Association between direct transport to a cardiac arrest centre and survival following out-of-hospital cardiac arrest: A propensity-matched Aotearoa New Zealand study

Background and Objectives

Direct transport to a cardiac arrest centre following out-of-hospital cardiac arrest may be associated with higher survival. However, there is limited evidence available to support this within the New Zealand context. This study used a propensity score-matched cohort to investigate whether direct transport to a cardiac arrest centre improved survival in New Zealand.

Methods

A retrospective cohort study was conducted using the Aotearoa New Zealand Paramedic Care Collection (ANZPaCC) database for adults treated for out-of-hospital cardiac arrest of presumed cardiac aetiology between 1 July 2018 to 30 June 2023. Propensity score-matched analysis was used to investigate survival at 30-days post-event according to the receiving hospital being a cardiac arrest centre versus a non-cardiac arrest centre.

Results

There were 2,297 OHCA patients included. Propensity matching resulted in 554 matched pairs (n = 1108). Thirty-day survival in propensity score-matched patients transported directly to a cardiac arrest centre (56%) versus a non-cardiac arrest centre (45%) was not significantly different (adjusted Odds Ratio 0.78 95%CI 0.54, 1.13, p = 0.19). Shockable presenting rhythm, bystander CPR, and presence of STEMI were associated with a higher odds of 30 day survival (p < 0.05). Māori or Pacific Peoples ethnicity and older age were associated with lower survival (p < 0.05).

Conclusions

This study found no statistically significant difference in outcomes for OHCA patients transferred to a cardiac arrest compared to a non-cardiac arrest centre. However, the odds ratio of 0.78, equivalent to a 22% decrease in 30-day mortality, is consistent with benefit associated with management by a cardiac arrest centre. Further research in larger cohorts with detailed information on known outcome predictors, or large randomised clinical trials are needed.

Review article: Emergency medical services transfer of severe traumatic brain injured patients to a neuroscience centre: A systematic review

Patients with severe traumatic brain injuries require urgent medical attention at a hospital. We evaluated whether transporting adult patients with a severe traumatic brain injury (TBI) to a Neuroscience Centre is associated with reduced mortality. We reviewed studies published between 2010 and 2023 on severe TBI in adults (>18 years) using Medline, CINAHL, Google Scholar and Cochrane databases. We focused on mortality rates and the impact of transferring patients to a Neuroscience Centre, delays to neurosurgery and EMS triage accuracy. This review analysed seven studies consisting of 53 365 patients. When patients were directly transported to a Neuroscience Centre, no improvement in survivability was demonstrated. Subsequently, transferring patients from a local hospital to a Neuroscience Centre was significantly associated with reduced mortality in one study (adjusted odds ratio: 0.79, 95% confidence interval: 0.64-0.96), and 24-h (relative risk [RR]: 0.31, 0.11-0.83) and 30-day (RR: 0.66, 0.46-0.96) mortality in another. Patients directly transported to a Neuroscience Centre were more unwell than those taken to a local hospital. Subsequent transfers increased time to CT scanning and neurosurgery in several studies, although these were not statistically significant. Additionally, EMS could accurately triage. None of the included studies demonstrated statistically significant findings indicating that direct transportation to a Neuroscience Centre increased survivability for patients with severe traumatic brain injuries. Subsequent transfers from a non-Neuroscience Centre to a Neuroscience Centre reduced mortality rates at 24 h and 30 days. Further research is required to understand the differences between direct transport and subsequent transfers to Neuroscience Centres.

Analysis of skin condition emergency department outcomes via the free Healthline service from Whakarongorau Aotearoa

The aim of this research is to gain a deeper understanding of the ethnic and socio-demographic differences in the utilisation of the national 24/7 Healthline service in relation to skin condition calls and their outcomes. Healthline is one of the 39 free telehealth services that Whakarongorau Aotearoa | New Zealand Telehealth Services provides to New Zealanders. This is a retrospective observational study analysing Healthline data over a 4-year period: January 2019 through to December 2022. A total of 61,876 skin condition calls were analysed including demographics of service users: age group, ethnicity, area of residence and call outcome. Higher acuity skin condition calls resulting in an outcome of a recommendation for emergency department (ED) care accounted for 5.3% (n=3,294) of calls. This research found that Māori were over-represented in this ED recommendation data over four years (942 ED outcomes; 28.6%), and Pasifika were under-represented (203 ED outcomes; 5.9%). Wairarapa and West Coast were found to have the highest number of ED outcomes per capita. Our results support the theory that severe skin conditions positively correlate with smaller district populations and increased deprivation in access to services. This study highlights the potential that telehealth services have to help reduce the inequity of access to care.

A study protocol for a cluster-randomised controlled trial of smartphone-activated first responders with ultraportable defibrillators in out-of-hospital cardiac arrest: The First Responder Shock Trial (FIRST)

Objective

To describe the First Responder Shock Trial (FIRST), which aims to determine whether equipping frequently responding, smartphone-activated (GoodSAM) first responders with an ultraportable AED can increase 30-day survival rates in OHCA.

Methods

The FIRST trial is an investigator-initiated, bi-national (Victoria, Australia and New Zealand), registry-nested cluster-randomised controlled trial where the unit of randomisation is the smartphone-activated (GoodSAM) first responder. High-frequency GoodSAM responders are randomised 1:1 to receive an ultraportable, single-use AED or standard alert procedures using the GoodSAM app.The primary outcome is survival to 30 days. The secondary outcome measures (shockable rhythm, return of spontaneous circulation, event survival, and time to first shock delivery) are routinely collected by OHCA registries in both regions. The trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) (Registration: ACTRN12622000448741) on 22 March 2022.

Results

The trial started in November 2022 and the last patient is expected to be enrolled in November 2024. We aim to detect a 7% increase in the proportion of 30-day survivors, from 9% in patients attended by control responders to 16% in patients attended by responders randomised to the ultraportable AED intervention arm. With 80% power, an alpha of 0.05, a cluster size of 1.5 and a coefficient of variation for cluster sizes of 1, the sample size required to detect this difference is 714 (357 per arm).

Conclusion

The FIRST study will increase our understanding of the potential role of portable AED use by smartphone-activated community responders and their impact on survival outcomes.

Out-of-Hospital emergency airway management practices: A nationwide observational study from Aotearoa New Zealand

Background and Objectives

Airway management is crucial for emergency care in critically ill patients outside the hospital setting. An Airway Registry is useful in providing essential information for quality improvement purposes. Therefore, this study aimed to develop an out-of-hospital airway registry and describe airway management practices in Aotearoa New Zealand (AoNZ).

Methods

Data from the Aotearoa New Zealand Paramedic Care Collection (ANZPaCC) database were used in a retrospective cohort study covering July 2020 to June 2021. All patients receiving airway interventions were included. An airway intervention was defined as one or more of the following: non-drug assisted endotracheal intubation (NDA-ETI), drug-assisted endotracheal intubation (DA-ETI; where a combination of paralytic agent and sedative were used to aid in intubation), laryngeal mask airway (LMA), oropharyngeal airway (OPA), nasopharyngeal airway (NPA), surgical airway (cricothyroidotomy), suction, jaw thrust. Descriptive statistics were analysed using Chi-Square and logistic regression modelling investigated the relationship between advanced airway success and patient characteristics.

Results

The study included 4,529 patients who underwent 7,779 airway interventions. Basic airway interventions were used most frequently: OPA (45.1%), NPA (29.3%), LMA (28.9%), suction (19.9%) and jaw thrust (17.6%). Advanced airway interventions were used less frequently: NDA-ETI (19.8%), DA-ETI (8.7%), and surgical airways (0.2%). The success rate for ETI (including both NDA-ETI and DA-ETI) was 89.4%, with NDA-ETI success at 85.8% and DA-ETI success at 97.7%. ETI first-pass success rates were significantly lower for males (aOR 0.65, 95%CI 0.48-0.87, p < 0.001) and higher for non-cardiac arrest injury patients (aOR 2.94, 95%CI 1.43-6.00, p < 0.001). In this cohort receiving airway interventions the 1-day mortality rate was 41.1%, demonstrating that a high proportion of these patients were severely clinically compromised.

Conclusions

Out-of-hospital airway management practices and success rates in AoNZ are comparable to those elsewhere. This research has determined the variables to be used as the AoNZ Paramedic Airway Registry ongoing and has demonstrated baseline outcomes in airway management for ongoing quality improvement using this registry.

Predictive value of the New Zealand Early Warning Score for early mortality in low-acuity patients discharged at scene by paramedics: an observational study

OBJECTIVES

The utility of New Zealand Early Warning Score (NZEWS) for prediction of adversity in low-acuity patients discharged at scene by paramedics has not been investigated. The objective of this study was to evaluate the association between the NZEWS risk-assessment tool and adverse outcomes of early mortality or ambulance reattendance within 48 hours in low-acuity, prehospital patients not transported by ambulance.

DESIGN

A retrospective cohort study.

SETTING

Prehospital emergency medical service provided by St John New Zealand over a 2-year period (1 July 2016 through 30 June 2018).

PARTICIPANTS

83 171 low-acuity, adult patients who were attended by an ambulance and discharged at scene. Of these, 41 406 had sufficient recorded data to calculate an NZEWS.

PRIMARY AND SECONDARY OUTCOMES AND MEASURES

Binary logistic regression modelling was used to investigate the association between the NZEWS and adverse outcomes of reattendance within 48 hours, mortality within 2 days, mortality within 7 days and mortality within 30 days.

RESULTS

An NZEWS greater than 0 was significantly associated with all adverse outcomes studied (p<0.01), compared with the reference group (NZEWS=0). There was a startling correlation between 2-day, 7-day and 30-day mortality and higher early warning scores; the odds of 2-day mortality in patients with an early warning score>10 was 70 times that of those scoring 0 (adjusted OR 70.64, 95% CI: 30.73 to 162.36). The best predictability for adverse outcome was observed for 2-day and 7-day mortality, with moderate area under the receiver operating characteristic curve scores of 0.78 (95% CI: 0.73 to 0.82) and 0.74 (95% CI: 0.71 to 0.77), respectively.

CONCLUSIONS

Adverse outcomes in low-acuity non-transported patients show a significant association with risk prediction by the NZEWS. There was a very high association between large early warning scores and 2-day mortality in this patient group. These findings suggest that NZEWS has significant utility for decision support and improving safety when determining the appropriateness of discharging low-acuity patients at the scene.

Positive association between ambulance double-crewing and OHCA outcomes: A New Zealand observational study

Background and objectives

New Zealand emergency medical service (EMS) crewing configurations generally place one (single) or two (double) crew on each responding ambulance unit. Recent studies demonstrated that double-crewing was associated with improved survival from out-of-hospital cardiac arrest (OHCA), therefore single-crewed ambulances have been phased out. We aimed to determine the association between this crewing policy change and OHCA outcomes in New Zealand.

Methods

This is a retrospective observational study using data from the St John OHCA Registry on patients treated during two different time periods: the Pre-Period (1 October 2013-30 June 2015), when single-crewed ambulances were in use by EMS, and the Post-Period (1 July 2016-30 June 2018) when single-crewed ambulances were being phased out. Geographic areas identified as having low levels of double crewing during the Pre-Period were selected for investigation. The outcome of survival to thirty-days post-OHCA was investigated using logistic regression analysis.

Results

The proportion of double-crewed ambulances arriving at OHCA events increased in the Post-Period (81.8%) compared to the Pre-Period (67.5%) (p ≤ 0.001). Response times decreased by two minutes (Pre-Period: median 8 min, IQR [6-11], Post-Period: median 6 min, IQR [4-9]; p ≤ 0.001). Thirty-day survival was significantly improved in the Post-Period (OR 1.63, 95%CI (1.04-2.55), p = 0.03).

Conclusions

An association between improved OHCA survival following increased responses by double-crewed ambulances was demonstrated. This study suggests that improvements in resourcing are associated with improved OHCA outcomes.

Regression Equations for Weight Estimation in Paediatric Resuscitation

BACKGROUND

Weight estimation is critical in paediatric resuscitation, as stopping to weigh a child could influence their survival. Weight estimation methods used in New Zealand (NZ) are not accurate for the population, increasing the complexity of prescribing medication and selecting equipment.

AIM

Develop regression equations (RE) to predict the weight of NZ children based on height, sex, age and ethnicity to be deployed in a mobile application (Weight Estimation Without Waiting).

METHODS

The RE was derived from retrospective regression modelling of a large existing dataset. Data were presented using descriptive statistics and calculation of means, limits of agreement and the proportion of weight estimates within a percentage of actual weight.

CONCLUSION

The RE developed in this study outperformed existing age-based weight estimation methods while providing a method to ensure that weight estimation techniques evolve with NZ children.

Factors Associated with Emergency Medical Service Reattendance in Low Acuity Patients Not Transported by Ambulance

Background: The decision for emergency medical services (EMS) personnel not to transport a patient is challenging: there is a risk of subsequent deterioration but transportation of all patients to hospital would overburden emergency departments. The aim of this large-scale EMS study was to identify factors associated with an increased likelihood of ambulance reattendance within 48 hours in low acuity patients who were not transported by ambulance.Methods: We conducted a 2-year retrospective cohort study using data from the St John New Zealand EMS between 1 July 2016 and 30 June 2018 to investigate demographic and clinical associations with ambulance reattendance.Results: In total, 83,171 low acuity patients not transported by ambulance were included, of whom 4,512 (5.4%) had an EMS ambulance reattend within 48 hours. There were significant associations between EMS reattendance and patient age, sex, ethnicity, deprivation, and event location. Patients aged 60-74 years old had the highest likelihood of ambulance recall (OR 2.87, 95% CI: 2.51-3.28). Males were more likely to have an EMS ambulance reattend within 48 hours (OR 1.17, 95% CI: 1.09-1.25). Māori and Pacific Peoples had a similar likelihood of EMS recall to European/Others; however, the Asian cohort showed a reduced likelihood of reattendance (OR 0.76, 95% CI: 0.62-0.93).There were significant associations between EMS reattendance and non-transport reason, time spent on scene, event type, clinical acuity level (status), and pain score. Shorter (<30 minutes) on scene times were associated with a decreased likelihood of ambulance reattendance, whereas longer scene times (>45 minutes) were associated with an increased likelihood. Medical events were more likely to require reattendance than accident-related events (OR 1.22, 95% CI: 1.13-1.32). Non-transported patients with a severe pain score (7-10/10) were at increased likelihood of requiring reattendance (OR 1.60, 95% CI: 1.33-1.92).Discussion: The overall low rate of EMS reattendance is encouraging. Further research is needed into the clinical presentation of patients requiring ambulance reattendance within 48 hours to determine if there are early warning signs indicative of subsequent deterioration.

Ethnic disparities in the incidence and outcome from out-of-hospital cardiac arrest: A New Zealand observational study

BACKGROUND

New Zealand (NZ) has an ethnically diverse population. International studies have demonstrated significant differences in health equity by ethnicity; however, there is limited evidence in the context of out-of-hospital cardiac arrest in NZ. We investigated whether heath disparities in incidence and outcome of out-of-hospital cardiac arrest exist between NZ ethnic groups.

METHOD

A retrospective observational study was conducted using NZ cardiac arrest registry data for a 2-year period. Ethnic cohorts investigated were the indigenous Māori population, Pacific Peoples and European/Others. Incidence rates, population characteristics and outcomes (Return of Spontaneous Circulation sustained to hospital handover and thirty-day survival) were compared.

RESULTS

Age-adjusted incidence rates per 100,000 person-years were higher in Māori (144.4) and Pacific Peoples (113.5) compared to European/Others (93.8). Return of spontaneous circulation sustained to hospital handover was significantly lower in Māori (adjusted OR 0.74, 95% CI 0.64-0.87, p < 0.001). Survival to thirty-days was lower for both Māori (adjusted OR 0.61, 95% CI 0.48-0.78, p < 0.001) and Pacific Peoples (adjusted OR 0.52, 95% CI 0.37-0.72, p < 0.001). A higher proportion of events occurred in all age groups below 65 years old in Māori and Pacific Peoples (p < 0.001), and a higher proportion of events occurred among women in Māori and Pacific Peoples (p < 0.001).

CONCLUSIONS

There are significant differences in health equity by ethnicity. Both Māori and Pacific Peoples have higher incidence of out-of-hospital cardiac arrest and at a younger age. Māori and Pacific Peoples have lower rates of survival to thirty-days. Our results provide impetus for targeted health strategies for at-risk ethnic populations.

Gender and survival from out-of-hospital cardiac arrest: a New Zealand registry study

Objective

To determine the relationships between survival from all-cause out-of-hospital cardiac arrest (OHCA) and gender in New Zealand.

Methods

A retrospective observational study was conducted using data compliant with the Utstein guidelines from the St John New Zealand OHCA Registry for adult patients who were treated for an OHCA between 1 October 2013 and 30 September 2015. Univariate logistic regression was used to investigate factors associated with return of spontaneous circulation sustained to handover at hospital and survival to 30 days. Multivariate logistic regression models were used to investigate outcome differences in survival according to gender at 30 days postevent.

Results

Women survived to hospital handover in 29% of cases, which was not significantly different from men (31%). When adjusted for age, location, aetiology, initial rhythm and witnessed status, there was no significant difference in 30-day survival between men (16%) and women (13%) (adjusted OR 1.22, 95% CI (0.96 to 1.55), p=0.11).

Conclusion

No statistical differences were found in 30-day survival between genders when adjustments for unfavourable Utstein variables were accounted for.

Accuracy of working diagnosis by paramedics for patients presenting with dyspnoea

OBJECTIVE

The present study aims to determine the agreement between paramedic and ED or hospital working diagnosis in dyspnoeic patients.

METHODS

Non-consecutive written patient report forms were retrospectively audited for patients suffering from dyspnoea, who were transported to a tertiary hospital ED by ambulance paramedics. Accuracy of the paramedic working diagnosis was assessed by comparing agreement with either the primary or secondary ED diagnoses or hospital discharge diagnosis.

RESULTS

The study cohort was 293 patients. Exact agreement between paramedic versus ED or hospital diagnosis was 64%, 95% CI 58-69, k = 0.58, 95% CI 0.52-0.64. Only 226 (77%) had a 'clearly documented' paramedic diagnosis. Among these, agreement with either ED or hospital diagnosis was 79%, and there was a trend towards more agreement as paramedic level of practice increased (74%, 78% and 87% for Basic, Intermediate and ALS paramedics, respectively, P = 0.07). Conversely, ALS paramedics were less likely to document a working diagnosis (30/98, 31%) compared with Intermediate (22/102, 23%) and BLS paramedics (15/93, 16%), P = 0.008. Diagnostic agreement varied according to medical condition, from anaphylaxis (100%) and asthma (86%) to acute pulmonary oedema (46%).

CONCLUSIONS

There was moderate agreement between paramedic and ED or hospital diagnosis. The number of cases with no clearly documented working diagnosis suggested that a singular working diagnosis may not always serve the complexity of presentation of some dyspnoea patients: more open descriptors such as 'mixed disease' or 'atypical features' should be encouraged.

Quality improvement study of day surgery for tonsillectomy and adenoidectomy patients

Ongoing efforts to contain costs in health care have had an impact on the delivery of care in the ambulatory setting. Many patients previously admitted to the hospital for an overnight stay are now discharged home within hours of surgery. In response to concerns raised by nursing staff about same-day discharge of patients undergoing tonsillectomy and adenoidectomy (T&A), a quality improvement (QI) study was conducted. Data from more than 150 families over a 2-year period were collected, using the clinical indicator of safe discharge. The data were obtained during the patient's recovery room stay, the first post-operative day, and 2 weeks after surgery. Findings suggested that some of the teaching done by nurses was useful and some needed revision to meet patients' needs. Changes regarding pain management, fluid management, and post-operative bleeding were addressed.

Survey of the implementation of workplace alcohol and smoking policies among employers in Fife

A survey of major employers in Fife shows that at present 33% of respondents have implemented written alcohol policies, while 40% have implemented written smoking policies. A total of 19% have both alcohol and smoking policies in place. The initiative for policy development appears to have arisen mainly from management, but trade unions and management have co-operated well during policy formulation. The majority of policies have been implemented for more than three years. A small number of companies in Fife appear to be interested in the development and implementation of written alcohol and smoking policies in the workplace.

Response to a Haemophilus influenzae type b diphtheria CRM197 conjugate vaccine in children with a defect of antibody production to Haemophilus influenzae type b polysaccharide

A defect in antibody response to immunization with Haemophilus influenzae type b (Hib) capsular polysaccharide vaccine has been reported in children with recurrent infections and normal immunoglobin levels. We identified 15 children, aged 2 to 6 years, with this defect, and we evaluated their response to immunization with an Hib capsular oligosaccharide diphtheria CRM197 protein-conjugate vaccine (HbOC). The children received a series of three vaccines: HbOC at 0 and 8 weeks, and the Hib polysaccharide vaccine at 16 weeks. Levels of antibody to the Hib capsular polysaccharide (polyribosyl ribitol phosphate, PRP) and to diphtheria toxoid were obtained before and 4 weeks after each vaccination. The geometric mean serum anti-PRP concentration was 0.17 microgram/ml before immunization and 29.3 micrograms/ml after the second HbOC immunization (week 12). All 15 children had postvaccination anti-PRP antibody levels greater than 1.0 microgram/ml after receiving the second HbOC (week 12). In addition, booster responses were observed after the second Hib conjugate in 13 of the patients and after the Hib polysaccharide in four of the patients. All patients with low preimmunization diphtheria titers had a response to the diphtheria toxoid. These results suggest that conjugation of Hib polysaccharide with diphtheria CRM197 overcomes the defective antibody response to Hib oligosaccharide in children who are initially observed with recurrent infections and inability to respond to the Hib polysaccharide vaccine.

Selective defect in the antibody response to Haemophilus influenzae type b in children with recurrent infections and normal serum IgG subclass levels

We studied 15 children with recurrent infections and normal serum IgG, IgM, IgA, and IgG-subclass levels. After immunization, the geometric mean serum IgG antibody concentration to Haemophilus influenzae type b (Hib) was eightfold lower than that of age-matched control subjects (p = 0.002). The patients also had a lower geometric mean concentration of serum IgM and IgA directed to Hib, although these differences did not reach significance. However, the groups did not differ in their response to diphtheria toxoid and pneumococcal polysaccharides. To confirm these findings, an additional 11 patients were identified and immunized. The geometric mean serum IgG anti-Hib concentration for this group of patients was also significantly lower than of normal subjects (p = 0.004). We propose that the defect in the antibody response to Hib may be a marker for a poor antibody response to a variety of bacterial and viral antigens that results in an increased propensity to recurrent infections. The defect was not associated with IgG-subclass deficiency. The identification of children with selective antibody deficiency and recurrent infections is important for diagnostic and therapeutic reasons.

Controlled trial of therapy in covert bacteriuria of childhood

Sixty-three girls with covert bacteriuria were included in a controlled trial of therapy. Recurrent infection in the treated group was common and was not significantly different from the rate of persistent infection in the untreated control group. Two children in each group developed clinical pyelonephritis; the others have remained healthy and all of them have a normal rate of growth. 2 years after diagnosis three of the thirty-four children in the control group and one of twenty-six children in the treated group have radiological evidence of new scars of pyelonephritis. These changes were relatively minor and in both groups of children renal growth was similar to that in normal children. It is suggested that for most of these children therapy is not essential, and that when renal changes occur they are of little or no significance. Prescriptive screening for cobert bacteriuria of childhood cannot be recommended at present.