The comparative pathology of open chest vs. mechanical closed chest cardiopulmonary resuscitation in dogs

2024 RECOVER Guidelines: Advanced Life Support. Evidence and knowledge gap analysis with treatment recommendations for small animal CPR

OBJECTIVE

To systematically review the evidence and devise clinical recommendations on advanced life support (ALS) in dogs and cats and to identify critical knowledge gaps.

DESIGN

Standardized, systematic evaluation of literature pertinent to ALS following Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Prioritized questions were each reviewed by Evidence Evaluators, and findings were reconciled by ALS Domain Chairs and Reassessment Campaign on Veterinary Resuscitation (RECOVER) Co-Chairs to arrive at treatment recommendations commensurate to quality of evidence, risk:benefit relationship, and clinical feasibility. This process was implemented using an Evidence Profile Worksheet for each question that included an introduction, consensus on science, treatment recommendations, justification for these recommendations, and important knowledge gaps. A draft of these worksheets was distributed to veterinary professionals for comment for 4 weeks prior to finalization.

SETTING

Transdisciplinary, international collaboration in university, specialty, and emergency practice.

RESULTS

Seventeen questions pertaining to vascular access, vasopressors in shockable and nonshockable rhythms, anticholinergics, defibrillation, antiarrhythmics, and adjunct drug therapy as well as open-chest CPR were reviewed. Of the 33 treatment recommendations formulated, 6 recommendations addressed the management of patients with nonshockable arrest rhythms, 10 addressed shockable rhythms, and 6 provided guidance on open-chest CPR. We recommend against high-dose epinephrine even after prolonged CPR and suggest that atropine, when indicated, is used only once. In animals with a shockable rhythm in which initial defibrillation was unsuccessful, we recommend doubling the defibrillator dose once and suggest vasopressin (or epinephrine if vasopressin is not available), esmolol, lidocaine in dogs, and/or amiodarone in cats.

CONCLUSIONS

These updated RECOVER ALS guidelines clarify the approach to refractory shockable rhythms and prolonged CPR. Very low quality of evidence due to absence of clinical data in dogs and cats continues to compromise the certainty with which recommendations can be made.

Cardiac arrest in the perioperative period: a consensus guideline for identification, treatment, and prevention from the European Society of Anaesthesiology and Intensive Care and the European Society for Trauma and Emergency Surgery

INTRODUCTION

Cardiac arrest in the operating room is a rare but potentially life-threatening event with mortality rates of more than 50%. Contributing factors are often known, and the event is recognised rapidly as patients are usually under full monitoring. This guideline covers the perioperative period and is complementary to the European Resuscitation Council guidelines.

MATERIAL AND METHODS

The European Society of Anaesthesiology and Intensive Care and the European Society for Trauma and Emergency Surgery jointly nominated a panel of experts to develop guidelines for the recognition, treatment, and prevention of cardiac arrest in the perioperative period. A literature search was conducted in MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials. All searches were restricted to publications from 1980 to 2019 inclusive and to the English, French, Italian and Spanish languages. The authors also contributed individual, independent literature searches.

RESULTS

This guideline contains background information and recommendation for the treatment of cardiac arrest in the operating room environment, and addresses controversial topics such as open chest cardiac massage, resuscitative endovascular balloon occlusion and resuscitative thoracotomy, pericardiocentesis, needle decompression, and thoracostomy.

CONCLUSIONS

Successful prevention and management of cardiac arrest during anaesthesia and surgery requires anticipation, early recognition, and a clear treatment plan. The ready availability of expert staff and equipment must also be taken into consideration. Success not only depends on medical knowledge, technical skills and a well-organised team using crew resource management, but also on an institutional safety culture embedded in everyday practice through continuous education, training, and multidisciplinary co-operation.

Cardiac arrest in the perioperative period: a consensus guideline for identification, treatment, and prevention from the European Society of Anaesthesiology and Intensive Care and the European Society for Trauma and Emergency Surgery

INTRODUCTION

Cardiac arrest in the operating room is a rare but potentially life-threatening event with mortality rates of more than 50%. Contributing factors are often known, and the event is recognised rapidly as patients are usually under full monitoring. This guideline covers the perioperative period and is complementary to the European Resuscitation Council (ERC) guidelines.

MATERIAL AND METHODS

The European Society of Anaesthesiology and Intensive Care and the European Society for Trauma and Emergency Surgery jointly nominated a panel of experts to develop guidelines for the recognition, treatment and prevention of cardiac arrest in the perioperative period. A literature search was conducted in MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials. All searches were restricted to publications from 1980 to 2019 inclusive and to the English, French, Italian and Spanish languages. The authors also contributed individual, independent literature searches.

RESULTS

This guideline contains background information and recommendation for the treatment of cardiac arrest in the operating room environment, and addresses controversial topics such as open chest cardiac massage (OCCM), resuscitative endovascular balloon occlusion (REBOA) and resuscitative thoracotomy, pericardiocentesis, needle decompression and thoracostomy.

CONCLUSION

Successful prevention and management of cardiac arrest during anaesthesia and surgery requires anticipation, early recognition and a clear treatment plan. The ready availability of expert staff and equipment must also be taken into consideration. Success not only depends on medical knowledge, technical skills and a well organised team using crew resource management but also on an institutional safety culture embedded in everyday practice through continuous education, training and multidisciplinary co-operation.

Feasibility of open-chest cardiopulmonary resuscitation through a transdiaphragmatic approach in dogs

OBJECTIVE

To describe and evaluate the feasibility of a transdiaphragmatic (TD) approach for open-chest cardiopulmonary resuscitation (OCCPR) as an alternative to a traditional lateral thoracotomy (LT) in a canine cadaver model.

STUDY DESIGN

Randomized noninferiority ex vivo study.

ANIMALS

Fourteen canine cadavers weighing 17.4-30.2 kg.

METHODS

An LT and a TD approach to the heart were performed in each cadaver. The order of procedures as well as an assignment to specific operators were randomized before starting the study. Data recorded included the time between incision and initiation of cardiac compressions; time between initiation of the first suture placement and closure of the intrapleural space; time between initiation of the first suture placement and final skin suture; trauma to pulmonary, cardiac, hepatic and neurovascular structures; distance between the caval foramen and diaphragmatic incision; the intercostal space entered during LT; and appropriate closure.

RESULTS

The mean time between incision and initiation of cardiac compressions for the TD approach (85 ± 35 seconds) was noninferior to the LT (84 ± 28 seconds). The pleural space was closed faster after the TD approach (531 ± 276 seconds) than after the lateral approach (817 ± 294 seconds, P = .03). Total duration of closure did not differ between techniques (P = .11). There was no difference between the complication rates of each approach.

CONCLUSION

The TD approach did not prolong the procedure or increase the complication rate compared with an LT.

CLINICAL SIGNIFICANCE

This study provides evidence to support additional investigation of the TD approach for OCCPR to determine its efficacy and safety in live animals.

Protective effect of vascular endothelial growth factor against cardiopulmonary bypass-associated acute kidney injury in beagles

The present study aimed to examine the hypothesis that vascular endothelial growth factor (VEGF) has a protective effect against cardiopulmonary bypass (CPB)-associated acute kidney injury (AKI). Eighteen male beagles were randomly allocated to three groups (n=6 per group): Sham group, animals received sternotomy without going through CPB; CPB group, animals received CPB only; VEGF group, animals received CPB and VEGF. VEGF infusion was completed 1 h prior to the initiation of CPB. Renal microcirculation perfusion, serum creatinine (SCr) and blood urea nitrogen (BUN), histopathological injury score and apoptotic index were determined. Hypoxia inducible factor-1α, VEGF, phosphorylated (p)-Akt serine/threonine kinase (Akt), p-endothelial nitric oxide synthase (eNOS), cleaved caspase-3, B-cell lymphoma 2 (Bcl-2) and cluster of differentiation (CD)95 expression levels were assessed by western blot analysis, Enzyme-linked immunosorbent assay quantitative assays were used to evaluate tumor necrosis factor (TNF)-α, interleukin (IL)-6, superoxide dismutase and malondialdehyde levels. Renal microcirculation perfusion of the VEGF group was higher than that of the CPB group (P<0.05) and lower than that of the sham surgery group (P<0.05). SCr and BUN were significantly elevated after CPB in the CPB and VEGF groups, with significantly lower levels in group VEGF than group CPB. Renal pathology scores and apoptotic indices were significantly lower in the VEGF group than the CPB group. Levels of TNF-α, IL-6 in the VEGF group were significantly lower than in the CPB group. Levels of VEGF, p-Akt, p-eNOS and Bcl-2 expression in the VEGF group increased significantly in comparison with group CPB. Cleaved caspase-3 in the VEGF group was significantly lower than in the group CPB. CPB-associated reduction of renal microcirculation perfusion may predispose to AKI. VEGF appears to provide a protective effect on the kidneys through improvement in renal microperfusion.

Open-Chest Cardiopulmonary Resuscitation after Cardiac Arrest in Cases of Blunt Chest or Abdominal Trauma: A Consecutive Series of 38 Cases

BACKGROUND

According to the literature, the overall outcome in a patient population with chest or abdominal injury with initial cardiac arrest has to be rated as poor. In cases of penetrating injuries, open-chest cardiopulmonary resuscitation (CPR) has been recommended as a treatment option to improve the survival rate. The aim of this study was to prove equal outcome for patients with blunt chest or abdominal trauma.

METHODS

During a 5-year period, a consecutive patient series admitted to an urban Level I trauma center was examined. Only patients with blunt trauma and witnessed cardiac arrest, who had a documented, uninterrupted closed-chest CPR (CCCPR) of less than 20 minutes were included in this study (n=38). Exclusion criteria were age over 70 years, penetrating injuries, CCCPR of more than 20 minutes, as well as nonprofessional bystander resuscitation.

RESULTS

Four of 38 patients survived. In comparison with the group of nonsurvivors, both groups showed a similar age and gender ratio (mean age, 28, 32, respectively). The mean Injury Severity Scale was 54 (range, 42-66) in the survivor group and 66 (range, 29-75) in the nonsurvivor group, respectively. The time of CCCPR was on average 13 minutes (range, 11-15 minutes) for the survivors and 16 minutes (range, 1-20 minutes) for the nonsurvivors.

CONCLUSION

Patients with blunt trunk trauma and cardiac arrest after hemorrhagic shock may benefit from open-chest CPR with the same probability as shown for patients with penetrating injuries. This is especially true if the procedure is started as soon as possible, but at the latest within 20 minutes after initial CCCPR.

Minimally invasive direct cardiac massage versus closed-chest cardiopulmonary resuscitation in a porcine model of prolonged ventricular fibrillation cardiac arrest

Open chest cardiac massage has been shown to be superior to closed-chest cardiopulmonary resuscitation for both hemodynamics produced during resuscitation and ultimate resuscitation success. The inexperience of many rescuers with emergency thoracotomy, along with the associated morbidity contributes to the continued reluctance in the use of invasive cardiopulmonary resuscitation techniques. A device has been developed for performing 'minimally invasive' direct cardiac massage. This technique was compared to standard closed-chest CPR for resuscitation results in 20 swine during prolonged ventricular fibrillation cardiac arrest. Minimally invasive direct cardiac massage was superior to closed-chest CPR for return of spontaneous circulation (7/10 vs. 2/10; P<0.02) and coronary perfusion pressure at 30 min of CPR (17+/-9 vs. 6+/-6 mmHg; P<0.05). No significant injuries altering outcome were found with the invasive device. Throughout most of the time course of the study no significant differences in end-tidal expired carbon dioxide levels were noted. Nor were there any differences in 24-h survival. Improvements in assuring proper placement of the device on the epicardium should make this technique a potent advanced cardiac life support adjunct.

New thoughts on cardiopulmonary resuscitation

The results of cardiopulmonary resuscitation (CPR) have been distressingly poor when one considers the amount of research in this field since 1960. Accordingly, some improvements to present protocols have been suggested. Some of the suggestions can be applied by practicing veterinarians to increase the success rate for external chest massage. In addition, veterinarians are encouraged to switch to internal cardiac massage early in the resuscitation period.

The biphasic mechanism of blood flow during cardiopulmonary resuscitation: a physiologic comparison of active compression-decompression and high-impulse manual external cardiac massage

STUDY OBJECTIVE

Dismal survival in patients receiving standard manual CPR provided the rationale for the investigation of alternate methods of closed-chest circulatory support. Active compression-decompression (ACD) and high-impulse CPR are alternatives to standard manual CPR. This study was designed to test the hypothesis that ACD CPR provides superior cardiopulmonary hemodynamics due to an active decompression phase when compared with high-impulse manual CPR.

PARTICIPANTS

Hemodynamics were studied during ACD and high-impulse CPR in eight adult beagles.

DESIGN

Four animals were chronically instrumented and four were studied acutely. In an additional four animals, ACD was compared with sham ACD CPR. Each CPR technique was performed sequentially for 2 minutes, in random order, at a rate of 120, 50% duty cycle, and 1.5 to 2.0 in of compression depth. Measurements obtained included aortic, right atrial, left ventricular, and coronary perfusion pressures (in mm Hg); pulmonary artery flow, and left ventricular dimension.

RESULTS

ACD maximized cardiopulmonary hemodynamics, including coronary perfusion pressure and stroke volume, compared with both high-impulse manual and sham ACD CPR. ACD CPR also increased left ventricular pressure change per unit time during decompression, and these changes correlated well with left ventricular volume changes.

CONCLUSION

In the intact dog, ACD CPR generates physiologically and statistically superior hemodynamics when compared with high-impulse manual CPR. Improved blood flow seems to be related to more efficient ventricular filling and emptying. These findings emphasize the biphasic nature of CPR and the importance of active decompression.