Point of Care Ultrasound to Identify Diaphragmatic Dysfunction after Thoracic Surgery.

BACKGROUND: Postoperative diaphragmatic dysfunction after thoracic surgery is underestimated due to the lack of reproducible bedside diagnostic methods. We used point of care ultrasound to assess diaphragmatic function bedside in patients undergoing video-assisted thoracoscopic or thoracotomic lung resection. Our main hypothesis was that the thoracoscopic approach may be associated with lower incidence of postoperative diaphragm dysfunction as compared to thoracotomy. Furthermore, we assessed the association between postoperative diaphragmatic dysfunction and postoperative pulmonary complications. METHODS: This was a prospective observational cohort study. Two cohorts of patients were evaluated: those undergoing video-assisted thoracoscopic surgery versus those undergoing thoracotomy. Diaphragmatic dysfunction was defined as a diaphragmatic excursion less than 10 mm. The ultrasound evaluations were carried out before (preoperative) and after (i.e., 2 h and 24 h postoperatively) surgery. The occurrence of postoperative pulmonary complications was assessed up to 7 days after surgery. RESULTS: Among the 75 patients enrolled, the incidence of postoperative diaphragmatic dysfunction at 24 h was higher in the thoracotomy group as compared to video-assisted thoracoscopic surgery group (29 of 35, 83% vs. 22 of 40, 55%, respectively; odds ratio = 3.95 [95% CI, 1.5 to 10.3]; P = 0.005). Patients with diaphragmatic dysfunction on the first day after surgery had higher percentage of postoperative pulmonary complications (odds ratio = 5.5 [95% CI, 1.9 to 16.3]; P = 0.001). Radiologically assessed atelectasis was 46% (16 of 35) in the thoracotomy group versus 13% (5 of 40) in the video-assisted thoracoscopic surgery group (P = 0.040). Univariate logistic regression analysis indicated postoperative diaphragmatic dysfunction as a risk factor for postoperative pulmonary complications (odds ratio = 5.5 [95% CI, 1.9 to 16.3]; P = 0.002). CONCLUSIONS: Point of care ultrasound can be used to evaluate postoperative diaphragmatic function. On the first postoperative day, diaphragmatic dysfunction was less common after video-assisted than after the thoracotomic surgery and is associated with postoperative pulmonary complications.

Nutritional adequacy according to carbohydrates and fat quality.

PURPOSE: To investigate the association between carbohydrate quality, fat quality or adherence to the Mediterranean diet and intake adequacy of 19 micronutrients in the PREDIMED (PREvención con DIeta MEDiterránea) trial, a multicenter, randomized, controlled, parallel group and primary prevention trial conducted in Spain. METHODS: We assessed baseline dietary intake of 6,542 elderly subjects at high cardiovascular risk through a validated food frequency questionnaire (FFQ) and a validated 14-item Mediterranean diet (Med-diet) score. We used a multidimensional carbohydrate quality index (CQI) using four criteria and a fat quality index (FQI) according to the ratio (MUFA + PUFA)/(SFA + TFA). The probability of intake adequacy was calculated comparing the intakes to DRI, and also using the probabilistic approach. Absolute and adjusted probability of having inadequate intake for either ≥6 DRI or ≥8 DRI were estimated to assess nutritional adequacy according to quintiles of each index. RESULTS: The lowest prevalence of inadequate micronutrient intake (≥8 DRI) was found in the highest quintile of CQI or Med-diet score, and in the lowest quintile of FQI (adjusted fold risk: 1.4, 3.4 and 10.2 respectively in comparison with the lowest quintile). P for trend <0.001 in three multivariable models. A higher CQI or Med-Diet score and a lower FQI were significantly associated with a lower fold risk of unmet EAR values. CONCLUSIONS: A multidimensional assessment of CQI can be a useful tool to evaluate the quality of carbohydrates. This score and a 14-item Med-diet score were positively related to overall micronutrient adequacy in elderly participants.

Colorectal cancer in aged patients. Toward the routine treatment through laparoscopic surgical approach.

AIM: Colorectal cancer is one of the most common malignancies in general population. The incidence seems to be higher in older age. Surgery remains the treatment of choice and laparoscopic approach offers numerous benefits. We report our personal experience in elderly patients operated on for colorectal cancer with laparoscopic resection. PATIENTS AND METHODS: From January 2003 to September 2013, out of 160 patients aged 65 years or older and operated with minimally invasive techniques, 30 cases affected by colorectal cancer and operated on with laparoscopic approach were analyzed in this study. RESULTS: Male/female ratio was 1.35 and mean age 72 years. Constipation, weight loss, anemia and rectal bleeding were the most commonly reported symptoms. Lesions involved descending-sigmoid colon in 53% of cases, rectum in 37% and ascending colon in 10%. Among laparoscopic colo-rectal operations laparoscopic left colectomy was the most frequently performed, followed by right colectomy, abdominoperineal resection and Hartmann procedure. Operative times ranged from 3 to 5 hours depending on surgical procedure performed. Mean hospital stay was 6 days (range 4-9). Conversion to open approach occurred only in a case of laparoscopic right colectomy (3%) for uncontrolled bleeding. A single case of mortality was reported. In two cases (7%) anastomotic leakage was observed, conservatively treated in one patient and requiring reoperation in the other one. CONCLUSIONS: Laparoscopic colorectal surgery is feasible and effective for malignancies in elderly population offering several advantages including immunologic and oncologic ones. However an experienced surgical team is essential in reducing risks and complications.

Non-invasive ventilation after surgery in amyotrophic lateral sclerosis.

BACKGROUND: Surgery in patients affected by amyotrophic lateral sclerosis (ALS) presents a particular anesthetic challenge because of the risk of post-operative pulmonary complications. AIMS OF THE STUDY: We report on the use of non-invasive ventilation (NIV) to prevent post-operative pulmonary complications (PPCs) in nine patients affected by ALS enrolled in a phase-1 clinical trial with stem cell transplantation. METHODS: All patients were treated with autologous mesenchymal stem cells implanted into the spinal cord with a surgical procedure. Anesthesia was induced with propofol and maintained with remifentanil and sevoflurane. No muscle relaxant was used. After awakening and regain of spontaneous breathing, patients were tracheally extubated. Non-invasive ventilation through nasal mask was delivered and non-invasive positive pressure ventilation and continuous positive pressure ventilation were started. RESULTS: The average time on NIV after surgery was 3 h and 12 min. All patients regained stable spontaneous breathing after NIV discontinuation and had no episodes of respiratory failure until the following day. CONCLUSIONS: Our case series suggest that the use of NIV after surgery can be a safe strategy to prevent PPCs in patients affected by ALS. The perioperative procedure we chose for these patients appeared safe even in patients with advanced functional stage of the disease.

High-dose rocuronium for rapid-sequence induction and reversal with sugammadex in two myasthenic patients.

The anesthetic management of patients affected by myasthenia gravis is usually challenging in elective surgery and even more so in emergency procedures. The difficulties involved are several-fold, ranging from the choice of an appropriate muscle relaxant (i.e. one that enables safe and rapid airway management) to neuromuscular monitoring and normal muscular recovery. Additionally, optimizing patient conditions - either pharmacologically or with plasmapheresis - before intervention is well beyond the realm of possibility. We discuss the anesthetic management of two myasthenic patients undergoing emergency surgery (for sigmoid perforation and upper gastrointestinal bleeding respectively). In both cases, we opted for rapid-sequence induction with high-dose rocuronium to prevent inhalation of gastric contents. We also report on the implication of neuromuscular monitoring. We found that the rocuronium-sugammadex combination was a useful and effective option in the emergency setting.

Development of clinical tools to estimate the breathing effort during high-flow oxygen therapy: A multicenter cohort study.

INTRODUCTION AND OBJECTIVES: Quantifying breathing effort in non-intubated patients is important but difficult. We aimed to develop two models to estimate it in patients treated with high-flow oxygen therapy. PATIENTS AND METHODS: We analyzed the data of 260 patients from previous studies who received high-flow oxygen therapy. Their breathing effort was measured as the maximal deflection of esophageal pressure (ΔPes). We developed a multivariable linear regression model to estimate ΔPes (in cmH2O) and a multivariable logistic regression model to predict the risk of ΔPes being >10 cmH2O. Candidate predictors included age, sex, diagnosis of the coronavirus disease 2019 (COVID-19), respiratory rate, heart rate, mean arterial pressure, the results of arterial blood gas analysis, including base excess concentration (BEa) and the ratio of arterial tension to the inspiratory fraction of oxygen (PaO2:FiO2), and the product term between COVID-19 and PaO2:FiO2. RESULTS: We found that ΔPes can be estimated from the presence or absence of COVID-19, BEa, respiratory rate, PaO2:FiO2, and the product term between COVID-19 and PaO2:FiO2. The adjusted R2 was 0.39. The risk of ΔPes being >10 cmH2O can be predicted from BEa, respiratory rate, and PaO2:FiO2. The area under the receiver operating characteristic curve was 0.79 (0.73-0.85). We called these two models BREF, where BREF stands for BReathing EFfort and the three common predictors: BEa (B), respiratory rate (RE), and PaO2:FiO2 (F). CONCLUSIONS: We developed two models to estimate the breathing effort of patients on high-flow oxygen therapy. Our initial findings are promising and suggest that these models merit further evaluation.

Electromagnetic navigation bronchoscopy and rapid on site evaluation added to fluoroscopy-guided assisted bronchoscopy and rapid on site evaluation: improved yield in pulmonary nodules.

AIM: Electromagnetic navigation bronchoscopy (ENB) was reported to increase diagnostic yield in pulmonary nodules (PNs). The aim of this study was to assess if rapid on site evaluation (ROSE) associated with ENB could improve diagnostic accuracy in PNs after non-diagnostic fluoroscopy-guided bronchoscopy added to ROSE. METHODS: Forty patients with PNs suspected for lung cancer underwent to ENB + ROSE after non-diagnostic Fluoroscopy-guided Bronchoscopy + ROSE. Each lesion was studied with reference to size, location, presence of bronchus sign on CT. All lesions were sampled by needle and brush; if negative, by forceps and bronchoalveolar lavage. All patients were followed-up until achievement of definitive diagnosis. RESULTS: Twenty-nine out of 41 lesions (70.7%) had a definitive diagnosis. ENB sensitivity for malignancy was 76.5%, with higher rate in presence of bronchus sign on CT (86.2%) and in case of lesions located in the upper and middle lobes (87.5%). CONCLUSION: ENB is a useful tool in the evaluation of PNs. High diagnostic accuracy may be related to sampling (transbronchial needle aspiration), ROSE, location and presence of bronchus sign.

Laparoscopic-endoscopic rendez-vous resection of iuxta-cardial gastric GIST.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and they often require a surgical removal. Gastrointestinal stromal tumors can originate from any part of the gastrointestinal tract but gastric location is the most common. In the past the risk of rupture of pseudocapsula and peritoneal dissemination have discouraged surgeons from making a minimally invasive surgical treatment. Recently laparoscopic wedge resection has been proposed. Performance of this mini-invasive technique is however difficult in some gastric location of gastrointestinal stromal tumors, such as iuxta-cardial region. The Authors report and discuss a new technique they used to remove a gastrointestinal stromal tumor located just below the cardia, using a rendez-vous endoscopic and laparoscopic technique.

Provision of trauma care in asymmetric warfare: a conceptual framework to support the decision to implement frontline care services.

INTRODUCTION: The emerging trends of asymmetric and urban warfare call for a revision of the needs and the way in which frontline trauma care is provided to affected population. However, there is no consensus on the process to decide when and how to provide such lifesaving interventions in form of Trauma Stabilization Point (TSP). METHODS: A three-step Delphi method was used to establish consensus. A focus group discussion was convened to propose a framework and develop the list of twenty-one (21) statements for validation of a group of experts. RESULTS: A panel of twenty-eight (28) experts reviewed the statements and participated to both first and second rounds. Comments and recommendations provided by the FGD and during round 1 were used to analyze the findings of the study. The proposed framework includes five main categories identified as interconnected components that facilitate the decision to implement or not the TSP. A total of sixteen (16) elements distributed across the five categories have been considered as being able to guide the decision to utilize such capability in high-risk security and resource constrained settings. CONCLUSION: The TSP has the potential to prevent death and disability. The proposed framework and categories add a structure to the decision-making process and represents an important step to support emergency and trauma care planning and implementation efforts.

Not only for caregivers: intranasal glucagon for severe hypoglycaemia in a simulation study.

AIMS: To evaluate: (i) the propensity of paediatrics and emergency medicine residents to select different therapeutic options and (ii) the speed and administration success in a high-fidelity simulation of severe hypoglycaemia in a child with type 1 diabetes (T1DM). METHODS: In this single-centre high-fidelity simulation study, 51 paediatrics or emergency medicine residents were exposed to a scenario of severe hypoglycaemia in a T1DM child attending an ambulatory setting, before and after a training on the preparation and administration of both injectable and IN glucagon. Time for drug delivery and its effectiveness were collected. RESULTS: Before training, 45.1% of participants chose to administer injectable glucagon, 43.1% intravenous glucose solution, 5.9% intranasal (IN) glucagon, and 5.9% took no action. Administration was successful in 74% of injectable glucagon, 33.3% intravenous glucose solution, and 22.7% IN glucagon. After training, 58.8% of participants chose IN and 41.2% injectable glucagon, with 100% of successful administrations for IN glucagon and 90.5% for injectable glucagon. Time to successful administration was shorter for IN than injectable glucagon (23 ± 10 vs. 38 ± 7 s, p < 0.0001). CONCLUSIONS: IN glucagon is an easy and effective option for severe hypoglycaemia treatment, with an almost zero possibility of failure provided that adequate training is imparted.

Predictors of intubation in COVID-19 patients treated with out-of-ICU continuous positive airway pressure.

BACKGROUND: As delayed intubation may worsen the outcome of coronavirus disease 2019 (COVID-19) patients treated with continuous positive airway pressure (CPAP), we sought to determine COVID-specific early predictors of CPAP failure. METHODS: In this observational retrospective multicentre study, we included all COVID-19 patients treated with out-of-ICU CPAP, candidates for intubation in case of CPAP failure. From these patients, we collected demographic and clinical data. RESULTS: A total of 397 COVID-19 patients were treated with CPAP for respiratory failure, with the therapeutic goal of providing intubation in case of CPAP failure. Univariable analysis showed that, age, lactate dehydrogenase (LDH) and white cell counts were all significantly lower in patients with successful CPAP treatment compared to those failing it and undergoing subsequent intubation. The percentage changes between baseline and CPAP application in the ratio of partial pressure arterial oxygen (PaO2) and fraction of inspired oxygen (FiO2), PaO2, respiratory rate and ROX index were higher in patients experiencing successful CPAP compared to those failing it. FiO2 and male gender were also significantly associated with intubation. Multivariable analysis adjusting for age, gender, Charlson comorbidity index, percentage change in PaO2/FiO2 or PaO2 and FiO2 separately, lactate, white blood cell count, LDH and C-reactive protein levels led to an area under the curve of 0.818 and confirmed that age, LDH and percentage increase in PaO2/FiO2 are predictors of intubation. CONCLUSIONS: In COVID-19 patients requiring CPAP, age, LDH and percentage change in PaO2/FiO2 after starting CPAP are predictors of intubation.

Sleep disorders in adult-onset myotonic dystrophy type 1: a controlled polysomnographic study.

BACKGROUND: Sleep disturbances and excessive daytime somnolence are common and disabling features in adult-onset myotonic dystrophy type 1 (DM1). METHODS: Our study used questionnaires, ambulatory polysomnography and the multiple sleep latency test to evaluate sleep-wake cycle and daytime sleepiness in unselected adult-onset DM1 patients. We recruited 18 patients affected by adult-onset DM1 and 18 matched controls. RESULTS: Sleep efficiency was <90% in 16/18 patients, and it was significantly reduced when compared with controls. Reduced sleep efficiency was associated with abnormal respiratory events (5/18 patients) and/or periodic limb movements (11/18 patients). The Periodic Limb Movement Index was significantly increased in DM1 versus controls. A significantly lower mean MSLT sleep latency was detected in DM1 versus controls, but it did not reach pathological levels. CONCLUSIONS: Our controlled study demonstrated sleep alterations in unselected consecutive DM1 patients. Periodic limb movements in sleep are commonly associated with sleep disturbance in adult-onset DM1, and it may represent a marker of CNS neurodegenerative processes in DM1.

Total polyphenol excretion and blood pressure in subjects at high cardiovascular risk.

BACKGROUND AND AIMS: Dietary factors are critical for the prevention and treatment of hypertension, but data on the effects of specific nutrients on blood pressure (BP) are scarce. The aim of this study was to assess the relationship between total polyphenol excretion (TPE) in urine, as an objective measurement of total polyphenol intake and BP in an elderly population at high cardiovascular risk. METHODS AND RESULTS: Cross-sectional substudy of 589 high-risk participants entering in the PREDIMED trial. BP was measured and TPE was determined in urine by Folin-Ciocalteu assay. A significant positive association was observed between TPE in urine and daily intake of fruit and vegetables (F&V), coffee or wine after adjusting for potential confounders. The intake of 100 g of F&V (Beta=0.150;P<0.001) had a greater contribution to TPE than 100 mL of coffee (Beta=0.141;P=0.001), and the latter two foods contributed more than the consumption of 100 mL of wine (Beta=0.120;P=0.019). An inverse association was observed between urinary TPE and the prevalence of hypertension. Participants in the highest quartile of urinary TPE had a reduced prevalence of hypertension compared to those in the lowest quartile (Odds Ratio=0.64; 95% confidence interval 0.45 to 0.92; P=0.015). Systolic and diastolic BP were inversely associated with urinary TPE after adjustment for potential confounders (P=0.024 and P=0.003, respectively). CONCLUSIONS: Polyphenol intake, assessed via TPE in urine, was negatively associated with BP levels and prevalence of hypertension in an elderly Mediterranean population at high cardiovascular risk. Participants with the highest intake of polyphenol-rich foods showed the lowest BP measurements.

Pregabalin as add-on therapy induces REM sleep enhancement in partial epilepsy: a polysomnographic study.

BACKGROUND AND PURPOSE: To evaluate the effects of pregabalin (PGB) adjunctive therapy on sleepwake cycle and daytime somnolence in adult patients affected by partial epilepsy. METHODS: Twelve patients affected by partial epilepsy underwent a 24-h ambulatory polysomnography and a subjective evaluation of daytime somnolence by means of the Epworth Sleepiness Scale (ESS), before and after 3 months treatment with PGB. RESULTS: Pregabalin therapy reduced seizures by >50% in 8 out of 12 patients. It induced a significant increase of REM sleep and a decrease of stage 2 NREM sleep (S2). A significant increase of the ESS score was observed without reaching the pathological cut-off value (mean ESS score <10). No statistical correlation between REM sleep and seizure frequency was observed. DISCUSSION: Pregabalin seems to be effective and safe in partial epilepsy. The increase of REM sleep may be indicative of an improvement of nocturnal sleep quality considering the involvement of REM sleep in learning and memory processes. REM sleep enhancement may be the result of both a direct effect of PGB on sleep generators and an indirect effect due to its clinical efficacy. The increase of ESS score within normal range suggests that daytime somnolence is a minor adverse effect of PGB.

Thoracic epidural analgesia in post-thoracotomy patients: comparison of three different concentrations of levobupivacaine and sufentanil.

BACKGROUND: Relative effects of dosage, volume and concentration of local anaesthetics used for postoperative thoracic epidural analgesia are still under debate. In this randomized, prospective, double-blinded study, we evaluated the incidence of side-effects such as changes in arterial pressure, postoperative nausea, vomiting, and pruritus in patients admitted for thoracic surgery during continuous thoracic epidural infusion using levobupivacaine and sufentanil mixture in three different volumes. METHODS: We studied 150 patients who underwent thoracotomy with a thoracic epidural catheter placed between T4 and T7. The patients were randomized into three groups which received 10 mg h(-1) of levobupivacaine at three different concentrations (0.5%, 0.25%, and 0.15%), in combination with sufentanil at 2.6 microg h(-1). Haemodynamic effects, pruritus, nausea, vomiting, sensory and motor block, pain score, additional analgesic requirement, sedation, and patient satisfaction were registered immediately after the surgical operation and on the first, second, and third postoperative days. RESULTS: We did not detect any differences in the incidence of side-effects such as changes in arterial pressure, and also postoperative nausea, vomiting, and pruritus. The three groups were also similar with regard to patient characteristics, sensory and motor block, pain score, analgesic rescue dose, sedation, and patient satisfaction. CONCLUSIONS: The same dose of a mixture of levobupivacaine and sufentanil administered in three different volumes and concentrations during continuous thoracic epidural infusion for thoracotomy provided an equal incidence of adverse haemodynamic effects, nausea, vomiting, or pruritus.

Multivariate explanatory model for sporadic carcinoma of the colon in Dukes' stages I and IIa.

OBJECTIVE: We obtained before an explanatory model with six dependant variables: age of the patient, total cholesterol (TC), HDL cholesterol (HDL-C), VLDL cholesterol (VLDL-C), alkaline phosphatase (AP) and the CA 19.9 tumour marker. Our objective in this study was to validate the model by means of the acquisition of new records for an additional analysis. DESIGN: Non-paired case control study. SETTING: Urban and rural hospitals and primary health facilities in Western Andalusia and Extremadura (Spain). PATIENTS: At both the primary care facilities and hospital level, controls were gathered in a prospective manner (n= 275). Cases were prospective and retrospective manner collected on (n=126). MAIN OUTCOME MEASURES: Descriptive statistics, logistic regression and bootstrap analysis. RESULTS: The AGE (odds ratio 1.02; 95% CI 1.003-1.037) (p= 0.01), the TC (odds ratio 0.986; 95% C.I. 0.980-0.992) (p< 0.001) and the CA 19.9 (odds ratio 1.023; 95% C.I. 1.012- 1.034) (p<0.001) were the variables that showed significant values at logistic regression analysis and bootstrap. Berkson's bias was statistically assessed. CONCLUSIONS: The model, validated by means of logistic regression and bootstrap analysis, contains the variables AGE, TC, and CA 19.9 (three of the original six) and has a level 4 over 5 according to the criteria of Justice et al. (multiple independent validations) [Ann. Intern. Med.1999; 130: 515].

A cultural effect on brain function.

We present behavioral and anatomical evidence for a multi-component reading system in which different components are differentially weighted depending on culture-specific demands of orthography. Italian orthography is consistent, enabling reliable conversion of graphemes to phonemes to yield correct pronunciation of the word. English orthography is inconsistent, complicating mapping of letters to word sounds. In behavioral studies, Italian students showed faster word and non-word reading than English students. In two PET studies, Italians showed greater activation in left superior temporal regions associated with phoneme processing. In contrast, English readers showed greater activations, particularly for non-words, in left posterior inferior temporal gyrus and anterior inferior frontal gyrus, areas associated with word retrieval during both reading and naming tasks.

Simulation of a hospital disaster plan: a virtual, live exercise.

INTRODUCTION: Currently, there is no widely available method to evaluate an emergency department disaster plan. Creation of a standardized patient database and the use of a virtual, live exercise may lead to a standardized and reproducible method that can be used to evaluate a disaster plan. PURPOSE: A virtual, live exercise was designed with the primary objective of evaluating a hospital's emergency department disaster plan. Education and training of participants was a secondary goal. METHODS: A database (disastermed.ca) of histories, physical examination findings, and laboratory results for 136 simulated patients was created using information derived from actual patient encounters. The patient database was used to perform a virtual, live exercise using a training version of the emergency department's information system software. RESULTS: Several solutions to increase patient flow were demonstrated during the exercise. Conducting the exercise helped identify several faults in the hospital disaster plan, including outlining the important rate-limiting step. In addition, a significant degree of under-triage was demonstrated. Estimates of multiple markers of patient flow were identified and compared to Canadian guidelines. Most participants reported that the exercise was a valuable learning experience. CONCLUSIONS: A virtual, live exercise using the disastermed.ca patient database was an inexpensive method to evaluate the emergency department disaster plan. This included discovery of new approaches to managing patients, delineating the rate-limiting steps, and evaluating triage accuracy. Use of the patient timestamps has potential as a standardized international benchmark of hospital disaster plan efficacy. Participant satisfaction was high.

Accuracy of computer simulation to predict patient flow during mass-casualty incidents.

INTRODUCTION: Although most hospitals have an emergency department disaster plan, most never have been implemented in a true disaster or been tested objectively. Computer simulation may be a useful tool to predict emergency department patient flow during a disaster. PURPOSE: The aim of this study was to compare the accuracy of a computer simulation in predicting emergency department patient flow during a mass-casualty incident with that of a real-time, virtual, live exercise. METHODS: History, physical examination findings, and laboratory results for 136 simulated patients were extracted from the disastermed.ca patient database as used as input into a computer simulation designed to represent the emergency department at the University of Alberta Hospital. The computer simulation was developed using a commercially available simulation software platform (2005, SimProcess, CACI Products, San Diego CA). Patient flow parameters were compared to a previous virtual, live exercise using the same data set. RESULTS: Although results between the computer simulation and the live exercise appear similar, they differ statistically with respect to many patient benchmarks. There was a marked difference between the triage codes assigned during the live exercise and those from the patient database; however, this alone did not account for the differences between the patient groups. It is likely that novel approaches to patient care developed by the live exercise group, which are difficult to model by computer software, contributed to differences between the groups. Computer simulation was useful, however, in predicting how small changes to emergency department structure, such as adding staff or patient care areas, can influence patient flow. CONCLUSIONS: Computer simulation is helpful in defining the effects of changes to a hospital disaster plan. However, it cannot fully replace participant exercises. Rather, computer simulation and live exercises are complementary, and both may be useful for disaster plan evaluation.