patients following major burn injury often require artificial airway management and mechanical ventilation for prolonged periods due to inability of self - contained airway protection , persistence of excessive secretions , and insufficient spontaneous ventilation . therefore a deep continuous analgesia is required . in patients with extensive cutaneous burns capillary leak occurs not only at the injured site , but also in regions distant from the injury , . vascular hyperpermeability leads to lung edema formation due to an increased transpulmonary fluid flux ( lung lymph flow ) and lung water content , . these abnormalities are associated with a subsequent increase in ventilatory pressures and a fall in arterial partial pressure of oxygen ( pao2)/inspiratory oxygen concentration ( fio2)-ratio ( pfr ) . tracheostomy ( ts ) is frequently performed in critically ill and burned patients and plays an integral role in airway management . in 1989 , the american college of chest physicians consensus statement on artificial airways in patients receiving mechanical ventilation stated that translaryngeal intubation ( tli ) is preferred for patients requiring up to 10 days of mechanical ventilation . in patients with an anticipated need for artificial airway ventilation for longer than 21 days , tracheostomy is recommended . in all other patients , timing of ts is left to daily assessment and physician 's preference . in 1994 , the american - european consensus conference ( aecc ) introduced pfr to separate the adult respiratory distress syndrome ( ards ) patients into two stages . situations with pfr < 300 are classified as acute lung injury ( ali ) and patients with pfr < 200 as ards . neither positive end - expiratory pressure ( peep ) nor fio2 settings were recommended . we performed a retrospective analysis of 20 patients which received open surgical ts after burn injury during the last 2 years . in all patients a i to ii inhalation injury was diagnosed by bronchoscopy on admission . male patients were ventilated by standard with a   8.5 mm ( internal diameter ) endotracheal tube or after ts with a 9 mm ( internal diameter ) tracheostomy tube . female patients were ventilated by standard with a 7.5 mm ( internal diameter ) endotracheal tube or after ts with an 8 mm ( internal diameter ) tracheostomy tube . patients were ventilated with a tidal volume of 5 to 7 ml / kg bodyweight . we analyzed patients characteristics ( age , sex , totally burned surface area ( tbsa ) , abbreviated burned severity index ( absi ) ) and mean ventilation parameters ( fio2 , peak inspiratory pressure ( pip ) , pfr , pulmonary resistance , peep ) 8 hours before and after ts . all patients were in a supine position during the analyzed period and were transferred in to a 60-lateral position every 60120 minutes . after dermal incision ( 23 cm cranial to the jugulum ) the thyroidal isthmus was identified and separated from the surrounding tissue . in the next step the trachea was exposed and a tracheal incision was performed . after careful removal of the endotracheal tube patients with a known pulmonary disease or an inhalation injury iii were excluded from this study . statistical analysis was performed using wilcoxon - singed - ranks - test ( spss 15.0 , spss inc . , mean age of the 6 women and 14 men was 5219 years ( minimum : 21 years ; maximum : 83 years ) . mean total burned surface area ( tbsa ) was 3619% ( minimum : 12% ; maximum : 75% ) . mean abbreviated burned severity index ( absi ) was 8.32.2 with a range from 4 to 12 ( table 1 ( tab . 1 ) ) . mechanical ventilation was required in a mean of 14.34.8 days ( minimum : 5 days ; maximum : 24 days ) . surgical ts was performed on day 74 with a range of day 2 to day 20 . mean endotracheal tube size was 8.20.47 mm and mean tracheal tube size was 8.70.47 mm ( p<0.001 ) . fio2 was reduced after ts ( tli vs. ts : 4110% vs. 3410% ; p<0.001 ) . pfr increased significantly after ts ( tli vs. ts : 25360 mmhg/% vs. 32496 mmhg/% ; p<0.001 ( figure 1 ( fig . pip was significantly reduced after ts ( tli vs. ts : 265 mmhg vs. 224 mmhg ; p<0.001 ( figure 2 ( fig . peep was also reduced significantly after ts ( tli vs. ts : 8.42 mmhg vs. 7.12 mmhg ; p=0.003 ( figure 3 ( fig . a significant reduction of pulmonary resistance was observed ( tli vs. ts : 173 mmh2o / l / s vs. 112 mmh2o / l / s ; p<0.001 ( figure 4 ( fig . mechanical ventilation  even if sometimes life - saving  has its negative side effects . marini et al . described in a review the potential diffuse lung injury due to mechanical ventilation . they also postulated a mechanism that could potentially extend primary focal lung injury by airway propagation . the ventilation strategy described by amato et al . intends to minimize shear stress in the lung tissue during inspiration . hereby pulmonary tissue barotrauma and mortality are reduced because of lower tidal volume ( < 6ml / kg ) and driving pressures , permissive hypercapnia , and preferential use of pressure - limited ventilatory modes . ts ( surgical or dilatative ) is described to have its benefit in case of suspected prolonged ventilation . ts has its advantages compared with tli , including reduced laryngeal alteration , reduced inspiratory load , better patient tolerance , and ease of nursing . therefore recommendations are given by the american college of chest physicians consensus statement   and the american - european consensus conference . patients that can benefit from prone position sessions are those with the most severe ards and those with dorsal lung infiltrates , . inhalation of hot air ( over 500c ) or steam can also induce pulmonary burns . the severity of inhalation injury can be classified in three categories ( table 3 ( tab . ts was realized according to the american college of chest physicians consensus statement on artificial airways in patients receiving mechanical ventilation . we demonstrate the early beneficial post - ts effects on mechanical ventilation parameters in severely burned patients . we found a significant pfr - elevation within 8 hours after ts although   fio2 was reduced . furthermore significant decreases in pip , peep and pulmonary resistance were measured after ts . despite post - ts reduction of ventilation invasiveness ( i. e. pip , fio2 and peep ) the increased internal diameter of the tracheal tube after ts may have contributed to the early postoperative benefits on mechanical ventilation . especially pip , peep and pulmonary resistance can be influenced by a larger tube diameter . but increased oxygen delivery after ts can not be explained by the larger internal tube diameter . efforts to decrease alveolar over - distension have emphasized the global reduction of inspiratory pressures and their resultant ventilating volumes . it has been reported , that even short periods of high - pressure mechanical ventilation can be harmful to injured as well as healthy lungs . high pip can lead to progressive impairment in pulmonary mechanics , lung function , acute respiratory failure , and alveolar cellular dysfunction . several studies demonstrated the impact of pip and fio2-elevation to pfr , which is used as parameter for oxygen delivery in critically ill patients , , , , . bolivar et al . showed a reduced carinal pip in an experimental study after tracheostomy . we registered a significant pip - decrease within 8 hours after ts . on the other hand high peep we postulate that due to ts , vili can be reduced or even be avoided . this safe surgical procedure reduces distal - to - proximal airway propagation of initially focal injured / infected pulmonary areas . the ideal ventilation strategy , type of artificial airway ( translaryngeal intubation vs. tracheostomy ) and timing of ts griffiths et al . showed that early tracheostomy in critically ill patients could shorten the duration of mechanical ventilation and the length of stay in intensive care in a meta - analysis in 2005 . therefore , it should be investigated in the future whether an initially performed ts at admission to a burn unit has a beneficial effect on the pulmonary compromised severely burned patient . the interpretation of the results of the present study is limited due to retrospective study design , small number of patients , the short time period measured and the lack of a control comparison group without ts . the interpretation of the results of the present study is limited due to retrospective study design , small number of patients , the short time period measured and the lack of a control comparison group without ts .
purpose : in patients with major burn injuries mechanical ventilation is often required for longer periods . 
 tracheostomy ( ts ) plays an integral role in airway management . 
 we investigated the effect of ts on ventilation parameters within 8 hours after ts.materials : a retrospective analysis of severely burned patients admitted to the burn unit of a german university hospital was performed . 
 ventilation parameters 8 hours before and after ts were registered . results : a retrospective analysis of 20 patients which received surgical ts was performed . 
 mean age was 5219 years . 
 mean abbreviated burned severity index ( absi ) was 8.32.2 . 
 a mechanical ventilation was required for 14.34.8 days . 
 ts was performed on day 74 . 
 inspiratory oxygen concentration ( fio2 ) ( p<0.001 ) , peak inspiratory pressure ( p<0.001 ) , positive end - expiratory pressure ( p=0.003 ) and pulmonary resistance ( p<0.001 ) were reduced significantly after ts . 
 the arterial partial pressure of oxygen / fio2-ratio increased significantly after ts ( p<0.001).conclusions : we demonstrate that ts reduces invasiveness of ventilation in severely burned patients and by this can optimize lung protective ventilation strategy .