Sex differences in pre-hospital analgesia and outcomes in patients presenting with acute coronary syndromes

Background

Opioid analgesia remains the mainstay of pain management in acute coronary syndromes (ACS). Significant sex differences persist in ACS presentation, management and outcomes, but the impact of sex-differences on pre-hospital pain management of ACS with opioids is unknown. There is increasing awareness of the importance of pre-hospital factors in ACS, as well as emerging concerns with opioid use impairing the gastrointestinal absorption of oral P2Y12 inhibitors.

Purpose

This study examined if sex-differences in pre-hospital pain scores, opioid administration and clinical outcomes exist in ACS patients.

Methods

Patients presenting with ACS via ambulance (2014–2018) that underwent percutaneous coronary intervention (PCI) were prospectively collected via the Victorian Cardiac Outcomes Registry (VCOR), the Melbourne Interventional Group (MIG), and linked to the Ambulance Victoria database. The primary outcome was 30-day major adverse cardiac events (MACE). Secondary outcomes were descriptive analyses of pre-hospital pain score, intravenous morphine equivalent analgesic dosing, plus predictors of MACE and Thrombolysis In Myocardial Infarction (TIMI) 0–1 flow pre-PCI using logistic regression.

Results

10,547 patients were included (female: 2,775 [26.3%]). Opioids were administered to 1,585 (57%) females and 5,068 (65%) males (p<0.001). Adjusted 30-day MACE was similar between opioid groups in both sexes (female: OR 1.21, CI 0.82–1.79, p=0.34; male: OR 0.89, 0.68–1.16, p=0.40). Median pain score at presentation was 6 (IQR 4,8) for both sexes. Median opioid dose was 2.5 mg (IQR 0,10) in females and 5 mg (IQR 0,10) in males (p<0.001), with similar pain relief achieved. Adjusted rates of TIMI 0–1 pre-PCI were higher in patients administered opioids (female: OR 2.83, CI 2.14–3.56, p<0.001; male: OR 2.95, CI 2.49–3.49, p<0.001).

Conclusions

Female patients undergoing PCI received less opioid analgesia, but no sex-differences in pre-hospital pain scores were seen. Opioid administration was associated with impaired antegrade flow in the culprit artery in both sexes, but not short-term MACE. Randomised trials evaluating the clinical implications of opioid administration in ACS with sex subgroup analyses are needed to guide clinical practice.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Melbourne Interventional GroupVictorian Cardiac Outcomes Registry

Daylight savings time transitions and risk of out-of-hospital cardiac arrest: An interrupted time series analysis

BACKGROUND

Many studies have reported increases in the risk of acute cardiovascular events following daylight savings time (DST) transitions. We sought to investigate the effect of DST transition on the incidence of out-of-hospital cardiac arrest (OHCA).

METHODS

Between January 2000 and December 2020, we performed an interrupted time series analysis of the daily number of OHCA cases of medical aetiology from the Victorian Ambulance Cardiac Arrest Registry. The effect of DST transition on OHCA incidence was estimated using negative binomial models, adjusted for temporal trends, population growth, and public holidays.

RESULTS

A total of 89,409 adult OHCA of medical aetiology were included. Following the spring DST transition (i.e. shorter day), there was an immediate 13% (IRR 1.13, 95% CI: 1.02, 1.25; p = 0.02) increased risk of OHCA on the day of transition (Sunday) and the cumulative risk of OHCA remained higher over the first 2 days (IRR 1.17, 95% CI: 1.02, 1.34; p = 0.03) compared to non-transitional days. Following the autumn DST transition (i.e. longer day), there was a significant lagged effect on the Tuesday with a 12% (IRR 0.88, 95% CI: 0.77, 0.99; p = 0.04) reduced risk of OHCA. The cumulative effect following the autumn DST transition was also significant, with a 30% (IRR 0.70, 95% CI: 0.51, 0.96; p = 0.03) reduction in the incidence of OHCA by the end of the transitional week.

CONCLUSION

We observed both harmful and protective effects from DST transitions on the risk of OHCA. Strategies to reduce this risk in vulnerable populations should be considered.

The Impact of the COVID-19 Pandemic on Demand for Emergency Ambulances in Victoria, Australia

Objective: Relatively little has been reported about the impact of COVID-19 restrictions on emergency ambulance services. We describe the influence of the COVID-19 pandemic on the emergency ambulance system in Victoria, Australia.Methods: We performed an interrupted time series analysis of consecutive calls for ambulance from January 2018 to February 2021, including two waves of COVID-19. The COVID-19 lockdown period included seven months of stay-at-home restrictions (16/03/2020-18/10/2020). Nineteen weeks of post-lockdown data were included (19/10/2020-28/02/2021).Results: In total, 2,356,326 consecutive calls were included. COVID-19 lockdown was associated with an absolute reduction of 64,991 calls (almost 2,100 calls/week). According to time series analysis, lockdown was associated with a 12.6% reduction in weekly calls (IRR = 0.874 [95% CI 0.811, 0.941]), however no change in long-term trend (IRR = 1.000 [95% CI 0.996, 1.003]). During lockdown, the long-term trend of attendances to patients with suspected acute coronary syndromes (ACS, IRR = 1.006 [95% CI 1.004, 1.009]) and mental health-related issues (IRR = 1.005 [95% CI 1.002, 1.008]) increased. After lockdown, the call volume was 5.6% below pre-COVID-19 predictions (IRR = 0.944 [95% CI 0.909, 0.980]), however attendances for suspected ACS were higher than predicted (IRR = 1.069 [95% CI 1.009, 1.132]). Ambulance response times deteriorated, and total case times were longer than prior to the pandemic, driven predominantly by extended hospital transfer times.Conclusion: The COVID-19 pandemic had a dramatic impact on the emergency ambulance system. Despite lower call volumes post-lockdown than predicted, we observed deteriorating ambulance response times, extended case times and hospital delays. The pattern of attendance to patients with suspected ACS potentially highlights the collateral burden of delaying treatment for urgent conditions.

Impact of limited English proficiency on presentation and clinical outcomes of patients undergoing primary percutaneous coronary intervention

AIMS

To evaluate the association of limited English proficiency (LEP) with reperfusion times and outcomes in patients undergoing primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

This cohort study included 5385 patients who underwent PPCI in 2013-2017 and were prospectively enrolled in the Victorian Cardiac Outcomes Registry. Data linkage to government administrative datasets was performed to identify patients' preferred spoken language, socioeconomic status, and ambulance utilization data. Patients who had a preferred spoken language other than English were defined as having LEP. Of the study cohort, 430 patients (8.0%) had LEP. They had longer mean symptom-to-door time (STDT) [164 (95% confidence interval, CI 149-181) vs. 136 (95% CI 132-140) min, P < 0.001] but similar mean door-to-balloon time [79 (95% CI 72-87) vs. 76 (95% CI 74-78) min, P = 0.41]. They also had higher major adverse cardiovascular and cerebrovascular events (MACCE; 13.5% vs. 9.9%; P = 0.02), severe left ventricular dysfunction (11.0% vs. 8.4%, P = 0.02), and heart failure (HF) hospitalizations within 30 days of PPCI (5.1% vs. 2.0%, P < 0.001). On multivariable analysis, LEP did not independently predict 30-day MACCE [odds ratio (OR) 1.16, 95% CI 0.79-1.69; P = 0.45] but was an independent predictor of both prolonged STDT ≥ 120 min (OR 1.25, 95% CI 1.02-1.52; P = 0.03) and 30-day HF hospitalizations (OR 2.01, 95% CI 1.21-3.36; P = 0.008).

CONCLUSION

Patients with LEP undergoing PPCI present later and are more likely to have HF readmissions within 30 days of percutaneous coronary intervention, but with similar short-term MACCE. More effort to provide education in varied languages on early presentation in STEMI is required.

Pre-hospital heparin use for ST-elevation myocardial infarction is safe and improves angiographic outcomes

AIMS

This study aims to evaluate if pre-hospital heparin administration by paramedics is safe and improves clinical outcomes.

METHODS AND RESULTS

Using the multicentre Victorian Cardiac Outcomes Registry, linked with state-wide ambulance records, we identified consecutive patients undergoing primary percutaneous coronary intervention for STEMI between January 2014 and December 2018. Information on thrombolysis in myocardial infarction (TIMI) flow at angiography was available in a subset of cases. Patients receiving pre-hospital heparin were compared to those who did not receive heparin. Findings at coronary angiography and 30-day clinical outcomes were compared between groups. Propensity-score matching was performed for risk adjustment. We identified a total of 4720 patients. Of these, 1967 patients had TIMI flow data available. Propensity-score matching in the entire cohort yielded 1373 matched pairs. In the matched cohort, there was no observed difference in 30-day mortality (no-heparin 3.5% vs. heparin 3.0%, P = 0.25), MACCE (no-heparin 7% vs. heparin 6.2%, P = 0.44), and major bleeding (no-heparin 1.9% vs. heparin 1.4%, P = 0.64) between groups. Propensity-score analysis amongst those with TIMI data produced 552 matched pairs. The proportion of cases with TIMI 0 or 1 flow in the infarct-related artery (IRA) was lower among those receiving pre-hospital heparin (66% vs. 76%, P < 0.001) compared to those who did not.

CONCLUSION 

In this multicentre, propensity-score matched study, the use of pre-hospital heparin by paramedics was safe and is associated with fewer occluded IRAs in patients presenting with STEMI.

Sex Differences in Prehospital Delays in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Background

Women with ST‐segment–elevation myocardial infarction experience delays in reperfusion compared with men with little data on each time component from symptom onset to reperfusion. This study analyzed sex discrepancies in patient delays, prehospital system delays, and hospital delays.

Methods and Results

Consecutive patients with ST‐segment–elevation myocardial infarction treated with percutaneous coronary intervention across 30 hospitals in the Victorian Cardiac Outcomes Registry (2013–2018) were analyzed. Data from the Ambulance Victoria Data warehouse were used to perform linkage to the Victorian Cardiac Outcomes Registry for all patients transported via emergency medical services (EMS). The primary end point was EMS call‐to‐door time (prehospital system delay). Secondary end points included symptom‐to‐EMS call time (patient delay), door‐to‐device time (hospital delay), 30‐day mortality, major adverse cardiovascular events, and major bleeding. End points were analyzed according to sex and adjusted for age, comorbidities, cardiogenic shock, cardiac arrest, and symptom onset time. A total of 6330 (21% women) patients with ST‐segment–elevation myocardial infarction were transported by EMS. Compared with men, women had longer adjusted geometric mean symptom‐to‐EMS call times (47.0 versus 44.0 minutes; P<0.001), EMS call‐to‐door times (58.1 versus 55.7 minutes; P<0.001), and door‐to‐device times (58.5 versus 54.9 minutes; P=0.006). Compared with men, women had higher 30‐day mortality (odds ratio [OR], 1.38; 95% CI, 1.06–1.79; P=0.02) and major bleeding (OR, 1.54; 95% CI, 1.08–2.20; P=0.02).

Conclusions

Female patients with ST‐segment–elevation myocardial infarction experienced excess delays in patient delays, prehospital system delays, and hospital delays, even after adjustment for confounders. Prehospital system and hospital delays resulted in an adjusted excess delay of 10 minutes compared with men.

Endotracheal Tube Intracuff Pressure Changes in Patients Transported by a Helicopter Emergency Medical Service: A Prospective Observational Study

OBJECTIVE

The pressure within an endotracheal tube cuff is of particular importance in helicopter emergency medical services (HEMS) transport because the unpressurized cabin is subjected to decreases in atmospheric pressure. This can cause the cuff to overinflate and may be associated with clinical complications. We sought to evaluate endotracheal tube cuff pressure changes among intubated patients during HEMS transport.

METHODS

A prospective observational study was performed including adult patients who were intubated and transported by helicopter between April 2017 and October 2018. Cuff pressures were measured before, during, and after HEMS transport with a commercial manometer.

RESULTS

A total of 208 patients were included. The median maximum flight altitude was 3,000 (interquartile range [IQR], 2,000-5,000) ft. The median initial cuff pressure before takeoff was 35 (IQR, 24-50) cm H₂O, which increased to 50 (IQR, 35-70) cm H₂O at maximum altitude. A total of 169 (81.3%) patients had a cuff pressure > 30 cm H₂O at maximum altitude. There was a moderate correlation between altitude and cuff pressure (r = 0.532, P < .001).

CONCLUSIONS

Cuff pressure increased during HEMS transport, demonstrating the need for routine cuff pressure monitoring during flight. Further research is required to determine if exposure to transient increases in cuff pressure for short durations is clinically significant.

An open-label, non-inferiority randomized controlled trial of lidocAine Versus Opioids In MyocarDial Infarction study (AVOID-2 study) methods paper

Background There is increasing evidence that opioids interfere with the oral bioavailability of P2Y₁₂ inhibitors leading to delayed onset of antiplatelet effects. Several strategies have been proposed to mitigate this interaction including utilizing alternative analgesic agents in the management of ischemic chest pain. Methods The lidocAine Versus Opioids In MyocarDial Infarction (AVOID-2) study is a phase II, pre-hospital, open-label, non-inferiority, randomized controlled trial conducted by Ambulance Victoria and Monash University in metropolitan Melbourne, Victoria, Australia. The purpose of the study is to compare the analgesic effect (reduction in pain by arrival to hospital) and safety (e.g. adverse drug reactions) (co-primary endpoints) of intravenous lidocaine versus intravenous fentanyl in 300 adult patients attended by ambulance with suspected ST-elevation myocardial infarction (STEMI). Secondary endpoints and a cardiac magnetic resonance imaging (MRI) sub-study will also compare infarct size between these two groups. Conclusions The evaluation of alternative analgesic agents in the management of acute coronary syndromes is urgently needed to manage the opioid-P2Y₁₂ inhibitor interaction. The results of this trial will have significant implications on the emergency management of acute coronary syndromes internationally.

Pre-Hospital Factors Influencing the Provision of Acute Care for Patients with Stroke: Preliminary Findings from A State-Wide Data Linkage Study

IntroductionImprovement in access to reperfusion therapy and reductions in treatment delays requires coordination of multiple systems and services including a well-organised and streamlined pre-hospital care system. Objectives and ApproachOur objective is to examine pre-hospital and hospital factors that influence long-term outcomes in patients with stroke. We linked and merged patient-level data from the Australian Stroke Clinical Registry (AuSCR) to Ambulance Victoria (AV), hospital administrative datasets (Victorian Admitted Episodes Data; VAED) and emergency department data (Victorian Emergency Minimum Dataset; VEMD) using probabilistic, iterative methods. Logistic regression models were used to determine clinical factors associated with access to evidence-based treatments. Results7,373 episodes in the AuSCR were available for linkage, of which 4,569 (62%) were matched with AV records (58% male, median age 72 years). Of these 4,569 matched records, 4,159 (58% male, median age 73 years) had a record in the VAED or VEMD. Stroke or transient ischaemic attack was suspected for 68% of patients by paramedics based on the AV data. Highest transport priority was used for 64% of patients. Patients suspected of stroke by paramedics were more likely to be treated in stroke unit (unadjusted odds ratio, 1.72; 1.47, 2.01) and more likely to receive thrombolysis if ischaemic stroke (unadjusted odd ratio: 4.64, 3.47, 6.20). Conclusion/ImplicationsLinkage of these administrative data with the AuSCR provide the opportunity to interrogate a range of questions to inform policy and practice of acute stroke care. Future analyses will investigate patient (such as comorbidities), clinical and system factors that influence provision of evidence-based care for patients with stroke and whether these influence outcomes at 6 months after stroke.

Drivers of Increasing Emergency Ambulance Demand

Objectives: Although the factors driving emergency department demand have been extensively investigated, a comparatively minimal amount is known about the factors that are driving an increase in emergency ambulance demand. Methods: We conducted a retrospective observational study of consecutive cases attended by Ambulance Victoria in Melbourne, Australia from 2008 to 2015. Incidence rates were calculated, and adjusted time series regression analyses were performed to assess the driving factors of ambulance demand. Results: A total of 2,443,952 consecutive cases were included. Demand grew by 29.2% over the 8-year period. The age-specific incidence increased significantly over time for patients aged < 60 years, but not for patients aged ≥ 60 years. After adjustment for seasonality and population growth, demand increased by 1.4% per annum (incident rate ratio [IRR] = 1.014 [1.011-1.017]). The largest annual growth in demand was observed in patients with a history of mental health issues (IRR = 1.058 [1.054-1.062]), alcohol/drug abuse (IRR = 1.061 [1.056-1.066]), or a Charlson Comorbidity Index [CCI] score ≥ 4 (IRR = 1.045 [1.039-1.051]). Cases involving patients of relative socio-economic/educational disadvantage, younger age, or with no preexisting health conditions according to the CCI also grew faster than the overall patient population. Cases requiring transport to hospital increased by 1.2% annually (IRR = 1.012 [1.009-1.016]), although patients not requiring medical intervention from paramedics increased by 6.7% annually (IRR = 1.067 [1.063-1.072]). Conclusions: Increases in ambulance demand exceeded population growth. Emergency ambulances were increasingly utilized for transport of patients who did not require medical intervention from paramedics. Identifying the characteristics of patients driving ambulance demand will enable targeted demand management strategies.

Ambulances are for emergencies: shifting behaviour through a research-informed behaviour change campaign

Background

A major review of Victoria’s ambulance services identified the need to improve public awareness of the role of ambulances as an emergency service. A communications campaign was developed to address this challenge. This research paper expands on an initial evaluation of the campaign by focusing on the long-term behavioural outcomes.

Methods

The behavioural evaluation involved two types of data collection – administrative data (routine collection from various health services) and survey data (cross-sectional community-wide surveys to measure behavioural intentions).

Results

Behavioural intentions for accessing two of the targeted non-emergency services increased after the second phase of the campaign commenced. There was also a significant change in the slope of call trends for emergency ambulances. This decrease is also likely attributed to the second phase of the campaign as significant level effects were identified 3 and 9 months after it commenced.

Conclusions

A long-term campaign developed through evidence review, stakeholder consultation and behavioural theory was successful in reducing the number of daily calls requesting an emergency ambulance in Victoria and in increasing intentions to use alternative services. This research highlights the importance of collaborative intervention design along with the importance of implementing a robust monitoring and evaluation framework.

OP7 Palliative care in paramedic practice: a retrospective cohort study

Introduction

Paramedics may be involved in the care of patients experiencing a health crisis associated with palliative care. However, little is known about the paramedic’s role in the care of these patients. This study therefore aimed to describe the incidence and nature of cases attended by paramedics, the treatment provided, and the transport destination if transported, where the reason for attendance was associated with a history of palliative care.

Methods

This retrospective cohort study included all adult patients (aged > 17 years) attended by paramedics in the Australian state of Victoria between 1 July 2015 and 30 June 2016 where terms associated with palliative care, dying or end of life were recorded in the patient care record. Secondary transfers were excluded. Descriptive statistics were used to analyse the sample. Categorical data are presented as frequencies and proportions, with comparisons made using the χ2 test.

Results

4,348 cases met inclusion criteria. Most patients were aged between 61–80 years (47.9%). The most common assessments recorded by paramedics were ‘respiratory’ (20.1%), ‘pain’ (15.8%), and ‘deceased’ (7.9%). 54.0% (n=2,346) received treatment from the paramedics, and 74.4% (n=3,237) were transported, with the most common destination a hospital (99.5%, n=3,221). Of those with pain as the primary impression, 359 (53.9%) received an analgesic. Nausea and/or vomiting was documented in 15.6% (n=680) of cases attended. Antiemetics administered in these cases included metoclopramide (n=71, 10.4%), prochlorperazine (n=21, 3.1%), and ondansetron (n=9, 1.3%). Resuscitation was attempted in 98 (29.1%) of the 337 cases coded as cardiac arrest. Among non-transported cases, there were 105 (9.6%) cases where paramedics re-attended the patient within 24 hours of the previous attendance.

Discussion and conclusion

Paramedics may become involved in the care of patients receiving palliative care due to exacerbation of symptoms or a new health emergency. As such, the paramedic has a key role in managing symptoms or liaising with other members of the patient’s palliative care team to provide appropriate care. The results should inform integrated systems of care that involve ambulance services in the planning and delivery of community-based palliative care.

Trends in survival from out-of-hospital cardiac arrests defibrillated by paramedics, first responders and bystanders

BACKGROUND

Although survival from out-of-hospital cardiac arrest (OHCA) is increasing, little is known about the long-term trends in survival for patients defibrillated by first responders and bystanders.

METHODS

Between 2000 and 2017, we included adult non-traumatic OHCA with an initial shockable rhythm from the Victorian Ambulance Cardiac Arrest Registry. Adjusted logistic regression analyses were used to assess trends in survival to hospital discharge according to whether the patient was initially shocked by paramedics, first responders or bystanders.

RESULTS

Of the 10,451 initial shockable arrests, 796 (7.6%) and 526 (5.0%) were initially shocked by first responders and bystanders, respectively. Between 2000-02 and 2015-17, the proportion of cases initially shocked by first responders and bystanders increased from 3.8% to 8.2% and from 2.0% to 11.2%, respectively. Over the same period, survival to hospital discharge increased from 11.6% to 28.8% for cases initially shocked by paramedics, from 10.5% to 37.8% for cases initially shocked by first responders, and from 6.7% to 55.5% for cases initially shocked by bystanders (p trend <0.001 for all). In the adjusted analyses, patients initially shocked by first responders (AOR 1.40, 95% CI: 1.18, 1.67; p < 0.001) and bystanders (AOR 2.11, 95% CI: 1.72, 2.59; p < 0.001) were more likely to survive to hospital discharge than those initially shocked by paramedics. The odds of survival increased year-on-year by 8.1% for patients shocked by paramedics (p < 0.001), 6.1% for patients shocked by first responders (p = 0.004), and 11.8% for patients shocked by bystanders (p < 0.001).

CONCLUSION

OHCA patients initially defibrillated by bystanders yielded the largest improvements in survival over time.

Palliative care in paramedic practice: A retrospective cohort study

BACKGROUND

Paramedics may be involved in the care of patients experiencing a health crisis associated with palliative care. However, little is known about the paramedic's role in the care of these patients.

AIM

To describe the incidence and nature of cases attended by paramedics and the care provided where the reason for attendance was associated with a history of palliative care.

DESIGN

This is a retrospective cohort study.

SETTING/PARTICIPANTS

Adult patients (aged >17 years) attended by paramedics in the Australian state of Victoria between 1 July 2015 and 30 June 2016 where terms associated with palliative care or end of life were recorded in the patient care record. Secondary transfers including inter-hospital transport cases were excluded.

RESULTS

A total of 4348 cases met inclusion criteria. Median age was 74 years (interquartile range 64-83). The most common paramedic assessments were 'respiratory' (20.1%), 'pain' (15.8%) and 'deceased' (7.9%); 74.4% ( n = 3237) were transported, with the most common destination being a hospital (99.5%, n = 3221). Of those with pain as the primary impression, 359 (53.9%) received an analgesic, morphine, fentanyl or methoxyflurane, and 356 (99.2%) were transported following analgesic administration. Resuscitation was attempted in 98 (29.1%) of the 337 cases coded as cardiac arrest. Among non-transported cases, there were 105 (9.6%) cases where paramedics re-attended the patient within 24 h of the previous attendance.

CONCLUSION

Paramedics have a significant role in caring for patients receiving palliative care. These results should inform the design of integrated systems of care that involve ambulance services in the planning and delivery of community-based palliative care.

Can pre-hospital administration reduce time to initial antibiotic therapy in septic patients?

OBJECTIVE

To quantify the potential time saved with pre-hospital antibiotic therapy in sepsis.

METHODS

Study data for adult patients transported by Ambulance Victoria (AV), and enrolled into the Australasian Resuscitation In Sepsis Evaluation (ARISE), were linked with pre-hospital electronic records.

RESULTS

An AV record was identified for 240 of 341 ARISE patients. The pre-hospital case notes referred to potential infection in 165 patients. The median time to first antibiotic administration from loading the patient into the ambulance was 107 (74-160) min.

CONCLUSIONS

ARISE patients in Victoria were frequently identified pre-hospital. An opportunity exists to study the feasibility of pre-hospital antibiotic therapy.