Lesión pulmonar autoinfligida por el paciente / Patient self inflicted lung injury / Lesão pulmonar autoinfligida pelo paciente

Resumen: La optimización del esfuerzo espontáneo en la ventilación mecánica tiene un lugar central en la Unidad de Cuidados Intensivos; aporta beneficios a los pacientes como la mejoría en el intercambio de gases, ayuda a recuperar la función del diafragma y el mantenimiento de los músculos periféricos. Por otro lado, también puede estar asociado al deterioro de la oxigenación y la lesión pulmonar. El incremento del impulso respiratorio neural aumenta el esfuerzo muscular inspiratorio, lo que condiciona presiones de distensión pulmonar lesivas, que en el contexto del síndrome de insuficiencia respiratoria aguda es de vital relevancia, ya que puede provocar el colapso y la sobredistensión regional alveolar de forma cíclica, con distribución heterogénea del estrés y tensión pulmonar. Existen tres mecanismos de lesión pulmonar por esfuerzo espontáneo: sobredistensión, aumento de la perfusión pulmonar y asincronía paciente-ventilador. La lesión pulmonar causa fuga capilar, edema pulmonar y alteración del intercambio de gases. Esto conduce a un aumento del impulso respiratorio y mayores volúmenes corrientes de las propias respiraciones espontáneas del paciente, que provocan fuga capilar y mayor daño pulmonar de forma similar a la lesión pulmonar inducida por ventilador.

Abstract: The optimization of spontaneous effort in mechanical ventilation has a central place in the intensive care unit; provides benefits to patients such as improved gas exchange, helps to regain function of the diaphragm and maintenance of peripheral muscles. On the other hand, it can also be associated with impaired oxygenation and lung injury. The increase in the neural respiratory drive increases the inspiratory muscular effort, conditioning damaging pulmonary distension pressures, which in the context of acute respiratory distress syndrome is of vital importance, since it can cause collapse and regional alveolar overdistention in a cyclical way. with heterogeneous distribution of pulmonary stress and strain. There are three mechanisms of lung injury due to spontaneous effort: overdistention, increased pulmonary perfusion, and patient-ventilator asynchrony. Lung injury causes capillary leakage, pulmonary edema, and impaired gas exchange. This leads to increased respiratory drive and higher tidal volumes of the patient's own spontaneous breaths, causing capillary leakage and increased lung damage like ventilator-induced lung injury.

Resumo: A otimização do esforço espontâneo na ventilação mecânica tem lugar central na unidade de terapia intensiva; Proporciona benefícios aos pacientes como melhora nas trocas gasosas, auxilia na recuperação da função do diafragma e na manutenção da musculatura periférica. Por outro lado, também pode estar associada ao deterioro da oxigenação e lesão pulmonar. O incremento do impulso respiratório neural aumenta o esforço muscular inspiratório, condicionando pressões de distensão pulmonar prejudiciais, o que no contexto da síndrome de insuficiência respiratória aguda é de vital relevância, pois pode causar colapso e hiperdistensão alveolar regional de forma cíclica, com distribuição heterogênea do estresse e tensão pulmonar. Existem três mecanismos de lesão pulmonar espontânea por esforço: hiperdistensão, aumento da perfusão pulmonar e assincronia paciente-ventilador. A lesão pulmonar causa vazamento capilar, edema pulmonar e troca gasosa prejudicada. Isso leva ao aumento do impulso respiratório e aos volumes correntes mais altos das próprias respirações espontâneas do paciente, causando vazamento capilar e danos pulmonares adicionais semelhantes aos danos pulmonares induzidos pelo ventilador.

Effect of different durations of overdistention on rat bladder function and morphology

We investigated the contribution of the duration of overdistention (DOD) to rat bladder function and morphology and explored its possible molecular mechanisms. Bladder overdistention was induced in male Sprague-Dawley rats (200-250 g) by an infusion of saline. Forty rats were divided into 5 groups submitted to different DOD, i.e., 1, 2, 4, and 8 h, and control. Bladder function was evaluated by cystometry. Morphological changes were observed by light and transmission electron microscopy. Compared to control (44.567 ± 3.472 cmH2O), the maximum detrusor pressure of groups with 2-, 4- and 8-h DOD decreased significantly (means ± SEM): 32.774 ± 3.726, 31.321 ± 2.847, and 29.238 ± 3.724 cmH2O. With the increase of DOD, inflammatory infiltration and impairment of ultrastructure were more obvious in bladder tissue. Compared to control (1.90 ± 0.77), the apoptotic indexes of groups with 1-, 2-, 4-, and 8-h DOD increased significantly (6.47 ± 2.10, 10.66 ± 1.97, 13.91 ± 2.69, and 18.33 ± 3.28%). Compared to control (0.147 ± 0.031/0.234 ± 0.038 caspase 3/β-actin and Bax/Bcl-2 ratios), both caspase 3/β-actin and Bax/Bcl-2 ratios of 1-, 2-, 4-, and 8-h DOD increased significantly (0.292 ± 0.037/0.508 ± 0.174, 0.723 ± 0.173/1.745 ± 0.471, 1.104 ± 0.245/4.000 ± 1.048, and 1.345 ± 0.409/8.398 ± 3.332). DOD plays an important role in impairment of vesical function and structure. With DOD, pro-apoptotic factors increase and anti-apoptotic factors decrease, possibly contributing to the functional deterioration and morphological changes of the bladder.

Clinical Results of Overdistention in the Treatment of Interstitial Cystitis / 대한비뇨기과학회지

Interstitial cystitis is prevalent in the 5th decade women, characterized by frequency, urgency and pelvic pain. To diagnose interstitial cystitis, NIH diagnostic criteria was used. Patients underwent overdistention and all patients were evaluated with IPSS symptom score and urodynamic study in preoperative period, post operative(POD) 1 week and 1 month. The age distribution was 4th decade in 1 patient, 5th decade in 3, 6th decade in 2, 7th decade in 4 and then above 7th decade in 2. Symptom durations was less than 7 years in 7 patients, between 7-10 years in 2 and more than 10 years in 3. Changes in bladder irritative symptom score between preop. and POD 1 week, and preop. and POD 1 month were 6.00+/-4.40(p0.05) but statistically insignificant. However, the change between pre op. and POD 1 month was 97.45+/-90.29(p<0.05) with statistical significance. Difference in maximal capacity between preop. and POD 1 week was statistically significant as 87.55+/-126.39(p<0.05). Bladder functional capacity changes between with and without anesthesia was statistically significant(p<0.05) Postop. complications were bladder rupture in 1 case, and hematuria in 12. The results of overdistention was useful in the diagnosis and treatment of interstitial cystitis. Then more evaluation and follow up will be needed.