Effect of intra-abdominal pressure on respiratory function in patients undergoing ventral hernia repair

AIM: To determine the influence of intra-abdominal pressure(IAP) on respiratory function after surgical repair of ventral hernia and to compare two different methods of IAP measurement during the perioperative period. METHODS: Thirty adult patients after elective repair of ventral hernia were enrolled into this prospective study.IAP monitoring was performed via both a balloontipped nasogastric probe [intragastric pressure(IGP), Ci MON, Pulsion Medical Systems, Munich, Germany] and a urinary catheter [intrabladder pressure(IBP), Uno Meter Abdo-Pressure Kit, Uno Medical, Denmark] on five consecutive stages:(1) after tracheal intubation(AI);(2) after ventral hernia repair;(3) at the end of surgery;(4) during spontaneous breathing trial through the endotracheal tube; and(5) at 1 h after tracheal extubation. The patients were in the complete supine position during all study stages.RESULTS: The IAP(measured via both techniques) increased on average by 12% during surgery compared to AI(P < 0.02) and by 43% during spontaneous breathing through the endotracheal tube(P < 0.01). In parallel, the gradient between РаСО2 and Et CO2 [Р(а-et)CO2] rose significantly, reaching a maximum during the spontaneous breathing trial. The PаO2/Fi O2 decreased by 30% one hour after tracheal extubation(P = 0.02). The dynamic compliance of respiratory system reduced intraoperatively by 15%-20%(P < 0.025). At all stages, we observed a significant correlation between IGP and IBP(r = 0.65-0.81, P < 0.01) with a mean bias varying from-0.19 mm Hg(2SD 7.25 mm Hg) to-1.06 mm Hg(2SD 8.04 mm Hg) depending on the study stage. Taking all paired measurements together(n = 133), the median IGP was 8.0(5.5-11.0) mm Hg and the median IBP was 8.8(5.8-13.1) mm Hg. The overall r2 value( n = 30) was 0.76(P < 0.0001). Bland and Altman analysis showed an overall bias for the mean values per patient of 0.6 mm Hg(2SD 4.2 mm Hg) with percentage error of 45.6%. Looking at changes in IAP between the different study stages, we found an excellent concordance coefficient of 94.9% comparing IBP and IGP( n = 117).CONCLUSION: During ventral hernia repair, the IAP rise is accompanied by changes in Р(а-et)CO2 and PаO2/Fi O2-ratio. Estimation of IAP via IGP or IBP demonstrated excellent concordance.

Short-term effects of vacuum massage on epidermal and dermal thickness and density in burn scars: an experimental study

Background:Vacuum massage is a non-invasive mechanical massage technique invented to treat burns and scars.To date,no effects of vacuum massage on thickness and density of human scar tissue have been reported.The process in which external stimuli are converted into biochemical responses in the cell is known as mechanotransduction.In the skin endothelial cells,fibroblasts and myofibroblasts embedded in the extracellular matrix(ECM)sense mechanical stimuli(created by vacuum massage)and may promote intracellular processes leading to matrix remodelling.Since mechanotransduction could be a plausible working mechanism for vacuum massage as an anti-scarring therapy,this study aims to investigate the short-term effects of vacuum massage on thickness and density of epidermis and dermis in burn scars in order to find proof of ECM remodelling.Methods:A one group experimental study was performed.Patients with burn scars on upper extremities,lower extremities,and trunk were recruited for participation in this study.The DUB?cutis 22 MHz ultrasound scanner was used to assess thickness and density of the epidermal and dermal skin layers.After baseline measurements,vacuum massage was performed according to a pre-defined protocol.Measurements were carried out at 5 min,30 min,1 h,and 2 h post-intervention.Results:Thirteen scar sites from 9 different patients were investigated.In 8 out of the 13 scar sites,a disruption of the epidermis was noticed after the vacuum massage.Five minutes after the intervention,epidermal density decreased statistically significantly(p=.022)and dermal thickness increased(p=.018).Both changes lasted for more than 1 h,but after 2 h,the changes were no longer statistically significant.Dermal density decreased significantly(p=.048)immediately after the intervention,and this decrease was still present after 2 h(p=.011).Conclusions:Preliminary results show that the disruption of the epidermis may indicate that vacuum massage could be able to actually breach the skin barrier.The statistically significant changes in the dermal layers could suggest an increased ECM production after vacuum massage.