, and internal cardioverter defibrillators. Federal agencies are turning to registries to provide information about quality and produce insights about how to best practice medicine through an emphasis on comparative effectiveness research. Outcomes research articles based on registry data are numerous, including those from NRMI, CRUSADE, GWTG-HF, …

Effects of dexmedetomidine on cerebral circulation and systemic hemodynamics after cardiopulmonary resuscitation in dogs

Our purpose was to examine the effect of dexmedetomidine, when used with phenylephrine during cardiopulmonary resuscitation (CPR), on the cerebral and systemic circulations. In pentobarbital-anesthetized, mechanically ventilated dogs, we evaluated pial vessel diameters, cerebral oxygen extraction, and systemic hemodynamics before and after cardiac arrest (5 min) and resuscitation, in the presence or absence of dexmedetomidine (n = 7 each; dexmedetomidine or control group). In both groups: (a) pial arterioles were dilated at 5 and 15 min after CPR, and had returned to baseline diameters at 30 min; (b) sagittal sinus pressure was significantly raised at 5 and 15 min after CPR; and (c) cerebral oxygen extraction was decreased at 5, 15, and 30 min after CPR, and had returned to baseline level at 60 min after CPR. We could find no differences between the two groups in the cerebral circulation after CPR. However, the number of defibrillation electric shocks required to restore spontaneous circulation (5.5 vs 3.6; P < 0.05), the dose of phenylephrine used for CPR (1193 microg vs 409 microg; P < 0.01), and the number of postresuscitation ventricular ectopic beats observed during the first 120 min after successful resuscitation (1606 vs 348; P < 0.05) were all significantly lower in the dexmedetomidine group. Although intravenous dexmedetomidine, as used for CPR, does not have a beneficial effect on either cerebral vessels or cerebral oxygen extraction, it may reduce the number of defibrillation shocks needed and the number of postresuscitation ventricular ectopic beats, and help to bring about stable systemic circulation after CPR.

Aspiration in transtracheal oxygen insufflation with different insufflation flow rates during cardiopulmonary resuscitation in dogs.

We investigated whether transtracheal insufflation of oxygen with different insufflation flow rates protects against aspiration of gastric contents during cardiopulmonary resuscitation (CPR). Its ventilation and oxygenation effects were also evaluated. Cardiac arrest was induced in anesthetized and paralyzed 18 mongrel dogs. Chest compression using an automatic thumper was performed while the dogs randomly received no mechanical ventilation (Group I, n = 6) or were transtracheally insufflated with 4 L/min oxygen (Group II, n = 6) or 10 L/min oxygen (Group III, n = 6). Blood samples were drawn every 5 min for 20 min for blood gas analysis. the mouths of the dogs were then filled with 70 mL mixed barium, and 10 min after chest compression, chest radiographs were taken to evaluate the incidence of pulmonary aspiration. Results showed that pulmonary aspiration occurred in all dogs of Group I and three of the six dogs in Group II, whereas dogs in Group III were free from pulmonary aspiration. Both transtracheal oxygen insufflation groups maintained oxygen saturation significantly better than Group I, but mild hypercapnia was observed in all groups after 20 min of CPR. We conclude that transtracheal oxygen insufflation, but not chest compression alone, was able to maintain oxygenation for 20 min during CPR in dogs with cardiac arrest. Mild hypercapnia was noted in all groups. Chest compression alone caused pulmonary aspiration, whereas insufflation of 10 L O(2)/min provided better protection against pulmonary aspiration than that of 4 L O(2)/min.

Non-invasive diagnosis of ischemic brain damage after cardiopulmonary resuscitation in dogs by using transcranial Doppler ultrasonography.

We have attempted to identify whether it is possible to utilize transcranial Doppler ultrasonography to evaluate the brain damage that occurs after resuscitation from 3 min (control group) and 12 min (damage group) of cardiac arrest in dogs. In this study we used transcranial Doppler ultrasonography to follow the basilar arterial flow and middle cerebral arterial flow for 180 min following the induction of cardiac arrests. Two abnormal waveform patterns (the "to-and-fro" and "diastolic no-flow" patterns) were found in all dogs in the damage group whereas abnormal waveforms were not detected in the control group. Pathological diagnosis revealed that, compared with the control group, the damage group recognized ischemic alteration at the level of the hippocampus and caudate nucleus. In conclusion, this study shows that the basilar arterial flow of observed with transcranial Doppler ultrasonography may be use for the prediction of outcome and the diagnosis of brain damage in the dog.

Response to repeated equal doses of epinephrine during cardiopulmonary resuscitation in dogs

Study Objective: Advanced cardiac life support (ACLS) guidelines recommend a 3- to 5-minute interval between repeated doses of epinephrine. This recommendation does not take into account the dose of epinephrine used, and only very limited data exist regarding the hemodynamic responses to repeated “high” doses of epinephrine. The objective of this study was to analyze the hemodynamic responses to repeated, equal, high doses of epinephrine administered during cardiopulmonary resuscitation (CPR) in a canine model of ventricular fibrillation (VF). Methods: This study used a secondary analysis of data collected in a prospective, randomized study, primarily designed to assess the effects of acid buffers in a canine model of cardiac arrest. VF was electrically induced. After 10 minutes, CPR was initiated, including ventilation with F IO 2=1.0, external chest compressions, administration of epinephrine (0.1 mg/kg repeated every 5 minutes) and defibrillation. Animals were randomized to receive either NaHCO 3, Carbicarb, tromethamine (THAM), or NaCl. The hemodynamic variables were sampled from each experiment’s paper chart at 1-minute intervals, and the responses to the first 4 doses of epinephrine were compared. Results: Thirty-six animals (9 in each buffer group) were included in this analysis. Systolic, diastolic, and coronary perfusion pressures increased steeply (by 100%, 130%, and 190%, respectively) only after the first epinephrine dose. These pressures peaked at 2 to 3 minutes and decreased only slightly and insignificantly during the rest of the 5-minute interval, until the next epinephrine dose. No further significant increases in arterial pressures were observed in response to the next 3 doses of epinephrine, administered 5 minutes apart. Conclusion: The hemodynamic effects of high-dose epinephrine (0.1 mg/kg) during CPR appear to last longer than 5 minutes. Therefore, longer intervals between doses may be justified with high doses of epinephrine. [Bar-Joseph G, Weinberger T, Ben-Haim S. Response to repeated equal doses of epinephrine during cardiopulmonary resuscitation in dogs. Ann Emerg Med. January 2000;35:3-10.]

Effect of the no-flow interval and hypothermia on cerebral blood flow and metabolism during cardiopulmonary resuscitation in dogs.

We sought (1) to determine the effect of brief periods of no flow on the subsequent forebrain blood flow during cardiopulmonary resuscitation (CPR) and (2) to test the hypothesis that hypothermia prevents the impact of the no-flow duration on cerebral blood flow (CBF) during CPR. No-flow intervals of 1.5, 3, and 6 minutes before CPR at brain temperatures of 28 degreesC and 38 degreesC were compared in 6 groups of anesthetized dogs. Microsphere-determined CBF and metabolism were measured before and during vest CPR adjusted to maintain cerebral perfusion pressure at 25 mm Hg. Increasing the no-flow interval from 1.5 to 6 minutes at 38 degreesC decreased the CBF (18. 6+/-3.6 to 6.1+/-1.7 mL/100 g per minute) and the cerebral metabolic rate (2.1+/-0.3 to 0.7+/-0.2 mL/100 g per minute) during CPR. Cooling to 28 degreesC before and during the arrest eliminated the detrimental effects of increasing the no-flow interval on CBF (16. 8+/-1.0 to 14.8+/-1.9 mL/100 g per minute) and cerebral metabolic rate (1.1+/-0.1 to 1.3+/-0.1 mL/100 g per minute). Unlike the forebrain, 6 minutes of preceding cardiac arrest did not affect brain stem blood flow during CPR. Increasing the no-flow interval to 6 minutes in normothermic animals decreases the supratentorial blood flow and cerebral metabolic rate during CPR at a cerebral perfusion pressure of 25 mm Hg. Cooling to 28 degreesC eliminates the detrimental impact of the 6-minute no-flow interval on the reflow produced during CPR. The brain-protective effects of hypothermia include improving reflow during CPR after cardiac arrest. The effect of hypothermia and the impact of short durations of no flow on reperfusion indicate that increasing viscosity and reflex vasoconstriction are unlikely causes of the "no-reflow" phenomenon.

Effects of intra-aortic balloon occlusion on hemodynamics during, and survival after cardiopulmonary resuscitation in dogs.

To evaluate the effect of balloon occlusion of the proximal descending aorta during cardiopulmonary resuscitation (CPR) on hemodynamics, restoration of spontaneous circulation, and 24-hr survival. Prospective, randomized, controlled trial. Experimental laboratory in a university hospital. Eighteen anesthetized dogs. INTERVENTIONS; Catheters were placed for hemodynamic and blood gas monitoring. An aortic balloon catheter was placed with its tip just distal to the left subclavian artery. After 10 mins of ventricular fibrillation without CPR, 3 mins of Basic Life Support (chest compressions and ventilation with 100% oxygen) was followed by up to 30 mins of Advanced Cardiac Life Support with canine drug dosages. In the treatment group (n = 8), the intra-aortic balloon was inflated when Advanced Cardiac Life Support started and not deflated until shortly after restoration of spontaneous circulation. The control animals (n = 10) were treated with an identical resuscitation but without intra-aortic balloon occlusion. In the treatment group, coronary perfusion pressure was greater during Advanced Cardiac Life Support (p = .026). Restoration of spontaneous circulation was more frequent (7/8 dogs) as compared with the control group (3/10 dogs) (p = .025). There was a trend toward greater 24-hr survival in the treatment group (5/8 dogs) than in the control group (3/10 dogs). Balloon occlusion of the proximal descending aorta during experimental CPR improves restoration of spontaneous circulation. Further laboratory and human studies are needed to determine the clinical efficacy of this technique.

Coronary Perfusion Pressure During Cardiopulmonary Resuscitation After Spinal Anesthesia in Dogs

Cardiac arrest during spinal anesthesia is a rare event, but when it does happen cardiopulmonary resuscitation (CPR) is often ineffectual. This study examines the effect of spinal anesthesia on coronary perfusion pressure (CPP) during CPR and the subsequent response of CPP to epinephrine administration. Twenty mongrel dogs were anesthetized, and randomly assigned to a spinal injection with either 0.5 mg/kg bupivacaine or with an equivalent volume of normal saline. Twenty minutes later, ventricular fibrillation was electrically induced and after 1 min CPR was started. CPP was measured every minute. After 4 min of CPR, epinephrine 0.01 mg/kg was given followed by 0.1, 0.2, and 0.4 mg/kg epinephrine intravenously (IV) at 6, 8, 10 min of CPR, respectively. The bupivacaine (n = 11) group had significantly less CPP than the sham spinal (n = 8) group, 12-13 mm Hg as compared to 27-34 mm Hg. Only 4/11 dogs (36%) in the bupivacaine group had CPP > or = 15 mm Hg during the first 4 min after arrest as compared to 8/8 (100%) in the sham spinal group. This increased to 7/11 dogs (64%) after 0.01 mg/kg epinephrine and to 9/11 after 0.1 mg/kg epinephrine. Total spinal anesthesia decreases CPP and thus the efficacy of CPR in dogs below the threshold previously established for predicting successful resuscitation. Epinephrine is effective in increasing CPP during CPR above the critical threshold. These data suggest that if cardiac arrest occurs during spinal anesthesia, epinephrine should be given in doses of 0.01-0.02 mg/kg IV initially and then increasing to 0.1 mg/kg IV. When this does not work, and ineffective CPR is suspected, alternative resuscitative measures should be considered.

Acidemia and brain pH during prolonged cardiopulmonary resuscitation in dogs: Stroke 1995; 26/6: 1028–1034

Acidemia and brain pH during prolonged cardiopulmonary resuscitation in dogs: Stroke 1995; 26/6: 1028–1034

Phenylephrine plus propranolol improves the balance between myocardial oxygen supply and demand during experimental cardiopulmonary resuscitation

Epinephrine increases coronary blood flow but may not improve the balance between myocardial oxygen supply and demand during cardiopulmonary resuscitation (CPR). The objective of this study was to determine whether this balance can be improved by administering a relatively pure alpha-adrenergic vasoconstrictor, alone or in combination with a beta-adrenergic blocker. We measured coronary perfusion pressures during CPR and myocardial adenosine 5'-triphosphate (ATP) and lactate concentrations in biopsies obtained immediately after 10 minutes of CPR in six control dogs and in three groups of six dogs each given large doses of epinephrine, phenylephrine, or phenylephrine plus propranolol during CPR. Coronary perfusion pressure during CPR was higher in the three treated groups than in the control group, although differences were limited to the early portion of CPR in dogs given epinephrine or phenylephrine alone. Postresuscitation myocardial ATP concentration was significantly higher (29.5 +/- 3.0 vs 22.6 +/- 1.8 nmol/mg of protein, p < 0.05) and myocardial lactate concentration tended to be lower (52.8 +/- 13.6 vs 78.5 +/- 15.2 nmol/mg of protein) than in the control group in dogs given both phenylephrine and propranolol. In contrast, myocardial ATP concentration tended to be lower than in the control group in epinephrine-treated dogs, and myocardial lactate concentrations were higher than in the control group in dogs treated with either epinephrine (p < 0.05) or phenylephrine alone (p = 0.052). We conclude that the balance between myocardial oxygen supply and demand during CPR can be improved by administering a combination of phenylephrine and propranolol, but not by administering large doses of epinephrine or phenylephrine alone.

Phenylephrine plus propranolol improves the balance between myocardial oxygen supply and demand during experimental cardiopulmonary resuscitation

Epinephrine increases coronary blood flow but may not improve the balance between myocardial oxygen supply and demand during cardiopulmonary resuscitation (CPR). The objective of this study was to determine whether this balance can be improved by administering a relatively pure α-adrenergic vasoconstrictor, alone or in combination with a β-adrenergic blocker. We measured coronary perfusion pressures during CPR and myocardial adenosine 5′-triphosphate (ATP) and lactate concentrations in biopsies obtained immediately after 10 minutes of CPR in six control dogs and in three groups of six dogs each given large doses of epinephrine, phenylephrine, or phenylephrine plus propranolol during CPR. Coronary perfusion pressure during CPR was higher in the three treated groups than in the control group, although differences were limited to the early portion of CPR in dogs given epinephrine or phenylephrine alone. Postresuscitation myocardial ATP concentration was significantly higher (29.5 ± 3.0 vs 22.6 ± 1.8 nmol/mg of protein, p < 0.05) and myocardial lactate concentration tended to be lower (52.8 ± 13.6 vs 78.5 ± 15.2 nmol/mg of protein) than in the control group in dogs given both phenylephrine and propranolol. In contrast, myocardial ATP concentration tended to be lower than in the control group in epinephrine-treated dogs, and myocardial lactate concentrations were higher than in the control group in dogs treated with either epinephrine (p < 0.05) or phenylephrine alone (p = 0.052). We conclude that the balance between myocardial oxygen supply and demand during CPR can be improved by administering a combination of phenylephrine and propranolol, but not by administering large doses of epinephrine or phenylephrine alone.