Etranacogene dezaparvovec gene therapy for haemophilia B (HOPE-B): 24-month post-hoc efficacy and safety data from a single-arm, multicentre, phase 3 trial.

BACKGROUND: Etranacogene dezaparvovec, the first gene therapy approved for haemophilia B treatment, was shown to be superior to treatment with continuous prophylactic factor IX in terms of bleeding protection 18 months after gene therapy in a phase 3 trial. We report post-hoc 24-month efficacy and safety data from this trial to evaluate the longer-term effects of etranacogene dezaparvovec in individuals with haemophilia B. METHODS: The phase 3 HOPE-B trial enrolled males aged 18 years or older with inherited haemophilia B, classified as severe (plasma factor IX activity level <1%) or moderately severe (plasma factor IX activity level ≥1% and ≤2%), with a severe bleeding phenotype and who were on stable continuous factor IX prophylaxis. Participants were treated with a single infusion of etranacogene dezaparvovec (2 × 1013 genome copies per kg of bodyweight). The primary endpoint, reported previously, was non-inferiority of the annualised bleeding rate (ABR) during the 52 weeks following stable factor IX expression (defined as months 7-18 after treatment) versus an at least 6-month lead-in period in which participants received their usual continuous factor IX prophylaxis, and is updated here up to month 24. Additional, post-hoc efficacy analyses, including adjusted ABR, factor IX activity, participants within factor IX ranges, and factor IX use, and safety analyses were performed at 24 months after gene therapy. Data were analysed in the full analysis set, which comprised the 54 patients who received at least a partial dose of gene therapy. The trial is ongoing and is registered with ClinicalTrials.gov, number NCT03569891. FINDINGS: The study began on June 27, 2018, and participants were treated between January, 2019, and March, 2020; the date of data cutoff was April 21, 2022. 54 adult males (40 White, two Asian, one Black or African American, 11 other or missing) received a single intravenous infusion of etranacogene dezaparvovec and were followed for a median of 26·51 months (IQR 24·54-27·99), after a lead-in period of 7·13 months (6·51-7·82). In the updated analysis comparing months 7-24 after gene therapy to the lead-in period, mean adjusted ABR significantly reduced from 4·18 to 1·51 (p=0·0002) for all bleeds and from 3·65 to 0·99 (p=0·0001) for factor IX-treated bleeds. During each 6-month period after gene therapy, at least 67% of participants experienced no bleeding (36 of 54 during months 0-6 and stable thereafter), compared with 14 (26%) of 54 during the lead-in period. 24 months after gene therapy, 1 (2%) participant had one-stage factor IX activity less than 5%, whereas 18 (33%) had factor IX activity more than 40% (non-haemophilia range), with mean factor IX activity stable and sustained at 36·7% (SD 19·0%). 52 (96%) of 54 participants expressed endogenous factor IX, remaining free of factor IX prophylaxis at month 24. No new safety concerns were identified and no treatment-related serious adverse events or treatment-related deaths occurred. The most common treatment-related adverse events were an increase in alanine aminotransferase (nine [17%] of 54 patients), headache (eight [15%]), influenza-like illness (seven [13%]), and an increase in aspartate aminotransferase (five [9%]). INTERPRETATION: By providing durable disease correction throughout the 24 months after gene therapy, etranacogene dezaparvovec provides a safe and effective therapeutic option for patients with severe or moderately severe haemophilia B. FUNDING: uniQure and CSL Behring.

Aggregated Tau Measured by Visual Interpretation of Flortaucipir Positron Emission Tomography and the Associated Risk of Clinical Progression of Mild Cognitive Impairment and Alzheimer Disease: Results From 2 Phase III Clinical Trials.

Importance: Flortaucipir positron emission tomography (PET) scans, rated with a novel, US Food and Drug Administration-approved, clinically applicable visual interpretation method, provide valuable information regarding near-term clinical progression of patients with Alzheimer disease (AD) or mild cognitive impairment (MCI). Objective: To evaluate the association between flortaucipir PET visual interpretation and patients' near-term clinical progression. Design/Setting/Participants: Two prospective, open-label, longitudinal studies were conducted from December 2014 to September 2019. Study 1 screened 298 patients and enrolled 160 participants who had a flortaucipir scan at baseline visit. Study 2 selected 205 participants from the AMARANTH trial, which was terminated after futility analysis. Out of the 2218 AMARANTH participants, 424 had a flortaucipir scan around randomization, but 219 did not complete 18-month clinical dementia rating (CDR) assessments and thus were excluded. In both studies, all participants were diagnosed as clinically impaired, and they were longitudinally followed up for approximately 18 months after baseline. Main Outcomes and Measures: Flortaucipir scans were rated as either advanced or nonadvanced AD pattern using a predetermined visual interpretation method. The CDR sum of box (CDR-SB) score was used as primary clinical end point measurement in both studies. Results: Of the 364 study participants who had readable scans, 48% were female (n = 174 of 364), and the mean (SD) age was 71.8 (8.7) years. Two hundred forty participants were rated as having an advanced AD pattern. At 18 months follow-up, 70% of those with an advanced AD pattern (n = 147 of 210) had 1 point or more increase in CDR-SB, an event predefined as clinically meaningful deterioration. In contrast, only 46% of those with a nonadvanced AD pattern scan (n = 48 of 105) experienced the same event (risk ratio [RR], 1.40; 95% CI, 1.11-1.76; P = .005). The adjusted mean CDR-SB changes were 2.28 and 0.98 for advanced and nonadvanced AD pattern groups, respectively (P < .001). Analyses with other clinical end point assessments, as well as analyses with each individual study's data, consistently indicated a higher risk of clinical deterioration associated with an advanced AD scan pattern. Conclusions and Relevance: These results suggest that flortaucipir PET scans, when interpreted with an US Food and Drug Administration-approved, clinically applicable visual interpretation method, may provide valuable information regarding the risk of clinical deterioration over 18 months among patients with AD and MCI. Trial Registration: ClinicalTrials.gov Identifier: NCT02016560 and NCT03901105.

A multicentre longitudinal study of flortaucipir (18F) in normal ageing, mild cognitive impairment and Alzheimer's disease dementia.

The advent of tau-targeted PET tracers such as flortaucipir (18F) (flortaucipir, also known as 18F-AV-1451 or 18F-T807) have made it possible to investigate the sequence of development of tau in relationship to age, amyloid-ß, and to the development of cognitive impairment due to Alzheimer's disease. Here we report a multicentre longitudinal evaluation of the relationships between baseline tau, tau change and cognitive change, using flortaucipir PET imaging. A total of 202 participants 50 years old or older, including 57 cognitively normal subjects, 97 clinically defined mild cognitive impairment and 48 possible or probable Alzheimer's disease dementia patients, received flortaucipir PET scans of 20 min in duration beginning 80 min after intravenous administration of 370 MBq flortaucipir (18F). On separate days, subjects also received florbetapir amyloid PET imaging, and underwent a neuropsychological test battery. Follow-up flortaucipir scans and neuropsychological battery assessments were also performed at 9 and 18 months. Fifty-five amyloid-ß+ and 90 amyloid-ß- subjects completed the baseline and 18-month study visits and had valid quantifiable flortaucipir scans at both time points. There was a statistically significant increase in the global estimate of cortical tau burden as measured by standardized uptake value ratio (SUVr) from baseline to 18 months in amyloid-ß+ but not amyloid-ß- subjects (least squared mean change in flortaucipir SUVr : 0.0524 ± 0.0085, P < 0.0001 and 0.0007 ± 0.0024 P = 0.7850, respectively), and a significant association between magnitude of SUVr increase and baseline tau burden. Voxel-wise evaluations further suggested that the regional pattern of change in flortaucipir PET SUVr over the 18-month study period (i.e. which regions exhibited the greatest change) also varied as a function of baseline global estimate of tau burden. In subjects with lower global SUVr, temporal lobe regions showed the greatest flortaucipir retention, whereas in subjects with higher baseline SUVr, parietal and frontal regions were increasingly affected. Finally, baseline flortaucipir and change in flortaucipir SUVr were both significantly (P < 0.0001) associated with changes in cognitive performance. Taken together, these results provide a preliminary characterization of the longitudinal spread of tau in Alzheimer's disease and suggest that the amount and location of tau may have implications both for the spread of tau and the cognitive deterioration that may occur over an 18-month period.

Development of an imaging mitigation strategy for patient enrolment in the tanezumab nerve growth factor inhibitor (NGF-ab) program with a focus on eligibility assessment.

OBJECTIVE: Nerve growth factor antibodies (NGF-ab) have shown promising analgesic efficacy. Aim was to describe reader training efforts and present reliability data focusing on radiographic eligibility in the tanezumab program. METHODS: A multi-step process was used for reader calibration and reliability testing. First, a reference standard set of cases was created and diagnostic performance was evaluated. A second exercise focused on agreement of ordinal assessment (Kellgren-Lawrence grading) of radiographic osteoarthritis. Subsequently, 11 readers were trained and read a test set of 100 cases focused on eligibility assessments. Additional reliability testing and calibration of five core readers assessing eligibility of 30 cases was performed 3 and 6 months after study start. RESULTS: Sensitivity for the reference standard readings ranged from 0.50 to 0.90 and specificity from 0.40 to 0.83. Overall agreement for Kellgren-Lawrence grading ranged from 71.4% to 82.9%. For the 11 reader exercise, in 76% of cases at least 8 of 11 readers agreed on eligibility status. For the reliability testing 3 months after study start, in 80.0% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.43 (95% CI: 0.32-0.54). For the reliability testing after 6 months, in 83.3% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.52 (95% CI: 0.41-0.63). CONCLUSIONS: After intense efforts spent in the development of an imaging program for an NGF-ab clinical program, the achieved reliability for eligibility assessment is substantial but not perfect. Ongoing efforts of calibration prior to including additional readers to the program and during study conduct between current readers will be needed to ensure agreement on potential adverse events and radiographic disease severity.

Impact of lower body negative pressure induced hypovolemia on peripheral venous pressure waveform parameters in healthy volunteers.

Lower body negative pressure (LBNP) creates a reversible hypovolemia by sequestrating blood volume in the lower extremities. This study sought to examine the impact of central hypovolemia on peripheral venous pressure (PVP) waveforms in spontaneously breathing subjects. With IRB approval, 11 healthy subjects underwent progressive LBNP (baseline, -30, -75, and -90 mmHg or until the subject became symptomatic). Each was monitored for heart rate (HR), finger arterial blood pressure (BP), a chest respiratory band and PVP waveforms which are generated from a transduced upper extremity intravenous site. The first subject was excluded from PVP analysis because of technical errors in collecting the venous pressure waveform. PVP waveforms were analyzed to determine venous pulse pressure, mean venous pressure, pulse width, maximum and minimum slope (time domain analysis) together with cardiac and respiratory modulations (frequency domain analysis). No changes of significance were found in the arterial BP values at -30 mmHg LBNP, while there were significant reductions in the PVP waveforms time domain parameters (except for 50% width of the respiration induced modulations) together with modulation of the PVP waveform at the cardiac frequency but not at the respiratory frequency. As the LBNP progressed, arterial systolic BP, mean BP and pulse pressure, PVP parameters and PVP cardiac modulation decreased significantly, while diastolic BP and HR increased significantly. Changes in hemodynamic and PVP waveform parameters reached a maximum during the symptomatic phase. During the recovery phase, there was a significant reduction in HR together with a significant increase in HR variability, mean PVP and PVP cardiac modulation. Thus, in response to mild hypovolemia induced by LBNP, changes in cardiac modulation and other PVP waveform parameters identified hypovolemia before detectable hemodynamic changes.

Optimizing radiologist e-prescribing of CT oral contrast agent using a protocoling portal.

OBJECTIVE: The purpose of this study is to quantify the time expenditure associated with radiologist ordering of CT oral contrast media when using an integrated protocoling portal and to determine radiologists' perceptions of the ordering process. SUBJECTS AND METHODS: This prospective study was performed at a large academic tertiary care facility. Detailed timing information for CT inpatient oral contrast orders placed via the computerized physician order entry (CPOE) system was gathered over a 14-day period. Analyses evaluated the amount of physician time required for each component of the ordering process. Radiologists' perceptions of the ordering process were assessed by survey. Descriptive statistics and chi-square analysis were performed. RESULTS: A total of 96 oral contrast agent orders were placed by 13 radiologists during the study period. The average time necessary to create a protocol for each case was 40.4 seconds (average range by subject, 20.0-130.0 seconds; SD, 37.1 seconds), and the average total time to create and sign each contrast agent order was 27.2 seconds (range, 10.0-50.0 seconds; SD, 22.4 seconds). Overall, 52.5% (21/40) of survey respondents indicated that radiologist entry of oral contrast agent orders improved patient safety. A minority of respondents (15% [6/40]) indicated that contrast agent order entry was either very or extremely disruptive to workflow. CONCLUSION: Radiologist e-prescribing of CT oral contrast agents using CPOE can be embedded in a protocol workflow. Integration of health IT tools can help to optimize user acceptance and adoption.

Impact of central hypovolemia on photoplethysmographic waveform parameters in healthy volunteers part 2: frequency domain analysis.

OBJECTIVE: The photoplethysmographic (PPG) waveforms are modulated by the respiratory, cardiac and autonomic nervous system. Lower body negative pressure (LBNP) has been used as an experimental tool to simulate loss of central blood volume in humans. The aim of our research is to understanding PPG waveform changes during progressive hypovolemia. METHODS: With IRB approval, 11 volunteers underwent a LBNP protocol at baseline, 30, 75, and 90 mmHg (or until the subject became symptomatic). Subjects were monitored with finger and ear pulse oximeter probes, ECG, and finger arterial blood pressure monitor (FABP). Heart rate variability (HRV) was analyzed to high frequency (HRV-HF) (0.12-0.4 Hz) and low frequency (HRV-LF) (0.04-0.12 Hz). Frequency analysis of PPG waveforms were computed to low (0.04-0.11 Hz) frequency (PPG-LF), intermediate (0.12-0.18 Hz) frequency (PPG-IF), respiratory (0.19-0.3 Hz) frequency (PPG-Resp.) and cardiac (0.75-2.5 Hz) frequency (PPG-Cardiac)during different phases of LBNP protocol RESULTS: Heart rate increased significantly while systolic, mean and pulse pressure of the FABP declined slowly together with significant reductions in HRV-HF (0.12-0.4 Hz) and HRV-LF (0.04-0.12 Hz) power at LBNP(75). There was significant reduction in finger PPG-Cardiac modulation which is consistent with the reduction in the pulse pressure of the FABP. As the LBNP progress there was shift in the amplitude density of the ear PPG-Cardiac to PPG-Resp. Oscillation as an evidence of progressive hypovolemia with reduction in pulse pressure and increase in the respiratory induced variations. At LBNP(75), there were significant increased (>140% increase from the baseline) in ear PPG-IF (0.12-0.18 Hz) in the meantime HRV-HF showed significant reduction (>89%) from the baseline. At the symptomatic phase; there was a shift in ear PPG-IF to PPG-Resp. With an increase in the ear PPG-Resp. Modulation to ≥175% from the baseline CONCLUSION: The pulse oximeter waveform contains a complex mixture of the effect of cardiac, venous, autonomic, and respiratory systems on the central and peripheral circulation. The occurrence of autonomic modulation needs to be taken into account when studying signals that have their origins from central sites (e.g. ear and forehead).

Impact of central hypovolemia on photoplethysmographic waveform parameters in healthy volunteers. Part 1: time domain analysis.

INTRODUCTION: Our study sought to explore changes in photoplethysmographic (PPG) waveform param- eters, during lower body negative pressure (LBNP) which simulated hypovolemia, in spontaneously breathing volunteers. We hypothesize that during progressive LBNP; there will be a preservation of ear PPG parameters and a decrease in finger PPG parameters. METHODS: With IRB approval, 11 volunteers underwent a LBNP protocol at baseline, 30, 75, and 90 mm Hg (or until the subject became symptomatic). Subjects were monitored with finger and ear pulse oximeter probes, an ECG, and a finger arterial blood pressure monitor. The square root of the mean of the squared differences between adjacent NN intervals (RMSSD) which is the time domain analysis of the heart rate variability (HRV) was measured. PPG waveforms were analyzed for height, area, width 50, maximum and minimum slope. Data are presented as median and inter-quartile range. Friedman ANOVA and Wilcoxon tests were used to identify changes in hemo- dynamic and PPG parameters, P < 0.017 was considered statistically significant. RESULTS: There were no significant changes in the blood pressure variables at LBNP(30), but at and beyond LBNP(75), the decreases in systolic, mean and pulse pressure were significant as was the increase in diastolic pressure. Heart rate increased significantly at LBNP(30), reaching a maximum of 75.4% above baseline at the symptomatic phase while RMSSD showed significant reduction at LBNP(75). Finger PPG height, area, width 50, and maximum slope decreased significantly at LBNP(30) and during symptomatic phase they showed a reduction of 59.4, 76.9, 27.4 and 51.6%, respectively. Ear PPG height, area, width 50 and maximum slope did not change significantly until the LBNP(75), reached. During symptomatic phase, the respective declines reached 39.3, 61.0, 21.4 and 34.9%. CONCLUSION: PPG waveform parameters may prove to be sensitive and specific as early indicators of blood loss. These PPG changes were observed before profound decreases in arterial blood pressure. The relative sparing of central cutaneous blood flow is consistent with the increased parasympathetic innervation of central structures.

A novel approach using time-frequency analysis of pulse-oximeter data to detect progressive hypovolemia in spontaneously breathing healthy subjects.

Accurate and early detection of blood volume loss would greatly improve intraoperative and trauma care. This study has attempted to determine early diagnostic and quantitative markers for blood volume loss by analyzing photoplethysmogram (PPG) data from ear, finger and forehead sites with our high-resolution time-frequency spectral (TFS) technique in spontaneously breathing healthy subjects (n = 11) subjected to lower body negative pressure (LBNP). The instantaneous amplitude modulations present in heart rate (AM HR) and breathing rate (AMBR) band frequencies of PPG signals were calculated from the high-resolution TFS. Results suggested that the changes (P < 0.05) in AMBR and especially in AMHR values can be used to detect the blood volume loss at an early stage of 20% LBNP tolerance when compared to the baseline values. The mean percent decrease in AMHR values at 100% LBNP tolerance was 78.3%, 72.5%, and 33.9% for ear, finger, and forehead PPG signals, respectively. The mean percent increase in AMBR values at 100% LBNP tolerance was 99.4% and 19.6% for ear and finger sites, respectively; AMBR values were not attainable for forehead PPG signal. Even without baseline AMHR values, our results suggest that hypovolemia detection is possible with specificity and sensitivity greater than 90% for the ear and forehead locations when LBNP tolerance is 100%. Therefore, the TFS analysis of noninvasive PPG waveforms is promising for early diagnosis and quantification of hypovolemia at levels not identified by vital signs in spontaneously breathing subjects.

Tissue Doppler of early mitral filling correlates with simulated volume loss in healthy subjects.

OBJECTIVES: The accurate noninvasive assessment of preload in emergency department (ED) patients remains elusive. Point-of-care ultrasound (US) imaging, particularly evaluation of the inferior vena cava (IVC), has been shown to be qualitatively helpful. Doppler and tissue Doppler are now routinely available on ED US equipment, but few studies have looked at the correlation of dynamic changes in these parameters in a controlled model of hypovolemia. Our objective was to examine the correlation of Doppler parameters to simulated volume loss in healthy subjects using a lower-body negative pressure (LBNP) model and to compare these measurements to commonly used IVC measurements of preload. METHODS: Twelve paid volunteers with no known cardiovascular disease between the ages of 23 and 31 years old (mean ± SD = 25.5 ± 2.5 years old) were recruited. Hypovolemia was simulated using graduated LBNP levels with measurements taken at 0, -30, and -60 mm Hg and lower pressures as tolerated. Vital signs were monitored in all patients. US measurements recorded at each negative pressure level included IVC maximum (IVC(max)) and minimum (IVC(min)) dimensions; early (E) and late (A) transmitral filling velocities using pulsed-wave spectral Doppler; and early (E') and late (A') tissue Doppler velocities at the septal ((sep)) and lateral ((lat)) mitral annulus, using pulsed-wave tissue Doppler. RESULTS: Lower-body negative pressure correlated significantly and positively within subjects for all US parameters except for the A filling wave. E'(lat) and E'(sep) showed the strongest correlation with R² values of 0.749 (95% confidence interval [CI] = 0.577 to 0.854) and 0.738 (95% CI = 0.579 to 0.875) respectively, followed by A'(sep) 0.674 (95% CI = 0.416 to 0.845), IVC(max) 0.638 (95% CI = 0.425 to 0.806), A'(lat) 0.547 (95% CI = 0.280 to 0.802), IVC(min) 0.512 (95% CI = 0.192 to 0.777), and E 0.478 (95% CI = 0.187 to 0.762). Ratios correlated only moderately with LBNP level, including E/ E'(lat) R² of 0.430 (95% CI = 0.131 to 0.706), E/ E'(sep) 0.416 (95% CI = 0.183 to 0.686), and IVC collapsibility index (IVC(CI)) 0.201 (95% CI = 0.003 to 0.681). Vital signs, including heart rate and blood pressure, did not vary significantly with LBNP levels. CONCLUSIONS: In this pilot study of healthy subjects, tissue Doppler assessment of early diastolic filling correlated most strongly with simulated hypovolemia.

Can emergency medical dispatch systems safely reduce first-responder call volume?

OBJECTIVES: Emergency medical dispatch (EMD) protocols are intended to match response resources with patient needs. In a small city that previously sent a first-responder basic life support (BLS) engine company lights-and-siren response to every emergency medical services (EMS) call, regardless of nature or severity, an EMD system was implemented in order to reduce the number of such responses. The study objectives were to determine the effects of the EMD system on first-responder call volume and to assess the safety of the system. METHODS: This was a prospective, before-after trial. Using computer-assisted dispatch (CAD) records, all EMS calls in the 120 days before implementation of the EMD protocol and the 120 days after implementation were identified (excluding a one-month wash-in period). In the "after" phase, patient care reports of a random sample of cases in which an ambulance was dispatched with no first responders was manually reviewed to assess whether there might have been any benefit to first-responder dispatch. Given the lack of accepted clinical criteria for need for first responders, the investigators' clinical judgment was used. Paired t-tests were used to compare groups. RESULTS: There were 9,820 EMS calls in the "before" phase, with 8,278 first-responder engine runs (84.3%), and 9,943 EMS calls in the "after" phase, with 3,804 first-responder engine runs (39.1%). The first-responder companies were dispatched to a median of 5.65 runs/day (range 1.1-12.7) in the "before" phase, and 3.17 runs/day (range 0.6-5.0) in the "after" phase (p = 0.0008 by paired t-test). Review of 1,816 "after" phase ambulance-only patient care reports (PCRs) found ten (0.55%) in which first-responder dispatch might have been beneficial, but review of EMS and emergency department (ED) records found no adverse outcomes in these ten patients. CONCLUSIONS: This study suggests that a formal EMD system can reduce first-responder call volume by roughly one-half. The system appears to be safe for patients, with an undertriage rate of about one-half of one percent.

Direct intraosseous pressure monitoring of the femoral head during surgery for slipped capital femoral epiphysis.

Preventing avascular necrosis following surgical management of pediatric slipped capital femoral epiphysis is a critical goal. The direct intraosseous pressure monitor is a readily available and affordable technique that can easily be used by surgeons around the world.

Is there a role for first responders in EMS responses to medical facilities?

OBJECTIVE: Emergency medical dispatch (EMD) protocols should match response resources with patient needs. We tested a protocol sending only a commercial ambulance, without fire department first responders (FR), to all non-cardiac-arrest EMS calls at a physician-staffed HMO facility. Study objectives were to determine how often FR provided patient care at such facilities and whether EMD implementation could conserve FR resources without compromising patient care. METHODS: All EMS dispatches to this facility in the 4 months before implementation of the EMD protocol and 4 months after implementation were identified through dispatch records, and all FR and ambulance patient care reports were reviewed. In the "after" phase, all cases needing ALS transport were reviewed to examine whether there would have been benefit to FR dispatch. RESULTS: Of 242 dispatches in the "before" phase, BLS FR responded to 156 (64%), and ALS FR to 117 (48%). BLS FR provided patient care in 2 cases, and ALS FR in 17. Of 227 dispatches in the "after" phase, BLS FR responded to 10 (4%), and ALS FR to 10 (4%); all but one were protocol violations. BLS FR provided care in one case, and ALS FR in three. Review of the 93 "after" cases requiring ALS transport found none where FR presence would have been beneficial. CONCLUSIONS: First responders rarely provided patient care when responding to EMS calls at a physician-staffed medical facility. Implementation of an EMD protocol can safely reduce the number of FR responses to unscheduled ambulance calls at such a facility.