Comparison of relative and actual chest compression depths during cardiac arrest in children, adolescents, and young adults

Aim

Cardiopulmonary resuscitation (CPR) guidelines recommend specific chest compression (CC) target depths for children. We quantitatively describe relative anterior–posterior diameter (APD) depth, actual depth, and force of CCs during real CPR events in children.

Methods

CC depth and force were recorded during real CPR events in children ≥8 years using FDA-approved CC sensor. Patient chest APD was measured at conclusion of each CPR event. CC data was stratified and analyzed according to age (pre-puberty, 8–14 years; post-puberty, 15+ years). Relative (% APD) and actual CC depth, corrected for mattress deflection, were assessed and compared with American Heart Association (AHA) 2005 and 2010 pediatric CPR guidelines.

Results

35 events in 32 subjects included 16,158 CCs for data analysis: 16 pre-puberty (CCs = 7484, age 11.9 ± 2 years, APD 164.6 ± 25.1 mm); 19 post-puberty (CCs = 8674, age 18.0 ± 2.7 years, APD 196.5 ± 30.4 mm). After correction for mattress deflection, 92% of CC delivered to pre-puberty were <1/3 relative APD and 60% of CC were <38 mm actual depth. Mean actual CC depth (36.2 ± 9.6 mm vs. 36.8 ± 9.9 mm, p = 0.64), mean relative APD (22.5% ± 7.0% vs. 19.5 ± 6.7%, p = 0.13), and mean CC force (30.7 ± 7.6 kg vs. 33.6 ± 9.4 kg, p = 0.07) were not significantly less in pre-puberty vs. post-puberty.

Conclusions

During in-hospital cardiac arrest of children ≥8 years, CCs delivered by resuscitation teams were frequently <1/3 relative APD and <38 mm actual depth after mattress deflection correction, below pediatric and adult target guidelines. Mean CC actual depth and force were not significantly different in pre-puberty and post-puberty. Additional investigation to determine depth of CCs to optimize hemodynamics and outcomes is needed to inform future CPR guidelines.     

Eleven years of experience with extracorporeal cardiopulmonary resuscitation for paediatric patients with in-hospital cardiac arrest

Purpose

The study aims to describe 11 years of experience with extracorporeal cardiopulmonary resuscitation (ECPR) for in-hospital paediatric cardiac arrest in a university affiliated tertiary care hospital.

Methods

Paediatric patients who received extracorporeal membrane oxygenation (ECMO) during active extracorporeal cardiopulmonary resuscitation (ECPR) at our centre from 1999 to 2009 were included in this retrospective study. The results from three different cohorts (1999–2001, 2002–2005 and 2006–2009) were compared. Survival rates and neurological outcomes were analysed. Favourable neurological outcome was defined as paediatric cerebral performance categories (PCPC) 1, 2 and 3.

Results

We identified 54 ECPR events. The survival rate to hospital discharge was 46% (25/54), and 21 (84%) of the survivors had favourable neurological outcomes.The duration of CPR was 39 ± 17 min in the survivors and 52 ± 45 min in the non-survivors (p = NS). The patients with pure cardiac causes of cardiac arrest had a survival rate similar to patients with non-cardiac causes (47% (18/38) vs. 44% (7/16), p = NS).The non-survivors had higher serum lactate levels prior to ECPR (13.4 ± 6.4 vs. 8.8 ± 5.1 mmol/L, p < 0.01) and more renal failure after ECPR (66% (19/29) vs. 20% (5/25), p < 0.01).The patients resuscitated between 2006 and 2009 had shorter durations of CPR (34 ± 13 vs. 78 ± 76 min, p = 0.032) and higher rates of survival (55% (16/29) vs. 0% (0/8), p = 0.017) than those resuscitated between 1999 and 2002.

Conclusions

In our single-centre experience with ECPR for paediatric in-hospital cardiac arrest, the duration of CPR has become shorter and outcomes have improved in recent years. Higher pre-ECPR lactate levels and the presence of post-ECPR renal failure were associated with increased mortality. The presence of non-cardiac causes of cardiac arrest did not preclude successful ECPR outcomes. The duration of CPR was not significantly associated with poor outcomes in this study.     

Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: A prospective multicenter study

Background

Rescuer fatigue during cardiopulmonary resuscitation (CPR) is a likely contributor to variable CPR quality during clinical resuscitation efforts, yet investigations into fatigue and CPR quality degradation have only been performed in simulated environments, with widely conflicting results.

Objective

We sought to characterize CPR quality decay during actual in-hospital cardiac arrest, with regard to both chest compression (CC) rate and depth during the delivery of CCs by individual rescuers over time.

Methods

Using CPR recording technology to objectively quantify CCs and provide audiovisual feedback, we prospectively collected CPR performance data from arrest events in two hospitals. We identified continuous CPR “blocks” from individual rescuers, assessing CC rate and depth over time.

Results

135 blocks of continuous CPR were identified from 42 cardiac arrests at the two institutions. Median duration of continuous CPR blocks was 112 s (IQR 101–122). CC rate did not change significantly over single rescuer performance, with an initial mean rate of 105 ± 11/min, and a mean rate after 3 min of 106 ± 9/min (p = NS). However, CC depth decayed significantly between 90 s and 2 min, falling from a mean of 48.3 ± 9.6 mm to 46.0 ± 9.0 mm (p = 0.0006) and to 43.7 ± 7.4 mm by 3 min (p = 0.002).

Conclusions

During actual in-hospital CPR with audiovisual feedback, CC depth decay became evident after 90 s of CPR, but CC rate did not change. These data provide clinical evidence for rescuer fatigue during actual resuscitations and support current guideline recommendations to rotate rescuers during CC delivery.     

Novel adhesive glove device (AGD) for active compression-decompression (ACD) CPR results in improved carotid blood flow and coronary perfusion pressure in piglet model of cardiac arrest

Objective

ACD-CPR improves coronary and cerebral perfusion. We developed an adhesive glove device (AGD) and hypothesized that ACD-CPR using an AGD provides better chest decompression resulting in improved carotid blood flow as compared to standard (S)-CPR.

Design

Prospective, randomized and controlled animal study.

Methods

Sixteen anesthetized and ventilated piglets were randomized after 3 min of untreated VF to receive either S-CPR or AGD-ACD-CPR by a PALS certified single rescuer with compressions of 100 min⁻¹ and C:V ratio of 30:2. AGD consisted of a modified leather glove exposing the fingers and thumb. A wide Velcro patch was sewn to the palmer aspect of the glove and the counter Velcro patch was adhered to the pig's chest wall. Carotid blood flow was measured using ultrasound. Data (mean ± SD) was analyzed using one way ANOVA and unpaired t-test; p-value ≤ 0.05 was considered statistically significant.

Results

Right atrial pressure (mm Hg) during the decompression phase was lower during AGD-ACD-CPR (−3.32 ± 2.0) when compared to S-CPR (0.86 ± 1.8, p = 0.0007). Mean carotid blood flow was 53.2 ± 27.1 (% of baseline blood flow in ml/min) in AGD vs. 19.1 ± 12.5% in S-CPR, p = 0.006. Coronary perfusion pressure (CPP, mm Hg) was 29.9 ± 5.8 in AGD vs. 22.7 ± 6.9 in S-CPR, p = 0.04. There was no significant difference in time to ROSC and number of epinephrine doses.

Conclusion

Active chest decompression during CPR using this simple and inexpensive adhesive glove device resulted in significantly better carotid blood flow during the first 2 min of CPR.     

The impact of a step stool on cardiopulmonary resuscitation: a cross-over mannequin study

Objective

Shallow chest compressions and incomplete recoil are common during cardiopulmonary resuscitation (CPR) and negatively affect outcomes. A step stool has the potential to alter these parameters when performing CPR in a bed but the impact has not been quantified.

Methods

We conducted a cross-over design, simulated study of in-hospital cardiac arrest. Rescuers performed a total of four 2-min segments of uninterrupted chest compressions, half of which were on a step stool. Compression characteristics were measured using a CPR-sensing defibrillator and subjective impressions were obtained from rescuer surveys. Paired analyses were performed to measure the impact of the step stool, taking into account rescuer characteristics, including height.

Results

Fifty subjects, of whom 36% were men, with a median height of 169.8 cm (range 148.6–190.5) volunteered to participate. Use of a step stool resulted in an average increase in compression depth of 4 mm (p < 0.001) and 18% increase in incomplete recoil (p < 0.001). However, unlike with incomplete recoil, the effect was more pronounced in rescuers in the lowest height tertile (9 ± 9 mm vs 2 ± 6 mm for those rescuers taller than 167 cm, p = 0.006).

Conclusions

Using a step stool when performing CPR in a bed results in a trade-off between increased compression depth and increased incomplete recoil. Given the nonlinear relationship between the increase in compression depth and rescuer height, the benefit of a step stool may outweigh the risks of incomplete release for rescuers ≤167 cm in height. The benefit is less clear in taller rescuers.     

Investigation of the possibility of using ischemia-modified albumin as a novel and early prognostic marker in cardiac arrest patients after cardiopulmonary resuscitation

Background

Early and accurate prediction of survival to hospital discharge following resuscitation after cardiac arrest (CA) is a major challenge. Our aim was to investigate the levels of ischemia-modified albumin (IMA) and malondialdehyde (MDA) in CA patients and whether IMA levels are valuable early marker of post-cardiopulmonary resuscitation prognosis in CA patients.

Methods

We enrolled 52 in- or out-of-hospital CA patients, with 47 healthy volunteers as the control group (CG). Blood samples were taken for IMA and MDA measurement at the beginning or within 5 min of commencement of CPR. The patients were classified according to the Glasgow Outcome Score (GOS) into a poor outcome group (POG) and a good outcome group (GOG).

Results

Mean IMA levels were higher in POG (0.25 ± 0.07 ABSU) than in GOG (0.19 ± 0.07 ABSU, p = 0.002) and also than CG (0.16 ± 0.04 ABSU, p = 0.0001). The IMA levels were not significantly higher in GOG than in CG (p = 0.32). The mean MDA levels in POG (0.77 ± 0.27 nmol/ml) were comparable to the levels in GOG (0.75 ± 0.18 nmol/ml, p > 0.05), but were significantly higher than in CG (0.60 ± 0.15 nmol/ml, p = 0.001). MDA levels were not significantly higher in GOG than in CG (p = 0.06). The optimum cut-off point for IMA maximizing sensitivity and specificity was 0.235 ABSU, with sensitivity of 65.8% and specificity of 78.6%. The corresponding +PV and −PV were 85.3% and 45.8%, respectively.

Conclusion

In conclusion, though the result may not be applied clinically in every patient, the ischemia-modified albumin may be a valuable prognostic marker in cardiac arrest patients following CPR.     

Randomised study of hypertonic saline infusion during resuscitation from out-of-hospital cardiac arrest

Aim of the study

Animal models of hypertonic saline infusion during cardiopulmonary resuscitation (CPR) improve survival, as well as myocardial and cerebral perfusion during CPR. We studied the effect of hypertonic saline infusion during CPR (Guidelines 2000) on survival to hospital admission and hospital discharge, and neurological outcome on hospital discharge.

Methods

The study was performed by the EMS of Bonn, Germany, with ethical committee approval. Study inclusion criteria were non-traumatic out-of-hospital cardiac arrest, aged 18–80 years, and given of adrenaline (epinephrine) during CPR. Patients were randomly infused 2 ml kg⁻¹ HHS (7.2% NaCl with 6% hydroxyethyl starch 200,000/0.5 [HES]) or HES over 10 min.

Results

203 patients were randomised between May 2001 and June 2004. After HHS infusion, plasma sodium concentration increased significantly to 162 ± 36 mmol l⁻¹ at 10 min after infusion and decreased to near normal (144 ± 6 mmol l⁻¹) at hospital admission. Survival to hospital admission and hospital discharge was similar in both groups (50/100 HHS vs. 49/103 HES for hospital admission, 23/100 HHS vs. 22/103 HES for hospital discharge). There was a small improvement in neurological outcome in survivors on discharge (cerebral performance category 1 or 2) in the HHS group compared to the HES group (13/100 HHS vs. 5/100 HES, p < 0.05, odds-ratio 2.9, 95% confidence interval 1.004–8.5).

Conclusion

Hypertonic saline infusion during CPR using Guidelines 2000 did not improve survival to hospital admission or hospital discharge. There was a small improvement with hypertonic saline in the secondary endpoint of neurological outcome on discharge in survivors. Further adequately powered studies using current guidelines are needed.     

Does Dual Operator CPR help minimize interruptions in chest compressions?

Aims

Basic Life Support Guidelines 2005 emphasise the importance of reducing interruptions in chest compressions (no-flow duration) yet at the same time stopped recommending Dual Operator CPR. Dual Operator CPR (where one rescuer does ventilations and one chest compressions) could potentially minimize no-flow duration compared to Single Operator CPR. This study aims to determine if Dual Operator CPR reduces no-flow duration compared to Single Operator CPR.

Methodology

This was a prospective randomised controlled crossover trial. Medical students were randomised into ‘Dual Operator’ or ‘Single Operator’ CPR groups. Both groups performed 4 min of CPR according to their group allocation on a resuscitation manikin before crossing over to perform the other technique one week later.

Results

Fifty participants were recruited. Dual Operator CPR achieved slightly lower no-flow durations than the Single Operator CPR (28.5% (S.D. = 3.7) versus 31.6% (S.D. = 3.6), P ≤ 0.001). Dual Operator CPR was associated with slightly more rescue breaths per minute (4.9 (S.D. = 0.5) versus 4.5 (S.D. = 0.5), P = 0.009. There was no difference in compression depth, compression rate, duty cycle, rescue breath flow rate or rescue breath volume.

Conclusions

Dual Operator CPR with a compression to ventilation rate of 30:2 provides marginal improvement in no-flow duration but CPR quality is otherwise equivalent to Single Operator CPR. There seems little advantage to adding teaching on Dual Operator CPR to lay/trained first responder CPR programs.     

The utility of the HeartSaver Sticker for maintaining correct hand position during chest compressions

Background

The importance of attaining correct hand position in cardiopulmonary resuscitation (CPR) instruction has not been emphasized as much as the significance of the compression performance. Study Objectives: This pilot study was performed to investigate the utility of a HeartSaver Sticker for maintaining correct hand position during chest compressions.

Methods

Fifty-one sophomore college students, training to become emergency medical technicians, were recruited. The students, having no previous experience using HeartSaver stickers, participated in this prospective, randomized simulation-based controlled study, which consisted of two groups: 1) with sticker (n = 26), 2) without sticker (n = 25). The 4 × 4-cm HeartSaver sticker marked with both vertical and horizontal center lines was used in this study. Proper sticker placement was such that the vertical line coincided with the mid-sternum of the chest, and the horizontal line aligned with the nipples. Participants performed adult basic life support by single rescuer according to the 2005 American Heart Association resuscitation guidelines. Skill assessment was also performed by these guidelines.

Results

Group 1 participants placed the HeartSaver sticker on the correct landmark within 10 s of approaching the model. The compression rate and depth were not significantly different between the two groups. However, significant improvement in correct hand position was noticed when using the HeartSaver sticker. Correct hand position was 97.1% ± 7.4% in group 1 and 85.9% ± 21.5% in group 2 (p = 0.002).

Conclusion

The HeartSaver sticker was useful in maintaining correct hand position during the single-rescuer CPR scenario because it provided easy recognition of that position when compressing after ventilations.     

Effects of bone marrow mesenchymal stem cells in a rat model of myocardial infarction

Aim

Infusion of bone marrow mesenchymal stem cells (MSCs) improves myocardial function following myocardial infarction (MI). The mechanisms, however, remain controversial. This study was to investigate changes of MSCs in vivo after administration into myocardial infarcted rats. Our hypothesis was that MSCs might differentiate into contractile myocytes and improve myocardial function in vivo.

Methods

MI was induced in 21 Sprague–Dawley rats by ligation of the left anterior descending artery. One week after ligation, 18 rats were randomized to receive MSCs labeled with PKH26 in a phosphate buffer solution (PBS) by direct injection into the infarcted myocardium. The remaining 3 rats received PBS alone as placebo. An additional 3 non-ligated rats served as a normal group to obtain normal myocytes.

Results

Every week for 6 weeks, hearts from 3 rats injected with MSCs were harvested to observe single cardiomyocytes. Although each week numerous round MSCs were found in the hearts of animals treated with MSCs, beating cardiomyocyte-like cells labeled with PKH26 were observed at the sixth week. The contractility of cardiomyocyte-like cells was the same to that of the unlabeled contractile native cardiomyocytes at the sixth week and that of the normal group (10.71 ± 1.59 vs. 11.09 ± 3.42 vs. 11.21 ± 2.16, p > 0.05). The contractility of cardiomyocyte-like cells was greater than cells both from the first week (10.71 ± 1.59 vs. 7.37 ± 3.47, p < 0.01) and the second week (10.71 ± 1.59 vs. 8.08 ± 3.11, p < 0.05) which was associated with significantly increased ejection fraction.

Conclusions

MSCs can differentiate into beating cardiomyocytes in a rat model of MI and improve myocardial function.     

Coronary perfusion pressure during external chest compression in pseudo-EMD, comparison of systolic versus diastolic synchronization

Background

The fraction of cardiac arrest patients presenting with pulseless electrical activity is increasing, and it is likely that many of these patients have pseudo-electromechanical dissociation (P-EMD), a state in which there is residual cardiac contraction without a palpable pulse. The efficacy of cardiopulmonary resuscitation (CPR) with external chest compression synchronized with the P-EMD cardiac systole and diastole has not been fully evaluated.

Hypothesis

During external chest compression in P-EMD, the coronary perfusion pressure (CPP) will be greater with systolic synchronization compared with diastolic phase synchronization.

Methods

A porcine model of P-EMD induced by progressive hypoxia with peak aortic pressures targeted to 50 mmHg was used. CPR chest compressions were performed by either load distributing band or vest devices. Paired 10 s intervals of systolic and diastolic synchronization were performed randomly during P-EMD, and aortic, right atrial and CPP were compared.

Results

Stable P-EMD was achieved in 8 animals, with 2.6 ± 0.5 matched synchronization pairs per animal. Systolic synchronization was association with increases in relaxation phase aortic pressure (41.7 ± 8.9 mmHg vs. 36.9 ± 8.2 mmHg), and coronary perfusion pressure (37.6 ± 11.7 mmHg vs. 30.2 ± 9.6 mmHg). Diastolic synchronization was associated with an increased right atrial pressure (6.7 ± 4.1 mmHg vs. 4.1 ± 5.7 mmHg).

Conclusion

During P-EMD, synchronization of external chest compression with residual cardiac systole was associated with higher CPP compared to synchronization with diastole.     

Sodium nitroprusside enhanced cardiopulmonary resuscitation (SNPeCPR) improves vital organ perfusion pressures and carotid blood flow in a porcine model of cardiac arrest

Purpose of the study

To describe a new method of CPR that optimizes vital organ perfusion pressures and carotid blood flow. We tested the hypothesis that a combination of high dose sodium nitroprusside (SNP) as well as non-invasive devices and techniques known independently to enhance circulation would significantly improve carotid blood flow (CBF) and return of spontaneous circulation (ROSC) rates in a porcine model of cardiac arrest.

Methods

15 isofluorane anesthetized pigs (30 ± 1 kg), after 6 min of untreated ventricular fibrillation, were subsequently randomized to receive either 15 min of standard CPR (S-CPR) (8 animals) or 5 min epochs of S-CPR followed by active compression–decompression (ACD) + inspiratory impedance threshold device (ITD) CPR followed by ACD + ITD + abdominal binding (AB) with 1 mg of SNP administered at minutes 2, 7, 12 of CPR (7 animals). Primary endpoints were CBF and ROSC rates. ANOVA and Fisher's exact test were used for comparisons.

Results/conclusion

There was significant improvement in the hemodynamic parameters in the SNP animals. ROSC was achieved in 7/7 animals that received SNP and in 2/8 in the S-CPR (p = 0.007). CBF and end tidal CO₂ (ETCO₂) were significantly higher in the ACD + ITD + AB + SNP (SNPeCPR) animals during CPR. Bolus doses of SNP, when used in conjunction with ACD + ITD + AB CPR, significantly improve CBF and ROSC rates compared to S-CPR.     

Lung-protective mechanical ventilation does not protect against acute kidney injury in patients without lung injury at onset of mechanical ventilation

Introduction

Preclinical and clinical studies suggest that mechanical ventilation contributes to the development of acute kidney injury (AKI), particularly in the setting of lung-injurious ventilator strategies.

Objective

To determine whether ventilator settings in critically ill patients without acute lung injury (ALI) at onset of mechanical ventilation affect the development of AKI.

Design, Setting, and Patients

Secondary analysis of a randomized controlled trial (N = 150), comparing conventional tidal volume (V_T, 10 mL/kg) with low tidal volume (V_T, 6 mL/kg) mechanical ventilation in critically ill patients without ALI at randomization. During the first 5 days of mechanical ventilation, the RIFLE class was determined daily, whereas neutrophil gelatinase–associated lipocalin and cystatin C levels were measured in plasma collected on days 0, 2, and 4.

Results

Eighty-six patients had no AKI at inclusion, and 18 patients (21%) subsequently developed AKI, but without significant difference between ventilation strategies. (Cumulative hazard, 0.26 vs 0.23; P = .88.) The courses of neutrophil gelatinase–associated lipocalin and cystatin C plasma levels did not differ significantly between randomization groups.

Conclusion

In the present study in critically patients without ALI at onset of mechanical ventilation, lower tidal volume ventilation did not reduce the development or worsening of AKI compared with conventional tidal volume ventilation.     

Basic life support with four different compression/ventilation ratios in a pig model: The need for ventilation

Background

During cardiac arrest the paramount goal of basic life support (BLS) is the oxygenation of vital organs. Current recommendations are to combine chest compressions with ventilation in a fixed ratio of 30:2; however the optimum compression/ventilation ratio is still debatable. In our study we compared four different compression/ventilation ratios and documented their effects on the return of spontaneous circulation (ROSC), gas exchange, cerebral tissue oxygenation and haemodynamics in a pig model.

Methods

Study was performed on 32 pigs under general anaesthesia with endotracheal intubation. Arterial and central venous lines were inserted. For continuous cerebral tissue oxygenation a Licox^® PtiO₂ probe was implanted. After 3 min of cardiac arrest (ventricular fibrillation) animals were randomized to a compression/ventilation-ratio 30:2, 100:5, 100:2 or compressions-only. Subsequently 10 min BLS, Advanced Life Support (ALS) was performed (100%O₂, 3 defibrillations, 1 mg adrenaline i.v.). Data were analyzed with 2-factorial ANOVA.

Results

ROSC was achieved in 4/8 (30:2), 5/8 (100:5), 2/8 (100:2) and 0/8 (compr-only) pigs. During BLS, PaCO₂ increased to 55 mmHg (30:2), 68 mmHg (100:5; p = 0.0001), 66 mmHg (100:2; p = 0.002) and 72 mmHg (compr-only; p < 0.0001). PaO₂ decreased to 58 mmg (30:2), 40 mmHg (100:5; p = 0.15), 43 mmHg (100:2; p = 0.04) and 26 mmHg (compr-only; p < 0.0001). PtiO₂ baseline values were 12.7, 12.0, 11.1 and 10.0 mmHg and decreased to 8.1 mmHg (30:2), 4.1 mmHg (100:5; p = 0.08), 4.3 mmHg (100:2; p = 0.04), and 4.5 mmHg (compr-only; p = 0.69).

Conclusions

During BLS, a compression/ventilation-ratio of 100:5 seems to be equivalent to 30:2, while ratios of 100:2 or compressions-only detoriate peripheral arterial oxygenation and reduce the chance for ROSC.     

Comparison of different video laryngoscopes for emergency intubation in a standardized airway manikin with immobilized cervical spine by experienced anaesthetists. A randomized, controlled crossover trial

Background

The aim of the present study was to evaluate whether different video laryngoscopes (VLs) facilitate endotracheal intubation (ETI) faster or more secure than conventional laryngoscopy in a manikin with immobilized cervical spine.

Methods

After local ethics board approval, a standard airway manikin with cervical spine immobilization by means of a standard stiff collar was placed on a trauma stretcher. We compared times until glottic view, ETI, cuff block and first ventilation were achieved, and verified the endotracheal tube position, when using Macintosh laryngoscope, Glidescope Ranger, Storz C-MAC, Ambu Pentax AWS, Airtraq, and McGrath Series5 VLs in randomized order. Wilcoxon signed-rank test and McNemar's test were used for statistical analysis; p < 0.05 was considered as significant.

Results

Twenty-three anaesthetists (mean age 32.1 ± 4.9 years, mean experience in anaesthesia of 6.9 ± 4.8 years) routinely involved in the management of multitrauma patients participated. The primary study end point, time to first effective ventilation, was achieved fastest when using Macintosh laryngoscope (21.0 ± 7.6 s) and was significantly slower with all other devices (Airtraq 33.2 ± 23.9 s, p = 0.002; Pentax AirwayScope 32.4 ± 14.9 s, p = 0.001; Storz C-MAC 34.1 ± 23.9 s, p < 0.001; McGrath Series5 101.7 ± 108.3 s, p < 0.001; Glidescope Ranger 46.3 ± 59.1 s, p = 0.001). Overall success rates were highest when using Macintosh, Airtraq and Storz C-MAC devices (100%), and were lower in Ambu Pentax AWS and Glidescope Ranger (87%, p = 0.5) and in McGrath Series5 device (72.2%, p = 0.063).

Conclusion

When used by experienced anaesthesiologists, video laryngoscopes did not facilitate endotracheal intubation in this model with an immobilized cervical spine in a faster or more secure way than conventional laryngoscopy. However, data was gathered in a standardized model and further studies in real trauma patients are desirable to verify our findings.     

Is there any room for shortening hands-off time further when using an AED?

Background

Automated external defibrillators (AEDs) play a very important role in out-of-hospital cardiopulmonary resuscitation (CPR). The mandatory hands-off time imposed by current AEDs is not short enough to bring about the full benefits of rapid defibrillation with an AED into light. The aim of this study is to examine whether a change in the process of charging the capacity and removing explanations from the prompts of the AEDs shortens hands-off time.

Methods

The operating steps and the voice prompts of the current AEDs were reviewed and the time intervals between the steps and the voice prompts were measured. We modified an AED to fully precharge the capacitor and to contain more concise voice prompts.

Results

We had 42 expert rescuers and 50 lay-person rescuers perform 2-rescuer CPR with the modified AED and the old AED, respectively. Using the modified AED significantly reduced hands-off times by 9.95 s (95% CI: 9.67–10.23) in 2-rescuer CPR and by 10.68 s (95% CI: 9.75–11.61) in 1-rescuer CPR (p < 0.001).

Conclusion

Full precharging of the capacitor and exclusion of explanations from the voice prompts of AEDs can shorten the hands-off time in both 1 and 2-rescuer CPR.     

Electrocardiographic changes during therapeutic hypothermia

Aims

Induced mild therapeutic hypothermia (MTH) is an effective treatment to improve outcome after out-of-hospital resuscitation. Adverse events are rare, but arrhythmias and bleeding complications have been reported. So far, only few data about electrocardiographic changes and associated events have been reported.

Methods

Between 6/2005 and 3/2011, 109 comatose survivors of out-of-hospital cardiac arrest admitted to our institution underwent MTH. In an observational single-center study, we analyzed preclinical course, electrocardiographic changes, arrhythmias, laboratory parameters and complication rates before, during and after MTH.

Results

MTH led to a significant decrease of heart rate (85.0 ± 23.3 min⁻¹ at admission; 59.1 ± 20.5 min⁻¹ during, p < 0.01 and 63.1 ± 19.2 after hypothermia p < 0.05) a significant prolongation of PR (0.17 ± 0.04 s before, 0.18 ± 0.05 s during, p < 0.05; and 0.17 ± 0.04 s after hypothermia, p < 0.01) and QTc intervals (0.47 ± 0.05 s before, 0.49 ± 0.05 s during, p < 0.01; and 0.46 ± 0.05 s after hypothermia, p < 0.01). Two patients developed ventricular fibrillation during hypothermia, both had an acute myocardial infarction. No significant MTH related changes in electrolytes or coagulation parameters were observed. Major bleeding complications occurred in four cases (3.7%) with a trend towards more bleedings after use of preclinical thrombolysis (21.4% with to 6.4% without thrombolysis, p = 0.057). We did not find increased risk for bleeding complications in patients with double platelet inhibition after PCI (14.3% compared to 9.5% without PCI, p = 0.63) compared to those without PCI.

Conclusions

Under strict clinical and laboratory parameter control, induced mild therapeutic hypothermia can be applied to most patients after out-of-hospital cardiac arrest with no increased risk for arrhythmias despite significant electrocardiographic changes.     

Sodium sulfide prevents water diffusion abnormality in the brain and improves long term outcome after cardiac arrest in mice

Aim of the study

Sudden cardiac arrest (CA) is one of the leading causes of death worldwide. Previously we demonstrated that administration of sodium sulfide (Na₂S), a hydrogen sulfide (H₂S) donor, markedly improved the neurological outcome and survival rate at 24 h after CA and cardiopulmonary resuscitation (CPR) in mice. In this study, we sought to elucidate the mechanism responsible for the neuroprotective effects of Na₂S and its impact on the long-term survival after CA/CPR in mice.

Methods

Adult male mice were subjected to potassium-induced CA for 7.5 min at 37 °C whereupon CPR was performed with chest compression and mechanical ventilation. Mice received Na₂S (0.55 mg kg⁻¹ i.v.) or vehicle 1 min before CPR.

Results

Mice that were subjected to CA/CPR and received vehicle exhibited a poor 10-day survival rate (4/12) and depressed neurological function. Cardiac arrest and CPR induced abnormal water diffusion in the vulnerable regions of the brain, as demonstrated by hyperintense diffusion-weighted imaging (DWI) 24 h after CA/CPR. Extent of hyperintense DWI was associated with matrix metalloproteinase 9 (MMP-9) activation, worse neurological outcomes, and poor survival rate at 10 days after CA/CPR. Administration of Na₂S prevented the development of abnormal water diffusion and MMP-9 activation and markedly improved neurological function and long-term survival (9/12, P < 0.05 vs. Vehicle) after CA/CPR.

Conclusion

These results suggest that administration of Na₂S 1 min before CPR improves neurological function and survival rate at 10 days after CA/CPR by preventing water diffusion abnormality in the brain potentially via inhibiting MMP-9 activation early after resuscitation.     

Transfusion of Packed Red Blood Cells is Not Associated with Improved Central Venous Oxygen Saturation or Organ Function in Patients with Septic Shock

Background

The exact role of packed red blood cell (PRBC) transfusion in the setting of early resuscitation in septic shock is unknown.

Study Objective

To evaluate whether PRBC transfusion is associated with improved central venous oxygen saturation (ScvO₂) or organ function in patients with severe sepsis and septic shock receiving early goal-directed therapy (EGDT).

Methods

Retrospective cohort study (n = 93) of patients presenting with severe sepsis or septic shock treated with EGDT.

Results

Thirty-four of 93 patients received at least one PRBC transfusion. The ScvO₂ goal > 70% was achieved in 71.9% of the PRBC group and 66.1% of the no-PRBC group (p = 0.30). There was no difference in the change in Sequential Organ Failure Assessment (SOFA) score within the first 24 h in the PRBC group vs. the no-PRBC group (8.6–8.3 vs. 5.8–5.6, p = 0.85), time to achievement of central venous pressure > 8 mm Hg (732 min vs. 465 min, p = 0.14), or the use of norepinephrine to maintain mean arterial pressure > 65 mm Hg (81.3% vs. 83.8%, p = 0.77).

Conclusions

In this study, the transfusion of PRBC was not associated with improved cellular oxygenation, as demonstrated by a lack of improved achievement of ScvO₂ > 70%. Also, the transfusion of PRBC was not associated with improved organ function or improved achievement of the other goals of EGDT. Further studies are needed to determine the impact of transfusion of PRBC within the context of early resuscitation of patients with septic shock.     

Quality of CPR performed by trained bystanders with optimized pre-arrival instructions

Objective

Telephone-CPR (T-CPR) can increase initiation of bystander CPR. We wanted to study if quality oriented continuous T-CPR would improve CPR performance vs. standard T-CPR.

Method

Ninety-five trained rescuers aged 22–69 were randomized to standard T-CPR or experimental continuous T-CPR (comprises continuous instructions, questions and encouragement). They were instructed to perform 10 min of chest compressions-only on a manikin, which recorded CPR performance in a small, confined kitchen. Three video-cameras captured algorithm time data, CPR technique and communication. Demography and training experience were captured during debriefing.

Results

Participants receiving continuous T-CPR delivered significantly more chest compressions (median 1000 vs. 870 compressions, p = 0.014) and compressed more frequently to a compression rate between 90 and 120 min⁻¹ (median 87% vs. 60% of compressions, p < 0.001), compared to those receiving standard T-CPR. This also resulted in less time without compressions after CPR had started (median 12 s vs. 64 s, p < 0.001), but longer time interval from initiating contact with dispatcher to first chest compression (median 144 s vs. 84 s, p < 0.001). There was no difference in chest compression depth (mean 47 mm vs. 48 mm, p = 0.90) or in demography, education and previous CPR training between the groups.

Conclusion

In our simulated scenario with CPR trained lay rescuers, experimental continuous T-CPR gave better chest compression rate and less hands-off time during CPR, but resulted in delayed time to first chest compression compared to standard T-CPR instructions.