Hyper-Realistic Advanced Surgical Skills Package with Cut Suit Simulator Improves Trainee Surgeon Confidence in Operative Trauma

BACKGROUND

Adequate exposure to operative trauma is not uniform across surgical residencies, and therefore it can be challenging to achieve competency during residency alone. This study introduced the Cut Suit surgical simulator with an Advanced Surgical Skills Package, which replicates traumatic bleeding and organ injury, into surgery resident training across multiple New York City trauma centers.

METHODS

Trainees from 6 ACS-verified trauma centers participated in this prospective, observational trial. Groups of 3-5 trainees (post-graduate year 1-6) from 6 trauma centers within the largest public healthcare network in the U.S. participated. Residents were asked to perform various operative tasks including rescucitative thoracotomy, exploratory laprotomy, splenectomy, hepatorrhaphy, retroperitoneal exploration, and small bowel resection on a severely injured simulated patient. Pre- and post-course surveys were used to evaluate trainees' confidence performing these procedures and quizzes were used to evaluate participants' knowledge acquisition after the simulation.

RESULTS

One hundred twenty-three surgery residents participated in the evaluation. 68% of participants agreed that the simulation was similar to actual surgery. After the simulation, the percentage of residents reporting being "more confident" or "most confident" in independently managing operative trauma patients increased by 42% (P < .01). There was a significant increase in the proportion of residents reporting being "more confident" or "most confident" managing all procedures performed. Post-activity quiz scores improved by an average of 20.4 points.

DISCUSSION

The Cut Suit surgical simulator with ASSP is a realistic and useful adjunct in training surgeons to manage complex operative trauma.

Surgical stabilization of rib fractures in patients with pulmonary comorbidities

INTRODUCTION

Prior studies have shown that the surgical stabilization of rib fractures (SSRF) for patients with multiple rib fractures is associated with improved outcomes by restoring chest wall integrity and decreasing time to return to prior functional status. It is unclear if patients with pulmonary comorbidities (PCM) would benefit from this procedure.

OBJECTIVE

To compare the difference in morbidity and mortality of patients with multiple rib fractures undergoing SSRF who have underlying PCM to those who do not have PCM.

METHODS

We performed a retrospective cohort study of patients with multiple rib fractures using data from the Trauma Quality Improvement Program (January 2015 to December 2018). Patients with penetrating injuries, those who died within the first 24 h, those with substantial head, spine, or abdominopelvic injuries, and those who were pregnant, were excluded. A PCM was defined as chronic lower respiratory disease, active smoking, or morbid obesity. Dichotomous outcomes were adjusted for potential confounders by creating a propensity score for PCM and applying inverse probability weighting. The propensity score accounted for multiple patient-level and hospital level covariates. Continuous outcomes were adjusted for these same covariates using multivariable quantile regression.

RESULTS

Of the 4,084 patients who underwent SSRF, 3048 (75%) were males, the median age was 57 years [IQR 47, 66], and 1504 (37%) had at least one PCM. After adjusting for the propensity score, patients with PCM who underwent SSRF had no significant difference in mortality compared to those without PCM (absolute difference, 0.7% [95% CI -0.2, 1.7]). Similarly, there was no significant difference in time on the ventilator (0.6 days [-0.1, 1.4]). Patients with PCM, however, had a statistically significantly longer hospital LOS (0.8 days [0.3, 1.3]) and ICU LOS (0.6 days [0.1, 1.1]), higher risk of tracheostomy (2.7% [0.1, 4.6]) and higher probability of pulmonary complications (2.7% [1.2, 4.2]), compared to those without PCM.

CONCLUSION

Among patients with multiple rib fractures who undergo SSRF, having a PCM did not result in a clinically important higher probability of dying or experiencing substantial morbidity. This factor should not exclude patients with PCM from receiving SSRF for multiple rib fractures but the small increased risk in morbidity should be discussed with patients prior to SSRF.

Sequential monoscopic image-guided motion compensation in tomotherapy stereotactic body radiotherapy (SBRT) for prostate cancer

PURPOSE

To manage intra-fractional motions, recent developments in tomotherapy enable a unique capability of adjusting MLC/jaw to track the moving target based on the intra-fractional motions detected by sequential monoscopic imaging. In this study, we evaluated the effectiveness of motion compensation with a realistic imaging rate for prostate stereotactic body radiotherapy (SBRT). The obtained results will guide optimizing treatment parameters and image-guided radiation therapy (IGRT) in tomotherapy using this approach.

METHODS

Ten retrospective prostate cases with actual prostate motion curves previously recorded through the Calypso system were used in this study. Based on the recorded peak-to-peak motion, these cases represented either large (> 5 mm) or median (≤ 5 mm) intra-fractional prostate motions. All the cases were re-planned on tomotherapy using 35 Gy/5 fractions SBRT regimen and three different jaw settings of 1 cm static, 2.5 cm static, and 2.5 cm dynamic jaw. Two motion compensation methods were evaluated: a complete compensation that adjusted the jaw and MLC every 0.1 s (the same rate as the Calypso motion trace), and a realistic compensation that adjusted the jaw and MLC at an average imaging interval of 6 s from sequential monoscopic images. An in-house 4D dose calculation software was then applied to calculate the dosimetric outcomes from the original motion-free plan, the motion-contaminated plan, and the two abovementioned motion-compensated plans. During the process, various imaging rates were also simulated in one case with unusually large motions to quantify the impact of the KV-imaging rate on the effectiveness of motion compensation.

RESULTS

The effectiveness of motion compensation was evaluated based on the PTV coverage and OAR sparing. Without any motion-compensation, the PTV coverage (PTV V100%) of patients with large prostate motions decreased remarkably to 55%-82% when planning with the 1 cm jaw but to a less level of 67-94% with the 2.5 cm jaw. In contrast, motion compensation improved the PTV coverage (>92%) when combined with the 2.5 cm jaw, but less effective, around 75%-94%, with the 1 cm jaw. For OAR sparing, the bladder D1cc, bladder D10cc, and rectum D1cc all increased in the motion-contaminated plans. Motion compensation improved OAR sparing to the equivalent level of the original motion-free plans. For patients with median prostate motion, motion-induced degradation in PTV coverage was only observed when planning with the 1 cm jaw. After motion compensation, the PTV coverage improved to better than 94% for all three jaw settings. Additionally, the effectiveness of motion compensation depends on the imaging rate. Motion compensation with a typical rate of two KV images per gantry rotation effectively reduces motion-induced dosimetric uncertainties. However, a higher imaging rate is recommended when planning with a 1 cm jaw for patients with large motions.

CONCLUSION

Our results demonstrated that the performance of sequential monoscopic imaging-guided motion compensation on tomotherapy depends on the amplitude of intra-fractional prostate motion, the plan parameter settings, especially jaw setting, gantry rotation, and the imaging rate for motion compensation. Creating a patient-specific imaging guidance protocol is essential to balance the effectiveness of motion compensation and achievable imaging rate for intra-fractional motion tracking.

When New York City was the COVID-19 pandemic epicenter: The impact on trauma care

BACKGROUND

During early spring 2020, New York City (NYC) rapidly became the first US epicenter of the COVID-19 pandemic. With an unparalleled strain on health care resources, we sought to investigate the impact of the pandemic on trauma visits and mortality in the United States' largest municipal hospital system.

METHODS

We conducted a retrospective multicenter cohort study of the five level 1 trauma centers in NYC's public health care system, New York City's Health and Hospitals Corporation. Clinical characteristics, mechanism of injury, and mortality of trauma patients presenting during the early pandemic (March 1, 2020, to May 31, 2020) were compared with a similar period in the previous 2 years. To account for important patient and hospital-level confounding variables, we created a propensity score for treatment and applied inverse probability weighting.

RESULTS

In March to May 2020, there was a 25% decrease in median number of monthly trauma visits (693 vs. 528; p = 0.02) but a 50% increase (15% vs. 22%; p = <0.001) in patients presenting for penetrating injuries, compared with the same period for 2018 and 2019. Injured patients with COVID were significantly more likely to die compared with those without COVID-19 (10.5% vs. 3.6%; p < 0.001). Overall, there was no significant difference in mortality for non-COVID-injured New Yorkers cared for in 2020 compared with 2018 and 2019. Less severely injured non-COVID patients (Injury Severity Score, <15), however, were significantly more likely to die compared with this same subgroup in 2018 and 2019 (adjusted relative risk, 2.7 [95% confidence interval, 1.5-4.7]).

CONCLUSION

Despite a decline in overall trauma visits during the early part of the COVID pandemic in NYC, there was a significant increase in the proportion of penetrating mechanisms. Less-injured non-COVID patients experienced an increase in mortality in the early pandemic, possibly from a depletion of human and hospital resources from the large influx of COVID patients. These data lend support to the safeguarding of trauma system resources in the event of a future pandemic.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level III.

Extended Noninvasive Glucose Monitoring in the Interstitial Fluid Using an Epidermal Biosensing Patch

An effective, noninvasive glucose monitoring technology could be a pivotal factor for addressing the major unmet needs for managing diabetes mellitus (DM). Here, we describe a skin-worn, disposable, wireless electrochemical biosensor for extended noninvasive monitoring of glucose in the interstitial fluid (ISF). The wearable platform integrates three components: a screen-printed iontophoretic electrode system for ISF extraction by reverse iontophoresis (RI), a printed three-electrode amperometric glucose biosensor, and an electronic interface for control and wireless communication. Prolonged on-body glucose monitoring of up to 8 h, including clinical trials conducted in individuals with and without DM, demonstrated good correlation between glucose blood and ISF concentrations and the ability to monitor dynamically changing glucose levels upon food consumption, with no evidence of skin irritation or discomfort. Such successful extended operation addresses the challenges reported for the GlucoWatch platform by using a lower RI current density at shorter extraction times, along with a lower measurement frequency. Such a noninvasive skin-worn platform could address long-standing challenges with existing glucose monitoring platforms.

Do surgical emergencies stay at home? Observations from the first United States Coronavirus epicenter

BACKGROUND

During the coronavirus disease 2019 pandemic, New York instituted a statewide stay-at-home mandate to lower viral transmission. While public health guidelines advised continued provision of timely care for patients, disruption of safety-net health care and public fear have been proposed to be related to indirect deaths because of delays in presentation. We hypothesized that admissions for emergency general surgery (EGS) diagnoses would decrease during the pandemic and that mortality for these patients would increase.

METHODS

A multicenter observational study comparing EGS admissions from January to May 2020 to 2018 and 2019 across 11 NYC hospitals in the largest public health care system in the United States was performed. Emergency general surgery diagnoses were defined using International Classification Diseases, Tenth Revision, codes and grouped into seven common diagnosis categories: appendicitis, cholecystitis, small/large bowel, peptic ulcer disease, groin hernia, ventral hernia, and necrotizing soft tissue infection. Baseline demographics were compared including age, race/ethnicity, and payor status. Outcomes included coronavirus disease (COVID) status and mortality.

RESULTS

A total of 1,376 patients were admitted for EGS diagnoses from January to May 2020, a decrease compared with both 2018 (1,789) and 2019 (1,668) (p < 0.0001). This drop was most notable after the stay-at-home mandate (March 22, 2020; week 12). From March to May 2020, 3.3%, 19.2%, and 6.0% of EGS admissions were incidentally COVID positive, respectively. Mortality increased in March to May 2020 compared with 2019 (2.2% vs. 0.7%); this difference was statistically significant between April 2020 and April 2019 (4.1% vs. 0.9%, p = 0.045).

CONCLUSION

Supporting our hypothesis, the coronavirus disease 2019 pandemic and subsequent stay-at-home mandate resulted in decreased EGS admissions between March and May 2020 compared with prior years. During this time, there was also a statistically significant increase in mortality, which peaked at the height of COVID infection rates in our population.

LEVEL OF EVIDENCE

Epidemiological, level IV.

Is There an Age Cutoff for Intracranial Pressure Monitoring?: A Propensity Score Matched Analysis of the National Trauma Data Bank

BACKGROUND

Despite mostly favorable past evidence for use of intracranial pressure monitoring (ICPM), more recent data question not only the indications but also the utility of ICPM. The Fourth Edition Brain Trauma Foundation guidelines offer limited indications for ICPM. Evidence supports ICPM for reducing mortality in patients with severe traumatic brain injury (TBI) and cites decreased survival in elderly patients.

METHODS

All patients ≥ 18 years of age with isolated TBI, head Abbreviated Injury Scale (AIS) ≥ 3, and a Glasgow Coma Scale (GCS) ≤ 8 between 2008 and 2014 were included from the National Trauma Data Bank. Exclusion criteria were head AIS = 6 and death within 24 hours. Patients with and without ICPM were compared using TBI-specific variables. Patients were then matched via propensity-score matching (PSM), and the odds ratio (OR) of death with ICPM was determined using logistic regression modeling for 8 different age strata.

RESULTS

A total of 23,652 patients with a mean age of 56 years, median head AIS of 4, median GCS of 3, and overall mortality of 29.2% were analyzed. After PSM, ICPM was associated with death beginning at the age stratum of 56-65 years. Intracranial pressure monitoring was associated with survival beginning at the age-group 36-45 years.

DISCUSSION

Based on a large propensity-matched sample of TBI patients, ICPM was not associated with improved survival for TBI patients above 55 years of age. Until level 1 evidence is available, this age threshold should be considered for further prospective study in determining indications for ICPM.

Ketorolac Use for Pain Management in Trauma Patients With Rib Fractures Does not Increase of Acute Kidney Injury or Incidence of Bleeding

INTRODUCTION

Ketorolac is useful in acute pain management to avoid opiate-related complications; however, some surgeons fear associated acute kidney injury (AKI) and bleeding despite a paucity of literature on ketorolac use in trauma patients. We hypothesized that our institution's use of intravenous ketorolac for rib fracture pain management did not increase the incidence of bleeding or AKI.

METHODS

Rib fracture patients aged 15 years and above admitted between January 2016-June 2018 were identified in our trauma registry along with frequency of bleeding events. AKI was defined as ≥ 1.5x increase in serum creatinine from baseline measured on the second day of admission (after 24 hours of resuscitation) or an increase of ≥ .3 mg/dL over a 48-hour period. Patients receiving ketorolac were compared to patients with no ketorolac use.

RESULTS

Two cohorts of 199 control and 205 ketorolac patients were found to be similar in age, gender, admission systolic blood pressure (SBP), injury severity score, intravenous radiocontrast received, and transfusion requirements. Analysis revealed no difference in frequency of AKI using both definitions (8% vs. 7.3%, P = .79) and (19.6% vs. 15.1%, P = .24), respectively, or bleeding events (2.5% vs. 0%, P = .03). Logistic regression demonstrated that ketorolac use was not an independent predictor for AKI but age and admission SBP < 90 were.

CONCLUSION

Use of ketorolac in this cohort of trauma patients with rib fractures did not increase the incidence of AKI or bleeding events.

Fast Statistical Iterative Reconstruction for Mega-voltage Computed Tomography

Statistical iterative reconstruction is expected to improve the image quality of computed tomography (CT). However, one of the challenges of iterative reconstruction is its large computational cost. The purpose of this review is to summarize a fast iterative reconstruction algorithm by optimizing reconstruction parameters. Megavolt projection data was acquired from a TomoTherapy system and reconstructed using in-house statistical iterative reconstruction algorithm. Total variation was used as the regularization term and the weight of the regularization term was determined by evaluating signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and visual assessment of spatial resolution using Gammex and Cheese phantoms. Gradient decent with an adaptive convergence parameter, ordered subset expectation maximization (OSEM), and CPU/GPU parallelization were applied in order to accelerate the present reconstruction algorithm. The SNR and CNR of the iterative reconstruction were several times better than that of filtered back projection (FBP). The GPU parallelization code combined with the OSEM algorithm reconstructed an image several hundred times faster than a CPU calculation. With 500 iterations, which provided good convergence, our method produced a 512 × 512 pixel image within a few seconds. The image quality of the present algorithm was much better than that of FBP for patient data. J. Med. Invest. 67 : 30-39, February, 2020.

A unique case of Lemierre's syndrome status post blunt cervical trauma

BACKGROUND

Lemierre's syndrome is a rare but potentially fatal condition. The course is characterized by acute tonsillopharyngitis, bacteremia, internal jugular vein thrombosis, and septic embolization. There have been some cases secondary to penetrating trauma to the neck. Literature review has yielded no cases secondary to blunt neck trauma in the absence of oropharyngeal injury. We aim to shed light on this unique cause of Lemierre's syndrome, so as to raise the index of suspicion for clinicians working up patients with blunt cervical trauma.

METHODS

We present a case of a 25-year-old male restrained driver who presented with left neck and shoulder pain with a superficial abrasion to the left neck from the seatbelt who was discharged same day by the Emergency Room physicians. He returned to the Emergency Department two days later with abdominal pain. As a part of his repeat evaluation, a set of blood cultures were sent and was sent home that day. The patient was called back to the hospital one day later as preliminary blood cultures were positive for Gram positive cocci and Gram negative anaerobes. Computerized tomography scan of the neck revealed extensive occlusive left internal jugular vein thrombosis and fluid collections concerning for abscesses, concerning for septic thrombophlebitis. The patient continued to decompensate, developing severe sepsis complicated by disseminated intravascular coagulation.

RESULTS

The patient underwent a left neck exploration with en bloc resection of the left internal jugular vein, drainage of abscesses deep to the sternocleidomastoid, and washout/debridement of necrotic tissue. Direct laryngoscopy at the time of surgery revealed no injury to the aerodigestive tract. Wound cultures were consistent with blood cultures and grew Fusobacterium necrophorum, Staphylococcus epidermidis, and Methicillin-resistant staphylococcus aureus. The patient underwent two subsequent operative wound explorations without any evidence of residual infection. The patient was discharged home on postoperative day 13 on a course of antibiotics and aspirin.

CONCLUSION

This case illustrates the importance of diagnosis of Lemierre's syndrome after an unconventional inciting event (blunt cervical trauma) and appropriate treatment.

State of Rib Fracture Care: A NTDB Review of Analgesic Management and Surgical Stabilization

Thoracic analgesia plays a key role in management and outcomes of rib fractures and can generally be broken down into oral or parenteral medication administration and regional analgesia. Surgical stabilization of rib fractures (SSRF) may be an underused resource in the management of rib fractures. This study describes recent trends in rib fracture management and outcomes. National Trauma Data Bank datasets from 2008 to 2014 were reviewed. Patients with three or more rib fractures were identified, and the frequencies of epidural analgesia (EA), other regional analgesia, and SSRF were analyzed. Those older than 65 years were more likely to be admitted to the ICU but had shorter ICU length of stay, lower intubation, and need for tracheostomy rates. In addition, those older than 65 years had about 2.5 times higher mortality (6.3% vs 2.6%, P < 0.001). EA was used in only 3 per cent of the population and more commonly in the older than 65 years group (3.7% vs 2.8%, P < 0.001). Regardless of age, SSRF was more commonly performed when compared with the placement of EA (5.8% vs 3%). This difference was even greater in the younger than 65 years group, where 7 per cent underwent SSRF. Utilization of EA remains low nationally. SSRF should be considered not only for chest wall stabilization but also as an analgesic modality in selected patients. A more complete accounting of analgesic care in rib fracture patients is needed to allow a more detailed analysis of analgesia for rib fracture–related pain to elucidate optimal treatment.

State of Rib Fracture Care: A NTDB Review of Analgesic Management and Surgical Stabilization

Thoracic analgesia plays a key role in management and outcomes of rib fractures and can generally be broken down into oral or parenteral medication administration and regional analgesia. Surgical stabilization of rib fractures (SSRF) may be an underused resource in the management of rib fractures. This study describes recent trends in rib fracture management and outcomes. National Trauma Data Bank datasets from 2008 to 2014 were reviewed. Patients with three or more rib fractures were identified, and the frequencies of epidural analgesia (EA), other regional analgesia, and SSRF were analyzed. Those older than 65 years were more likely to be admitted to the ICU but had shorter ICU length of stay, lower intubation, and need for tracheostomy rates. In addition, those older than 65 years had about 2.5 times higher mortality (6.3% vs 2.6%, P < 0.001). EA was used in only 3 per cent of the population and more commonly in the older than 65 years group (3.7% vs 2.8%, P < 0.001). Regardless of age, SSRF was more commonly performed when compared with the placement of EA (5.8% vs 3%). This difference was even greater in the younger than 65 years group, where 7 per cent underwent SSRF. Utilization of EA remains low nationally. SSRF should be considered not only for chest wall stabilization but also as an analgesic modality in selected patients. A more complete accounting of analgesic care in rib fracture patients is needed to allow a more detailed analysis of analgesia for rib fracture-related pain to elucidate optimal treatment.

Partial Aortic Occlusion using Resuscitative Endovascular Balloon Occlusion of the Aorta (P-REBOA) in Ruptured Abdominal Aortic Aneurysm

Ruptured abdominal aortic aneurysm is often a fatal event without immediate intervention for the associated hemorrhagic shock and impending cardiovascular collapse. We report a case of a ruptured abdominal aortic aneurysm managed with partially occlusive resuscitative endovascular balloon occlusion of the aorta (P-REBOA) as a means to gain proximal control, tailor blood pressure goals, while allowing time to obtain access and repair the ruptured aneurysm.

Metaraminol use during spinal anaesthesia for caesarean section: a meta-analysis of randomised controlled trials

INTRODUCTION

During caesarean section, the use of a vasopressor is often required to achieve haemodynamic stability of the parturient. Metaraminol is a vasopressor used in this context in some countries. However, the differences between metaraminol and other vasopressors remain unclear.

METHODS

A search of the PubMed, Cochrane Library, and Embase databases was performed to identify randomised controlled trials comparing the use of metaraminol with other vasopressors during spinal anaesthesia at caesarean section. The selected studies were subjected to meta-analysis and risk-of-bias assessment.

RESULTS

Four randomised, controlled trials met the selection criteria and 409 parturients who underwent an elective caesarean section were included in this meta-analysis. The quality of these trials was good. Metaraminol was associated with higher umbilical arterial pH (standardised mean difference [SMD] 0.82, 95% CI 0.01 to 1.62, P=0.05); a lower incidence of fetal acidosis (RR 0.08, 95% CI 0.01 to 0.63, P=0.02); and a lower incidence of nausea or vomiting (RR 0.16, 95% CI 0.04 to 0.57, P=0.0005) than was ephedrine. Metaraminol resulted in higher umbilical arterial pH (SMD 0.42, 95% CI 0.15 to 0.68, P=0.002) but a higher incidence of reactive hypertension (RR 1.80, 95% CI 1.32 to 2.46, P=0.0002) than did phenylephrine.

CONCLUSION

The results of this study showed that for spinal anaesthesia at elective caesarean section, metaraminol may be a more suitable vasopressor than ephedrine and its effects are at least not inferior to those of phenylephrine.

CE: The Use of Resuscitative Endovascular Balloon Occlusion of the Aorta in Treating Hemorrhagic Shock from Severe Trauma

: Hemorrhage is the leading cause of preventable death in trauma patients. In recent years, technological innovations and research efforts aimed at preventing death from hemorrhagic shock have resulted in the emergence of resuscitative endovascular balloon occlusion of the aorta (REBOA). REBOA offers a less invasive option for emergent hemorrhage control in noncompressible areas of the body without the added risks and morbidities of an ED thoracotomy. This article outlines the procedure and device used, describes the procedure's evolution, and discusses various considerations, pitfalls, and nursing implications.

End-tidal CO2 on admission is associated with hemorrhagic shock and predicts the need for massive transfusion as defined by the critical administration threshold: A pilot study

BACKGROUND

Critical administration threshold (≥3 units of packed red blood cells/h or CAT+) has been proposed as a new definition for massive transfusion (MT) that includes volume and rate of blood transfusion. CAT+ has been shown to eliminate survivor bias and be a better predictor of mortality than the traditional MT (>10 units/24h). End-tidal CO₂ (ET CO₂) negatively correlates with lactate and is an early predictor of shock in trauma patients. We conducted a pilot study to test the hypothesis that low ET CO₂ on admission predicts CAT+.

METHODS

ET CO₂ via capnography and serum lactate were prospectively collected on admission for 131 patients requiring trauma team activation. Demographic data were obtained from patient charts. Excluded were patients with isolated head injuries, traumatic arrests, or pre-hospital intubations. CAT± status was determined for each hour up to 6h from admission as described; likewise, MT± status was determined up to 24h from admission.

RESULTS

After exclusion criteria, 67 patients were analyzed. Mean age was 41.2 (SD 18.5). Thirty-three patients had a blunt mechanism of injury (49%), median ISS was 9 (interquartile range 4-19), and there were 6 deaths (9%). ET CO₂ and lactate were negatively correlated by Spearman rank-based correlation (rho=-0.41, p=0.0006). Twenty-one (31%) and 8 (12%) patients were CAT+ and traditional MT+, respectively. There were a significantly greater proportion of patients with ISS>15, ET CO₂ <35, or who died found to be CAT+. A binomial logistic regression model adjusting for age, SBP <90, HR, and ISS >15 revealed ET CO₂ < 35 to be independently predictive of CAT+ (OR 9.24, 95% CI 1.51-56.57, p=0.016).

CONCLUSIONS

This pilot study demonstrated that low ET CO₂ had strong association with standard indicators for shock and was predictive of patients meeting CAT+ criteria in the first 6h after admission. Further study to verify these results and to elucidate CAT criteria's association with mortality will require a larger sample size.

Factors Associated with Return to Work Postinjury: Can the Modified Rankin Scale Be Used to Predict Return to Work?

The ability to return to work (RTW) postinjury is one of the primary goals of rehabilitation. The modified Rankin Scale (mRS) is a validated simple scale used to assess the functional status of stroke patients during rehabilitation. We sought to determine the applicability of mRS in predicting RTW postinjury in a general trauma population. The trauma registry was queried for patients, aged 18 to 65 years, discharged from 2012 to 2013. A telephone interview for each patient included questions about employment status and physical ability to determine the mRS. Patients who had RTW postinjury were compared with those who had not (nRTW). Two hundred and thirty-four patients met the inclusion criteria. Of these, 171 (72.5%) patients RTW and 63 (26.7%) did nRTW. Patients who did nRTW were significantly older, had longer length of stay and higher rates of in-hospital complications. Multivariate analysis revealed that older patients were less likely to RTW (odds ratio = 0.961, P = 0.011) and patients with a modified Rankin score ≤2 were 15 times more likely to RTW (odds ratio = 14.932, P < 0.001). In conclusion, an mRS ≤2 was independently associated with a high likelihood of returning to work postinjury. This is the first study that shows applicability of the mRS for predicting RTW postinjury in a trauma population.

Factors Associated with Return to Work Postinjury: Can the Modified Rankin Scale be Used to Predict Return to Work?

The ability to return to work (RTW) postinjury is one of the primary goals of rehabilitation. The modified Rankin Scale (mRS) is a validated simple scale used to assess the functional status of stroke patients during rehabilitation. We sought to determine the applicability of mRS in predicting RTW postinjury in a general trauma population. The trauma registry was queried for patients, aged 18 to 65 years, discharged from 2012 to 2013. A telephone interview for each patient included questions about employment status and physical ability to determine the mRS. Patients who had RTW postinjury were compared with those who had not (nRTW). Two hundred and thirty-four patients met the inclusion criteria. Of these, 171 (72.5%) patients RTW and 63 (26.7%) did nRTW. Patients who did nRTW were significantly older, had longer length of stay and higher rates of in-hospital complications. Multivariate analysis revealed that older patients were less likely to RTW (odds ratio = 0.961, P = 0.011) and patients with a modified Rankin score ≤2 were 15 times more likely to RTW (odds ratio = 14.932, P < 0.001). In conclusion, an mRS ≤2 was independently associated with a high likelihood of returning to work postinjury. This is the first study that shows applicability of the mRS for predicting RTW postinjury in a trauma population.

Fast nastic motion of plants and bioinspired structures

The capability to sense and respond to external mechanical stimuli at various timescales is essential to many physiological aspects in plants, including self-protection, intake of nutrients and reproduction. Remarkably, some plants have evolved the ability to react to mechanical stimuli within a few seconds despite a lack of muscles and nerves. The fast movements of plants in response to mechanical stimuli have long captured the curiosity of scientists and engineers, but the mechanisms behind these rapid thigmonastic movements are still not understood completely. In this article, we provide an overview of such thigmonastic movements in several representative plants, including Dionaea, Utricularia, Aldrovanda, Drosera and Mimosa. In addition, we review a series of studies that present biomimetic structures inspired by fast-moving plants. We hope that this article will shed light on the current status of research on the fast movements of plants and bioinspired structures and also promote interdisciplinary studies on both the fundamental mechanisms of plants' fast movements and biomimetic structures for engineering applications, such as artificial muscles, multi-stable structures and bioinspired robots.

Reconstruction of the treatment area by use of sinogram in helical tomotherapy

BACKGROUND

TomoTherapy (Accuray, USA) has an image-guided radiotherapy system with a megavoltage (MV) X-ray source and an on-board imaging device. This system allows one to acquire the delivery sinogram during the actual treatment, which partly includes information from the irradiated object. In this study, we try to develop image reconstruction during treatment with helical tomotherapy.

FINDINGS

Sinogram data were acquired during helical tomotherapy delivery using an arc-shaped detector array that consists of 576 xenon-gas filled detector cells. In preprocessing, these were normalized with full air-scan data. A software program was developed that reconstructs 3D images during treatment with corrections as; (1) the regions outside the field were masked not to be added in the backprojection (a masking correction), and (2) each voxel of the reconstructed image was divided by the number of the beamlets passing through its voxel (a ray-passing correction). The masking correction produced a reconstructed image, however, it contained streak artifacts. The ray-passing correction reduced this artifact. Although the SNR (the ratio of mean to standard deviation in a homogeneous region) and the contrast of the reconstructed image were slightly improved with the ray-passing correction, use of only the masking correction was sufficient for the visualization purpose.

CONCLUSIONS

The visualization of the treatment area was feasible by using the sinogram in helical tomotherapy. This proposed method would be useful in the treatment verification.

Panel-based testing for inherited colorectal cancer: a descriptive study of clinical testing performed by a US laboratory

Next-generation sequencing enables testing for multiple genes simultaneously (‘panel-based testing’) as opposed to sequential testing for one inherited condition at a time (‘syndrome-based testing’). This study presents results from patients who underwent hereditary colorectal cancer (CRC) panel-based testing (‘ColoNext™’). De-identified data from a clinical testing laboratory were used to calculate (1) frequencies for patient demographic, clinical, and family history variables and (2) rates of pathogenic mutations and variants of uncertain significance (VUS). The proportion of individuals with a pathogenic mutation who met national syndrome-based testing criteria was also determined. Of 586 patients, a pathogenic mutation was identified in 10.4%, while 20.1% had at least one VUS. After removing eight patients with CHEK2 mutations and 11 MUTYH heterozygotes, the percentage of patients with ‘actionable’ mutations that would clearly alter cancer screening recommendations per national guidelines decreased to 7.2%. Of 42 patients with an ‘actionable’ result, 30 (71%) clearly met established syndrome-based testing guidelines. This descriptive study is among the first to report on a large clinical series of patients undergoing panel-based testing for inherited CRC. Results are discussed in the context of benefits and concerns that have been raised about panel-based testing implementation.

Conflict of interest

Cristi Radford and Jill Dolinsky are full-time employees for the commercial laboratory Ambry Genetics, which performs ColoNext™ testing. Elizabeth Chao is a paid consultant for Ambry. Deborah Cragun, Meghan Caldwell, and Tuya Pal report no potential conflicts of interest. Specifically, they are not employed by Ambry, and they did not receive any financial or other incentives from Ambry.

Quantitative characterization of tomotherapy MVCT dosimetry

Megavoltage computed tomography (MVCT) is used as image guidance for patient setup in almost every tomotherapy treatment. Frequent use of ionizing radiation for image guidance has raised concern of imaging dose. The purpose of this work is to quantify and characterize tomotherapy MVCT dosimetry. Our dose calculation was based on a commissioned dose engine, and the calculation result was compared with film measurement. We studied dose profiles, center dose, maximal dose, surface dose, and mean dose on homogeneous cylindrical water phantoms of various diameters for various scanning parameters, including 3 different jaw openings (of nominal value J4, J1, and J0.1) and couch speeds (fine, normal, and coarse). The comparison between calculation and film measurement showed good agreement. In particular, the thread pattern on the film of the helical delivery matched very well with calculation. For the J1 jaw and coarse imaging mode, the maximum difference between calculation and measurement was about 6% of the center dose. Calculation on various sizes of synthesized phantoms showed that the center dose decreases almost linearly as the phantom diameter increases, and that the fine mode (couch speed of 4mm/rotation) received twice the dose of the normal mode (couch speed of 8mm/rotation) and 3 times that of the coarse mode (couch speed of 12mm/rotation) as expected. The maximal dose ranged from 100% to ∼200% of the center dose, with increasing ratios for larger phantoms, smaller jaws, and faster couch speed. For all jaw settings and couch speeds, the mean dose and average surface dose vary from 95% to 125% of the center dose with increasing ratios for larger phantoms. We present a quantitative dosimetric characterization of the tomotherapy MVCT in terms of scanning parameters, phantom size, center dose, maximal dose, surface dose, and mean dose. The results can provide an overall picture of dose distribution and a reference data set that enables estimation of CT dose index for the tomotherapy MVCT.

High-dose MVCT image guidance for stereotactic body radiation therapy

PURPOSE

Stereotactic body radiation therapy (SBRT) is a potent treatment for early stage primary and limited metastatic disease. Accurate tumor localization is essential to administer SBRT safely and effectively. Tomotherapy combines helical IMRT with onboard megavoltage CT (MVCT) imaging and is well suited for SBRT; however, MVCT results in reduced soft tissue contrast and increased image noise compared with kilovoltage CT. The goal of this work was to investigate the use of increased imaging doses on a clinical tomotherapy machine to improve image quality for SBRT image guidance.

METHODS

Two nonstandard, high-dose imaging modes were created on a tomotherapy machine by increasing the linear accelerator (LINAC) pulse rate from the nominal setting of 80 Hz, to 160 Hz and 300 Hz, respectively. Weighted CT dose indexes (wCTDIs) were measured for the standard, medium, and high-dose modes in a 30 cm solid water phantom using a calibrated A1SL ion chamber. Image quality was assessed from scans of a customized image quality phantom. Metrics evaluated include: contrast-to-noise ratios (CNRs), high-contrast spatial resolution, image uniformity, and percent image noise. In addition, two patients receiving SBRT were localized using high-dose MVCT scans. Raw detector data collected after each scan were used to reconstruct standard-dose images for comparison.

RESULTS

MVCT scans acquired using a pitch of 1.0 resulted in wCTDI values of 2.2, 4.7, and 8.5 cGy for the standard, medium, and high-dose modes respectively. CNR values for both low and high-contrast materials were found to increase with the square root of dose. Axial high-contrast spatial resolution was comparable for all imaging modes at 0.5 lp∕mm. Image uniformity was improved and percent noise decreased as the imaging dose increased. Similar improvements in image quality were observed in patient images, with decreases in image noise being the most notable.

CONCLUSIONS

High-dose imaging modes are made possible on a clinical tomotherapy machine by increasing the LINAC pulse rate. Increasing the imaging dose results in increased CNRs; making it easier to distinguish the boundaries of low contrast objects. The imaging dose levels observed in this work are considered acceptable at our institution for SBRT treatments delivered in 3-5 fractions.

Estimating influenza incidence and rates of influenza-like illness in the outpatient setting

Please cite this paper as: Fowlkes et al. (2012) Estimating influenza incidence and rates of influenza‐like illness in the outpatient setting. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12014.

Background:  Estimating influenza incidence in outpatient settings is challenging. We used outpatient healthcare practice populations as a proxy to estimate community incidence of influenza‐like illness (ILI) and laboratory‐confirmed influenza‐associated ILI.

Methods:  From October 2009 to July 2010, 38 outpatient practices in seven jurisdictions conducted surveillance for ILI (fever with cough or sore throat for patients ≥2 years; fever with ≥1 respiratory symptom for patients <2 years). From a sample of patients with ILI, respiratory specimens were tested for influenza.

Results:  During the week of peak influenza activity (October 24, 2009), 13% of outpatient visits were for ILI and influenza was detected in 72% of specimens. For the 10‐month surveillance period, ILI and influenza‐associated ILI incidence were 20·0 (95% CI: 19·7, 20·4) and 8·7/1000 (95% CI: 8·2, 9·2) persons, respectively. Influenza‐associated ILI incidence was highest among children aged 2–17 years. Observed trends were highly correlated with national ILI and virologic surveillance.

Conclusions:  This is the first multistate surveillance system demonstrating the feasibility of using outpatient practices to estimate the incidence of medically attended influenza at the community level. Surveillance demonstrated the substantial burden of pandemic influenza in outpatient settings and especially in children aged 2–17 years. Observed trends were consistent with established syndromic and virologic systems.

TU-E-BRA-07: Post-Operative Eye Plaque Imaging Using Tomotherapy MVCT

PURPOSE

Intra-operative ultrasound is used to verify the positioning of episcleral eye plaques used to treat ocular melanoma. Ultrasound can be ambiguous because of image artifacts, and plaques may shift position after surgery. Ultrasound verification is particularly challenging for anterior tumors. Post-operative imaging could be used to trigger interventions that would prevent local treatment failure. We investigated if, and under what conditions, the Tomotherapy megavoltage computed tomography (MVCT) system could be used to perform post-implantation verification of eye plaque positioning.

METHODS

Plaques were placed on a preserved cow's eye, and imaged with the megavoltage CT of a Tomotherapy linear accelerator (Accuray, Sunnyvale, CA). The images were visually and quantitatively assessed to determine if they were of sufficient quality to verify tumor coverage and plaque tilt with respect to the sclera. We used the visibility of the lens as a proxy for visibility of a tumor. To test the utility of hypothetical higher beam current Tomotherapy images, we averaged sequential images of the same setup.

RESULTS

The plaque, the lens of the eye, and the globe are visible in the images. The CNR of the lens with respect to the vitreous was 5.6 for a single image. For 10 images averaged, the CNR was 9.2. Estimated dose from a single image was 1.3 cGy (body CTDIvol); even 10 times this dose would be an acceptable image-guidance dose for radiotherapy patients. One limitation of the imaging procedure is the long scan time (up to 240 seconds), during which time any significant patient motion would lead to image artifacts. Human trials on eye plaque patients are planned.

CONCLUSIONS

Tomotherapy MVCT imaging could be used to verify tumor coverage and plaque tilt after episcleral plaque implantation. Tumors should be visible in standard Tomotherapy images but higher beam current images would be preferred if available.

TU-E-BRA-06: Evaluation of a New MV X-Ray Detector Designed for the TomoTherapy® System

PURPOSE

To evaluate the performance of a new MV X-ray detector prototype specifically designed for use on the TomoTherapy® System.

METHODS

A gas-filled detector array, similar in concept to existing TomoTherapy detector arrays, has been designed and fabricated for the TomoTherapy System. Unlike existing detector arrays, the prototype detector array has a radius of curvature that matches the source-to-detector distance. Also, the internal structure of the detector such as the septa material and geometry has been optimized for MV X-rays. The prototype detector performance was assessed by measuring the signal properties of each of the detector channel signals. Signal, noise, and signal-to-noise ratios (SNR) were measured. Finally, the resulting MVCT image quality was assessed.

RESULTS

The signal profile across the prototype detector more closely matches the incident X-ray beam intensity and, in particular, is missing the characteristic trough in the center of signal profiles from existing TomoTherapy detector arrays. Compared to an existing detector, the mean signal is approximately equal outside the central region. Inside the 100 central channels (out of 576 total channels), the prototype detector signal is substantially larger than the existing detector. The variation in the pulse-to-pulse signal (noise), after accounting for output fluctuations, is substantially lower with the new detector. The resulting SNR is an average of 18% higher across all channels, with an improvement of up to 36% for the central channels. The prototype detector yielded MVCT images that, compared to one typical system with an existing detector array, had 7% lower image noise in the periphery and 36% lower noise at the center of the image.

CONCLUSIONS

This evaluation indicates that the performance of a new MV X-ray detector array prototype exceeds the performance of an existing detector array in terms of signal-to-noise ratio and resulting MVCT image quality.

Laparoscopic sleeve gastrectomy for obesity: can it be considered a definitive procedure?

BACKGROUND

Providing bariatric surgery services to an inner-city population is a challenge. Laparoscopic sleeve gastrectomy (LSG) is an effective operation for morbid obesity with a relatively low complication rate. LSG appears to be a suitable alternative procedure for this group of patients.

METHODS

This is a retrospective review and analysis of the experience with 185 consecutive LSGs that had completed at least 6 months follow-up. Eleven conversions from LSG to laparoscopic Roux-en-Y gastric bypass were excluded, leaving 174 patients for outcome analysis. Data collected were patient demographics, body mass index (BMI), comorbid conditions, operating time, length of hospital stay, and perioperative complications. Weight loss and resolution/improvement of comorbidities were analyzed.

RESULTS

Mean patient age was 39.58 years and mean BMI was 48.97 kg/m(2). The percentage of patients with BMI > 50 kg/m(2) was 37.94%. Mean excess weight loss (EWL) was 44.76, 55.52, 59.22, and 58.92% at 6, 12, 24, and 36 months, respectively. Six patients (3.24%) lost less than 25% EWL. Thirteen patients (7.02%) regained an average of 13 lb after reaching a plateau. Resolution/improvement of comorbidities was 84% for diabetes mellitus, 49.99% for hypertension, 90% for asthma, 90.74% for obstructive sleep apnea, and 45.92% for gastroesophageal reflux disease symptoms (GERD). The mortality rate was zero in this series. Perioperative complications occurred in 26 patients (14.05%): four staple-line leaks (2.16%), four bleeds (2.16%), four obstructions (2.16%), five vomiting/dehydration (2.70%), six new onset of GERD symptoms (3.24%), two with pneumonia (1.08%), and one with pulmonary embolism (0.54%).

CONCLUSION

LSG results in stable and adequate weight loss with resolution/improvement in comorbidities in a high percentage of patients. It can be considered a definitive operation for morbid obesity.

A slit method to determine the focal spot size and shape of TomoTherapy system

PURPOSE

To obtain accurate x-ray source profile measurements using a slit-collimator, the slit-collimator should have a narrow width, large height, and be positioned near the source. However, these conditions may not always be met. In this paper, the authors provide a detailed analysis of the slit measurement geometry and the relationship between the slit parameters and the measured x-ray source profile. The slit model allows the use of a shorter and more easily available slit-collimator, while accurate source profile measurements can still be obtained.

METHODS

Measurements were performed with a variety of slit widths and/or slit to source distances. The relationship derived between the slit parameters and the measured profile was used to determine the true focal spot profile through a least square fit of the profile data. The model was verified by comparing the predicted profiles at a variety of slit-collimator parameters with the measured results on the TomoTherapy Hi-Art system.

RESULTS

Both the treatment beam and the imaging beam were measured. For treatment mode, it was found that a source consisting of one Gaussian with a 0.75 mm full-width-half-maximum (FWHM) and 72% peak amplitude and a second Gaussian with a 2.27 mm FWHM and 18% peak amplitude matched measurement profiles. The overall source profile has a FWHM of 0.93 mm, but with a higher amplitude in the tail region than a single Gaussian. For imaging mode, the source consists of one Gaussian with a 0.68 mm FWHM and 82% peak amplitude and a second Gaussian with a 1.83 mm FWHM and 18% peak amplitude. The overall source profile has a FWHM of 0.77 mm.

CONCLUSIONS

Our study of the focal spot measurement using slit-collimators showed that accurate source profile measurements can be achieved through fitting of measurement results at different slit widths and source-to-slit distances (SSD). Quantitative measurements of the TomoTherapy linac focal spot showed that the source distribution could be better described with a model consisting of two Gaussian components rather than a single Gaussian model as assumed in previous studies.

Effects of intensive insulin therapy alone and with added pioglitazone on renal salt/water balance and fluid compartment shifts in type 2 diabetes

OBJECTIVE

To evaluate the effects of intensive insulin therapy alone or with added pioglitazone on renal salt/water balance and body fluid compartment shifts in type 2 diabetes.

METHODS

A total of 25 insulin-treated, obese patients with type 2 diabetes were randomized to pioglitazone 45 mg (n = 12) or placebo (n = 13) and treated intensively for 12-16 weeks to achieve equivalent glycaemic control. We measured total body water (TBW) and extracellular/intracellular fluid by bioimpedance analysis; plasma/RBC volume with I(131)albumin; sodium handling by fractional excretion of sodium/lithium (FeNa/FeLi) and other renal/hormonal parameters.

RESULTS

Intensification of insulin therapy and the addition of pioglitazone significantly improved glycaemia (HbA1C 7.8-7.2% and 7.6-7.1%) and increased body weight (1.7 and 4.9 kg) respectively. TBW increased 1.7 l with insulin alone (65% intracellular) and 1.6 l with added pioglitazone (75% extracellular) (p = 0.06 and 0.09 respectively). Plasma volume increased 0.2 +/- 0.1 l with insulin alone (p = 0.05) and 0.4 +/- 0.1 l with added pioglitazone (p < 0.05). Extravascular, extracellular (interstitial) fluid increased significantly and more with added pioglitazone (0.8 +/- 0.2 l, p < 0.01) than with insulin alone (0.4 +/- 0.2 l, p = ns). At steady-state, FeLi (marker of proximal-tubular sodium delivery to the distal nephron) increased significantly with added pioglitazone (12.4 +/- 1.3 to 18.0 +/- 3.2%) vs. no significant change with insulin alone (15.4 +/- 1.2 to 14.5 +/- 2.3%). There were no significant changes in the other parameters.

CONCLUSION

In intensively insulin-treated obese type 2 diabetic patients, at equivalent glycaemic control, the addition of pioglitazone causes greater weight gain, but a similar increase in body water that is mainly extracellular and interstitial compared with intracellular increase with insulin therapy alone. Pioglitazone also increases the filtered load of sodium reabsorbed at the distal nephron with no net change in FeNa.