Clinical pilot study of different hand positions during manual chest compressions monitored with capnography.

PURPOSE OF THE STUDY: Optimal hand position for chest compressions during cardiopulmonary resuscitation is unknown. Recent imaging studies indicate significant inter-individual anatomical variations, which might cause varying haemodynamic responses with standard chest compressions. This prospective clinical pilot study intended to assess the feasibility of utilizing capnography to optimize chest compressions and identify the optimal hand position. MATERIALS AND METHODS: Intubated cardiac arrest patients treated by the physician manned ambulance between February and December 2011 monitored with continuous end-tidal CO2 (EtCO2) measurements were included. One minute of chest compressions at the inter-nipple line (INL) optimized using EtCO2 feedback, was followed by four 30-s intervals with compressions at four different sites; INL, 2 cm below the INL, 2 cm below and to the left of INL and 2 cm below and to the right of INL. RESULTS: Thirty patients were included. At the end of each 30-s interval median (range) EtCO2 was 3.1 kPa (0.7-8.7 kPa) at INL, 3.5 kPa (0.5-10.7) 2 cm below INL, 3.5 kPa (0.5-10.3 kPa) 2 cm below and to the left of INL, and 3.8 kPa (0.4-8.8 kPa) 2 cm below and to the right of INL (p=0.4). The EtCO2 difference within each subject between hand positions with maximum and minimum values varied between individuals from 0.2 to 3.4 kPa (median 0.9 kPa). CONCLUSION: Monitoring and optimizing chest compressions using capnography was feasible. We could not demonstrate one superior hand position, but inter-individual differences suggest optimal hand position might vary significantly among patients.

Strong and weak aspects of an established post-resuscitation treatment protocol-A five-year observational study.

AIM OF STUDY: Favourable hospital survival increased from 26% to 56% in the implementation phase of a new standard operating procedure (SOP) for treatment after out-of hospital cardiac arrest (OHCA) in 2003. We now evaluate protocol adherence and survival rates after five years with this established SOP. METHODS: This observational study is based on prospectively collected registry data from all OHCA patients with cardiac aetiology admitted with spontaneous circulation to Ulleval Hospital between September 2003 and January 2009. Three patient categories are described based on early assessment in the emergency department: conscious, comatose, and comatose patients receiving only palliative care, with main focus on comatose patients receiving active treatment. RESULTS: Of 248 patients, 22% were consciousness on admission, 70% were comatose and received active treatment, while 8% received only palliative care. Favourable survival from admittance to discharge remained at 56% throughout the study period. Among actively treated patients 83% received emergency coronary angiography and 48% underwent subsequent percutaneous coronary intervention. In this cohort 63% had an acute myocardial infarction, ten of whom did not receive emergency coronary angiography. Among actively treated comatose patients, 6% survived with unfavourable neurology, while 51% of the deaths followed treatment withdrawal after prognostication of severe brain injury. CONCLUSION: The previously reported doubling in survival rate remained throughout a five-year study period. Establishing reliable indication for emergency coronary angiography and interventions and validating prognostication rules in the hypothermia era are important challenges for future studies.

A comparison of intravascular and surface cooling techniques in comatose cardiac arrest survivors.

OBJECTIVES: Mild therapeutic hypothermia after out-of-hospital cardiac arrest is usually achieved either by surface cooling or by core cooling via the patient's bloodstream. We compared modern core (Coolgard) and surface (Arctic Sun) cooling devices with a zero hypothesis of equal cooling, complications, and neurologic outcomes. DESIGN: Single-center observational study. SETTING: University hospital medical and cardiac intensive care units. PATIENTS: One hundred sixty-seven consecutive patients comatose after out-of-hospital cardiac arrest of all causes treated with mild therapeutic hypothermia in a 5-yr period. INTERVENTIONS: Nonrandomized allocation to core or surface cooling depending on availability and physician preference. MEASUREMENTS AND MAIN RESULTS: All out-of-hospital cardiac arrest patients' records were reviewed for relevant data regarding medical history, cardiac arrest event, prehospital care, in-hospital treatment, and complications. Survivor neurologic function was reassessed at follow-up after 6 to 12 months. Baseline patient and arrest episode characteristics were similar in the treatment groups. There was no significant difference in survival with good neurologic function, either to hospital discharge (surface, 34/90, 38%; core, 34/75, 45%; p=.345) or at follow-up (surface, 34/88, 39%; core, 34/75, 45%; p=.387). Time from cardiac arrest to achieving mild therapeutic hypothermia was equal with both devices (surface, 273 min, interquartile range 158-330; core, 270 min, interquartile range 190-360; p=.479). There were significantly more episodes of sustained hyperglycemia among the surface-cooled patients (surface, 64/92, 70%; core, 36/75, 48%; p=.005) and significantly more hypomagnesaemia among core-cooled patients (surface, 16/87, 18%; core, 27/74, 37%; p=.01). CONCLUSIONS: In this study, surface and core cooling of out-of-hospital cardiac arrest patients following the same established postresuscitation treatment protocol resulted in similar survival to hospital discharge and comparable neurologic function at follow-up.

Discriminating the effect of accelerated compression from accelerated decompression during high-impulse CPR in a porcine model of cardiac arrest.

AIM OF THE STUDY: Piston based mechanical chest compression devices deliver compressions and decompressions in an accelerated pattern, resulting in superior haemodynamics compared to manual compression in animal studies. The present animal study compares haemodynamics during two different hybrid compression patterns to a standard compression pattern resembling that of modern mechanical chest compression devices. METHOD: In 12 anaesthetized domestic pigs in ventricular fibrillation, coronary perfusion pressures (CPP) and cerebral cortical blood flow (CCBF) was measured, and transesophageal echocardiography (TEE) was performed. Two hybrid compression patterns, one with accelerated trapezoid compression and slower sinusoid decompression (TrS), and one with slower sinusoid compression and accelerated trapezoid decompression (STr), were tested against a standard accelerated trapezoid compression-decompression pattern (TrTr) in a cross-over randomised setup. RESULTS: There were 7% (1, 14, p=0.046) lower CCBF and 3 mmHg (1, 5, p=0.017) lower CPP with the TrS compared to TrTr pattern. No significant difference between STr and TrTr pattern in either CCBF, 6% (-3, 15, p=0.176) or CPP, 0 mmHg (-2, 3, p=0.703) was present. Our TEE recordings were insufficient for haemodynamic comparison between the different compression-decompression patterns. Despite standardized sternal piston position and placement of the pigs, TEE revealed varying degree of asymmetrical heart chamber compression in the animals. CONCLUSION: Both cardiac and cerebral perfusion benefited from accelerated decompression, while accelerated compression did not improve haemodynamics. The evolution of mechanical CPR is dependent on further research on mechanisms generating forward blood flow during external chest compressions.

Advanced life support performance with manual and mechanical chest compressions in a randomized, multicentre manikin study.

AIM OF THE STUDY: Clinical mechanical chest compression studies report diverging outcomes. Confounding effects of variability in hands-off fraction (HOF) and timing of necessary tasks during advanced life support (ALS) may contribute to this divergence. Study site variability in these factors coupled to randomization of cardiopulmonary resuscitation (CPR) method was studied during simulated cardiac arrest prior to a multicentre clinical trial. METHOD: Ambulance personnel from four sites were tested in randomized, simulated cardiac arrest scenarios with manual CPR or load-distributing band CPR (LDB-CPR) on manikins. Primary emphasis was on HOF and time spent before necessary predefined ALS task (ALS milestones). Results are presented as mean differences (confidence interval). RESULTS: At the site with lowest HOF during manual CPR, HOF deteriorated with LDB-CPR by 0.06 (0.005, 0.118, p=0.04), while it improved at the two sites with highest HOF during manual CPR by 0.07 (0.019, 0.112, p=0.007) and 0.08 (0.004, 0.165, p=0.042). Initial defibrillation was 29 (3, 55, p=0.032)s delayed for LDB-CPR vs. manual CPR. Other ALS milestones trended toward earlier completion with LDB-CPR; only significant for intravenous access, mean difference 70 (24, 115, p=0.003)s. CONCLUSION: In this manikin study, HOF for manual vs. mechanical chest compressions varied between sites. Study protocol implementation should be simulation tested before launching multicentre trials, to optimize performance and improve reliability and scientific interpretation.