Initial Pain Assessment and Management in Pediatric Burn Patients Presenting to a Major Trauma Center in Saudi Arabia

BACKGROUND

Pediatric burn injury is a traumatic experience for affected children and their families. Burn pain is frequently undertreated and may adversely affect patient experience and outcomes. The aim of this study was to investigate the current practice of initial pediatric burn pain assessment and management at a major trauma center in Riyadh, Kingdom of Saudi Arabia.

METHODS

We conducted a retrospective cohort study that included children 14 years and younger who visited King Saud Medical City in the Kingdom of Saudi Arabia with a presenting complaint of burn injury from January 01, 2017 to August 30, 2018. Variables were reported using descriptive statistics as appropriate.

RESULTS

The 309 patients who were analyzed were classified into 3 age groups ranging from 0 to younger than 3 years (61%), 3 to 7 years (24%), and older than 7 years (15%). They included 145 (47%) female and 164 (53%) male patients. Pain levels of 182 patients (59%) were documented using an age-appropriate tool. In 75 children (24%), pain levels were documented using an alternate tool, and the tool used was not defined for 44 children (14%). Pain assessment was not documented for 8 children. Of those with an age-appropriate tool, the median initial pain score was 4 (interquartile range [IQR], 2-4). Analgesia was recorded to have been administered to 139 patients (45%), within a median time of 50 minutes (IQR, 17-154 minutes) to first analgesia. Among patients who had appropriate assessment of pain, 92 (50.3%) received analgesia compared with 52 (41.3%) who did not have appropriate assessment (P = 0.12). Among patients who had appropriate pain assessment, time to analgesia was 42 minutes (IQR, 15-132 minutes) compared with 53 minutes (IQR, 17-189 minutes) among patients who did not have appropriate assessment (P = 0.48).

DISCUSSION

Most pediatric patients presenting with burns had pain assessment, but a substantial proportion of children were not managed using recommended age-specific tools. The use of age-specific tools was not necessarily associated with delivery of analgesia. For pediatric burns, prompt delivery of analgesia should be prioritized with pain assessment using age-appropriate tools being recommended, but optional.

The association of ketamine induction with blood pressure changes in paramedic rapid sequence intubation of out-of-hospital traumatic brain injury

INTRODUCTION

Rapid sequence intubation (RSI) is used to secure the airway of traumatic brain injury (TBI) patients, with ketamine frequently used for induction. Studies show that ketamine-induction RSI might cause lower blood pressures when compared to etomidate. It is not clear if the results from that research can be extrapolated to systems that use different dosing regimens for ketamine RSI. Ambulance Victoria authorized the use of 1.5 mg/kg ketamine in January 2015 for head injury RSI induction by road-based paramedics. This study aims to examine whether systolic blood pressure changed when ketamine was introduced for prehospital head injury RSI.

METHODS

This study was a retrospective analysis of out-of-hospital suspected TBI that received RSI by paramedics. Our analysis employs an interrupted time-series analysis (ITSA), which is a quasi-experimental method that tested whether hypotension and systolic blood pressures changed after the switch to ketamine induction in 2015. This ITSA utilized an ordinary least squares regression on complete observations using Newey-West standard errors.

RESULTS

During the study period, paramedics performed RSI in 8,613 patients, and 1,759 (20.4%) had a TBI. Ketamine usage increased by 52.7% in January 2015 (p < 0.001) after road-based paramedics were authorized to use ketamine induction. This analysis found significant 5% increase in post-RSI hypotension (p = 0.046) after the introduction of ketamine, and thereafter the incidence of post-RSI hypotension increased steadily by 0.5% every 3 months (p = 0.004). Concurrently, changes in systolic blood pressure, as measured by the interval just before induction to the last measured on scene, show an average decrease of 7.8 mm Hg (p = 0.04) at the start of 2015 with the ketamine rollout.

CONCLUSIONS

This ITSA shows that postinduction hypotension and also decreases in systolic blood pressures became evident after the introduction of ketamine. Further research to investigate the association between ketamine induction and survival is needed.

Paramedic student encounters with patients during clinical placements: A multi-institutional cohort study

OBJECTIVE

Paramedic students in the US are required to complete clinical placements to gain supervised experience with real patient encounters. Given wide variation in clinical placement practices, an evidence-based approach is needed to guide programs in setting realistic and attainable goals for students. This study's goal was to describe patient encounters and hours logged by paramedic students during clinical placements.

METHODS

A retrospective review of prospectively collected quality assurance data entered by US paramedic students between 2010 and 2014 was conducted. De-identified electronic records entered in the Field Internship Student Data Acquisition Project (FISDAP) Skill Tracker database were included from consenting paramedic students whose records were audited and approved by instructors. Descriptive statistics were calculated.

RESULTS

A total of 10,645 students encountered 2,239,027 patients; most encounters occurred in hospital settings (n = 1,311,967, 59%). The median total number of patient encounters per paramedic student was 206 (142-269) and the median total clinical placement hours per student was 626 (504-752). The median number of team leads per student was 56 (30-84). Students encountered a median of 22 (12-31) pediatric patients, ages 0-12 years, and 181 (126-238) adolescent or adult patients. For pediatric patient encounters, the most common clinical impressions were respiratory distress, other medical complaints, and extremity trauma. Among adult patient encounters, the most common clinical impressions included other medical, trauma, and cardiac conditions.

CONCLUSIONS

US paramedic students experienced a variable range of patient encounter types and volumes. The findings of this study offer an evidence base from which programs can set realistic and attainable clinical placement requirements.

Paramedic involvement in health education within metropolitan, rural and remote Australia: a narrative review of the literature

Objective A growing body of research indicates that paramedics may have a greater role to play in health care service provision, beyond the traditional models of emergency health care. The aim of this study was to identify and synthesise the literature pertaining to the role of paramedic-initiated health education within Australia, with specific consideration of metropolitan, rural and remote contexts. Methods A literature review was undertaken using the Ovid Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE and Scopus databases. The search time frame was limited from January 2007 to November 2017. The search was performed using key paramedic search terms in combination with keywords such as health education, rural, metropolitan, remote and Australia. Reference lists from relevant papers were also reviewed. Results Fourteen articles met the inclusion criteria for synthesis. Health education in the Australian paramedic context relates largely to expanded-scope paramedics, health promotion and the role of paramedics as key members of local communities. There were no studies specifically related to the paramedic role in health education, although many papers referred to health education as one of many roles paramedics engage in today. Conclusion This review highlights a broadening of paramedicine's traditional scope of practice, and an indication of how vital paramedics could be to local communities, particularly in rural and remote areas. An expanded role may help address health workforce sustainability problems in areas where health care provision is challenged by geographical constraints and low workforce numbers. What is known about the topic? A broadening of paramedicine's traditional scope of practice has been linked to improvements in health workforce sustainability problems in areas where health care provision is challenged by geographical constraints and low workforce numbers, such as rural and remote Australia. Health education, as well as health promotion, primary health care and chronic disease management, have been proposed as potential activities that paramedics could be well placed to participate in, contributing to the health and well-being of local communities. What does this paper add? This paper identifies and synthesises literature focusing on paramedic-initiated health education in the Australian context, assessing the current health education role of paramedics in metropolitan, rural and remote areas. It provides an understanding of different geographical areas that may benefit from expanded-scope prehospital practice, indicating that the involvement of paramedics in health education in Australia is significantly determined by their geographical place of work, reflecting the influence of the availability of healthcare resources on individual communities. What are the implications for practitioners? Today's paramedics fill broader roles than those encompassed within traditional models of prehospital care. Rural and remote communities facing increasing difficulty in obtaining health service provision appear to benefit strongly from the presence of expanded-scope paramedics trained in health promotion, primary injury prevention, chronic disease management and health education: this should be a consideration for medical and allied health practitioners in these areas. Australian paramedics are uniquely placed to 'fill the gaps' left by shortages of healthcare professionals in rural and remote areas of the country.

Review article: Emergency endotracheal intubation in non-traumatic brain pathologies: A systematic review and meta-analysis

Endotracheal intubation is an advanced airway procedure performed in the ED and the out-of-hospital setting for acquired brain injuries that include non-traumatic brain pathologies such as stroke, encephalopathies, seizures and toxidromes. Controlled trial evidence supports intubation in traumatic brain injuries, but it is not clear that this evidence can be applied to non-traumatic brain pathologies. We sought to analyse the impact of emergency intubation on survival in non-traumatic brain pathologies and also to quantify the prevalence of intubation in these pathologies. We conducted a systematic literature search of Medline, Embase and the Cochrane Library. Eligibility, data extraction and assessment of risk of bias were assessed independently by two reviewers. A bias-adjusted meta-analysis using a quality-effects model pooled prevalence of intubation in non-traumatic brain pathologies. Forty-six studies were included in this systematic review. No studies were suitable for meta-analysis the primary outcome of survival. Thirty-nine studies reported the prevalence of intubation in non-traumatic brain pathologies and a meta-analysis showed that emergency intubation was used in 12% (95% CI 0-33) of pathologies. Endotracheal intubation was used commonly in haemorrhagic stroke 79% (95% CI 47-100) and to a lesser extent for seizures 18% (95% CI 10-27) and toxidromes 25% (95% CI 6-48). This systematic review shows that there is no high-quality clinical evidence to support or refute emergency intubation in non-traumatic brain pathologies. Our analysis shows that intubation is commonly used in non-traumatic brain pathologies, and the need for rigorous evidence is apparent.

Potentially preventable trauma deaths: A retrospective review

BACKGROUND

Reviewing prehospital trauma deaths provides an opportunity to identify system improvements that may reduce trauma mortality. The objective of this study was to identify the number and rate of potentially preventable trauma deaths through expert panel reviews of prehospital and early in-hospital trauma deaths.

METHODS

We conducted a retrospective review of prehospital and early in-hospital (<24 h) trauma deaths following a traumatic out-of-hospital cardiac arrest that were attended by Ambulance Victoria (AV) in the state of Victoria, Australia, between 2008 and 2014. Expert panels were used to review cases that had resuscitation attempted by paramedics and underwent a full autopsy. Patients with a mechanism of hanging, drowning or those with anatomical injuries deemed to be unsurvivable were excluded.

RESULTS

Of the 1183 cases that underwent full autopsies, resuscitation was attempted by paramedics in 336 (28%) cases. Of these, 113 cases (34%) were deemed to have potentially survivable injuries and underwent expert panel review. There were 90 (80%) deaths that were not preventable, 19 (17%) potentially preventable deaths and 4 (3%) preventable deaths. Potentially preventable or preventable deaths represented 20% of those cases that underwent review and 7% of cases that had attempted resuscitation.

CONCLUSIONS

The number of potentially preventable or preventable trauma deaths in the pre-hospital and early in-hospital resuscitation phase was low. Specific circumstances were identified in which the trauma system could be further improved.

Experiential education enhancing paramedic perspective and interpersonal communication with older patients: a controlled study

BACKGROUND

Paramedics are required to provide care to an aging population with multidimensional and complex issues. As such educators need to prepare undergraduate paramedics to recognise, assess and manage a broad range of psychosocial care and support issues beyond somatic conditions. Experiential educational interventions with older people provide realistic and contextualised experience which can improve the provision of holistic patient focused care.

METHODS

This was a single institution controlled before-after study with parallel groups, conducted in Australia in 2017. It was designed to compare the effectiveness of an educational program related to older people (intervention), verses no intervention (control) on paramedic student attitudes, knowledge and behavior with older patients.

RESULTS

A total of 124 second year paramedic students were included in this study; 60 in the intervention and 64 in the control group. Their demographics and Time 1 baseline results were homogeneous. Both groups showed improvement in communication skills with real older patients (p < 0.001, η² = 0.41) and (p < 0.001, η² = 0.35). The intervention group showed greater improvements in the 'understands the patient's perspective' element for both the self-assessment (p < 0.001) and the clinician assessment (p = 0.01). Multiple linear regression Model 1 found gender (β = - 0.25; p = 0.01) was the best predictor of clinician-assessed communication, with females having higher scores. Knowledge and attitudes remained relatively unchanged for both groups.

CONCLUSIONS

As the first study to observe, measure and report on the interpersonal communication skills of paramedic student's with 'real' older patients we can report that these skills were from fair to good at baseline and improved from good to very good post the intervention. Overall improvement was notably better in the 'understanding the patients perspective element' for the intervention group who had conducted one-one visits with an older person.

Effectiveness of Workplace Interventions in Return-to-Work for Musculoskeletal, Pain-Related and Mental Health Conditions: An Update of the Evidence and Messages for Practitioners

Purpose The objective of this systematic review was to synthesize evidence on the effectiveness of workplace-based return-to-work (RTW) interventions and work disability management (DM) interventions that assist workers with musculoskeletal (MSK) and pain-related conditions and mental health (MH) conditions with RTW. Methods We followed a systematic review process developed by the Institute for Work & Health and an adapted best evidence synthesis that ranked evidence as strong, moderate, limited, or insufficient. Results Seven electronic databases were searched from January 1990 until April 2015, yielding 8898 non-duplicate references. Evidence from 36 medium and high quality studies were synthesized on 12 different intervention categories across three broad domains: health-focused, service coordination, and work modification interventions. There was strong evidence that duration away from work from both MSK or pain-related conditions and MH conditions were significantly reduced by multi-domain interventions encompassing at least two of the three domains. There was moderate evidence that these multi-domain interventions had a positive impact on cost outcomes. There was strong evidence that cognitive behavioural therapy interventions that do not also include workplace modifications or service coordination components are not effective in helping workers with MH conditions in RTW. Evidence for the effectiveness of other single-domain interventions was mixed, with some studies reporting positive effects and others reporting no effects on lost time and work functioning. Conclusions While there is substantial research literature focused on RTW, there are only a small number of quality workplace-based RTW intervention studies that involve workers with MSK or pain-related conditions and MH conditions. We recommend implementing multi-domain interventions (i.e. with healthcare provision, service coordination, and work accommodation components) to help reduce lost time for MSK or pain-related conditions and MH conditions. Practitioners should also consider implementing these programs to help improve work functioning and reduce costs associated with work disability.

Return to Work After Traumatic Injury: Increased Work-Related Disability in Injured Persons Receiving Financial Compensation is Mediated by Perceived Injustice

Purpose Traumatic injury is a leading cause of work disability. Receiving compensation post-injury has been consistently found to be associated with poorer return to work. This study investigated whether the relationship between receiving compensation and return to work was associated with elevated symptoms of psychological distress (i.e., anxiety, depression, and posttraumatic stress disorder) and perceived injustice. Methods Injured persons, who were employed at the time of injury (n = 364), were recruited from the Victorian State Trauma Registry, and Victorian Orthopaedic Trauma Outcomes Registry. Participants completed the Hospital Anxiety and Depression Scale, Posttraumatic Stress Disorder Checklist, Injustice Experience Questionnaire, and appraisals of pain and work status 12-months following traumatic injury. Results Greater financial worry and indicators of actual/perceived injustice (e.g., consulting a lawyer, attributing fault to another, perceived injustice, sustaining compensable injury), trauma severity (e.g., days in hospital and intensive care, discharge to rehabilitation), and distress symptoms (i.e., anxiety, depression, PTSD) led to a twofold to sevenfold increase in the risk of failing to return to work. Anxiety, post-traumatic stress and perceived injustice were elevated following compensable injury compared with non-compensable injury. Perceived injustice uniquely mediated the association between compensation and return to work after adjusting for age at injury, trauma severity (length of hospital, admission to intensive, and discharge location) and pain severity. Conclusions Given  that perceived injustice is associated with poor return to work after compensable injury, we recommend greater attention be given to appropriately addressing psychological distress and perceived injustice in injured workers to facilitate a smoother transition of return to work.

Prehospital Predictors of Traumatic Spinal Cord Injury in Victoria, Australia

OBJECTIVES

To identify the predictors of traumatic spinal cord injury (TSCI) and describe the differences between confirmed and potential TSCI cases in the prehospital setting.

METHODS

A retrospective cohort study including all adult patients over a six-year period (2007-12) with potential TSCI who were attended and transported by Ambulance Victoria (AV). We extracted potential TSCI cases from the AV data warehouse and linked with the Victorian State Trauma Registry to compare with final hospital diagnosis.

RESULTS

We included a total of 106,059 patients with potential TSCI in the study, with 257 having a spinal cord injury confirmed at hospital (0.2%). The median [First and third Quartiles] age of confirmed TSCI cases was 49 [32-69] years, with males comprising 84.1%. Confirmed TSCI were mainly due to falls (44.8%) and traffic incidents (40.5%). AV spinal care guidelines had a sensitivity of 100% to detect confirmed TSCI. There were several factors associated with a diagnosis of TSCI. These were meeting AV Potential Major Trauma criteria, male gender, presence of neurological deficit, presence of an altered state of consciousness, high falls (> 3 meters), diving, or motorcycle or bicycle collisions.

CONCLUSION

This study identified several predictors of TSCI including meeting AV Potential Major Trauma criteria, male gender, presence of neurological deficit, presence of an altered state of consciousness, high falls (> 3 meters), diving, or motorcycle or bicycle collisions. Most of these predictors are included in NEXUS and/or CCR criteria, however, Potential Major Trauma criteria have not previously been linked to the presence of TSCI. Therefore, Emergency Medical Systems are encouraged to integrate similar Potential Major Trauma criteria into their guidelines and protocols to further improve the provider's accuracy in identifying TSCI and to be more selective in their spinal immobilization, thereby reducing unwarranted adverse effects of this practice.

Endotracheal Cuff Pressure Changes During Helicopter Transport: A Systematic Review

OBJECTIVE

Cuff pressures are important in ventilated patients undergoing helicopter transport. An altitude-related increase in endotracheal tube (ETT) intracuff pressure has been shown in simulated hypobaric environments, model tracheas, and animal studies and may not accurately reflect in vivo pressures. The aim of this study was to determine if ETT intracuff pressure increases above the critical perfusion pressure of the trachea in ventilated patients during helicopter transport.

METHODS

Ovid Medline, CINAHL, Embase, Scopus, and the Cochrane Library were searched from their commencement to January 29, 2016. Google Scholar was searched, and reference lists of relevant articles were examined to identify additional studies. Articles were included if they reported on ETT intracuff pressure in ventilated patients during helicopter emergency medical service transport.

RESULTS

A total of 330 articles were identified; only 2 prospective observational studies met the inclusion criteria. The studies reported a mean cuff pressure increase of 23 cm H₂O and 33.9 cm H₂O. Both studies reported ETT intracuff pressure to frequently exceed the critical perfusion pressure of the tracheal mucosa during helicopter transport.

CONCLUSION

Further research with longitudinal follow-up is required to confirm these findings to determine if the effects of transient increased ETT intracuff pressure are clinically significant.

Consciousness induced during cardiopulmonary resuscitation: An observational study

BACKGROUND

Cardiopulmonary resuscitation-induced consciousness (CPRIC) is a phenomenon that has been described in only a handful of case reports. In this study, we aimed to describe CPRIC in out-of-hospital cardiac arrest (OHCA) patients and determine its association with survival outcomes.

METHODS

Retrospective study of registry-based data from Victoria, Australia between January 2008 and December 2014. Adult OHCA patients treated by emergency medical services (EMS) were included. Multivariable logistic regression was used to determine the association between CPRIC and survival to hospital discharge.

RESULTS

There were 112 (0.7%) cases of CPRIC among 16,558 EMS attempted resuscitations, increasing in frequency from 0.3% in 2008 to 0.9% in 2014 (p=0.004). Levels of consciousness consisted of spontaneous eye opening (20.5%), jaw tone (20.5%), speech (29.5%) and/or body movement (87.5%). CPRIC was independently associated with an increased odds of survival to hospital discharge in unwitnessed/bystander witnessed events (OR 2.09, 95% CI: 1.14, 3.81; p=0.02) but not in EMS witnessed events (OR 0.98, 95% CI: 0.49, 1.96; p=0.96). Forty-two (37.5%) patients with CPRIC received treatment with one or more of midazolam (35.7%), opiates (5.4%) or muscle relaxants (3.6%). When stratified by use of these medications, CPRIC in unwitnessed/bystander witnessed patients was associated with improved odds of survival to hospital discharge if medications were not given (OR 3.92, 95% CI: 1.66, 9.28; p=0.002), but did not influence survival if these medications were given (OR 0.97, 95% CI: 0.37, 2.57; p=0.97).

CONCLUSION

Although CPRIC is uncommon, its occurrence is increasing and may be associated with improved outcomes. The appropriate management of CPRIC requires further evaluation.

Barriers to conducting research: A survey of trainees in emergency medicine

OBJECTIVE

Research underpins evidence-based practice, but there are significant barriers to conducting research relevant to each clinical discipline. Understanding these barriers could allow strategies to reduce their impact. The present study was undertaken to understand specific barriers to research for emergency medicine (EM) trainees.

METHODS

EM trainees attending research short courses were surveyed. Free-text responses were classified into themes and a list of pre-specified potential barriers was used for ranking purposes.

RESULTS

The responders (n = 61/90; 67.8%) were young, mostly male with low confidence in leading a research project and limited previous research experience. There were 155 unique barriers identified from 55 respondents, which fitted into nine categories. The most frequently perceived barrier was time (29%), followed by skills (22.6%) and cultural factors (19.4%). Most trainees (n = 54/56, 96.4%) believed that the barriers could be overcome. Strategies suggested included protection of time, mentoring and education, as well as top-down improved research culture.

CONCLUSIONS

Barriers to research in EM are similar to other specialities and were perceived to be manageable. Reorganisation and refocus of the Australasian College for Emergency Medicine training curriculum may be an option to foster an environment to promote research.

The epidemiology of pre-hospital potential spinal cord injuries in Victoria, Australia: a six year retrospective cohort study

BACKGROUND

Traumatic Spinal Cord Injury (TSCI) is relatively uncommon, yet a devastating and costly condition. Despite the human and social impacts, studies describing patients with potential TSCI in the pre-hospital setting are scarce. This paper aims to describe the epidemiology of patients potentially at risk of or suspected to have a TSCI by paramedics, with a view to providing a better understanding of factors associated with potential TSCI.

METHODS

This is a retrospective cohort study of all adult patients managed and transported by Ambulance Victoria (AV) between 01 January 2007 and 31 December 2012 who, based on meeting pre-hospital triage protocols and criteria for spinal clearance, paramedic suspicion or spinal immobilisation, were classified to be at risk of or suspected to have a TSCI. Data was extracted from the AV data warehouse, including demographic details, trauma aetiology, paramedic assessment, management and other event characteristics.

RESULTS

A total of 106,059cases were included in the study, representing 2.3 % of all emergency transports by AV. Subjects had a median age of 51 years (interquartile range; 29-78) and 52.4 % were males (95 % CI 52-52.7). Males were significantly younger than females (M: 43 years [26-65] vs. F: 64 years [36-84], p =0.001). Falls and traffic accidents were the leading causes of injuries, comprising 46.9 and 39.4 % of cases, respectively. Other causes included accidents due to sport, animals, industrial work and diving, as well as violence and hanging. 29.9 % of patients were transported to a Major Trauma Service (MTS). A proportion of 48.8 % of the study population met the Pre-hospital Major Trauma criteria.

CONCLUSION

This is the first study to describe the epidemiology of potential TSCI in Australia and is based on a large, state-wide sample. It provides background knowledge and a baseline for future research, as well as a reference point for future in policy. Falling and traffic related injuries were the leading causes of potential SCI. Future research is required to identify the proportion of confirmed TSCI among the potentials and factors associated with TSCI in prehospital settings.

CPR-induced consciousness: A cross-sectional study of healthcare practitioners' experience

INTRODUCTION

Consciousness may occur during effective management of cardiac arrest and ranges from eye opening to interfering with rescuers' resuscitation attempts. Reported cases in the medical literature appear scant compared to anecdotal reports. The aim of this study was to evaluate health care providers' experience with consciousness during cardio-pulmonary resuscitation (CPR).

METHODS

A cross-sectional survey of 100 experienced health care professionals, including doctors, nurses and paramedics. Participants were asked about their experience with both CPR-non-interfering consciousness (e.g. eye opening, agonal breaths or mild restlessness) and CPR-interfering consciousness (e.g. purposeful movement, withdrawing from CPR, attempting to pull out airway-securing devices).

RESULTS

A third of responders reported attending more than 100 cases of arrests, while another third had attended 20 or less arrests. The responders had a mean of 11 (SD 8.7) years of practice. Most responders (59 of 67) to the question had experienced CPR-non-interfering consciousness and reported experiencing it a median of 3 (IQR 1-5) times. CPR-interfering consciousness had been experienced by 51 of the 63 responders and was experienced overall 1 (IQR 1-3) time. Management of these cases varied widely with varied opinion on ideal management ranging from no action to sedation and/or paralysis. A guideline describing the management of this presentation was considered necessary by 40 out of 57 (70%) responders.

CONCLUSIONS

Contrasting to a few reports in the medical literature, CPR-induced consciousness appears to be experienced more commonly during resuscitation. Management strategies varied widely and clinician opinion of ideal management was also varied. The desire for consensus guidelines on this topic exists. Acute care nurses are integral members of all resuscitation teams and in conjunction with other clinicians, ideally placed to develop, implement and disseminate such guidelines to delivering evidence based care to this sub-group of patients.

The epidemiology of pain in children treated by paramedics

OBJECTIVES

The present study aimed to describe paramedic assessment and management of pain in children in a large state-wide ambulance service.

METHODS

A retrospective cohort study included paediatric patients (aged less than 15 years) treated and transported by paramedics in the Australian state of Victoria between 1 January 2008 and 31 December 2011. Primary outcome measures were the frequency of analgesic administration and odds of receiving any analgesic (morphine, fentanyl or methoxyflurane). Data were analysed by descriptive statistics, χ(2) -test and logistic regression to test the association between analgesic administration and the explanatory variables.

RESULTS

There were 38 167 cases that included a description of pain and where any pain scores were >0. Median age was 10 years (IQR 5-12), 59.2% were male and 15 090 (39.5%) received any analgesic. Of patients reported to have severe pain (verbal numeric rating scale 8-10), only 45% (n = 6084) received any analgesia. In unadjusted analysis, patients aged >9 years were more likely to receive analgesia than those aged <3 years (unadjusted odds ratio 4.39, 95% confidence interval 4.01-4.80). Multiple regression analysis found that significant predictors of analgesic administration were patient's sex, patient age, type of pain, initial pain score and case year.

CONCLUSION

Disparities in analgesic administration based on age and the low rate of pain scores documented in very young children identified in the present study should inform strategies that aim to improve the assessment and management of pain in children.

Prediction of critical haemorrhage following trauma: A narrative review

Introduction: Traumatic haemorrhagic shock can be difficult to diagnose. Models for predicting critical bleeding and massive transfusion have been developed to aid clinicians. The aim of this review is to outline the various available models and report on their performance and validation. Methods: A review of the English and non-English literature in Medline, PubMed and Google Scholar was conducted from 1990 to September 2015. We combined several terms for i) haemorrhage AND ii) prediction, in the setting of iii) trauma. We included models that had at least two data points. We extracted information about the models, their developments, performance and validation. Results: There were 36 different models identified that diagnose critical bleeding, which included a total of 36 unique variables. All models were developed retrospectively. The models performed with variable predictive abilities–the most superior with an area under the receiver operating characteristics curve of 0.985, but included detailed findings on imaging and was based on a small cohort. The most commonly included variable was systolic blood pressure, featuring in all but five models. Pattern or mechanism of injury were used by 16 models. Pathology results were used by 15 models, of which nine included base deficit and eight models included haemoglobin. Imaging was utilised in eight models. Thirteen models were known to be validated, with only one being prospectively validated. Conclusions: Several models for predicting critical bleeding exist, however none were deemed accurate enough to dictate treatment. Potential areas of improvement identified include measures of variability in vital signs and point of care imaging and pathology testing.

Biphasic versus monophasic waveforms for transthoracic defibrillation in out-of-hospital cardiac arrest

BACKGROUND

Transthoracic defibrillation is a potentially life-saving treatment for people with ventricular fibrillation (VF) and haemodynamically unstable ventricular tachycardia (VT). In recent years, biphasic waveforms have become more commonly used for defibrillation than monophasic waveforms. Clinical trials of internal defibrillation and transthoracic defibrillation of short-duration arrhythmias of up to 30 seconds have demonstrated the superiority of biphasic waveforms over monophasic waveforms. However, out-of-hospital cardiac arrest (OHCA) involves a duration of VF/VT of several minutes before defibrillation is attempted.

OBJECTIVES

To determine the efficacy and safety of biphasic defibrillation waveforms, compared to monophasic, for resuscitation of people experiencing out-of-hospital cardiac arrest.

SEARCH METHODS

We searched the following electronic databases for potentially relevant studies up to 10 September 2014: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Also we checked the bibliographies of relevant studies and review articles, contacted authors of published reviews and reviewed webpages (including those of device manufacturers) relevant to the review topic. We handsearched the abstracts of conference proceedings for the American Heart Association, American College of Cardiology, European Society of Cardiology, European Resuscitation Council, Society of Critical Care Medicine and European Society of Intensive Care Medicine. Regarding language restrictions, we did not apply any.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared biphasic and monophasic waveform defibrillation in adults with OHCA. Two review authors independently screened the literature search results.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials and performed 'Risk of bias' assessments. We resolved any disagreements by discussion and consensus. The primary outcome was the risk of failure to achieve return of spontaneous circulation (ROSC). Secondary outcomes included risk of failure to revert VF to an organised rhythm following the first shock or up to three shocks, survival to hospital admission and survival to discharge.

MAIN RESULTS

We included four trials (552 participants) that compared biphasic and monophasic waveform defibrillation in people with OHCA. Based on the assessment of five quality domains, we identified two trials that were at high risk of bias, one trial at unclear risk of bias and one trial at low risk of bias. The risk ratio (RR) for failure to achieve ROSC after biphasic compared to monophasic waveform defibrillation was 0.86 (95% CI 0.62 to 1.20; four trials, 552 participants). The RR for failure to defibrillate on the first shock following biphasic defibrillation compared to monophasic was 0.84 (95% CI 0.70 to 1.01; three trials, 450 participants); and 0.81 (95% CI 0.61 to 1.09; two trials, 317 participants) for one to three stacked shocks. The RR for failure to achieve ROSC after the first shock was 0.92 (95% CI 0.81 to 1.04; two trials, 285 participants). Biphasic waveforms did not reduce the risk of death before hospital admission (RR 1.05, 95% CI 0.90 to 1.23; three trials, 383 participants) or before hospital discharge (RR 1.05, 95% CI 0.78 to 1.42; four trials, 550 participants). There was no statistically significant heterogeneity in any of the pooled analyses. None of the included trials reported adverse events.

AUTHORS' CONCLUSIONS

It is uncertain whether biphasic defibrillators have an important effect on defibrillation success in people with OHCA. Further large studies are needed to provide adequate statistical power.

Clinically meaningful reduction in pain severity in children treated by paramedics: a retrospective cohort study

INTRODUCTION

Pediatric pain is a common presenting symptom in the prehospital setting; however, there is a lack of data identifying factors associated with effective pain management in this population. We sought to identify the factors associated with clinically meaningful pain reduction in children.

METHODS

An analysis of electronic patient care records of all patients younger than 15 years presenting with pain to the emergency medical service of Victoria, Australia, over a 4-year period (2008-2011). Data were analyzed using descriptive statistics and multivariate regression to assess predictors of clinically meaningful pain reduction. Clinically meaningful pain reduction was defined as a reduction of 2 or more points on an 11-point scale.

RESULTS

A total of 92378 children were transported, of whom 15016 (16.3%) met the inclusion criteria. The median age was 11 (interquartile range, 9-13) years, and 59.2% were male. Patients older than 9 years were less likely (adjusted odds ratio [AOR], 0.5; 95% confidence interval [CI], 0.4-0.6) and boys were more likely (adjusted odds ratio, 1.1; 95% CI, 1.0-1.3) to have a clinically meaningful reduction in pain. Patients with pain classified as musculoskeletal were more likely to achieve a reduction in pain score of 2 or more when compared with pain due to other medical causes (AOR, 1.7; 95% CI, 1.5-1.9).

CONCLUSIONS

Factors other than the type of analgesia are important determinants of prehospital pain relief and are likely to impact on clinical care and research. Clinical audit and research projects should stratify patients according to patient as well as management factors to maximize service improvement.

Massive transfusion prediction with inclusion of the pre-hospital Shock Index

BACKGROUND

Detecting occult bleeding can be challenging and may delay resuscitation. The Shock Index (SI) defined as heart rate divided by systolic blood pressure has attracted attention. Prediction models using combinations of pre-hospital SI (phSI) and the trauma centre SI (tcSI) values may be effective in identifying patients requiring massive blood transfusions (MT).

AIM

To explore whether combinations of the phSI and the tcSI augment MT prediction.

METHODS

The scores were retrospectively developed using all major trauma patients that presented to The Alfred Hospital between 2006 and 2012. The first PH and TC observations were used. To avoid exclusion of the 'sickest' patients, the SI was imputed to 2 where SBP was missing, but HR was present. We developed 4 models. (i) 'Dichotomised', defined as positive when both phSI and tcSI were ≥1. (ii) 'Formulaic', defined by logistic regression analysis. (iii) 'Combination', defined pragmatically based on the logistic regression. (iv) 'Trending', defined as: tcSI minus phSI.

RESULTS

There were 6990 major trauma patients and 360 (5.2%) received MT. There were 1371 cases with either phSI or tcSI missing and were thus excluded from the analysis. The 'Dichotomised' had higher positive predictive value than the tcSI with a further 5 per 100 patients identified. The 'Formulaic' model, defined as: log Odds (MT)=2.16×tcSI+0.89×phSI-5.42, and the 'Combination' model, defined as: phSI×0.5+tcSI, performed equally (AUROC 0.83 versus 0.83, χ(2)=0.86, p=0.35). The 'Formulaic' performed marginally, but statistically significantly, more accurate than the tcSI alone (AUROC 0.83 versus 0.82, χ(2)=6.89, p<0.01). An 'Upward Trending' SI was observed in 1758 patients, revealing a 4.6-fold univariate association with MT (OR 4.55; 95%CI 2.64-7.83), and an AUROC of 0.79 (95%CI 0.74-0.83). The 'Downward Trending' SI was protective against MT (OR 0.44; 95%CI 0.34-0.57).

CONCLUSION

The initial pre-hospital SI is associated with MT. However, this relationship did not clinically augment MT decision when combined with the in-hospital SI. The simplicity of the SI makes it a favourable option to explore further. Computer-assisted technology in data capturing, analysis and prognostication presents avenues for further research.

Should suspected cervical spinal cord injury be immobilised?: a systematic review

BACKGROUND

Spinal cord injuries occur worldwide; often being life-threatening with devastating long term impacts on functioning, independence, health, and quality of life.

OBJECTIVES

Systematic review of the literature to determine the efficacy of cervical spinal immobilisation (vs no immobilisation) in patients with suspected cervical spinal cord injury (CSCI); and to provide recommendations for prehospital spinal immobilisation.

METHODS

Searches were conducted of the Cochrane library, CINAHL, EMBASE, Pubmed, Scopus, Web of science, Google scholar, and OvidSP (MEDLINE, PsycINFO, and DARE) databases. Studies were included if they were relevant to the research question, published in English, based in the prehospital setting, and included adult patients with traumatic injury.

RESULTS

The search identified 1471 citations, of which eight observational studies of variable quality were included. Four studies were retrospective cohorts, three were case series and one a case report. Cervical collar application was reported in penetrating trauma to be associated with unadjusted increased risk of mortality in two studies [(OR, 8.82; 95% CI, 1.09-194; p=0.038) & (OR, 2.06; 95% CI, 1.35-3.13)], concealment of neck injuries in one study and increased scene time in another study. While, in blunt trauma, one study indicated that immobilisation might be associated with worsened neurological outcome (OR, 2.03; 95% CI, 1.03-3.99; p=0.04, unadjusted). We did not attempt to combine study results due to significant heterogeneity of study design and outcome measures.

CONCLUSION

There is a lack of high-level evidence on the effect of prehospital cervical spine immobilisation on patient outcomes. There is a clear need for large prospective studies to determine the clinical benefit of prehospital spinal immobilisation as well as to identify the subgroup of patients most likely to benefit.

Scald burns in children aged 14 and younger in Australia and New Zealand—an analysis based on the Burn Registry of Australia and New Zealand (BRANZ)

INTRODUCTION

Scalds are a common injury in children and a frequent reason for hospitalisation despite being a preventable injury.

METHODS

This retrospective two year study reports data from 730 children aged 14 years or younger who sustained a scald between 2009 and 2010 and were admitted to a burns centre in Australia or New Zealand. Data were extracted from the Burn Registry of Australia and New Zealand (BRANZ), which included data from 13 burns centres in Australia and New Zealand.

RESULTS

Scald injury contributed 56% (95% CI 53-59%) of all pediatric burns. There were two high risk groups; male toddlers age one to two, contributing 34% (95% CI 31-38%) of all scalds, and indigenous children who were over 3 times more likely to experience a scald requiring admission to a burns unit than their non-indigenous peers. First aid cooling by non-professionals was initiated in 89% (95% CI 86-91%) of cases but only 20% (95% CI 16-23%) performed it as recommended.

CONCLUSION

This study highlights that effective burn first aid reduces hospital stay and reinforces the need to encourage, carers and bystanders to deliver effective first aid and the importance of targeted prevention campaigns that reduce the burden of pediatric scald burns in Australia and New Zealand.

Should suspected cervical spinal cord injuries be immobilised? A systematic review protocol

BACKGROUND

Cervical spinal cord injuries may result in life-threatening situations and long-term disability. Prehospital spinal immobilisation is the standard of care for patients with potential spinal cord injury (SCI). It aims to prepare patients for transport, achieve neutral spinal alignment, and reduce movement and secondary injuries in potentially unstable spines. However, there is a lack of evidence on its clinical benefits and its overall effect on patient outcomes.

OBJECTIVES

To identify the reported outcomes following immobilisation of suspected cervical SCI, to compare the effects of spinal immobilisation versus no immobilisation on the reported outcomes, and to provide recommendations for prehospital cervical immobilisation.

DESIGN/METHODS

A search of the literature will be conducted using relevant online databases. This will include all types of human studies that were published in English from the earliest record available to the first week of October 2013. One author will conduct the search and two independent authors will screen the titles and the abstracts identified by the search and critically appraise the selected papers. A third author will be available to resolve any disagreement. The findings will be reported according to Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Critical appraisal as well as the level and the strength of evidence will follow the National Health and Medical Research Council (NHMRC) guidelines.

DISCUSSION

Evidence-based practices should be pursued to further improve the prehospital care for suspected cervical SCI. This systematic review will contribute to the body of knowledge regarding the spinal immobilisation effects on the SCI patient's outcomes.

Next generation paramedics, agents of change, or time for curricula renewal?

BACKGROUND

Knowledge translation involves the dissemination and application of scientific research findings into clinical practice. In the health care arena, uptake of evidence-based assessment and intervention strategies is aimed at reducing inefficiencies and ultimately improving patient outcomes. However, numerous studies have purported gaps in knowledge translation in the health care professions. The objective of this study was to classify the traits of undergraduate paramedic students from Monash Univeristy, Australia, using the practice style inventory (PSI).

METHODS

A cross-sectional study of students across all undergraduate years from Emergency Health and Emergency Health/Nursing was completed. Student knowledge translation levels were measured using the 17-item paper-based PSI.

RESULTS

A total of 266 students participated in the study, of which 68.4% were females. The majority of participants were <26 years of age (n=228) and just over half enrolled in second year studies (n=134). Two subscales produced statistically significant differences: evidence versus experience (extent to which scientific evidence rather than authority is perceived as the best source of knowledge) and nonconformity (degree of comfort with clinical practices that are out of step with recommendations of leaders). There was a statistically significant difference between sex on the evidence versus experience subscale (P<0.0001, d =0.51), and between year levels on the nonconformity subscale (P<0.007, d =0.63).

CONCLUSION

This study identified several differences in knowledge translation subscales in the undergraduate paramedic cohorts. Further investigation is warranted in order to better understand barriers and facilitate improved uptake of evidence-based research into clinical practice and, ultimately, improve patient outcomes. Future research using a longitudinal study design to capture changing attitudes to knowledge translation in the postgraduate population may also prove valuable in curricula renewal.

Improving the hospital 'soundscape': a framework to measure individual perceptual response to hospital sounds

Work on the perception of urban soundscapes has generated a number of perceptual models which are proposed as tools to test and evaluate soundscape interventions. However, despite the excessive sound levels and noise within hospital environments, perceptual models have not been developed for these spaces. To address this, a two-stage approach was developed by the authors to create such a model. First, semantics were obtained from listening evaluations which captured the feelings of individuals from hearing hospital sounds. Then, 30 participants rated a range of sound clips representative of a ward soundscape based on these semantics. Principal component analysis extracted a two-dimensional space representing an emotional-cognitive response. The framework enables soundscape interventions to be tested which may improve the perception of these hospital environments.

WITHDRAWN: Scald burns in children aged 14 and younger in Australia and New Zealand-An analysis based on the Bi-National Burns Registry (BiNBR)

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Early aggregated States in the folding of interleukin-1β

Kinetic data measured from folding of the protein interleukin-1β fits best to three exponential phases when studied with tryptophan fluorescence but only two exponential phases when measured using other methods. The technique of ANS fluorescence was used to determine whether the additional phase observed in tryptophan fluorescence was also detected with ANS dye binding. Unlike trytophan fluorescence, the ANS fluorescence was highly dependent on the concentration of protein present during the folding experiment. Experimental controls provide evidence that ANS binds to protein aggregates, present at higher concentrations and absent at lower concentrations. Protein concentration-dependent folding studies demonstrate that, at lower interleukin-1β concentrations, tryptophan fluorescence kinetics can be fit adequately with a two exponential fit. This study indicates that (1) measured interleukin-1β folding kinetics fit to a 2 phase model and (2) at higher protein concentrations, transient association of IL-1β may result in a kinetic fit of 3 phases.

An automated CPR device compared with standard chest compressions for out-of-hospital resuscitation

Background

Effective cardiopulmonary resuscitation and increased coronary perfusion pressures have been linked to improved survival from cardiac arrest. This study aimed to compare the rates of survival between conventional cardiopulmonary resuscitation (C-CPR) and automated CPR (A-CPR) using AutoPulse™ in adults following out-of-hospital cardiac arrest (OHCA).

Methods

This was a retrospective study using a matched case–control design across three regional study sites in Victoria, Australia. Each case was matched to at least two (maximum four) controls using age, gender, response time, presenting cardiac rhythm and bystander CPR, and analysed using conditional fixed-effects logistic regression.

Results

During the period 1 October 2006 to 30 April 2010 there were 66 OHCA cases using A-CPR. These were matched to 220 cases of OHCA involving the administration of C-CPR only (controls). Survival to hospital was achieved in 26% (17/66) of cases receiving A-CPR compared with 20% (43/220) of controls receiving C-CPR and the propensity score adjusted odds ratio [AOR (95% CI)] was 1.69 (0.79, 3.63). Results were similar using only bystander witnessed OHCA cases with presumed cardiac aetiology. Survival to hospital was achieved for 29% (14/48) of cases receiving A-CPR compared with 18% (21/116) of those receiving C-CPR [AOR = 1.80 (0.78, 4.11)].

Conclusions

The use of A-CPR resulted in a higher rate of survival to hospital compared with C-CPR, yet a tendency for a lower rate of survival to hospital discharge, however these associations did not reach statistical significance. Further research is warranted which is prospective in nature, involves randomisation and larger number of cases to investigate potential sub-group benefits of A-CPR including survival to hospital discharge.

Determinants of clinically important pain severity reduction in the prehospital setting

This retrospective, electronic patient care record review examined a consecutive sample of patients presenting with pain to the metropolitan region of Ambulance Victoria over a 12 month period in 2008. Seven factors were found to be associated with the likelihood of clinically important pain reduction following multivariate analyses. These included age, time criticality of the patient, pain aetiology, initial pain severity, analgesic agent or combination administered to the patient and prehospital time.

Barriers to incident notification in a regional prehospital setting

BACKGROUND

The identification and monitoring of critical incidents or adverse events and error reporting is a relatively new area of study in the prehospital setting. In 2005, we commenced a prospective descriptive study of the implementation of a Critical Incident Monitoring process in a rural/regional pre-hospital setting. The objective of the project was to describe the nature and incidence of errors detected in the management of prehospital trauma with the ultimate aim of identifying processes to reduce or mitigate such incidents. This paper describes the barriers to reporting critical incidents identified during the 3-year study.

METHOD

This study used a qualitative approach involving the triangulation of a number of ethnographic methodologies, including unscripted focus groups, informal interviews and qualitative aspects of surveys utilised in a broader research project. Prevailing themes were fed back to participants in an iterative process to further explore perceptions and beliefs regarding these concepts. The final analysis of themes is descriptively presented.

RESULTS

A number of barriers were identified and categorised into seven themes. These themes were; Burden of reporting, fear of disciplinary action, fear of potential litigation, fear of breaches of confidentiality and fear of embarrassment, concern that 'nothing would change' even if the incident was reported, lack of familiarity with process and impact of 'blame culture'.

CONCLUSION

There are numerous barriers to reporting critical incidents. One of the key approaches which may alleviate many of the barriers to reporting is shifting to a systems based focus rather than an individual 'shame and blame' approach. The underlying barriers lie in the culture of the profession, and appear consistent across other health care disciplines.

Measuring acute pain in the prehospital setting

Severe pain is a common presenting symptom for emergency patients. One major challenge in the management of severe pain is the objective measurement of pain. Due to the subjective nature of pain, it can be very difficult for clinicians to quantify pain intensity and measure the qualitative features of the pain experience. A number of measurement tools have been validated in the acute care setting, with some appropriate for use in the prehospital setting. This paper reviews the characteristics required of a prehospital acute pain measure and appraises the relative utility of a number of currently used pain measures. At present, the verbal numerical rating scale appears the most appropriate pain measure to administer in the prehospital setting for adult patients as it is practical and valid. Either the Oucher scale or the faces pain scale is suitable for prehospital care providers to assess pain in children.

Out‐of‐hospital cardiac arrest in Victoria: rural and urban outcomes

OBJECTIVE

To compare the survival rate from out-of-hospital cardiac arrest in rural and urban areas of Victoria, and to investigate the factors associated with these differences.

DESIGN

Retrospective case series using data from the Victorian Ambulance Cardiac Arrest Registry.

SETTING

All out-of-hospital cardiac arrests occurring in Victoria that were attended by Rural Ambulance Victoria or the Metropolitan Ambulance Service.

PARTICIPANTS

1790 people who suffered a bystander-witnessed cardiac arrest between January 2002 and December 2003.

RESULTS

Bystander cardiopulmonary resuscitation was more likely in rural (65.7%) than urban areas (48.4%) (P = 0.001). Urban patients with bystander-witnessed cardiac arrest were more likely to arrive at an emergency department with a cardiac output (odds ratio [OR], 2.92; 95% CI, 1.65-5.17; P < 0.001), and to be discharged from hospital alive than rural patients (urban, 125/1685 [7.4%]; rural, 2/105 [1.9%]; OR, 4.13; 95% CI, 1.09-34.91). Major factors associated with survival to hospital admission were distance of cardiac arrest from the closest ambulance branch (OR, 0.87; 95% CI, 0.82-0.92), endotracheal intubation (OR, 3.46; 95% CI, 2.49-4.80), and the presence of asystole (OR, 0.50; 95% CI, 0.38-0.67) or pulseless electrical activity (OR, 0.73; 95% CI, 0.56-0.95) on arrival of the first ambulance crew.

CONCLUSIONS

Survival rates differ between urban and rural cardiac arrest patients. This is largely due to a difference in ambulance response time. As it is impractical to substantially decrease response times in rural areas, other strategies that may improve outcome after cardiac arrest require investigation.

Proton transfer dynamics of GART: the pH-dependent catalytic mechanism examined by electrostatic calculations

The enzyme glycinamide ribonucleotide transformylase (GART) catalyzes the transfer of a formyl group from formyl tetrahydrofolate (fTHF) to glycinamide ribonucleotide (GAR), a process that is pH-dependent with pK(a) of approximately 8. Experimental studies of pH-rate profiles of wild-type and site-directed mutants of GART have led to the proposal that His108, Asp144, and GAR are involved in catalysis, with His108 being an acid catalyst, while forming a salt bridge with Asp144, and GAR being a nucleophile to attack the formyl group of fTHF. This model implied a protonated histidine with pK(a) of 9.7 and a neutral GAR with pK(a) of 6.8. These proposed unusual pK(a)s have led us to investigate the electrostatic environment of the active site of GART. We have used Poisson-Boltzmann-based electrostatic methods to calculate the pK(a)s of all ionizable groups, using the crystallographic structure of a ternary complex of GART involving the pseudosubstrate 5-deaza-5,6,7,8-THF (5dTHF) and substrate GAR. Theoretical mutation and deletion analogs have been constructed to elucidate pairwise electrostatic interactions between key ionizable sites within the catalytic site. Also, a construct of a more realistic catalytic site including a reconstructed pseudocofactor with an attached formyl group, in an environment with optimal local van der Waals interactions (locally minimized) that imitates closely the catalytic reactants, has been used for pK(a) calculations. Strong electrostatic coupling among catalytic residues His108, Asp144, and substrate GAR was observed, which is extremely sensitive to the initial protonation and imidazole ring flip state of His108 and small structural changes. We show that a proton can be exchanged between GAR and His108, depending on their relative geometry and their distance to Asp144, and when the proton is attached on His108, catalysis could be possible. Using the formylated locally minimized construct of GART, a high pK(a) for His108 was calculated, indicating a protonated histidine, and a low pK(a) for GAR(NH(2)) was calculated, indicating that GAR is in neutral form. Our results are in qualitative agreement with the current mechanistic picture of the catalytic process of GART deduced from the experimental data, but they do not reproduce the absolute magnitude of the pK(a)s extracted from fits of k(cat)-pH profiles, possibly because the static time-averaged crystallographic structure does not describe adequately the dynamic nature of the catalytic site during binding and catalysis. In addition, a strong effect on the pK(a) of GAR(NH(2)) is produced by the theoretical mutations of His108Ala and Asp144Ala, which is not in agreement with the observed insensitivity of the pK(a) of GAR(NH(2)) modeled from the experimental data using similar mutations. Finally, we show that important three-way electrostatic interactions between highly conserved His137, with His108 and Asp144, are responsible for stabilizing the electrostatic microenvironment of the catalytic site. In conclusion, our data suggest that further detailed computational and experimental work is necessary.

Native-state conformational dynamics of GART: a regulatory pH-dependent coil-helix transition examined by electrostatic calculations

Glycinamide ribonucleotide transformylase (GART) undergoes a pH-dependent coil-helix transition with pK(a) approximately 7. An alpha-helix is formed at high pH spanning 8 residues of a 21-residue-long loop, comprising the segment Thr120-His121-Arg122-Gln123-Ala124-Leu125-Glu126-Asn127. To understand the electrostatic nature of this loop-helix, called the activation loop-helix, which leads to the formation and stability of the alpha-helix, pK(a) values of all ionizable residues of GART have been calculated, using Poisson-Boltzmann electrostatic calculations and crystallographic data. Crystallographic structures of high and low pH E70A GART have been used in our analysis. Low pK(a) values of 5.3, 5.3, 3.9, 1.7, and 4.7 have been calculated for five functionally important histidines, His108, His119, His121, His132, and His137, respectively, using the high pH E70A GART structure. Ten theoretical single and double mutants of the high pH E70A structure have been constructed to identify pairwise interactions of ionizable residues, which have aided in elucidating the multiplicity of electrostatic interactions of the activation loop-helix, and the impact of the activation helix on the catalytic site. Based on our pK(a) calculations and structural data, we propose that: (1) His121 forms a molecular switch for the coil-helix transition of the activation helix, depending on its protonation state; (2) a strong electrostatic interaction between His132 and His121 is observed, which can be of stabilizing or destabilizing nature for the activation helix, depending on the relative orientation and protonation states of the rings of His121 and His132; (3) electrostatic interactions involving His119 and Arg122 play a role in the stability of the activation helix; and (4) the activation helix contains the helix-promoting sequence Arg122-Gln123-Ala124-Leu125-Glu126, but its alignment relative to the N and C termini of the helix is not optimal, and is possibly of a destabilizing nature. Finally, we provide electrostatic evidence that the formation and closure of the activation helix create a hydrophobic environment for catalytic-site residue His108, to facilitate catalysis.

A universal protein-protein interaction motif in the eubacterial DNA replication and repair systems

The interaction between DNA polymerases and sliding clamp proteins confers processivity in DNA synthesis. This interaction is critical for most DNA replication machines from viruses and prokaryotes to higher eukaryotes. The clamp proteins also participate in a variety of dynamic and competing protein-protein interactions. However, clamp-protein binding sequences have not so far been identified in the eubacteria. Here we show from three lines of evidence, bioinformatics, yeast two-hybrid analysis, and inhibition of protein-protein interaction by modified peptides, that variants of a pentapeptide motif (consensus QL[SD]LF) are sufficient to enable interaction of a number of proteins with an archetypal eubacterial sliding clamp (the beta subunit of Escherichia coli DNA polymerase III holoenzyme). Representatives of this motif are present in most sequenced members of the eubacterial DnaE, PolC, PolB, DinB, and UmuC families of DNA polymerases and the MutS1 mismatch repair protein family. The component tripeptide DLF inhibits the binding of the alpha (DnaE) subunit of E. coli DNA polymerase III to beta at microM concentration, identifying key residues. Comparison of the eubacterial, eukaryotic, and archaeal sliding clamp binding motifs suggests that the basic interactions have been conserved across the evolutionary landscape.

Prediction of folding mechanism for circular-permuted proteins

Recent theoretical and experimental studies have suggested that real proteins have sequences with sufficiently small energetic frustration that topological effects are central in determining the folding mechanism. A particularly interesting and challenging framework for exploring and testing the viability of these energetically unfrustrated models is the study of circular-permuted proteins. Here we present the results of the application of a topology-based model to the study of circular permuted SH3 and CI2, in comparison with the available experimental results. The folding mechanism of the permuted proteins emerging from our simulations is in very good agreement with the experimental observations. The differences between the folding mechanisms of the permuted and wild-type proteins seem then to be strongly related to the change in the native state topology.

Structural characterization of protein kinase A as a function of nucleotide binding. Hydrogen-deuterium exchange studies using matrix-assisted laser desorption ionization-time of flight mass spectrometry detection

Transient state kinetic studies indicate that substrate phosphorylation in protein kinase A is partially rate-limited by conformational changes, some of which may be associated with nucleotide binding (Shaffer, J., and Adams, J. A. (1999) Biochemistry 38, 12072-12079). To assess whether specific structural changes are associated with the binding of nucleotides, hydrogen-deuterium exchange experiments were performed on the enzyme in the absence and presence of ADP. Four regions of the protein are protected from exchange in the presence of ADP. Two regions encompass the catalytic and glycine-rich loops and are integral parts of the active site. Conversely, protection of probes in the C terminus is consistent with nucleotide-induced domain closure. One protected probe encompasses a portion of helix C, a secondary structural element that does not make any direct contacts with the nucleotide but has been reported to undergo segmental motion upon the activation of some protein kinases. The combined data suggest that binding of the nucleotide has distal structural effects that may include stabilizing the closed state of the enzyme and altering the position of a critical helix outside the active site. The latter represents the first evidence that the nucleotide alone can induce changes in helix C in solution.

Core and surface mutations affect folding kinetics, stability and cooperativity in IL-1 beta: does alteration in buried water play a role?

Interleukin-1 beta (IL-1 beta) is a cytokine and a member of the beta-trefoil superfamily of protein structures. An interesting feature in the folding of IL-1 beta, shared with some other members of the same topological family, is the existence of a slow step in folding to the native conformation from a discrete intermediate. Wanting to probe the nature of this slow step in the folding of WT IL-1 beta (tau(1)=45 seconds), we made ten sequence variants of IL-1 beta (L10A, T9Q, T9G, C8S, C8A, N7G, N7D, L6A, R4P, and R4Q), where all mutations are located along strand 1. This strand is not protected from hydrogen exchange until late in folding. Most of the mutations showed little effect on the kinetics of folding for IL-1 beta. However, C8 is clearly involved in both the late and the early steps in folding, while sequence variants at L10 and L6 affect only late events in folding. The value of the slowest relaxation time, tau(1), which is associated with the rate of native protein formation, increased for the refolding of C8S, while C8A, L6A, and L10A showed smaller but systematic increases in the value of tau(1.)For both C8S and C8A, the value of the step associated with formation of the intermediate, tau(2), was independent of denaturant concentration. In addition, mutations in the hydrophobic core (L10A, C8A, C8S, and L6A) and, surprisingly, along the surface (T9G, T9Q, and N7G) alter the stability. The most destabilizing mutations show changes in equilibrium unfolding cooperativity, which is atypical for destabilizing mutations in IL-1 beta. Crystallographic studies indicate that mutations along strand 1 may alter the number of ordered water molecules within the core. Thus, side-chain replacement in this region can disrupt essential main-chain interactions mediated by ordered water contacts in a highly cooperative network of hydrogen bonding.

Commitment to folded and aggregated states occurs late in interleukin-1 beta folding

A point mutation, lysine 97 to isoleucine, in the all-beta cytokine interleukin-1 beta (IL-1 beta) exhibits an increased propensity to form inclusion bodies in vivo and aggregates in vitro. In an effort to better understand the aggregation reaction and determine when intervention may allow rescue of protein from aggregation during renaturation, we developed a novel application of mass spectrometry using isotopic labeling to determine the step(s) at which K97I commits to either the native or aggregated state. Interestingly, despite the early formation of a folding intermediate ensemble at an observed rate lambda(2) of 4.0 s(-1), K97I commits to folding at a significantly slower rate lambda(CF) of 0.021 s(-1). This rate of commitment to folding is in excellent agreement with the observed rate of K97I native state formation (lambda(1) = 0.018 s(-1)). K97I also commits slowly to aggregation at an observed rate lambda(CA) of 0.023 s(-1). Earlier folding species and aggregates present prior to these commitment steps are likely to be in a reversible equilibrium between monomeric folding intermediates and higher-order oligomers. Kinetic and equilibrium experimental measurements of folding and aggregation processes are consistent with a nucleation-dependent model of aggregation.

Isoform-specific differences between the type Ialpha and IIalpha cyclic AMP-dependent protein kinase anchoring domains revealed by solution NMR

Cyclic AMP dependent protein kinase (PKA) is controlled, in part, by the subcellular localization of the enzyme (). Discovery of dual specificity anchoring proteins (d-AKAPs) indicates that not only is the type II, but also the type I, enzyme localized (). It appears that the type I enzyme is localized in a novel, dynamic fashion as opposed to the apparent static localization of the type II enzyme. Recently, the structure of the dimerization/docking (D/D) domain from the type II enzyme was solved (). This work revealed an X-type four-helix bundle motif with a hydrophobic patch that modulates AKAP interactions. To understand the dynamic versus static localization of PKA, multidimensional NMR techniques were used to investigate the structural features of the type I D/D domain. Our results indicate a conserved helix-turn-helix motif in the type I and type II D/D domains. However, important differences between the two domains are evident in the extreme NH(2) terminus: this region is extended in the type II domain, whereas it is helical in the type I protein. The NH(2)-terminal residues in RIIalpha contain determinants for anchoring, and the orientation and packing of this helical element in the RIalpha structure may have profound consequences in the recognition surface presented to the AKAPs.

An essential intermediate in the folding of dihydrofolate reductase

The folding of Escherichia coli dihydrofolate reductase was examined at pH 7.8 and 15 degrees C by using stopped-flow fluorescence and absorbance spectroscopies. The formation of a highly fluorescent intermediate occurs with relaxation times ranging between 142 and 343 msec, whereas stopped-flow absorbance spectroscopy using methotrexate binding assays shows a distinct lag phase during these time frames for the native state. The lag in absorbance kinetics and the lack of fast-track folding events indicate that the formation of this ensemble of intermediates is an obligatory step in the folding reaction.

How native-state topology affects the folding of dihydrofolate reductase and interleukin-1beta

The overall structure of the transition-state and intermediate ensembles observed experimentally for dihydrofolate reductase and interleukin-1beta can be obtained by using simplified models that have almost no energetic frustration. The predictive power of these models suggests that, even for these very large proteins with completely different folding mechanisms and functions, real protein sequences are sufficiently well designed, and much of the structural heterogeneity observed in the intermediates and the transition-state ensembles is determined by topological effects.

Aggregation events occur prior to stable intermediate formation during refolding of interleukin 1beta

A point mutation, lysine 97 --> isoleucine (K97I), in a surface loop in the beta-sheet protein interleukin 1beta (IL-1beta), exhibits increased levels of inclusion body (IB) formation relative to the wild-type protein (WT) when expressed in Escherichia coli. Despite the common observation that less stable proteins are often found in IBs, K97I is more stable than WT. We examined the folding pathway of the mutant and wild-type proteins at pH 6.5 and 25 degrees C with manual-mixing and stopped-flow optical spectroscopy to determine whether changes in the properties of transiently populated species in vitro correlate with the observation of increased aggregation in vivo. The refolding reactions of the WT and K97I proteins are both described by three exponential processes. Two exponential processes characterize fast events (0.1-1.0 s) in folding while the third exponential process correlates with a slow (70 s) single pathway to and from the native state. The K97I replacement affects the earlier steps in the refolding pathway. Aggregation, absent in the WT refolding reaction, occurs in K97I above a critical protein concentration of 18 microM. This observation is consistent with an initial nucleation step mediating protein aggregation. Stopped-flow kinetic studies of the K97I aggregation process demonstrate that K97I aggregates most rapidly during the earliest refolding times, when unfolded protein conformers remain highly populated and the concentration of folding intermediates is low. Folding and aggregation studies together support a model in which the formation of stable folding intermediates afford protection against further K97I aggregation.

The molecular basis for protein kinase A anchoring revealed by solution NMR

Compartmentalization of signal transduction enzymes into signaling complexes is an important mechanism to ensure the specificity of intracellular events. Formation of these complexes is mediated by specialized protein motifs that participate in protein-protein interactions. The adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) is localized through interaction of the regulatory (R) subunit dimer with A-kinase-anchoring proteins (AKAPs). We now report the solution structure of the type II PKA R-subunit fragment RIIalpha(1-44), which encompasses both the AKAP-binding and dimerization interfaces. This structure incorporates an X-type four-helix bundle dimerization motif with an extended hydrophobic face that is necessary for high-affinity AKAP binding. NMR data on the complex between RIIalpha(1-44) and an AKAP fragment reveals extensive contacts between the two proteins. Interestingly, this same dimerization motif is present in other signaling molecules, the S100 family. Therefore, the X-type four-helix bundle may represent a conserved fold for protein-protein interactions in signal transduction.