Daytime, evening, and overnight: the 24-h radiology cycle and impact on interpretative accuracy

PURPOSE

To assess the influence of time of day when a study is interpreted on discrepancy rates for common and advanced studies performed in the acute community setting.

METHODS

This retrospective study used the databank of a U.S. teleradiology company to retrieve studies between 2012 and 2016 with a preliminary report followed by a final report by the on-site client hospital. Neuroradiology, abdominal radiology, and musculoskeletal radiology studies were included. Teleradiologists were fellowship trained in one of these subspecialty areas. Daytime, evening, and overnight times were defined. Associations between major and minor discrepancies, time of day, and whether the study was common or advanced were tested with significance set at p = .05.

RESULTS

A total of 5,883,980 studies were analyzed. There were 8444 major discrepancies (0.14%) and 17,208 minor discrepancies (0.29%). For common studies, daytime (0.13%) and evening (0.13%) had lower major discrepancy rates compared to overnight (0.14%) (daytime to overnight, RR = 0.57, 95%CI: 0.45, 0.72, p < 0.01 and evening to overnight, RR = 0.57, 95%CI: 0.49,0.67, p < 0.01). Minor discrepancy rates for common studies were decreased for evening (0.29%) compared to overnight (0.30%) (RR = 0.89, 95%CI: 0.80,0.99, p = 0.029). For advanced studies, daytime (.15%) had lower major discrepancy rates compared to evening (0.20%) and overnight (.23%) (daytime to evening, RR = 0.77, 95%CI: 0.61, 0.97, p = 0.028 and daytime to overnight, RR = 0.66, 95%CI: 0.50, 0.87, p ≤ 0.01).

CONCLUSION

Significantly higher major discrepancy rates for studies interpreted overnight suggest the need for radiologists to exercise greater caution when interpreting studies overnight and may require practice management strategies to help optimize overnight work conditions. The lower major discrepancy rates on advanced studies interpreted during the daytime suggest the need for reserving advanced studies for interpretation during the day when possible.

Time ratio disparities among ED patients undergoing head CT

PURPOSE

To assess if patients who underwent head computed tomography (CT) experienced disparities in the emergency department (ED) and if the indication for head CT affected disparities.

METHODS

This study employed a retrospective, IRB-approved cohort design encompassing four hospitals. All ED patients between January 2016 and September 2020 who underwent non-contrast head CTs were included. Furthermore, key time intervals including ED length of stay (LOS), ED assessment time, image acquisition time, and image interpretation time were calculated. Time ratio (TR) was used to compare these time intervals between the groups.

RESULTS

A total of 45,177 ED visits comprising 4730 trauma cases, 5475 altered mental status cases, 11,925 cases with head pain, and 23,047 cases with other indications were included. Females had significantly longer ED LOS, ED assessment time, and image acquisition time (TR = 1.012, 1.051, 1.018, respectively, P-value < 0.05). This disparity was more pronounced in female patients with head pain complaints compared to their male counterparts (TR = 1.036, 1.059, and 1.047, respectively, P-value < 0.05). Black patients experienced significantly longer ED LOS, image acquisition time, and image assessment time (TR = 1.226, 1.349, and 1.190, respectively, P-value < 0.05). These disparities persisted regardless of head CT indications. Furthermore, patients with Medicare/Medicaid insurance also faced longer wait times in all the time intervals (TR > 1, P-value < 0.001).

CONCLUSIONS

Wait times for ED head CT completion were longer for Black patients and Medicaid/Medicare insurance holders. Additionally, females experienced extended wait times, particularly when presented with head pain complaints. Our findings underscore the importance of exploring and addressing the contributing factors to ensure equitable and timely access to imaging services in the ED.

Contemporary Management of Blunt Liver Trauma: An Analysis of the Trauma Quality Improvement Program Registry (2007-19)

PURPOSE

To evaluate the effectiveness of management strategies for blunt liver injuries in adult patients.

MATERIALS AND METHODS

Patients 18 years and older with blunt liver injuries registered via the Trauma Quality Improvement Program (2007-19) were identified. Management strategies initiated within 24 hours of hospital presentation were classified as non-operative management (NOM), embolization, surgery, or combination therapy. Patients were stratified by injury grade. Linear models estimated each strategy's effect on hospital length of stay (LOS), intensive care unit (ICU) LOS, ventilator dependence, and mortality.

RESULTS

Of 78,127 included patients, 88.7%, 8.7%, 1.8%, and 0.8% of patients received NOM, surgery, embolization, and combination therapy, respectively. Among patients with low- (n = 62,237) and high-grade (n = 15,890) injuries and compared to all other management strategies, NOM was associated with the shortest hospital LOS and ICU LOS. Among patients with low-grade injuries and compared to surgery, embolization was associated with a shorter hospital LOS (9.7 days, P < .001, Cohen's d = .32) and ICU LOS (5.3 days, P < .001, Cohen's d = .36). Among patients with high-grade injuries and compared to surgery, embolization was associated with a shorter ICU LOS (6.0 days, P < .01, Cohen's d = .24). Among patients with low- and high-grade injuries and compared to embolization, surgery was associated with higher odds of mortality (P < .001).

CONCLUSIONS

Among patients presenting with blunt liver injuries and compared to surgery, embolization was associated with a shorter ICU LOS and lower risk of mortality.

Are disparities in emergency department imaging exacerbated during high-volume periods?

PURPOSE

Evaluate if disparities in the emergency department (ED) imaging timeline exist, and if disparities are altered during high volume periods which may stress resource availability.

METHODS

This retrospective study was conducted at a four-hospital healthcare system. All patients with at least one ED visit containing imaging from 1/1/2016 to 9/30/2020 were included. Peak hours were defined as ED encounters occurring between 5 pm and midnight, while all other ED encounters were non-peak hours. Patient-flow data points included ED length of stay (LOS), image acquisition time, and diagnostic image assessment time.

RESULTS

321,786 total ED visits consisted of 102,560 during peak hours and 219,226 during non-peak hours. Black patients experienced longer image acquisition and image assessment times across both time periods (TR = 1.030; p < 0.001 and TR = 1.112; p < 0.001, respectively); Black patients also had increased length of stay compared to White patients, which was amplified during peak hours. Likewise, patients with primary payer insurance experienced significantly longer image acquisition and image assessment times in both periods (TR > 1.00; p < 0.05 for all). Females had longer image acquisition and image assessment time and the difference was more pronounced in image acquisition time during both peak and non-peak hours (TR = 1.146 and TR = 1.139 respectively with p < 0.001 for both).

CONCLUSION

When measuring radiology time periods, patient flow throughout the ED was not uniform. There was unequal acceleration and deceleration of patient flow based on racial, gender, age, and insurance status. Segmentation of patient flow time periods may allow identification of causes of inequity such that disparities can be addressed with targeted actions.

Starting an Emergency Radiology Division: Scheduling and Staffing, Compensation, and Equity and Parity

Establishing an emergency radiology division in a practice that has long-standing patterns of operational routines comes with both challenges and opportunities. In this article, considerations around scheduling and staffing, compensation, and equity and parity are provided with supporting literature references. Furthermore, a panel of experts having established, grown and managed emergency radiology divisions in North America and Europe share their experiences through a question and answer format.

ACR Appropriateness Criteria® Myelopathy: 2021 Update

Myelopathy is a clinical diagnosis with localization of the neurological findings to the spinal cord, rather than the brain or the peripheral nervous system, and then to a particular segment of the spinal cord. Myelopathy can be the result of primary intrinsic disorders of the spinal cord or from secondary conditions, which result in extrinsic compression of the spinal cord. While the causes of myelopathy may be multiple, the acuity of presentation and symptom onset frame a practical approach to the differential diagnosis. Imaging plays a crucial role in the evaluation of myelopathy with MRI the preferred modality. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The Impact of Fatigue on Complex CT Case Interpretation by Radiology Residents

RATIONALE AND OBJECTIVES

To examine the effect of fatigue on diagnostic performance and interpretation of complex CT trauma studies by radiology residents.

MATERIALS AND METHODS

Ten 2nd, 3rd, and 4th year radiology residents were given 1 hour to review as many complex CT cases as they could, once when they were fresh and once when they were fatigued (after a full day or night of diagnostic reading activity). Number of cases completed, interpretation accuracy and time per case were analyzed.

RESULTS

On average readers completed 7.5 cases when fresh and 7.3 when fatigued, with 4th and 3rd year residents spending more time per case when fresh than fatigued and 2nd year residents spending more time when fatigued. The total number of true positives for major (fresh mean = 29.4 vs fatigued mean = 24.1) and minor (fresh mean = 23.30 vs fatigued mean = 18.90) findings decreased for fresh vs fatigued; and there was a significant difference as a function of year of residency (F = 4.72, p = 0.027). The 4th year residents had the most TPS in both conditions, followed by 3rd then 2nd year residents. There were more false positives when fatigued than fresh.

CONCLUSION

Fatigue significantly impacts radiologic diagnostic efficiency and efficacy, and differs as a function of year of residency.

Contemporary Management of Pediatric Blunt Splenic Trauma: A National Trauma Databank Analysis

PURPOSE

To quantify changes in the management of pediatric patients with isolated splenic injury from 2007 to 2015.

MATERIALS AND METHODS

Patients under 18 years old with registered splenic injury in the National Trauma Data Bank (2007-2015) were identified. Splenic injuries were categorized into 5 management types: nonoperative management (NOM), embolization, splenic repair, splenectomy, or a combination therapy. Linear mixed models accounting for confounding variables were used to examine the direct impact of management on length of stay (LOS), intensive care unit (ICU) days, and ventilator days.

RESULTS

Of included patients (n = 24,128), 90.3% (n = 21,789), 5.6% (n = 1,361), and 2.7% (n = 640) had NOM, splenectomy, and embolization, respectively. From 2007 to 2015, the rate of embolization increased from 1.5% to 3.5%, and the rate of splenectomy decreased from 6.9% to 4.4%. Combining injury grades, NOM was associated with the shortest LOS (5.1 days), ICU days (1.9 days), and ventilator days (0.5 day). Moreover, splenectomy was associated with longer LOS (10.1 days), ICU days (4.5 days), and ventilator days (2.1 days) than NOM. The average failure rate of NOM was 1.5% (180 failures/12,378 cases). Average embolization failure was 1.3% (6 failures/456 cases). Splenic artery embolization was associated with lower mortality than splenectomy (OR: 0.10, P <.001). No statistically significant difference was observed in mortality between embolization and NOM (OR: 0.96, P = 1.0).

CONCLUSIONS

In pediatric splenic injury, NOM is the most utilized and associated with favorable outcomes, most notably in grades III to V pediatric splenic injury. If intervention is needed, embolization is effective and increasingly utilized most significantly in lower grade injuries.

Using Point-of-Care Patient Photographs With Musculoskeletal Radiography to Identify Errors of Laterality in Emergency Department Imaging

PURPOSE

To evaluate the utility of point-of-care patient photographs accompanying musculoskeletal (MSK) radiography to identify errors in laterality.

MATERIALS AND METHODS

In this Institutional Review Board-approved study, 347 consecutive MSK radiograph-photograph combinations and corresponding radiography provider orders between October 1, 2018 and January 31, 2019, were retrospectively reviewed. Photographs were obtained simultaneously with the radiographs using the PatCam System (Camerad Technologies, Decatur, GA). In each case, laterality was recorded for all photographs, radiograph side markers, and radiography orders, and any laterality discrepancy among these variables was recorded. The side indicated on the provider order was taken as the gold standard.

RESULTS

Three hundred and forty-seven consecutive MSK radiograph-photograph combinations from 253 unique patients consisted of 129 upper extremity and 218 lower extremity radiographs. Two discrepancies (0.58%) in laterality were identified. The first discrepant case consisted of a left foot radiograph, which was labeled as "R" on the radiograph and left on the order. In this case, the patient photograph confirmed with certainty that the incorrect side marker was placed. The second discrepant case was a hip radiograph, in which 1 of 3 images had discrepant L/R labeling; the patient was covered with a sheet, both hips were included in the photograph, but a monitoring device on the patient's left side in the photograph also included on the radiographs determined which film was incorrectly labeled.

CONCLUSIONS

Patient photographs obtained concurrently with MSK radiographs can provide a valuable quality tool in identifying errors of laterality. In our study, over 1 in 200 patients was identified as having such an error.

Imaging review of sickle cell disease for the emergency radiologist

Sickle cell disease (SCD), one of the most common inherited genetic syndromes in the USA, is characterized by recurring episodes of acute illness and progressive multisystem organ injury. Individuals with SCD frequently present to the emergency department for a spectrum of complications, such as vaso-occlusive crises, infection, cholecystitis, and stroke. Imaging correlates for most of these presentations exist, positioning the emergency radiologist to play a pivotal role in facilitating patient care. Using a systems-based approach, we describe the acute and chronic imaging manifestations of SCD that an emergency radiologist can expect to encounter in most practice settings, highlighting the unique pathophysiology of this disorder that typically underlies the imaging findings.

The Effects of Fatigue From Overnight Shifts on Radiology Search Patterns and Diagnostic Performance

PURPOSE

The aim of this study was to assess the effect of overnight shifts (ONS) on radiologist fatigue, visual search pattern, and diagnostic performance.

METHODS

This experimental study was approved by the institutional review board. Twelve radiologists (five faculty members and seven residents) each completed two sessions: one during a normal workday ("not fatigued") and another in the morning after an ONS ("fatigued"). Each radiologist completed the Swedish Occupational Fatigue Inventory. During each session, radiologists viewed 20 bone radiographs consisting of normal and abnormal findings. Viewing time, diagnostic confidence, and eye-tracking data were recorded.

RESULTS

Swedish Occupational Fatigue Inventory results demonstrated worsening in all five variables (lack of energy, physical exertion, physical discomfort, lack of motivation, and sleepiness) after ONS (P < .01). Overall, participants demonstrated worse diagnostic performance in the fatigued versus not fatigued state (P < .05). Total viewing time per case was longer when fatigued (35.9 ± 25.8 seconds) than not fatigued (24.8 ± 16.3 seconds) (P < .0001). Total viewing time per case was longer for residents (P < .05). Mean total fixations generated during the search increased by 60% during fatigued sessions (P < .0001). Mean time to first fixate on the fracture increased by 34% during fatigued sessions (P < .0001) and was longer for residents (P < .01). Dwell times associated with true- and false-positive decisions increased, whereas those with false negatives decreased.

CONCLUSIONS

After ONS, radiologists were more fatigued with worse diagnostic performance, a 45% increase in view time per case, a 60% increase in total gaze fixations, and a 34% increase in time to fixate on the fracture. The effects of fatigue were more pronounced in residents.

Lipofibromatous Hamartoma of the Median Nerve: A Case Report

Lipofibromatous hamartoma is a rare and slow growing benign fibro-fatty tumor. It is characterized by the proliferation of mature adipocytes within the epineurium and the perineurium of the peripheral nerves. In the upper extremity, it most commonly affects the median nerve. Median nerve involvement commonly leads to pain, numbness, paresthesia and carpal tunnel syndrome. This article presents a case of lipofibromatous hamartoma in an 8-year-old child followed by a discussion of the epidemiology, diagnosis, imaging details and treatment options for this condition.

Creating and Sustaining a Successful Fellowship Program: Challenges and Solutions

Subspecialty expertise and fellowship training are two of the most desirable attributes in new radiology hires and, not surprisingly, the vast majority of diagnostic radiologists entering the job market today have had fellowship training. Fellowship training imparts not only expertise beyond that which is attainable during residency, but also a unique opportunity for professional maturation. In this article, we offer guidance in planning, building and sustaining a successful fellowship. The key steps in this process include strategic planning, development of a curriculum that can be customized to meet the educational goals of any individual fellow, professional development and trainee preparation for the marketplace, and approaches to ensure program longevity and success through local, regional and national fellow recruitment efforts. While many of the ideas presented are framed from the perspective of their integration into a newly formed fellowship program, they can also be adapted for use by existing fellowship programs as opportunities for program growth and improvement.

Amyand's Hernia: A Case Report

Amyand's hernia is a rare and atypical hernia characterized by the herniation of the appendix into the inguinal sac. This hernia may be present without symptoms until inflammation of the appendix may lead to incarceration, strangulation, necrosis, perforation or rupture. Early symptoms include tenderness and inguinal swelling which may be misdiagnosed as a strangulated hernia. This condition can be difficult to diagnose clinically. Ultrasound and Computed Tomography may aid in diagnosis. This article presents a rare case of Amyand's hernia followed by a discussion of the epidemiology, diagnosis, imaging details and treatment options for this condition.

Structured report compliance: effect on audio dictation time, report length, and total radiologist study time

The purpose of this study was to examine structured template use among emergency radiologists, and if this influences audio dictation time, radiology report length, or total radiologist study time. Retrospective data collection of consecutive occurrences of seven common imaging examinations interpreted by a dedicated emergency radiology division over a 2-month period yielded 3449 reports. Templates had been in place for >3 years. For each examination, we documented the individual audio dictation time (ADT), total words, and total time the radiologist spent on a study from report creation until final signing. In 81.2 % (n = 2772) of all cases, a basic template was used. In 2.8 % (n = 78) of these template-use cases, the radiologist removed key elements from the structured template. Of the 3417 reports with complete data, mean ADT was 37.3 s, mean word length was 132.3 (of which, on average, 64 were dictated), and total radiologist time per study (TRT) was 349.7 s. Study type was significantly associated with ADT, total words, and TRT (p < 0.001). Template usage decreased ADT (p < 0.001) by 47 %, but did not affect total word length or TRT. Parameters varied by individual attending (p < 0.001): 20 % (2/10) of attendings had differences in report length when using versus not using templates (p < 0.001). With long-term template usage, compliance with structured templates is high, and few radiologists significantly alter the templates. Template use decreases ADT and for a small fraction of radiologists impacts total word length and has a mixed impact on TRT.

Enteric Distribution of Oral Contrast in Emergency Department Patients Undergoing Abdominal-Pelvic Computed Tomography

PURPOSE

The study sought to assess the gastrointestinal (GI) distribution of oral contrast (OC) among emergency department (ED) patients and determine if contrast reaches the terminal ileum or site of pathology to assist in diagnosis.

METHODS

Retrospectively, adults undergoing abdominal-pelvic computed tomography (APCT) in the ED at 2 hospitals were identified over a 3-month period. APCTs were reviewed for location of OC. Presence, site, type of bowel pathology, and prior gastrointestinal surgery were documented. When applicable, the site of bowel pathology was evaluated for the presence or absence of OC.

RESULTS

There were 1349 exams with mean age 50.5 years (range 18-97 years), 41% male, with 530 (39%) receiving OC. In 271 of 530 (51%), OC reached the terminal ileum (TI). Bowel pathology was present in 31% of cases (165 of 530). When bowel pathology was present, 47% (77 of 165) had OC present at the pathology site. The GI tract was divided into 4 anatomic segments: OC most frequently reached pathology in stomach and duodenum (84%), but was present less frequently at sites of pathology from jejunum to TI (35%), proximal colon (57%), and distal colon (28%). In only 84 of 530 OC cases (16%) did contrast extend from the stomach to distal colon. OC administration contributed to longer mean APCT order to final report of 0.5 hours and longer mean ED length of stay of 0.8 hours compared with all patients who received APCT.

CONCLUSIONS

Optimal OC distribution is not achieved in more than half of ED patients, raising questions about the continued use of OC in the ED.

Incidental Findings on Bedside Ultrasonography: Detection Rate and Accuracy of Resident-Performed Examinations in the Acute Setting

Background

Bedside ultrasonography has become a valuable tool in the emergent care setting for triage and rapid evaluation of patients who are acutely ill. Given the cross-sectional nature of ultrasound technology, incidental findings are frequently encountered during imaging. These can impact clinical management and can pose a diagnostic dilemma for emergency medicine (EM) physicians and EM residents.

Purpose

Our retrospective study was designed to evaluate the prevalence and detection rate of incidental findings on bedside ultrasound examinations performed by EM residents. We also sought to identify types of incidental findings encountered and the diagnostic accuracy of those findings.

Materials and Methods

Board-certified radiologists retrospectively reviewed bedside ultrasonography examinations performed and interpreted by EM residents at a large urban academic hospital. Our sample included patients who presented with traumatic and nontraumatic symptoms in the acute setting. Findings were defined as incidental only if they were previously unknown and not related to a patients presenting symptoms. The results were corroborated with electronic medical records and additional pertinent imaging when available.

Results

Of 196 examinations analysed, EM residents identified incidental findings on 26% of the studies, which mostly involved the renal and biliary system. Radiologist review detected incidental findings in 20.9% but was more accurate when supplemental imaging was available. EM residents detected incidental findings at rates similar to that published previously and had moderate interobserver agreement with radiologist review. Worrisome and indeterminate findings were confirmed by additional work-up and further imaging.

Conclusion

Incidental findings are frequently encountered on bedside ultrasonography and have the potential to alter clinical management. Expertise in detection and knowledge of the presence and spectrum of these incidental findings is essential for appropriate triage, patient management, and follow-up.

Specific Radiological Findings of Traumatic Gastrointestinal Tract Injuries in Patients with Blunt Chest and Abdominal Trauma

Gastrointestinal hollow viscus injury after blunt chest and abdominal trauma is uncommon and complicates 0.6%-1.2% of all cases of trauma. Early recognition of such injuries significantly decreases morbidity and mortality. Since physical examination is not accurate in detecting such injuries, contrast-enhanced computed tomography has been the mainstay for diagnosis in many emergency departments. This pictorial essay aims to review the incidence, mechanisms, and signs of gastrointestinal hollow viscus injuries in the setting of blunt chest and abdominal trauma.

Association of lumbar fractures, abdominal aortic calcification, and osteopenia

PURPOSE

The purpose was to assess if abdominal aortic calcification (AAC) and low bone mineral density (BMD) are associated with fractures on lumbar spine radiographs in trauma patients.

METHODS

Retrospectively, 303 consecutive lumbar radiographs were independently reviewed by two radiologists for AAC, low BMD, and traumatic findings.

RESULTS

Thirty-one percent of patients had low BMD, 34% had AAC, and 24% had both. Eleven percent of radiographs showed traumatic findings. Seventy-six percent of positive cases had low BMD (P<.001), and 64% had AAC (P<.001).

CONCLUSION

A higher index of suspicion for fractures is warranted when AAC and low BMD are present.

Intra-abdominal Solid Organ Injuries: An Enhanced Management Algorithm

The organ injury scale grading system proposed by the American Association for the Surgery of Trauma provides guidelines for operative versus nonoperative management in solid organ injuries; however, major shortcomings of the American Association for the Surgery of Trauma injury scale may become apparent with low-grade injuries, in which conservative management may fail. Nonoperative management of common intra-abdominal solid organ injuries relies increasingly on computed tomographic findings and other clinical factors, including patient age, presence of concurrent injuries, and serial clinical assessments. Familiarity with characteristic imaging features is essential for the prompt diagnosis and appropriate treatment of blunt abdominal trauma. In this pictorial essay, the spectrum of the American Association for the Surgery of Trauma organ injury scale grading system is illustrated, and a multidisciplinary management algorithm for common intra-abdominal solid organ injuries is proposed.

Coronary anomalies encountered in the acute setting: an imaging review

A broad spectrum of congenital coronary anomalies may be discovered on imaging and sometimes in the emergency setting on computed tomography (CT). Most coronary artery anomalies are of academic interest; however, a minority can cause morbidity and mortality and symptoms such as angina, myocardial infarction, or arrhythmias. These anomalies are usually discovered as an incidental finding on CT examinations as part of the diagnostic workup for other pathology or on dedicated coronary computed tomography angiography (CCTA) as part of the evaluation for a coronary cause of chest pain. The purpose of this pictorial review is to demonstrate the types of coronary anomalies and to enhance the clinicians' understanding of the imaging classifications and clinical implications.

Small-bowel obstruction associated with Crohn's enterolith

One of the lesser known clinical manifestations of Crohn's disease is the formation of small-bowel enteroliths. These concretions precipitate in the setting of small-bowel stasis within the alimentary tract and are associated with a variety of disease states causing strictures or diverticula. In the acute setting, patients typically present with signs of intestinal obstruction due to stone impaction. The case we report involves a 67-year-old female with long-standing Crohn's disease who presented with a 6-day history of worsening abdominal pain. Plain abdominal radiographs demonstrated dilated bowel loops consistent with intestinal obstruction. Computed tomography revealed a 2.5-cm calcified density at the transition point in the distal ileum, and two additional stones were present in the proximal ileum. At surgery, multiple ileal strictures were found, and ileocolic resection with primary anastomoses was performed. The accurate diagnosis of enterolithiasis in the setting of Crohn's disease has significant clinical implications for management and is a harbinger of underlying bowel stenosis.

Changes in cerebral oximetry during peritoneal insufflation for laparoscopic procedures

Background:

Changes in cardiac output may occur during insufflation for laparoscopic procedures. However, there are limited data regarding its potential effects on cerebral oxygenation.

Materials and Methods:

Cerebral oxygenation (ScO₂), end tidal CO₂, heart rate, blood pressure and oxygen saturation by pulse oximetry were recorded every 5 minutes prior to insufflation, during insufflation and after desufflation. Minute ventilation was increased to maintain normocapnia and the depth of anesthesia was adjusted or fluids/phenylephrine administered to maintain the blood pressure within 20% of the baseline.

Results:

The cohort for the study included 70 adults for laparoscopic herniorrhaphy, gastric bypass or cholecystectomy. A total of 1004 ScO₂ values were obtained during laparoscopy. The ScO₂ decreased from the baseline in 758 of the 1004 data points. The ScO₂ was 0–9 less than the baseline in 47.8% of the values, 10–19 less than the baseline in 24.9% of the values and 20–29 less than the baseline in 26 values (2.6%). Eighty-two (8.2%) of the values were less than 80% of the baseline value, while 25 values (2.5%) were less than 75% of the baseline value. Twelve patients had at least one ScO₂ value that was less than 80% of the baseline and 6 had at least one ScO₂ value that was less than 75% of the baseline. Four patients of the cohort had ScO₂ values less than 80% of the baseline for more than 50% of the laparoscopic procedure.

Conclusions:

Although relatively uncommon, significant changes in cerebral oxygenation do occur in some patients during insufflation for laparoscopic surgery.

Comparison of end-tidal and transcutaneous measures of carbon dioxide during general anaesthesia in severely obese adults

BACKGROUND

Patients with severe obesity (body mass index (BMI) greater than 35 kg x m(-2)) present difficulties for end-tidal carbon dioxide (FE'(CO(2))) monitoring. Previous studies suggest that transcutaneous (TC) carbon dioxide measurements could be valuable, so we compared FE' and TC measures with Pa(CO(2)) in severely obese patients during anaesthesia.

METHODS

We studied patients with severe obesity (BMI >or=40 kg x m(-2)) undergoing gastric bypass surgery. Carbon dioxide was measured with both FE' and TC devices. The difference between each measure (FE'(CO(2)) and TC-CO(2)) and the Pa(CO(2)) was averaged for each patient to provide one value, and data compared with a non-paired, two-way t-test, Fisher's exact test.

RESULTS

We studied 30 adults (aged 18-54 yr, mean 41, SD 8.0 yr; weight: 115-267 kg, mean 162, SD 35 kg). The absolute difference between the TC-CO(2) and Pa(CO(2)) was 0.2 (0.2) (mean, SD) kPa while the absolute difference between the FE'(CO(2)) and Pa(CO(2)) was 0.7 (0.4) kPa (P<0.0001). The bias and precision were +0.1 (0.3) kPa for TC vs arterial carbon dioxide and -0.7 (0.4) kPa for FE' vs arterial carbon dioxide.

CONCLUSIONS

Transcutaneous carbon dioxide monitoring provides a better estimate of Pa(CO(2)) than FE'(CO(2)) in patients with severe obesity.

Effects of rapacuronium on respiratory function during general anesthesia: a comparison with cis-atracurium

BACKGROUND

With its introduction for widespread clinical use, there has been an increase in reports of bronchospasm related to the administration of rapacuronium. As it is commonly used for rapid sequence intubation, it has been suggested that these effects may be related to an inadequate depth of anesthesia. The current study examines the airway effects of rapacuronium in tracheally intubated, anesthetized adults.

METHODS

Endotracheal intubation was accomplished without the use of neuromuscular blocking agents. Dynamic compliance, tidal volume, peak inspiratory flow rate, peak expiratory flow rate, and peak inflating pressure were measured after administration of either rapacuronium (1.5 mg/kg) or cis-atracurium (0.2 mg/kg) to 20 adult patients (10 received rapacuronium and 10 received cis-atracurium) anesthetized with propofol-remifentanil.

RESULTS

Statistically significant increases in peak inflating pressure (22 +/- 6 to 28 +/- 9 cm H2O, P = 0.0012) and decreases in dynamic compliance (108 +/- 43 to 77 +/- 41 ml/cm H2O, P = 0.0001), peak inspiratory flow rate (0.43 +/- 0.11 to 0.39 +/- 0.09 l/s, P = 0.0062), peak expiratory flow rate (0.67 +/- 0.10 to 0.59 +/- 0.09 l/s, P = 0.0015), and tidal volume (744 +/- 152 to 647 +/- 135 ml, P = 0.0293) occurred after administration of rapacuronium. No changes were seen after administration of cis-atracurium.

CONCLUSION

These data demonstrate that rapacuronium, but not cis-atracurium, has significant airway effects in intubated, mechanically ventilated adults.

Venous air embolism during endoscopic strip craniectomy for repair of craniosynostosis in infants

BACKGROUND

Various studies have reported an incidence of venous air embolism (VAE) as high as 82.6% during surgical procedures for craniosynostosis. There has been an increase in the use of minimally invasive, endoseopie surgical procedures, including applications for endoscopic strip craniectomy. The current study prospectively evaluated the incidence of VAF during endoscopic strip craniectomy.

METHODS

Continuous, intraoperative monitoring for VAE was performed using precordial Doppler monitoring. A recording was made of the Doppler tones and later reviewed to verify its accuracy.

RESULTS

The cohort for the study included 50 consecutive neonates and infants ranging in age from 3.5 to 36 weeks and ranging in weight from 3 to 9 kg. Surgical time varied from 31 to 95 min for a total of 2,701 mm of operating time, during which precordial Doppler tones were auscultated. In 46 patients, there was no evidence of VAE. In four patients, there was a single episode of VAE. Two of the episodes of VAE were grade I (change in Doppler tones), and two were grade H (change in Doppler tones and decrease in end-tidal carbon dioxide). No grade III (decrease in systolic blood pressure by 20% from baseline) VAF was noted.

CONCLUSION

In addition to previously reported benefits of decreased blood loss, decreased surgical time, and improved postoperative recovery time, the authors noted a low incidence of VAF during endoscopic strip craniectomy in neonates and infants.

Rapacuronium administration to patients receiving phenytoin or carbamazepine

Patients receiving anticonvulsants such as phenytoin or carbamazepine may be resistant to neuromuscular blocking agents. The authors report the response to rapacuronium bromide (1.5 mg/kg) in two adult patients; one receiving phenytoin and the other receiving carbamazepine. In both patients, there was a delay in achieving maximum blockade; 100% depression of the first twitch was never achieved in the patient receiving phenytoin. Recovery of neuromuscular function was rapid. In the patient receiving phenytoin and carbamazepine respectively, the clinical duration (time to return of T1% to 25% of baseline) was 5 and 9 minutes, the recovery index (T1 25%-75%) was 4 minutes and 3 minutes, and the time to return of T4/T1 to greater than 0.7 was 15 minutes and 18 minutes 40 seconds. As has been reported with other neuromuscular blocking agents of the aminosteroid class, the clinical duration and the recovery index of rapacuronium are shortened in patients receiving either phenytoin or carbamazepine.

Impact of the initial doses of rocuronium and pancuronium on subsequent maintenance for neuromuscular block

PURPOSE

To determine the impact of the neuromuscular blocking agent given for intubation on the duration of effect of multiple maintenance doses of pancuronium and rocuronium.

METHODS

Seventy-eight subjects were randomly assigned to receive one of four dosing combinations for intubation and neuromuscular maintenance: rocuronium for intubation and maintenance, rocuronium for intubation and pancuronium for maintenance, pancuronium for intubation and rocuronium for maintenance, or pancuronium for both. Each time that the first twitch response returned to 25% of the baseline value, the duration of the dose was determined and another maintenance dose was administered. The duration of action of the maintenance doses was compared between the groups.

RESULTS

Twitch suppression from the first maintenance dose was shorter for subjects who received rocuronium for both doses (Group RR) compared with that for subjects that received pancuronium (Groups PR & PP) as their intubation dose (17.6 vs 34 & 59.8 min, respectively, P < 0.05). Subjects who received rocuronium followed by pancuronium (Group RP) showed a shorter duration of twitch suppression after the first maintenance dose than the group that received pancuronium for both doses (Group PP) (21.3 vs 59.8 min, P < 0.05). By the third maintenance dose, the influence of the intubating dose on the maintenance dose duration had essentially diminished.

CONCLUSIONS

For combinations of rocuronium and pancuronium, the duration of twitch suppression after a maintenance dose is only dependent on the first agent given for the first two maintenance doses administered.

Rapacuronium administration to two children with Duchenne's muscular dystrophy

Children with Duchenne's muscular dystrophy should not be exposed to succinylcholine because of the risk of hyperkalemic cardiac arrest and rhabdomyolysis. This report describes the response to rapacuronium bromide in two patients with Duchenne's muscular dystrophy. Both patients had a recovery index 2 times longer than that reported in children with normal neuromuscular function.

Gene therapy for prostate cancer

Prostate cancer remains one of the most significant challenges in clinical oncology, yet present therapies provide incomplete treatment in many cases. Innovative and practical gene therapy-based approaches will prove invaluable in filling the gaps that now exist in the treatment of localized and distant disease. Although multiple potential strategies have been developed, early clinical trials in prostate cancer gene therapy are now in the phase I/II stage of development. Novel preclinical and early clinical data should be considered optimistically, yet cautiously, as this field emerges from its infancy.

Early experience and learning curve associated with laparoscopic Nissen fundoplication

BACKGROUND

Laparoscopic approach for hiatal hernia repair is relatively new. Information on the learning curve is limited.

METHODS

From January 1994 to September 1996, 280 patients underwent antireflux surgery at our institution. A laparoscopic repair was attempted in 60 patients (21.4%). There were 38 men and 22 women. Median age was 49 years (range 21 to 78 years). Indications for operation were gastroesophageal reflux in 59 patients and a large paraesophageal hernia in one. A Nissen fundoplication was performed in all patients; 53 (88.3%) had concomitant hiatal hernia repair.

RESULTS

In eight patients (13.3%) the operation was converted to an open procedure. Median operative time for the 52 patients who had laparoscopic repair was 215 minutes (range 104 to 320 minutes). There were no deaths. Complications occurred in five patients (9.6%). Median hospitalization was 2 days (range 1 to 5 days). Median operative time and median hospitalization were significantly longer in the first 26 patients than in the subsequent 25 patients (248 vs 203 minutes and 2 days vs 1 day, respectively; p = 0.03). Seven of the first 30 patients (23.3%) required laparotomy as compared with two of the second 30 (6.7%) (p = 0.07). Follow-up in the 51 patients who had laparoscopic fundoplication for reflux was complete in 50 (98.0%) and ranged from 7 to 38 months (median 13 months). Functional results were classified as excellent in 34 patients (68.0%), good in 6 (12.0%), fair in 7 (14.0%), and poor in 3 (6.0%). Three patients were reoperated on for recurrent reflux symptoms at 5, 5, and 11 months.

CONCLUSIONS

We conclude that laparoscopic Nissen fundoplication can be performed safely. The operative time, hospitalization, and conversion rate to laparotomy are higher during the early part of the experience, but all are reduced after the learning curve.

Intracranial pressure, middle cerebral artery flow velocity, and plasma inorganic fluoride concentrations in neurosurgical patients receiving sevoflurane or isoflurane

This study examined the concentration-related effects of sevoflurane and isoflurane on cerebral physiology and plasma inorganic fluoride concentrations. Middle cerebral artery flow velocity (Vmca), intracranial pressure (ICP), electroencephalogram (EEG) activity, and jugular bulb venous oxygen saturation were measured, and cerebral perfusion pressure (CPP) and estimated cerebral vascular resistance (CVRe) were calculated at baseline and at 0.5, 1.0, and 1.5 minimum alveolar anesthetic concentration (MAC) sevoflurane (n = 8) or isoflurane (n = 6). Mannitol 0.5-0.75 g/kg was given before dural incision, and blood was sampled for plasma inorganic fluoride during surgery and for up to 72 h postoperatively. Both sevoflurane and isoflurane decreased Vmca (to 31 +/- 12 - 36 +/- 14 cm/s, mean +/- SD), did not significantly alter ICP (13 +/- 9 - 15 +/- 11 mm Hg), and did not cause epileptiform EEG activity. With sevoflurane, decreased Vmca was accompanied by decreased CPP and unchanged CVRe at 0.5 MAC, and unchanged CPP and increased CVRe at 1.0 and 1.5 MAC. Plasma inorganic fluoride was 39.0 +/- 12.9 microM at the end of anesthesia (3.2 +/- 2.0 MAC hours) with sevoflurane, similar to the value (36.2 +/- 3.9 microM) for 3.7 +/- 0.1 MAC hours sevoflurane in patients not receiving mannitol. Decreased Vmca during sevoflurane presumably results from decreased cerebral metabolic rate, with CVRe changing secondarily in accord with CPP. Plasma inorganic fluoride does not seem to be altered by mannitol-induced diuresis.

IMPLICATIONS

In neurosurgical patients, sevoflurane decreased middle cerebral artery flow velocity and caused no epileptiform electroencephalogram activity and no increase of intracranial pressure or plasma inorganic fluoride. These effects are suitable for neurosurgery. Two other possible effects of sevoflurane, i.e., increased cerebrospinal fluid volume and/or intracranial elastance, may not be suitable for neurosurgery and warrant further study.

Fuzzy logic for model adaptation of a pharmacokinetic-based closed loop delivery system for pancuronium

In this paper, we investigate the ability of fuzzy to adapt the parameters of a pharmacokinetic and pharmacodynamic model-based controller for the delivery of the muscle relaxant pancuronium. The system uses the model to control the rate of drug delivery and uses feedback from a sensor which measures muscle relaxation level to adapt the model using fuzzy logic. The control strategy administers mini-bolus doses of pancuronium and modulates the magnitude and time interval between the bolus doses to maintain a patient's muscle relaxation within an allowable range specified by the user. Before each new dose is given, the fuzzy logic adaptation scheme uses the error between the predicted patient response and the measured response to adapt the model. The system was tested using computer simulation by varying the parameters of the model by 50% from their nominal values. It was also evaluated in a clinical trial of five patients undergoing surgical procedures lasting 5 h or longer.

Clinical analysis of the flexor hallucis brevis as an alternative site for monitoring neuromuscular block from mivacurium

STUDY OBJECTIVES

To compare the flexor hallucis brevis, which is responsible for flexion of the great toe, to the adductor pollicis as a site for monitoring the onset and recovery from neuromuscular block after an intubating dose of mivacurium chloride.

DESIGN

Prospective patient-controlled study.

SETTING

University teaching hospital.

PATIENTS

10 ASA physical status I and II adults (age 18 to 55 years, 6 women, 4 men) scheduled for elective procedures requiring muscle relaxation for tracheal intubation.

MEASUREMENTS AND MAIN RESULTS

Patients were monitored at the adductor pollicis and the flexor hallucis brevis during the onset and recovery of neuromuscular block, which was administered to facilitate tracheal intubation. All subjects were given mivacurium 0.2 mg/kg over 30 seconds. Their train-of-four (TOF) response was continually monitored at both sites until the patient recovered from the intubating dose to a TOF ratio of 0.75. The time to onset of neuromuscular block, recovery of the first TOF response, and recovery to a TOF ratio of 0.75 were compared between the two monitoring sites using the Wilcoxon signed rank test. Following administration of the intubating dose of mivacurium, the loss of all twitch response occurred 1.2 minutes sooner at the adductor pollicis than at the flexor hallucis brevis (p < 0.02). Reappearance of the first twitch occurred 0.49 minutes slower at the adductor pollicis, although this difference was not statistically significant. The time to recovery to a TOF ratio of 0.75 at the adductor pollicis was slower by 2.83 minutes (p = 0.046).

CONCLUSIONS

Due to its lag behind the adductor pollicis, the flexor hallucis brevis is not a good indicator of when to intubate the trachea during the onset of neuromuscular block; however, its faster recovery may make it useful for monitoring deep neuromuscular block intraoperatively or during recovery when the adductor pollicis TOF response still shows complete blockade.

Long-term results after reoperation for failed antireflux procedures

From January 1960 to June 1995, 185 patients underwent reoperation without esophageal resection for symptoms of recurrent gastroesophageal reflux disease. There were 102 men and 83 women. Median age was 58 years (range 20 to 84 years). A single previous antireflux operation had been performed in 147 patients, two in 33, and three in 5. The median interval between the reoperation and the previous operation was 36 months (range 1 to 291 months). Indications for reoperation were symptoms in 184 patients and a large paraesophageal hernia in one patients. The surgical approach was by means of a thoracotomy in 133 patients (71.9%), laparotomy in 27 (14.6%), and a thoracoabdominal incision in 25 (13.5%). A Nissen fundoplication was performed in 107 patients (57.8%), Belsey fundoplication in 47 (25.4%), truncal vagotomy and antrectomy with Roux-en-Y reconstruction in 17 (9.2%), anatomic hernia repair in 12 (6.5%), and Hill gastropexy in 2 (1.1%). A Collis gastroplasty was added to the fundoplication in 116 patients (62.7%), and a pyloroplasty was performed in 17 (9.2%). There was one operative death (0.5%). Complications occurred in 47 patients (25.4%). Median postoperative hospitalization was 9 days (range 5 to 58 days). Follow-up was complete in 156 patients (84.3%) and ranged from 3 to 283 months (median 44 months). Improvement occurred in 137 patients (87.8%). Functional results were classified as excellent in 65 patients (41.6%), good in 29 (18.6%), fair in 43 (27.6%), and poor in 19 (12.2%). No single operative approach or procedure proved to be functionally superior. We conclude that reoperation with esophageal preservation after a failed antireflux procedure will result in significant functional benefit and can be performed with low mortality and acceptable morbidity. The type of repair should be tailored to the individual patient.