Impacts of chest compression cycle length and real-time feedback with a CPRmeter® on chest compression quality in out-of-hospital cardiac arrest: study protocol for a multicenter randomized controlled factorial plan trial.

BACKGROUND: With a survival rate of 6 to 11%, out-of-hospital cardiac arrest (OHCA) remains a healthcare challenge with room for improvement in morbidity and mortality. The guidelines emphasize the highest possible quality of cardiopulmonary resuscitation (CPR) and chest compressions (CC). It is essential to minimize CC interruptions, and therefore increase the chest compression fraction (CCF), as this is an independent factor for survival. Survival is significantly and positively correlated with the suitability of CCF targets, CC frequency, CC depth, and brief predefibrillation pause. CC guidance improves adherence to recommendations and allows closer alignment with the CC objectives. The possibility of improving CCF by lengthening the time between two CC relays and the effect of real-time feedback on the quality of the CC must be investigated. METHODS: Using a 2 × 2 factorial design in a multicenter randomized trial, two hypotheses will be tested simultaneously: (i) a 4-min relay rhythm improves the CCF (reducing the no-flow time) compared to the currently recommended 2-min relay rate, and (ii) a guiding tool improves the quality of CC. Primary outcomes (i) CCF and (ii) correct compression score will be recorded by a real-time feedback device. Five hundred adult nontraumatic OHCAs will be included over 2 years. Patients will be randomized in a 1:1:1:1 distribution receiving advanced CPR as follows: 2-min blind, 2 min with guidance, 4-min blind, or 4 min with guidance. Secondary outcomes are the depth, frequency, and release of CC; length (care, no-flow, and low-flow); rate of return of spontaneous circulation; characteristics of advanced CPR; survival at hospital admission; survival and neurological state on days 1 and 30 (or intensive care discharge); and dosage of neuron-specific enolase on days 1 and 3. DISCUSSION: This study will contribute to assessing the impact of real-time feedback on CC quality in practical conditions of OHCA resuscitation. It will also provide insight into the feasibility of extending the relay rhythm between two rescuers from the currently recommended 2 to 4 min. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03817892 . Registered on 28 January 2019.

Distribution of neurokinin A-like and serotonin immunoreactivities within the vertical lobe complex in Sepia officinalis.

Immunohistochemistry, using antibodies raised against mammalian neurokinin A (NKA) and serotonin (5-HT), was applied in double-staining experiments to map these molecules within the vertical lobe complex (inferior frontal, superior frontal, post-frontal, vertical, subvertical and precommissural lobes). NKA-like and 5-HT immunoreactivities were detected in all the lobes of the vertical lobe complex but were never colocalized in cell bodies or fibres. Except for the cell layers of the superior frontal lobe, both types of labelled cell bodies were observed in all the lobes. Both types of immunoreactive fibres were detected in all the neuropils and interestingly revealed clear subdivisions within some lobes, e.g., 5-HT-IR fibres were more abundant in the peripheral part of the vertical lobe whereas NKA-IR ones were widely observed in both the peripheral and central parts. In cephalopods, the vertical lobe complex is involved in learning and memory; thus, our results strongly suggest that one or more NKA-like and 5-HT molecules may function as neurochemical messengers in these cognitive processes.