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In an attempt to further standardize surgical training, the American Board of Surgery now requires that residents provide evidence that they are certified in flexible endoscopy. This prospective study was designed to determine whether, through a structured curriculum, junior level residents could learn to conduct competent and safe screening colonoscopy (SC). An Institutional Review Board-approved prospective analysis of SC performed by five postgraduate year-2 residents during the 2012–2013 academic year was completed. All SC were performed under direct supervision of one of the two surgical endoscopists after each resident passed a structured endoscopy simulation curriculum. The following metrics of the American Society for Gastrointestinal Endoscopy and the American College of Gastroenterology were recorded: bowel prep quality; cecal intubation; withdrawal time; number of visualized polyps; procedural duration; final pathology; adenoma detection rate (ADR); and, complications. Power analysis revealed that 108 procedures were required for an 80 per cent probability of data analysis accuracy. (American Society for Gastrointestinal Endoscopy ASGE/American College of Gastroenterology benchmark values in parentheses): 166 colonoscopies were performed, of which 149 met inclusion criteria. Bowel prep was considered “excellent” or “good” in 90 per cent of cases. The cecum was reached in 96 per cent of cases. Mean withdrawal time was 12 minutes (≥6 minute). Average procedure time was 30 minutes (≤ 30 minute). Polyp(s) were visualized and removed in 30 per cent of patients. The overall adenoma detection rate was 22.8 per cent (>20%). The ADR for males was 29.5 per cent (>25%). The ADR for females was 18.2 per cent (>15%). Average polyp size was 7.7 mm (range: 2–25 mm). No patients were readmitted for bleeding or perforation. Within a structured learning environment, trained surgical endoscopists can teach junior level surgery residents to perform safe and competent screening colonoscopy.

The American Society for Gastrointestinal Endoscopy (ASGE)/American College of Gastroenterology Task Force (ACGTF) on Quality in Endoscopy released updated quality benchmarks for colonoscopy in 2015. Our initial study concluded that surgery residents could perform safe and competent screening colonoscopy within a structured endoscopy curriculum. In this follow-up study, we sought to determine whether surgery residents could achieve the increased adenoma detection rate (ADR) benchmarks endorsed by the ASGE/ACGTF. An Institutional Review Board-approved prospective analysis of colonoscopies performed by five postgraduate year 2 and 3 general surgery residents from 2013 to 2015 was completed. All colonoscopies were performed under the direct supervision of surgical endoscopists after each resident passed a structured endoscopy simulation curriculum. The following ASGE/ACG quality metrics were recorded: bowel preparation quality; cecal intubation rate; polyp and ADRs; and, complications. Power analysis determined that 108 procedures were required for an 80 per cent probability of data analysis accuracy. About 135 screening and diagnostic colonoscopies were performed. Bowel prep was considered "adequate" in 90 per cent of cases. The cecum was reached independently in 95 per cent of cases. Polyp(s) were visualized and removed in 39 per cent of patients. The overall ADR was 31.8 per cent (25%). Male ADR was 38.7 per cent (30%). Female ADR was 26.0 per cent (20%). Average polyp size was 8.7 mm (range: 1-22 mm). One patient was readmitted for postpolypectomy syndrome, and successfully managed nonoperatively. In conclusion, using our structured endoscopy curriculum, surgery residents achieved ADRs fully consistent with the updated benchmark values endorsed by the ASGE/ACGTF.

Object Although fatigue and its effects on surgical proficiency have been an actively researched area, previous studies have not examined the effect of fatigue on neurosurgery residents specifically. This study aims to quantify the effect of fatigue on the psychomotor and cognitive skills of neurosurgery residents. Methods Seven neurosurgery residents performed a minimum of 3 and a maximum of 4 sessions of 6 surgical exercises precall and postcall. The simulation exercises were designed to measure a surgeon's cognitive abilities, such as memory and attention, while performing simulated surgical tasks and exercises that have been previously validated in several studies, including studies measuring the impact of fatigue on general surgery residents. Each exercise measured tool-movement smoothness, time elapsed, and cognitive errors. The change in surgical skills in precall and postcall conditions was assessed by means of an ANOVA, with p < 0.05 considered statistically significant. Results The neurosurgery residents did not show a statistically significant difference in their surgical skills between the pre- and postcall states (p < 0.3, p < 0.4, and p < 0.2 for movement smoothness, time elapsed, and cognitive errors, respectively). The mean decrement for all residents in the postcall condition was 13.1%. Conclusions Postcall fatigue is associated with a marginal decrease in proficiency during simulated surgery in neurosurgery residents. In a similar study, general surgery residents showed a statistically significant decrement of 27.3% in the postcall condition. The impact of fatigue on different specialties should be further investigated prior to implementation of a national physician work-hour policy.

To gain additional insight into the impact of fatigue on surgery resident proficiency, we set out to quantify its impact on behavioral and neurophysiologic measures.Simulations were first created using a visio-haptic joystick attached to a surgical instrument (tool) that allows realistic interactions. Before baseline (pre-call) and after call, 7 PGY1 surgery residents performed simulation tasks that required varying levels of psychomotor and cognitive skill. Residents completed 3 sessions per week for 4 weeks. Surgical proficiency was established using 5 metrics: hand movement smoothness; instrument movement smoothness; time to task completion; gesture level proficiency and cognitive errors. Data (percent change from baseline, pre-call) were analyzed using repeated measures ANOVA. While performing these tasks, the residents also wore an EEG cap (B-Alert; Advanced Brain Monitoring), the data from which provided second to second insight into the effects of workload, distraction, and attention on task performance. Mean (±SD) pre-call and post-call values for each were analyzed using repeated measures ANOVA.Residents experienced significant (p0.014) post-call erosions in surgical proficiency, punctuated by dramatic increases in cognitive errors. EEG-based attention scores showed a significant (p0.014) concomitant decrement of 40%; distraction/drowsiness scores increased by 91%; and workload score increased by 51%.Fatigue adversely affects PGY1 resident surgical proficiency and neurophysiologic performance.

BACKGROUND: It is unknown whether surgical residents who learn minimal-access surgery skills in an unstructured environment (ie, at home), will develop a technical skill set that rivals that of those trained in the more traditional, structured learning environment. METHODS: Seven surgery residents were provided structured learning through didactic and hands-on skills training sessions and consistent supervision throughout training. A second group of 7 residents participated in an unstructured learning curriculum of training without supervision. End points were determined at the end of training using a standardized simulator based on predetermined performance measures. RESULTS: Both groups achieved high task scores, with comparable scores on gesture proficiency, hand movement smoothness, instrument movement smoothness, errors, and time elapsed. There was no significant difference between group differences in final skills scores. CONCLUSIONS: Unstructured learning is equally effective in delivering quality skills training when compared with structured training.

Simulation is increasingly being recognized as an important tool in the training and evaluation of surgeons. Currently, there is no simulator that is specific to pediatric minimally invasive surgery (MIS). A fundamental technical difference between adult and pediatric MIS is the degree of motion scaling. Smaller instruments and areas of dissection under greater optical magnification require finer, more precise hand movements. We hypothesized that this can be used to detect differences in skills proficiency between pediatric and general surgeons.We programmed a virtual reality simulation of intracorporeal suturing with modes that used motion scaling to mimic conditions of either adult or pediatric MIS. The participants consisted of pediatric and general surgeons who wore motion-sensing gloves. Metrics included time elapsed, penetration errors, tool movement smoothness, hand movement smoothness, and gesture level proficiency.For all measures, pediatric surgeons demonstrated superior proficiency on exercises conducted in pediatric conditions (P.05). Performance in adult conditions was similar between the 2 groups.Pediatric surgeons possess unique skills compared with general surgeons that relate to the technical challenges they routinely face, reinforcing the need for a surgical simulator specific to pediatric MIS. This validates our simulator and the manipulation of motion scaling as a useful training tool.

While initial results suggest that simulation does promote learning, there is a dearth of studies that define the extent to which skills learned through simulation are retained.Residents skills were measured upon completion of an initial simulation training (baseline scores) and then every month for 6 months. Analysis was also performed to identify the number of iterations of practice required to regain baseline scores.While skill scores did not deteriorate from baseline after the first 3 months (p = 0.61, p = 0.44, p = 0.2, respectively), all scores (except time elapsed) reflected significant deterioration from the fourth month onward (p0.05, p0.032, p0.02). However the number of practice sessions required to regain baseline scores was significantly less than that required to achieve the baseline skill set (p0.0003).Skills learned through simulation show significant deterioration over long periods of time, suggesting that periodic retraining of skills may be necessary to maintain surgical proficiency.

Assuring quality surgical trainees within the confines of reduced work hours mandates reassessment of educational paradigms. Surgical simulators have been shown to be effective in teaching surgical residents, but their use is limited by cost and time constraints. The Nintendo Wii® gaming console is inexpensive and allows natural hand movements similar to those performed in laparoscopy to guide game play. We hypothesize that surgical skills can be improved through take-home simulators adapted from affordable off-the-shelf gaming consoles. A total of 21 surgical residents participated in a prospective, controlled study. An experimental group of 14 surgical residents was assigned to play Marble Mania® on the Nintendo Wii® using a unique physical controller that interfaces with the WiiMote® controller followed by a simulated electrocautery task. Seven residents assigned to the control group performed the electrocautery task without playing the game first. When compared with the control group, the experimental group performed the task with fewer errors and superior movement proficiency ( P < 0.05). The experimental group demonstrated increased ambidexterity with improvement in proficiency of the nondominant hand over time. In conclusion, the Nintendo Wii® gaming device along with Marble Mania® serves as an effective take-home surgical simulator.

BACKGROUND: Patients referred to trauma centers often undergo an extensive diagnostic work-up before transfer. The purpose of our study was to quantify and examine the effects of repeat imaging in this population. METHODS: A prospective cohort study of 410 patient transfers was performed. Repeat imaging was conducted at the discretion of the accepting surgeon for multiple reasons. Two groups were compared, those who did and those who did not require repeat imaging. RESULTS: Overall, 53% of referrals received repeat imaging, at an average cost of $2,985 per patient. This group was older (42 vs 37 y; P < .05), more severely injured (injury severity score, 12 vs 9; P < .05), and experienced longer delays before transfer (244 vs 192 min; P < .05). By using logistic regression analysis, injury severity score was found to be an independent predictor of the need for repeat imaging (P = .003). CONCLUSIONS: Severely injured trauma patients often receive films that ultimately require duplication, resulting in transfer delay, unnecessary morbidity, and increased resource use. Targeted education and development of centralized radiology systems could alleviate some of the burden of unnecessary imaging.

Surgery is a skill-driven discipline. While other high-stake professions with comparable cognitive and psychomotor skill requirements often use warm-up exercises for achieving better proficiency, the effects of such practice have not been investigated sufficiently in surgical tasks.Subjects performed standardized exercises as a preoperative warm-up, after which the standardized exercises were repeated in a randomized order. In a variation to investigate the generalizability of preoperative warm-up, the experimental group was allowed to warm-up with the standardized exercises, after which a different task (electrocautery simulation) was performed. To investigate the effect of warm-up on fatigue, participants were involved in eight sessions (four before night call, four after night call), after which the tasks were repeated. Results were analyzed using ANOVA to plot differences between warm-up and followup condition.All outcomes measures demonstrated statistically significant improvements after all of the post-warm-up exercises (p0.01), and were seen in all groups with differing experience levels. In addition, the simple warm-up exercises led to a significant increase in proficiency in followup electrocautery task for the experimental group when compared with the control group (p0.0001). There was also significant improvement in performance of the fatigued group to approximately baseline performance (p0.05), although they were not able to reach their optimal potential performance.Preoperative warm-up for 15 to 20 minutes with simple surgical exercises leads to a substantial increase in surgical skills proficiency during followup tasks.

Fatigue and sleep deprivation and their effects on surgical proficiency have been actively researched areas. Past studies that have focused solely on residents have provided an important insight into how fatigue affects residents' ability to perform. This study aims to quantify the effect of fatigue on attending surgeons.To quantify the effect of fatigue on psychomotor and cognitive skills of surgical residents and attending surgeons, visiohaptic simulations were created to mimic realistic interactions.Both groups showed a significant decrement in proficiency measures postcall. When tasks were separated based on psychomotor versus cognitive-dominated skills, attending surgeons made 25% fewer (P.05) cognitive errors than residents postcall. Psychomotor skills were equally affected in both groups.Call-associated fatigue is associated with increased error rates in the cognitive skill domain, although less so in attending surgeons compared with their resident counterparts.

Previous studies have explored the effect of fatigue on general psychomotor proficiency. However, studies specifically addressing the effect of fatigue on surgical residents' cognitive skills during simulated surgical exercises are lacking.Thirty-seven surgical residents in both the precall and the postcall condition were tested for psychomotor and cognitive skill evaluation on a virtual-reality simulator with haptic feedback and hand-motion recording. To evaluate surgical skills, hand- and tool-movement smoothness, cognitive errors, and time to completion for specific tasks were analyzed.In addition increased cognitive errors, a significant decrease (P.01) was recorded in the proficiency variables of memory, attention, and intermodal coordination tasks when residents were in the postcall condition.Fatigue and sleep deprivation cause a significant deterioration in the surgical residents' cognitive skills as measured by virtual reality simulation. Psychomotor skills are also negatively impacted during tasks that require a combination of psychomotor and cognitive skills.

In an attempt to further standardize surgical training, the American Board of Surgery now requires that residents provide evidence that they are certified in flexible endoscopy. This prospective study was designed to determine whether, through a structured curriculum, junior level residents could learn to conduct competent and safe screening colonoscopy (SC). An Institutional Review Board-approved prospective analysis of SC performed by five postgraduate year-2 residents during the 2012-2013 academic year was completed. All SC were performed under direct supervision of one of the two surgical endoscopists after each resident passed a structured endoscopy simulation curriculum. The following metrics of the American Society for Gastrointestinal Endoscopy and the American College of Gastroenterology were recorded: bowel prep quality; cecal intubation; withdrawal time; number of visualized polyps; procedural duration; final pathology; adenoma detection rate (ADR); and, complications. Power analysis revealed that 108 procedures were required for an 80 per cent probability of data analysis accuracy. (American Society for Gastrointestinal Endoscopy ASGE/American College of Gastroenterology benchmark values in parentheses): 166 colonoscopies were performed, of which 149 met inclusion criteria. Bowel prep was considered "excellent" or "good" in 90 per cent of cases. The cecum was reached in 96 per cent of cases. Mean withdrawal time was 12 minutes (≥6 minute). Average procedure time was 30 minutes (≤ 30 minute). Polyp(s) were visualized and removed in 30 per cent of patients. The overall adenoma detection rate was 22.8 per cent (20%). The ADR for males was 29.5 per cent (25%). The ADR for females was 18.2 per cent (15%). Average polyp size was 7.7 mm (range: 2-25 mm). No patients were readmitted for bleeding or perforation. Within a structured learning environment, trained surgical endoscopists can teach junior level surgery residents to perform safe and competent screening colonoscopy.

The current standard for obtaining accurate sentinel lymph node (SLN) mapping is intraparenchymal lymphophilic dye/radiocolloid injection close to the breast tumor. We hypothesized that common lymphatic trunks drain both a large volume of breast parenchyma and skin and that intradermal or intraparenchymal routes flow to the same axillary node.99mTc-labeled filtered sulfur colloid was injected intradermally directly over the breast tumor in 119 patients. Blue dye was injected intraparenchymally in the same quadrant as the primary tumor (concordant quadrant) in 66 and in a discordant quadrant in 53 patients. During axillary exploration, both blue and gamma-emitting (hot) nodes were found. End points were SLNs that were hot and blue, either the same node or different nodes.In 62 (93.9%) of 66 of concordant quadrant and in 49 (92.5%) of 53 of discordant quadrant patients, the same SLN was both hot and blue (P = .99; Fisher's exact test). In eight cases in which two distinct nodes were blue and not hot and hot but not blue, the lymph nodes were very close to each other.The dermal and parenchymal lymphatics of the breast seemed to drain to the same axillary lymph nodes. Lymph from the entire breast seemed to drain through a small number of lymphatic trunks to one or two lymph nodes.

Modern hemodynamic therapy is not only the recognition and treatment of hypotension but also the avoidance and treatment of shock in its broadest sense. The major issues include the recognition of hypoperfusion of the body as a whole or its individual tissues and organ systems and the determination of the best endpoints for the treatment of shock. Even if all of the commonly used clinical indicators of shock are "normal," shock on a cellular, tissue, or organ basis may still be present. Whether "organ-specific" assessments, such as gastric tonometry or tissue oxygen tension measurement, are the ultimate answer to this problem remains to be seen. The determination of adequate intravascular volume (preload) continues to present major difficulties in the care of critically ill or injured patients. Although PCWP is frequently helpful, it is not a gold standard. A bedside ultrasonic technique, such as esophageal Doppler sonography, may replace the Swan-Ganz catheter technique in many patients.

Background and Objectives The number of positive axillary lymph nodes predicts prognosis and is often important in determining adjuvant chemotherapy in breast cancer patients. This study was undertaken to determine if differences in the extent of axillary node dissection would alter the number of reported positive nodes. Methods The study population consisted of 302 patients with invasive breast cancer who underwent complete (level I/II/III) axillary lymph node dissection. Assuming that all patients had undergone a level I/II dissection, it was determined how frequently a patient's nodal category (0, 1–3, 4–9, >10 positive nodes) would have been altered if a level I or level I/II/III dissection were performed. Results Assuming that all 302 patients had undergone a level I/II dissection, performing only level I dissection would have resulted in a change in nodal category in 15.9% of all patients and 36.1% of patients with positive nodes. The corresponding changes for a level I/II/III dissection would have been 4.3% and 9.5%, respectively. Conclusions Variations in the level of axillary node dissection for breast cancer can result in significant changes in the number of positive axillary nodes. This can potentially bias adjuvant chemotherapy recommendations if treatment decisions are based on this prognostic factor. J. Surg. Oncol. 2000;73:134–137. © 2000 Wiley-Liss, Inc.

A severe hypoxic insult is known to induce dramatic reductions in newborn intestinal blood flow and is, thus, considered a vector for the development of neonatal intestinal ischemic diseases. Dopexamine (DPX) is a novel synthetic agent that has potent B2-adrenoceptor and dopaminergic activity, the clinical effects of which include an increase in cardiac output and in mesenteric blood flow. Having previously shown that infusion of DPX before hypoxia (HYP) mitigated the reduction in newborn mesenteric blood flow, we sought to define its efficacy when given after an established hypoxic insult. Ultrasonic transit time blood flow probes were placed around the ascending aorta and cranial mesenteric artery of anesthetized, mechanically ventilated 0 to 2-day-old piglets. Small bowel mucosal oxygenation was observed with a tissue oxygen monitoring system. After stabilization, animals were subjected to one of the following: HYP (FIO2 = 0.12) for 60 minutes (n = 12); DPX (5 μg/kg/min) infusion begun 10 minutes after induction of HYP/DPX (n = 11). Almost no alterations in any of the monitored variables were shown in a group (n = 5) of similarly instrumented, untreated animals. In contrast, although both hypoxic piglet groups experienced significant (P < 0.05, analysis of variance) declines from baseline cardiac output, mesenteric blood flow, and mucosal oxygenation, each of these deleterious effects was significantly (P < 0.05) blunted in the DPX-treated animals. During periods of systemic hypoxemia, the reductions in neonatal mesenteric blood flow and oxygenation can be somewhat blunted by DPX. As such, this agent may prove of clinical benefit when an infant is threatened by a hypoxic episode.

Background/Purpose: Hypothermia (HT) remains a significant stress to the newborn and has been implicated in the pathogenesis of necrotizing enterocolitis (NEC). The authors assessed the effect of transient HT (32°C) on regional organ blood flow in anesthetized piglets at age 7 to 10 days preterm (PREM), 1 to 2 days (NB), and 1 to 2 weeks (NEO). Methods: Radiolabeled microspheres were used to determine organ blood flows (mL/min/g) at baseline, 15, and 60 minutes after HT and 60 minutes after rewarming to baseline core temperature. Results: Heart rate and cardiac output decreased significantly in all groups. Cardiac flow decreased significantly in the NEO group, and central nervous system (CNS) flow decreased significantly in the NB and NEO groups. Both returned to baseline levels after rewarming. The PREM group experienced decreased cardiac, CNS, and intestinal blood flows but not to significant levels. NB and NEO intestinal blood flow showed significant decreases, which remained so after rewarming (a response not seen in hypoxia or hypovolemia). Cardiac output did not return to baseline levels in any group. Conclusions: HT causes derangements in organ blood flows that differ from other deleterious stimuli such as hypoxia and hypovolemia. The prolonged intestinal ischemia supports HT as a factor in the development of NEC. This delay may offer opportunity to intervene in an attempt to lessen ischemiareperfusion injury.

Background. The purpose of this work was to determine the effects of hypoxemia on systemic hemodynamic variables and regional conduit arterial blood flows in neonatal piglets. Materials and methods. Using transit time blood flow probes, cardiac output and cranial mesenteric artery blood flow were monitored in groups of prematurely delivered (90% of term gestational age) and 2-week-old piglets prior to, during, and after exposure to a 30-min hypoxic ( F I O 2 = 0.12) challenge. Results. The documented alterations in systemic mean arterial pressure and cardiac output pressure during hypoxia and reoxygenation were consistent with the maturational age of the animals. In response to hypoxia, all animals demonstrated significant reductions in mesenteric blood flow, with returns to baseline levels during the 30-min reoxygenation phase. In still other prematurely delivered piglets, nutrient mesenteric arterial blood flows were measured using in vivo videomicroscopy. The marked hypoxemia-induced decline in mucosal blood flow was reversed by reoxygenation. Conclusions. The physiologic mechanisms responsible for neonatal mesenteric vasoactive responsiveness are present in conduit and in nutrient vessels well prior to birth and can be activated by a significant perturbation. These observations are germane insofar as they provide a stable, age-matched acute animal model to study neonatal intestinal ischemic diseases, including necrotizing enterocolitis.

Large surface-area burns in patients have been associated with a severe impairment in cardiac performance, as evidenced by a decline in cardiac output. The mechanisms responsible for this profound myocardial dysfunction are largely unknown. We investigated the effects of lymph isolated from the scalded hind limb of dogs on regional myocardial blood flow, coronary vascular reactivity, and contractile performance. Dogs were instrumented with ultrasonic dimension crystals in the myocardium supplied by the left anterior descending (LAD) and by the left circumflex (LCx) coronary arteries. After cannulating a hind limb lymphatic, lymph was infused directly into the LAD before and after a 10-second 100 degrees C hind limb scald. Scalding alone did not alter myocardial contractile performance in the LAD or LCx regions, coronary artery blood flow, or systemic hemodynamics. Interestingly, postburn lymph infused into the LAD resulted in a 38% decline in LAD zone segment shortening (p < 0.01 vs baseline) that lasted throughout the 5-hour observation period. In contrast, segment shortening in the (control) LCx region was unaffected by postburn lymph injections into the LAD. Regional myocardial blood flow (radiolabeled microspheres) in the LAD and LCx regions was unchanged after scald injury or intracoronary injection of postburn lymph. In addition, LAD coronary artery vascular reactivity to acetylcholine and nitroglycerin was also unaffected by the regional thermal injury or by injection of lymph into the LAD. These data suggest that a regional scald injury results in the production and release of a potent myocardial depressant factor(s) that produces a direct negative inotropic effect on the canine myocardium.

Background: Neonatal hearts have altered adhesion molecule interactions in response to ischemia-reperfusion. How this affects myocardial function is unknown. Methods: Isolated, buffer perfused 0- to 2-day (newborn) and 2-week piglet hearts were first subjected to 20-minute global, normothermic ischemia, followed by 45 minutes of reperfusion during which 150 × 106 newborn or 2-week neutrophils were infused. In some hearts, an antibody to SLex (CSLEX-1) was infused with neutrophils during reperfusion. Hemodynamic variables, including left ventricular developed pressure (LVDP), were recorded at timed intervals. Neutrophil CD-18, L-selectin, and SLex contents were measured by flow cytometry. Results: Full recovery of LVDP was observed in newborn hearts receiving newborn or 2-week-old neutrophils. Recovery of LVDP was depressed (p < 0.01, ANOVA) in 2-week-old hearts receiving 2-week old, not newborn, neutrophils. Infusion of CSLEX-1 in 2-week-old hearts restored LVDP to baseline. Whereas flow cytometry showed higher (p < 0.01, Student's t test) CD-18 and L-selectin expression on newborn versus 2-week-old neutrophils, newborn neutrophils expressed lower (p < 0.01) SLex levels. Conclusions: Initial “loose” neutrophil-endothelial selectin interactions are a necessary prelude to “firm” adhesion and reperfusion injury. Operations performed soon after birth may be better tolerated than when surgery is delayed; anti-SLex preparations may prove beneficial when performing cardiac procedures on older infants. (Surgery 1998;123:294-304)

Background: The effects of α-trinositol (1D -myo-inositol-1,2,6-triphosphate, IP3) on burn-induced edema formation were investigated. Methods: Lymph flow (QL; μl/min) and lymph-to-plasma protein ratio (CL/CP) were monitored in groups of five to six dogs before and 4 hours after (1) a 5-second 100° C or 90° C foot paw scald; (2) IP3 (45 mg/kg intravenous bolus, then a 20 mg/kg/hr infusion) 30 minutes before or after 100° C scald, or 30 minutes after 90° C scald. Hind paw venous pressure was elevated and maintained by outflow restriction until reaching steady state QL and (CL/CP)min. Macromolecular reflection coefficient (1 – CL/CP) was measured. Fluid filtration coefficient (Kf; ml/min/mm Hg/100 gm) was calculated. Relative paw weight gain (%) was measured. Results: Compared with preburn values, scald uniformly produced significant increases in QL, CL/CP, and Kf. IP3 significantly (p < 0.02, ANOVA) reduced paw weight gain when given before, but not after, 100° C burn (41% ± 5% versus 18% ± 7% preburn IP3 and 31% ± 3% postburn IP3). Compared with 90° C burn animals, postburn treatment significantly (p < 0.017) attenuated 4-hour increases in QL (550 ± 87 versus 252 ± 29 μl/min), Kf (0.016 ± 00 versus 0.007 ± 00 μl/min/mm/Hg/100gm), and relative paw weight gain (28% ± 3% versus 12% ± 5%). Conclusions: α-Trinositol given after a 90° C scald blunted edema formation at the site of scald, likely through reduced transmembrane fluid flux. (Surgery 1998;123:36-45.)

OBJECTIVE To determine the effects of burn lymph on pulmonary hemodynamic variables. METHODS A balloon-tipped catheter was fluoroscopically passed from a jugular vein into the right lower lobe (RLL) pulmonary artery of rats, its distal lumen used to measure pulmonary artery pressure. Inflation allowed measurement of RLL wedge pressure, which represents pulmonary venous pressure. After inflation, the RLL underwent constant flow pump-perfusion with carotid artery blood. Preburn (n = 5) or post-burn (n = 6) dog lymph was infused into the RLL for 50 minutes. MEASUREMENTS Because perfusion flow rate was constant throughout the experiment, RLL changes in pulmonary artery pressure reflect changes in pulmonary vascular resistance. RESULTS Animals given preburn lymph had no alterations in RLL pulmonary hemodynamics. The immediate, significant (p < 0.005, analysis of variance) increases in RLL pulmonary artery pressure (16.2 +/- 2.3 mm Hg at baseline vs. 35.4 +/- 2.1 mm Hg at 30 minutes) and pulmonary vascular resistance (0.0 at baseline vs 1.37 +/- 0.24 at 30 minutes) after burn lymph injection persisted beyond infusion interruption. CONCLUSION The persistent pulmonary hypertensive response to postburn lymph warrants further investigation.

The following experiments were conducted to determine whether, and the mechanisms through which, endogenous peptides alter coronary artery blood flow. Ultrasonic transit time probes were placed around the ascending aorta and left anterior descending coronary artery in groups of anesthetized, open-chest dogs. A Millar pressure catheter monitored left ventricular developed pressure. Intracoronary artery bolus injections of adenosine (a purinergic receptor activator), pinacidil (a KATP channel activator), calcitonin gene-related peptide (CGRP; which causes vascular smooth muscle relaxation by intracellular increases in cyclic-AMP), and adrenomedullin (mechanism unknown) each significantly (P0.05, Student's t test) increased coronary blood flow in a dose-dependent fashion, without altering systemic hemodynamic measurements. Intracoronary artery injection of U37883A (a KATP channel antagonist) significantly (P0.05) blocked the coronary vasodilator responses to adenosine, adrenomedullin, and pinacidil. Intracoronary xanthine amine congener (an adenosine receptor antagonist) blocked only the responses to adenosine and adrenomedullin, not pinacidil. Intracoronary CGRP8-37 (CGRP receptor antagonist) blocked only the vasodilator response to CGRP. These data suggest that the coronary vasodilator effect of adrenomedullin is initiated first by activation of adenosine receptors, and subsequently through KATP channels-not by activation of CGRP receptors. That there were no changes in left ventricular developed pressure or in systemic hemodynamics after intracoronary artery infusions of adrenomedullin indicates that this endogenous peptide may have clinical utility in facilitating myocardial protection or preconditioning.

For further characterization of neonatal mesenteric α1-adrenoceptor populations, an extracorporeal perfusion circuit was established to control intestinal blood flow in 0-2 day old piglets. Activation of α1-adrenoceptors was first documented by observing dose-dependent increases in mesenteric perfusion pressure after intra-mesenteric arterial injection of methoxamine and noradrenaline. Peripheral intravenous injections of WB 4101 (a competitive α1A-adrenoceptor antagonist), but not clorethylclonidine (CEC, an α1B-adrenoceptor antagonist), significantly (P < 0.05, analysis of variance) blunted mesenteric vasoconstrictor responses to those agonists. That the mesenteric vasoconstrictor response to mesenteric plexus stimulation was unaltered by CEC, but was muted by both WB 4101 and SK&F 104856 (a post-junctional α1- and α2-adrenoceptor antagonist) suggests that pre- and post-junctional α1A-adrenoceptors are present and functional at birth.

To characterize the mesenteric alpha1- and alpha2-adrenoceptor populations in newborn piglets, an extracorporeal circuit was established to control intestinal blood flow in 0- to 2-day old and 10- to 14-day old animals. In both groups, alpha-adrenoceptor activation was first documented by observing dose-dependent increases in mesenteric perfusion pressure after intramesenteric arterial injection of alpha-adrenoceptor agonists. In the 10- to 14-day old piglets, mesenteric vasoconstrictor responses to alpha1-adrenoceptor agonists (methoxamine and norepinephrine) and an alpha2-adrenoceptor agonist (BHT-933) were each blunted (P0.05, analysis of variance) by peripheral intravenous injections of prazosin (an alpha1-adrenoceptor antagonist) and yohimbine (an alpha2-adrenoceptor antagonist), respectively. The mesenteric vasoconstrictor responses to those agonists were not significantly attenuated by prazosin or yohimbine in 0- to 2-day old animals, nor were they blunted by YM-12617 (alpha1-adrenoceptor antagonist) or idazoxan (alpha2-adrenoceptor antagonist)--compounds that are structurally unrelated to prazosin and yohimbine, respectively. In addition, mesenteric vasoconstrictor responses to other known vasoconstrictor agents--angiotensin II, neuropeptide Y, and a thromboxane A2 mimic (U-46619)--were not effected in either age group by prazosin or yohimbine, implying these agents act independently of alpha-adrenoceptor mechanisms. These data suggest that (1) there exists functional mesenteric alpha1- and alpha2-adrenoceptor-like activity in 10- to 14-day old piglets that, in 0- to 2-day old animals, is not specifically expressed; and (2) mesenteric alpha-adrenoceptor function becomes more selective as newborn piglets mature.

Background. This study was undertaken to compare the efficacy of a novel synthetic material (TMS-1) with polytetrafluoroethylene, polypropylene, and primary closure of experimentally fashioned clean and contaminated abdominal wounds. Methods. One square centimeter full-thickness abdominal wall defects were created in each of the four abdominal quadrants of anesthetized rats (n=6). Patches of polytetrafluoroethylene, polypropylene, and a polyurethane-polypropylene composite material (TMS-1) were used to repair three of these defects; the fourth was primarily closed. A second group of rats (n=9) underwent the same operative protocol; however, peritonitis was induced at the time of operation by using the fecal inoculation technique. Animals were killed 2 to 3 weeks later, and surface area and severity of formed adhesions were assessed. Results. By all methods of assessment, primary closure proved significantly superior to all other methods of closure in clean and contaminated conditions. The three synthetic materials were equally matched for surface area involved in adhesion formation. When compared with the other synthetic materials, TMS-1 was associated with significantly milder adhesions in uninfected (p Conclusions. The clear superiority of TMS-1 over other nonabsorbable synthetic materials shown in this pilot study warrants further investigation relative to its use to close large abdominal wall defects.

To determine the effects of anti-inflammatory agents on hydrochloric acid lung injury, the heart and lungs were harvested from rats, placed in a lung chamber, constant flow perfused with whole blood, and ventilated. The following experiments were conducted: observation alone; intratracheal injection of normal saline; intratracheal hydrochloric acid; and intravenous meclofenamate or indomethacin before intratracheal hydrochloric acid. Wet-to-dry lung weights were measured. Peak airway pressures increased immediately (p < .001 vs. baseline; ANOVA) in all intratracheal groups, hydrochloric acid producing even greater (p < .05) increases than saline-effects unaltered by meclofenamate or indomethacin. The increased (p < .001 vs. baseline) 2-h pulmonary artery pressures in hydrochloric acid-treated groups were unaltered by meclofenamate or indomethacin. All hydrochloric acid-treated groups demonstrated increases (p < .05) in weight that were unchanged by meclofenamate or indomethacin. These data suggest that the beneficial effects of these medications described elsewhere, using a variety of in vivo lung injury experimental models, may be attributed to their experimental design, or to contributions from organs/systems outside the pulmonary circuit.

Acute hemorrhage in premature infants occurs as the result of obstetrical complications, birth trauma, or operative procedures. This study evaluates the response of the preterm piglet to acute hemorrhage and resuscitation. Piglets delivered by Caesarean section 7-14 days preterm underwent acute arterial/venous hemorrhage (20 cc/kg). At 0, 15, and 60 rain after hemorrhage, hemodynamic parameters and regional blood flows (reference organ technique) were measured. Animals were then resuscitated with shed blood (20 cc/kg), crystalloid (60 cc/kg), or colloid (dextran 40, 20 cc/kg) with study parameters obtained 30 min later (statistical analysis by ANOVA). Significant decreases in blood pressure (BP) and cardiac output (CO) occurred after hemorrhage. BP and CO were reestablished to near control levels following resuscitation with blood and crystalloid. Dextran failed to return BP to baseline; however, it resulted in CO 1.7 × control. Heart and CNS blood flow were not significantly influenced by hemorrhage; however, dextran increased flows to these organs significantly above control levels. In the kidney and small bowel, flows decreased significantly following hemorrhage; blood and crystalloid restored flows to near baseline, while dextran resulted in flows significantly greater. In summary, the preterm piglet responds to hemorrhage with maintenance of blood flow to the heart and brain and significantly decreased flows to the kidney and small intestine. Flows following resuscitation with blood and crystalloid are comparable to those in control. Dextran resuscitation resulted in flows significantly greater than baseline; this response might be detrimental with ongoing hemorrhage and/or prolonged ischemia.

Objective : To determine which serotoninergic receptor subtype(s) mediates the regional vasodilator response to scald injury. Design : Prospective, randomized trial. Setting : Microcirculation research laboratory. Subjects : Anesthetized dogs. Interventions : Mechanically ventilated dogs underwent cannulation of a brachial artery and placement of an ultrasonic flow probe around one femoral artery. All animals received a 2% to 3% body surface area partial thickness scald injury by immersing the paw ipsilateral to the instrumented femoral artery into 100°C water for 5 secs. In one group of dogs, BMY 7378 (a serotoninergic 1A receptor antagonist) was given by the peripheral intravenous route before burn. These results were compared with those findings obtained from a group of animals that received a burn only, and groups of animals given a peripheral intravenous injection of methysergide (a serotoninergic receptor antagonist) or ritanserin (a serotoninergic 2 receptor blocking agent) before burn. Experiments were conducted for two postburn hours. Measurements and Main Results : Burn injury caused a marked and persistent increase in regional (e.g., femoral artery) blood flow, an effect that was significantly blunted by preburn administration of the serotoninergic receptor antagonist, methysergide. Preburn administration of BMY 7378 increased baseline femoral blood flow by 13%, reflecting its known serotonin agonist properties. However, when compared with the mean postscald increases in femoral blood flow over baseline seen in scald only dogs and in animals given the serotoninergic 2 receptor blocking agent, ritanserin (before scald), the BMY 7378-treated group demonstrated a significant (p < .001 by analysis of variance) 2-hr-postscald blunting of this femoral vasodilator response. Conclusion : These data suggest that serotoninergic 1A -like receptors play an integral, albeit not an exclusive, role in blood flow regulation to the site of burn injury. (Crit Care Med 1995 ; 23 :1112-1116)

OBJECTIVE: The authors determined the effects of dopamine and dobutamine on organ blood flow in newborn piglets. SUMMARY BACKGROUND DATA: Although the hemodynamic effects of dopamine and dobutamine are well described in adults, little is known of their consequences in neonates, and their impact on organ perfusion in premature infants is unclear. METHODS: Cannulae were placed in the femoral vessels and left atrium of term (1-14 days old) and prematurely delivered (Ceasarean section at 90% of term gestation) piglets. After stabilization, radiolabeled microspheres were injected. A continuous infusion of dopamine or dobutamine was started, and other microspheres were injected at 5, 10, and 15-micrograms/kg/minute drug doses (allowing a 20-minute equilibration period at and between each dose). Blood flows (mL/minute/g tissue) to organs were determined using reference organ techniques. RESULTS: In term animals only, dobutamine and dopamine increased systemic mean arterial pressure at the 15-micrograms dose. In term piglets, dobutamine produced dose-dependent increases (p < 0.05, analysis of variance) in heart and brain blood flow, although small intestinal blood flow decreased (1.47 +/- 0.13 mL/minute/g baseline to 1.31 +/- 0.11 mL/minute/g at 15-micrograms dose). There were no significant changes in blood flow to these organs in preterm animals. Dopamine significantly (p < 0.05) increased heart blood flow in both groups. Dopamine also increased small intestinal blood flow in term (1.63 +/- 0.22 mL/minute/g baseline to 3.13 +/- 0.34 mL/minute/g at 15-micrograms dose) and premature (0.31 +/- 0.10 mL/minute/g baseline to 1.11 +/- 0.29 at 15 micrograms dose) piglets. CONCLUSIONS: Dopamine may prove a valuable adjunct when a premature infant is at risk for conditions that reduce alimentary tract blood flow.

One hundred seventy-one laparoscopic cholecystectomies were done by senior surgery residents who received only traditional "hands-on" training. Eight patients (5%) required conversion to open cholecystectomy, and two had complications requiring immediate celiotomy (one common bile duct injury, one "dropped" gallbladder). The average operative time was 91 minutes (range, 30 to 245 minutes). There were no deaths and only five postoperative complications related to the procedure (retained common bile duct stone in four cases, intra-abdominal hemorrhage in one). There were three complications unrelated to the procedure. Data acquired from recent resident training program graduates show that these practicing surgeons are doing laparoscopic cholecystectomy with a 95% success rate and have yet to encounter appreciable complications. We concluded that a large-volume general surgery resident training program provides adequate opportunity for training surgeons in the techniques of laparoscopic cholecystectomy; there is no need to attend an expensive and time-consuming classroom and animal laboratory course.

Newborn piglets (aged 1 to 2 days and 7 to 14 days) were used to study (1) the redistribution of organ blood flow after a 25% acute blood loss and (2) the response to resuscitation with shed blood (20 mL/kg), crystalloid (normal saline [NS] or lactated Ringer's [LR]; 60 mL/kg), and colloid (dextran-40, 20 mL/kg). Hemodynamic parameters showed little differences in the response to hemorrhage and resuscitation. The two age groups had no significant differences in parameters or blood flow (results combined). The animals maintained flow to the heart and central nervous system (CNS) and had significantly decreased flow to the kidneys and splanchnic organs. In the gastrointestinal tract, the small intestine was affected most severely, with a significant decrease in blood flow, especially to the mucosa. In all organ systems, Dextran 40 restored blood flow to levels significantly above the baseline. Shed blood and crystalloid restored flow to organs sustaining decreased flow, but crystalloid did not restore flow to the baseline level in the kidney and all segments of the gastrointestinal tract.

In a canine hind leg model, lymph flow (QL), lymph (CL), and plasma (CP) total protein concentrations, the reflection coefficient for total proteins (sigma d), and the filtration coefficient (Kf) were determined before and for 6 hours after a 5-second 100 degrees C hind paw scald (3% total body surface area, TBSA). Before injury, hind leg venous pressure was elevated and maintained by outflow restriction until a minimal, steady-state CL/CP ratio was achieved. Albumin (5%) was infused 30 minutes after the scald at low (0.4 mL/kg/% TBSA) or high (2 mL/kg/% TBSA) doses. Scald uniformly increased QL, CL/CP, Kf, and paw weight gain (PWG). Whereas postburn infusion of low-dose albumin mildly attenuated increases in CL/CP and PWG noted in scald-alone animals, no differences were noted between the scald and scald/high-dose albumin groups.

Ultrasonic probes were placed around dog femoral arteries to record blood flow. Hind paw scalding with boiling water (5 s) caused a marked increase in ipsilateral femoral blood flow that persisted for the 2-h observation period. Contralateral femoral blood flow and systemic and pulmonary vascular resistances were unchanged. Compared to scald only animals, methysergide pretreatment diminished and shortened the femoral vasodilator response to scald (109 +/- 14 vs 243 +/- 27 ml/min at 5 min; 59 +/- 14 vs 191 +/- 31 ml/min at 2 h). Pretreatment with ritanserin, BW A1433U83, atropine, ICI 118551, diphenhydramine, ranitidine, meclofenamate, L-nitro-arginine methyl ester, 3-amino-1,2,4-triazine, and U 37883A had no effect on the increased femoral blood flow response to scald, suggesting this vasodilator response is not dependent upon activation of serotonergic2, adenosineA1, muscarinic, beta 2-adrenergic, histaminergic1 or histaminergic2 receptors, on cyclooxygenase products, endothelium-derived relaxing factor derived from nitric oxide (NO) synthase III, NO derived from NO synthase II, or KATP channels, respectively. Methysergide given after burn immediately reduced the augmented femoral blood flow to preburn levels, suggesting the vasodilator response to scald is mediated through continual activation of local serotonergic1-like receptors, which may be target site(s) for therapeutic interventions to influence burn-induced hemodynamic alterations.

We sought to define the extent to which a motion analysis-based assessment system constructed with simple equipment could measure technical skill objectively and quantitatively.An "off-the-shelf" digital video system was used to capture the hand and instrument movement of surgical trainees (beginner level = PGY-1, intermediate level = PGY-3, and advanced level = PGY-5/fellows) while they performed a peg transfer exercise. The video data were passed through a custom computer vision algorithm that analyzed incoming pixels to measure movement smoothness objectively.The beginner-level group had the poorest performance, whereas those in the advanced group generated the highest scores. Intermediate-level trainees scored significantly (p0.04) better than beginner trainees. Advanced-level trainees scored significantly better than intermediate-level trainees and beginner-level trainees (p0.04 and p0.03, respectively).A computer vision-based analysis of surgical movements provides an objective basis for technical expertise-level analysis with construct validity. The technology to capture the data is simple, low cost, and readily available, and it obviates the need for expert human assessment in this setting.

Background Health care continues to expand in scope and in complexity. In this changing environment, residents are challenged with understanding its intricacies and the impact it will have on their professional activities and careers. Aim Embedding each of the competency elements in residents in a meaningful way remains a challenge for many surgery residency program directors. Methods We established a nonclinical rotation to provide surgery postgraduate year-1 (PGY-1) residents with a structured, multifaceted, largely self-directed curriculum into which each of the 6 core competencies are woven. Posttesting strategies were established for most curricular experiences to ensure to the greatest possible extent that each resident will have achieved an acceptable level of understanding of each of the competency areas before being given credit for the rotation. Results By uniformly exceeding satisfactory scores on respective objective analyses, residents demonstrated an increased (at least short-term) understanding of each of the assessed competency areas. Conclusion Our project sought to address a prior lack of opportunity for our residents to develop a sound foundation for our residents in systems-based practice. Our new rotation addresses systems-based practice in several different learning environments, including emergency medical service ride-along, sentinel event participation, and hospice visits. Several research projects have enhanced the overall learning program. Our experience shows that a rotation dedicated to competency training can provide an innovative and engaging means of teaching residents the value of each element.

Advances in medical field have introduced new and progressive ways to intensify surgical resident training and surgical skills learning by developing systematic simulator training programs alongside traditional training. Both training methods need constant presence of a competent surgeon to subjectively assess the surgical dexterity of the trainee. Several studies have been done to measure user’s skill objectively and quantitatively, but all use sensors which could interfere with skill execution. Also the sterilization process in an actual surgery makes the use of sensors impossible. This paper proposes a novel video-based approach for observing surgeon’s hand and surgical tool movements in both surgical operation and training. Data is captured by video camera and then explored using computer vision algorithm. Finally by analyzing basic statistical parameters, observer-independent model has been developed through objective and quantitative measurement of surgical skills.

Over the past 14 years, 146 patients with penetrating colon trauma were managed by primary repair with/without resection (PR, n = 55), and by diverting colostomy (DC, n = 91). These groups did not differ in terms of age, ISS (Injury Severity Scale), PATI (Penetrating Abdominal Trauma Index), a-AIS (abdominal Abbreviated Injury Scale), or preoperative hypotension. No intergroup differences were manifested in intra-abdominal complications (fistula/leak, abscess, pancreatitis, intestinal obstruction, wound dehiscence). The percentage of patients who experienced at least one major intra-abdominal complication did not differ statistically when the two groups were compared--12.7% in PR versus 11% in DC--although risk in both groups increased with the additional number of organs injured. Wound infection was significantly higher (p0.05) in the PR group (19.6%) compared with the DC group (9.4%). Mortality in the PR and DC groups was 0% and 3.6%, respectively. One hundred and ten patients who underwent elective colostomy closure following trauma had a 9.1% intra-abdominal complication rate and a 3.6% wound infection rate. These risks should be considered when colostomy is selected to manage patients with penetrating colon injury. These data support primary repair of all colon injuries, reserving skin closure for patients with limited collateral damage.

Background Although surgeons perform procedures and tasks under a significant amount of cognitive load, current simulators focus on training psychomotor skills in isolation. This may limit the transfer of learned skills to actual surgical environments. Methods Visuohaptic simulations were created that required participants to hone psychomotor skills in the presence of cognitive load. A control group (n = 7) trained on conventional skills simulator and their performance was compared with the experimental group (n = 7) in terms of learning curves and performance on a transfer task. Results The experimental group performed significantly better than the control group in terms of both learning curves and performance on the transfer task. Conclusions Simulations that combine psychomotor and cognitive skills training are more effective than simulators that focus on psychomotor skills in isolation.

BACKGROUND: Night floats have evolved in the era of limited resident work hours. This study was designed to define the effect of restricted nighttime duty hours on the psychomotor and cognitive skills of surgery residents. METHODS: To quantify the effect of fatigue on the skills of residents on day-shift and night-float rotations, residents were asked to complete visuohaptic simulations before and after 12-hour duty periods and to rate their fatigue level with questionnaires. RESULTS: Both groups showed significant decrements in proficiency measures after their shifts compared with baseline. The night-float group showed more significant declines (P < .05) in all areas assessed than the day-shift group. The night-float group was significantly less proficient in cognitive tasks after their shifts compared with the day-shift group. CONCLUSIONS: The deterioration of surgical proficiency is to a degree dependent on the time of day during which call occurs, not solely on the length of call.

Administration of hyperosmolar fluids to burn patients has been proposed as a means of decreasing resuscitative fluid volume and, subsequently, wound edema accumulation. To test this hypothesis, canine hindpaw lymph flow (QL) and lymph (CL) and plasma (CP) total protein concentrations were measured, and capillary filtration coefficient (Kf) was calculated before and for 6 h after a 5-s 100 degrees C footpaw scald. Scald was followed 30 min later by bolus infusion (4 ml/kg) of 7% saline or 6% Dextran 70 or the two in combination. Before scald, venous pressure was elevated until a minimal CL/CP was reached. The reflection coefficient (sigma d) was calculated by the formula: 1-minimal CL/CP. Scald increased QL, CL/CP, and Kf, but sigma d was decreased (P less than 0.05). Compared with burn alone, 7% saline exacerbated burn-induced increases in QL and Kf. In contrast, infusion of Dextran 70 did not exacerbate these changes in QL or Kf. Perhaps more importantly, Dextran 70 may have attenuated the increase in CL/CP and reduced edema formation in the burned hindpaw. However, the addition of 7% saline to the dextran eliminated these beneficial effects.

Hyaluronan (formerly hyaluronic acid) is an important constituent of the interstitial matrix in skin. Following major burn injury in animal models, plasma hyaluronan can increase to levels 10-fold greater than normal. The present experiments were designed to determine whether this is a result of the increased lymph flow (QL) accompanying the injury or of an increased release of hyaluronan from the burned skin and subcutaneous tissue. The lateral saphenous vein and a prenodal lymphatic were cannulated in the hindpaw of five anesthetized canines. Hindpaw venous pressure was elevated until the total protein concentration in lymph declined to steady-state levels, and QL and hyaluronan flux (QL X [hyaluronan]) was measured. A minor burn was inflicted by immersion of the paw into 100 degrees C water for five sec, and measurements were repeated at regular intervals for a minimum of 4 hr. Burn injury resulted in significant and persistent increases in QL (154 +/- 61 microliters/min versus 562 +/- 105 microliters/min 4 hr postburn) and lymph total protein concentration (1.34 +/- 0.04 g/dl versus 4.08 +/- 0.18 g/dl 4 hr postburn), while lymph hyaluronan concentration fell (3.01 +/- 0.20 micrograms/ml versus 2.1 +/- 0.16 micrograms/ml 4 hr postburn). The resultant increase in hyaluronan flux (0.42 +/- 0.13 microgram/min versus 1.17 +/- 0.22 microgram/min 4 hr postburn) appears to be a function of lymph flow rather than burn-induced release of skin hyaluronan. Hence, the increased plasma concentration of hyaluronan following major burns is likely a consequence of increased lymph flow from the site of injury.

Thermal injury results in pronounced physiologic alterations in microcirculation at the site of tissue damage. The consequence of these changes is an increase in microvascular permeability, leading to the accumulation of tissue edema, or subeschar tissue fluid (STF). One of the adverse properties of edema is its capacity in vitro to inhibit cell-mediated immune function. Since previous studies evaluated STF collected 5 to 7 days after thermal injury, the present study was designed to determine the time frame during which STF demonstrates its immune suppressive nature. Seven patients with severe thermal injury (30% to 100% total body surface area) were entered into the study. STF was collected in serial fashion, beginning as early as 9 hours after injury and continuing until fascial excision or patient death (maximum of 139 hours after injury). The addition of STF to cultures of lymphocytes obtained from healthy donors resulted in complete inhibition of mitogen-induced lymphocyte proliferation (MILP). Serum collected concomitantly from this group of patients was also capable of inhibiting MILP. From its inception, STF possesses the ability to inhibit MILP; this suppressive nature is stable, persisting for prolonged periods of time. The gradual absorption of STF likely contributes to the serologic evidence of cell-mediated immune suppression documented in victims of severe thermal injury.

Surgery training requires residents to focus on tasks while minimizing the effect of distractions. There is a need to develop training methodologies that can enable surgical residents to hone this ability.Fourteen surgical residents were divided into 2 groups. They were trained to perform simulated tasks in a noiseless environment and subsequently performed these tasks in a distractive one. In a follow-up experiment, an experimental group was trained in noisy and distractive conditions and was compared with a control group trained in noiseless conditions.Residents who trained in noiseless environments possessed decreased surgical proficiency when performing the identical tasks in realistic environments (P.05). Pretraining in a noisy environment improves surgical proficiency.Noise and distractions can significantly impede performance of surgical residents, but this effect can be nullified by introduction of noise and distractions in the training environment.

Surgical residents are exposed to a significant amount of cognitive load during call. While various efforts have been made to quantify the effect of fatigue and sleep deprivation on the psychomotor skills of surgical residents, there is very little investigations into the effect of these factors on cognitive skills. However, this is an important issue in medical curriculum design, as much of the medical errors are procedural in nature and are not psychomotor. In this paper, we present a study that aimed to quantify the effect of fatigue on cognitive skills. We employed hand movement data for developing a proficiency measure of surgical skill. The difference in proficiencies measured through hand movement post call and pre call was determined. The simulation tasks were designed to challenge working memory, attention of the user. The results showed a significant difference in hand movement proficiencies as well as behavioral errors pre and post-call. EEG Data was also gathered during simulation tasks pre and post call through the B-Alert® Bluetooth EEG technology. The B-Alert® software was analyzed to reveal ratings of alertness/drowsiness, engagement, mental workload and distraction. The results showed statistically significant difference in EEG ratings in pre call and post call condition.