A Modified Burn Comb Model With a New Dorsal Frame That Allows for Local Treatment in Partial-Thickness Burns in Rats.

Burn wound progression (BWP) leads to vertical and horizontal injury extension. The "burn comb model" is commonly used, in which a full-thickness burn with intercalated unburned interspaces is induced. We aimed to establish an injury progressing to the intermediate dermis, allowing repeated wound evaluation. Furthermore, we present a new dorsal frame that enables topical drug application. Eight burn fields and six interspaces were induced on each of 17 rats' dorsa with a 10-second burn comb application. A developed 8-panel aluminum frame was sutured onto 12 animals and combined with an Elizabethan collar. Over 14 days, macroscopic and histologic wound assessment and laser speckle contrast imaging (LSCI) were performed besides evaluation of frame durability. The 10-second group was compared with nine animals injured with a full-thickness 60-second model. Frame durability was sufficient up to day 4 with 8 of the 12 frames (67%) still mounted. The 60-second burn led to an increased extent of interspace necrosis (P = .002). The extent of necrosis increased between days 1 and 2 (P = .001), following the 10-second burn (24% ± SEM 8% to 40% ± SEM 6%) and the 60-second burn (57% ± SEM 6% to 76% ± SEM 4%). Interspace LSCI perfusion was higher than burn field perfusion. It earlier reached baseline levels in the 10-second group (on day 1: 142% ± SEM 9% vs 60% ± SEM 5%; P < .001). Within day 1, the 10-second burn showed histological progression to the intermediate dermis, both in interspaces and burn fields. This burn comb model with its newly developed fixed dorsal frame allows investigation of topical agents to treat BWP in partial-thickness burns.

Preoperative predictability of right ventricular failure following surgery for Ebstein's anomaly.

OBJECTIVES: Postoperative right ventricular (RV) failure is a severe complication after tricuspid valve (TV) surgery in patients with Ebstein's anomaly. We investigated the preoperative predictability of postoperative mortality and morbidity by assessing the influence of age, RV size and RV function on in-hospital mortality and on the clinical course during the intensive care unit (ICU) stay. METHODS: We retrospectively analysed 189 patients who had undergone TV surgery for Ebstein's anomaly at our centre. For this study, only patients with preoperative cardiac magnetic resonance imaging (MRI) scans, who were operated on from 2005 to May 2018, were included. Three potential risk factors were proposed: (i) RV end-diastolic volume index >200 ml/m2, (ii) RV ejection fraction (EF) <40% and (iii) age at operation >50 years. Primary end points were death or the need for extracorporeal membrane oxygenation. Secondary end points were postoperative inotropic therapy, ventilation time, renal failure and duration of ICU stay and hospital stay. RESULTS: A total of 70 patients with preoperative cardiac MRI scans were included: 57 had undergone TV repair and 13 TV replacement. Thirty patients exhibited none of the defined risk factors, 24 patients exhibited 1 risk factor, 13 patients exhibited 2 risk factors and 3 patients exhibited 3 risk factors. There were 4 in-hospital deaths (6%): 3 of these patients had 3 risk factors, and 1 patient had 2 risk factors. In patients with 1 or more risk factors, the odds ratio for primary end point was 2.5 (P = 0.43) and in patients with 2 or more risk factors, the odds ratio was 18.5 (P = 0.001). Patients with at least 1 risk factor required prolonged inotropic drug administration and required a longer hospital stay (median 20 days vs 14 days, P = 0.029). Patients with at least 2 risk factors showed a significantly prolonged ventilation time (median 10 h vs 6 h, P = 0.001). Time in the ICU was longer in patients with 2 or more risk factors (median 9 days vs 4.5 days, P = 0.003). CONCLUSIONS: RV end-diastolic volume index >200 ml/m2, RV-EF <40% and age >50 years are helpful factors to identify patients with an increased perioperative risk. The results also suggest that earlier surgery may yield more favourable results in patients with Ebstein's anomaly.

Microsurgeons do better--tactile training might prevent the age-dependent decline of the sensibility of the hand.

Recent data demonstrate that the normal sensibility of the hand seems to be age-dependent with the best values in the third decade and a consecutive deterioration afterwards. However, it is not clear if long-term tactile training might prevent this age-dependent decline. We evaluated sensibility of the hand in 125 surgeons aged between 26 and 75 years who perform microsurgical operations, thereby undergoing regular tactile training. We examined sensibility of the radial digital nerve of the index finger (N3) and the ulnar digital nerve of the small finger (N10) using static and moving two-point discrimination (2PD) tests and compared the results to 154 age-matched individuals without specific long-term tactile training. We found significantly lower static and moving 2PD values for the sixth, seventh, and eighth decade of life in the microsurgery group compared to the control group (p < 0.05). This study demonstrates that long-term tactile training might prevent the known age-dependent decline of the sensibility of the hand.