Dynamic Course of Clinical State Transitions in Patients Undergoing Advanced Life Support after Out-of-Hospital Cardiac Arrest.

OBJECTIVES: Studies of out-of-hospital cardiac arrest generally document the presenting (pulseless electrical activity [PEA], ventricular fibrillation/tachycardia (VF/VT), asystole), and the final states (resuming stable spontaneous circulation [s-ROSC], being declared dead). Only a few studies described the transitions between clinical states during advanced life support (ALS). The aim of this study was to describe and analyze the dynamics of state transitions during ALS. METHODS: A retrospective analysis of 464 OHCA events was conducted. Any observed state and its corresponding changing time were documented through continuous electrocardiographic and trans-thoracic impedance recording. RESULTS: When achieved, most s-ROSCs were obtained by 30 min, regardless of the presenting state. After this time point, the persistence of any transient state was associated with a great probability of being declared dead. The most probable change for VF/VT or PEA at any time was the transition to asystole (36.4% and 34.4%, respectively); patients in asystole at any time had a 70% probability of death. Patients achieving s-ROSC mostly came from a VF/VT state.In most cases, the presenting rhythm tended to persist over time during ALS. Asystole was the most stable state; a higher degree of instability was observed when the presenting rhythms were VF/VT or PEA. Transient ROSC episodes occurred mainly as the first transition after the presenting state, especially for initial PEA. CONCLUSIONS: An understanding of the dynamic course of clinical state transitions during ALS may allow treatment strategies to be tailored in patients affected by OHCA.

Impact of 'synchronous' and 'asynchronous' CPR modality on quality bundles and outcome in out-of-hospital cardiac arrest patients.

During cardiopulmonary resuscitation (CPR), the need to interrupt chest compressions to provide synchronous ventilations prevents blood flow continuity, reducing the possibility to ensure high-quality CPR bundles of care and, thus, having a potentially negative impact on perfusion and patient outcome. Contemporaneous asynchronous chest compressions and ventilations may avoid these potentially negative effects. Only a few studies measured the CPR quality metrics during synchronous and asynchronous CPR modality and its relation to patient outcome. A prospective observational study was conducted on 285 consecutive adult patients with out-of-hospital cardiac arrest treated by EMS teams over a 30-month period. Ventilation rate, chest compression fraction (i.e. cardiac arrest time spent delivering uninterrupted chest compressions compared to total cardiac arrest time) and chest compression rate per minute were collected in real time by defibrillators and analysed through a dedicated software (electrical cardiac activity through the ECG, chest compression and ventilations through the transthoracic impedance) during synchronous and asynchronous CPR modalities. During asynchronous CPR modality, higher ventilation rate and chest compression fraction (p < 0.001), and lower chest compression rate per minute (p < 0.001) were ensured, being all cited metrics more adherent to the high-quality CPR bundles. Ventilation rate provided during the whole CPR was an independent predictor for a good neurological outcome (OR 3.795, p = 0.005). Asynchronous chest compression and ventilation ensured the most adequate chest compression fraction, uninterrupted chest compression rate and ventilation rate.

Impact of Transitory ROSC Events on Neurological Outcome in Patients with Out-of-Hospital Cardiac Arrest.

In out-of-hospital cardiac arrest (OHCA), the occurrence of temporary periods of return to spontaneous circulation (t-ROSC) has been found to be predictive of survival to hospital discharge. The relationship between the duration of t-ROSCs and OHCA outcome has not been explored yet. The aim of this prospective observational study was to analyze the duration of t-ROSCs during OHCA and its impact on outcome. Defibrillator-recorded OHCA events were analyzed via dedicated software. The number of t-ROSC episodes and their overall durations were recorded. The study endpoint was the good neurologic outcome at hospital discharge. Among 285 patients included in the study, 45 (15.8%) had one or more t-ROSCs. The likelihood of t-ROSC occurrence was higher in patients with a shockable rhythm (p = 0.009). The cumulative length of t-ROSC episodes was significantly higher for patients who achieved sustained ROSC (p < 0.001). The adjusted cumulative t-ROSC length was an independent predictor for good neurological outcome at hospital discharge (OR 1.588, 95% CI 1.017 to 2.481; p = 0.042). According to our findings and data from previous studies, t-ROSC episodes during OHCA should be considered as a favorable prognostic factor, encouraging continuing resuscitative efforts.

Respiratory mechanics in COPD patients who failed non-invasive ventilation: role of intrinsic PEEP.

Non-invasive positive pressure ventilation (NPPV) is the first choice to treat exacerbations in COPD patients. NPPV can fail owing to different causes related to gas exchange impairment (RF group) or intolerance (INT group). To assess if the respiratory mechanical properties and the ratio between the dynamic and static intrinsic positive end-expiratory pressure (PEEP(i),dyn/PEEP(i),stat), reflecting lung mechanical inequalities, were different between groups, 29 COPD patients who failed NPPV (15 RF and 14 INT) were studied, early after the application of invasive ventilation. Blood gas analysis, clinical status, and mechanical properties were measured. pH was higher in INT patients before intubation (p<0.001). PEEP(i),dyn/PEEP(i),stat was found higher in INT group with (p=0.021) and without PEEP (ZEEP, p<0.01). PEEP(i),dyn/PEEP(i),stat was exponentially associated with the duration of NPPV in INT group (p=0.011). INT and RF patients had similar impairment of respiratory system resistance and elastance.