Why chest compressions should start when systolic arterial blood pressure is below 50 mm Hg in the anaesthetised patient

Advanced life support interventions during intra-operative cardiac arrest among adults as reported to the 7th National Audit Project of the Royal College of Anaesthetists

BACKGROUND

Few existing resuscitation guidelines include specific reference to intra-operative cardiac arrest, but its optimal treatment is likely to require some adaptation of standard protocols.

METHODS

We analysed data from the 7th National Audit Project of the Royal College of Anaesthetists to determine the incidence and outcome from intra-operative cardiac arrest and to summarise the advanced life support interventions reported as being used by anaesthetists.

RESULTS

In the baseline survey, > 50% of anaesthetists responded that they would start chest compressions when the non-invasive systolic pressure was < 40-50 mmHg. Of the 881 registry patients, 548 were adult patients (aged > 18 years) having non-obstetric procedures under the care of an anaesthetist, and who had arrested during anaesthesia (from induction to emergence). Sustained return of spontaneous circulation was achieved in 425 (78%) patients and 338 (62%) were alive at the time of reporting. In the 365 patients with pulseless electrical activity or bradycardia, adrenaline was given as a 1 mg bolus in 237 (65%). A precordial thump was used in 14 (3%) patients, and although this was associated with return of spontaneous circulation at the next rhythm check in almost three-quarters of patients, in only one of these was the initial rhythm shockable. Calcium (gluconate or chloride) and 8.4% sodium bicarbonate were given to 51 (9%) and 25 (5%) patients, but there were specific indications for these treatments in less than half of the patients. A thrombolytic drug was given to 5 (1%) patients, and extracorporeal cardiopulmonary resuscitation was used in 9 (2%) of which eight occurred during cardiac procedures.

CONCLUSIONS

The specific characteristics of intra-operative cardiac arrest imply that its optimal treatment requires modifications to standard advanced life support guidelines.

Peri-operative cardiac arrest due to suspected anaphylaxis as reported to the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project (NAP7) of the Royal College of Anaesthetists studied peri-operative cardiac arrest. Among 59 cases reported as possible anaphylaxis, 33 (56%) were judged to be so by the review panel with high or moderate confidence. Causes in excluded cases included: isolated severe hypotension; bronchospasm; and oesophageal intubation. Severe bronchospasm leading to cardiac arrest was uncommon, but notably in one case led to a reported flat capnograph. In the baseline survey, anaesthetists estimated anaphylaxis as the cause of 10% of cases of peri-operative cardiac arrests and to be among the four most common causes. In a year-long registry of peri-operative cardiac arrest, suspected anaphylaxis was the seventh most common cause accounting for 4% of reports. Initial management was most often with low-dose intravenous adrenaline, and this was without complications. Both the NAP7 baseline survey and case registry provided evidence of reluctance to starting chest compressions when systolic blood pressure had fallen to below 50 mmHg and occasionally even when it was unrecordable. All 33 patients were resuscitated successfully but one patient later died. The one death occurred in a relatively young patient in whom chest compressions were delayed. Overall, peri-operative anaphylaxis leading to cardiac arrest occurred with a similar frequency and patterns of presentation, location, initial rhythm and suspected triggers in NAP7 as in the 6th National Audit Project (NAP6). Outcomes in NAP7 were generally better than for equivalent cases in NAP6.

Emergency treatment of peri-operative anaphylaxis: Resuscitation Council UK algorithm for anaesthetists

Peri-operative anaphylaxis is a rare but potentially catastrophic event which must be considered whenever unexpected and significant cardiovascular or respiratory compromise occurs during anaesthesia. The Resuscitation Council UK algorithm for peri-operative anaphylaxis highlights the importance of early intravenous adrenaline and fluid resuscitation and provides guidance on the treatment of refractory anaphylaxis and immediate follow-up. This algorithm is endorsed by the Royal College of Anaesthetists, Association of Anaesthetists, British Society of Allergy and Clinical Immunology and Clinical Immunology Professional Network of the British Society for Immunology. This document was produced by the Perioperative Allergy Network steering committee in collaboration with the Resuscitation Council UK.

Ventricular Assist Device Training and Emergency Management Among Pediatric Cardiac Intensive Care Physicians - Multicenter Cross-Sectional Survey

Background/Aim: Pediatric cardiac intensive care physicians practicing at centers that implant ventricular assist devices (VAD's) are exposed to increasing numbers of VAD patients, with a significant number of VAD-days. We aimed to delineate pediatric cardiac critical care practices surrounding routine and emergency management of VADs. Methodology: We administered a multicenter cross-sectional survey of pediatric cardiac intensive care unit (CICU) physicians in the United States and Canada. Survey distribution occurred between August 31st and October 26th 2021. Results: A total of 254 CICU physicians received a formal invitation to participate, with 108 returning completed surveys (42.5% response rate). Responses came from CICU attending physicians at 26 separate institutions. Respondents' level of experience was well distributed across junior, mid-level, and senior staff: less than 5 years (38%), 5-9 years (25%), and >/= 10 years (37%). Most respondents had received formal training in the management of VAD patients (n = 93, 86.1%), with training format including fellowship (61%), simulation (36%), and national/international conferences (26.5%). Dedicated advanced cardiac therapies teams were available at the institutions of 97.2% of respondents. A total of 78/108 (72.2%) described themselves as "comfortable" or "very comfortable" in pediatric VAD management. While 63% (68/108) of respondents reported that they had never performed (or overseen the performance of) chest compressions in a pediatric patient with a VAD, 37% (40/108) reported performing CPR at least once in a VAD patient. Conclusion: With no existing international guidelines for emergency cardiovascular care in the pediatric VAD population, our survey identifies an important gap in resuscitation recommendations.

Extremity tourniquets raise blood pressure and maintain heart rate

BACKGROUND

Tourniquets have been modified and used for centuries to occlude blood flow to control hemorrhage. More recently, the occlusion of peripheral vessels has been linked to resultant increases in blood pressure, which may provide additional therapeutic potential, particularly during states of low cardiac output.

OBJECTIVE

The objective of this study was to investigate a causal relationship between tourniquet application and blood pressure in healthy adults.

METHODS

Healthy adult volunteers were recruited to participate in this IRB-approved study. Each participant met inclusion criteria and demonstrated baseline normotension. Brachial cuff blood pressure and heart rate were recorded pre- and post-tourniquet application to the bilateral legs.

RESULTS

Twenty-seven adults aged 22 to 35 years participated and were included in analysis. The average systolic blood pressure was 122 ± 7 mmHg, diastolic blood pressure was 72 ± 9 mmHg, and heart rate was 70 ± 13 bpm. Following bilateral tourniquet application over the femoral vasculature, we observed a statistically significant increase in systolic (7 mmHg, p < 0.001) and diastolic (4 mmHg, p = 0.05) blood pressures with no significant change in heart rate (2 bpm, p > 0.05).

CONCLUSIONS

The elevations in systolic and diastolic blood pressures establish a dependent relationship between tourniquet application to the lower extremities and blood pressure elevation. These results may support new indications for tourniquet-use or extremity vessel occlusion in settings of hemodynamic instability.

A single-center, nonblinded, clinical trial comparing blood pressures before and after tourniquet application in healthy humans: A study protocol

INTRODUCTION

Cardiac arrest is the leading cause of natural death in the United States, and most surviving patients suffer from neurological dysfunction. Although this is recognized as a problem, there have been very few changes to the cardiopulmonary resuscitation (CPR) procedure. Tourniquets have been recognized for their ability to increase truncal blood pressure and have been shown to improve CPR outcomes in animal models. However, the relationship between tourniquet application and blood pressure elevation has not been adequately explored in healthy human adults.

OBJECTIVES

The objective of this study is to demonstrate that bilateral, non-invasive, peripheral vascular occlusion in the thighs results in an increased proximal systolic blood pressure ≥ 10 mmHg.

METHODS

This is a single-center, non-blinded clinical trial. Volunteers will be screened for eligibility at least 24 hours before the day of the trial. On the day of the trial, volunteers will undergo an informed consent process. If they choose to participate in the trial after informed consent, their baseline blood pressure will be measured. Volunteers will then have a Combat Application Tourniquet (CAT) applied to each thigh, and the windlasses will be tightened by IRB-approved personnel. Once no pulse can be felt in the lower extremity, blood pressure will be measured in the arm. This will be replicated three times, and the tourniquets will be loosened between trials to allow the volunteers to rest. Any complications that arise during the trial will be handled by the physician that is present.

ANALYSIS

Changes in systolic blood pressure and diastolic blood pressure will be analyzed using a Shapiro-Wilk test. Then, a one-way repeated measures analysis of variance (ANOVA) will be performed with a Holm-Sidak post-hoc test to determine the mean differences. The significance level will be set to 5% for statistical significance.

REGISTRY AND REGISTRATION NUMBER

Clinicaltrials.gov, NCT05324306.

Cardiac arrest caused by anaphylaxis refractory to prompt management: A case series and review of the literature

BACKGROUND

Anaphylaxis is a potentially life-threatening condition that occurs in the emergency department (ED). Although anaphylaxis is rapidly recognized and treated in the hospital compared with that in the community, in some cases, it does not respond to proper management.

OBJECTIVE

The aim of this study is to describe our experience of cases of refractory anaphylaxis leading to cardiac arrest in hospital, to review their characteristics compared with those seen in the community, and to discuss the best management practices for anaphylaxis-induced cardiac arrest with a literature review.

METHODS

We reviewed the medical records of patients referred to the ED with possible in-hospital anaphylaxis between January 2017 and May 2021. According to the anaphylaxis protocol, epinephrine, corticosteroid, and antihistamine were administered immediately on-site at our institution before the study period. Refractory anaphylaxis was defined as the development of anaphylaxis-induced cardiac arrest even after following the anaphylaxis protocol.

RESULTS

A total of 246 cases were evaluated for possible anaphylaxis, with 236 cases meeting the criteria for a diagnosis of anaphylaxis. Among them, 178 patients showed the signs and symptoms of shock, and cardiac arrest occurred in 6 patients (2.5%). Of the six patients, three had a return of spontaneous circulation before admission to the ED, while two died due to refractory cardiac arrest despite resuscitation in the ED. Following post-cardiac arrest care, including temperature management, one patient who received extracorporeal cardiopulmonary resuscitation survived neurologically intact.

CONCLUSION

We present our case series to highlight the risk of developing refractory anaphylaxis with subsequent in-hospital cardiac arrest. Patients may progress to cardiac arrest within minutes despite prompt recognition and management. If patients present with potentially fatal symptoms, a more aggressive approach, including intravenous adrenaline infusion, should be taken.

Chest Compressions in Pediatric Patients With Continuous-Flow Ventricular Assist Devices: Case Series and Proposed Algorithm

Patients with continuous flow ventricular assist devices (CF-VAD's) in the systemic ventricle (left ventricle or single ventricle) often have no palpable pulses, unreliable pulse oximetry waveforms and non-pulsatile arterial waveforms despite hemodynamic stability. When circulatory decompensation occurs, standard indicators to begin cardiopulmonary resuscitation (CPR) which are used in other pediatric patients (i.e., significant bradycardia or loss of pulse) cannot be applied in the same fashion. In this population, there may already be pulselessness and development of bradycardia in and of itself would not trigger chest compressions. There are no universal guidelines to dictate when to consider chest compressions in this population. As such, there may be a delay in decision-making or in recognizing the need for chest compressions, even in patients hospitalized in intensive care units (ICU) and cared for by experienced staff who perform CPR regularly. We present four examples of pediatric cardiac ICU patients from a single center who underwent CPR between 2018 and 2019. Based on this case series, we propose a decision-making algorithm for chest compressions in pediatric patients with CF-VADs in the systemic ventricle.

Cardiopulmonary resuscitation in special circumstances

Cardiopulmonary resuscitation prioritises treatment for cardiac arrests from a primary cardiac cause, which make up the majority of treated cardiac arrests. Early chest compressions and, when indicated, a defibrillation shock from a bystander give the best chance of survival with a good neurological status. Cardiac arrest can also be caused by special circumstances, such as asphyxia, trauma, pulmonary embolism, accidental hypothermia, anaphylaxis, or COVID-19, and during pregnancy or perioperatively. Cardiac arrests in these circumstances represent an increasing proportion of all treated cardiac arrests, often have a preventable cause, and require additional interventions to correct a reversible cause during resuscitation. The evidence for treating these conditions is mostly of low or very low certainty and further studies are needed. Irrespective of the cause, treatments for cardiac arrest are time sensitive and most effective when given early-every minute counts.

[Cardiac arrest under special circumstances]

These guidelines of the European Resuscitation Council (ERC) Cardiac Arrest under Special Circumstances are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required for basic and advanced life support for the prevention and treatment of cardiac arrest under special circumstances; in particular, specific causes (hypoxia, trauma, anaphylaxis, sepsis, hypo-/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), specific settings (operating room, cardiac surgery, cardiac catheterization laboratory, dialysis unit, dental clinics, transportation [in-flight, cruise ships], sport, drowning, mass casualty incidents), and specific patient groups (asthma and chronic obstructive pulmonary disease, neurological disease, morbid obesity, pregnancy).

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).