Red blood cell transfusion in surgery: an observational study of the trends in the USA from 2011 to 2016.

Guidelines recommend restrictive red blood cell transfusion strategies. We conducted an observational study to examine whether the rate of peri-operative red blood cell transfusion in the USA had declined during the period from 01 January 2011 to 31 December 2016. We included 4,273,168 patients from all surgical subspecialties. We examined parallel trends in rates of the following: pre-operative transfusion; prevalence of bleeding disorders and coagulopathy; and minimally invasive procedures. To account for changes in population and procedure characteristics, we performed multivariable logistic regression to assess whether the risk of receiving a transfusion had declined over the study period. Clinical outcomes included peri-operative myocardial infarction, stroke and all-cause mortality at 30 days. Peri-operative red blood cell transfusion rates declined from 37,040/441,255 (8.4%) in 2011 to 46,845/1,000,195 (4.6%) in 2016 (p < 0.001) across all subspecialties. Compared with 2011, the corresponding adjusted OR (95%CI) for red blood cell transfusion decreased gradually from 0.88 (0.86-0.90) in 2012 to 0.51 (0.50-0.51) in 2016 (p < 0.001). Pre-operative red blood cell transfusion rates and the prevalence of bleeding disorders decreased, whereas haematocrit levels and the proportion of minimally invasive procedures increased. Compared with 2011, the adjusted hazard ratios (95%CI) in 2012 and 2016 were 0.96 (0.90-1.02) and 1.05 (0.99-1.11) for myocardial infarction, 0.91 (0.83-0.99) and 0.99 (0.92-1.07) for stroke and 0.98 (0.94-1.02) and 0.99 (0.96-1.03) for all-cause mortality. Use of peri-operative red blood cell transfusion declined from 2011 to 2016. This was not associated with an increase in adverse clinical outcomes.

Molecular imaging of neuroinflammation in patients after mild traumatic brain injury: a longitudinal 123 I-CLINDE single photon emission computed tomography study.

BACKGROUND AND PURPOSE: Neuroinflammation has been proposed as part of the pathogenesis of post-concussion symptoms (PCS), but the inflammatory response of the human brain to mild traumatic brain injury (mTBI) remains unknown. We hypothesized that a neuroinflammatory response is present in mTBI at 1-2 weeks post-injury and persists in patients with PCS. METHODS: We scanned 14 patients with mTBI without signs of structural damage at 1-2 weeks and 3-4 months post-injury and 22 healthy controls once using the single photon emission computed tomography tracer 123 I-CLINDE, which visualizes translocator protein (TSPO), a protein upregulated in active immune cells. PCS was defined as three or more persisting symptoms from the Rivermead Post Concussion Symptoms Questionnaire at 3 months post-injury. RESULTS: Across brain regions, patients had significantly higher 123 I-CLINDE binding to TSPO than healthy controls, both at 1-2 weeks after the injury in all patients (P = 0.011) and at 3-4 months in the seven patients with PCS (P = 0.006) and in the six patients with good recovery (P = 0.018). When the nine brain regions were tested separately and results were corrected for multiple comparisons, no individual region differed significantly, but all estimated parameters indicated increased 123 I-CLINDE binding to TSPO, ranging from 2% to 19% in all patients at 1-2 weeks, 13% to 27% in patients with PCS at 3-4 months and -9% to 17% in patients with good recovery at 3-4 months. CONCLUSIONS: Neuroinflammation was present in mTBI at 1-2 weeks post-injury and persisted at 3-4 months post-injury with a tendency to be most pronounced in patients with PCS.

Helicopter vs. ground transportation of patients bound for primary percutaneous coronary intervention.

BACKGROUND: Implementation of the first Danish helicopter emergency medical service (HEMS) was associated with reduced time from first medical contact to treatment at a specialized centre for patients with suspected ST elevation myocardial infarction (STEMI). We aimed to investigate effects of HEMS on mortality and labour market affiliation in patients admitted for primary percutaneous coronary intervention (PCI). METHODS: In this prospective observational study, we included patients with suspected STEMI within the region covered by the HEMS from January 1, 2010, to April 30, 2013, transported by either HEMS or ground emergency medical services (GEMS) to the regional PCI centre. The primary outcome was 30-day mortality. RESULTS: Among the 384 HEMS and 1220 GEMS patients, time from diagnostic ECG to PCI centre arrival was lower with HEMS (median 71 min vs. 78 min with GEMS; P = 0.004). Thirty-day mortality was 5.0% and 6.2%, respectively (adjusted OR = 0.82, 95% CI 0.44-1.51, P = 0.52. Involuntary early retirement rates were 0.62 (HEMS) and 0.94 (GEMS) per 100 PYR (adjusted IRR = 0.68, 0.15-3.23, P = 0.63). The proportion of patients on social transfer payments longer than half of the follow-up time was 22.1% (HEMS) vs. 21.2% (adjusted OR = 1.10, 0.64-1.90, P = 0.73). CONCLUSION: In an observational study of patients with suspected STEMI in eastern Denmark, no significant beneficial effect of helicopter transport could be detected on mortality, premature labour market exit or work ability. Only a study with random allocation to one system vs. another, along with a large sample size, will allow determination of superiority of helicopter transport.

The effect of CT scanners in the trauma room - an observational study.

BACKGROUND: A CT scanner incorporated in the trauma resuscitation bay may benefit trauma patients by fastening work-up times; however, evidence in the area is still sparse. We assessed if time from admission to first CT scan was lower after incorporation of a CT scanner in the resuscitation bay. METHODS: We included trauma patients admitted in two 1-year periods, before and after a major rebuilding of the trauma room. Beforehand, one CT scanner was located in an adjacent room. After the rebuilding, two mobile CT scanners were placed in the resuscitation bays, where a moving gantry was combined with a trauma resuscitation table. Subgroup analyses were performed on severely injured and patients with traumatic brain injury. RESULTS: We included 784 patients before and 742 patients after the reconstruction. Case-mix differed between study periods as there was a higher proportion of severe injuries, traumatic brain injury and penetrating trauma in the after period. We found a minor increase in time to CT in the after period (20 vs. 21 min, P = 0.008). In a multivariate regression analysis adjusted for differences in case-mix and with time to CT as outcome, period was an insignificant explanatory variable [ß (before vs. after): 0.96 min 95% CI: 0.9-1.02, P = 0.3]. In both subgroups, we found no significant difference in time to CT. CONCLUSION: We found no reduction in time to CT scan, when comparing a period with mobile CT scanners incorporated in the resuscitation bay to an earlier period with a CT scanner next to the trauma room.

Quality of life following trauma before and after implementation of a physician-staffed helicopter.

BACKGROUND: Implementation of a physician-staffed helicopter emergency medical service (PS-HEMS) in Denmark was associated with lower 30-day mortality in severely injured trauma patients and less time on social subsidy. However, the reduced 30-day mortality in severely injured patients might be at the expense of a worse functional outcome and quality of life (QoL) in those who survive. The aim of this study was to investigate the effect of a physician-staffed helicopter on long-term QoL in trauma patients. METHODS: Prospective, observational study including trauma patients who survived at least 3 years after injury. A 5-month period prior to PS-HEMS implementation was compared with the first 12 months after PS-HEMS implementation. QoL was assessed 4.5 years after trauma by the SF-36 questionnaire. Primary endpoint was the Physical Component Summary score. RESULTS: Of the 1994 patients assessed by a trauma team, 1521 were eligible for inclusion in the study. Of these, 566 (37%) gave consent to participate and received a questionnaire by mail, and 402 (71%) of them returned the questionnaire (n = 114 before PS-HEMS; n = 288 after PS-HEMS implementation). Older patients, women and patients with trauma in the after PS-HEMS period were more likely to return the questionnaire. No significant association between QoL and period (before vs. after PS-HEMS) was found; the Physical Component Summary scores were 50.0 and 50.9 in the before and after PS-HEMS periods, respectively (P = 0.47). We also found no difference on multivariable analysis with adjustment for sex, age and injury severity score. CONCLUSION: No significant difference in QoL among trauma patients was found after implementation of a PS-HEMS.

Gait phenotype from mild cognitive impairment to moderate dementia: results from the GOOD initiative.

BACKGROUND AND PURPOSE: The differences in gait abnormalities from the earliest to the later stages of dementia and in the different subtypes of dementia have not been fully examined. This study aims to compare spatiotemporal gait parameters in cognitively healthy individuals, patients with amnestic mild cognitive impairment (MCI) and non-amnestic MCI, and patients with mild and moderate stages of Alzheimer's disease (AD) and non-Alzheimer's disease (non-AD). METHODS: Based on a cross-sectional design, 1719 participants (77.4 ± 7.3 years, 53.9% female) were recruited from cohorts from seven countries participating in the Gait, Cognition and Decline (GOOD) initiative. Mean values and coefficients of variation of spatiotemporal gait parameters were measured during normal pace walking with the GAITRite system at all sites. RESULTS: Performance of spatiotemporal gait parameters declined in parallel with the stage of cognitive decline from MCI status to moderate dementia. Gait parameters of patients with non-amnestic MCI were more disturbed compared to patients with amnestic MCI, and MCI subgroups performed better than demented patients. Patients with non-AD dementia had worse gait performance than those with AD dementia. This degradation of gait parameters was similar between mean values and coefficients of variation of spatiotemporal gait parameters in the earliest stages of cognitive decline, but different in the most advanced stages, especially in the non-AD subtypes. CONCLUSIONS: Spatiotemporal gait parameters were more disturbed in the advanced stages of dementia, and more affected in the non-AD dementias than in AD. These findings suggest that quantitative gait parameters could be used as a surrogate marker for improving the diagnosis of dementia.

Peri-operative cognitive dysfunction and protection.

Cognition may decline after surgery. Postoperative delirium, especially when hyperactive, may be easily recognised, whereas cognitive dysfunction is subtle and can only be detected using neuropsychological tests. The causes for these two conditions are largely unknown, although they share risk factors, the predominant one being age. Ignorance of the causes for postoperative cognitive dysfunction contributes to the difficulty of conducting interventional studies. Postoperative cognitive disorders are associated with increased mortality and permanent disability. Peri-operative interventions can reduce the rate of delirium in the elderly, but in spite of promising findings in animal experiments, no intervention reduces postoperative cognitive dysfunction in humans.

A prehospital use of ITClamp for haemostatic control and fixation of a chest tube.

We here present three cases in which a new device, the ITClamp Hemorrhage Control System (Innovative Trauma Care, Inc., Edmonton, Canada), was used for bleeding control and for securing a chest tube.

Is paediatric trauma severity overestimated at triage? An observational follow-up study.

BACKGROUND: Severe paediatric trauma is rare, and pre-hospital and local hospital personnel experience with injured children is often limited. We hypothesised that a higher proportion of paediatric trauma victims were taken to the regional trauma centre (TC). METHODS: This is an observational follow-up study that involves one level I TC and seven local hospitals. We included paediatric (< 16 years) and adult (≥ 16-≤ 79 years) trauma patients with a driving distance to the TC > 30 minutes. The primary end-point was the proportion of trauma patients arriving in the TC. RESULTS: We included 1934 trauma patients, 238 children and 1696 adults. A total of 33/238 children (13.9%) vs. 304/1696 adults (17.9%) were transported to the TC post-injury (P = 0.14). Among these, children were significantly less injured than adults [median Injury Severity Score (ISS) 9 vs. 14, P < 0.01]. There was no significant difference between the groups in the proportion of seriously injured trauma victims (ISS > 15) taken to the TC [8/11 (72.7%) vs. 139/182 (76.4%)]. The corresponding figures for ISS < 15 were 25/227 (11.0%) and 164/1509 (10.9%), respectively. No significant difference was found in intensive care unit length of stay or time to TC arrival. No paediatric vs. 36/1671 (2.2%) adult deaths were observed at 30-day follow-up (P = 0.03). CONCLUSIONS: There was no difference in the proportion of paediatric and adult trauma patients transported to the TC, neither overall nor among severely injured patients. Paediatric trauma patients admitted to the TC were, however, significantly less injured than adults.

Is postoperative cognitive dysfunction a risk factor for dementia? A cohort follow-up study.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is a common complication in elderly patients after major surgery. An association between POCD and the development of dementia has been suspected. In this study, we assessed if POCD was a risk factor for the occurrence of dementia. METHODS: Danish patients enrolled between November 1994 and October 2000 in the two International Studies of Postoperative Cognitive Dysfunction (ISPOCD 1 and 2) were followed until July 1, 2011. Cognitive performance was assessed at three time points: before operation, at 1 week, and 3 months after surgery, using a neuropsychological test battery. The time of (first) occurrence of dementia after surgery was assessed using the National Patient Register and the Psychiatric Central Research Register. Recorded dementia diagnoses (ICD-8 and ICD-10) were: Alzheimer's disease, vascular dementia, frontotemporal dementia, or dementia without specification. The risk of dementia according to POCD was assessed in the Cox regression models. RESULTS: A total of 686 patients with a median age of 67 [inter-quartile range (IQR) 61-74] yr were followed for a median of 11.1 (IQR 5.2-12.6) yr. Only 32 patients developed dementia during follow-up. The hazard ratio (95% CI) for any dementia diagnoses in patients with POCD at 1 week (n=118) and POCD at 3 months (n=57) after surgery compared with those without POCD was 1.16 (0.48-2.78), P=0.74, and 1.50 (0.51-4.44); P=0.47, respectively. CONCLUSIONS: POCD was not significantly associated with registered dementia over a median follow-up of 11 yr.

Impact of a physician-staffed helicopter on a regional trauma system: a prospective, controlled, observational study.

INTRODUCTION: This study aims to compare the trauma system before and after implementing a physician-staffed helicopter emergency medical service (PS-HEMS). Our hypothesis was that PS-HEMS would reduce time from injury to definitive care for severely injured patients. METHODS: This was a prospective, controlled, observational study, involving seven local hospitals and one level I trauma centre using a before and after design. All patients treated by a trauma team within a 5-month period (1 December 2009-30 April 2010) prior to and a 12-month period (1 May 2010-30 April 2011) after implementing a PS-HEMS were included. We compared time from dispatch of the first ground ambulance to arrival in the trauma centre for patients with Injury Severity Score (ISS) > 15. Secondary end points were the proportion of secondary transfers and 30-day mortality. RESULTS: We included 1788 patients, of which 204 had an ISS > 15. The PS-HEMS transported 44 severely injured directly to the trauma centre resulting in a reduction of secondary transfers from 50% before to 34% after implementation (P = 0.04). Median delay for definitive care for severely injured patients was 218 min before and 90 min after implementation (P < 0.01). The 30-day mortality was reduced from 29% (16/56) before to 14% (21/147) after PS-HEMS (P = 0.02). Logistic regression showed PS-HEMS had an odds ratio (OR) for survival of 6.9 compared with ground transport. CONCLUSIONS: Implementation of a PS-HEMS was associated with significant reduction in time to the trauma centre for severely injured patients. We also observed significantly reduced proportions of secondary transfers and 30-day mortality.

Why and how to implement an electronic resident's surgical logbook to improve operating-room training? First 5-year feedback from a French center.

INTRODUCTION: The evaluation of general surgery residents' operating room (OR)-training and technical skills progression may be difficult in the absence of a standardized evaluation tool. The aim of this study was to evaluate the impact of the implementation of an electronic "surgical logbook" for general surgery residents. METHODS: A prospective single center study was conducted between May 2015 and October 2020. An electronic logbook was filled by all residents immediately after each surgical procedure and data were prospectively collected and analyzed. RESULTS: Fifty-five students (34 men/21 women) reported their participation to 6917 surgical procedures, which corresponded to 55.5% of all procedures performed in our department. Residents performed the entire procedure as the operating surgeon in 28.5% of cases (n=1963), parts of the procedure as operating surgeon in 32.5% of cases (n=2230) and as operating-assistant in 38.5% (n=2672). Residents were more likely an operating surgeon for the entire procedure when they were assisted by a fellow or a practicing physician than an associate professor or a clinical professor (P<0.001). There was no significant difference in the major morbidity rate between different resident's contribution to the procedure (P=0.14). CONCLUSION: We present here a simple, useful and cost efficient tool which offers easy data collection and reporting that could help improve OR-training, OR-supervision and certification at a local or national level.

Pre-stroke socioeconomic status predicts upper limb motor recovery after inpatient neurorehabilitation.

BACKGROUND: Lower socioeconomic status (SES) is associated with higher mortality rates and the likelihood of receiving less evidence-based treatment after stroke. In contrast, little is known about the impact of SES on recovery after discharge from inpatient rehabilitation. The aim of this study was to investigate the influence of SES on long-term recovery after stroke. PATIENTS AND METHODS: In a prospective, observational, multicentre study, inpatients were recruited towards the end of rehabilitation. The 12-month follow-up focussed on upper limb motor recovery, measured by the Fugl-Meyer score. A clinically relevant improvement of ≥5.25 points was considered recovery. Patient-centric measures such as the Patient-reported Outcomes Measurement Information System-Physical Health (PROMIS-10 PH) provided secondary outcomes. Information on schooling, vocational training, income and occupational status pre-stroke entered a multidimensional SES index. Multivariate logistic regression models calculating odds ratios (ORs) and corresponding confidence intervals (CIs) were applied. SES was added to an initial model including age, sex and baseline neurological deficit. Additional exploratory analyses examined the association between SES and outpatient treatment. RESULTS: One hundred and seventy-six patients were enrolled of whom 98 had SES and long-term recovery data. Model comparisons showed the SES-model superior to the initial model (Akaike information criterion (AIC): 123 vs. 120, Pseudo R2: 0.09 vs. 0.13). The likelihood of motor recovery (OR = 17.12, 95%CI = 1.31; 224.18) and PROMIS-10 PH improvement (OR = 20.76, 95%CI = 1.28; 337.11) were significantly increased with higher SES, along with more frequent use of outpatient therapy (p = .02). CONCLUSIONS: Higher pre-stroke SES is associated with better long-term recovery after discharge from rehabilitation. Understanding these factors can improve outpatient long-term stroke care and lead to better recovery.KEY MESSAGEHigher pre-stroke socioeconomic status (SES) is associated with better long-term recovery after discharge from rehabilitation both in terms of motor function and self-reported health status.Higher SES is associated with significantly higher utilization of outpatient therapies.Discharge management of rehabilitation clinics should identify and address socioeconomic factors in order to detect individual needs and to improve outpatient recovery. Article registration: clinicaltrials.gov NCT04119479.

Depth of anaesthesia and post-operative cognitive dysfunction.

BACKGROUND: A deep level of anaesthesia measured by the bispectral index has been found to improve processing speed as one aspect of cognitive function after surgery. The purpose of the present study was to assess the possible effect of the level of anaesthesia on post-operative cognitive dysfunction (POCD) 1 week after surgery, as assessed by a neuropsychological test battery. METHODS: We included 70 patients >60 years of age scheduled for elective non-cardiac surgery with general anaesthesia. The depth of anaesthesia was monitored using the cerebral state monitor, which provided a cerebral state index (CSI) value. Cognitive function was assessed by the ISPOCD neuropsychological test battery before and at 1 week (or hospital discharge) after surgery and POCD was defined as a Z score above 1.96. RESULTS: Five patients were not assessed after surgery. The mean CSI was 40 and 43 in patients with (N=9) and without POCD (N=56), respectively (P=0.41). The cumulated time of both deep anaesthesia (CSI<40) and light anaesthesia (CSI>60) did not differ significantly, and no significant correlation was found between the mean CSI and the Z score. CONCLUSION: We were unable to detect a significant association between the depth of anaesthesia and the presence of POCD 1 week after the surgery.

[The usefulness of scores in the diagnosis of appendicitis]. / De l'intérêt des scores en matière de diagnostic d'appendicite.

The diagnosis of acute appendicitis relies largely on clinical experience; the performance of complementary tests is oftentimes unnecessary. We have created a score based on clinical and laboratory findings which can reliably categorize three zones of diagnostic probability : probable, doubtful, or improbable. Only the intermediate category requires complementary imaging. Alvarado first developed a scoring system based on operative findings and this has been modified and improved by others. In our experience, the scoring system of François has been most useful. This score is based on simple clinical data and findings such as age, sex, duration of symptoms, leucocytosis, palpable mass on rectal exam, and urinary symptoms. We have validated this score in a cohort of 202 patients presenting with right lower quadrant abdominal pain and found a sensitivity of 94.7% and a negative predictive value of 97.4% for patients falling into the probable and improbable categories. Management of patients with either very high or very low scores can proceed more expeditiously and with less expense. Diagnostic imaging can be reserved for those patients with intermediate scores where the diagnosis is in doubt. We have established a clinical pathway in our emergency department based on this scoring system.

Choice reaction time in patients with post-operative cognitive dysfunction.

BACKGROUND: Post-operative cognitive dysfunction (POCD) is detected by administration of a neuropsychological test battery. Reaction time testing is at present not included as a standard test. Choice reaction time (CRT) data from the first International Study of Post-operative Cognitive Dysfunction study were collected, but the association between POCD and reaction time has not been presented before. We hypothesized that CRT could be used as a screening tool for POCD. METHODS: Patients aged 60 years or older scheduled for major surgery with general anaesthesia were recruited from 13 centres in nine countries. CRT was measured 52 times using the four boxes test. Patients performed the test before surgery (n=1083), at 1 week (n=926) and at 3 months (n=852) post-operatively. CRT for the individual patient was determined as the median time of correct responses. The usefulness of the CRT as a screening tool for POCD was determined by the receiver-operator characteristic (ROC) curve. RESULTS: Patients with POCD 1 week after surgery had a significantly longer reaction time compared with patients without POCD: 857 (221) vs. 762 (201) ms, respectively (P<0.0001). Also at 3 months, patients with POCD had a significantly longer CRT. ROC curves revealed that a reaction time of 813 ms was the most appropriate cut-off at 1 week and 762 ms at 3 months but the positive predictive value for POCD was low: 34.4% and 14.7%, respectively. CONCLUSIONS: Post-operative cognitive dysfunction is associated with impaired performance in the CRT test but the test is a poor predictor of POCD.

Improved survival after an out-of-hospital cardiac arrest using new guidelines.

BACKGROUND: An out-of-hospital cardiac arrest (OHCA) is associated with a poor prognosis. We hypothesized that the implementations of 2005 European Resuscitation Council resuscitation guidelines were associated with improved 30-day survival after OHCA. METHODS: We prospectively recorded data on all patients with OHCA treated by the Mobile Emergency Care Unit of Copenhagen in two periods: 1 June 2004 until 31 August 2005 (before implementation) and 1 January 2006 until 31 March 2007 (after implementation), separated by a 4-month period in which the above-mentioned change took place. RESULTS: We found that 30-day survival increased after the implementation from 31/372 (8.3%) to 67/419 (16%), P=0.001. ROSC at hospital admission, as well as survival to hospital discharge, were obtained in a significantly higher proportion from 23.4% to 39.1%, P<0.0001, and from 7.9% to 16.3%, P=0.0004, respectively. Treatment after implementation was confirmed as a significant predictor of better 30-day survival in a logistic regression analysis. CONCLUSION: The implementation of new resuscitation guidelines was associated with improved 30-day survival after OHCA.

Indication for resuscitative thoracotomy in thoracic injuries-Adherence to the ATLS guidelines. A forensic autopsy based evaluation.

BACKGROUND: The appropriate indications for Resuscitative Thoracotomy (RT) are still debated in the literature and various guidelines have been proposed. This study aimed to evaluate whether Advanced Trauma Life Support (ATLS) guidelines for RT were applied correctly and to evaluate the proportion of deceased patients with potentially reversible thoracic lesions (PRTL). METHODS: The database at the Department of Forensic Medicine at Copenhagen University was queried for autopsy cases with thoracic lesions indicated by the SNOMED autopsy coding system. Patients were included if thoracic lesions were caused by a traumatic event with trauma team activation. Patient cases were blinded for any surgical intervention and evaluated independently by two reviewers for indications or contraindications for RT as determined by the ATLS guidelines. Second, autopsy reports were evaluated for the presence of PRTL. RESULTS: Sixty-seven patients met the inclusion criteria. Two were excluded due to insufficient data. The overall agreement with guidelines was 86% and 77% for blunt and penetrating trauma, respectively. For patients submitted to RT the overall agreement with guidelines was 63% being 45% and 74% for blunt and penetrating trauma, respectively. For patients who did not undergo RT the agreement with guidelines was 100%. In all cases where RT was performed in agreement between guidelines and the clinical decision the autopsy reports showed PRTL in 16 (84%) patients. In cases of non-agreement PRTL were found in 9 (82%) patients. CONCLUSIONS: Agreement with ATLS guidelines for RT was 63% for intervention and 100% for non-intervention in deceased patients with thoracic trauma. Agreement was higher for penetrating trauma than for blunt trauma. The adherence to guidelines did not improve the ability to predict autopsy findings of PRTL. Although the study has methodical limitations it represents a novel approach to the evaluation of the clinical use of RT guidelines.