'I just need to find out if I had broken something or not.' A qualitative descriptive study into patient decisions to present to an Emergency Department with a simple fracture.

Background To investigate what factors contribute to a working age adult with a simple fracture seeking care in an Australian metropolitan Emergency Department (ED) Methods In this Qualitative Descriptive study, we interviewed ED patients with simple fractures including 5th metacarpal, 5th metatarsal, toe, radial head and clavicle fractures. Results We interviewed 30 patients aged 18-65. Two thirds of participants were aware they might have a minor injury. Many were well informed health consumers and convenience was the most important decision-making factor. Participants focussed on organising imaging, diagnosis and immobilisation. This sequence of care was often perceived as more complex and inefficient in primary care. ED was trusted and preferred to urgent primary care with an unknown doctor. Some patients defaulted to attending ED without considering alternatives due to poor health system knowledge or from escalating anxiety. Conclusions ED is safe, free and equipped to manage simple and complex injuries. Patients would attend primary care if comprehensive fracture management was easily accessible from a trusted clinician. To effectively divert simple fracture presentations from ED, primary care requires collocated imaging, imaging interpretation, orthopaedic expertise, and fracture management resources. Services need to operate 7 days a week and must have accessible 'urgent' appointments.

Fracture liaison service utilising an emergency department information system to identify patients effectively reduce re-fracture rate is cost-effective and cost saving in Western Australia.

OBJECTIVES: To assess the benefits of the Emergency Department Information System (EDIS)-linked fracture liaison service (FLS). METHODS: Patients identified through EDIS were invited to attend an FLS at the intervention hospital, the Sir Charles Gairdner Hospital (SCGS-FLS). The intervention group was compared to usual care. Retrospective control (RC) at this hospital determined historical fracture risk (SCGH-RC). Prospective control (PC) was from a comparator, Fremantle Hospital (FH-PC). The main outcome measures were cost-effectiveness from a health system perspective and quality of life by EuroQOL (EQ-5D). Bottom-up cost of medical care, against the cost of managing recurrent fracture (weighted basket), was determined from the literature and 2013/14 Australian Refined Diagnosis Related Groups (AR-DRG) prices. Mean incremental cost-effectiveness ratios were simulated from 5000 bootstrap iterations. Cost-effectiveness acceptability curves were generated. RESULTS: The SCGH-FLS program reduced absolute re-fracture rates versus control cohorts (9.2-10.2%), producing an estimated cost saving of AUD$750,168-AUD$810,400 per 1000 patient-years in the first year. Between-groups QALYs differed with worse outcomes in both control groups (p < 0.001). The SCGH-FLS compared with SCGH-RC and FH-PC had a mean incremental cost of $8721 (95% CI -$1218, $35,044) and $8974 (95% CI -$26,701, $69,929), respectively, per 1% reduction in 12-month recurrent fracture risk. The SCGH-FLS compared with SCGH-RC and FH-PC had a mean incremental cost of $292 (95% CI -$3588, $3380) and -$261 (95% CI -$1521, $471) per EQ-5D QALY gained at 12 months respectively. With societal willingness to pay of $16,000, recurrent fracture is reduced by 1% in >80% of patients. CONCLUSIONS: This simple and easy model of identification and intervention demonstrated efficacy in reducing rates of recurrent fracture and was cost-effective and potentially cost saving.

The use of computed tomography in the management of injury in tertiary emergency departments in Western Australia: Evidence of overtesting?

BACKGROUND: This study investigated trends in computed tomography (CT) utilization across different triage categories of injury presentations to tertiary emergency departments (EDs) and associations with diagnostic yield measured by injury severity, hospitalization and length of stay (LOS), and mortality. METHODS: A total of 411,155 injury-related ED presentations extracted from linked records from Western Australia from 2004 to 2015 were included in the retrospective study. The use of CT scanning and diagnostic yield measured by rate of diagnosis with severe injury, hospitalizations and LOS, and mortality were captured annually for injury-related ED presentations. Multivariable regression models were used to calculate the annual adjusted rate of CT scanning for injury presentations and hospitalizations across triage categories, diagnosis with severe injury, LOS, and mortality. The significance of changes observed was compared among patients with CT imaging relative to those without CT. RESULTS: While the number of ED presentations with injury increased by 65% from 2004 to 2015, the use of CT scanning in these presentations increased by 176%. The largest increase in CT use was among ED presentations triaged as semi-/nonurgent (+256%). Injury presentations with CT, compared to those without, had a higher rate of diagnosis with moderate/severe injury and hospitalization but no difference in LOS and mortality. The probability/rate observed in the outcomes of interest had a greater decrease over time in those with CT scanning compared with those without CT scanning across triage categories. CONCLUSIONS: The reduction in diagnostic yield in terms of injury severity and hospitalization found in our study might indicate a shift toward overtesting using CT in ED for injury or a higher use of CT to assist in the management of injuries. This helps health care policymakers consider whether the current increase in CT use meets the desired levels of quality and efficient care.

Inner hair cell stereocilia displacement in response to focal stimulation of the basilar membrane in the ex vivo gerbil cochlea.

The inner hair cells in the mammalian cochlea transduce mechanical signals to electrical signals that provide input to the auditory nerve. The spatial-temporal displacement of the inner hair cell stereocilia (IHCsc) relative to basilar membrane (BM) displacement is central to characterizing the transduction process. This study specifically focuses on measuring displacement of the stereocilia hair bundles in the radial dimensions where they are most sensitive. To simplify the mechanical response of the cochlear partition, a mechanical probe was used to drive the BM. Optical imaging was used to measure radial displacement of the inner hair cell stereocilia local to the probe in ex vivo gerbil cochleae. The mechanical probe displaced the BM in the transverse direction using sinusoidal stimuli with frequencies ranging from 10 Hz to 42.5 kHz. IHCsc displacement measurements were made in the radial dimension as a function of their longitudinal location along the length of the BM. The results were used to quantify the frequency response, longitudinal space coupling, traveling wave velocity, and wavelength of the radial displacement of the stereocilia. The measurements were centered at two best frequency locations along the BM: Proximal to the round window (first turn), and in the second turn. At both locations, frequency tuning was seen that was consistent with published place maps. At both locations, traveling waves were observed simultaneously propagating basal and apical from the probe. The velocity of the traveling waves at the center frequency (CF) of the location was higher in the first turn than in the second. As the stimulus frequency increased and approached CF for a location, the traveling wavelength decreased. Differential motion of the BM and IHCsc was observed in the second turn as the stimulus frequency increased toward CF. The longitudinal coupling measured in this study was longer than observed in previous studies. In summary the results suggest that the shape of the wave patterns present on the BM are not sufficient to characterize the displacement of the IHCsc.

Review article: Has the implementation of time-based targets for emergency department length of stay influenced the quality of care for patients? A systematic review of quantitative literature.

Time-based targets (TBTs) for ED stays were introduced to improve quality of care but criticised as having harmful unintended consequences. The aim of the review was to determine whether implementation of TBTs influenced quality of care. Structured searches in medical databases were undertaken (2000-2019). Studies describing a state, regional or national TBTs that reported processes or outcomes of care related to the target were included. Harvest plots were used to summarise the evidence. Thirty-three studies (n = 34 million) were included. In some settings, reductions in mortality were seen in ED, in hospital and at 30 days, while in other settings mortality was unchanged. Mortality reductions were seen in the face of increasing age and acuity of presentations, when short-stay admissions were excluded, and when pre-target temporal trends were accounted for. ED crowding, time to assessment and admission times reduced. Fewer patients left prior to completing their care and fewer patients re-presented to EDs. Short-stay admissions and re-admissions to wards within 30 days increased. There was conflicting evidence regarding hospital occupancy and ward medical emergency calls, while times to treatment for individual conditions did not change. The evidence for associations was mostly low certainty and confidence in the findings is accordingly low. Quality of care generally improved after targets were introduced and when compliance with targets was high. This depended on how targets were implemented at individual sites or within jurisdictions, with important implications for policy makers, health managers and clinicians.

Review article: Emergency department crowding measures associations with quality of care: A systematic review.

ED crowding has been reported to reduce the quality of care. There are many proposed crowding metrics, but the metric most strongly associated with care quality remains unknown. The present study aims to determine the crowding metric with the strongest links with processes and outcomes of care linked to the Institute of Medicine quality domains. Systematic searches in healthcare databases were conducted using terms for 'crowding', 'metrics' and 'performance', supplemented by grey literature and citation searches. The level of evidence for each association was assessed using an explicit tool. The body of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Evidence was synthesised using harvest plots. Titles and abstracts of 2052 studies were screened, 452 selected for full-text review and 183 included. Inter-observer agreement was moderate κ = 0.54 (95% confidence interval 0.50-0.59). Two thirds were from urban tertiary hospitals in North America (65%), Australasia (13%), Europe (12%) and Asia (8%). One third provided Level 3 or higher evidence. Metrics were based on occupancy (38%), time (31%), workload (19%) or combinations (9%). Data were synthesised from 25 607 375 patients, 2368 staff, 9089 hospitals and 101 177 sampling times. Almost all crowding metrics were patient-centred and reflect timeliness and efficiency. ED length of stay, boarding time and total occupancy had the strongest association with safety and effectiveness of care. ED length of stay was also associated with equity. The certainty of evidence for associations between crowding measures varied across domains of quality, from very low to moderate certainty.

An emergency department optimized protocol for qualitative research to investigate care seeking by patients with non-urgent conditions.

AIM: To describe a tailored qualitative research methodology for exploring the complex interaction of factors driving non-urgent care seeking in the emergency department. DESIGN: Qualitative descriptive design with a literature informed semi-structured interview and analysis structure. Triangulation with the State-Trait Anxiety Inventory allows expedited exploration of biopsychosocial factors. Consolidated criteria for reporting qualitative research requirements integrated. METHODS: With a short 10- to 15-min interview and a low-inference analysis process, this methodology offers a structured way to explore the "go to ED" decision, to understand the patient perspective on their healthcare needs and feed into the development of suitable local services that meet patient healthcare needs. RESULTS: This methodology offers a structured way for clinician-researchers to explore the factors that influence patients seeking care in the emergency departments for non-urgent conditions that are specific to their local health service environment. The described methodology is accessible to novice qualitative researchers and includes the semi-structured interview, coding and analysis frameworks.

Review article: Have emergency department time-based targets influenced patient care? A systematic review of qualitative literature.

Time-based targets for ED length of stay were introduced in England in 2000, followed by the rest of the UK, Canada, Ireland, New Zealand, and Australia after ED crowding was associated with poor quality of care and increased mortality. This systematic review evaluates qualitative literature to see if ED time-based targets have influenced patient care quality. We included 13 studies from four countries, incorporating 617 interviews. We conclude that time-based targets have impacted on the quality of emergency patient care, both positively and negatively. Successful implementation depends on whole hospital resourcing and engagement with targets.

Impact of the Four-Hour Rule policy on emergency medical services delays in Australian EDs: a longitudinal cohort study.

INTRODUCTION: Delayed handover of emergency medical services (EMS) patients to EDs is a major issue with hospital crowding considered a primary cause. We explore the impact of the 4-hour rule (the Policy) in Australia, focusing on ambulance and ED delays. METHODS: EMS (ambulance), ED and hospital data of adult patients presenting to 14 EDs from 2002 to 2013 in three jurisdictions were linked. Interrupted time series 'Before-and-After' trend analysis was used for assessing the Policy's impact. Random effects meta-regression analysis was examined for associations between ambulance delays and Policy-associated ED intake, throughput and output changes. RESULTS: Before the Policy, the proportion of ED ambulances delayed increased between 1.1% and 1.7% per quarter across jurisdictions. After Policy introduction, Western Australia's increasing trend continued but Queensland decreased by 5.1% per quarter. In New South Wales, ambulance delay decreased 7.1% in the first quarter after Policy introduction. ED intake (triage delay) improved only in New South Wales and Queensland. Each 1% ambulance delay reduction was significantly associated with a 0.91% reduction in triage delay (p=0.014) but not ED length of stay ≤4 hours (p=0.307) or access-block/boarding (p=0.605) suggesting only partial improvement in ambulance delay overall. CONCLUSION: The Policy was associated with reduced ambulance delays over time in Queensland and only the immediate period in New South Wales. Associations may be due to local jurisdictional initiatives to improve ambulance performance. Strategies to alleviate ambulance delay may need to focus on the ED intake component. These should be re-examined with longer periods of post-Policy data.

Significance of the Microfluidic Flow Inside the Organ of Corti.

We study the vibration modes of a short section in the middle turn of the gerbil cochlea including both longitudinal and radial interstitial fluid spaces between the pillar cells (PC) and the sensory hair cells to determine the role of the interstitial fluid flow within the organ of corti (OoC). Three detailed finite element (FE) models of the cochlear short section (CSS) are studied. In model 1, the CSS is without fluids; model 2 includes the OoC fluid, but not the exterior scalae fluids; and model 3 is the CSS with both scalae and OoC fluids. We find that: (1) the fundamental mode shape of models 1 or 3 is similar to the classical basilar membrane (BM) bending mode that includes pivoting of the arch of corti, and hence determines the low frequency vibrational mode shape of the cochlea in the presence of the cochlear wave. (2) The fundamental mode shape of model 2 is characterized by a cross-sectional shape change similar to the passive response of the cochlea. This mode shape includes a tilting motion of the inner hair cell (IHC) region, a fluid motion within the tunnel of corti (ToC) in the radial direction and along the OoC, and a bulging motion of the reticular lamina (RL) above the outer hair cell (OHC). Each of these motions provides a plausible mode of excitation of the sensory hair cells. (3) The higher vibrational modes of model 1 are similar to the electrically evoked response within the OoC and suggests that the higher vibrational modes are responsible for the active response of the cochlea. We also observed that the fluid flow through the OoC interstitial space is significant, and the model comparison suggests that the OoC fluid contributes to the biphasic BM motion seen in electrical stimulation experiments. The effect of fluid viscosity on cilium deflection was assessed by performing a transient analysis to calculate the cilium shearing gain. The gain values are found to be within the range of experimentally measured values reported by Dallos et al. (1996, The Cochlea, Springer-Verlag, New York).

When a health policy cuts both ways: Impact of the National Emergency Access Target policy on staff and emergency department performance.

OBJECTIVE: To explore the impact of the Four-Hour Rule/National Emergency Access Target (4HR/NEAT) on staff and ED performance. METHODS: A mixed-methods study design was used to link performance data from 16 participating hospitals with the experiences reported by 119 ED staff during policy implementation. Quantitative and qualitative measures were triangulated to identify the staff and organisational effects on hospital performance. An overall score was developed to categorise hospitals into: high, moderate and low performers, then compared with four qualitative themes: social factors, ED management, ED outcomes and 4HR/NEAT compliance. RESULTS: Key factors identified were stress and morale; intergroup dynamics; interaction with patients; resource management; education and training; financial incentives; impact on quality and safety; perceived improvements on access block and overcrowding. High performing hospitals reported increased stress and decreased morale, decreased staff-patient communication and staff shortages; significant changes in ED management and effective use of the whole-of-hospital approach. Moderate performing hospitals reported similar characteristics to a lesser degree, and the perception that 4HR/NEAT did not impact ED practice. Low performing hospitals also reported increased stress and low morale and a less effective whole-of-hospital approach. ED staff also reported a reduction in communication with patients. CONCLUSIONS: There was strong evidence of an association between high stress and low morale and the implementation of the 4HR/NEAT across all levels of performance. These adverse consequences of the 4HR/NEAT implementation indicate that a more nuanced approach to efficiency improvements is required. This would balance processes measured by 4HR/NEAT against a range of other clinical and organisational performance measures.

Perceptions and experiences of emergency department staff during the implementation of the four-hour rule/national emergency access target policy in Australia: a qualitative social dynamic perspective.

BACKGROUND: The Four-Hour Rule or National Emergency Access Target policy (4HR/NEAT) was implemented by Australian State and Federal Governments between 2009 and 2014 to address increased demand, overcrowding and access block (boarding) in Emergency Departments (EDs). This qualitative study aimed to assess the impact of 4HR/NEAT on ED staff attitudes and perceptions. This article is part of a series of manuscripts reporting the results of this project. METHODS: The methodology has been published in this journal. As discussed in the methods paper, we interviewed 119 participants from 16 EDs across New South Wales (NSW), Queensland (QLD), Western Australia (WA) and the Australian Capital Territory (ACT), in 2015-2016. Interviews were recorded, transcribed, imported to NVivo 11 and analysed using content and thematic analysis. RESULTS: Three key themes emerged: Stress and morale, Intergroup dynamics, and Interaction with patients. These provided insight into the psycho-social dimensions and organisational structure of EDs at the individual, peer-to-peer, inter-departmental, and staff-patient levels. CONCLUSION: Findings provide information on the social interactions associated with the introduction of the 4HR/NEAT policy and the intended and unintended consequences of its implementation across Australia. These themes allowed us to develop several hypotheses about the driving forces behind the social impact of this policy on ED staff and will allow for development of interventions that are rooted in the rich context of the staff's experiences.

Burden of primary care-type emergency department presentations using clinical assessment by general practitioners: A cross-sectional study.

OBJECTIVE: To compare methods of assessment of the burden of primary care-type ED (PCTED) presentations against clinical assessment by general practitioners (GPs) in ED. METHODS: A cross-sectional study involving clinical assessment of patients presenting to four EDs in Western Australia. The GPs assessed patients who were likely to be discharged home from ED, and considered whether they could be managed in general practice. Patient presentations were defined by the GPs as: PCTED; PCTED if additional primary care resources were available; or not PCTED. RESULTS: GP researchers determined that 80% of patients assessed were PCTED presentations, with one-third of these considered PCTED presentations if additional resources were available. A high proportion of identified PCTED presentations included categories excluded by previous methods. Analysis of linked data found the cohort assessed to be of lower urgency, younger, and with a shorter length of stay than the average patient being discharged from ED. After accounting for potential bias, it is suggested that 20-40% of all ED presentations could be PCTED presentations. CONCLUSIONS: Previous methods determining the burden of PCTED presentations have not been validated. Many presentations excluded by previous methods were identified as manageable in general practice by GPs clinically assessing patients in ED. Improved validation of criteria used to identify PCTED presentations will enable appropriately designed interventions to reduce such events.

Qualitative analysis of perceptions and experiences of emergency department staff in relation to implementation and outcomes of the Four-Hour Rule/National Emergency Access Target in Australia.

OBJECTIVE: The implementation of the time target policy (Four-Hour Rule/National Emergency Access Target [4HR/NEAT]) constituted a major change for ED, and potentially on quality of care. The present study aimed to understand perceptions and experiences of ED staff during 4HR/NEAT implementation. METHODS: A semi-structured interview was used to explore views and perceptions of 119 ED staff from 16 EDs in New South Wales, Australian Capital Territory, Queensland and Western Australia. The interviews covered aspects such as perceived changes in quality of clinical care, whether the capacity to deliver education was diminished or enhanced and whether the policy affected access to care. Interviews were transcribed, imported to NVivo 11 and analysed using content and thematic analysis. RESULTS: Three themes were identified: quality and safety of care; access block and overcrowding; and medical education and training. Participants described both positive and negative aspects of the policy. Although some reported negative impacts on care quality and access block, more cited overall improvements in these areas. The majority perceived that medical education and training was negatively affected, mainly because of restricted training opportunities and reduced time for procedural skills. CONCLUSIONS: ED staff perceived important effects on quality and safety of care; access block and overcrowding; and medical education and training. In relation to an optimised ED role, quality of care and access block were overall felt to be improved, while education and training deteriorated. Our study increases understanding of the complexity of policy implementation processes and its impact on staff. Staff perceptions are a valuable measure of system performance and should be incorporated into system change evaluations.

Impact of the Four-Hour Rule/National Emergency Access Target policy implementation on emergency department staff: A qualitative perspective of emergency department management changes.

OBJECTIVE: It has been 10 years since the ACEM Access Block Solutions Summit and 5 years since the introduction of the Four-Hour Rule/National Emergency Access Target (4HR/NEAT) policy. The impact of this policy on ED management and on ED staff has been poorly understood. The aim of the present study was to identify changes in ED management resulting from the policy based on ED staff experiences. METHODS: Semi-structured interviews were conducted and transcribed, imported to NVivo 11 and analysed using a combination of content, thematic analysis and phenomenological focus within a theoretical framework known as the 'logic model'. RESULTS: One hundred and nineteen ED staff participated in 2015-2016 to assess the impact of the policy implementation. Participants were drawn from 16 EDs in New South Wales, Queensland, Western Australia and Australian Capital Territory. In relation to ED management, three themes were identified: changes in ED management; activities and changes driven by the hospital in relation to 4HR/NEAT; and participant experiences in relation to policy compliance by staff. CONCLUSIONS: Policy implementation is a complex process that had both positive and negative consequences on how ED staff managed the implementation of the 4HR/NEAT policy and how it changed their work environment. Understanding the perceptions of staff involved in policy implementation has significance for the design of future implementation strategies. The biggest insight from the present study is that ED management is very complex and the policy generated multiple positive and negative changes demonstrating the wide range of processes involved in this area of health services research.

Impact of the National Emergency Access Target policy on emergency departments' performance: A time-trend analysis for New South Wales, Australian Capital Territory and Queensland.

OBJECTIVE: To evaluate the impact of the Australian National Emergency Access Target (NEAT) policy introduced in 2012 on ED performance. METHODS: A longitudinal cohort study of NEAT implementation using linked data, for 12 EDs across New South Wales (NSW), Australian Capital Territory (ACT) and Queensland (QLD) between 2008 and 2013. Segmented regression in a multi-level model was used to analyse ED performance over time before and after NEAT introduction. The main outcomes measures were ED length of stay ≤4 h, access block, number of ED presentations, short-stay admission (≤24 h), >24 h admissions, unplanned ED re-attendances within 7 days and 'left at own risk' (including 'did not wait for assessment'). RESULTS: Two years after NEAT introduction, ED length of stay ≤4 h increased in NSW and QLD (odds ratio [OR] = 2.48 and 3.24; P < 0.001) and access block decreased (OR = 0.41 and 0.22; P < 0.001), but not in ACT (OR = 1.28; P > 0.05). ED presentations increased over time before and after NEAT introduction with a significant increase above the projected trend in NSW after NEAT (mean ratio = 1.07). Short-stay admissions increased in QLD (OR = 2.60), ACT (OR = 1.68) and NSW (OR = 1.35). Unplanned ED re-attendances did not change significantly. Those who left at their own risk decreased significantly in NSW and QLD (OR = 0.38 and 0.67). CONCLUSION: ED presentations continued to increase over time in all jurisdictions. NSW and QLD, but not ACT, showed significant improvements in time-based measures. Significant increases in short-stay admissions suggest a strategic change in ED process associated with NEAT implementation. Rates of unplanned ED re-attendances and those leaving at their own risk showed no evidence for adverse effects from NEAT.

Impact of the four-hour National Emergency Access Target on 30 day mortality, access block and chronic emergency department overcrowding in Australian emergency departments.

OBJECTIVE: Previous research reported strong associations between ED overcrowding and mortality. We assessed the effect of the Four-Hour Rule (4HR) intervention (Western Australia (WA) 2009), then nationally rolled out as the National Emergency Access Target (Australia 2012) policy on mortality and patient flow. METHODS: A longitudinal cohort study of a population-wide 4HR, for 16 hospitals across WA, New South Wales (NSW), Australian Capital Territory (ACT) and Queensland (QLD). Mortality trends were analysed for 2-4 years before and after 4HR using interrupted time series technique. Main outcomes included the effect of 4HR on patient flow markers; admitted 30 day mortality trends; and patient flow marker performance during the study period. RESULTS: There were 40 281 deaths from 952 726 emergency admissions. All jurisdictions, except ACT, had improved flow and access block after 4HR. Age-standardised mortality was decreasing before the intervention. Post-intervention, WA had a significant reduction in mortality rate of -0.28 per 1000 patients per quarter (P = 0.040) while QLD had mixed results and NSW/ACT trends did not change significantly. Meta-regression of aggregated data for hospitals grouped on flow performances did not show significant mortality changes associated with the policy. CONCLUSIONS: The 4HR was introduced as a means of driving hospital performance by applying a time target. Patient flow improved, but the evidence for mortality benefit is controversial with improvement only in WA. Further research with more representative data from a larger number of hospitals over a longer time across Australia is needed to increase statistical power to detect long-term effects of the policy.

A model and experimental approach to the middle ear transfer function related to hearing in the humpback whale (Megaptera novaeangliae).

At present, there are no direct measures of hearing for any baleen whale (Mysticeti). The most viable alternative to in vivo approaches to simulate the audiogram is through modeling outer, middle, and inner ear functions based on the anatomy and material properties of each component. This paper describes a finite element model of the middle ear for the humpback whale (Megaptera novaeangliae) to calculate the middle ear transfer function (METF) to determine acoustic energy transmission to the cochlea. The model was developed based on high resolution computed tomography imaging and direct anatomical measurements of the middle ear components for this mysticete species. Mechanical properties for the middle ear tissues were determined from experimental measurements and published values. The METF for the humpback whale predicted a better frequency range between approximately 15 Hz and 3 kHz or between 200 Hz and 9 kHz based on two potential stimulation locations. Experimental measures of the ossicular chain, tympanic membrane, and tympanic bone velocities showed frequency response characteristics consistent with the model. The predicted best sensitivity hearing ranges match well with known vocalizations of this species.