Development and internal validation of an algorithm for estimating mortality in patients encountered by physician-staffed helicopter emergency medical services.

BACKGROUND: Severity of illness scoring systems are used in intensive care units to enable the calculation of adjusted outcomes for audit and benchmarking purposes. Similar tools are lacking for pre-hospital emergency medicine. Therefore, using a national helicopter emergency medical services database, we developed and internally validated a mortality prediction algorithm. METHODS: We conducted a multicentre retrospective observational register-based cohort study based on the patients treated by five physician-staffed Finnish helicopter emergency medical service units between 2012 and 2019. Only patients aged 16 and over treated by physician-staffed units were included. We analysed the relationship between 30-day mortality and physiological, patient-related and circumstantial variables. The data were imputed using multiple imputations employing chained equations. We used multivariate logistic regression to estimate the variable effects and performed derivation of multiple multivariable models with different combinations of variables. The models were combined into an algorithm to allow a risk estimation tool that accounts for missing variables. Internal validation was assessed by calculating the optimism of each performance estimate using the von Hippel method with four imputed sets. RESULTS: After exclusions, 30 186 patients were included in the analysis. 8611 (29%) patients died within the first 30 days after the incident. Eleven predictor variables (systolic blood pressure, heart rate, oxygen saturation, Glasgow Coma Scale, sex, age, emergency medical services vehicle type [helicopter vs ground unit], whether the mission was located in a medical facility or nursing home, cardiac rhythm [asystole, pulseless electrical activity, ventricular fibrillation, ventricular tachycardia vs others], time from emergency call to physician arrival and patient category) were included. Adjusted for optimism after internal validation, the algorithm had an area under the receiver operating characteristic curve of 0.921 (95% CI 0.918 to 0.924), Brier score of 0.097, calibration intercept of 0.000 (95% CI -0.040 to 0.040) and slope of 1.000 (95% CI 0.977 to 1.023). CONCLUSIONS: Based on 11 demographic, mission-specific, and physiologic variables, we developed and internally validated a novel severity of illness algorithm for use with patients encountered by physician-staffed helicopter emergency medical services, which may help in future quality improvement.

Association among blood pressure, end-tidal carbon dioxide, peripheral oxygen saturation and mortality in prehospital post-resuscitation care.

Aim: Post-resuscitation care is described as the fourth link in a chain of survival in resuscitation guidelines. However, data on prehospital post-resuscitation care is scarce. We aimed to examine the association among systolic blood pressure (SBP), peripheral oxygen saturation (SpO2) and end-tidal carbon dioxide (EtCO2) after prehospital stabilisation and outcome among patients resuscitated from out-of-hospital cardiac arrest (OHCA). Methods: In this retrospective study, we evaluated association of the last measured prehospital SBP, SpO2 and EtCO2 before patient handover with 30-day and one-year mortality in 2,611 patients receiving prehospital post-resuscitation care by helicopter emergency medical services in Finland. Statistical analyses were completed through locally estimated scatterplot smoothing (LOESS) and multivariable logistic regression. The regression analyses were adjusted by sex, age, initial rhythm, bystander CPR, and time interval from collapse to the return of spontaneous circulation (ROSC). Results: Mortality related to SBP and EtCO2 values were U-shaped and lowest at 135 mmHg and 4.7 kPa, respectively, whereas higher SpO2 shifted towards lower mortality. In adjusted analyses, increased 30-day mortality and one year mortality was observed in patients with SBP < 100 mmHg (OR 1.9 [95% CI 1.4-2.4]) and SBP < 100 (OR 1.8 [1.2-2.6]) or EtCO2 < 4.0 kPa (OR 1.4 [1.1-1.5]), respectively. SpO2 was not significantly associated with either 30-day or one year mortality. Conclusions: After prehospital post-resuscitation stabilization, SBP < 100 mmHg and EtCO2 < 4.0 kPa were observed to be independently associated with higher mortality. The optimal targets for prehospital post-resuscitation care need to be established in the prospective studies.

Consultation Processes With Helicopter Emergency Medical Service Physicians in Finnish Prehospital Emergency Care: The Paramedics' Perspective.

OBJECTIVE: The Finnish emergency medical services operates mainly with highly educated paramedic-staffed units. Helicopter emergency medical services (HEMS) physicians alongside other physicians provide consultations to paramedics on the scene without the physician physically participating in the mission. We examined the Finnish paramedics' views regarding the consultation processes involving HEMS physicians. METHODS: This was a cross-sectional survey study among paramedics (n = 200). Assessments of the performance of HEMS physicians and other physicians in the consultation process were analyzed descriptively. The effect of the physician being expressly part of the HEMS was analyzed with inductive content analysis. RESULTS: Overall, consultations with the HEMS physician were well received among paramedics, and the HEMS physicians received higher assessments than other physicians. The familiarity with the prehospital environment, limitations, and local possibilities was valued. Expertise is particularly valuable in challenging emergency medical services missions but unnecessary in many nonurgent missions. There is scope for improvement in the attitudes and technical fluency of the consultation processes of HEMS physicians. CONCLUSION: Using HEMS physicians in prehospital consultations could be recommended. Further studies are still needed to ensure the efficacy and efficiency of the consultation process and explore the integration of video connections into current consultation practices.

Hospital-administered ECPR for out-of-hospital cardiac arrest: an observational cohort study.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) is a treatment method for refractory out-of-hospital cardiac arrest (OHCA) requiring a complex chain of care. METHODS: All cases of OHCA between 1 January 2016 and 31 December 2021 in the Helsinki University Hospital catchment area in which the ECPR protocol was activated were included in the study. The protocol involved patient transport from the emergency site with ongoing mechanical cardiopulmonary resuscitation (CPR) directly to the cardiac catheterisation laboratory where the implementation of extracorporeal membrane oxygenation (ECMO) was considered. Cases of hypothermic cardiac arrest were excluded. The main outcomes were the number of ECPR protocol activations, duration of prehospital and in-hospital time intervals, and whether the ECPR candidates were treated using ECMO or not. RESULTS: The prehospital ECPR protocol was activated in 73 cases of normothermic OHCA. The mean patient age (SD) was 54 (±11) years and 67 (91.8%) of them were male. The arrest was witnessed in 67 (91.8%) and initial rhythm was shockable in 61 (83.6%) cases. The median ambulance response time (IQR) was 9 (7-11) min. All patients received mechanical CPR, epinephrine and/or amiodarone. Seventy (95.9%) patients were endotracheally intubated. The median (IQR) highest prehospital end-tidal CO2 was 5.5 (4.0-6.9) kPa.A total of 37 (50.7%) patients were treated with venoarterial ECMO within a median (IQR) of 84 (71-105) min after the arrest. Thirteen (35.1%) of them survived to discharge and 11 (29.7%) with a cerebral performance category (CPC) 1-2. In those ECPR candidates who did not receive ECMO, 8 (22.2%) received permanent return of spontaneuous circulation during transport or immediately after hospital arrival and 6 (16.7%) survived to discharge with a CPC 1-2. CONCLUSIONS: Half of the ECPR protocol activations did not lead to ECMO treatment. However, every fourth ECPR candidate and every third patient who received ECMO-facilitated resuscitation at the hospital survived with a good neurological outcome.

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

BACKGROUND: The 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. METHODS: We 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. RESULTS: Of 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). CONCLUSION: In 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.

Multifaceted implementation and sustainability of a protocol for prehospital anaesthesia: a retrospective analysis of 2115 patients from helicopter emergency medical services.

BACKGROUND: Prehospital emergency anaesthesia (PHEA) is a high-risk procedure. We developed a prehospital anaesthesia protocol for helicopter emergency medical services (HEMS) that standardises the process and involves ambulance crews as active team members to increase efficiency and patient safety. The aim of the current study was to evaluate this change and its sustainability in (i) on-scene time, (ii) intubation first-pass success rate, and (iii) protocol compliance after a multifaceted implementation process. METHODS: The protocol was implemented in 2015 in a HEMS unit and collaborating emergency medical service systems. The implementation comprised dissemination of information, lectures, simulations, skill stations, academic detailing, and cognitive aids. The methods were tailored based on implementation science frameworks. Data from missions were gathered from mission databases and patient records. RESULTS: During the study period (2012-2020), 2381 adults underwent PHEA. The implementation year was excluded; 656 patients were analysed before and 1459 patients after implementation of the protocol. Baseline characteristics and patient categories were similar. On-scene time was significantly redused after the implementation (median 32 [IQR 25-42] vs. 29 [IQR 21-39] minutes, p < 0.001). First pass success rate increased constantly during the follow-up period from 74.4% (95% CI 70.7-77.8%) to 97.6% (95% CI 96.7-98.3%), p = 0.0001. Use of mechanical ventilation increased from 70.6% (95% CI 67.0-73.9%) to 93.4% (95% CI 92.3-94.8%), p = 0.0001, and use of rocuronium increased from 86.4% (95% CI 83.6-88.9%) to 98.5% (95% CI 97.7-99.0%), respectively. Deterioration in compliance indicators was not observed. CONCLUSIONS: We concluded that clinical performance in PHEA can be significantly improved through multifaceted implementation strategies.

Association between physician's case volume in prehospital advanced trauma care and 30-day mortality: A registry-based analysis of 4,032 patients.

BACKGROUND: Seriously injured patients may benefit from prehospital interventions provided by a critical care physician. The relationship between case volume and outcome has been established in trauma teams in hospitals, as well as in prehospital advanced airway management. In this study, we aimed to assess if a volume-outcome relationship exists in prehospital advanced trauma care. METHODS: We performed a retrospective cohort study using the national helicopter emergency medical services database, including trauma patients escorted from scene to hospital by a helicopter emergency medical services physician during January 1, 2013, to August 31, 2019. In addition, similar cases during 2012 were used to determine case volumes. We performed a multivariate logistic regression analysis, with 30-day mortality as the outcome. Age, sex, Glasgow Coma Scale, shock index, mechanism of injury, time interval from alarm to the patient and duration of transport, level of receiving hospital, and physician's trauma case volume were used as covariates. On-scene times, interventions performed, and status at hospital arrival were assessed in patients who were grouped according to physician's case volume. RESULTS: In total, 4,032 escorted trauma patients were included in the study. The median age was 40.2 (22.9-59.3) years, and 3,032 (75.2%) were male. Within 30 days, 498 (13.2%) of these patients had died. In the highest case volume group, advanced interventions were performed more often, and patients were less often hypotensive at handover. Data for multivariate analysis were available for 3,167 (78.5%) of the patients. Higher case volume was independently associated with lower mortality (odds ratio, 0.59; 95% confidence interval, 0.38-0.89). CONCLUSION: When a prehospital physician's case volume is higher in high-risk prehospital trauma, this seems to be associated with more active practice patterns and significantly lower 30-day mortality. The quality of prehospital critical care could be increased by ensuring sufficient case volume for the providers of such care. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

The effect of time of measurement on the discriminant ability for mortality in trauma of a pre-hospital shock index multiplied by age and divided by the Glasgow Coma Score: a registry study.

BACKGROUND: The shock index (SI) and its derivatives have been shown to predict mortality in severely injured patients, both in pre-hospital and in-hospital settings. However, the impact of the time of measurement on the discriminative ability of the pre-hospital SI is unknown. The aim of this study was to evaluate whether the time of measurement influences the discriminative ability of the SI multiplied by age (SIA) and divided by the Glasgow Coma Score (SIA/G). METHODS: Registry data were obtained from the national helicopter emergency medical services (HEMS) on trauma patients aged ≥ 18 years. The SI values were calculated based on the first measured vitals of the trauma patients by the HEMS unit. The discriminative ability of the SIA/G, with 30-day mortality as the endpoint, was evaluated according to different delay times (0 - 19, 20 - 39 and ≥ 40 min) from the initial incident. Sub-group analyses were performed for trauma patients without a traumatic brain injury (TBI), patients with an isolated TBI and patients with polytrauma, including a TBI. RESULTS: In total, 3,497 patients were included in the study. The SIA/G was higher in non-survivors (median 7.8 [interquartile range 4.7-12.3] vs. 2.4 [1.7-3.6], P < 0.001). The overall area under the receiver operator characteristic curve (AUROC) for the SIA/G was 0.87 (95% CI: 0.85-0.89). The AUROC for the SIA/G was similar in the short (0.88, 95% CI: 0.85-0.91), intermediate (0.86, 95% CI: 0.84-0.89) and long (0.86, 95% CI: 0.82-0.89) measurement delay groups. The findings were similar in the three trauma sub-groups. CONCLUSIONS: The discriminative ability of the SIA/G in predicting 30-day mortality was not significantly affected by the measurement time of the index in the pre-hospital setting. The SIA/G is a simple and reliable tool for assessing the risk of mortality among severely injured patients in the pre-hospital setting.

Predictive value of shock index variants on 30-day mortality of trauma patients in helicopter emergency medical services: a nationwide observational retrospective multicenter study.

The original shock index (SI) has been further developed to increase its prognostic value. We aimed to evaluate the predictive value of different SI variants on 30-day mortality among severely injured trauma patients in pre-hospital critical care settings. Adult trauma patients in the national Helicopter Emergency Medical Services (HEMS) registry were evaluated based on the primary outcome of 30-day mortality. SI, SIA (SI multiplied by age), SI/G (SI divided by Glasgow Coma Scale (GCS)), SIA/G (SI multiplied by age and divided by GCS), and SS (SI divided by oxygen saturation) were calculated based on the first vital signs measured at the time of HEMS contact. The area under the receiver operating curve (AUROC) was calculated for each SI variant. In total 4108 patients were included in the study. The overall 30-day mortality was 13.5%. The SIA/G and SI/G had the highest predictive ability (AUROC 0.884 [95% CI 0.869-0.899] and 0.8000 [95% CI 0.7780-0.8239], respectively). The SIA/G yielded good predictive performance between 30-day survivors and non-survivors in the pre-hospital critical care setting.

Intubation first-pass success in a high performing pre-hospital critical care system is not associated with 30-day mortality: a registry study of 4496 intubation attempts.

BACKGROUND: Lower intubation first-pass success (FPS) rate is associated with physiological deterioration, and FPS is widely used as a quality indicator of the airway management of a critically ill patient. However, data on FPS's association with survival is limited. We aimed to investigate if the FPS rate is associated with 30-day mortality or physiological complications in a pre-hospital setting. Furthermore, we wanted to describe the FPS rate in Finnish helicopter emergency medical services. METHODS: This was a retrospective observational study. Data on drug-facilitated intubation attempts by helicopter emergency medical services were gathered from a national database and analysed. Multivariate logistic regression, including known prognostic factors, was performed to assess the association between FPS and 30-day mortality, collected from population registry data. RESULTS: Of 4496 intubation attempts, 4082 (91%) succeeded on the first attempt. The mortality rates in FPS and non-FPS patients were 34% and 38% (P = 0.21), respectively. The adjusted odds ratio of FPS for 30-day mortality was 0.88 (95% CI 0.66-1.16). Hypoxia after intubation and at the time of handover was more frequent in the non-FPS group (12% vs. 5%, P < 0.001, and 5% vs. 3%, P = 0.01, respectively), but no significant differences were observed regarding other complications. CONCLUSION: FPS is not associated with 30-day mortality in pre-hospital critical care delivered by advanced providers. It should therefore be seen more as a process quality indicator instead of a risk factor of poor outcome, at least considering the current limitations of the parameter.

Accuracy of prehospital clinicians' perceived prognostication of long-term survival in critically ill patients: a nationwide retrospective cohort study on helicopter emergency service patients.

OBJECTIVES: Prehospital critical care physicians regularly attend to patients with poor prognosis and may limit the advanced therapies. The aim of this study was to evaluate the accuracy of poor prognosis given by prehospital critical care clinicians. DESIGN: Cohort study. SETTING: We performed a retrospective cohort study using the national helicopter emergency medical services (HEMS) quality database. PARTICIPANTS: Patients classified by the HEMS clinician to have survived until hospital admission solely because of prehospital interventions but evaluated as having no long-term survival by prehospital clinician, were included. PRIMARY AND SECONDARY OUTCOME: The survival of the study patients was examined at 30 days, 1 year and 3 years. RESULTS: Of 36 715 patients encountered by the HEMS during the study period, 2053 patients were classified as having no long-term survival and included. At 30 days, 713 (35%, 95% CI 33% to 37%) were still alive and 69 were lost to follow-up. Furthermore, at 1 year 524 (26%) and at 3 years 267 (13%) of the patients were still alive. The deceased patients received more often prehospital rapid sequence intubation and vasoactives, compared with patients alive at 30 days. Patients deceased at 30 days were older and had lower initial Glasgow Coma Scores. Otherwise, no clinically relevant difference was found in the prehospital vital parameters between the survivors and non-survivors. CONCLUSIONS: The prognostication of long-term survival for critically ill patients by a prehospital critical care clinician seems to fulfil only moderately. A prognosis based on clinical judgement must be handled with a great degree of caution and decision on limitation of advanced care should be made cautiously.

Standardised data collection in prehospital critical care: a comparison of medical problem categories and discharge diagnoses.

BACKGROUND: Prehospital medical problem reporting is essential in the management of helicopter emergency medical services (HEMS) operations. The consensus-based template for reporting and documenting in physician-staffed prehospital services exists and the classification of medical problems presented in the template is widely used in research and quality improvement. However, validation of the reported prehospital medical problem is lacking. This study aimed to describe the in-hospital diagnoses, patient characteristics and medical interventions in different categories of medical problems. METHODS: This retrospective, observational registry study examined the 10 most common in-hospital International Statistical Classification of Disease (ICD-10) diagnoseswithin different prehospital medical problem categories, defined by the HEMS physician/paramedic immediately after the mission was completed. Data were gathered from a national HEMS quality registry and a national hospital discharge registry. Patient characteristics and medical interventions related to different medical problem categories are also described. RESULTS: A total of 33,844 patients were included in the analyses. All the medical problem categories included a broad spectrum of ICD-10 diagnoses (the number of diagnosis classes per medical problem category ranged from 73 to 403). The most frequent diagnoses were mainly consistent with the reported medical problems. Overlapping of ICD-10 diagnoses was mostly seen in two medical problem categories: stroke and acute neurology excluding stroke. Additionally, typical patient characteristics and disturbances in vital signs were related to adequate medical problem categories. CONCLUSIONS: Medical problems reported by HEMS personnel have adequate correspondence to hospital discharge diagnoses. However, the classification of cerebrovascular accidents remains challenging.

Cerebral oxygen desaturation events during and functional outcomes after prehospital anaesthesia: A prospective pilot study.

BACKGROUND: During prehospital anaesthesia, oxygen delivery to the brain might be inadequate to match the oxygen consumption, with unknown long-term functional outcomes. We aimed to evaluate the feasibility of monitoring cerebral oxygenation during prehospital anaesthesia and determining the long-term outcomes. METHODS: We performed a prospective observational feasibility study in two helicopter emergency medical services units. Frontal lobe regional oxygen saturation (rSO2 ) of adult patients undergoing prehospital anaesthesia was monitored with near-infrared spectroscopy (NIRS) by a Nonin H500 oximeter. The outcome was evaluated with a modified Rankin Scale (mRS) at 30 days and 1 year. Health-related quality of life (HRQoL) was measured with a 15D instrument at 1 year. RESULTS: Of 101 patients enrolled, 83 were included. The mean baseline rSO2 was 79% (73-84). Desaturation for at least 5 min to rSO2 below 50% or a decrease of 10% from baseline occurred in four (5%, 95% CI 2%-12%) and 19 (23%, 95% CI 15-93) patients. At 1 year, 32 patients (53%, 95% CI 41-65) achieved favourable neurological outcomes. The median 15D score was 0.889 (Q1-Q3, 0.796-0.970). CONCLUSION: Monitoring cerebral oxygenation with a hand-held oximeter during prehospital anaesthesia and collecting data on functional outcomes and HRQoL are feasible. Only half of the patients achieved a favourable functional outcome. The effects of cerebral oxygenation on outcomes during prehospital critical care need to be assessed in future studies.

Validation of Score to Detect Intracranial Lesions in Unconscious Patients in Prehospital Setting.

OBJECTIVES: Recognizing stroke and other intracranial pathologies in prehospital phase facilitates prompt recanalization and other specific care. Recognizing these can be difficult in patients with decreased level of consciousness. We previously derived a scoring system combining systolic blood pressure, age and heart rate to recognize patients with intracranial pathology. In this study we aimed to validate the score in a larger, separate population. MATERIALS AND METHODS: We conducted a register based retrospective study on patients ≥16 years old and Glasgow Coma Score <15 encountered by helicopter emergency medical services. Diagnoses at the end of hospitalization were used to identify if patients had intracranial lesion or not. The performance of score was evaluated by area under the receiver operating characteristics curve (AUROC). RESULTS: Of 9,309 patients included, 1,925 (20.7%) had an intracranial lesion including 1,211 cases of stroke. Older age, higher blood pressure and lower heart rate were predictors for an intracranial lesion (P<0.001 for all). The score distinguished patients with intracranial lesion with AUROC of 0.749 (95% CI 0.737 to 0.761). The performance slightly improved if only patients intubated in prehospital phase were included AUROC 0.780 (95% CI 0.770 to 0.806) or convulsion related diagnosis excluded AUROC of 0.788 (95% CI 0.768 to 0.792). CONCLUSIONS: A scoring of systolic blood pressure, heart rate and age help differentiate intracranial lesions in patients with decreased level of consciousness in prehospital care. This may facilitate direct transportation to stroke center and application of neuroprotective measures in prehospital critical care.

Effect of time intervals in critical care provided by helicopter emergency medical services on 30-day survival after trauma.

BACKGROUND: Trauma is the leading cause of death especially in children and young adults. Prehospital care following trauma emphasizes swift transport to a hospital following initial care. Previous studies have shown conflicting results regarding the effect of time on the survival following major trauma. In our study we investigated the effect of prehospital time-intervals on 30-day mortality on trauma patients that received prehospital critical care. METHODS: We performed a retrospective study on all trauma patients encountered by helicopter emergency medical services in Finland from 2012 to 2018. Patients discharge diagnoses were classed into (1) trauma without traumatic brain injury, (2) isolated traumatic brain injury and (3) trauma with traumatic brain injury. Emergency medical services response time, helicopter emergency medical services response time, on-scene time and transport time were used as time-intervals and age, Glasgow coma scale, hypotension, need for prehospital airway intervention and ICD-10 based Injury Severity Score were used as variables in logistic regression analysis. RESULTS: Mortality data was available for 4,803 trauma cases. The combined 30-day mortality was 12.1% (582/4,803). Patients with trauma without a traumatic brain injury had the lowest mortality, at 4.3% (111/2,605), whereas isolated traumatic brain injury had the highest, at 22.9% (435/1,903). Patients with both trauma and a traumatic brain injury had a mortality of 12.2% (36/295). Following adjustments, no association was observed between time intervals and 30-day mortality. DISCUSSION: Our study revealed no significant association between different timespans and mortality following severe trauma in general. Trends in odds ratios can be interpreted to favor more expedited care, however, no statistical significance was observed. As trauma forms a heterogenous patient group, specific subgroups might require different approaches regarding the prehospital timeframes. STUDY TYPE: prognostic/therapeutic/diagnostic test.

Incidence of hyperoxia and factors associated with cerebral oxygenation during cardiopulmonary resuscitation.

BACKGROUND: High oxygen levels may worsen cardiac arrest reperfusion injury. We determined the incidence of hyperoxia during and immediately after successful cardiopulmonary resuscitation and identified factors associated with intra-arrest cerebral oxygenation measured with near-infrared spectroscopy (NIRS). METHODS: A prospective observational study of out-of-hospital cardiac arrest patients treated by a physician-staffed helicopter unit. Collected data included intra-arrest brain regional oxygen saturation (rSO2) with NIRS, invasive blood pressures, end-tidal CO2 (etCO2) and arterial blood gas samples. Moderate and severe hyperoxia were defined as arterial oxygen partial pressure (paO2) 20.0-39.9 and ≥40 kPa, respectively. Intra-arrest factors correlated with the NIRS value, rSO2, were assessed with the Spearman's correlation test. RESULTS: Of 80 recruited patients, 73 (91%) patients had rSO2 recorded during CPR, and 46 had an intra-arrest paO2 analysed. ROSC was achieved in 28 patients, of whom 20 had paO2 analysed. Moderate hyperoxia was seen in one patient during CPR and in four patients (20%, 95% CI 7-42%) after ROSC. None had severe hyperoxia during CPR, and one patient (5%, 95% 0-25%) immediately after ROSC. The rSO2 during CPR was correlated with intra-arrest systolic (r = 0.28, p < 0.001) and diastolic blood pressure (p = 0.32, p < 0.001) but not with paO2 (r = 0.13, p = 0.41), paCO2 (r = 0.18, p = 0.22) or etCO2 (r = 0.008, p = 0.9). CONCLUSION: Hyperoxia during or immediately after CPR is rare in patients treated by physician-staffed helicopter units. Cerebral oxygenation during CPR appears more dependent, albeit weakly, on hemodynamics than arterial oxygen concentration.

Reasons behind failed prehospital intubation attempts while combining C-MAC videolaryngoscope and Frova introducer.

BACKGROUND: High first-pass success rate is achieved with the routine use of C-MAC videolaryngoscope and Frova introducer. We aim to identify potential reasons and subgroups associated with failed intubation attempts, analyse actions taken after them and study possible complications. METHODS: We conducted a retrospective observational study of adult intubated patients at a single helicopter emergency medical service unit in southern Finland between 2016 and 2018. We collected data on patient characteristics, reasons for failed attempts, complications and follow-up measures from a national helicopter emergency medical service database and from prehospital patient records. RESULTS: 1011 tracheal intubations were attempted. First attempt was successful in 994 cases (FPS 994/1011, 98.3%), 15 needed a second or third attempt and two a surgical airway (non-FPS 17/1011, 1.7%, 95% CI 1.0-2.7). The failed first attempt group had heterogenous characteristics. The most common cause for a failed first attempt was obstruction of the airway by vomit, food, mucus or blood (10/13, 76%). After the failed first attempt, there were six cases (6/14, 43%) of deviation from the protocol and the most frequent complications were five cases (5/17, 29%) of hypoxia and four cases (4/17, 24%) of hypotension. CONCLUSIONS: When a protocol combining the C-MAC videolaryngoscope and Frova introducer is used, the most common reason for a failed first attempt is an airway blocked by gastric content, blood or mucus. These findings highlight the importance of effective airway decontamination methods and questions the appropriateness of anatomically focused pre-intubation assessment tools when such protocol is used.

Frequency, indications and success of out-of-hospital intubations in Finnish children.

BACKGROUND: Earlier studies have shown variable results regarding the success of paediatric emergency endotracheal intubation between different settings and operators. We aimed to describe the paediatric population intubated by physician-staffed helicopter emergency medical service (HEMS) and evaluate the factors associated with overall and first-pass success (FPS). METHODS: We conducted a retrospective observational cohort study in Finland including all children less than 16 years old who required endotracheal intubation by a HEMS physician from January 2014 to August 2019. Utilising a national HEMS database, we analysed the incidence, indications, overall and first-pass success rates of endotracheal intubation. RESULTS: A total of 2731 children were encountered by HEMS, and intubation was attempted in 245 (9%); of these, 22 were younger than 1 year, 103 were aged 1-5 years and 120 were aged 6-15 years. The most common indications for airway management were cardiac arrest for the youngest age group, neurological reasons (e.g., seizures) for those aged 1-5 years and trauma for those aged 6-15. The HEMS physicians had an overall success rate of 100% (95% CI: 98-100) and an FPS rate of 86% (95% CI: 82-90). The FPS rate was lower in the youngest age group (p = .002) and for patients in cardiac arrest (p < .001). CONCLUSIONS: Emergency endotracheal intubation of children is successfully performed by a physician staffed HEMS unit even though these procedures are rare. To improve the care, emphasis should be on airway management of infants and patients in cardiac arrest.

Characteristics of Nontrauma Patients Receiving Prehospital Blood Transfusion with the Same Triggers as Trauma Patients: A Retrospective Observational Cohort Study.

Objective: While prehospital blood transfusion (PHBT) for trauma patients has been established in many services, the literature on PHBT use for nontrauma patients is limited. We aimed to describe and compare nontrauma and trauma patients receiving PHBT who had similar hemodynamic triggers. Methods: We analyzed 3.5 years of registry data from a single prehospital critical care unit. The PHBT protocol included two packed red blood cell units and was later completed with two freeze-dried plasma units. The transfusion triggers were a strong clinical suspicion of massive hemorrhage and systolic blood pressure below 90 mmHg or absent radial pulse. Results: Thirty-six nontrauma patients and 96 trauma patients received PHBT. The nontrauma group had elderly patients (median 65 [interquartile range, IQR, 56-73] vs 37 [IQR 25-57] years, p < 0.0001) and included patients with gastrointestinal bleeding (n = 15; 42%), vascular catastrophes (n = 9; 25%), postoperative bleeding (n = 6; 17%), obstetrical bleeding (n = 4; 11%) and other (n = 2; 6%). Cardiac arrest occurred in nine (25%) nontrauma and in 15 (16%) trauma patients. Of these, 5 (56%) and 10 (67%) survived to hospital admission and 3 (33%) and 2 (13%) to hospital discharge. On admission, the nontrauma patients had lower hemoglobin (median 95 [84-119] vs 124 [108-133], p < 0.0001), higher pH (median 7.40 [7.27-7.44] vs 7.30 [7.19-7.36], p = 0.0015) and lower plasma thromboplastin time (median 55 [45-81] vs 72 [58-86], p = 0.0261) than the trauma patients. Conclusions: We identified four nontrauma patient groups in need of PHBT, and the patients appeared to be seriously ill. Efficacy of prehospital transfusion in nontrauma patients should be evaluated futher in becoming studies.