Point-of-care analysis of intraosseous samples

Background Clinical decisions in prehospital critical care are often based on limited information about the patient’s medical history and the events preceding the acute illness. In addition to physical examination, point-of-care (POC) laboratory diagnostics can provide information for decision-making. Unfortunately, obtaining blood samples for POC analysis from critically ill patients can sometimes be difficult, thus diminishing the usefulness of POC analyses in prehospital critical care. Intraosseous (IO) access is used as an optional vascular route for fluid and medication administration for emergency patients when difficulties with venous access are encountered. Using IO access as a source of POC laboratory samples is interesting; however, evidence regarding the feasibility and agreement of these samples with arterial and venous samples is scarce. We therefore designed a series of studies to obtain more information on the POC analysis of IO samples. Materials and methods First, we performed a systematic literature review of the studies addressing the POC analyses of IO samples (Study I). We included all publications using POC or conventional laboratory methods to compare IO samples with venous or arterial samples for the parameters relevant to emergency care. Second, we performed an observational study within 31 healthy volunteers (Study II). We evaluated the feasibility of IO analyses with an i-STAT® POC device and the agreement of IO values with arterial and venous values. The agreement was evaluated using the Bland–Altman method. In addition, we examined the necessity to draw waste blood before taking the actual IO sample for POC analysis. Third, we studied the usability of IO POC values under unstable haemodynamic conditions with an experimental porcine (n = 23) resuscitation model (Study III). The model simulated a real-life course of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). Four repeated samples were simultaneously drawn from the IO access, artery and central vein during CA and CPR, and were instantly analysed with an i-STAT® POC device. The laboratory values were plotted as a function of time to demonstrate their development during CA and CPR. The arterial, venous and IO samples which were taken during CPR were compared with the arterial baseline samples to observe how they resemble the pre-arrest state. Last, in an observational study, we analysed the agreement between IO and arterial samples obtained from 35 critically ill prehospital patients, using the Bland–Altman method (Study IV). Moreover, we administered a questionnaire about acceptable biases in clinical practice to 16 experienced emergency physicians and compared our results with their responses. Results The 27 reviewed studies had heterogeneous populations: healthy volunteers, haemodynamically stable and unstable animals, adult and paediatric haematologic patients, and emergency patients. Only three of these studies followed the recommended guidelines for method comparison studies. The sample sizes were relatively small (n = 14–20) and the populations were heterogeneous in these three studies precluding the combining of results for meta-analysis. However, in IO samples, potassium values were generally higher than in arterial or venous samples. In the observational studies, we found that the POC analyses of IO samples were often feasible. Higher failure rates were associated with higher age. Agreement of IO values with arterial values appeared acceptable for base excess, pH, standard bicarbonate, lactate, glucose, ionised calcium and sodium within healthy volunteers and critically ill emergency patients. Potassium values from IO samples were systematically higher than arterial and venous values (biases 1.8–2.2 mmol/l). Agreement within haemoglobin and haematocrit measurements showed very large variety (95% limits of agreement in the bias of haemoglobin up to 95 g/l). However, the sample sizes were too small to unequivocally prove the agreement. Using the resuscitation model, we discovered that IO, arterial and venous values changed differently from one another during CA and CPR. Acidaemia was detectable in IO samples during untreated ventricular fibrillation, but in arterial samples the acidaemia was evident only after the initiation of CPR. The average potassium values during CPR from IO, arterial and venous samples were 4.4, 3.3, and 2.8 mmol/l higher than the pre-arrest arterial values, respectively. Conclusions When obtaining vascular access is challenging, IO access can be used for emergency POC analyses; however, the results of IO POC analyses should be interpreted with care. Waste blood does not need to be taken before the sample. POC analyses of IO samples may fail for older patients. In general, potassium values from IO samples are usually higher than those from arterial and venous samples, haemoglobin and haematocrit measurements from IO access are not reliable, and partial pressure measurements of oxygen and carbon dioxide from IO samples represent venous rather than arterial values.Päätöksenteko ensihoidossa perustuu usein niukkaan tietoon potilaan sairauksista ja tapahtumista ennen akuuttia ongelmaa. Potilaan tutkimisen lisäksi verinäytteiden vierianalyysin avulla voidaan saada hyödyllistä tietoa päätöksenteon tueksi. Verinäytteiden saaminen kriittisesti sairaalta potilaalta voi kuitenkin olla vaikeaa vähentäen vierianalytiikan mahdollisuuksia ensihoidossa. Luuydinyhteyttä käytetään yleisesti vaihtoehtona neste- ja lääkehoidon toteuttamiseen hätätilapotilailla, mikäli laskimoyhteys ei onnistu. Luuydinyhteyden käyttö vierianalyysiin vaikuttaa kiinnostavalta, mutta sen onnistumisesta ja näytteiden yhtäpitävyydestä verinäytteisiin on hyvin vähän tutkimustietoa. Väitöskirjatutkimus koostuu systemaattisesta kirjallisuuskatsauksesta sekä kolmesta havainnoivasta työstä. Ensimmäisessä työssä tutkitaan luuydinyhteyden käytettävyyttä vierianalyysiin 31 terveellä vapaaehtoisella koehenkilöllä. Toisessa työssä arvioidaan koe-eläinmallin (n=23) avulla epävakaan verenkierron, sydänpysähdyksen sekä elvytyksen vaikutuksia luuydinnäytteiden ja verinäytteiden yhtäpitävyyteen. Kolmannessa työssä tutkitaan luuydinnäytteiden ja valtimoverinäytteiden yhtäpitävyyttä 35:llä kriittisesti sairaalla ensihoitopotilaalla. Yhtäpitävyyden arviointiin käytetään Bland–Altman menetelmää. Systemaattiseen kirjallisuuskatsaukseen valikoituneiden 27 julkaisun aineistot olivat hyvin heterogeenisia ja vain kolme tutkimusta noudatti menetelmävertailututkimuksille suositeltuja tilastollisia menetelmiä. Näiden kolmen tutkimuksen aineistot olivat niin pieniä ja heterogeenisiä, että tuloksista ei voida tehdä johtopäätöksiä koskien kriittisesti sairaita ensihoitopotilaita. Havainnoivien tutkimusten perusteella voidaan todeta, että luuydinnäytteiden vierianalyysi on usein mahdollista, joskin vanhemmilla potilailla epäonnistumisen todennäköisyys on suurempi. Luuydinnäytteiden yhtäpitävyys vaikuttaa hyväksyttävältä emäsylimäärän, pH:n, bikarbonaatin, laktaatin, glukoosin, ionisoidun kalsiumin ja natriumin osalta. Kalium-määritys luuydinnäytteestä osoittaa systemaattisesti korkeampia arvoja verrattuna valtimo- ja laskimoverinäytteisiin. Hemoglobiinimääritys luuydinnäytteistä ei ole luotettava. Sydänpysähdyksen ja elvytyksen aikana laboratorioarvot luuytimestä, laskimoverestä ja valtimoverestä muuttuvat eri tahtiin. Väitöskirjatutkimuksen johtopäätöksenä voidaan todeta, että mikäli verinäytteen saaminen kriittisesti sairaalta potilaalta on ongelmallista, luuydinyhteydestä voidaan ottaa vierianalyysinäytteitä, joskin niiden tuloksia pitää tulkita kriittisesti ja menetelmän rajoitukset ymmärtäen

Voiko luuydinyhteyden kautta ottaa vierinäytteitä?

Väittelijä Milla Jousi ; Helsingin yliopist

Intraosseous blood samples for point-of-care analysis : agreement between intraosseous and arterial analyses

Background: Point-of-care (POC) testing is highly useful when treating critically ill patients. In case of difficult vascular access, the intraosseous (IO) route is commonly used, and blood is aspirated to confirm the correct position of the IO-needle. Thus, IO blood samples could be easily accessed for POC analyses in emergency situations. The aim of this study was to determine whether IO values agree sufficiently with arterial values to be used for clinical decision making. Methods: Two samples of IO blood were drawn from 31 healthy volunteers and compared with arterial samples. The samples were analysed for sodium, potassium, ionized calcium, glucose, haemoglobin, haematocrit, pH, blood gases, base excess, bicarbonate, and lactate using the i-STAT (R) POC device. Agreement and reliability were estimated by using the Bland-Altman method and intraclass correlation coefficient calculations. Results: Good agreement was evident between the IO and arterial samples for pH, glucose, and lactate. Potassium levels were clearly higher in the IO samples than those from arterial blood. Base excess and bicarbonate were slightly higher, and sodium and ionised calcium values were slightly lower, in the IO samples compared with the arterial values. The blood gases in the IO samples were between arterial and venous values. Haemoglobin and haematocrit showed remarkable variation in agreement. Discussion: POC diagnostics of IO blood can be a useful tool to guide treatment in critical emergency care. Seeking out the reversible causes of cardiac arrest or assessing the severity of shock are examples of situations in which obtaining vascular access and blood samples can be difficult, though information about the electrolytes, acid-base balance, and lactate could guide clinical decision making. The analysis of IO samples should though be limited to situations in which no other option is available, and the results should be interpreted with caution, because there is not yet enough scientific evidence regarding the agreement of IO and arterial results among unstable patients. Conclusions: IO blood samples are suitable for analysis with the i-STAT (R) point-of-care device in emergency care. The aspirate used to confirm the correct placement of the IO needle can also be used for analysis. The results must be interpreted within a clinical context while taking the magnitude and direction of bias into account.Peer reviewe

Pre-hospital suPAR, lactate and CRP measurements for decision-making : a prospective, observational study of patients presenting non-specific complaints

Publisher Copyright: © 2021, The Author(s).Background: In the pre-hospital setting, non-urgent patients with non-specific chief complaints pose assessment challenges for the emergency medical systems (EMS). Severely ill patients should be identified among these patients, and unnecessary transport to the emergency department (ED) should be avoided. Unnecessary admissions burden EDs, deplete EMS resources and can even be harmful to patients, especially elderly patients. Therefore, tools for facilitating pre-hospital decision-making are needed. They could be based on vital signs or point-of-care laboratory biomarkers. In this study, we examined whether the biomarker soluble urokinase plasminogen activator receptor (suPAR), either alone or combined with C-reactive protein (CRP) and/or lactate, could predict discharge from the ED and act as a pre-hospital support tool for non-conveyance decision-making. Methods: This was a prospective, observational study of adult patients with normal or near-normal vital signs transported by an EMS to an ED with a code referring to deteriorated general condition. The levels of suPAR, CRP and lactate in the patients’ pre-hospital blood samples were analysed. The values of hospitalized patients were compared to those of discharged patients to determine whether these biomarkers could predict direct discharge from the ED. Results: A total of 109 patients (median age: 81 years) were included in the study. Of those, 52% were hospitalized and 48% were discharged from the ED. No statistically significant association was found between suPAR and the ED discharge vs hospitalization outcome (OR: 1.04, 95% CI 0.97–1.13, AUROC: 0.58, 95% CI 0.47–0.69). Adding CRP (AUROC: 0.64, 95% CI 0.54–0.75) or lactate (AUROC: 0.60, 95% CI 0.49–0.71) to the regression models did not improve their diagnostic accuracy. None of the patients with a suPAR value of less than 2 ng/ml were admitted to hospital, while 64% of the patients with a suPAR value of more than 6 ng/ml were hospitalized. Conclusion: Pre-hospital suPAR measurements alone or combined with CRP and/or lactate measurements could not predict the ED discharge or hospital admission of 109 non-urgent EMS patients with non-specific chief complaints and normal or near-normal vital signs.Peer reviewe

The effect of 50% compared to 100% inspired oxygen fraction on brain oxygenation and post cardiac arrest mitochondrial function in experimental cardiac arrest

Background and aim: We hypothesised that the use of 50% compared to 100% oxygen maintains cerebral oxygenation and ameliorates the disturbance of cardiac mitochondrial respiration during cardiopulmonary resuscitation (CPR). Methods: Ventricular fibrillation (VF) was induced electrically in anaesthetised healthy adult pigs and left untreated for seven minutes followed by randomisation to manual ventilation with 50% or 100% oxygen and mechanical chest compressions (LUCAS (R)). Defibrillation was performed at thirteen minutes and repeated if necessary every two minutes with 1 mg intravenous adrenaline. Cerebral oxygenation was measured with near-infrared spectroscopy (rSO(2), INVOS (TM) 5100C Cerebral Oximeter) and with a probe (NEUROVENT-PTO, RAUMEDIC) in the frontal brain cortex (PbO2). Heart biopsies were obtained 20 min after the return of spontaneous circulation (ROSC) with an analysis of mitochondrial respiration (OROBOROS Instruments Corp., Innsbruck, Austria), and compared to four control animals without VF and CPR. Brain rSO(2) and PbO2 were log transformed and analysed with a mixed linear model and mitochondrial respiration with an analysis of variance. Results: Of the twenty pigs, one had a breach of protocol and was excluded, leaving nine pigs in the 50% group and ten in the 100% group. Return of spontaneous circulation (ROSC) was achieved in six pigs in the 50% group and eight in the 100% group. The rSO(2) (p = 0.007) was lower with FiO(2) 50%, but the PbO2 was not (p = 0.93). After ROSC there were significant interactions between time and FiO(2) regarding both rSO(2) (p = 0.001) and PbO2 (p = 0.004). Compared to the controls, mitochondrial respiration was decreased, with adenosine diphosphate (ADP) levels of 57 (17) pmol s(-1) mg(-1) compared to 92 (23) pmol s(-1) mg(-1) (p = 0.008), but there was no difference between different oxygen fractions (p = 0.79). Conclusions: The use of 50% oxygen during CPR results in lower cerebral oximetry values compared to 100% oxygen but there is no difference in brain tissue oxygen. Cardiac arrest disturbs cardiac mitochondrial respiration, but it is not alleviated with the use of 50% compared to 100% oxygen (Ethical and hospital approvals ESAVI/1077/04.10.07/2016 and HUS/215/2016, 7 30.3.2016, Funding Helsinki University and others). (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

The role of pre-hospital blood gas analysis in trauma resuscitation

Peer reviewe

44 Point-of-care analysis of lactate from intraosseous samples during resuscitation

Aim Intraosseous (IO) access with power-driven devices has become a commonly used method of vascular access during cardiopulmonary resuscitation (CPR). Blood aspirated to confirm correct IO needle position could readily be available for point-of-care (POC) testing. The aim was to investigate how POC lactate levels of intraosseous blood reflect the lactate values in systemic circulation during VF and resuscitation in order to see whether POC IO samples could be used for clinical decision-making during CPR. Methods We conducted an experimental study comparing POC results of lactate from intraosseous, arterial and venous blood of 23 piglets undergoing induced cardiac arrest (VF) and CPR. All blood samples were analysed with i-STAT POC device and the results were compared using Bland-Altman method (ref 1). Results Prior to VF the IO lactate levels were similar to arterial and venous samples (bias [95% CI] between IO and arterial samples was 0.11 mmol/L [−0.02–0.24] and between IO and venous samples 0.03 mmol/L [−0.25–0.31]). Five minutes after onset of VF, intraosseous lactate levels had increased more than arterial and venous values (bias 3.76 mmol/L [1.93–5.59] and 3.52 mmol/L [1.41–5.64] respectively). Five minutes after initiation of CPR with an automatic CPR device (LucasTM) the difference diminished (bias 0.81 mmol/L, [−0.31–1.93] and 1.50 mmol/L [0.07–2.92]). Conclusion Intraosseous lactate values showed good agreement with arterial and venous values before cardiac arrest, but IO values were clearly higher during VF and CPR. During resuscitation IO lactate values seem to represent better the metabolic state at tissue level than arterial or venous lactate. Reference Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet1986;1:307–10 Conflict of interest None declared. Funding None declared

EuReCa ONE—27 Nations, ONE Europe, ONE Registry A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe

AbstractIntroductionThe aim of the EuReCa ONE study was to determine the incidence, process, and outcome for out of hospital cardiac arrest (OHCA) throughout Europe.MethodsThis was an international, prospective, multi-centre one-month study. Patients who suffered an OHCA during October 2014 who were attended and/or treated by an Emergency Medical Service (EMS) were eligible for inclusion in the study. Data were extracted from national, regional or local registries.ResultsData on 10,682 confirmed OHCAs from 248 regions in 27 countries, covering an estimated population of 174 million. In 7146 (66%) cases, CPR was started by a bystander or by the EMS. The incidence of CPR attempts ranged from 19.0 to 104.0 per 100,000 population per year. 1735 had ROSC on arrival at hospital (25.2%), Overall, 662/6414 (10.3%) in all cases with CPR attempted survived for at least 30 days or to hospital discharge.ConclusionThe results of EuReCa ONE highlight that OHCA is still a major public health problem accounting for a substantial number of deaths in Europe.EuReCa ONE very clearly demonstrates marked differences in the processes for data collection and reported outcomes following OHCA all over Europe. Using these data and analyses, different countries, regions, systems, and concepts can benchmark themselves and may learn from each other to further improve survival following one of our major health care events

Differential diagnosis and cause-specific treatment during out-of-hospital cardiac arrest : a retrospective descriptive study

BackgroundThe cardiopulmonary resuscitation (CPR) guidelines recommend identifying and correcting the underlying reversible causes of out-of-hospital cardiac arrest (OHCA). However, it is uncertain how often these causes can be identified and treated. Our aim was to estimate the frequency of point of care ultrasound examinations, blood sample analyses and cause-specific treatments during OHCA.MethodsWe performed a retrospective study in a physician-staffed helicopter emergency medical service (HEMS) unit. Data on 549 non-traumatic OHCA patients who were undergoing CPR at the arrival of the HEMS unit from 2016 to 2019 were collected from the HEMS database and patient records. We also recorded the frequency of ultrasound examinations, blood sample analyses and specific therapies provided during OHCA, such as procedures or medications other than chest compressions, airway management, ventilation, defibrillation, adrenaline or amiodarone.ResultsOf the 549 patients, ultrasound was used in 331 (60%) and blood sample analyses in 136 (24%) patients during CPR. A total of 85 (15%) patients received cause-specific treatment, the most common ones being transportation to extracorporeal CPR and percutaneous coronary intervention (PCI) (n = 30), thrombolysis (n = 23), sodium bicarbonate (n = 17), calcium gluconate administration (n = 11) and fluid resuscitation (n = 10).ConclusionIn our study, HEMS physicians deployed ultrasound or blood sample analyses in 84% of the encountered OHCA cases. Cause-specific treatment was administered in 15% of the cases. Our study demonstrates the frequent use of differential diagnostic tools and relatively infrequent use of cause-specific treatment during OHCA. Effect on protocol for differential diagnostics should be evaluated for more efficient cause specific treatment during OHCA.Peer reviewe