Association of prehospital lactate levels with base excess in various emergencies - a retrospective study.

OBJECTIVES: Blood gas analysis, including parameters like lactate and base excess (BE), is crucial in emergency medicine but less commonly utilized prehospital. This study aims to elucidate the relationship between lactate and BE in various emergencies in a prehospital setting and their prognostic implications. METHODS: We conducted a retrospective analysis of prehospital emergency patients in Graz, Austria, from October 2015 to November 2020. Our primary aim was to assess the association between BE and lactate. This was assessed using Spearman's rank correlation and fitting a multiple linear regression model with lactate as the outcome, BE as the primary covariate of interest and age, sex, and medical emergency type as confounders. RESULTS: In our analysis population (n=312), lactate and BE levels were inversely correlated (Spearman's ρ, -0.75; p<0.001). From the adjusted multiple linear regression model (n=302), we estimated that a 1 mEq/L increase in BE levels was associated with an average change of -0.35 (95 % CI: -0.39, -0.30; p<0.001) mmol/L in lactate levels. Lactate levels were moderately useful for predicting mortality with notable variations across different emergency types. CONCLUSIONS: Our study highlights a significant inverse association between lactate levels and BE in the prehospital setting, underscoring their importance in early assessment and prognosis in emergency care. Additionally, the findings from our secondary aims emphasize the value of lactate in diagnosing acid-base disorders and predicting patient outcomes. Recognizing the nuances in lactate physiology is essential for effective prehospital care in various emergency scenarios.

Utilization of Multi-Parameter Blood Gas Analysis in Prehospital Emergency Medicine-A Scoping Review.

BACKGROUND: Prehospital blood gas analysis (BGA) is an evolving field that offers the potential for early identification and management of critically ill patients. However, the utility and accuracy of prehospital BGA are subjects of ongoing debate. OBJECTIVES: We aimed to provide a comprehensive summary of the current literature on prehospital BGA, including its indications, methods, and feasibility. METHODS: We performed a scoping review of prehospital BGA. A thorough search of the PubMed, Embase, and Web of Science databases was conducted to identify relevant studies focusing on prehospital BGA in adult patients. RESULTS: Fifteen studies met the inclusion criteria. Prehospital BGA was most frequently performed in patients in out-of-hospital cardiac arrest, followed by traumatic and nontraumatic cases. The parameters most commonly analyzed were pH, pCO2, pO2, and lactate. Various sampling methods, including arterial, venous, and intraosseous, were reported for prehospital BGA. While prehospital BGA shows promise in facilitating early identification of critical patients and guiding resuscitation efforts, logistical challenges are to be considered. The handling of preclinical BGA is described as feasible and useful in most of the included studies. CONCLUSION: Prehospital BGA holds significant potential for enhancing patient care in the prehospital setting, though technical challenges need to be considered. However, further research is required to establish optimal indications and demonstrate the benefits for prehospital BGA in specific clinical contexts.

Out-of-Hospital Arterial to End-Tidal Carbon Dioxide Gradient in Patients With Return of Spontaneous Circulation After Out-of-Hospital Cardiac Arrest: A Retrospective Study.

STUDY OBJECTIVE: End-tidal carbon dioxide (etCO2) is used to guide ventilation after achieving return of spontaneous circulation (ROSC) in certain out-of-hospital systems, despite an unknown difference between arterial and end-tidal CO2 (partial pressure of carbon dioxide [paCO2]-etCO2 difference) levels in this population. The primary aim of this study was to evaluate and quantify the paCO2-etCO2 difference in out-of-hospital patients with ROSC after nontraumatic cardiac arrest. METHODS: This retrospective single-center study included patients aged 18 years and older with sustained ROSC after nontraumatic out-of-hospital cardiac arrest. In patients with an existing out-of-hospital arterial blood gas analysis within 30 minutes after achieving ROSC, matching etCO2 values were evaluated. Linear regression and Bland-Altman plot analysis were performed to ascertain the primary endpoint of interest. RESULTS: We included data of 60 patients in the final analysis. The mean paCO2-etCO2 difference was 32 (±18) mmHg. Only a moderate correlation (R2=0.453) between paCO2 and etCO2 was found. Bland-Altman analysis showed a bias of 32 mmHg (95% confidence interval [CI], 27 to 36) [the upper limit of agreement of 67 mmHg (95% CI, 59 to 74) and the lower limit of agreement of -3 mmHg (95% CI, -11 to 5)]. CONCLUSION: The paCO2-etCO2 difference in patients with ROSC after out-of-hospital cardiac arrest is far from physiologic ranges, and the between-patient variability is high. Therefore, etCO2-guided adaption of ventilation might not provide adequate accuracy in this setting.

Hyperkalaemia in bleeding trauma patients: A potential marker of disease severity - A retrospective cohort study.

Background: Hyperkalaemia is a common electrolyte abnormality seen in critically ill patients. In haemorrhagic shock, it may contribute to cardiac arrest and has been identified as a potential marker for tissue hypoxia. However, the significance of its role in haemorrhagic shock and its contribution to mortality remains unclear. This study aimed to examine the potential underlying pathophysiology and evaluate the incidence and characteristics of patients with hyperkalaemia on hospital arrival in bleeding trauma patients before transfusions and its mortality. Methods: A retrospective cohort study was conducted on adult patients with traumatic bleeding admitted to a European Major Trauma Centre between January 2016 and December 2021. Patients were classified according to their serum potassium levels on arrival, and relevant clinical parameters between non-hyperkalaemic and hyperkalaemic patients were compared. Results: Among the 83 patients in this study, 8 (9.6 %) presented with hyperkalaemia on arrival. The median shock index showed a higher tendency in the hyperkalaemic group. Hyperkalaemia was found to be more common among younger patients who sustained penetrating trauma. Mortality rates were higher in the hyperkalaemic group, but the difference was not statistically significant. Conclusion: Our results suggest that hyperkalaemia occurs frequently in bleeding trauma patients on hospital arrival pre-transfusions, indicating a more severe illness. Our findings provide insights into the pathophysiology and characteristics of hyperkalaemia in bleeding trauma patients. Further studies are required to investigate the mechanisms by which hyperkalaemia contributes to mortality in haemorrhagic shock patients.

Use of bitemporal NACA score documentation in prehospital emergency medical services- a retrospective study.

BACKGROUND: The assessment of illness severity in the prehospital setting is essential for guiding appropriate medical interventions. The National Advisory Committee for Aeronautics (NACA) score is a validated tool commonly used for this purpose. However, the potential benefits of using bitemporal documentation of NACA scores to capture the dynamic changes in emergency situations remain uncertain. The objective of this study was to evaluate the potential benefit of bitemporal NACA score documentation in the prehospital setting, specifically in assessing the dynamic changes of emergencies and facilitating quality improvement through enhanced documentation practices. METHODS: In this retrospective study, data from prehospital emergency patients were analyzed who received care from the physician response unit between January 1, 2018, and May 31, 2021. Patient demographics, NACA scores, indications for emergency care, and changes in NACA scores were extracted from medical records. Statistical analyses were performed to examine the associations between NACA scores, emergency categories, indications, and changes in NACA scores. RESULTS: The study included 4005 patients, predominantly categorized as NACA III (33.7% at initial assessment, 41.8% at subsequent assessment) and NACA IV (31.6% at initial assessment, 22.4% at subsequent assessment). There was a significant improvement in NACA scores during the provision of prehospital care (p < 0.01). Notably, prehospital emergencies attributed to internal medical, neurological, traumatic, and paediatric causes demonstrated significant improvements in NACA scores (p < 0.01). Gender-specific differences were also observed. CONCLUSION: Our study suggests that the bitemporal documentation of NACA scores can be advantageous in the prehospital setting and may have implications for research, practice, and policy.

Is time to first CT scan in patients with isolated severe traumatic brain injury prolonged when prehospital arterial cannulation is performed? A retrospective non-inferiority study.

BACKGROUND: Invasive blood pressure measurement is the in-hospital gold standard to guide hemodynamic management and consecutively cerebral perfusion pressure in patients with traumatic brain injury (TBI). Its prehospital use is controversial since it may delay further care. The primary aim of this study was to test the hypothesis that patients with severe traumatic brain injury who receive prehospital arterial cannulation, compared to those with in-hospital cannulation, do not have a prolonged time between on-scene arrival and first computed tomography (CT) of the head by more than ten minutes. METHODS: This retrospective study included patients 18 years and older with isolated severe TBI and prehospital induction of emergency anaesthesia who received treatment in the resuscitation room of the University Hospital of Graz between January 1st, 2015, and December 31st, 2022. A Wilcoxon rank-sum test was used to test for non-inferiority (margin = ten minutes) of the time interval between on-scene arrival and first head CT. RESULTS: We included data of 181 patients in the final analysis. Prehospital arterial line insertion was performed in 87 patients (48%). Median (25-75th percentile) durations between on-scene arrival and first head CT were 73 (61-92) min for prehospital arterial cannulation and 75 (60-93) min for arterial cannulation in the resuscitation room. Prehospital arterial line insertion was significantly non-inferior within a margin of ten minutes with a median difference of 1 min (95% CI - 6 to 7, p = 0.003). CONCLUSION: Time-interval between on-scene arrival and first head CT in patients with isolated severe traumatic brain injury who received prehospital arterial cannulation was not prolonged compared to those with in-hospital cannulation. This supports early out-of-hospital arterial cannulation performed by experienced providers.

PerIoperative iNflammatory reSponse assessment In hiGH-risk patienTs undergoing non-cardiac surgery (INSIGHT): study protocol of a prospective non-interventional observational study.

INTRODUCTION: Increased inflammatory processes after non-cardiac surgery are very common. The association between postoperative inflammation and the occurrence of cardiovascular complications after non-cardiac surgery are still not entirely clear. Therefore, we will evaluate the association between postoperative inflammation and the occurrence of major cardiovascular complications in patients at-risk for cardiovascular complications undergoing non-cardiac surgery. We will further evaluate the association of postoperative inflammation and days-at-home within 30 days after surgery (DAH30), the incidence of acute kidney injury, postoperative N-terminal probrain natriuretic peptide (NT-proBNP) concentrations and neurocognitive decline. METHODS AND ANALYSIS: In this multicentre study, we will include 1400 patients at-risk for cardiovascular complications undergoing non-cardiac surgery. Our primary aim is to evaluate the association of postoperative maximum C-reactive protein concentration and the occurrence of a composite of five major cardiovascular complications (myocardial infarction, myocardial injury after non-cardiac surgery, new onset of atrial fibrillation, stroke and death) within 30 days after surgery using a Mann-Whitney-U test as well as a logistic regression model. As our secondary aim, we will evaluate the association of a composite of three inflammatory biomarkers (interleukin 6, procalcitonin and copeptin) on the occurrence of our composite of five cardiovascular complications within 30 days and 1 year after surgery, acute kidney injury, DAH30 and NT-proBNP concentrations using linear or logistic regression models. We will measure inflammatory biomarkers before surgery, and on the first, second, third and fifth postoperative day. We will check medical records and conduct a telephone survey 30 days and 1 year after surgery. We evaluate neurocognitive function, using a Montreal Cognitive Assessment, before and 1 year after surgery. ETHICS AND DISSEMINATION: This study was approved by the ethics committees at the Medical University of Vienna (2458/2020) and at the Medical University of Graz (33-274 ex 20/21). TRIAL REGISTRATION NUMBER: NCT04753307.

Association of immediate versus delayed extubation of patients admitted to intensive care units postoperatively and outcomes: A retrospective study.

AIM OF THIS STUDY: This study seeks to investigate, whether extubation of tracheally intubated patients admitted to intensive care units (ICU) postoperatively either immediately at the day of admission (day 1) or delayed at the first postoperative day (day 2) is associated with differences in outcomes. MATERIALS AND METHODS: We performed a retrospective analysis of data from an Austrian ICU registry. Adult patients admitted between January 1st, 2012 and December 31st, 2019 following elective and emergency surgery, who were intubated at the day 1 and were extubated at day 1 or day 2, were included. We performed logistic regression analyses for in-hospital mortality and over-sedation or agitation following extubation. RESULTS: 52 982 patients constituted the main study population. 1 231 (3.3%) patients extubated at day 1 and 958 (5.9%) at day 2 died in hospital, 464 (1.3%) patients extubated at day 1 and 613 (3.8%) at day 2 demonstrated agitation or over-sedation after extubation during ICU stay; OR (95% CI) for in-hospital mortality were OR 1.17 (1.01-1.35, p = 0.031) and OR 2.15 (1.75-2.65, p<0.001) for agitation or over-sedation. CONCLUSIONS: We conclude that immediate extubation as soon as deemed feasible by clinicians is associated with favourable outcomes and may thus be considered preferable in tracheally intubated patients admitted to ICU postoperatively.

Mechanical ventilation with ten versus twenty breaths per minute during cardio-pulmonary resuscitation for out-of-hospital cardiac arrest: A randomised controlled trial.

AIM OF THE STUDY: This study sought to assess the effects of increasing the ventilatory rate from 10 min-1 to 20 min-1 using a mechanical ventilator during cardio-pulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) on ventilation, acid-base-status, and outcomes. METHODS: This was a randomised, controlled, single-centre trial in adult patients receiving CPR including advanced airway management and mechanical ventilation offered by staff of a prehospital physician response unit (PRU). Ventilation was conducted using a turbine-driven ventilator (volume-controlled ventilation, tidal volume 6 ml per kg of ideal body weight, positive end-expiratory pressure (PEEP) 0 mmHg, inspiratory oxygen fraction (FiO2) 100%), frequency was pre-set at either 10 or 20 breaths per minute according to week of randomisation. If possible, an arterial line was placed and blood gas analysis was performed. RESULTS: The study was terminated early due to slow recruitment. 46 patients (23 per group) were included. Patients in the 20 min-1 group received higher expiratory minute volumes [8.8 (6.8-9.9) vs. 4.9 (4.2-5.7) litres, p < 0.001] without higher mean airway pressures [11.6 (9.8-13.6) vs. 9.8 (8.5-12.0) mmHg, p = 0.496] or peak airway pressures [42.5 (36.5-45.9) vs. 41.4 (32.2-51.7) mmHg, p = 0.895]. Rates of ROSC [12 of 23 (52%) vs. 11 of 23 (48%), p = 0.768], median pH [6.83 (6.65-7.05) vs. 6.89 (6.80-6.97), p = 0.913], and median pCO2 [78 (51-105) vs. 86 (73-107) mmHg, p > 0.999] did not differ between groups. CONCLUSION: 20 instead of 10 mechanical ventilations during CPR increase ventilation volumes per minute, but do not improve CO2 washout, acidaemia, oxygenation, or rate of ROSC. CLINICALTRIALS: gov Identifier: NCT04657393.

Assessing the weak links - Necessity and impact of regional cardiac arrest awareness campaigns for laypersons.

Introduction: Public knowledge of out-of-hospital cardiac arrest (OHCA), and initiation of basic life support (BLS) is crucial to increase survival in OHCA. Methods: The study analysed the knowledge and willingness to perform BLS of laypersons passing an AED at a public train station. Interviewees were recruited at two time points before and after a four year-long structured regional awareness campaign, which focused on call, compress, shock in a mid-size European city (270,000 inhabitants). Complete BLS was defined as multiple responses for call for help; initiation of chest compressions; and usage of an AED, without mentioning recovery position. Minimal BLS was defined as call for help and initiation of chest compressions. Results: A total of 784 persons were interviewed, 257 at baseline and 527 post-campaign. Confronted with a fictional OHCA, at baseline 8.5% of the interviewees spontaneously mentioned actions for complete BLS and 17.9% post-campaign (p = 0.009). An even larger increase in knowledge was seen in minimal BLS (34.6% vs 60.6%, p < 0.001). Conclusion: After a regional cardiac arrest awareness campaign, we found an increase in knowledge of BLS actions in the lay public. However, our investigation revealed severe gaps in BLS knowledge, possibly resulting in weak first links of the chain of survival.

A retrospective cohort study on association of age and physician decision making for or against rapid sequence intubation in unconscious patients.

In unconscious individuals, rapid sequence intubation (RSI) may be necessary for cardiopulmonary stabilisation and avoidance of secondary damage. Opinions on such invasive procedures in people of older age vary. We thus sought to evaluate a possible association between the probability of receiving prehospital RSI in unconsciousness and increasing age. We conducted a retrospective study in all missions (traumatic and non-traumatic) of the prehospital emergency physician response unit in Graz between January 1st, 2010 and December 31st, 2019, which we searched for Glasgow Coma Scale (GCS) below 9. Cardiac arrests were excluded. We performed multivariable regression analysis for RSI with age, GCS, independent living, and suspected cause as independent variables. Of the 769 finally included patients, 256 (33%) received RSI, whereas 513 (67%) did not. Unadjusted rates of RSI were significantly lower in older patients (aged 85 years and older) compared to the reference group aged 50-64 years (13% vs. 51%, p < 0.001). In multivariable regression analysis, patients aged 85 years and older were also significantly less likely to receive RSI [OR (95% CI) 0.76 (0.69-0.84)]. We conclude that advanced age, especially 85 years or older, is associated with significantly lower odds of receiving prehospital RSI in cases of unconsciousness.

Evaluation of the usefulness of non-invasive serum haemoglobin measurement in a perioperative setting in a prospective observational study.

Patient Blood Management (PBM) programmes seek to reduce the number of missed anaemic patients in the run-up to surgery. The aim of this study was to evaluate the usefulness of haemoglobin (Hb) measured non-invasively (SpHb) in preoperative screening for anaemia. We conducted a prospective observational study in a preoperative clinic. Adult patients undergoing examination for surgery who had their Hb measured by laboratory means also had their Hb measured non-invasively by a trained health care provider. 1216 patients were recruited. A total of 109 (9.3%) patients (53 men and 56 women) was found to be anaemic by standard laboratory Hb measurement. Sensitivity for SpHb to detect anaemic patients was 0.50 (95% CI 0.37-0.63) in women and 0.30 (95% CI 0.18-0.43) in men. Specificity was 0.97 (95% CI 0.95-0.98) in men and 0.93 (95% CI 0.84-1.0) in women. The rate of correctly classified patients was 84.7% for men and 89.4% for women. Positive predictive value for SpHb was 0.50 (95% CI 0.35-0.65) in men and 0.40 (95% CI 0.31-0.50) in women; negative predictive value was 0.93 (95% CI 0.92-0.94) in men and 0.95 (95% CI 0.94-0.96) in women. We conclude that due to low sensitivity, SpHb is poorly suitable for detecting preoperative anaemia in both sexes under standard of care conditions.