Introduction
Physicians providing EMS medical oversight and those providing direct patient care in the prehospital environment must possess a significant level of expertise in the use of non-invasive and invasive procedures for the prehospital stabilization of trauma patients. The nature of the care and the procedures that are appropriate for different levels of providers is based on the education, training, and legal scope of practice of the providers in the EMS system. An EMS physician must be skilled in these procedures and maintain active educational programs and continuous quality improvement activities to insure these procedures are being performed correctly, and under the correct circumstances. In some cases, it may be appropriate that only an EMS physician perform a procedure, either due to special circumstances or due to the provider’s ability and/or scope. Appropriate hands-on and didactic training, as well as verification of procedural proficiency, should occur prior to implementing any procedural skill.
Needle thoracostomy
The placement of a needle to relieve tension pneumothorax is often used in ground EMS systems. Some air medical (and critical care) services have also authorized the placement of a formal tube thoracostomy by their crews. The placement of a needle into the pleural space can produce dramatic results in a patient suffering from a tension pneumothorax.
Indication
This procedure should be considered in any patient who suffers from rapid cardiopulmonary decompensation in an appropriate clinical setting. Although tracheal deviation and decreased breath sounds are commonly accepted as signs of a tension pneumothorax, they may not always be present and may not be appreciated in some prehospital environments [1]. Providers should be encouraged to perform this procedure in any blunt chest trauma patient who has a precipitously decreasing course, especially if there is a history of chronic obstructive pulmonary disease or asthma. Trauma patients with obvious subcutaneous emphysema can benefit from the early application of this technique. Eckstein and Suyehara reviewed their experience in a series of over 6,000 trauma patients [2]. Their conclusion, based on the 108 patients in this series who received needle decompression, was that this was a potentially life-saving intervention, with a low complication rate.
If the catheter is placed into the lung parenchyma, the puncture will be small and should heal rapidly. The resultant pneumothorax is an open one, and therefore the patient should suffer little further compromise. If the patient is intubated, the thoracostomy catheter may be placed and left open to the air. If the patient is spontaneously breathing, a one-way valve must be created to prevent reentry of air during inspiration. One-way valves, such as the Heimlich valve, are available with tubing that will connect with a standard venous catheter. Condoms may be used by puncturing the condom with the catheter and then unrolling it after the catheter has been placed in the patient. Surgical gloves have been used, but when compared with condoms, they may produce unacceptable air leakage. Some services will use an aquarium air pump check valve, but despite anecdotal success, there do not appear to be any available scientific data evaluating their use for this purpose. Other devices, such as the McSwain Dart, have also been used for chest decompression, but they confer no demonstrated advantage over a venous catheter.
For most EMS systems, needle thoracostomy is the safest, most rapid, and most effective way of providing pleural decompression.
Technique
Locate the second intercostal space, in the midclavicular line on the anterior chest wall of the affected side. An alternative site is the midaxillary line at the level of the nipple, similar to the usual chest tube site. Apply best possible sterile skin preparation with sterile prep. Load the pneumothorax catheter onto the tip of the 10 mL syringe. Direct the catheter perpendicular to the skin, keeping in mind that ideal placement is over the top of the rib and not into the inferior portion of the superior rib which risks damaging the neurovascular bundle. Enter the skin and, while gently withdrawing on the plunger, advance the catheter until air moves freely into the syringe (with or without blood return). The plastic catheter should then be advanced off the needle and into the chest. The syringe (frequently a larger syringe) may be used in conjunction with a stopcock to aspirate the air from the pneumothorax until resistance is noted on the plunger. A one-way valve may then be connected to the end of the catheter. A definitive thoracostomy tube will need to be placed after acute decompression with needle thoracostomy (typically in the hospital setting or in critical care transport situations).
Complications
The rate of significant complications is thought to be low. It is possible to puncture the subclavian vein and/or artery if the second interspace technique is done improperly and the needle is placed too high on the chest. If the lateral approach is used, abdominal organ injury may result from a needle placed too caudad. Laceration of the internal mammary artery and the risk of infection are two other complications to consider. Care is needed to avoid these complications by providing the best available level of preprocedural cleaning and utilization of landmarks when placing the needle.
Tube thoracostomy
This common surgical procedure, mostly limited in the field to air medical services or military situations, is used to evacuate air or blood from the pleural space. It is particularly useful when transport times are sufficiently long. Once the tube has been secured, one must decide what to do with the free end of the tube. If the patient is intubated the tube may be left open, creating an open pneumothorax. For a patient who is not intubated, a one-way valve must be created to prevent entry of air into the thorax during inspiration. The Heimlich valve, essentially a rubber flapper valve in a tube, is the most practical device for the paramedic. It may be connected to suction if required, and if there is a large amount of drainage, a urinary catheter bag may be attached to collect the drainage.
Indication
The ability to rapidly evacuate a large amount of blood from the trauma patient’s pleural space, converting a tension hemothorax into an open hemothorax, is this technique’s primary advantage. In some cases this may be life-saving but in others, the patient can exsanguinate from the tube, depending on the source of the bleeding. Placement of the formal thoracostomy tube may also be indicated if a large pneumothorax is present and a long transport time is expected. Potential advantages are the lower likelihood of kinking, clotting, and dislodgment of the tube in comparison to the needle technique.
Technique
Abduct and externally rotate the arm on the affected side so that it is up and out of the way. Locate the fifth intercostal space, in the midaxillary line on the chest wall of the affected side. Apply best possible sterile skin preparation with sterile prep. Locally inject the site with anesthetic. Using the #10 blade scalpel, make a 3–4 cm transverse incision onto the fifth rib at the midaxillary line. With a large Kelly clamp, bluntly dissect over the top of the fifth rib into the fourth intercostal space. Some force may be required to enter the pleural space and the operator should feel a definitive pop upon entering the pleural cavity. At this point there may be a rush of air and/or blood. Spread the tips of the Kelly clamp in the pleural cavity to widen access, then turn the clamp 90° and spread again. Insert a gloved finger into the pleural space to verify proper position and to hold the track while guiding the chest tube into place. The Kelly clamp may then be removed at the provider’s discretion. The tube may be inserted directly or facilitated by the use of a Kelly clamp to grasp the tip, through the eye, to help guide the tube. The tube should be inserted along the tract and into the pleural cavity, while directing it posteriorly and superiorly. The tube should slide smoothly without significant resistance and all of the fenestrations must be inside the chest wall to allow for suction.
If the tube will not advance, the operator may attempt to turn the tube; however, if the tube is drawn out of the chest, a new tube should be used on the next attempt to place through the same tract.
Once the tube is in position, secure the chest tube to the chest wall with a silk suture. Petroleum gauze with a single cut halfway across the middle of the gauze can then be placed around the tube. Dry gauze, with the same cut, is then placed over the petroleum gauze and the elastic adhesive tape is used to hold the dry gauze in position. The tube is then bolstered and taped to the chest wall. The end of the tube should then be connected to the chest tube drainage apparatus, or a Heimlich (one-way flutter) valve should be placed on the end.
Complications
The tube should be placed under sterile conditions. However, this may be difficult or impossible based on the potential prehospital environments in which this may be performed. This may lead to empyema, should the patient survive. Placement in the wrong interspace can result in injury to the abdominal organs, the heart, or great vessels, and the use of trocars or Kelly clamps to place the tube may cause injury to the lung parenchyma or other thoracic structures.
Pericardiocentesis
Pericardiocentesis is classically taught as the procedure of choice for treating cardiac tamponade. Its use in the prehospital setting has not been fully investigated. In the patient suffering from pulseless electrical activity (PEA) due to cardiac tamponade, pericardiocentesis may theoretically restore a perfusing rhythm. Medical directors may wish to include pericardiocentesis in a traumatic PEA protocol; however, its use should typically be reserved for patients in whom fluid challenge and needle thoracostomy have not resulted in palpable pulses.
Indication
The indication for this intervention is the presence of life-threatening physiological changes with signs of traumatic cardiac tamponade. The Beck triad (muffled heart sounds, jugular venous distension (JVD), and hypotension) and Kussmaul signs (pulsus paradoxus, a drop of >10 mmHg during inspiration, and paradoxical increase in JVD, as a sign of increased jugulovenous pressure) are indications of cardiac tamponade. Cardiac tamponade is present in up to 90% of penetrating injuries to the heart [3].
Pericardiocentesis is also indicated for resuscitation of a patient with PEA when other causes have been ruled out and the patient remains pulseless. Pericardiocentesis has been reported successful even in cases of cardiac tamponade from blunt trauma [4].
Technique without ECG or ultrasound guidance
Expose the subxiphoid region and prep the area with sterile antiseptic solution. Position an 18 G (either 3.5 or 6 inch) spinal needle so that it will enter the skin directly below or adjacent to the xiphoid process. The needle should be held at a 45° angle to the skin, aiming at the left shoulder (assuming normal anatomy). This technique minimizes the likelihood of injuring other important structures. The needle is advanced, maintaining angle and direction, while withdrawing on the plunger. The operator stops advancing when blood returns. After removal of up to 50 mL of blood, vital signs are reassessed. In cases of acute tamponade, removal of as little as 25–30 mL can lead to immediate improvement [4]. If hemodynamic status does not improve, perform additional aspiration of blood in 25 mL increments until condition improves. The stopcock may be place on the Luer-Lok end of the spinal needle and may be used for subsequent drainage (either through tubing into a bag or into a syringe with aspiration). If the needle is left in place it must be stabilized. If removed, the operator should consider drainage of pericardial blood until little to no blood returns, and then check for reaccumulation prior to removal. A sterile dressing should be placed over the site.
At this point, if equipped, the operator may choose to utilize the Seldinger guidewire technique and place a flexible plastic catheter instead of leaving the metal spinal needle.
Technique with ECG guidance
Prior to initiating the procedure described above, the operator uses an alligator clip jumper cable to bridge from the ECG lead (V1 in the case of 12-leads, lead II for 3-lead) to the proximal metal portion of the spinal needle. The same procedure may be used, and advancement of the needle is now additionally guided by blood returned and the change on the ECG lead to ST elevation on the monitor. The rest of the procedure is the same as above.
Technique with ultrasound guidance
If prehospital ultrasound is available, it may be employed to guide placement of the needle into the pericardium. The operator will identify the point of maximal effusion in order to guide site selection. The site should represent a superficial access to the effusion and will not likely be the subxiphoid site, due to the ability of the ultrasound to visualize both the effusion and the needle during the procedure. Angle and depth will be guided by the ultrasound. The operator should use the probe before (to identify the site) and during the procedure (in order to guide the needle to the effusion), and after initial drainage (to check for reaccumulation). The rest of the procedure is the same as the blind technique above.
Complications
Classically, the use of this technique has been discouraged in the patient with a traumatic tamponade as it may delay the implementation of thoracotomy. Thoracostomy is not usually available in the prehospital setting unless a properly trained and equipped EMS physician is present [5]. Theoretically, the needle could also cause injury to the myocardium or puncture or lacerate a coronary vessel.
Spinal immobilization
The most critical aspects of patient packaging are those interventions designed to protect the spinal cord from further injury. Before the appearance of organized EMS services and paramedic training, motor vehicle crash victims were often extricated and transported without the use of any form of spinal immobilization. These patients were simply pulled from their vehicles or placed on stretchers without any consideration of splinting or spinal stabilization. It was reported that patients presented to the hospital with completed spinal cord injuries [6]. Immobilization has since become one of the most fundamental interventions provided by prehospital providers. Although this process has been accepted for decades, no formal studies have assessed its validity or effectiveness, and it is not without its problems. Changes in automotive design since the institution of spinal immobilization in the 1960s have led some to question the need for universal spinal immobilization of motor vehicle crash victims. Like so many prehospital interventions, this is a difficult procedure to study given the current medicolegal climate.
In light of recent studies exposing the lack of evidence of the effectiveness of cervical collars and long spine boards in the maintenance of spinal alignment, coupled with the detrimental effects of routine immobilization, it is important to carefully consider protocol design and quality assurance processes in order to limit the adverse effects of this now ubiquitous but not evidence-based practice [7–20].
