Gabriel Putzer

LUCAS compared to manual cardiopulmonary resuscitation is more effective during helicopter rescue-a prospective, randomized, cross-over manikin study.

OBJECTIVE High-quality chest-compressions are of paramount importance for survival and good neurological outcome after cardiac arrest. However, even healthcare professionals have difficulty performing effective chest-compressions, and quality may be further reduced during transport. We compared a mechanical chest-compression device (Lund University Cardiac Assist System [LUCAS]; Jolife, Lund, Sweden) and manual chest-compressions in a simulated cardiopulmonary resuscitation scenario during helicopter rescue. METHODS Twenty-five advanced life support-certified paramedics were enrolled for this prospective, randomized, crossover study. A modified Resusci Anne manikin was employed. Thirty minutes of training was allotted to both LUCAS and manual cardiopulmonary resuscitation (CPR). Thereafter, every candidate performed the same scenario twice, once with LUCAS and once with manual CPR. The primary outcome measure was the percentage of correct chest-compressions relative to total chest-compressions. RESULTS LUCAS compared to manual chest-compressions were more frequently correct (99% vs 59%, P < .001) and were more often performed correctly regarding depth (99% vs 79%, P < .001), pressure point (100% vs 79%, P < .001) and pressure release (100% vs 97%, P = .001). Hands-off time was shorter in the LUCAS than in the manual group (46 vs 130 seconds, P < .001). Time until first defibrillation was longer in the LUCAS group (112 vs 49 seconds, P < .001). CONCLUSIONS During this simulated cardiac arrest scenario in helicopter rescue LUCAS compared to manual chest-compressions increased CPR quality and reduced hands-off time, but prolonged the time interval to the first defibrillation. Further clinical trials are warranted to confirm potential benefits of LUCAS CPR in helicopter rescue.

Near-infrared spectroscopy during cardiopulmonary resuscitation of a hypothermic polytraumatised cardiac arrest patient.

A helicopter emergency team located a 48-year old male olytraumatised backcountry skier 10 h after having fallen down pproximately 100 m over steep terrain lying on avalanche debris. n-site, the Glasgow Coma Scale (GCS) score was 3, the resiratory rate was 24 min−1 and core body temperature 20.0 ◦C, easured epitympanically. The patient’s trachea was intubated nd he was transported to our Level 1 hospital by helicopter. fter take-off, ventricular fibrillation (VF) developed and continous cardiopulmonary resuscitation (CPR) was initiated. In the mergency room the patient was monitored with near–infrared pectroscopy (NIRS; INVOSTM System, Somanetics Inc., Troy, MI), sing a single probe on the right forehead. Additionally, he as monitored with ECG, invasive blood pressure measurement, ulse oximetry, and transoesophageal echocardiography (TEE; E33, Philips, Amsterdam, Netherlands). To rewarm the patient eno-arterial extracorporeal membrane oxygenation (ECMO; PBS, edtronic, Minneapolis, MN) was initiated employing a femoral ccess 80 min after hospital admission.1 After rewarming, with he patient still on ECMO support, arterial blood pressure was nstable, despite vasopressor (adrenaline 0.1–0.2 mcg kg−1 min−1 nd noradrenaline 0.02 mcg kg−1 min−1) and fluid administration overall 5.5 L lactated Ringer, 3.5 L saline, 30 fresh frozen plasma nits and 17 packed red blood cell units; the target haemoglobin as >8 mg dL−1). Immediate computed tomography (CT) revealed evere thoracic trauma with bilateral multiple rib fractures, leftided pneumothorax, pneumomediastinum, ruptured diaphragm nd pericardial tear. In addition, a triple pelvic fracture was further omplicated by massive internal iliac artery haemorrhage into the etroperitoneal space. The patient died approximately 4.5 h after dmission while it was attempted to stop the retroperitoneal haemrrhage angiographically. This is the first report of cerebral NIRS monitoring during PR in a hypothermic cardiac arrest patient. In contrast to previusly described scarcely detectable NIRS readings during cardiac rrest with CPR,2 we recorded remarkably high NIRS values which ere probably due to the deep hypothermia, which is thought o decrease brain tissue oxygen consumption by approximately % ◦C−1.3 NIRS values varied between 40 and 60% during CPR and eached 80% after restoration of normal systemic perfusion through CMO (Fig. 1). Although there are multiple factors that render IRS interpretation challenging, e.g. haemoglobin concentration, erebral venous drainage and oxygen consumption, our NIRS data orrelated properly with chest compression efficiency and interuptions of chest compressions for cannula placement. Only recently has this highly promising technique been used uring CPR.4 Prospective NIRS measurements during CPR could ave important clinical implications by supplying rescuers with 2

Surviving 6 days in a crevasse

In August, 2012, a 70-year-old-man fell 10 m into a crevasse (10 m depth, 1 m width) while crossing a glacier alone at 3000 m in the Austrian Alps. He was immediately wet up to his waist and gloves with no possibility of self-rescue. He was healthy, fi t, and was not taking any medication. He had a history of two leg fractures many years ago but otherwise an uneventful medical history. He had hiking equipment including gloves, hat, and some food, but was without specifi c glacier equipment such as crampons, iceaxe, and rope. In the crevasse there was some visible daylight and he sat down on his backpack. There was no cellular network coverage and his mobile phone battery was soon depleted. On the basis of the distance to the closest mountain huts he estimated that hikers could have been in his vicinity between 1000 h and 1600 h daily, during which time he periodically shouted for help. To conserve body heat he covered himself with rescue foil (200 cm by 135 cm) (fi gure). He rationed his food to a few biscuits and one row of chocolate daily (800 kJ per day), and drank water dripping from the ice, but he became increasingly thirsty. He reported that he had lost hope of survival on the fourth day, but resisted panicking. On the sixth day, hikers heard his call and a medical helicopter and rescue team were mobilised. Our patient was winched up from the crevasse and fl own to a local hospital. On assessment, his Glasgow-coma-scale score was 15, heart-rate 85 per min in sinus rhythm, blood pressure 120/70 mm Hg, body-core temperature meas ured epitympanically 33·5°C, serum sodium 130 mmol/L, creatinine 173·3 μmol/L, urea 90·4 mmol/L, creatine kinase 2·942 U/L, myoglobin 2·013 μg/L, uric acid 1058·7 μmol/L, glucose 8·9 mmol/L, Lancet 2013; 381: 506

Monitoring of brain oxygenation during hypothermic CPR – A prospective porcine study

BACKGROUND AND AIM Limited data are available concerning the impact of CPR interventions on cerebral oxygenation during hypothermic cardiac arrest. We therefore studied cerebral perfusion pressure (CPP), brain tissue oxygen tension (PbtO2), cerebral venous oxygen saturation (ScvO2) and regional cerebral oxygen saturation (rSO2) in an animal model of hypothermic CPR. We also assessed the correlation between rSO2 and CPP, PbtO2 and ScvO2 to clarify whether near-infrared spectroscopy (NIRS) may be used to non-invasively monitor changes in cerebral oxygenation during hypothermic CPR. METHODS Nine pigs were surface-cooled to a core temperature of 28°C and underwent a period of asphyxia before cardiac arrest was induced. After 2min of untreated cardiac arrest they were resuscitated for 45min. CPP, PbtO2, ScvO2 and rSO2 were monitored after periods of stable external chest compression, a short interruption of CPR and after epinephrine administration. RESULTS During external chest-compressions before adrenalin administration CPP, PbtO2, ScvO2 and rSO2 increased in parallel and changes in rSO2 closely correlated with changes in CPP (r=.844; p<.001) and ScvO2 (r=.868; p<.001). After adrenaline administration CPP and PbtO2 increased, ScvO2 decreased and rSO2 values did not change and there was no significant correlation between rSO2 and CPP, PbtO2, or ScvO2. CONCLUSION In this animal model of hypothermic cardiac arrest adrenaline was associated with an increase in global cerebral oxygen extraction despite an increase in CPP. Discrepancies in the time course of PbtO2 and ScvO2 suggest differences in regional oxygen metabolism after adrenalin. rSO2 values correlated closely with CPP and ScvO2 only during periods of external chest compression without adrenaline administration.

Pulmonary edema after complete avalanche burial

A48-year-old female backcountry skier was completely buried by an avalanche 50 cm under snow and was extricated by her companions after *20–30 min. At arrival of the emergency physician by helicopter, the victim was just extricated, agitated, and in respiratory distress. She had a Glasgow Coma Scale (GCS) of 14, pulse oximetry of 86%, heart rate of 130 min , and epitympanic core body temperature of 32.0 C. (Gilbert Metraux, Crissier, Switzerland) The patient was placed into a thermo-rescue-bag, received 6 Lmin 1 oxygen by facemask and was transported to the hospital by helicopter. The patient arrived in the emergency room 31 min after the beginning of prehospital treatment. There she had a GCS of 15, central cyanosis, tachypnea and coughing, and a pulse oximetry of 92% (with 6 Lmin 1 oxygen), heart rate of 120 min , blood pressure of 120/70mmHg and an epitympanic core body temperature of 33.8 C. (Ototemp 3000 Special Duty, Exergen, Watertown, MA) According to the Innsbruck emergency room algorithm, a head-trunk CT-scan was performed, which showed bilateral alveolar fluid accumulation consistent with lung contusions and pulmonary edema. No other pathologies were detected. At 40 min postadmission, the patient became severely dyspnoic and showed clinical signs of pulmonary edema. After anesthetization and endotracheal intubation, the patient was ventilated with an inspiratory oxygen fraction (Fio2) of 1.0 and positive endexpiratory pressure (PEEP) of 10 mbar. (1 mbar = 1.02 cm H2O) Arterial oxygen partial pressure was 73.6 mmHg and arterial carbon dioxide partial pressure was 56.2 mmHg. While there was no evidence for cardiac dysfunction, a chest x-ray showed bilateral pulmonary edema (Fig. 1A). The patient was transferred to the ICU and rewarmed within 2 hours by external forced air rewarming blankets. Within 3 hours, the oxygenation improved markedly and Fio2 was reduced to 0.35. After 8 hours of ventilation, the patient was breathing spontaneously on continuous positive airway pressure (CPAP). After 16 h, she was extubated and breathing sufficiently with supplemental oxygen and intermittent CPAP therapy; the chest x-ray revealed no residual pulmonary edema. On day three, respiratory function was stable and oxygenation and chest x-ray (Fig. 1B) were normal. The patient was discharged from the hospital, and she recovered quickly at home. The patient was athletic and her medical history was unremarkable, apart from the avalanche burial. Pulmonary edema has been reported in a 51-year-old female who sustained complete avalanche burial for approximately 20 min with a core body temperature of 32 C at

Manual versus Mechanical Chest Compressions on Surfaces of Varying Softness with or without Backboards: A Randomized, Crossover Manikin Study

BACKGROUND Chest compression quality is decisive for overall outcome after cardiac arrest. Chest compression depth may decrease when cardiopulmonary resuscitation (CPR) is performed on a mattress, and the use of a backboard does not necessarily improve compression depth. Mechanical chest compression devices may overcome this problem. OBJECTIVES We sought to investigate the effectiveness of manual chest compressions both with and without a backboard compared to mechanical CPR performed on surfaces of different softness. METHODS Twenty-four advanced life support (ALS)-certified rescuers were enrolled. LUCAS2 (Physio-Control, Redmond, WA) delivers 52 ± 2 mm deep chest compressions and active decompressions back to the neutral position (frequency 102 min(-1); duty cycle, 50%). This simulated CPR scenario was performed on a Resusci-Anne manikin (Laerdal, Stavanger, Norway) that was lying on 3 different surfaces: 1) a concrete floor, 2) a firm standard mattress, and 3) a pressure-relieving mattress. Data were recorded by the Laerdal Skill Reporting System. RESULTS Manual chest compression with or without a backboard were performed correctly less often than mechanical chest compressions (floor: 33% [interquartile range {IQR}, 27-48%] vs. 90% [IQR, 86-94%], p < 0.001; standard mattress: 32% [IQR, 20-45%] vs. 27% [IQR, 14-46%] vs. 91% [IQR, 51-94%], p < 0.001; and pressure-relieving mattress 29% [IQR, 17-49%] vs. 30% [IQR, 17-52%] vs. 91% [IQR, 87-95%], p < 0.001). The mean compression depth on both mattresses was deeper with mechanical chest compressions (floor: 53 mm [range, 47-57 mm] vs. 56 mm [range, 54-57 mm], p = 0.003; standard mattress: 50 mm [range, 44-55 mm] vs. 51 mm [range, 47-55 mm] vs. 55 mm [range, 54-58 mm], p < 0.001; and pressure-relieving mattress: 49 mm [range, 44-55 mm] vs. 50 mm [range, 44-53 mm] vs. 55 mm [range, 55-56 mm], p < 0.001). In this ∼6-min scenario, the mean hands-off time was ∼15 to 20 s shorter in the manual CPR scenarios. CONCLUSIONS In this experimental study, only ∼30% of manual chest compressions were performed correctly compared to ∼90% of mechanical chest compressions, regardless of the underlying surface. Backboard use did not influence the mean compression depth during manual CPR. Chest compressions were deeper with mechanical CPR. The mean hands-off time was shorter with manual CPR.

Effects of Stomach Inflation on Cardiopulmonary Function and Survival During Hemorrhagic Shock: A Randomized, Controlled, Porcine Study

Background: Ventilation of an unprotected airway may result in stomach inflation. The purpose of this study was to evaluate the effect of clinically realistic stomach inflation on cardiopulmonary function during hemorrhagic shock in a porcine model. Methods: Pigs were randomized to a sham control group (n = 9), hemorrhagic shock (35 mL kg−1 over 15 min [n = 9]), and hemorrhagic shock combined with stomach inflation (35 mL kg−1 over 15 min and 5 L stomach inflation [n = 10]). Results: When compared with the control group, hemorrhagic shock (n = 9) increased heart rate (103 ± 11 vs. 146 ± 37 beats min−1; P = 0.002) and lactate (1.4 ± 0.5 vs. 4.0 ± 1.9 mmol L−1; P < 0.001), and decreased mean arterial blood pressure (81.3 ± 12.8 vs. 35.4 ± 8.1 mmHg; P < 0.001) and stroke-volume index (38.1 ± 6.4 vs. 13.6 ± 4.8 mL min−1 m−2; P < 0.001). Hemorrhagic shock combined with stomach inflation (n = 10) versus hemorrhagic shock only (n = 9) increased intra-abdominal pressure (27.0 ± 9.3 vs. 1.1 ± 1.0 mmHg; P < 0.001), and decreased stroke-volume index (9.9 ± 6.0 vs. 20.8 ± 8.5 mL min−1 m−2; P = 0.007), and dynamic respiratory system compliance (10.8 ± 4.5 vs. 38.1 ± 6.1 mL cmH2O−1; P < 0.001). Before versus after stomach evacuation during hemorrhagic shock, intra-abdominal pressure decreased (27.0 ± 9.3 vs. 9.8 ± 5.4 mmHg; P = 0.042). Survival in the sham control and hemorrhagic shock group was 9 of 9, respectively, and 3 of 10 after hemorrhagic shock and stomach inflation (P < 0.001). Conclusions: During hemorrhagic shock stomach inflation caused an abdominal compartment syndrome and thereby impaired cardiopulmonary function and aerobic metabolism, and increased mortality. Subsequent stomach evacuation partly reversed adverse stomach-inflation triggered effects.

Emergency Extracorporeal Life Support After Prolonged Out-of-Hospital Cardiac Arrest

PROLONGED RESUSCITATION EFFORTS in patients with out-of-hospital cardiac arrest (OHCA) are associated with survival rates of less than 3%. Transfer to a hospital for emergency extracorporeal life support (ECLS) generally is not recommended and rarely is used in these patients. The authors report a long-term survivor of prolonged OHCA treated with ECLS after 107 minutes of external chest compressions.

Apparent Cooling Rate of 7°C per Hour in an Avalanche Victim.

Avalanche victims can become hypothermic within 35 minutes of snow burial. However, reported cooling rates for avalanche victims are highly variable and it is poorly understood how much cooling is influenced by general factors (body composition, clothing, ambient conditions, duration of burial, and metabolism), unknown inter-individual factors or other phenomena (e.g., afterdrop). We report an apparent cooling rate of ∼7°C in ∼60 minutes in a healthy backcountry skier who was rewarmed with forced air and warm fluids and was discharged after 2 weeks without neurological sequelae.

Effects of head-up vs. supine CPR on cerebral oxygenation and cerebral metabolism – a prospective, randomized porcine study

BACKGROUND Recent studies have shown that during cardiopulmonary resuscitation (CPR) head-up position (HUP) as compared to standard supine position (SUP) decreases intracranial pressure (ICP) and increases cerebral perfusion pressure (CPP). The impact of this manoeuvre on brain oxygenation and metabolism is not clear. We therefore investigated HUP as compared to SUP during basic life support (BLS) CPR for their effect on brain oxygenation and metabolism. METHODS Twenty pigs were anaesthetized and instrumented. After 8 min of cardiac arrest (CA) pigs were randomized to either HUP or SUP and resuscitated mechanically for 20 min. Mean arterial pressure (MAP), ICP, CPP, cerebral regional oxygen saturation (rSO2) and brain tissue oxygen tension (PbtO2) were measured at baseline, after CA and every 5 min during CPR. Cerebral venous oxygen saturation (ScvO2) was measured at baseline, after CA and after 20 min of CPR. Cerebral microdialysis parameters, e.g. lactate/pyruvate ratio (L/P ratio) were taken at baseline and the end of the experiment. RESULTS ICP was significantly lower in HUP compared to SUP animals after 5 min (18.0 ± 4.5 vs. 24.1 ± 5.2 mmHg; p = 0.033) and 20 min (12.0 ± 3.4 vs. 17.8 ± 4.3 mmHg; p = 0.023) of CPR. Accordingly, CPP was significantly higher in the HUP group after 5 min (11.2 ± 9.5 vs. 1.0 ± 9.2 mmHg; p = 0.045) and 20 min (3.4 ± 6.4 vs. -3.8 ± 2.8 mmHg; p = 0.023) of CPR. However, no difference was found in rSO2, PbtO2, ScvO2 and L/P ratio between groups after 20 min of CPR. CONCLUSION In this animal model of BLS CPR, HUP as compared to SUP did not improve cerebral oxygenation or metabolism.