Wolfgang Dersch

Mechanical Ventilation During Cardiopulmonary Resuscitation With Intermittent Positive-pressure Ventilation, Bilevel Ventilation, or Chest Compression Synchronized Ventilation in a Pig Model*

Objective:Mechanical ventilation with an automated ventilator is recommended during cardiopulmonary resuscitation with a secured airway. We investigated the influence of intermittent positive-pressure ventilation, bilevel ventilation, and the novel ventilator mode chest compression synchronized ventilation, a pressure-controlled ventilation triggered by each chest compression, on gas exchange, hemodynamics, and return of spontaneous circulation in a pig model. Design:Animal study. Setting:University laboratory. Subjects:Twenty-four three-month-old female domestic pigs. Interventions:The study was performed on pigs under general anesthesia with endotracheal intubation. Arterial and central venous catheters were inserted and IV rocuronium (1 mg/kg) was injected. After 3 minutes of cardiac arrest (ventricular fibrillation at t = 0 min), animals were randomized into intermittent positive-pressure ventilation (control group), bilevel, or chest compression synchronized ventilation group. Following 10 minute uninterrupted chest compressions and mechanical ventilation, advanced life support was performed (100% O2, up to six defibrillations, vasopressors). Measurements and Main Results:Blood gas samples were drawn at 0, 4 and 13 minutes. At 13 minutes, hemodynamics was analyzed beat-to-beat in the end-inspiratory and end-expiratory cycle comparing the IPPV with the bilevel group and the CCSV group. Data were analyzed with the Mann-Whitney U test. Return of spontaneous circulation was achieved in five of eight (intermittent positive-pressure ventilation), six of eight (bilevel), and four of seven (chest compression synchronized ventilation) pigs. The results of arterial blood gas analyses at t = 4 minutes and t = 13 minutes (torr) were as follows: PaO2 intermittent positive-pressure ventilation, 143 (76/256) and 262 (81/340); bilevel, 261 (109/386) (p = 0.195 vs intermittent positive-pressure ventilation) and 236 (86/364) (p = 0.878 vs intermittent positive-pressure ventilation); and chest compression synchronized ventilation, 598 (471/650) (p < 0.001 vs intermittent positive-pressure ventilation) and 634 (115/693) (p = 0.054 vs intermittent positive-pressure ventilation); PaCO2 intermittent positive-pressure ventilation, 40 (38/43) and 45 (36/52); bilevel, 39 (35/41) (p = 0.574 vs intermittent positive-pressure ventilation) and 46 (42/49) (p = 0.798); and chest compression synchronized ventilation, 28 (27/32) (p = 0.001 vs intermittent positive-pressure ventilation) and 26 (18/29) (p = 0.004); mixed venous pH intermittent positive-pressure ventilation, 7.34 (7.31/7.35) and 7.26 (7.25/7.31); bilevel, 7.35 (7.29/7.37) (p = 0.645 vs intermittent positive-pressure ventilation) and 7.27 (7.17/7.31) (p = 0.645 vs intermittent positive-pressure ventilation); and chest compression synchronized ventilation, 7.34 (7.33/7.39) (p = 0.189 vs intermittent positive-pressure ventilation) and 7.35 (7.34/7.36) (p = 0.006 vs intermittent positive-pressure ventilation). Mean end-inspiratory and end-expiratory arterial pressures at t = 13 minutes (mm Hg) were as follows: intermittent positive-pressure ventilation, 28.0 (25.0/29.6) and 27.9 (24.4/30.0); bilevel, 29.1 (25.6/37.1) (p = 0.574 vs intermittent positive-pressure ventilation) and 28.7 (24.2/36.5) (p = 0.721 vs intermittent positive-pressure ventilation); and chest compression synchronized ventilation, 32.7 (30.4/33.4) (p = 0.021 vs intermittent positive-pressure ventilation) and 27.0 (24.5/27.7) (p = 0.779 vs intermittent positive-pressure ventilation). Conclusions:Both intermittent positive-pressure ventilation and bilevel provided similar oxygenation and ventilation during cardiopulmonary resuscitation. Chest compression synchronized ventilation elicited the highest mean arterial pressure, best oxygenation, and a normal mixed venous pH during cardiopulmonary resuscitation.

Chest Compression Synchronized Ventilation versus Intermitted Positive Pressure Ventilation during Cardiopulmonary Resuscitation in a Pig Model

Background Guidelines recommend mechanical ventilation with Intermitted Positive Pressure Ventilation (IPPV) during resuscitation. The influence of the novel ventilator mode Chest Compression Synchronized Ventilation (CCSV) on gas exchange and arterial blood pressure compared with IPPV was investigated in a pig model. Methods In 12 pigs (general anaesthesia/intubation) ventricular fibrillation was induced and continuous chest compressions were started after 3min. Pigs were mechanically ventilated in a cross-over setting with 5 ventilation periods of 4min each: Ventilation modes were during the first and last period IPPV (100% O2, tidalvolumes = 7ml/kgKG, respiratoryrate = 10/min), during the 2nd, 3rd and 4th period CCSV (100% O2), a pressure-controlled and with each chest compression synchronized breathing pattern with three different presets in randomized order. Presets: CCSVA: Pinsp = 60mbar, inspiratorytime = 205ms; CCSVB: Pinsp = 60mbar, inspiratorytime = 265ms; CCSVC: Pinsp = 45mbar, inspiratorytime = 265ms. Blood gas samples were drawn for each period, mean arterial (MAP) and centralvenous (CVP) blood pressures were continuously recorded. Results as median (25%/75%percentiles). Results Ventilation with each CCSV mode resulted in higher PaO2 than IPPV: PaO2: IPPVfirst: 19.6(13.9/36.2)kPa, IPPVlast: 22.7(5.4/36.9)kPa (p = 0.77 vs IPPVfirst), CCSVA: 48.9(29.0/58.2)kPa (p = 0.028 vs IPPVfirst, p = 0.0001 vs IPPVlast), CCSVB: 54.0 (43.8/64.1) (p = 0.001 vs IPPVfirst, p = 0.0001 vs IPPVlast), CCSVC: 46.0 (20.2/58.4) (p = 0.006 vs IPPVfirst, p = 0.0001 vs IPPVlast). Both the MAP and the difference MAP-CVP did not decrease during twelve minutes CPR with all three presets of CCSV and were higher than the pressures of the last IPPV period. Conclusions All patterns of CCSV lead to a higher PaO2 and avoid an arterial blood pressure drop during resuscitation compared to IPPV in this pig model of cardiac arrest.

Advanced life support and mechanical ventilation.

Purpose of reviewArtificial ventilation is one of the best known resuscitation procedures. It is generally accepted that there must be oxygen delivery to vital organs during cardiac arrest and resuscitation in order to prevent irreversible damage, but there is an increasing number of ventilation concepts for resuscitation. Traditional and alternative methods of ventilation are reviewed. Recent findingsThe need for positive-pressure ventilation during resuscitation as an essential gold standard might be overestimated at least in the first minutes of cardiopulmonary resuscitation (CPR). The co-founders of the concept of cardiocerebral resuscitation could show positive effects of a sole passive oxygenation at the beginning of advanced life support (ALS). Research was published on continuous positive airway pressure (CPAP) ventilation as well as on CPAP plus pressure support ventilation. In addition to positive-pressure ventilation, the use of an impedance threshold device, partly in addition with active compression–decompression CPR, was investigated in both experimental and clinical settings. None of these methods alone could be proven to improve the outcome of cardiac arrest. The role of high oxygen concentration during CPR also remains unclear. SummaryPositive-pressure ventilation with pure oxygen remains, in clinical practice, the gold standard in ALS. Further research should focus on the role of passive oxygenation during early ALS. The concentration of oxygen needed during resuscitation has to be defined and alternative ventilation patterns, regarding the impact of CPR, should be investigated.

AP015 Chest compression synchronized ventilation during CPR: Technical solution and flow-volume curves of a novel ventilator mode

Mechanical ventilation with an automated ventilator is recommended during CPR with secured airway 1 . We developed and investigated the novel ventilator mode Chest Compression Synchronized Ventilation (CCSV), a pressure controlled ventilation triggered by each chest compression. The new ventilator mode and trigger technology are described and the resulting flow-volume curves were investigated in a pig model.

Sauerstoff in der Notfallmedizin – Fluch oder Segen?

Oxygen is the best known and well accepted medication in emergency medicine. In most emergencies high doses of oxygen are an essential part of treatment and seemed to be nearly free of adverse effects. Studies of the last two decades show hints to possible adverse effects of hyperoxia during post-resuscitation-care and myocardial infarction. These results should be critically reviewed and may lead to a rational use of oxygen in emergency care.

Impella support compared to medical treatment for post-cardiac arrest shock after out of hospital cardiac arrest

AIMS To compare survival outcomes of Impella support and medical treatment in patients with post-cardiac arrest cardiogenic shock related to acute myocardial infarction (AMI). METHODS Retrospective single center study of patients resuscitated from out of hospital cardiac arrest (OHCA) due to AMI with post-cardiac arrest cardiogenic shock between September 2014 and September 2016. Patients were either assisted with Impella or received medical treatment only. Survival outcomes were compared using propensity score-matched analysis to account for differences in baseline characteristics between both groups. RESULTS A total of 90 consecutive patients with post-cardiac arrest shock due to AMI were included; 27 patients in the Impella group and 63 patients in the medical treatment group. Patients with Impella support had a longer duration of low-flow time (29.54 ± 10.21 versus 17.57 ± 8.3 min, p < 0.001), higher lactate levels on admission (4.75 [IQR 3.8-11] versus 3.6 [IQR 2.6-3.9] mmol/L, p = 0.03) and lower baseline systolic LVEF (25% [IQR 25-35] versus 45% [IQR 35-51.25], p < 0.001) as compared to patients without circulatory support. After propensity score matching, patients with Impella support had a significantly higher survival to hospital discharge (65% versus 20%, p = 0.01) and 6-months survival (60% versus 20%, p = 0.02). CONCLUSION The results from our study suggest that Impella support is associated with significantly better survival to hospital discharge and at 6 months compared to medical treatment in OHCA patients admitted with post-cardiac arrest cardiogenic shock and AMI.

Dantrolene versus amiodarone for cardiopulmonary resuscitation: a randomized, double-blinded experimental study

Dantrolene was introduced for treatment of malignant hyperthermia. It also has antiarrhythmic properties and may thus be an alternative to amiodarone for the treatment of ventricular fibrillation (VF). Aim of this study was to compare the return of spontaneous circulation (ROSC) with dantrolene and amiodarone in a pig model of cardiac arrest. VF was induced in anesthetized pigs. After 8 min of untreated VF, chest compressions and ventilation were started and one of the drugs (amiodarone 5 mg kg−1, dantrolene 2.5 mg kg−1 or saline) was applied. After 4 min of initial CPR, defibrillation was attempted. ROSC rates, hemodynamics and cerebral perfusion measurements were measured. Initial ROSC rates were 7 of 14 animals in the dantrolene group vs. 5 of 14 for amiodarone, and 3 of 10 for saline). ROSC persisted for the 120 min follow-up in 6 animals in the dantrolene group, 4 after amiodarone and 2 in the saline group (n.s.). Hemodynamics were comparable in both dantrolene group amiodarone group after obtaining ROSC. Dantrolene and amiodarone had similar outcomes in our model of prolonged cardiac arrest, However, hemodynamic stability was not significantly improved using dantrolene. Dantrolene might be an alternative drug for resuscitation and should be further investigated.

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