Reversal of inadequate cardiac output and perfusion during cardiopulmonary resuscitation by open-chest cardiac massage

Prevalence of mutations in BRCA and homologous recombination repair genes and real-world standard of care of Asian patients with HER2-negative metastatic breast cancer starting first-line systemic cytotoxic chemotherapy: subgroup analysis of the global BREAKOUT study

Background

The multinational BREAKOUT study (NCT03078036) sought to determine the prevalence of germline BRCA1/2 (gBRCA1/2) and somatic BRCA1/2 (sBRCA1/2) mutations and mutations in other homologous recombination repair (HRR) genes in women with HER2-negative metastatic breast cancer (MBC) starting first-line chemotherapy.

Methods

Genetic testing for gBRCA, sBRCA, and HRR gene mutations was performed in patients who started first-line chemotherapy for MBC in the last 90 days (341 patients across 14 countries) who were not selected based on risk factors for gBRCA mutations. We report data from the Asian cohort, which included patients in Japan (7 sites), South Korea (10 sites), and Taiwan (8 sites).

Results

Of 116 patients screened, 104 patients were enrolled in the Asian cohort. The median age was 53.0 (range 25–87) years. gBRCA1/2, gBRCA1, and gBRCA2 mutations were detected in 10.6% (11/104), 5.8% (6/104), and 4.8% (5/104) of patients, respectively; none had mutations in both gBRCA1 and gBRCA2. gBRCA1/2 mutations were detected in 10.0% (6/60) and 11.6% (5/43) of patients with hormone receptor-positive and triple-negative MBC, respectively. HRR gene mutations were tested in 48 patients without gBRCA mutations, and 5 (10.4%) had at least one HRR mutation in sBRCA, ATM, PALB2, and CHEK2.

Conclusion

We report for the first time the prevalence of gBRCA and HRR mutations in an Asian cohort of patients with HER2-negative MBC. Our results suggest that BRCA mutation testing is valuable to determine appropriate treatment options for patients with hormone receptor-positive or triple-negative MBC.

Study registration

NCT03078036.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-021-01283-4.

Are US informed consent requirements driving resuscitation research overseas?

Following a 2-year federally imposed moratorium on acute resuscitation research due to concern regarding the inability of patients in cardiac arrest to provide prospective, informed consent to participate in such research, the United States federal government in 1996 released regulations with provisions for exemption of prospective informed consent in certain types of emergency research. While very few acute resuscitation research studies have been attempted in the United States since that time, such research has continued overseas. We discuss one large multi-center, out-of-hospital trial of a device intended to improve the hemodynamics of cardiopulmonary resuscitation. After pilot implementation overseas, this trial could not be conducted in the United States, largely due to the difficulties and costs involved in implementing the requirements of the 1996 regulations. A recent European Union directive on the conduct of clinical trials may halt European research on patients who are unable to provide prospective, informed consent. The directive contains no provisions for exceptions or waiver of informed consent, and may hinder acute resuscitation research in Europe to an even greater degree than the 1996 regulations have in the United States.

Direct cardiac massage without major thoracotomy: feasibility and systemic blood flow

BACKGROUND

Open-chest cardiac massage (OC-CM) provides higher blood pressure and flow than closed-chest compression and may improve the probability of successful resuscitation from cardiac arrest. Its clinical use has been limited by its requirement for a major thoracotomy. The present pilot study tested the technical feasibility of performing effective direct cardiac massage without a major thoracic incision, by using a simple, manually-powered plunger-like device, inserted through a small thoracic incision, to cyclically compress the cardiac ventricles. The method was termed minimally-invasive direct cardiac massage (MID-CM). Systemic blood flow using MID-CM was compared to that with OC-CM, by both direct systemic hemodynamic measurements, cumulative metabolic indicators of the ratio of whole body oxygen delivery and oxygen consumption, and a metabolic index of pulmonary blood flow.

METHODS

In 12 large swine, baseline systemic and pulmonary hemodynamic measurements were performed. Arterial and mixed venous blood gases and metabolic indicators of systemic blood flow were measured. Ventricular fibrillation was induced and after 4 min, animals underwent either bimanual OC-CM (N = 6) or MID-CM (N = 6). At 10, 20 and 30 min, hemodynamic and metabolic measurements were repeated.

RESULTS

Systemic Blood Pressure: Aortic systolic and diastolic blood pressures were reduced from baseline levels with both OC-CM and MID-CM. No difference in pressure was noted between OC-CM and MID-CM groups. Pulmonary Artery Pressure: Pulmonary artery systolic pressure was elevated from baseline during OC-CM and MID-CM. Pulmonary artery diastolic pressures remained constant throughout the resuscitation period in both groups. No differences in pulmonary systolic or diastolic pressure were noted between OC-CM and MID-CM groups. A trend towards higher pulmonary systolic pressures appeared with MID-CM. Thermodilution Blood Flow: Cardiac index fell from baseline levels with OC-CM and MID-CM. No difference in cardiac index was noted between OC-CM and MID-CM groups. Metabolic Indices: Mixed venous O2 saturation decreased from baseline levels during resuscitation in both experimental groups, with a further decrease at 30 min compared to 10- and 20-min levels. No difference was noted between OC-CM and MID-CM groups at any point. Arterial pH was reduced from baseline levels at 30 min in both groups compared to baseline but no difference was noted between groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Mastering pediatric cardiopulmonary resuscitation

Premature and unexpected death, especially in children, is tragic and very unacceptable. Effective treatments for sudden death of pediatric patients continue to emerge. Modern cardiopulmonary resuscitation function began with the widespread introduction of closed-chest cardiac massage in 1960; however, despite 35 years of research and refinement, more than 90% of children who receive cardiopulmonary resuscitation do not survive. This article summarizes and expands on current treatment concepts for pediatric sudden death. Emphasis is placed on procedures and techniques that likely are accessible in most medical centers caring for critically ill and injured children.

The optimum timing of resuscitative thoracotomy for non-traumatic out-of-hospital cardiac arrest

Open-chest cardiopulmonary resuscitation (CPR) is a promising method for non-traumatic cardiac arrest. In this preliminary study, we investigated the optimum timing of thoracotomy which brings high rate of return of spontaneous circulation (ROSC) and keeps the incidence of unnecessary thoracotomy minimal. Ninety-five adult patients with non-traumatic out-of-hospital cardiac arrest were analyzed. Of those, 26 patients were treated by the open-chest CPR in a prospective consecutive fashion. In this group, the ROSC rate was investigated in connection with the interval from hospital arrival, or ambulance call, to thoracotomy. Another 69 patients were treated by standard CPR. In this uncontrolled group, the interval from arrival at hospital to ROSC was investigated to define the 'natural hospital course' by the conventional treatment. Patient characteristics in the open-chest CPR group and the standard CPR group were similar. In the open-chest CPR group, 15 patients obtained ROSC. There was a tendency that the ROSC rate was highest in the patients with thoracotomy within 5 min of hospital arrival and declined as the timing of thoracotomy was delayed. Similar tendency was noted when the timing of thoracotomy was counted from the ambulance call. In the standard CPR group, only two patients obtained ROSC during the initial 5 min of hospital course. These results suggest that thoracotomy within 5 min of hospital arrival brings the highest ROSC rate while keeps the incidence of unnecessary thoracotomy acceptable.

Internal cardiac massage and mediastinal irrigation in hypothermic cardiac arrest

Two unconscious patients with unknown past medical histories were found to be severely hypothermic, with core temperatures of 80.2 degrees F and 86.7 degrees F, respectively. During the course of active internal rewarming, both patients sustained a cardiac arrest. Emergency thoracotomies were immediately done, and internal cardiac massage with warmed mediastinal irrigation was performed. Spontaneous cardiac activity developed in both patients. Within 24 hours after resuscitation, both patients were responsive and following commands.

Open-chest cardiac massage. The possible rebirth of an old procedure

Open-chest cardiac massage was widely and successfully used for many decades before its virtual abandonment 25 years ago. Both experimental evidence and basic physiologic evidence indicate that it has many advantages over closed-chest massage (especially increased cardiac output). Both resuscitation techniques have specific and unique advantages and disadvantages: They are not mutually exclusive. However, significant increases in rates of survival after cardiac arrest cannot be expected with variations of closed-chest cardiac massage and standard advanced life support services. Therefore, physicians must be willing to support controlled human studies that can definitively determine the proper role of each in resuscitation after cardiac arrest.

Open chest cardiac massage: a review

Open-chest cardiopulmonary resuscitation (CPR) is physiologically superior to all external CPR methods studied thus far (P. Safer, Ann. Emerg. Med., 13 (1984) 856). Open-chest CPR should again be taught to physicians, and used more often after prolonged cardiac arrest. An extensive review on open cardiac massage is presented herein.

Lactic acidosis during closed-chest CPR in dogs

Survival after out-of-hospital cardiac arrest is intimately related to the time from cardiovascular collapse to the initiation of CPR, or downtime. Furthermore, the reperfusion technique that optimizes coronary and cerebral blood flow after cardiac arrest may also be dependent on downtime. Peak blood lactate levels have been shown to be unchanged throughout resuscitation and predictive of downtime in dogs subjected to cardiopulmonary arrest and open cardiac massage. The purpose of this study was to determine the course of arterial lactate levels in dogs subjected to a fibrillatory cardiopulmonary arrest and conventional closed-chest CPR (CCPR). Fourteen dogs were subjected to five minutes of cardiopulmonary arrest and 30 minutes of CCPR. Resuscitation was performed according to a standardized protocol. Arterial lactic acid samples were collected at timed intervals throughout the experiment. Mean arterial lactic acid levels increased significantly with each sampling interval during 30 minutes of CCPR (overall P less than .05). In nine dogs successfully resuscitated, there were no significant differences in mean arterial lactic acid levels after the return of spontaneous circulation (ROSC). Open-chest resuscitation after five minutes of ventricular fibrillation in dogs results in peak lactic acid levels that do not change significantly once internal cardiac massage is initiated. In contrast, CCPR in similarly arrested dogs does not appear to provide adequate tissue oxygenation and/or perfusion to prevent continuous lactic acid accumulation.

Open-chest cardiac massage after closed-chest compression in a canine model: when to intervene

Open-chest cardiac massage appears beneficial in improving hemodynamics during resuscitation efforts and in improving resuscitation success. The time between cardiac arrest and the initiation of open-chest cardiac massage is crucial. It would appear that if initiation of open chest cardiac massage is delayed for more than 20 min from the onset of cardiac arrest, little or no successful outcome can be expected. Further techniques for assessing the adequacy of closed-chest compression CPR are needed. Such techniques would allow early identification of ineffective resuscitation efforts and provide the opportunity for early change to other, presumably more effective, techniques.

Importance of the duration of inadequate coronary perfusion pressure on resuscitation from cardiac arrest

The effect of the duration of inadequate coronary perfusion pressure on resuscitation from cardiac arrest was examined in 32 mongrel dogs with a mean weight of 22 +/- 5 kg. In all dogs, the heart was electrically fibrillated and closed chest compression with assisted ventilation was performed for 15 minutes. At this time, all dogs had an inadequate coronary perfusion pressure (mean 7 +/- 9 mm Hg) and were randomized to a control group (group 1) with continued closed chest compression or to one of the three groups with open chest cardiac massage. These three groups differed only in the duration of continued closed chest compression before initiation of open chest massage (15, 20 and 25 minutes, respectively, in groups 2, 3 and 4). The control group (group 1) had no significant increase in coronary perfusion pressure, and only one of the eight dogs could be resuscitated. The three groups with open chest cardiac massage had a significant increase in coronary perfusion pressure (from 5 +/- 9 to 51 +/- 26 mm Hg, p less than 0.05), but the rate of successful resuscitation depended on the duration of inadequate coronary perfusion pressure before cardiac open chest massage. In group 2, six of eight dogs were resuscitated (p less than 0.05 compared with the control group); in group 3, three of eight dogs were resuscitated and in group 4 none of the eight dogs was resuscitated. The resuscitation rate was significantly (p less than 0.05) greater in group 2 than in group 4. These findings indicate that techniques that improve coronary perfusion pressure during cardiopulmonary resuscitation must be applied before extensive myocardial cellular dysfunction occurs if the probability of successful resuscitation is to be improved.

Rapid change in pulmonary vascular hemodynamics with pulmonary edema during cardiopulmonary resuscitation

Previous studies have shown that pulmonary edema occurs in half of all pre-hospital cardiac arrest victims who cannot be successfully resuscitated and is a major cause of hypoxemia and poor lung compliance during resuscitation. Pulmonary vascular hypertension and elevation of pulmonary capillary wedge pressure have been observed during cardiac resuscitation in humans. To further define the time course of the pulmonary hemodynamic changes, pulmonary artery diastolic pressure (PAd) was measured on a computerized trend recorder prior to, during, and immediately after arrest in three adult patients. Prior to arrest, PADP was 20.9 +/- 3.1 mm Hg. The PADP rose in all three patients by an average of 30.6% after 5-10 minutes and 71.3% after 10-15 minutes of CPR. Peak PADP reached 35.8 +/- 5.1 mm Hg (difference from pre-arrest level significant, P less than 0.001). In both patients who were resuscitated successfully, the PADP returned to baseline within 5 minutes of effective spontaneous circulation. The finding that such hemodynamic changes occur rapidly during resuscitation and can reverse quickly with resumption of effective spontaneous circulation is consistent with the time course for the early development of pulmonary edema. Development of pulmonary edema many hours following successful resuscitation likely involves other mechanisms.