Characteristics and critical care interventions in drowning patients treated by the Danish Air Ambulance from 2016 to 2021: a nationwide registry-based study with 30-day follow-up

BACKGROUND

Improving oxygenation and ventilation in drowning patients early in the field is critical and may be lifesaving. The critical care interventions performed by physicians in drowning management are poorly described. The aim was to describe patient characteristics and critical care interventions with 30-day mortality as the primary outcome in drowning patients treated by the Danish Air Ambulance.

METHODS

This retrospective cohort study with 30-day follow-up identified drowning patients treated by the Danish Air Ambulance from January 1, 2016, through December 31, 2021. Drowning patients were identified using a text-search algorithm (Danish Drowning Formula) followed by manual review and validation. Operational and medical data were extracted from the Danish Air Ambulance database. Descriptive analyses were performed comparing non-fatal and fatal drowning incidents with 30-day mortality as the primary outcome.

RESULTS

Of 16,841 dispatches resulting in a patient encounter in the six years, the Danish Drowning Formula identified 138 potential drowning patients. After manual validation, 98 drowning patients were included in the analyses, and 82 completed 30-day follow-up. The prehospital and 30-day mortality rates were 33% and 67%, respectively. The National Advisory Committee for Aeronautics severity scores from 4 to 7, indicating a critical emergency, were observed in 90% of the total population. They were significantly higher in the fatal versus non-fatal group (p < 0.01). At least one critical care intervention was performed in 68% of all drowning patients, with endotracheal intubation (60%), use of an automated chest compression device (39%), and intraosseous cannulation (38%) as the most frequently performed interventions. More interventions were generally performed in the fatal group (p = 0.01), including intraosseous cannulation and automated chest compressions.

CONCLUSIONS

The Danish Air Ambulance rarely treated drowning patients, but those treated were severely ill, with a 30-day mortality rate of 67% and frequently required critical care interventions. The most frequent interventions were endotracheal intubation, automated chest compressions, and intraosseous cannulation.

Technical Skills Curriculum in Neonatology: A Modified European Delphi Study

INTRODUCTION

Simulation-based training (SBT) aids healthcare providers in acquiring the technical skills necessary to improve patient outcomes and safety. However, since SBT may require significant resources, training all skills to a comparable extent is impractical. Hence, a strategic prioritization of technical skills is necessary. While the European Training Requirements in Neonatology provide guidance on necessary skills, they lack prioritization. We aimed to identify and prioritize technical skills for a SBT curriculum in neonatology.

METHODS

A three-round modified Delphi process of expert neonatologists and neonatal trainees was performed. In round one, the participants listed all the technical skills newly trained neonatologists should master. The content analysis excluded duplicates and non-technical skills. In round two, the Copenhagen Academy for Medical Education and Simulation Needs Assessment Formula (CAMES-NAF) was used to preliminarily prioritize the technical skills according to frequency, importance of competency, SBT impact on patient safety, and feasibility for SBT. In round three, the participants further refined and reprioritized the technical skills. Items achieving consensus (agreement of ≥75%) were included.

RESULTS

We included 168 participants from 10 European countries. The response rates in rounds two and three were 80% (135/168) and 87% (117/135), respectively. In round one, the participants suggested 1964 different items. Content analysis revealed 81 unique technical skills prioritized in round two. In round three, 39 technical skills achieved consensus and were included.

CONCLUSION

We reached a European consensus on a prioritized list of 39 technical skills to be included in a SBT curriculum in neonatology.

NON-pharmacological Approach Less Invasive Surfactant Administration (NONA-LISA) trial: protocol for a randomised controlled trial

INTRODUCTION

Using pre-procedure analgesia with the risk of apnoea may complicate the Less Invasive Surfactant Administration (LISA) procedure or reduce the effect of LISA.

METHODS

The NONA-LISA trial (ClinicalTrials.gov, NCT05609877) is a multicentre, blinded, randomised controlled trial aiming at including 324 infants born before 30 gestational weeks, meeting the criteria for surfactant treatment by LISA. Infants will be randomised to LISA after administration of fentanyl 0.5-1 mcg/kg intravenously (fentanyl group) or isotonic saline solution intravenously (saline group). All infants will receive standardised non-pharmacological comfort care before and during the LISA procedure. Additional analgesics will be provided at the clinician's discretion. The primary outcome is the need for invasive ventilation, meaning mechanical or manual ventilation via an endotracheal tube, for at least 30 min (cumulated) within 24 h of the procedure. Secondary outcomes include the modified COMFORTneo score during the procedure, bronchopulmonary dysplasia at 36 weeks, and mortality at 36 weeks.

DISCUSSION

The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice.

IMPACT

Pre-procedure analgesia is associated with apnoea and may complicate procedures that rely on regular spontaneous breathing, such as Less Invasive Surfactant Administration (LISA). This randomised controlled trial addresses the effect of analgesic premedication in LISA by comparing fentanyl with a placebo (isotonic saline) in infants undergoing the LISA procedure. All infants will receive standardised non-pharmacological comfort. The NONA-LISA trial has the potential to provide evidence for a standardised approach to relief from discomfort or pain in preterm infants during LISA and to reduce invasive ventilation. The results may affect future clinical practice regarding analgesic treatment associated with the LISA procedure.

Prehospital interventions and outcomes in traumatic cardiac arrest: a population-based cohort study using the Danish Helicopter Emergency Medical Services data

BACKGROUND AND IMPORTANCE

Traumatic cardiac arrest is associated with poor prognosis, and timely evidence-based treatment is paramount for increasing survival rates. Physician-staffed helicopter emergency medical service use in major trauma has demonstrated improved outcomes. However, the sparsity of data highlights the necessity for a comprehensive understanding of the epidemiology of traumatic cardiac arrest.

OBJECTIVES

The primary objective of the present study was to evaluate survival and return of spontaneous circulation (ROSC) and to investigate the characteristics of patients with traumatic cardiac arrest assessed by the Danish HEMS.

DESIGN

This was a population-based cohort study based on data from the Danish helicopter emergency medical service database.

SETTINGS AND PARTICIPANTS

The study included all patients assessed by the Danish helicopter emergency medical services between 2016 and 2021.

OUTCOME MEASURES AND ANALYSIS

Data were analysed using descriptive statistics, non-parametric testing and logistic regression analyses. Descriptive analysis of prehospital interventions included cardiopulmonary resuscitation, defibrillation, airway management, administration of blood products, and thoracic decompression. The primary outcome was 30-day survival, and the key secondary outcome was prehospital ROSC.

MAIN RESULTS

A total of 223 patients with TCA were included. The median age was 54 years (IQR 34-68), and the majority were males. Overall, 23% of patients achieved prehospital ROSC, and the 30-day survival rate was 4%. Factors associated with an increased likelihood of ROSC were an initial shockable cardiac rhythm, odds ratio (OR) of 3.78 (95% CI 1.33-11.00) and endotracheal intubation, OR 7.10 (95% CI 2.55-22.85).

CONCLUSION

This study highlights the low survival rates observed among patients with traumatic cardiac arrest assessed by helicopter emergency medical services. The findings support the positive impact of an initial shockable cardiac rhythm and endotracheal intubation in improving the likelihood of ROSC. The study contributes to the limited literature on traumatic cardiac arrests assessed by physician-staffed helicopter emergency services. Finally, the findings emphasise the need for further research to understand and improve outcomes in this subgroup of cardiac arrest.

Danish Drowning Formula for identification of out-of-hospital cardiac arrest from drowning

BACKGROUND

Accurate, reliable, and sufficient data is required to reduce the burden of drowning by targeting preventive measures and improving treatment. Today's drowning statistics are informed by various methods sometimes based on data sources with questionable reliability. These methods are likely responsible for a systematic and significant underreporting of drowning. This study's aim was to assess the 30-day survival of patients with out-of-hospital cardiac arrest (OHCA) identified in the Danish Cardiac Arrest Registry (DCAR) after applying the Danish Drowning Formula.

METHODS

This nationwide, cohort, registry-based study with 30-day follow-up used the Danish Drowning Formula to identify drowning-related OHCA with a resuscitation attempt from the DCAR from January 1st, 2016, through December 31st, 2021. The Danish Drowning Formula is a text-search algorithm constructed for this study based on trigger-words identified from the prehospital medical records of validated drowning cases. The primary outcome was 30-day survival from OHCA. Data were analyzed using multiple logistic regression.

RESULTS

Drowning-related OHCA occurred in 374 (1%) patients registered in the DCAR compared to 29,882 patients with OHCA from other causes. Drowning-related OHCA more frequently occurred at a public location (87% vs 25%, p < 0.001) and were more frequently witnessed by bystanders (80% vs 55%, p < 0.001). Both 30-day and 1-year survival for patients with drowning-related OHCA were significantly higher compared to OHCA from other causes (33% vs 14% and 32% vs 13%, respectively, p < 0.001). The adjusted odds ratio for 30-day survival for drowning-related OHCA and other causes of OHCA was 2.3 [1.7-3.2], p < 0.001. Increased 30-day survival was observed for drowning-related OHCA occurring at swimming pools compared to public location OHCA from other causes with an OR of 11.6 [6.0-22.6], p < 0.001.

CONCLUSIONS

This study found higher 30-day survival among drowning-related OHCA compared to OHCA from other causes. This study proposed that a text-search algorithm (Danish Drowning Formula) could explore unstructured text fields to identify drowning persons. This method may present a low-resource solution to inform the drowning statistics in the future.

REGISTRATION

This study was registered at ClinicalTrials.gov before analyses (NCT05323097).

Association between using a prehospital assessment unit and hospital admission and mortality: a matched cohort study

OBJECTIVES

This study aimed to compare hospital admission and 30-day mortality between patients assessed by the prehospital assessment unit (PAU) and patients not assessed by the PAU.

DESIGN

This was a matched cohort study.

SETTING

This study was conducted between November 2021 and October 2022 in Region Zealand, Denmark.

PARTICIPANTS

989 patients aged >18, assessed by the PAU, were identified, and 9860 patients not assessed by the PAU were selected from the emergency calls using exposure density sampling.

EXPOSURE

Patients assessed by the PAU. The PAU is operated by paramedics with access to point-of-care test facilities. The PAU is an alternative response vehicle without the capability of transporting patients.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was hospital admission within 48 hours after the initial call. The key secondary outcomes were admission within 7 days, 30-day mortality and admission within 6 hours. Descriptive statistical analyses were conducted, and logistic regression models were used to estimate adjusted OR (aOR) and 95% CI.

RESULTS

Among the PAU assessed, 44.1% were admitted within 48 hours, compared with 72.9% of the non-PAU assessed, p<0.001. The multivariable analysis showed a lower risk of admission within 48 hours and 7 days among the PAU patients, aOR 0.31 (95% CI 0.26 to 0.38) and aOR 0.50 (95% CI 0.38 to 0.64), respectively. The 30-day mortality rate was 3.8% in the PAU-assessed patients vs 5.5% in the non-PAU-assessed patients, p=0.03. In the multivariable analysis, no significant difference was found in mortality aOR 0.99 (95% CI 0.71 to 1.42). No deaths were observed in PAU-assessed patients without subsequent follow-up.

CONCLUSION

The recently introduced PAU aims for patient-centred emergency care. The PAU-assessed patients had reduced admissions within 48 hours and 7 days after the initial call. Study findings indicate that the PAU is safe since we identified no significant differences in 30-day mortality.

TRIAL REGISTRATION NUMBER

NCT05654909.

Curriculum and assessment tool for less invasive surfactant administration: an international Delphi consensus study

BACKGROUND

Training and assessment of operator competence for the less invasive surfactant administration (LISA) procedure vary. This study aimed to obtain international expert consensus on LISA training (LISA curriculum (LISA-CUR)) and assessment (LISA assessment tool (LISA-AT)).

METHODS

From February to July 2022, an international three-round Delphi process gathered opinions from LISA experts (researchers, curriculum developers, and clinical educators) on a list of items to be included in a LISA-CUR and LISA-AT (Round 1). The experts rated the importance of each item (Round 2). Items supported by more than 80% consensus were included. All experts were asked to approve or reject the final LISA-CUR and LISA-AT (Round 3).

RESULTS

A total of 153 experts from 14 countries participated in Round 1, and the response rate for Rounds 2 and 3 was >80%. Round 1 identified 44 items for LISA-CUR and 22 for LISA-AT. Round 2 excluded 15 items for the LISA-CUR and 7 items for the LISA-AT. Round 3 resulted in a strong consensus (99-100%) for the final 29 items for the LISA-CUR and 15 items for the LISA-AT.

CONCLUSIONS

This Delphi process established an international consensus on a training curriculum and content evidence for the assessment of LISA competence.

IMPACT

This international consensus-based expert statement provides content on a curriculum for the less invasive surfactant administration procedure (LISA-CUR) that may be partnered with existing evidence-based strategies to optimize and standardize LISA training in the future. This international consensus-based expert statement also provides content on an assessment tool for the LISA procedure (LISA-AT) that can help to evaluate competence in LISA operators. The proposed LISA-AT enables standardized, continuous feedback and assessment until achieving proficiency.

Traumatic cardiac arrest - a nationwide Danish study

BACKGROUND

Cardiac arrest following trauma is a leading cause of death, mandating urgent treatment. This study aimed to investigate and compare the incidence, prognostic factors, and survival between patients suffering from traumatic cardiac arrest (TCA) and non-traumatic cardiac arrest (non-TCA).

METHODS

This cohort study included all patients suffering from out-of-hospital cardiac arrest in Denmark between 2016 and 2021. TCAs were identified in the prehospital medical record and linked to the out-of-hospital cardiac arrest registry. Descriptive and multivariable analyses were performed with 30-day survival as the primary outcome.

RESULTS

A total of 30,215 patients with out-of-hospital cardiac arrests were included. Among those, 984 (3.3%) were TCA. TCA patients were younger and predominantly male (77.5% vs 63.6%, p =  < 0.01) compared to non-TCA patients. Return of spontaneous circulation occurred in 27.3% of cases vs 32.3% in non-TCA patients, p < 0.01, and 30-day survival was 7.3% vs 14.2%, p < 0.01. An initial shockable rhythm was associated with increased survival (aOR = 11.45, 95% CI [6.24 - 21.24] in TCA patients. When comparing TCA with non-TCA other trauma and penetrating trauma were associated with lower survival (aOR: 0.2, 95% CI [0.02-0.54] and aOR: 0.1, 95% CI [0.03 - 0.31], respectively. Non-TCA was associated with an aOR: 3.47, 95% CI [2.53 - 4,91].

CONCLUSION

Survival from TCA is lower than in non-TCA. TCA has different predictors of outcome compared to non-TCA, illustrating the differences regarding the aetiologies of cardiac arrest. Presenting with an initial shockable cardiac rhythm might be associated with a favourable outcome in TCA.

Using Virtual Reality Head-Mounted Displays to Assess Skills in Emergency Medicine: Validity Study

BACKGROUND

Many junior doctors must prepare to manage acutely ill patients in the emergency department. The setting is often stressful, and urgent treatment decisions are needed. Overlooking symptoms and making wrong choices may lead to substantial patient morbidity or death, and it is essential to ensure that junior doctors are competent. Virtual reality (VR) software can provide standardized and unbiased assessment, but solid validity evidence is necessary before implementation.

OBJECTIVE

This study aimed to gather validity evidence for using 360-degree VR videos with integrated multiple-choice questions (MCQs) to assess emergency medicine skills.

METHODS

Five full-scale emergency medicine scenarios were recorded with a 360-degree video camera, and MCQs were integrated into the scenarios to be played in a head-mounted display. We invited 3 groups of medical students with different experience levels to participate: first- to third-year medical students (novice group), last-year medical students without emergency medicine training (intermediate group), and last-year medical students with completed emergency medicine training (experienced group). Each participant's total test score was calculated based on the number of correct MCQ answers (maximum score of 28), and the groups' mean scores were compared. The participants rated their experienced presence in emergency scenarios using the Igroup Presence Questionnaire (IPQ) and their cognitive workload with the National Aeronautics and Space Administration Task Load Index (NASA-TLX).

RESULTS

We included 61 medical students from December 2020 to December 2021. The experienced group had significantly higher mean scores than the intermediate group (23 vs 20; P=.04), and the intermediate group had significantly higher scores than the novice group (20 vs 14; P<.001). The contrasting groups' standard-setting method established a pass-or-fail score of 19 points (68% of the maximum possible score of 28). Interscenario reliability was high, with a Cronbach α of 0.82. The participants experienced the VR scenarios with a high degree of presence with an IPQ score of 5.83 (on a scale from 1-7), and the task was shown to be mentally demanding with a NASA-TLX score of 13.30 (on a scale from 1-21).

CONCLUSIONS

This study provides validity evidence to support using 360-degree VR scenarios to assess emergency medicine skills. The students evaluated the VR experience as mentally demanding with a high degree of presence, suggesting that VR is a promising new technology for emergency medicine skills assessment.

Exploring training needs of newly graduated medical doctors to inform the undergraduate simulation-based curriculum: a national Delphi consensus study

PURPOSE

Mastering technical procedures is a key component in succeeding as a newly graduated medical doctor and is of critical importance to ensure patient safety. The efficacy of simulation-based education has been demonstrated but medical schools have different requirements for undergraduate curricula. We aimed to identify and prioritize the technical procedures needed by newly graduated medical doctors.

METHODS

We conducted a national needs assessment survey using the Delphi technique to gather consensus from key opinion leaders in the field. In the first round, a brainstorm was conducted to identify all potential technical procedures. In the second round, respondents rated the need for simulation-based training of each procedure using the Copenhagen Academy for Medical Education and Simulation Needs Assessment Formula (CAMES-NAF). The third round was a final elimination and prioritization of the procedures.

RESULTS

In total, 107 experts from 21 specialties answered the first round: 123 unique technical procedures were suggested. Response rates were 58% and 64% in the second and the third round, respectively. In the third round, 104 procedures were eliminated based on the consensus criterion, and the remaining 19 procedures were included and prioritized. The top five procedures were: (i) insert peripheral intravenous catheter, (ii) put on personal protection equipment, (iii) perform basic airway maneuvers, (iv) perform basic life support, and (v) perform radial artery puncture.

CONCLUSION

Based on the Delphi process a final list of 19 technical procedures reached expert consensus to be included in the undergraduate curriculum for simulation-based education.

Evaluation of a critical incident management system on mental health in lifeguard organisations: a retrospective study

Background

Lifeguards may face many life-threatening situations during their careers and may be at increased risk of post-traumatic stress disorder (PTSD). Minimal evidence concerning critical incident management systems in lifeguard organisations exists.

Objectives

To develop, implement and evaluate an operational system for critical incident management in lifeguard organisations.

Methods

This retrospective study included data on occupational injury reports from 2013 to 2022 in TrygFonden Surf Lifesaving Denmark. All active lifeguards were invited to evaluate the system and the individual steps using an online questionnaire with three questions rated on a 5-point Likert scale. Primary outcome was a change in the frequency of psychological injury reports after system implementation in 2020. The secondary outcome was the lifeguards' satisfaction with the system.

Results

After implementation, the average annual number of psychological injury reports increased 6.5-fold from 2 (2013-2019) to 13 (2020-2022), without changes to the number of critical incidents attended by the lifeguards. Sixty-six (33.8%) active lifeguards answered the questionnaire and agreed that follow-up after critical incidents was very important (mean score 4.7/5). Satisfaction with steps 1-2 and 3 of critical incident management among involved lifeguards was high (mean score 4.4/5 and 4.6/5, respectively). The system included an operational workflow diagram and incident report template presented in this study.

Conclusions

The operational system for critical incident management may improve early recognition of symptoms for the prevention of PTSD. It may be used as a screening and decision tool for referral to a mental health professional.

Pediatric out-of-hospital cardiac arrest in Denmark

Background

Pediatric out-of-hospital cardiac arrest (POHCA) has received limited attention. All causes of POHCA and outcomes were examined during a 4-year period in a Danish nationwide register and prehospital medical records. The aim was to describe the incidence, reversible causes, and survival rates for POHCA in Denmark.

Methods

This is a registry-based follow-up cohort study. All POHCA for a 4-year period (2016–2019) in Denmark were included. All prehospital medical records for the included subjects were reviewed manually by five independent raters establishing whether a presumed reversible cause could be assigned.

Results

We identified 173 cases within the study period. The median incidence of POHCA in the population below 17 years of age was 4.2 per 100,000 persons at risk. We found a presumed reversible cause in 48.6% of cases, with hypoxia being the predominant cause of POHCA (42.2%). The thirty-day survival was 40%. Variations were seen across age groups, with the lowest survival rate in cases below 1 year of age. Defibrillators were used more frequently among survivors, with 16% of survivors defibrillated bystanders as opposed to 1.9% in non-survivors and 24% by EMS personnel as opposed to 7.8% in non-survivors. The differences in initial rhythm being shockable was 34% for survivors and 16% for non-survivors.

Conclusion

We found pediatric out-of-hospital cardiac arrests was a rare event, with higher incidence and mortality in infants compared to other age groups of children. Use of defibrillators was disproportionally higher among survivors. Hypoxia was the most common presumed cause among all age groups.

Assessment of breathing in cardiac arrest: a randomised controlled trial of three teaching methods among laypersons

Background

The aim of this trial was to compare a video- and a simulation-based teaching method to the conventional lecture-based method, hypothesizing that the video- and simulation-based teaching methods would lead to improved recognition of breathing patterns during cardiac arrest.

Methods

In this Danish, investigator-initiated, stratified, randomised controlled trial, adult laypersons (university students, military conscripts and elderly retirees) participating in European Resuscitation Council Basic Life Support courses were randomised to receive teaching on how to recognise breathing patterns using a lecture- (usual practice), a video-, or a simulation-based teaching method. The primary outcome was recognition of breathing patterns in nine videos of actors simulating normal breathing, no breathing, and agonal breathing (three of each). We analysed outcomes using logistic regression models and present results as odds ratios (ORs) with 95% confidence intervals (CIs) and P-values from likelihood ratio tests.

Results

One hundred fifty-three participants were included in the analyses from February 2, 2018 through May 21, 2019 and recognition of breathing patterns was statistically significantly different between the teaching methods (P = 0.013). Compared to lecture-based teaching (83% correct answers), both video- (90% correct answers; OR 1.77, 95% CI: 1.19–2.64) and simulation-based teaching (88% correct answers; OR 1.48; 95% CI: 1.01–2.17) led to significantly more correct answers. Video-based teaching was not statistically significantly different compared to simulation-based teaching (OR 1.20; 95% CI: 0.78–1.83).

Conclusion

Video- and simulation-based teaching methods led to improved recognition of breathing patterns among laypersons participating in adult Basic Life Support courses compared to the conventional lecture-based teaching method.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00513-4.

Ketamine versus propofol for rapid sequence induction in trauma patients: a retrospective study

BACKGROUND

Rapid Sequence Induction (RSI) is used for emergency tracheal intubation to minimise the risk of pulmonary aspiration of stomach contents. Ketamine and propofol are two commonly used induction agents for RSI in trauma patients. Yet, no consensus exists on the optimal induction agent for RSI in the trauma population. The aim of this study was to compare 30-day mortality in trauma patients after emergency intubation prehospitally or within 30 min after arrival in the trauma centre using either ketamine or propofol for RSI.

METHODS

In this investigator-initiated, retrospective study we included adult trauma patients emergently intubated with ketamine or propofol registered in the local trauma registry at Rigshospitalet, a tertiary university hospital that hosts a level-1 trauma centre. The primary outcome was 30-day mortality. Secondary outcomes included hospital and Intensive Care Unit length of stay as well as duration of mechanical ventilation. We analysed outcomes using multivariable logistic regression models adjusting for age, sex, injury severity score, shock (systolic blood pressure < 90 mmHg) and Glasgow Coma Scale score before intubation and present results as odds ratios (ORs) with 95% confidence intervals.

RESULTS

From January 1st, 2015 through December 31st, 2019 we identified a total of 548 eligible patients. A total of 228 and 320 patients received ketamine and propofol, respectively. The 30-day mortality for patients receiving ketamine and propofol was 20.2% and 22.8% (P = 0.46), respectively. Adjusted OR for 30-day mortality was 0.98 [0.58-1.66], P = 0.93. We found no significant association between type of induction agent and hospital length of stay, Intensive Care Unit length of stay or duration of mechanical ventilation.

CONCLUSIONS

In this study, trauma patients intubated with ketamine did not have a lower 30-day mortality as compared with propofol.

Symptoms presented during emergency telephone calls for patients with spontaneous subarachnoid haemorrhage

Background

A spontaneous subarachnoid haemorrhage (SAH) is one of the most critical neurological emergencies a dispatcher can face in an emergency telephone call. No study has yet investigated which symptoms are presented in emergency telephone calls for these patients. We aimed to identify symptoms indicative of SAH and to determine the sensitivity of these and their association (odds ratio, OR) with SAH.

Methods

This was a nested case–control study based on all telephone calls to the medical dispatch center of Copenhagen Emergency Medical Services in a 4-year time period. Patients with SAH were identified in the Danish National Patient Register; diagnoses were verified by medical record review and their emergency telephone call audio files were extracted. Audio files were replayed, and symptoms extracted in a standardized manner. Audio files of a control group were replayed and assessed as well.

Results

We included 224 SAH patients and 609 controls. Cardiac arrest and persisting unconsciousness were reported in 5.8% and 14.7% of SAH patients, respectively. The highest sensitivity was found for headache (58.9%), nausea/vomiting (46.9%) and neck pain (32.6%). Among conscious SAH patients these symptoms were found to have the strongest association with SAH (OR 27.0, 8.41 and 34.0, respectively). Inability to stand up, speech difficulty, or sweating were reported in 24.6%, 24.2%, and 22.8%. The most frequent combination of symptoms was headache and nausea/vomiting, which was reported in 41.6% of SAH patients. More than 90% of headaches were severe, but headache was not reported in 29.7% of conscious SAH patients. In these, syncope was described by 49.1% and nausea/vomiting by 37.7%.

Conclusion

Headache, nausea/vomiting, and neck pain had the highest sensitivity and strongest association with SAH in emergency telephone calls. Unspecific symptoms such as inability to stand up, speech difficulty or sweating were reported in 1 out of 5 calls. Interestingly, 1 in 3 conscious SAH patients did not report headache.

Trial registration NCT03980613 (www.clinicaltrials.gov).