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Introduction: Hypertrophic scarring is a common and debilitating consequence of burn scars. While there is limited evidence for current treatment options, laser therapy has been shown to be effective, low risk and minimally invasive. This study assesses the use of carbon dioxide lasers and intense pulsed light devices in the treatment of hypertrophic burn scars. Methods: In this case series, patients were recruited from a hypertrophic burn scar waitlist and completed a Patient and Observer Scar Assessment Scale prior to and six weeks after laser therapy. The Nordlys (intense pulsed light) and CO2RE (carbon dioxide) systems from Candela Medical were used, with a range of settings used depending on the assessment of the burn scar. The differences between scores were calculated for the total Patient and Observer Scar Assessment Scale score, pain, itch, colour, stiffness, thickness, irregularity and the overall opinion of the scar. Statistical analysis was completed using a paired, two-tailed student T test. Results: A total of 31 patients were recruited for this trial with a range of scar locations, surface areas and mechanism of burn injury. The calculated difference in mean showed a significant reduction for the overall Patient and Observer Scar Assessment Scale score (1.93, p < 0.0001), pain (1.39, p = 0.0002), itch (1.84, p = 0.0002), colour (1.97, p < 0.0001), stiffness (2.47, p < 0.0001), thickness (2.1, p < 0.0001), irregularity (1.89, p < 0.0001) and overall opinion (1.58, p = 0.0003). Conclusion: Current management options for hypertrophic scarring have limited evidence. Laser therapy presents a minimally invasive procedure that can be completed under topical anaesthetic and has shown to be effective following a single treatment of combined carbon dioxide laser and intense pulsed light device therapy. Lay Summary: Many people will suffer a burn injury throughout their life and up to almost 3 out of 4 people with burn injuries will suffer from hypertrophic scars (a thickened, red and itchy scar). These scars cause distress both due to their appearance and their reduction of function, particularly over a joint or muscle. Laser therapy, in which different wave lengths of light (pulsed light) or gas (carbon dioxide) target the scar, has been found to be effective and have minimal side effects in the management of hypertrophic scars. While individual lasers have been assessed and found to be effective and low risk, the combined use of multiple lasers on the same scar has not been extensively studied. We studied the effectiveness of both light and gas laser therapies on hypertrophic scars. Patients with hypertrophic scars completed a questionnaire that focused on their perspective of their scar (pain, itch, stiffness, thickness, irregularity, overall opinion) prior to the treatment. The patients then underwent laser therapy (with local anaesthetic gel) with either pulsed light and/or carbon dioxide (gas) laser. The type of laser used was decided by the clinician performing the therapy depending on scar location and thickness. Patients then re-completed the subjective survey six weeks following the laser therapy, and the results compared. We learnt that laser therapy (both light, gas and a combination of both) are effective (and low risk) in reducing the subjective burden of the scar for the patient.
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Tidal ventilation is essential in supporting the transition to air-breathing at birth, but excessive tidal volume (VT) is an important factor in preterm lung injury. Few studies have assessed the impact of specific VT levels on injury development. Here, we used a lamb model of preterm birth to investigate the role of different levels of VT during positive pressure ventilation (PPV) in promoting aeration and initiating early lung injury pathways. VT was delivered as 1) 7 mL/kg throughout (VTstatic), 2) begun at 3 mL/kg and increased to a final VT of 7 mL/kg over 3 min (VTinc), or 3) commenced at 7 mL/kg, decreased to 3 mL/kg, and then returned to 7 mL/kg (VTalt). VT, inflating pressure, lung compliance, and aeration were similar in all groups from 4 min, as was postmortem histology and lung lavage protein concentration. However, transient decrease in VT in the VTalt group caused increased ventilation heterogeneity. Following TMT-based quantitative mass spectrometry proteomics, 1,610 proteins were identified in the lung. Threefold more proteins were significantly altered with VTalt compared with VTstatic or VTinc strategies. Gene set enrichment analysis identified VTalt specific enrichment of immune and angiogenesis pathways and VTstatic enrichment of metabolic processes. Our finding of comparable lung physiology and volutrauma across VT groups challenges the paradigm that there is a need to rapidly aerate the preterm lung at birth. Increased lung injury and ventilation heterogeneity were identified when initial VT was suddenly decreased during respiratory support at birth, further supporting the benefit of a gentle VT approach.NEW & NOTEWORTHY There is little evidence to guide the best tidal volume (VT) strategy at birth. In this study, comparable aeration, lung mechanics, and lung morphology were observed using static, incremental, and alternating VT strategies. However, transient reduction in VT was associated with ventilation heterogeneity and inflammation. Our results suggest that rapidly aerating the preterm lung may not be as clinically critical as previously thought, providing clinicians with reassurance that gently supporting the preterm lung maybe permissible at birth.
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BACKGROUND: The impact of different respiratory strategies at birth on the preterm lung is well understood; however, concerns have been raised that lung recruitment may impede cerebral haemodynamics. This study aims to examine the effect of three different ventilation strategies on carotid blood flow, carotid artery oxygen content and carotid oxygen delivery. METHODS: 124-127-day gestation apnoeic intubated preterm lambs studied as part of a larger programme primarily assessing lung injury were randomised to positive pressure ventilation with positive end-expiratory pressure (PEEP) 8 cmH2O (No-RM; n = 12), sustained inflation (SI; n = 15) or dynamic PEEP strategy (DynPEEP; maximum PEEP 14 or 20 cmH2O, n = 41) at birth, followed by 90 min of standardised ventilation. Haemodynamic data were continuously recorded, with intermittent arterial blood gas analysis. RESULTS: Overall carotid blood flow measures were comparable between strategies. Except for mean carotid blood flow that was significantly lower for the SI group compared to the No-RM and DynPEEP groups over the first 3 min (p < 0.0001, mixed effects model). Carotid oxygen content and oxygen delivery were similar between strategies. Maximum PEEP level did not alter cerebral haemodynamic measures. CONCLUSIONS: Although there were some short-term variations in cerebral haemodynamics between different PEEP strategies and SI, these were not sustained. IMPACT: Different pressure strategies to facilitate lung aeration at birth in preterm infants have been proposed. There is minimal information on the effect of lung recruitment on cerebral haemodynamics. This is the first study that compares the effect of sustained lung inflation and dynamic and static positive end-expiratory pressure on cerebral haemodynamics. We found that the different ventilation strategies did not alter carotid blood flow, carotid oxygen content or carotid oxygen delivery. This preclinical study provides some reassurance that respiratory strategies designed to focus on lung aeration at birth may not impact cerebral haemodynamics in preterm neonates.