Pre-hospital pleural decompression and chest tube placement after blunt trauma: A systematic review

Transcription

1 Resuscitation (2007) 72, REVIEW ARTICLE Pre-hospital pleural decompression and chest tube placement after blunt trauma: A systematic review Christian Waydhas a,, Stefan Sauerland b a Department of Trauma Surgery, University Hospital Essen, Hufelandstr. 55, Essen, Germany b Institute for Research in Operative Medicine, University of Witten/Herdecke, Ostmerheimer Straße 200, Köln, Germany Received 20 April 2006; received in revised form 13 June 2006; accepted 20 June 2006 KEYWORDS Trauma; Pneumothorax; Tension pneumothorax; Advanced life support (ALS); Thoracostomy; Thoracocentesis Summary Pre-hospital insertion of chest tubes or decompression of air within the pleural space is one of the controversial topics in emergency medical care of trauma patients. While a wide variety of opinions exist medical personnel on the scene require guidance in situations when tension pneumothorax or progressive pneumothorax is suspected. To ensure evidence based decisions we performed a systematic review of the current literature with respect to the diagnostic accuracy in the prehospital setting to identify patients with (tension) pneumothorax, the efficacy and safety of performing pleural decompression in the field and the choice of method and technique for the procedure. The evidence found is presented and discussed and recommendations are drawn from the authors perspective Elsevier Ireland Ltd. All rights reserved. Contents Introduction Methods Results and interpretation Diagnostic requirements and diagnostic accuracy Clinical examination Diagnosis of pneumothorax Diagnosis of tension pneumothorax Indication for decompression of the pleural space A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi: /j.resuscitation Corresponding author. Tel.: ; fax: address: christian.waydhas@uk-essen.de (C. Waydhas) /$ see front matter 2006 Elsevier Ireland Ltd. All rights reserved. doi: /j.resuscitation

2 12 C. Waydhas, S. Sauerland Tension pneumothorax Pneumothorax Chest injury with normal breath sounds Methods to decompress the pleural space Needle decompression: efficiency and complications Surgical decompression: efficiency and complications Chest tube: efficacy and complications Needle decompression versus chest tube Technical considerations Puncture site Needle and tube size Drainage systems Insertion of the needle or chest tube Conflict of interest Acknowledgements References Introduction Pre-hospital insertion of chest tubes or decompression of air within the pleural space is one of the controversial topics in emergency medical care of trauma patients. There is a wide variety of opinions, ranging from complete disapproval as quoted from K. Mattox in the trauma.org discussion forum a few years ago: There is indeed a lot of emotion relating to the ability to perform a technical assault on a patient, including needle decompression in the field. I have found NO, I repeat NO, data which were prospectively collected in a randomised fashion which justifies this dangerous practice. I would strongly recommend that prehospital chest decompression by ANYONE by any method be eliminated until appropriate evidenced based data exist 1 to the recommendation in a recent review that pleural decompression would be life saving standard care: The pre-clinical tension pneumothorax which, even without technical support, is easily recognisable, requires immediate decompression. However, there are a number of patients with thoracic injuries such as serial rib fractures or palpable skin emphysema which may necessitate the insertion of a thoracic tube. 2 The discussion mainly focuses around the ability to identify patients with (tension) pneumothorax reliably, the efficacy and safety of performing pleural decompression in the field and the choice of method and technique for the procedure, i.e. needle decompression, chest tube insertion or others. As is the case with many problems in prehospital emergency medicine, there is little evidence available in terms of randomised trials or high quality prospective studies. In this systematic review we evaluated the available medical literature describing the present knowledge of prehospital chest tube placement and pleural decompression after blunt trauma so that pre-hospital medical personnel may decide on their choice of treatment. Methods The literature search was primarily done in Medline as indicated in Table 1 (last update from November 16, 2005). There were 638 hits, which were all screened in abstract form. Potentially relevant articles were acquired in full text. In addition, the reference list of all publications seen in full text was reviewed for potentially relevant citations not found with the data bank search. The search was completed by a hand search of books and journals not indexed in Medline. All relevant articles were classified in levels of evidence levels (LoE) according to their study design following the suggestions from Sackett et al., 3 separately for diagnostic and therapeutic studies. The level of evidence was determined by the two authors independently and consented, if there was a discrepancy. In addition to the grading based on the methodological criteria of the studies, the relevance of the contents with respect to the pre-hospital setting was also accounted for. Thus, a down-grading was possible, e.g. for therapeutic studies in patients with non-traumatic pneumothorax. 4 7 Finally, the grade of recommendation was determined by the level of evidence: grade A (LoE 1), grade B (LoE 2 or 3) and grade C (LoE 4 or 5). The clinical data were extracted from the articles by the two authors independently and inserted in the tables. A statistical meta-analysis was not done due to the heterogeneity of the studies. To

3 Pre-hospital pleural decompression and chest tube placement 13 Table 1 Medline search terms and results (completed November 16, 2005) Search Search terms Results #1 ( Chest tubes/adverse effects [MESH] OR thoracostomy/adverse effects [MESH]) #2 ( Chest tubes [MESH] OR thoracostomy [MESH]) AND thoracic injuries [MESH] #3 ( Hemopneumothorax/therapy [MESH] OR pneumothorax/ therapy [MESH]) AND ( emergency medical services [MESH] OR prehospital OR pre-hospital OR pre-clinical OR pre-clinical) #4 ( Hemopneomothorax/diagnosis [MESH] OR pneumothorax/ diagnosis [MESH]) AND wounds and injuries [MESH] AND physical examination [MESH] #5 ( Thoracostomy/instrumentation [MESH] OR thoracostomy/ methods [MESH]) OR ( chest tubes/classification [MESH] OR chest tubes/standards [MESH]) #6 ( Thoracostomy [MESH] OR chest tubes [MESH]) AND (clamp* OR disconnect* OR pinch*) #7 ( Thoracostomy [MESH] OR chest tubes [MESH]) AND Clinical Trial[ptyp] #8 #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR # evaluate diagnostic accuracy positive and negative likelihood ratios were calculated from the sensitivities and specificities given in the articles. They were applied to a hypothetical pre-test probability for the presence of pneumothorax in chest injured patients of 10%. Results and interpretation Diagnostic requirements and diagnostic accuracy Clinical examination Scientific evidence is not available to determine whether pre-hospital clinical examination is necessary, or not, to improve outcome of patients with potential trauma to the chest. However, physical examination is a pre-requisite for all decisions about medical management of patients and this opinion has never been challenged. Recommendations: A clinical examination of patients with suspected chest injury appears warranted (grade C recommendation). It should include the determination of the respiratory rate and auscultation of both lungs (grade B recommendation). Inspection and palpation of the thorax as well as monitoring of the airway pressure of ventilated patients and pulse oximetry may be helpful (grade C recommendation). Assuming that some kind of pre-hospital examination is useful in this setting, there are several publications suggesting what should be looked for. These focus on auscultation, determination of the respiratory rate and the evaluation of pain in the thorax, while other types of examination have not been studied in detail. Following the initial check of the vital signs, auscultation of the lung (presence of breathing sounds and lateralisation) (LoE 2) and determination of the respiratory rate (LoE 3) 8 11 have been correlated either with significant pathological findings or with medical decision making and therapeutic consequences, e.g. performing pleural decompression or transport to a certain level of trauma centre. Similarly, palpation (searching for subcutaneous emphysema, localised thoracic pain, crepitation, instability of the thorax) and monitoring of inspiratory pressure during mechanically ventilation and arterial oxygen saturation have been evaluated in one study and found to be helpful (LoE 4). 12 Inspection of the thorax (looking for signs of injury, symmetry of the thorax and breathing movements, inverse breathing, jugular vein filling) has been advocated (LoE 5). Discussion: These examination techniques are aimed at identifying (potentially) dangerous conditions, do not pose any immediate hazards to the patient and are not thought to be very time consuming. However, there may be a considerable inter-examiner variation which has never been elucidated. 10,11,13,14 Diagnosis of pneumothorax At present, there are no methods available to identify or exclude pneumothorax in the pre-clinical setting definitively. It can only be ruled out by computed tomography. However, clinical examination may diagnose clinically relevant pneumothorax with some probability. Auscultation. Table 2 gives a synopsis of the data with respect to auscultation. The specificity for pneumothorax of ipsi-lateral diminished breath sound has been shown to range between 93 and

4 14 C. Waydhas, S. Sauerland Table 2 Diagnostic accuracy of a pathological finding during auscultation with respect to the presence of pneumo- /hematothorax Author (year) Patients Sensitivity (%) Specificity (%) Hirshberg et al. (1988) 13 Penetrating trauma (n = 51) Wormald et al. (1989) 7 Penetrating trauma (n = 200) Thomson et al. (1990) 14 Penetrating trauma (n = 102) Chen et al. (1997) 10 Penetrating trauma (n = 118) Chen et al. (1998) 15 Mainly blunt trauma (n = 148) Bokhari et al. (2002) 16 Blunt trauma (n = 523) Bokhari et al. (2002) 16 Penetrating trauma (n = 153) %. The positive predictive value, i.e. that a pneumothorax is actually present when ipsi-lateral diminished breath sounds are found, is reported in 86 to 97% (LoE 1). 14,15 Pneumothoraces not identified by auscultation had a mean volume of 378 ml (maximum 800 ml) (LoE 3). 10,13 Thus, major life-threatening pneumothoraces have not been missed in these studies. In another prospective study auscultation has been shown to be the most reliable clinical technique to detect pneumothorax in comparison to pain or increased respiratory rate (LoE 2). 16 False positive findings can be encountered with tracheal tube dislocation, ruptured diaphragm or ventilation disturbances in at least 4.5% of cases (LoE 4). 17 Conversely, the combination of normal findings during auscultation and palpation and normal breathing almost ruled out pneumo- or haemathorax (LoE 2). 16 Discussion: These data indicate that large and acutely relevant pneumothoraces can be identified with good reliability, provided that the tracheal tube (if present) is located correctly. The conclusions of these studies might be limited by fact that they were done in emergency departments and not at the scene itself. However, circumstances (noise level, disquiet) may be similar in both settings. In special cases a bilateral pneumothorax can be present resulting in atypical findings (LoE 5). Information how to differentiate between pneumo- and haemothorax is not available. It might be speculated that percussion may be of help but its clinical importance remains unclear (LoE 5). Shortness of breath. Although shortness of breath and increased respiratory rate may be difficult to evaluate in trauma patients with a depressed level of consciousness it has been shown in some studies that normal respiration (10 20 breaths/min) rules out significant pneumothorax after trauma (good specificity: %) (LoE 2) 7,16,18 while shortness of breath and increased respiratory rate have a low sensitivity for intra-pleural air ( %). Thoracic pain. In the conscious patient the presence of thoracic pain can be evaluated. In addition palpation and compression of the chest may elucidate pain. Only one study looked at this sign in particular. 16 They reported a 57.1 and 25% sensitivity and a 78.6 and 91.5% specificity of pain in patients with blunt and penetrating trauma, respectively (LoE 2). Synopsis of auscultation, respiratory rate and shortness of breath. The diagnostic accuracy to identify or rule out pneumothorax correctly can be improved by combining these three signs (Table 3). Other signs. Subcutaneous emphysema is thought to be a useful indicator of pneumothorax by many emergency physicians. However, good scientific data are not available and, particularly, specificity and positive predictive values are not known. Sensitivity is estimated to be as low as 12 25% in some observations (LoE 4). 19,20 In a 30-year-old study of critically ill ventilated patients 21 a 100% sensitivity of subcutaneous emphysema for tension pneumothorax was reported, but these data may not be applicable to acutely injured patients in the pre-hospital setting. Unstable thoracic wall and crepitation may indicate thoracic injury but have not been evaluated with respect to their correlation with the presence of pneumothorax. The suspicion of pneumothorax may be triggered by low oxygen saturation on pulse oximetry and low arterial pressure. Di Bartolomeo et al. 12 found lower oxygen saturation (87% versus 94%) and a lower systolic blood pressure (103 mmhg versus 112 mmhg) in patients with pneumothorax. However, no sensitivity or specificity data were given (LoE 3). Progression of pneumothorax. The progression of an initially small pneumothorax to a symptomatic or even tension pneumothorax is of some concern in the pre-clinical setting, particularly during air rescue. It can be assumed that there may be a wide variety of courses ranging from stable pneumothorax to fast progression to tension pneumothorax. There are only few data available from several

5 Pre-hospital pleural decompression and chest tube placement 15 Table 3 Statistical likelihood of the presence of a clinically significant pneumo- or haematothorax with different signs of thoracic pain, shortness of breath and one-sided diminished breath sounds in patients with blunt trauma (based on an assumed pre-test prevalence of 10% and independence of the different findings among each other) Thoracic pain (sensitivity 57%, specificity 79%) Shortness of breath (sensitivity 43%, specificity 98%) Auscultation (sensitivity 90%, specificity 98%) > <1 Likelihood for pneumoor haematothorax (%) smaller studies under different clinical situations that observed the incidence and rate of progression of pneumothoraces. In one retrospective series there was progression to large intra-pleural retention of air requiring chest tube insertion in 2 of 13 cases with occult pneumothorax on days 2 and 3 after initial diagnosis (LoE 4). 22 Progressive pneumothorax was observed in 8 of 21 patients of a prospective randomised study with an observational strategy of occult pneumothorax, 3 of those presenting as tension pneumothorax (LoE 2). All those subjects were on mechanical ventilation. 23 In this study the tension pneumothorax was diagnosed in the operating theatre (n = 1), postoperatively in the ICU (n = 1) and during prolonged resuscitation (n = 1). The exact time lag between diagnosis of the occult pneumothorax and tension pneumothorax was not reported, however. A time span of at least min can be assumed from the circumstances reported. In another prospectively randomised study the progression of diagnosed occult pneumothorax was similar in patients treated by observation (12.5%) or with chest tube insertion (21%) (LoE 2). 24 No data on the time course of progression were given in this study. In a series of 44 newborn, mostly intubated infants the delay between the suspected onset of pneumothorax and clinical diagnosis averaged at 127 min with a range between 45 and 660 min (LoE 4) 25 indicating the speed of progression to a clinically relevant size in this special group of patients. Discussion: In three studies (LoE 4) chest tube insertion was recommended for a pneumothorax size of more than 5 80 ml ( 400 ml). 23,24,26 Since pleural air collections above this size can usually be detected clinically by auscultation (see above) it can be speculated that pneumothoraces with normal breath sounds have some similarity with the occult pneumothoraces cited in the studies about Recommendations: A pneumo- or haemathorax can be assumed when ipsi-lateral breath sounds are diminished or absent during auscultation, provided a correct position of the endotracheal tube was ascertained (grade A recommendation). Normal breath sounds, particularly in conjunction with a normal respiratory rate and no thoracic pain, rule out a significant but not a small pneumothorax (grade A recommendation). The potential progression of a small to a large pneumothorax has to be accounted for (grade B recommendation). Subcutaneous emphysema may indicate the presence of pneumothorax, as well as unstable thoracic wall, crepitation, shortness of breath or increased airway pressure in ventilated patients, although these signs are unreliable (grade C recommendation). pneumothorax progression. Some experts assume that the risk of pneumothorax progression to tension pneumothorax is higher in ventilated patients (LoE 5), 27 but this has never been quantified. Diagnosis of tension pneumothorax Good scientific data are not available that describe the diagnostic accuracy of any clinical sign to identify tension pneumothorax. Virtually all information is based on case reports, animal experiments and expert opinion. Discussion: There is no clear definition of what tension pneumothorax exactly is. Definitions range from severe clinical manifestations to a hiss of air on thoracic needle decompression, mediastinal shift on the chest X-ray, increased ipsi-lateral intrapleural pressure or haemodynamic compromise in conjunction with other signs. 28 For obvious

6 16 C. Waydhas, S. Sauerland reasons ad hoc diagnosis in the pre-hospital setting can only be made on clinical signs, including haemodynamics. According to widespread expert opinion loss of breath sounds on the injured side, provided the tracheal tube is correctly placed, plus signs of life-threatening haemodynamic and respiratory compromise indicate the presence of tension pneumothorax. Cyanosis, shortness of breath, increased respiratory rate, tracheal deviation to the contralateral side, decrease of arterial oxygen saturation, hypomobility and hyperexpansion on the ipsilateral side are among the respiratory symptoms that may occur, whereas distended jugular veins, tachycardia, a fall in blood pressure and circulatory arrest may represent the circulatory sequelae. However, many of these signs depend on subtle clinical judgement and none have been studied systematically. Data are scarce for trauma patients and much of the information is gathered from tension pneumothorax from various causes in the hospital and the intensive care setting. 29 Experimental studies indicate that, in the awake patient, respiratory dysfunction and arrest due to hypoxia in the respiratory centre precede the circulatory arrest, and that hypotension appears to be a late sign with circulatory arrest being the last occurrence in the series of events (LoE 5). 27,30 These experimental findings have recently been confirmed in a case of an accidentally created tension pneumothorax in a patient, who became dyspnoeic, cyanotic, unconsciousness and developed respiratory arrest while carotid pulse was palpable throughout. 31 After decompression of the increased intra-pleural pressure the condition quickly resolved. Tension pneumothorax was present in chest X-ray examination (shift of mediastinum to the contra lateral side) without signs of circulatory depression during clinical examination in another case report (LoE 4). 32 In this patient the circulation remained stable during the 30 min between clinical diagnosis and chest tube insertion. In a further case report marked cyanosis, increased respiratory and heart rate and depression of consciousness (GCS of 10) were the clinical signs while the other symptoms and findings listed above were missing. However, ipsi-lateral hyperexpansion and hypomobility was noted by careful inspection. This course of pathophysiological events in the awake patient was confirmed in a recent review by Leigh-Smith and Harris. 28 They suggested respiratory distress and tachycardia to be the most common findings in the awake patient. However, they showed that in ventilated patients with tension pneumothorax the onset of symptoms is quicker and hypotension and respiratory symptoms may be present at the same time in many Recommendations: Although there is no unambiguous consent, many experts believe that the combination of an ipsi-lateral decrease of breathing sounds (provided that the tracheal tube is correctly placed) in combination with typical respiratory and circulatory signs suggest tension pneumothorax. In the spontaneously breathing patient increased respiratory rate, respiratory distress, a decrease in oxygen saturation and tachycardia prevail while in the ventilated patient increased ventilatory pressure and hypotension will be found additionally in an earlier phase of the condition. Ipsi-lateral hyperexpansion and hypomobility may help to lateralise pneumothorax as will visible signs of injury, while many other signs are inconsistent (grade C recommendation). cases. In ventilated patients an elevated or increasing airway pressure may be an additional indicator of tension pneumothorax found in up to 20% of subjects with pneumothorax (LoE 4). 9,11 Since the development of tension pneumothorax is a progressive event, the time course of symptoms and their severity should be accounted for. Indication for decompression of the pleural space There are no high quality studies available with respect to the indication for pleural space decompression in the pre-clinical environment. All recommendations are based on case series, single cases and expert opinion. Tension pneumothorax Discussion: Tension pneumothorax represents an acutely life-threatening situation that usually results in death, unless treated. If there are signs of impaired respiratory and circulatory function, death may supervene within minutes. Many experts feel that in the latter situation immediate decompression is necessary and that transport without treatment to even a hospital close by represents an unwarranted delay. In an autopsy study of 3500 cadavers there was an incidence of 39 tension pneumothoraces (1.1%), approximately half of them unrecognised before death. Although it may be argued that immediate treatment of tension pneumothorax, should be compulsory with the highest level of evidence (LoE 1) (due to all-or-nothing evidence), the potential for false diagnosis in the pre-hospital setting makes such a recommendation

7 Pre-hospital pleural decompression and chest tube placement 17 Recommendations: A clinically suspected tension pneumothorax should be decompressed at the scene (grade C recommendation). Recommendations: A clinically diagnosed pneumothorax can be decompressed in ventilated patients. Non-ventilated patients can be transported with close clinical monitoring. If in the latter case close monitoring is not possible (e.g. helicopter transport) decompression can be considered in selected patients (grade C recommendation). less strong. Furthermore, there is a case report of a patient surviving symptomatic tension haemothorax that has been treated by decompression after a period of 18 h after onset (LoE 5) 33 indicating that the progression of clinical deterioration may be delayed. Pneumothorax Discussion: As has been described above a large pneumothorax may be assumed, if there are diminished or absent breath sounds. Generally speaking, a large traumatic pneumothorax should be decompressed and evacuated. Whether this should be done at the scene or during transport to a hospital is a matter of debate, depending on the speed of progression to tension pneumothorax. The dynamics of this progression appears to be highly variable and little data are available to make accurate predictions. There are some concerns that the risk of progression to tension pneumothorax is increased in patients that are mechanically ventilated as compared to spontaneously breathing subjects. In a series of 54 traumatic pneumothoraces 29 have been initially treated without drainage. These patients were mostly spontaneous ventilating and presented with isolated chest injury. In only two cases was a chest tube inserted during the later course because of radiological progression of the pneumothorax within 6 h after admission. 34 Thus, pre-hospital decompression of suspected simple pneumothorax in the spontaneously breathing patient appears not to be generally indicated. However, close clinical monitoring is necessary to detect deterioration of the patient. If monitoring cannot be maintained reliably, e.g. during helicopter transport, some risk of progression from simple to tension pneumothorax cannot be ruled out but appears rather low. Recommendations: Chest tube placement in patients without clinical signs of pneumothorax but suspected chest injury appears not to be indicated in the pre-clinical situation. Only in selected ventilated patients with long helicopter transport times and restricted clinical monitoring should chest tube placement be considered (grade C recommendation). Chest injury with normal breath sounds Discussion: Some clinicians advocate decompression of the pleural space when respiratory function is severely depressed despite apparently normal findings during auscultation. The association of suspected or proven chest injury with pneumothorax is unclear. Therefore, no evidence-based recommendation can be made with respect to pre-hospital decompression of the pleural space. However, some estimations of the risk of pneumothorax can be made. The presence of significant chest injury indicates a risk of pneumothorax in a range of 10 50%. This would imply that a chest tube or other type of decompression and evacuation of the pleural space would be required in every second to every tenth patient. On the other hand, chest tube placement would represent an unnecessary intervention in at least every second subject up to 9 of 10 subjects. This number quite well corresponds with the reports that pre-clinical decompression leads to an release of air in only 32 50% of cases 9,35 and that the indication for chest tube insertion was uncertain in 9 25% of patients, because no pneumothorax or chest injury was present. 35,36 When extrapolating these data it has to be kept in mind that in those studies the radiological diagnosis of pneumothorax has not been correlated with the clinical findings and it has to be assumed that some of those would have been suspected clinically. Thus, the incidence of pneumothorax in those patients without clinical signs of pneumothorax can be assumed to be even lower. 22 Moreover, occult pneumothoraces have been included in some of these studies, which have been detected only some time after hospital admission with computed tomography but not standard chest X-ray. 37,38 Therefore, the portion of clinically relevant preclinical pneumothoraces that are suspected only because chest injury is present is reduced even more. Methods to decompress the pleural space The initial goal of therapy is to decompress the increased intra-pleural pressure of tension pneu-

8 18 C. Waydhas, S. Sauerland mothorax. A secondary aim is to prevent a progression of simple pneumothorax to tension pneumothorax. The complete and permanent evacuation of air from the pleural space, however, is of minor concern for the pre-hospital treatment. Since there are no studies available that directly compare the different methods (needle decompression, surgical incision alone, chest tube placement) no definitive advantages can be found for one or the other method. All data are based on mainly retrospective case series that indicate that decompression of the pleural space can be achieved with any of these methods. Because of the low level of evidence with respect to the choice of methods a comparison can only be made accounting for practicability, complication rate and the competence of the emergency ambulance physician, paramedic or nurse. We found only one study comparing different providers with respect to complication rates. In a US study it has been shown that the complication rate of chest tube placement was significantly different whether it was done by surgeons or emergency physicians (LoE 2). 39 Whether these findings can be extrapolated to other institutions or countries is not known, however. Needle decompression: efficiency and complications Needle decompression has been studied in several case series. In a clinical study by Barton et al. air was released through the needle in 47% of cases. In 32% of patients with needle decompression an improvement of vital signs was observed (LoE 2). 9 A similar investigation (LoE 4) 40 reported the release of air in 32% of 89 needle thoracostomies with no difference whether the patient was pulseless or had a pulse. However, a release of air was observed more frequently in intubated than in non-intubated patients (34.9% versus 25.0%). The overall response rate of 60% remains unexplained since it is unclear how needle decompression can improve vital or clinical signs without the release of air from the pleural cavity. In the prospective series of another study pre-hospital needle decompression resulted in an improvement of vital signs or a reduction of dyspnoea in only 12% of subjects (LoE 2). 41 In contrast to these studies in favour of needle decompression in a prospective series of 14 patients with pre-hospital needle decompression one patient still had persistent tension pneumothorax and two presented with persistent simple pneumothorax, while there was no indication of an initial pneumothorax in retrospect in eight cases and two occult pneumothoraces were found. There Recommendations: Needle decompression often appears to be an effective, easy to use, and relatively save method to treat (tension) pneumothorax. Because of insufficient decompression additional chest tube insertion may be required in a significant number of subjects (grade C recommendation). was only one tension pneumothorax that was successfully treated. Another five cases could not be validated because they died in the emergency room before a precise diagnosis could be made (LoE 4). 42 In Barton s study (LoE 2) 9 40% of patients (32 of 123 patients) required the additional insertion of a chest tube because of poor efficiency of the needle decompression. Similar data from another group indicated the need for pre-clinical chest tube insertion after needle decompression in 67% of subjects (LoE 4) 43 which is well in line with the rate of additional tube thoracostomies of 53% in the study of Davis et al. 40 (LoE 4). They found a release of air after chest tube insertion in 33% of subjects when there had been a favourable response to needle thoracostomy before and in only 15% if needle decompression had not resulted in an improvement. 40 Needle decompression of suspected pneumothorax was not possible because of insufficient needle length in 4.1% of patients. In 2.4% of cases a secondary dislocation of the needle was noted, while the puncture itself was deemed difficult in 4.1% of interventions. 9 Eckstein and Suyehara 41 in their series reported unsuccessful intervention in 2% because of insufficient needle length and no indication for the procedure with consecutive iatrogenic pneumothorax in 2% of cases, respectively (LoE 2). Several case reports indicated the failure of needle decompression to treat tension pneumothorax (LoE 4) with the necessity for thoracotomy. 29 No organ injuries have been reported in one study (LoE 2). 9 Eckstein and Suyehara also did not observe procedure-related infection or vessel injury, 41 whereas in another study there was one lung injury in the patients with needle thoracostomy (4.2%). 40 In a case report a perforation of the pulmonary artery with consequent cardiac tamponade was reported after needle decompression. It is important to note that this patient had absent breath sounds due to undetected intubation of the right mainstem bronchus. 48 Furthermore, three cases of severe haemorrhage requiring thoracotomy were reported by one group. 49

9 Pre-hospital pleural decompression and chest tube placement 19 Table 4 Complication rates of chest tubes inserted in the emergency department (in-hospital) vs. on the scene (pre-hospital) Type of complication Pre-hospital chest tubes only In-hospital chest tubes only Subcutaneous malposition 2.53% ( %) N = 790, %* ( %) N = 772, 6 studies 9,17,19,20,35,51 53,60 studies 55,60, Intra-pulmonary malposition 1.37% ( %) N = 657, % ( %) N = 1275, 7 studies 9,17,19,20,35,51,52 studies 55,97, Intra-abdominal malposition 0.87% ( %) N = 690, % ( %) N = 956, 5 studies 9,17,19,20,35,51 53 studies 55,97,102,104,105 Pleural empyema 0.55% ( %) N = 550, %* ( %) N = 8102, 13 studies 9,35,51,52,60 studies 39,54,60,97, Data are given as mean (CI in parenthesis) after simple pooling from studies in which the respective complication was reported. Chi-square-test was applied to test for differences. n.s., not significant; *p < 0.05 (pre-hospital vs. in-hospital). Recommendations: Surgical incision and decompression of the pleural space without insertion of a chest tube appears to be an effective method to treat tension pneumothorax. Safety and complication rates cannot be determined (grade C recommendation). Surgical decompression: efficiency and complications From clinical experience it is known, that during incision of the pleura while preparing the channel for chest tube insertion there can be a release of air from tension pneumothorax with immediate relief of circulatory and respiratory dysfunction. In a case series, this technique alone, without consecutive chest tube placement, was studied in 45 patients at the scene (LoE 4). 50 It was shown that surgical decompression was effective in terms of the release of air, improvement of chest wall excursions and the return of breath sounds in all patients. What remains unresolved from this single study evaluating surgical decompression is the frequency and time delay of recurrent tension pneumothorax due to the fact that the incision might close again spontaneously. Close monitoring appears to be warranted after the procedure (LoE 5). Complication rates are unknown. Chest tube: efficacy and complications The success rate (decompression and evacuation of air from the pleural space) of pre-hospital chest tubes is reported to range between 79 and 95% (LoE 4). 35,51 53 It has been the definitive treatment of pneumothorax in these cases with no other intervention required. In contrast, the failure rate of chest tubes (false position, insufficient drainage) ranges from 5.4 to 21% (mean 11.2%) requiring another chest tube to be inserted (LoE 4). 35,39,51 56 The failure rate is composed of retained pneumothorax and haemothorax in equal parts. Some single cases of persistent tension pneumothorax despite pre-clinical chest tube insertion are reported (LoE 4). 51,57,58 Pooled complication rates of chest tubes are shown in Table 4 (LoE 5). However, there are only two studies that directly compare the complication rate of pre-hospital and emergency department chest tube insertions in one institution (LoE 2). 59,60 They observed a similar rate of infection complications of 9.4 and 11.7% 59 for pre-hospital and emergency department chest tube insertion, with 0 and 1.2% malpositions, respectively. The duration of drainage was similar in both groups (4.1 and 4.3 days). There appeared to be no differences between chest tubes inserted in the emergency room (in the hospital) or at the scene. Chest tubes can be inserted either in the midaxillary line or the mid-clavicular line. For the puncture in the mid-axillary line some rare complications are reported in case reports (LoE 4): laceration of inter costal arteries, 61 perforation of the lung, 62 perforation of the right atrium, perforation of the right 66 and left ventricle, 67 obstruction of the subclavian artery from pressure of the tip of the tube, 68 Horner s syndrome from pressure of an apical tube on the stellate ganglion, 57,69 intra-abdominal placement, 70 intra hepatic placement, 19 laceration of the subclavian vein and perforation of the inferior vena cava. 71 After insertion of chest tubes in the mid-clavicular line an arterio-venous fistula, 72 a myocardial perforation 73 and perforation of the right atrium 64 have been reported. Furthermore, perforation of the oesophagus, of the mediastinum with contra lateral pneumothorax, injury to the phrenic nerve and others complications are known of. What role the qualification and experience of the medical personnel (emergency nurse, paramedic, emergency physician, anaesthesiologist, surgeon,

10 20 C. Waydhas, S. Sauerland Recommendations: Chest tube insertion is considered a suitable and effective method to decompress tension pneumothorax. It has a potential for complications, however. It appears to be particularly indicated when other measures such as needle decompression are not successful (grade C recommendation). Recommendations: Tension pneumothorax may be decompressed successfully by needle aspiration or surgical decompression alone or in conjunction with chest tube insertion, provided the correct technique (grade B recommendation). In cases with insufficient success after needle decompression, surgical decompression or chest tube placement may be helpful. Chest tube insertion appears to be the most effective method with respect to definitive drainage of the pleural space (grade C recommendation). etc.) may play is not well known. However, pleural decompression is a procedure not frequently performed. About half of a group of experienced emergency physicians reported not to have used chest tubes in the pre-hospital setting at all, while the other half has inserted a thoracostomy tube four times (mean) during an average period of 5.9 years. 74 Needle decompression versus chest tube Needle decompression required approximately 5 min less scene time compared to chest tube insertion in two studies (LoE 2). 9,40 While the release of air was noted in 47% of cases after needle decompression, this was the case in 53.7% with chest tubes (LoE 2). 9 In a randomised study in patients with spontaneous pneumothorax (traumatic causes have been excluded in this investigation) (LoE 4) the success rate of chest tube insertion amounted to 93% which was significantly higher than after simple needle aspiration (68.5%). 4 Another prospectively randomised study revealed similar results with a success rate of 84.9 and 59.3% after chest tube or needle aspiration, respectively (LoE 4). 5 33% of the subjects with needle aspiration required another puncture or the placement of a chest tube. To what degree these observations in the treatment of spontaneous pneumothorax can be translated to the management of traumatic pneumothorax remains open. Recommendations: Both the 4th 6th intercostal space in the mid-axillary line or the 3rd intercostal space in the mid-clavicular line are suitable for needle decompression or chest tube insertion (grade C recommendation). Technical considerations Puncture site Generally speaking, the 2nd 3rd intercostal space in the medial clavicular line or the 4th 6th intercostal space in the ventral to mid-axillary line are recommended for puncture of the pleural space. There are no communications available that have compared success and complications rates with respect to using either site. Discussion: As with needle decompression some authors recommend the 2nd 3rd intercostal space in the medial clavicular line (LoE 5) 9,11,41,42 and others the 5th intercostal space in the mid-axillary line (LoE 5). 8,75 It has been argued that the chest wall thickness is greater in the ventral location than in the mid-axillary line. This, however, has not been confirmed in a study in cadavers where the mean chest wall thickness was found to be 3.0 cm in the medial clavicular line and 3.2 cm in the midaxillary line, respectively (LoE 5). 76 Other reasons that support the ventral puncture site are the proposed higher probability to find trapped air in an apical location and the decreased risk of lung lacerations due to adhesions. These arguments have, to our knowledge, not been validated by clinical data. However, in one communication three cases of severe haemorrhage from punctures in the 2nd intercostal space have been reported. 49 A similar inconsistency of recommendations can be found for the most suitable site for chest tube insertion. The 4th 6th intercostal space in the midaxillary line is supported (LoE 5) 11,77,78 as well as the 2nd 3rd intercostal space in the mid-clavicular line. Usually, it is recommended not to perform the incision below the level of the nipple of the breast because the risk of intra-abdominal malposition or intra-abdominal organ injury might be increased. It is of note that by level the site for perforating the intercostal space is meant and not the level of the skin incision, which may be one space lower. For both puncture sites serious complications have been reported in case reports (see above). In one prospective study there was no influence on the success of drainage after pneumo- or haemothorax from penetrating trauma whether the chest tube was inserted at the 2nd or 8th intercostal space or in the mid-clavicular or mid-axillary line (LoE 4). 79

11 Pre-hospital pleural decompression and chest tube placement 21 Needle and tube size Needle decompression. The average thickness of the chest wall in 54 patients by using ultrasound was found to be 3.2 ± 1.5 cm (LoE 2). 44 They observed that in 57% of patients the skin-to-pleura distance was more than 3 cm and that it was more than 4.5 cm in 4% of subjects. They concluded that a needle length of at least 4.5 cm is required to be able to reach the pleural space in the majority of patients. Even this needle length is too short in some situations (LoE 4). 80 In a more recent study measuring chest wall thickness in chest trauma patients by using computed tomography Givens et al. 81 (LoE 4) reported an average thickness of 4.16 and 4.90 cm in the mid-clavicular line in men and women, respectively. In their study, about a quarter of patients had a chest wall thickness of more than 5 cm. In a similar study of 30 thoracic CT-scans a mean chest wall thickness in the mid-clavicular line of 4.2 cm was reported. Thirty-three percent of subjects had a thickness of more than 5 cm and 10% of more than 6 cm, respectively. 82 Both studies gave no data with respect to the chest wall thickness in the mid-axillary line, unfortunately. No data are available with respect to the diameter of the lumen to allow for sufficient air flow to release increased pressure. Surgical decompression. To decompress pneumothorax, theoretically, a relatively small diameter drainage tube should be sufficient. In nontraumatic pneumothorax catheter sizes of 8 14 Fr were adequate in 75 87% of patients (LoE 4). 83,84 In one study with traumatic pneumothorax an 8 Fr drainage was sufficient for treatment in 75% of cases, while in the remaining 25% the insertion of a wider chest tube was necessary (LoE 3). 85 In a recent case report there was progression to tension pneumothorax in a ventilated patient with pneumothorax due to a ruptured emphysematic bulla despite a small-bore chest tube in place (LoE 4). 86 Since at least 30% of posttraumatic pneumothoraces are combined with significant amounts of blood within the pleural space there is the possibility of obstruction of narrow-lumen drains. Therefore, many experts recommend large bore chest tubes (28 36 Fr) in adults (LoE 5). 77,78,87,88 Drainage systems There are no sound data available as to the use or choice of drainage systems in traumatic pneumothorax. No lock (open drain). For theoretical reasons a chest tube in a ventilated patient could remain open to the atmosphere without compromising ventilation. However, due to the emission of blood from the drainage opening there may be an increased risk Recommendations: A needle length of at least 4.5 cm should be used for needle decompression (grade B recommendation). However, a significant number of patients my have a chest wall thickness of more than this length, depending of nutritional status or country of origin. Whether the use of a longer needle may have a higher rate of success and with the same rate of complications is not known and can therefore not be recommended. Chest tubes of Fr are recommended (grade C recommendation). of disease transmission from the blood to the medical personnel and soiling of equipment and transport vehicles. On the other hand the risk of obstruction and recurrent (tension) pneumothorax appears rather low. In spontaneously breathing patients, however, the risk of total collapse of the ipsi-lateral lung is possible and some type of valve appears necessary. Heimlich-valve. The Heimlich-valve is one of the commercially available valves. It has been developed for the relief of spontaneous pneumothorax. 89 Despite the lack of significant admixtures of blood there was one failure (out of 18 cases in this series) (LoE 4) due to occlusion of the valve mechanism. In a retrospective comparison of 19 patients treated with Heimlich-valves and 57 subjects treated with standard drainage systems with more than of third suffering from traumatic pneumothorax Niemi et al. 90 found a shorter duration of drainage time and hospitalisation. However, subjects with haemothorax were excluded and four patients with Heimlich-valve had to be converted to standard thoracic drainage (LoE 2). Therefore, the data of this study may not be quite applicable to the pre-hospital trauma setting. Further case reports document the potential for failure of the Heimlich-valve even with the recurrence of tension pneumothorax despite initially successful decompression (LoE 4). 91,92 During routine use in the Falklands War frequent obliteration from coagulated blood was observed, requiring replacement of the Heimlich-valve. However, the magnitude of problem was not exactly quantified in this publication (LoE 4). 93 In an experimental study (LoE 5) it was shown that two of eight Heimlich-valves malfunctioned. This occurred in seven of eight samples if they were used after the expiry date. 92 Thus, incorrect function of the Heimlich-valve may be caused by material fatigue, coagulated blood or both resulting in a potential for recurrent (tension) pneumothorax. Furthermore, the use of a

12 22 C. Waydhas, S. Sauerland Recommendations: To seal the open end of a chest tube in the spontaneously breathing patient some kind of valve may be helpful (grade C recommendation). No recommendation can be given for the ventilated patient. Heimlich-valve without some kind of collecting system also bears the risk of soiling and disease transmission. Closed bag or collecting chamber systems. By collecting the pleural secretions in some kind of bag or chamber reduces the risk of soiling and disease transmission. However, if the air leak is large enough pressure might quickly develop within the collecting system potentially resulting in recurrent (tension) pneumothorax. Under hospital conditions collection of pleural secretions and air in (commercially available) twoor three-bottle systems is common practice. They function well and have good safety for patients and medical personnel. For the pre-hospital use they have some inherent problems, particularly the risk of falling over during patient transport. Tilting of the chamber system could lead to uncontrolled shifting of fluids and might compromise function and safety. One commercially available drainage system with a backstroke valve and a bag with a vent has been shown to be equivalent to a multichamber system with water seal for drainage in patients after thoracotomy in a randomised study (LoE 2). 94 No occlusions were reported although the drains produced bloody secretions in the postoperative period. There are no experiences reported of its use for traumatic haemo- or pneumothorax. The use of a simple bag without a valve (e.g. colostomy bag) (LoE 4) 95 has never been evaluated for the use in trauma patients and appears not to be a choice for the drainage of traumatic pneumothorax. Insertion of the needle or chest tube Needle decompression. The best technique of needle decompression has not been validated in controlled trials; any recommendations are based on expert opinion and case series. Discussion: It is recommended to perform the puncture by introducing an over-the-needle catheter with a syringe attached and to advance it with aspiration until the pleural space is reached. 11 After successful puncture of the pleural space some authors suggest leaving the metal needle in place to prevent the flexible catheter snapping off (LoE Recommendations: Puncture for needle decompression should be done by introducing an over-the-needle catheter with a syringe attached until the pleural space is reached. Surgical decompression and chest tube insertion should be achieved by blunt dissection with curved scissors. No trocar should be used. 5) 42,96 while others recommend removing the needle and leaving only the plastic catheter in place (LoE 5). 41 Surgical decompression/chest tube insertion. The best technique of chest tube insertion has not been validated in controlled trials; any recommendations are based on expert opinion and case series. Discussion: Most authorities consent on a standardised procedure: a sterile technique is employed. After skin disinfection local anaesthesia should be used in the conscious patient including anaesthesia of the parietal pleura. A transverse incision (4 5 cm) is made with a knife over the rib just below the designated intercostal space or one rib lower. In women a skin incision in the submammary fold can be used for cosmetic reasons. The subcutaneous and intercostal tissue is bluntly dissected over the upper border of the rib by using curved scissors or a blunt clamp. The parietal pleura may be dissected bluntly or incised with the scissors. Then one finger (sterile glove) is inserted into the pleural cavity to verify correct access and feel for adhesions (LoE 5). 50,77,78,87,97 99 A subcutaneous tunnel is not thought to be necessary by all experts (LoE 5). 99 A trocar for blunt dissection must not be used. Major complications have been reported such as perforation of the right atrium in a patient with kyphoscoliosis 64 or of the lung. 62 There are no published direct comparison studies between the trocar and non-trocar techniques. However, reported complications rates are higher in studies using the trocar technique compared to studies using blunt surgical dissection (11.0% versus 1.6%). Some authors recommend a pause in expiration at the moment of pleural incision in ventilated patients to minimise the risk of parenchymal lung injury (LoE 5). 62,100,101 The chest tube is then advanced through the prepared canal either using a finger to direct the catheter tip or to guide it by means of a clamp that holds the tip of the chest tube. Alternatively, the chest tube may be guided by a trocar (only to guide, not to dissect). In this case the sharp tip of the trocar must be well inside the tube (LoE 5). 78