Ventilator-associated lung injury (VALI) is an acute lung injury that develops during mechanical ventilation and is termed ventilator-induced lung injury (VILI) if it can be proven that the mechanical ventilation caused the acute lung injury. In contrast, ventilator-associated lung injury (VALI) exists if the cause cannot be proven. VALI is the appropriate term in most situations because it is virtually impossible to prove what actually caused the lung injury in the hospital. Cause
It is generally regarded, based on animal models and human studies, that volutrauma is the most harmful aspect of mechanical ventilation. This may be regarded as the over-stretching of the airways and alveoli.During mechanical ventilation, the flow of gas into the lung will take the path of least resistance. Areas of the lung that are collapsed (atelectasis) or filled with secretions will be underinflated, while those areas that are relatively normal will be overinflated. These areas will become overdistended and injured. This may be reduced by using smaller tidal volumes.During positive pressure ventilation, atelectatic regions will inflate, however, the alveoli will be unstable and will collapse during the expiratory phase of the breath (atelectotrauma). This repeated alveolar collapse and expansion (RACE) is thought to cause VALI. By opening the lung and keeping the lung open RACE (and VALI) is reduced.Another possible ventilator-associated lung injury is known as biotrauma. Biotrauma involves the lung suffering injury from any mediators of the inflammatory response or from bacteremia. Finally oxygen toxicity contributes to ventilator-associated lung injury through several mechanisms including oxidative stress.
Meacham syndrome is a rare genetic disorder which is characterized by lung, diaphragmatic and genitourinary anomalies. Signs and symptoms
Often people with this condition are born with both underdeveloped lungs and a herniated diaphragm. Urinary symptoms include a horseshoe kidney
Genital symptoms are different according to the biological sex of the baby, genetic males (46,XX) usually have pseudohermaphroditism, ambiguous genitalia, and perineal hypospadias. Genetic females (46,XX) often have septate uterus and duplication of the vagina. In some cases, karyotype is needed to know the biological sex of the baby.Additional symptoms include neoplasm, cryptorchidism, ventricular septal defect, atrial septal defect, hernia, patent ductus arteriosus, Tetralogy of Fallot, and penile hypoplasia. Causes
This condition is caused by an autosomal dominant missense mutation in the WT1 gene, in chromosome 11. This was found through two half-siblings reported by Suri et al. Epidemiology
According to OMIM, only 12 cases have been described in medical literature. == References ==