Secondary effects of femoral instrumentation on pulmonary physiology in a standardised sheep model: what is the effect of lung contusion and reaming?

Intramedullary nailing is the treatment of choice for patients with femoral shaft fractures. However, there is an ongoing debate in multiple trauma patients with associated lung contusion when primary or secondary definitive stabilisation of the long bone fracture should be performed, as nailing is thought to play an important role in the pathogenesis of adult respiratory distress syndrome (ARDS). In a standardised sheep model, this study aimed to quantify the development of acute pulmonary endothelial changes, to assess the activation of polymorphonuclear leucocytes (PMNL) and to observe the effects on the coagulation system associated with the reamed nailing procedure. Furthermore, the effect of coexisting lung contusion in an experimental model was evaluated. The animals were randomly assigned to one of four different groups (6 animals/group). In control groups, only a sham operation (thoracotomy) was performed, whereas in study groups, lung contusion was induced prior to femoral stabilisation either by external fixation or reamed femoral nailing. Using bronchoalveolar lavage (BAL) pulmonary permeability changes were quantified and PMNL activation was assessed by chemiluminescence. Additionally PMNL diapedesis and interstitial lung oedema were determined by histological analysis. All animals were sacrificed 4 h after the start of the femoral instrumentation. Without an associated lung injury, instrumentation of the femoral canal with the reamed nailing technique induced a transient increase in pulmonary permeability. In the face of an induced lung contusion, reamed femoral nailing resulted in significant increases in PMNL activation, pulmonary permeability and interstitial lung oedema, compared with external fixation. Without pulmonary contusion, reaming of the femoral canal was associated with a transient increase in pulmonary permeability. This was exacerbated in the presence of lung contusion along with increased PMNL activation. External fixation did not provoke similar changes. The findings of this study support the view that reaming of the femoral canal should be avoided in polytrauma patients with severe chest trauma as it could act as an additional stimulus for adverse outcome. Temporary external fixation appears to be a safe method for fracture stabilisation until inflammatory and coagulatory disturbances after trauma have been normalized.     

Blunt chest trauma

Summary Blunt chest trauma is the leading cause of thoracic injuries in Germany, penetrating chest injuries are rare. Hereby, single or multiple rib fractures, hemato-pneumothorax and pulmonary contusion represent the most common injuries. The early managment of thoracic injuries consists of detection and sufficient therapy of acute life threatening situations like tension pneumothorax, acute respiratory insufficiency or severe intrathoracic bleeding. Most of the isolated thoracic injuries are adequately treated by conservative means, sufficient analgesia, drainage of intrapleural air or blood, physiotherapy and clearance of bronchial secretions provided; operative intervention is rarely indicated. In multiple injured patients however, severe blunt chest trauma and especially pulmonary contusion negatively affects outcome with a significant increase of morbidity and mortality. Hence, patients with this combination of pulmonary injuries, such as lung contusion and associated severe injuries, carry a particular high risk of respiratory failure, ARDS and MOF with a considerable mortality. Therefore, early exact diagnosis of all thoracic injuries is essential and can be achieved by thoracic computed tomography, which becomes more and more popular in this setting. Early intubation and PEEP-ventilation, alternate prone and supine positioning of multiple injured patients with lung contusion and differentiated concepts of volume- and catecholamine therapy represent the basic therapeutic principles. Additionally, the entire early trauma management of multiple injured patients must focus on the presence of pulmonary contusion. Every additional burden on their pulmonary microvascular system like microembolisation during femoral nailing, the trauma burden of extended surgery or mediator release in septic states may cause rapid decompensation and organ failure and therefore, has to be avoided.      

Acute respiratory distress syndrome criteria in trauma patients: why the definitions do not work

BACKGROUND: The international consensus definitions for acute respiratory distress syndrome (ARDS) have formed the basis for recruitment into randomized, controlled trials and, more recently, standardized the protocols for ventilatory treatment of acute lung injury. Although possibly appropriate for sepsis-induced ARDS, these criteria may not be appropriate for posttraumatic ARDS if the disease patterns are widely divergent. This study tests the hypothesis that standard ARDS criteria applied to the trauma population will capture widely disparate forms of acute lung injury and are too nonspecific to identify a population at risk for prolonged respiratory failure and associated complications. METHODS: Patients with and Injury Severity Score > or = 16 ventilated for > 12 hours were prospectively enrolled. Clinical data, including elements of cardiovascular, renal, hepatic, hematologic, neurologic, and pulmonary function, were collected daily. Two hundred fifty-four patients were enrolled over a 36-month period, of whom 70 met the consensus definitions of ARDS. Patients from whom support was withdrawn within 48 hours were excluded. The remaining 61 patients were stratified into two groups on the basis of intubation (n = 12) days. RESULTS: There was considerable disparity in severity and clinical course. A mild, limited form of ARDS was characterized by earlier onset (group 1, 2 days; group 2, 4 days; p = 0.002), fewer intubation days (7 days vs. 28 days; p < 0.001), and less severe derangements in lung mechanics. A significant difference between the two groups was also seen in systemic inflammatory response syndrome score, incidence of sepsis, and incidence of multiple organ failure. CONCLUSION: The criteria for ARDS, when applied to the trauma population, capture a widely disparate group and has poor specificity for identifying patients at risk. Recruitment of trauma patients for ARDS studies or preemptive ventilatory management based solely on these criteria may be ill-advised.     

肺挫伤患者呼吸功能障碍的发病因素及治疗

目的:探讨导致肺挫伤患者呼吸功能障碍的发病因素,提高肺挫伤的治疗水平。方法:把影响肺挫伤患者呼吸功能的因素分为:外呼吸因紊,肺实质损伤,继发性病理因素影响。分析它们的特点,用于指导治疗252例肺挫伤患者并总结经验。结果:本资料ARDS发生率11.11％,死亡率6.35％均较文献报道低。结论:导致肺挫伤患者肺功能障碍病因复杂,合理应用病因分类有助于临床治疗。     

严重肺挫伤合并急性呼吸窘迫综合征的诊治

目的提高对严重肺挫伤合并急性呼吸窘迫综合征(ARDS)的认识.方法对24例严重肺挫伤合并ARDS患者的临床资料进行回顾性分析.结果本组患者ARDS占同期外科ICU严重肺挫伤患者(47例)的51.1%,全组死亡6例,死亡率25%,24例均给予机械通气;并发肺炎占12例,感染率50%.结论救治严重肺挫伤合并ARDS患者的关键在于对导致ARDS的原发病肺挫伤有充分认识.早期诊断和治疗,正确使用呼吸机,正确治疗多发性损伤是减少ARDS死亡率的有效方法.     

Surfactant administration in acute respiratory failure]

We report the case of a 21-year-old man who developed adult respiratory distress syndrome (ARDS) after severe lung contusion due to a car accident. At the scene of the accident the patient was awake and oriented, but there were signs of hypoxaemia (SaO2 by pulse oximetry: 86%). The trachea was intubated in the emergency room and, after diagnosis of multiple rib fractures on the right side (the patient nos. 4-11) and emergency treatment, was extubated 16 h later. During spontaneous breathing there was no improvement of pulmonary function, and the patient was transferred to the intensive care unit 5 days later and reintubated because of acute respiratory failure. He then developed the signs of severe ARDS. No improvement occurred during conventional ventilatory treatment including inversed-ratio ventilation, high-frequency ventilation, and ventilation via a double-lumen tube. On day 15 a bovine surfactant preparation (38 mg/kg body wt.) was instilled into both lungs. Initially there was deterioration of the pulmonary function, probably due to crusts in the bronchial mucous membrane. After aspiration of the crusts at bronchoscopy, there was progressive respiratory improvement. The inspired oxygen concentration and PEEP level could be reduced, and the ventilatory ratio normalised within 14 days. This therapeutic intervention improved pulmonary function and probably led to the successful outcome after 36 days of ventilatory support.     

Pulmonary damage after intramedullary femoral nailing in traumatized sheep--is there an effect from different nailing methods?

Stabilization of femoral shaft fractures is a controversial issue in the management of patients with multiple trauma. Intramedullary nailing usually is preferred primarily; in recent years, however, pulmonary complications (e.g., ARDS) have been reported that were attributed to the reaming procedure. To study the effects of different nailing methods in a model of severe trauma, hemorrhagic shock and lung contusion were created at day 1 in sheep prepared by the method described by Staub. After recuperation (day 3) the animals in the study group (group 1) underwent intramedullary nailing of a closed femur without prior reaming; group 2 was treated with reaming and nailing according to AO standards. The reaming procedure led to an acute increase of pulmonary arterial pressure only in group 2 (19.8 +/- 2.1 to 31.0 +/- 4.6 mm Hg). Pulmonary triglyceride levels increased at parallel time points from 18.27 +/- 2.3 to 33.04 +/- 7.37 mg/dL only in group 2. Stimulatory capacity of polymorphonuclear leukocytes (PMNL) increased in the study group and decreased in controls (group 1: 2.652 +/- 0.23 x 10(6) cpm to 3.387 +/- 1.34 x 10(6) cpm; group 2: 2.699 +/- 0.34 x 10(6) cpm to 2.460 +/- 0.187 x 10(6) cpm). Intramedullary nailing caused an increase of lung capillary permeability in both groups; in the study group less damage was seen (group 1: 0.390 +/- 0.0006 to 0.354 +/- 0.011; group 2: 0.391 +/- 0.0004 to 0.336 +/- 0.015; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

肺挫伤的诊断与治疗进展

肺挫伤在全身多发伤患者尤其是合并胸部钝性损伤患者中很常见,由于常合并肋骨骨折、血气胸、腹部脏器伤、四肢骨折及部分病例早期临床表现不典型,肺挫伤常被漏诊,以至于发展为肺部感染、肺不张,甚至是急性呼吸窘迫综合征(ARDS),临床病死率较高。国内外学者均主张早期准确诊断、综合治疗以提高疗效,降低病死率,但具体治疗策略尚未统一。笔者搜集整理了近年来国内外有关肺挫伤治疗的文献后,对肺挫伤诊断治疗的新进展进行综述。     

Early intramedullary nailing of lower extremity fracture and respiratory function in polytraumatized patients with a chest injuryA retrospective study of 61 patients

Background?The optimal treatment of diaphyseal fractures of the lower extremities in patients who also have serious chest injuries is not known. Patients and methods?We retrospectively evaluated the effect of an early intramedullary nailing (IMN) of femur or tibia fractures on respiratory function in 61 consecutive polytraumatized patients with unilateral or bilateral pulmonary contusion (thoracic AIS=3) admitted to our trauma intensive care unit between January 2000 and June 2001. 27 patients had a diaphyseal fracture of at least one long bone of the lower extremity, which was treated with IMN within 24 hours of admission. Results?We found no difference between patients with or without a lower extremity fracture regarding the length of ventilator treatment, oxygenation ratio (PaO2/FiO2) or in the incidence of acute respiratory distress syndrome (ARDS), pneumonia, multi-organ failure or mortality. Interpretation?In this retrospective study, IMN of a long bone fracture in a patient with multiple injuries and with a coexisting pulmonary contusion did not impair pulmonary function or outcome.     

Thoracic Trauma Severity score on admission allows to determine the risk of delayed ARDS in trauma patients with pulmonary contusion

BackgroundPulmonary contusion is a major risk factor of acute respiratory distress syndrome (ARDS) in trauma patients. As this complication may appear after a free interval of 24–48 h, detection of patients at risk is essential. The main objective of this study was to assess the performance of the Thoracic Trauma Severity (TTS) score upon admission in predicting delayed ARDS in blunt trauma patients with pulmonary contusion.MethodsAll blunt thoracic trauma patients admitted consecutively to our trauma centre between January 2005 and December 2009 were retrospectively included if they presented a pulmonary contusion on the admission chest computed tomography scan. Main outcome measure was the presence of moderate or severe ARDS (PaO₂/FiO₂ ratio ≤ 200) for 48 h or more. The global ability of the TTS score to predict ARDS was studied by ROC curves with a threshold analysis using a grey zone approach.ResultsOf 329 patients studied (75% men, mean age 36.9 years [SD 17.8 years], mean Injury Severity Score 21.7 [SD 16.0]), 82 (25%) presented with ARDS (mean lowest PaO₂/FiO₂ ratio of 131 [SD 34]). The area under the ROC curves for the TTS score in predicting ARDS was 0.82 (95% CI 0.78–0.86) in the overall population. TTS scores between 8 and 12 belonged to the inconclusive grey zone. A TTS score of 13–25 was found to be independent risk factors of ARDS (OR 25.8 [95% CI 6.7–99.6] P < 0.001).ConclusionsAn extreme TTS score on admission accurately predicts the occurrence of delayed ARDS in blunt thoracic trauma patients affected by pulmonary contusion. This simple score could guide early decision making and management for a non-negligible proportion of this specific population.     

Early intramedullary nailing of lower extremity fracture and respiratory function in polytraumatized patients with a chest injury: a retrospective study of 61 patients

BACKGROUND: The optimal treatment of diaphyseal fractures of the lower extremities in patients who also have serious chest injuries is not known. PATIENTS AND METHODS: We retrospectively evaluated the effect of an early intramedullary nailing (IMN) of femur or tibia fractures on respiratory function in 61 consecutive polytraumatized patients with unilateral or bilateral pulmonary contusion (thoracic AIS=3) admitted to our trauma intensive care unit between January 2000 and June 2001. 27 patients had a diaphyseal fracture of at least one long bone of the lower extremity, which was treated with IMN within 24 hours of admission. RESULTS: We found no difference between patients with or without a lower extremity fracture regarding the length of ventilator treatment, oxygenation ratio (PaO2/FiO2) or in the incidence of acute respiratory distress syndrome (ARDS), pneumonia, multi-organ failure or mortality. INTERPRETATION: In this retrospective study, IMN of a long bone fracture in a patient with multiple injuries and with a coexisting pulmonary contusion did not impair pulmonary function or outcome.     

Respiratory distress following major trauma. Predictive value of blood coagulation tests

We have evaluated the use of laboratory parameters to predict the risk of adult respiratory distress syndrome (ARDS) at an early stage after major trauma. Patients with lung contusion were excluded. Five of 29 patients fulfilled our criteria of ARDS, i.e. PaO2/FiO2 less than or equal to 38. They showed lower platelet counts and antiplasmin as well as a tendency to lower antithrombin III, fibrinogen, and plasminogen. These changes indicated activation of the coagulation and fibrinolytic systems by trauma. The most sensitive indicator of ARDS seemed to be the platelet count, although it was also related to blood loss and amount of blood transfused. Hence the platelet count should be considered in relation to blood replacement in the patient with major trauma. Tentative laboratory values are suggested to indicate risk levels of developing ARDS.     

Der Einfluß des kontinuierlichen axialen Lagewechsels bei der Behandlung des posttraumatischen Lungenversagens (ARDS)

In the treatment of posttraumatic adult respiratory distress syndrome (ARDS) so far no breakthrough has been achieved. In several cases of severe ARDS we have seen improvements of lung function by means of continuous body positioning. We therefore compared the effect of kinetic positioning (KIN) on lung function and hemodynamics in ARDS patients to conventional (KON) supine positioning. 22 ARDS patiens with multiple trauma treated by supportive continuous body positioning (KIN) (KCI-Mediscus) and without continuous positioning (KON) were investigated daily. Pulmonary and systemic hemodynamics were determined on the basis of pulmonary artery catheter measurements. Oxygenation ratio (PaO₂/FiO₂) and pulmonary shunt (Qs/Qt, %) were calculated. Extravascular lung water (EVLW, ml/kg body weight) was determined by double indicator thermodilution technique. Total injury severity by injury severity score (ISS) was 29.6±6 points (KIN) and 31.6±5 points (KON). The oxygenation ratio (PaO₂/FiO₂) increased significantly from 140±45 (day 0) to 237±40 (p<0.05) [day 5] (KIN), in KON patients no improvement (143±48 [day 0], 133±44 [day 5]) was seen (p<0.05 between groups). There were no significant changes of systemic hemodynamics between the groups or compared to day 0. Pulmonary shunt decreased significantly from 26.6±4% (day0) to12.5±2% (day5) (p<0.05) in KIN patients and was 36.6±6% at day 0 and 31.4±2% at day 5 in KON patients (p<0.05 between groups). EVLW was 11.1±2 ml/kg body weight at day 0 and 9.4±1 ml/kg body weight at day 5 (KIN)-EVLW was 12.9±2 ml/kg body weight at day 0 and 17.4±3 ml/kg body weight at day 5 (KON) (not significant). We found no hemodynamic side effects from continuous body positioning. In ARDS-patients submitted to body positioning oxygenation and pulmonary shunt improved significantly and were significantly better compared to those with conventional supine positioning. Continuous body positioning appears to represent a promising supportive treatment regimen in posttraumatic ARDS.     

急性呼吸窘迫综合征患者机械通气相关肺纤维化机制及治疗新进展

背景 机械通气在急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)患者的救治过程中发挥着重要作用,然而机械通气使用不当,可诱发或加重肺损伤,即呼吸机相关性肺损伤,更关键的是机械通气可显著增加ARDS患者肺纤维化的发病率和病死率,有研究报道在ARDS的致死原因中,难以控制的肺纤维化占40％ ～60％. 目的 就ARDS患者机械通气相关肺纤维化的发生机制、防治策略等方面的研究新进展予以综述. 内容 机械通气产生的机械牵张可激活细胞信号通路最终导致肺纤维化的发生发展. 趋向 机械通气导致的肺纤维化已成为ARDS患者预后不良及肺功能下降的重要原因之一,我们应当予以高度重视.随着对其发病机制的不断探索,将为研发有效的防治措施提供更好的理论基础.     

Ventilatory support in patients with ARDS

Adult respiratory distress syndrome remains one of the most lethal conditions treated in surgical and medical intensive care units. Mortality rates of 50 per cent are still reported in recent reviews. Many risk factors are linked with an increased incidence of ARDS, but sepsis and direct pulmonary injury from aspiration, pulmonary contusion, and other forms of trauma are the most commonly associated risk factors. Studies implicate various cellular and chemical mediators associated with acute lung injury. Many pharmacologic agents and various forms of high-frequency ventilation are being studied for their effectiveness in treating ARDS. We consider that the standard treatment continues to be PEEP and mechanical ventilation to reverse hypoxemia linked with the pathophysiologic changes of ARDS. There are no prospective randomized studies comparing the various end points of therapy used clinically at present. We believe, however, that early intervention, with institution of ventilatory support as soon as signs of acute respiratory failure develop, may eliminate some deaths due to progressive hypoxemia leading to the full adult respiratory distress syndrome. Therapy should be started at this time and maintained while the etiologic factors are identified and treated. Minimal ventilatory support should be continued until the primary diseases have resolved and the multisystem impact of the critical illness has lessened. Weaning from inspiratory (IMV) support, manipulation of expiratory pressures (PEEP), and airway control should then be more easily accomplished and more successful in practice.     

腹部闭合性损伤合并肺挫裂伤的治疗

目的 探讨腹部闭合性损伤合并肺挫裂伤的治疗.方法 回顾性分析我院收治28例严重腹部闭合性损伤合并肺挫裂伤病人的诊治临床资料.结果 28例中治愈26例,死亡2例.在治疗过程中并发ARDS 8例,肺炎11例,肺不张4例.结论 严重腹部闭合性损伤合并肺挫裂伤较为常见,积极救治腹部闭合性损伤,重视肺挫裂伤的诊断与处理,胸部X线...     

Acute respiratory distress syndrome in blunt trauma: identification of independent risk factors

Acute respiratory distress syndrome (ARDS) is a major contributor to morbidity and mortality in trauma patients. Although many injuries and conditions are believed to be associated with ARDS independent risk factors in trauma patients and their relative importance in development of the syndrome are undefined. The aim of this project is to identify independent risk factors for the development of ARDS in blunt trauma patients and to examine the contributions of each factor to ARDS development. Patients with ARDS were identified from the registry of a Level I trauma center over a 4.5-year period. Records were reviewed for demographics, injury characteristics, transfusion requirements, and hospital course. Variables examined included age >65 years, Injury Severity Score (ISS) >25, hypotension on admission (systolic blood pressure <90), significant metabolic acidosis (base deficit <-5.0), severe brain injury as shown by a Glasgow Coma Scale score (GCS) <8 on admission, 24-hour transfusion requirement >10 units packed red blood cells, pulmonary contusion (PC), femur fracture, and major infection (pneumonia, empyema, or intra-abdominal abscess). Both univariate and stepwise logistic regression were used to identify independent risk factors, and receiver operating characteristic curve (ROC) analysis was used to determine the relative contribution of each risk factor. A total of 4397 patients having sustained blunt trauma were admitted to the intensive care unit and survived >24 hours between October 1995 and May 2000. Of these patients 200 (4.5%) developed ARDS. All studied variables were significantly associated with ARDS in univariate analyses. Stepwise logistic regression, however, demonstrated age >65 years, ISS >25, hypotension on admission, 24-hour transfusion requirement >10 units, and pulmonary contusion as independent risk factors, whereas admission metabolic acidosis, femur fracture, infection, and severe brain injury were not. Using a model based on the logistic regression equation derived yields better than 80 per cent discrimination in ARDS patients. The risk factors providing the greatest contribution to ARDS development were ISS >25 (ROC area 0.72) and PC (ROC area 0.68) followed by large transfusion requirement (ROC area 0.56), admission hypotension (ROC area 0.57), and age >65 (ROC area 0.54). Independent risk factors for ARDS in blunt trauma include ISS >25, PC, age >65 years, hypotension on admission, and 24-hour transfusion requirement >10 units but not admission metabolic acidosis, femur fracture, infection, or severe brain injury. Assessment of these variables allows accurate estimate of risk in the majority of cases, and the most potent contributors to the predictive value of the model are ISS >25 and PC. Improvement in understanding of which patients are actually at risk may allow for advances in treatment as well as prevention in the future.     

Application of ECMO in multitrauma patients with ARDS as rescue therapy

BACKGROUND: Despite recent advances in critical care management, the mortality of acute respiratory distress syndrome (ARDS) remains high. The final rescue therapy for patients with severe hypoxia refractory to conventional therapy modalities is the extracorporeal gas exchange. METHODS: We report the management of three polytraumatized patients with life-threatening injuries, severe blunt thoracic trauma, and consecutive ARDS treating by extracorporeal membrane oxygenation (ECMO). Two patients suffered a car accident with severe lung contusion and parenychmal bleeding. Bronchial rupture and mediastinal emphysema was found in one of them. Another patient developed ARDS after attempted suicide with multiple fractures together with blunt abdominal and thoracic trauma. RESULTS: All patients were placed on ECMO and could be rapidly stabilized. They were weaned from ECMO after a mean of 114 +/- 27 hours of support without complications, respectively. Mean duration of ICU stay was 37 +/- 23 days. CONCLUSIONS: Quick encouragement of ECMO for the temporary management of gas exchange may increase survival rates in trauma patients with ARDS.     

Pathophysiologic significance of lung granulocytes in human adult respiratory distress syndrome induced by septic or traumatic shock

To evaluate the significance of lung granulocytes in the adult respiratory distress syndrome (ARDS), 12 ARDS patients were studied with bronchoalveolar lavage (BAL) within 4-12 hours after clinical diagnosis of the syndrome. The specificity of pulmonary granulocytes in ARDS was investigated in comparison with five patients requiring ventilator treatment for cardiogenic pulmonary oedema and 17 normal patients about to undergo cholecystectomy. The percentage of granulocytes among recovered BAL cells was significantly higher in ARDS (77 +/- 18, M +/- SD) than in the cardiac (7 +/- 4) or the normal (1.5 +/- 1.0) group. In serial BAL (48-hour intervals) in five ARDS patients, significant reduction of granulocytes 86 +/- 11----32 +/- 10%) accompanied clinical improvement. The percentage of granulocyte in BAL correlated significantly and inversely with the PaO2/FiO2 ratio (r = -0.98), and in ARDS it was significantly higher after septic than after traumatic shock (89 +/- 14 vs. 55 +/- 12). Myeloperoxidase, a specific constituent of neutrophils, was significantly and inversely correlated with PaO2/FiO2 ratio (r = -0.62). The findings suggest a role for activated granulocytes in the lung, with release of tissue-damaging substances, in initial ARDS pathogenesis, notably when the syndrome is sepsis-induced.