[Escalation and de-escalation concept for intensive care beds in hospitals reserved for COVID-19]. / Eskalations­/Deeskalationskonzept zur COVID-19-bedingten Freihaltung von Intensivkapazitäten an Kliniken.

BACKGROUND: Since the spread of Severe Acute Respiratory Syndrom Corona Virus 2 (SARS-CoV­2) in Germany, intensive care beds have been kept free for patients suffering from Corona Virus Disease (COVID-19). Also, after the number of infections had declined, intensive care beds were kept free prophylactically; however, the percentage of beds reserved for COVID-19 differ in the individual federal states in Germany. The aim of this article is to define a necessary clearance quota of intensive beds for COVID-19 patients in Germany. An escalation and de-escalation scheme was created for rising and falling numbers of infected patients. METHODS: Data from the COVID-19 resource board of the state of Baden-Württemberg, the daily situation report of the Robert Koch Institute (RKI), the register of COVID-19 intensive care beds of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI) as well as the daily report of COVID-19 Baden-Württemberg from April to November 2020 were used for the calculation. RESULTS: At the end of November 2020 approximately 13.5% of intensive care beds in Germany were used by COVID-19 patients. Of all persons tested positive for SARS-CoV­2, 1.5% were admitted to an intensive care unit. The hospitalization rate was 6% and the mean age of infected persons was 43 years. Based on these numbers hospitals are recommended to keep 10% of intensive care beds available for COVID-19 patients in the case of less than 35 new infections/100,000 in the catchment area, 20% should be kept free in case of an advanced warning level of 35 new infections/100,000 inhabitants and 30% for a critical limit of 50 new infections/100,000 inhabitants. Further internal hospital triggers, such as the occupancy of the intensive care beds with COVID-19 patients, should be considered. CONCLUSION: If the number of infections is low a general nationwide retention rate of more than 10% of intensive care beds for COVID-19 patients is not justified. Locally increasing numbers of infections require a local dynamic approach. If the number of infections increases, the free holding capacity should be increased according to a step by step concept in close coordination with the local health authorities and other internal hospital triggers. In order not to overwhelm hospital capacities in the event of local outbreaks, a corresponding relocation concept should be considered at an early stage.

[Provisioning of personal protective equipment in hospitals in preparation for a pandemic]. / Bevorratung persönlicher Schutzausrüstung in Kliniken zur Vorbereitung auf eine Pandemie.

BACKGROUND: At the beginning of the SARS-CoV­2 outbreak, personal protective equipment (PPE) was scarce worldwide, leading to the treatment of patients partially without sufficient protection for the medical personnel. In order to be prepared for a new epidemic or pandemic or a "second wave" of COVID-19 outbreak and to meet a renewed deficiency of PPE, considerations were made on how personnel and patients can be better protected by appropriate provisioning. OBJECTIVE: The aim of this study was to develop a tool to predict the necessary amount of PPE to be in stock at a transregional university hospital for a certain period of time during a pandemic. MATERIAL AND METHODS: The consumption of PPE needed for every patient was calculated based on the following data of the Ulm University Hospital: the total consumption of healthcare workers' PPE for April 2020 recorded by the materials management department and the number of patients suffering from COVID-19 and their treatment days. From the amount of PPE necessary for every patient in the intensive care unit (ICU) or in an infection ward, a PPE calculator was created in which the estimated amount of PPE can be calculated with the input variables "patients in intensive care unit", "patients in infection ward" and "treatment days". To validate the PPE calculator, the actual consumption of PPE for May 2020 at the Ulm University hospital was compared to the theoretically calculated demand by the PPE calculator. RESULTS: In April 2020 PPE consisting of 18 different items were kept in stock at Ulm University Hospital and in total 1,995,500 individual items were used. 22 intensive care patients with 257 nursing days and in the infection ward 39 patients with 357 nursing days were treated for COVID-19 disease, leading to a total of 603.2 man-days. A total of 34,550 KN95 masks, 1,558,780 gloves and 1100 goggles or protective visors were used, with a daily average of 49 NK95 masks and 2216 gloves required per ICU patient. In May 2020, 6 ICU patients and 19 patients in infection wards were treated for COVID-19 with 34 nursing days in intensive care and 201 nursing days in infection wards. The use of PPE material was 39% lower than in the previous month but in absolute terms 82% and on average 39% higher than calculated. CONCLUSION: The developed tool allows our hospital to estimate the necessary amount of PPE to be kept in stock for future pandemics. By taking local conditions into account this tool can also be helpful for other hospitals.

[Terrorist attack training exercise-What can be learned? : Baden-Württemberg counterterrorism exercise (BWTEX)]. / Terrorismusabwehrübung ­ Was können wir daraus lernen? : Baden-Württembergische Terrorismusabwehr Exercise (BWTEX).

BACKGROUND: There is a risk of terror attacks in the Federal Republic of Germany, which might increase in the future. A timely comprehensive strategy for treatment and care of a large number of casualties helps minimize chaos and improve the outcome of patients. Adequate training is vital for successful implementation of an emergency plan. Therefore, the effectiveness of training should be assessed and evaluated; however, data collection capabilities for training events are extremely limited, so that publications on the topic are almost impossible to find. OBJECTIVE: This study aimed to collect data from a simulated terrorist attack in order to draw conclusions from a clinical point of view concerning the improvement of preclinical and clinical management, taking interface problems into consideration. MATERIAL AND METHODS: On 19 October 2019 the Ministry of the Interior, Digitalization and Migration of Baden-Württemberg conducted a large-scale simulation of a terrorist attack in the city center of Constance, called the Baden-Württemberg counterterrorism exercise (BWTEX). The simulation included an explosion of a car bomb as well as the use of firearms by terrorists. The large scale of the simulation with the high number of participants in combination with close cooperation between military and civil forces was unprecedented. The police force, the armed forces, civil protection forces, air rescue teams and staff from Constance, Friedrichshafen and Sigmaringen regional hospitals in southwest Germany worked together to treat simulated injuries to victims of the attack. The following parameters were recorded when the injured patients arrived at the hospital: prehospital triage time, prehospital triage score, initial treatment and quality of documentation on site as well as triage time, triage score, injury severity scale (ISS) score based on the specified injury pattern, treatment, and quality of documentation on hospital arrival. RESULTS: Out of a total of 84 "injured patients" 55 were admitted to hospital and 80% were triaged at the scene. Injured patients of triage category 1 (TK1 red: life-threatening injury, immediate treatment) arrived at the hospital 198 ± 50 min after the attack, injured patients of triage category 2 (TK2 yellow: severely injured, urgent treatment) after 131 ± 44 min and injured patients of triage category 3 (TK3 green: slightly injured, non-urgent treatment) arrived after 157 ± 46 min. There was no significant difference in terms of arrival time at the hospital between the triage scores (r = 0.2) or between the ISS scores (r = 0.43). The authors assume that approximately 44% of TK1 patients would have died due to avoidable time delays. Prehospital medical documentation was insufficient in 78% and insufficient in 65% in the hospitals. CONCLUSION: A mass casualty incident resulting from a terrorist attack differs greatly from a conventional mass casualty incident. The scene of the attack has to be evacuated as quickly as possible, which means that a large number of patients arrive untreated at the nearest hospitals. The setting up of treatment facilities in city centers and areas close to the city seems to be counterproductive because the time delay may result in higher mortality rates of victims. The particularities of mass casualties caused by a terrorist attack have to be incorporated into terrorist attack training.

[Terror attacks : Recommendations for cooperation between police, hospitals and non-police security services]. / Lebensbedrohliche Einsatzlagen : Handlungsempfehlung zur Zusammenarbeit zwischen Polizei, Kliniken und nichtpolizeilicher Gefahrenabwehr.

BACKGROUND: The risk of terrorist attacks in the Federal Republic of Germany is present and is currently increasing. Publicly funded acute care hospitals and their owners are involved in disaster control as part of their remit and are responsible for taking comprehensive precautions to ensure their operational capability in the event of disasters. This mandate must also be ensured in the event of terrorist attacks and amok incidents. For this purpose, an optimal cooperation between preclinical and clinical care is indispensable. AIM: Recommended actions for collaboration between nonclinical and clinical planning to manage a mass casualty incident in terrorist life-threatening response situations are presented. MATERIAL AND METHODS: The Inter-Hospital Security Conference Baden-Württemberg (IHSC BW) is an association of representatives of acute hospitals in Baden-Württemberg, the Ministry of the Interior, Digitalization and Migration Baden-Württemberg, the Ministry of Social Affairs and Integration Baden-Württemberg, the State Police Headquarters Baden-Württemberg and the Baden-Württemberg Hospital Association. From 2018 to 2020, the IHSC BW developed recommendations for action on cooperation between police, hospitals and non-police emergency response. The recommendations for action were agreed by the group members in 6 working sessions and initialled in two subsequent video conferences. A recommendation was considered adopted when the IHSC BW plenary assembly finally gave its approval with an absolute majority. RESULTS AND DISCUSSION: Competence-based interface solutions for a smooth cooperation between prehospital and hospital management in the care of patients who have become victims of a terrorist attack are to be demanded. For preliminary planning, the establishment of a local safety conference at the county disaster control authority level with the following participants is recommended: disaster control authority, fire department, regional police headquarters, chief emergency physician, rescue services and disaster control officers of affected clinics. It is recommended to set up a joint command and situation center (CSC), where management personnel from the police, rescue service, fire department and disaster control can meet to organize the handling of the incident jointly, competently and without loss of time. From this CSC, a liaison officer should then provide the clinics with information at regular intervals. Exercises should take place regularly. Cross-organizational exercises are particularly important, and this is one of the tasks of the local safety conference.

[Resilience against IT attacks in hospitals : Results from an exercise in a German university hospital]. / Resilienz gegen IT-Angriffe an Kliniken : Ergebnisse einer Stabsrahmenübung an einem Universitätsklinikum.

BACKGROUND: According to the legal definition healthcare systems and their components (e.g., hospitals) are part of the critical infrastructure of modern industrial nations. During the last few years hospitals increasingly became targets of cyber attacks causing severe impairment of their operability for weeks or even months. According to the German federal strategy for protection of critical infrastructures (KRITIS strategy), hospitals are obligated to take precautions against potential cyber attacks or other IT incidents. OBJECTIVE: This article describes the process of planning, execution and results of an advanced table-top exercise which took place in a university hospital in Germany and simulated the first 3 days after a cyber attack causing a total failure of highly critical IT systems. MATERIAL AND METHODS: During a first stage lasting about 8 months IT-dependent processes within the clinical routine were identified and analyzed. Then paper-based and off-line back-up processes and workarounds were developed and department-specific emergency plans were defined. Finally, selected central facilities such as pharmacy, laboratory, radiology, IT and the hospitals crisis management team took part in the actual disaster exercise. Afterwards the participants were asked to evaluate the exercise and the hospitals cyber security using a questionnaire. On this basis the authors visualized the hospital's resilience against cyber incidents and defined short-term, medium-term and long-term needs for action. RESULTS: Of the participants 85% assessed the exercise as beneficial, 97% indicated that they received adequate support during the preparations and 75% had received sufficient information; however, only 34% had the opinion that the hospital's and their own preparedness against critical IT failures were sufficient. Before the exercise took place, IT-specific emergency plans were present only in 1.7% of the hospital facilities but after the exercise in 86.7% of the clinical and technical departments. The highest resilience against cyber attacks was not surprisingly reported by facilities that still work routinely with paper-based or off-line processes, the IT department showed the lowest resilience as it would come to a complete shutdown in cases of a total IT failure. CONCLUSION: The authors concluded that the planning phase is the most important stage of developing the whole exercise, giving the best opportunity for working out fallback levels and workarounds and through this strengthen the hospitals resilience against cyber attacks and comparable incidents. A meticulous preparedness can minimize the severe effects a total IT failure can cause on patient care, staff and the hospital as a whole.

Early changes of intracranial pressure, perfusion pressure, and blood flow after acute head injury. Part 1: An experimental study of the underlying pathophysiology.

The present study examines intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cerebral circulation immediately after experimental head injury in an animal model. The underlying systemic hemodynamic changes were also observed. To produce a standardized head injury, a fluid-percussion device was applied to the dura at the midline of 10 piglets. Seven other nontraumatized animals served as a control group. Hemodynamic parameters as well as ICP and CPP were recorded on-line, one value every 1.4 seconds. Cerebral blood flow (CBF) and cerebral vascular resistance (CVR) were measured three times using a microsphere technique. Immediately after head injury, the traumatized animals showed a sudden increase in ICP, with a maximum of 40 torr at 3 to 5 minutes, while there was a pronounced decrease in CPP from 85 to 40 torr. The CBF in the various brain areas fell from 55 to 22 ml/min/100 gm within 5 minutes after the impact, and CVR increased to 300% of control values within 90 minutes. The findings of this study demonstrated that cerebral circulation is critically jeopardized within a few minutes after trauma. This, in combination with a subsequent increase in CVR, makes the early development of ischemic brain damage very likely. In traumatized patients, treatment prior to hospital admission must therefore be directed at prevention of this fatal course.

Spectral analysis of ventricular fibrillation and closed-chest cardiopulmonary resuscitation.

This study was designed to assess the interference by closed-chest cardiopulmonary resuscitation (CPR) on the ventricular fibrillation (VF) ECG signal in a porcine model of cardiac arrest and to elucidate which variable of VF spectral analysis reflects best myocardial blood flow and resuscitation success during CPR. Fourteen domestic pigs were allocated to receive either 0.4 U/kg vasopressin (n = 7) or 10 ml saline (n = 7) after 4 min of VF and 3 min of CPR. Using radiolabeled microspheres, myocardial blood flow was determined during CPR before, and 90 s and 5 min after, drug administration. Using spectral analysis of VF, the median frequency, dominant frequency, edge frequency and amplitude of VF were determined simultaneously and before the first defibrillation attempt. Using filters in order to specify frequency ranges, stepwise elimination of mechanical artifacts resulting from CPR revealed that at a frequency bandpass of 4.3-35 Hz, median fibrillation frequency has a sensitivity, specificity, positive and negative predictive value of 100% to differentiate between resuscitated and non-resuscitated animals. The best correlation between myocardial blood flow and fibrillation frequency was found at a median frequency range of 4.3-35 Hz. We conclude that spectral analysis of VF can provide reliable information relating to successful resuscitation. In this model after elimination of oscillations due to mechanical CPR, median fibrillation frequency best reflects the probability of resuscitation success.

Effects of epinephrine and vasopressin on median fibrillation frequency and defibrillation success in a porcine model of cardiopulmonary resuscitation.

OBJECTIVE: This study was designed to assess whether median frequency of ventricular fibrillation (VF) correlates with myocardial blood flow and defibrillation success during cardiopulmonary resuscitation (CPR) after epinephrine or vasopressin administration. METHODS AND RESULTS: After 4 min of VF and 3 min of CPR, 14 pigs received 0.045 mg/kg epinephrine or 0.4 U/kg vasopressin. Using radio-labeled microspheres, median myocardial blood flow during CPR before, and 90 s and 5 min after drug administration (DA) was 15.5 (12.6, 23.1; 25th percentile, 75th percentile), 26.4 (18.5, 29.1), 16.9 (14.9, 19.1) mL min-1 100 g-1, respectively, in the epinephrine, and 16.9 (15.4, 18.9), 48.1 (36.9, 68.9) (P < 0.05 vs. before DA), 52.3 (38.5, 65.0) mL min-1 100 g-1, respectively, in the vasopressin group. Using spectral analysis of VF, median frequency of VF was 11.0 (10.7, 11.8), 11.3 (9.6, 13.1), 10.2, (8.8, 11.4) Hz, respectively, in the epinephrine, and 10.1 (10.0, 10.5), 11.7 (11.1, 14.2) (P < 0.05 vs. before DA), 13.2 (11.5, 13.9) Hz, respectively, in the vasopressin group at the same points in time. Median frequency correlates significantly with myocardial blood flow in the epinephrine (n = 21); rs = 0.772; P < 0.001) and in the vasopressin group (n = 21; rs = 0.905; P < 0.001). Median fibrillation frequency before the first defibrillation was 13.0 (12.2, 13.2) Hz in resuscitated (n = 8) and 9.2 (8.3, 10.2) Hz (n = 6) in non-resuscitated animals (P < 0.01). CONCLUSIONS: We conclude that median frequency of VF reflects myocardial blood flow and the chance of successful defibrillation during closed-chest CPR after vasopressor treatment in a porcine model of VF.

Arterial blood gases in patients with acute head injury at the accident site and upon hospital admission.

Prior to the start of supportive therapy at the site of the accident, arterial blood samples from 47 patients with acute head injury were taken for blood gas analysis. At the same time, the degree of unconsciousness was assessed using the Glasgow-Coma-Scale. After transport to the hospital, arterial blood gases and the level of unconsciousness were again determined. A very close correlation was found between the initial depth of unconsciousness and the degree of hypercapnia (R = -0.90). Patients with head injury and other multiple injuries did not differ in this report (R = -0.95) from those with isolated head injury. The correlation between PaO2 and the degree of unconsciousness was less well defined, and the results showed a greater degree of scatter (R = 0.54). The acidosis observed resulted mainly from the rise in PaCO2. The absence of any correlation between the base excess and the Glasgow-Coma-Scale levels (R = -0.27) makes a common metabolic derangement unlikely. As a result of intubation and controlled ventilation, the hypercapnia of the comatose patients had been corrected, and a correlation could no longer be found between the Glasgow-Coma-Scale level and the PaCO2. In order to avoid hypoventilation, which carries with it the danger of a rise in intracranial pressure, all patients with severe head injury should be intubated and ventilated as soon as possible after the accident.

Effects of epinephrine and norepinephrine on cerebral oxygen delivery and consumption during open-chest CPR.

The effect of epinephrine and norepinephrine on cerebral oxygen delivery and consumption after five minutes of cardiopulmonary arrest and three minutes of open-chest cardiac massage was studied in 21 pigs. Norepinephrine, like epinephrine, has a marked alpha- and beta 1-sympathomimetic activity, but compared with epinephrine, the degree of beta 2-stimulation is weak. Epinephrine probably stimulates cerebral oxygen and glucose consumption by its beta 2-adrenergic effect. After three minutes of CPR, three groups of seven animals each blindly received either placebo (control group), 45 micrograms/kg epinephrine, or 45 micrograms/kg norepinephrine. During CPR but before drug administration, cerebral blood flow was 23 +/- 14 mL/min/100 g in the control group, 30 +/- 7 mL/min/100 g in the epinephrine group, and 30 +/- 11 mL/min/100 g in the norepinephrine group. At 90 seconds after epinephrine, cerebral blood flow increased to 54 +/- 14 mL/min/100 g and after norepinephrine, to 58 +/- 22 mL/min/100 g (P less than .05). Cerebral perfusion pressure for both drugs was significantly higher than the control group. Compared with mechanical measures alone, cerebral oxygen delivery rose from 4.3 +/- 1.2 to 7.4 +/- 1.7 mL/min/100 g after epinephrine and from 3.7 +/- 1.4 to 7.3 +/- 2.7 mL/min/100 g after norepinephrine (P less than .05). There was no increase in cerebral oxygen consumption after both catecholamines, and cerebral oxygen extraction ratio decreased. Cerebral glucose delivery increased in relation to glucose consumption, and extraction ratio did not change significantly after both catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II augments reflex activity of the sympathetic nervous system during cardiopulmonary resuscitation in pigs.

BACKGROUND: During hypotensive states, angiotensin II augments reflex activity of the sympathetic nervous system. The purpose of the present study was to assess the effects of this vasoconstrictor on myocardial blood flow and plasma catecholamine concentrations during and after CPR. METHODS AND RESULTS: After 4 minutes of ventricular fibrillation and 3 minutes of open-chest CPR, 14 pigs (24 to 26 kg) were randomized into two groups receiving either saline (n = 7) or 0.05 mg/kg angiotensin II (n = 7). Arterial plasma catecholamine concentration was measured with high-pressure liquid chromatography. Organ blood flow was measured with radiolabeled microspheres. During CPR, after drug administration, left ventricular myocardial blood flow was significantly higher in the angiotensin II-treated group than in the control group. During CPR, median epinephrine concentrations before and 90 seconds and 5 minutes after drug administration were 63.0, 35.2, and 22.5 ng/mL, respectively, in the control group and 63.2, 139.8, and 154.2 ng/mL, respectively, in the angiotensin II group (P < .001 at 90 seconds and P < .01 at 5 minutes). At the same times, median norepinephrine concentrations were 52.6, 59.8, and 33.9 ng/mL, respectively, in the control group and 42.5, 98.7, and 111.3 ng/mL, respectively, in the angiotensin II group (P < .01 at 5 minutes). Restoration of spontaneous circulation was possible in all of the angiotensin II-treated pigs, whereas only 3 of the 7 saline-treated pigs could be resuscitated. At 5 minutes after successful resuscitation, epinephrine was 6.8 ng/mL in the control group and 16.1 ng/mL in the angiotensin II group (P < .05). CONCLUSIONS: During CPR, angiotensin II appears to increase coronary perfusion pressure and myocardial blood flow, not only by direct peripheral arteriolar vasoconstriction via angiotensin II receptors but also by inducing a massive catecholamine release with adrenergic peripheral vasoconstriction.

Effects of ventilation on hemodynamics and myocardial blood flow during active compression-decompression resuscitation in pigs.

BACKGROUND: Active compression-decompression (ACD) improves hemodynamics and vital organ blood flow during cardiopulmonary resuscitation. The effects of intermittent positive pressure ventilation (IPPV) on ACD have not been studied. This study was designed to compare the effects of ACD with and without IPPV on gas exchange, hemodynamics, and myocardial blood flow. METHODS: After 30 s ventricular fibrillation, 14 tracheally intubated pigs were allocated to receive either ACD combined with IPPV (ACD-IPPV) or ACD alone. In animals treated with ACD-IPPV, the lungs were ventilated using a servo ventilator. Animals treated with ACD received 100% oxygen by a reservoir but ventilation was not assisted. RESULTS: Minute ventilation (median) was 6.5 and 6.1 l/min after 1 and 7 min of ACD-IPPV, and was 4.2 and 1.6 l/min after 1 and 7 min of ACD. In contrast to ACD-IPPV, PaO2 was less and PaCO2 was greater with ACD. Mean arterial (53 and 40 mmHg; P < 0.05) and mean central venous pressure (25 and 14 mmHg; P < 0.01) were greater during ACD-IPPV as compared with ACD. After administration of epinephrine 0.2 mg/kg, myocardial blood flow increased only in ACD-IPPV treated animals, and 5 min after epinephrine administration, myocardial blood flow was greater during ACD-IPPV (33 ml.min-1.100 g-1) as compared with ACD (15 ml.min-1.100 g-1; P < 0.05). Restoration of spontaneous circulation could be achieved only in animals subjected to ACD-IPPV. CONCLUSIONS: Gas exchange was critically impaired during the late phase of ACD. Compared with ACD-IPPV, myocardial blood flow was less preserved with ACD and was too low to achieve restoration of spontaneous circulation.

Effect of angiotensin II on myocardial blood flow and acid-base status in a pig model of cardiopulmonary resuscitation.

The effect of angiotensin II on myocardial blood flow and acid-base status during cardiopulmonary resuscitation (CPR) was assessed. Fourteen pigs were allocated randomly to receive either 0.9% saline (n = 7) or 0.05 mg/kg angiotensin II (n = 7) after 4 min of ventricular fibrillation and 3 min of open-chest CPR. Total myocardial blood flow (measured with radiolabeled microspheres) before, 90 s, and 5 min following drug administration was 74 +/- 18, 62 +/- 12, and 54 +/- 11 mL.min-1 x 100g-1 (mean +/- SD) in the control, and 72 +/- 17, 125 +/- 25, and 74 +/- 20 mL.min-1 x 100 g-1 in the angiotensin II group (P < 0.001 at 90 s and P < 0.05 at 5 min). The PCO2 of coronary venous blood at 90 s after drug administration was 82 +/- 8 mm Hg in the control group as compared to 47 +/- 9 mm Hg in the angiotensin II group (P < 0.001). Only three of the seven control group animals could be resuscitated successfully, whereas all of the angiotensin II-treated pigs survived the 1-h observation period (P < 0.05), during which neither arterial hypertension nor bradycardia was observed. Angiotensin II was associated with an improvement of myocardial blood flow during CPR and short-term resuscitation success. The increase in myocardial perfusion is associated with a lower coronary venous PCO2 and a higher coronary venous pH. The authors conclude that angiotensin II administration facilitated cardiopulmonary resuscitation.

Effects of active compression-decompression resuscitation on myocardial and cerebral blood flow in pigs.

BACKGROUND: This study was designed to assess the effects of a modified cardiopulmonary resuscitation (CPR) technique that consists of both active compression and active decompression of the chest (ACD CPR) versus standard CPR (STD CPR) on myocardial and cerebral blood flow during ventricular fibrillation both before and after epinephrine administration. METHODS AND RESULTS: During a 30-second period of ventricular fibrillation cardiac arrest, 14 pigs were randomized to receive either STD CPR (n = 7) or ACD CPR (n = 7). Both STD and ACD CPR were performed using an automated pneumatic piston device applied midsternum, designed to provide either active chest compression (1.5 to 2.0 in.) and decompression or only active compression of the chest at 80 compressions per minute and 50% duty cycle. Using radiolabeled microspheres, median total myocardial blood flow after 5 minutes of ventricular fibrillation was 14 (7 to 30, minimum to maximum) STD CPR versus 30 (9 to 46) mL.min-1 x 100 g-1 with ACD CPR (P < .05). Median cerebral blood flow was 15 (10 to 26) mL.min-1 x 100 g-1 with STD CPR and 30 (21 to 39) with ACD CPR (P < .01). When comparing STD with ACD CPR, aortic systolic (62 mm Hg [48 to 70] vs 80 [59 to 86]) and diastolic (22 [18 to 28] vs 28 [21 to 36]) pressures, calculated coronary systolic (30 [22 to 36] vs 49 [37 to 56]) and diastolic (18 [16 to 23] vs 26 [21 to 31]) perfusion pressures, end-tidal CO2 (1.4% [0.8 to 1.8] vs 2.1 (1.8 to 2.4]), cerebral O2 delivery (3.1 mL.min-1 x 100 g-1 [1.5 to 4.5] vs 5.3 [3.8 to 7.5]), and cerebral perfusion pressure (14 mm Hg [4 to 22] vs 26 [6 to 34]) were all significantly higher with ACD CPR: To compare these parameters before and after vasopressor therapy, a bolus of high-dose epinephrine (0.2 mg/kg) was given to all animals after 5 minutes of ventricular fibrillation. Organ blood flow and calculated perfusion pressures increased significantly in both the STD and ACD groups after epinephrine. The differences observed between STD and ACD CPR before epinephrine were diminished 90 seconds after epinephrine but were again statistically significant when assessed 5 minutes later, once the acute effects of epinephrine had decreased. No difference in short-term resuscitation success was found between the two groups. CONCLUSIONS: We conclude that ACD CPR significantly increases myocardial and cerebral blood flow during cardiac arrest in the absence of vasopressor therapy compared with STD CPR:

Effect of vasopressin on hemodynamic variables, organ blood flow, and acid-base status in a pig model of cardiopulmonary resuscitation.

Based upon the hypothesis that vasopressin (antidiuretic hormone) may increase vascular resistance during ventricular fibrillation, the effects of this potent vasoconstrictor were studied in a porcine model of ventricular fibrillation. Vasopressin therapy was compared to epinephrine by randomly allocating 14 pigs to receive either 0.045 mg/kg of epinephrine (n = 7) or 0.8 U/kg of vasopressin (n = 7) after 4 min of ventricular fibrillation and 3 min of open-chest cardiopulmonary resuscitation. During cardiopulmonary resuscitation, myocardial blood flow before and 90 s and 5 min after drug administration was 57 +/- 11, 84 +/- 11, and 59 +/- 9 mL.min-1 x 100 g-1 (mean +/- SEM) in the epinephrine group, and 61 +/- 5, 148 +/- 26, and 122 +/- 22 mL.min-1 x 100 g-1 in the vasopressin group (P < 0.05 at 90 s and 5 min). At the same times, mean cardiac index was not significantly different between the groups. After drug administration, coronary venous PCO2 was significantly higher and coronary venous pH was significantly lower in the epinephrine as compared to the vasopressin group. All pigs in both groups were resuscitated and survived the 2-h observation period. We conclude that vasopressin improves vital organ perfusion during ventricular fibrillation and cardiopulmonary resuscitation. Vasopressin seems to be at least as effective as epinephrine in this pig model of ventricular fibrillation.

Vasopressin improves vital organ blood flow during closed-chest cardiopulmonary resuscitation in pigs.

BACKGROUND: This study was designed to compare the effects of epinephrine with those of vasopressin on vital organ blood flow during closed-chest cardiopulmonary resuscitation (CPR) in a pig model of ventricular fibrillation. METHODS AND RESULTS: Vasopressin was compared with epinephrine by randomly allocating 28 pigs to receive either 0.2 mg/kg epinephrine (n = 7), 0.2 U/kg vasopressin (low dose) (n = 7), 0.4 U/kg vasopressin (medium dose) (n = 7), or 0.8 U/kg vasopressin (high dose) (n = 7) after 4 minutes of ventricular fibrillation and 3 minutes of closed-chest CPR. Left ventricular myocardial blood flow, determined by use of radiolabeled microspheres during CPR, before and then 90 seconds and 5 minutes after drug administration was 17 +/- 2, 43 +/- 5, and 22 +/- 3 mL.min-1.100 g-1 (mean +/- SEM) in the epinephrine group; 18 +/- 2, 50 +/- 6, and 29 +/- 3 mL.min-1.100 g-1 in the low-dose vasopressin group; 17 +/- 3, 52 +/- 8, and 52 +/- 6 mL.min-1.100 g-1 in the medium-dose vasopressin group; and 18 +/- 2, 95 +/- 9, and 57 +/- 6 mL.min-1.100 g-1 in the high-dose vasopressin group (P < .001 at 90 seconds and 5 minutes between epinephrine and high-dose vasopressin, and P < .01 at 5 minutes between epinephrine and medium-dose vasopressin). At the same times, calculated coronary systolic perfusion pressures were 12 +/- 2, 36 +/- 5, and 18 +/- 2 mm Hg in the epinephrine group; 10 +/- 1, 39 +/- 6, and 26 +/- 5 mm Hg in the low-dose vasopressin group; 11 +/- 2, 49 +/- 6, and 38 +/- 5 mm Hg in the medium-dose vasopressin group; and 10 +/- 2, 70 +/- 5, and 47 +/- 6 mm Hg in the high-dose vasopressin group (P < .01 at 90 seconds and 5 minutes between epinephrine and high-dose vasopressin); and calculated coronary diastolic perfusion pressures were 15 +/- 2, 24 +/- 2, and 19 +/- 2 mm Hg in the epinephrine group; 13 +/- 1, 25 +/- 2, and 20 +/- 1 mm Hg in the low-dose vasopressin group; 13 +/- 2, 25 +/- 2, and 21 +/- 2 mm Hg in the medium-dose vasopressin group; and 13 +/- 2, 35 +/- 3, and 24 +/- 2 mm Hg in the high-dose vasopressin group (P < .05 at 90 seconds between epinephrine and high-dose vasopressin). Total cerebral blood flow was significantly higher after high-dose vasopressin than after epinephrine (P < .05 at 90 seconds and P < .01 at 5 minutes between groups). Five animals in the epinephrine, 5 in the low-dose vasopressin, 7 in the medium-dose vasopressin, and 6 in the high-dose vasopressin groups were successfully resuscitated and survived the 1-hour observation period. CONCLUSIONS: We conclude that administration of vasopressin leads to a significantly higher coronary perfusion pressure and myocardial blood flow than epinephrine during closed-chest CPR in a pig model of ventricular fibrillation.