Читать книгу Emergency Medical Services - Группа авторов - Страница 168

Trauma:

 Blunt

 Penetrating

Medical:

 Acute asthma, especially if cardiac arrest

 Chronic obstructive pulmonary disease or other underlying lung disease

 Decompression‐associated barotrauma

 Marfan syndrome (or marfanoid habitus)

 Thoracic endometriosis (catamenial)

Finger thoracostomy is an additional technique for emergent chest decompression [16, 17]. Some EMS physicians consider this more reliable than needle decompression and less likely to cause lung injury. This technique should be performed only by experienced EMS clinicians with specific training and credentialing. The procedure includes antisepsis of skin, identification of mid‐axillary line just above the nipple line, making a 3–4 cm skin incision with a scalpel, spreading subcutaneous and intercostal tissue with hemostats, and puncture of parietal pleura with finger. The site should then be covered as for a sucking chest wound. Vigilance for reaccumulation of the pneumothorax is essential just as after needle decompression.

Subsequently, the patient should receive a formal thoracostomy tube placed on suction with water seal. This is typically deferred until arrival in the emergency department but may be considered in the prehospital setting under special circumstances (e.g., protracted transport interval) and if appropriately credentialed clinicians and resources are available.

A patient with a penetrating wound to the chest should have an occlusive dressing applied with watchful monitoring for the development of tension physiology. If tension develops, the dressing should be immediately vented. Some types of occlusive dressings provide one‐way air flow (pleural space to environment) to prevent the accumulation of gas in the pleural space that leads to a tension pneumothorax. Alternatively, an occlusive dressing may be left unsealed on one side or corner, which allows it to act like a one‐way flap valve.

A frequent concern with the management of patients with pneumothorax is air transport. Boyle’s law (P1 × V1 = P2 × V2) describes that the air in the pleural space will expand with decreasing atmospheric pressure associated with increasing altitude. The EMS clinician should be aware that helicopter transport is not typically associated with sufficient altitude to have a significant clinical effect. For example, most medical helicopters fly at 1,000–3,000 feet above the ground. But at 6,000 feet, an altitude sometimes associated with instrument flight conditions (e.g., inclement weather), the increase in size would be about 25% (e.g., V2 = P1 × V1/P2 = 760 mmHg × 100 cc/609 mmHg = 125 cc). The clinical effects of such an increase in pneumothorax size are very much patient specific, depending on such things as initial volume, lung compliance, and comorbid conditions. Patients generally should not be flown in fixed‐wing aircraft (especially without cabin pressurization) without tube thoracostomy decompression.