Inhalation injury refers to the inhalation of toxic fumes or chemicals on the respiratory tract caused by chemical damage, severe cases can directly damage lung parenchyma. Which occurred in a large area, especially in patients with head and face burns.
First, prevention:
1. Prevention of infection: After inhalation injury, since the airway and lung damage, destruction of ciliary function, airway secretions and foreign bodies can not be discharged, local and systemic resistance to decline, often caused by airway and lung infections. Once infected, if not treated early, can be complicated by acute respiratory failure, and has become an important focus of systemic infection, induced sepsis.
2. The complete removal of foreign body airway mucosal tissue necrosis and shedding, unobstructed drainage, basic infection prevention and control measures, followed by strict aseptic technique and disinfection and isolation, strict control of the wound - the lungs - wound bacterial cross-infection; for regular gas secretions smear and culture, sensitive antibiotics. In addition, general supportive therapy should be strengthened in order to improve immune function, prevention and treatment of infections to be rational sense.
First, the treatment:
1. To maintain airway patency, prevention and relief of obstruction
1) endotracheal intubation and tracheostomy:
Tissue damage due to inhalation, mucosal edema, secretions plugging, bronchial spasm, airway obstruction can occur early, it should be timely endotracheal intubation or incision to relieve obstruction, maintain airway patency. Endotracheal intubation indications:
In particular, the nose and mouth face severe burns, there are those who may laryngeal obstruction.
Glottal edema aggravated.
Airway secretions from the difficulties, wheezing and hypoxia were aggravated. Endotracheal intubation difficult too long retention time (usually no more than a week), as it may aggravate the throat edema, or cause throat ulcers, and even legacy narrowing of the glottis.
The indications for tracheostomy:
Glottis edema or more severe and accompanied by the face and neck ring eschar.
Severe bronchial mucus drain persons.
The combined ARDS require mechanical ventilation.
With severe traumatic brain injury or cerebral edema.
Indwelling intubation time more than 24 hours. Tracheotomy, the obstruction can be lifted immediately, and to facilitate the medicine into the trachea lavage, bronchoscopy and facilitate mechanical ventilation. But tracheotomy airway and lung infections also increased opportunities, as long as normal operation, and postoperative care, strengthening preventive measures, can be avoided.
2) eschar open decompression surgery:
Inhalation injury neck, chest and abdomen annular eschar who may compress the airway and blood vessels, limiting the scope of the thorax and diaphragm activity, affect breathing, increased breathing difficulties, reduced blood supply to the brain, causing cerebral hypoxia, therefore, the above time line parts of the eschar incision decompression, to improve respiratory function, prevention of brain hypoxia, is important.
3) drug treatment:
Bronchial spasm available aminophylline 0.25g slow bolus every 4 to 6 hours. Or salbutamol aerosol spray, bronchial dilation can relieve spasm. If sustained episodes of bronchospasm, may be given hormone therapy, and hormone having capillary permeability enhancement prevents acute inflammation symptoms, reduce swelling, maintain the stability of pulmonary surfactant and a stable lysosomal film role. Because the hormone increased the incidence of lung infection, so the idea of early bolus intravenous dexamethasone stronger than hydrocortisone efficacy. ZHU Pei-fang and other reports of severe smoke inhalation injury in dogs, taken early dexamethasone, 654-2 and oxygen and other comprehensive treatment, can accelerate the CO discharge and improve lung function.
⑷ wet atomization: wet in favor of the trachea, bronchial mucosa is not damaged due to dry, cilia activity help enhance capacity to prevent secretions dry scab, to prevent the mucus plug, prevention and mitigation of atelectasis lung infection has Significance. By inhalation may airway medications to spasm, reduce swelling, prevent infection, and other beneficial mucus discharge. Generally with NS 20ml within plus dexamethasone, gentamicin, α- chymotrypsin each one for inhalation.
2. Ensure volume
Improve pulmonary circulation in the past that, after inhalation injury due to pulmonary capillary permeability, fluid extravasation, prone to pulmonary edema, it should be early stage shock resuscitation fluid volume limit, to prevent induced pulmonary edema, this understanding is one-sided because with inhalation injury skin surface burns, bodily fluids from the body surface burn area not only lost, but also lost from damaged airways and lungs, and therefore, should be based on urine output, blood pressure and vital signs change, correct fluid resuscitation, maintaining adequate blood volume to avoid restrictions infusion, unable to maintain effective circulating volume, will eventually lead to poor tissue irrigation fluid, further aggravating tissue damage.
Pulmonary circulation is a low-voltage, low resistance, high-velocity systems, inhalation injury may increase pulmonary vascular resistance, low blood volume will further reduce pulmonary artery pressure, resulting in pulmonary disorders as well as right heart failure, therefore, can be used cardiac drugs, such as poisonous hairs spin Hanako glycosides K and hair flower prop glycosides (cedilanid) to improve pulmonary function. Dextran can reduce blood viscosity, reduce red blood cell aggregation, beneficial to improve microcirculation.
3. Maintain gas exchange function, correct hypoxemia.
1) gas treatment:
Oxygen concentration: the concentration of oxygen can be divided into low concentration (24% to 35%), moderate concentration (35% to 60%), a high concentration (60% to 100%) and hyperbaric oxygen (2 ~ 3atm) four kinds . The oxygen concentration is calculated:
Oxygen concentration (%) = 21% + 4 × oxygen flow
Purpose is to make oxygen PaO2 increased to normal levels. If reduced PaO2, PaCO2 normal or low concentrations can to moderate concentrations of oxygen inhalation; when subject to hypercapnia or respiratory failure, controlled oxygen therapy should be taken that the oxygen concentration should not exceed 35%. ② time oxygen: oxygen is generally believed that for a long time, the oxygen concentration should not exceed 50% to 60%, the time should not exceed 1, 2009, it shall not be more than four hours when inhaling pure oxygen. Inhalation of high concentrations of oxygen for a long time can damage the lungs, chest pain and cough light, there may be severe lung compliance, increased difficulty in breathing, muscle weakness, mental confusion and even death. ③ oxygen Methods: In addition to nasal oxygen catheter, there are oxygen mask, oxygen and mechanical ventilation method account. Respiratory dysfunction caused by inhalation injury, the use of nasal cannula or oxygen mask is often ineffective, generally required positive pressure oxygen and mechanical ventilation.
2) mechanical ventilation:
Patients often occurs after inhalation injury with varying degrees of respiratory insufficiency, if not treated in time, there may be life-threatening respiratory failure. Respirators are an effective measure to treat respiratory failure. Mechanical breathing through a respirator to complete. Use respirators to patients with mechanical ventilation, improve ventilation and ventilatory function, maintain effective ventilation to correct hypoxia, preventing carbon dioxide retention.
Mechanical ventilation is a symptomatic treatment and emergency rescue measures and grasp the opportunity to use the very reason to be. Respirators indications are as follows:
Clinical manifestations: patients with dyspnea, respiratory rate greater than 35 beats / min, blurred consciousness, irritability, tracheotomy, eschar and reduced pressure to ease after oxygen therapy is still not within the respiratory tract shedding of necrotic tissue prolapse, and secretions inability to cough and so on.
Blood gas analysis: by giving high concentrations of oxygen buckle, PaO2 PaCO2 still lower than 7.8kPa or greater than 6.5kPa.
Pulmonary signs and X-ray film: when the patient respiratory failure, early chest radiograph showed low transparency, increased lung markings, thickening, does not match with the signs of breathing difficulties. When the lungs dry, moist rales, chest clouds appear like shadows, more advanced stage.
Although mechanical ventilation can improve respiratory function, but increase the chance of lung infection, so the mechanical and piping cavity should be thoroughly disinfected, to master the correct procedures to prevent cross infection and reduce the chance of lung infection.
The most commonly used mechanical breathing two positive pressure ventilation and high-frequency ventilation. Positive pressure ventilation: Respirator clinical application of mostly positive pressure respirator. Mechanical positive pressure breathing, positive pressure gas is fed into the lungs, lungs and intrathoracic pressure increased. Thus, the circulatory and respiratory systems can have adverse effects. It should be strictly controlled contraindications. Where can condition airway pressure in heavy disorders; such as bullae, high grave pneumothorax, hemoptysis and acute myocardial infarction who were unfit for use.
Intermittent positive pressure breathing (IP PB): a positive pressure inspiratory pressure within the lungs, exhale reduced to atmospheric pressure, the gas by elastic recoil of the chest and lung tissue discharged.
End inspiratory positive pressure breathing (EI PB): end-inspiratory, expiratory before exhalation valve remain closed a transient, then exhale, expanding the use of small airways, increases the effective ventilation.
PEEP breathing (PE EP): inspiratory positive pressure, the pressure inside the lungs, when expiratory airway pressure is still higher than the atmospheric pressure, so that part due to bleeding, atelectasis and other reasons to promote ventilation function alveolar expansion, increasing the gas exchange surface and improve the blood oxygen levels.
Intermittent intense breathing (IMV): mechanical breathing frequency is half the frequency of normal breathing or 1/10. When the respirator is not aspirated, the patient can be spontaneous breathing exercise. Thus, with the condition improved, autonomous breathing recovery, can evacuate respirator.
Respiratory delay: expiratory mouth area plus aperture cover, so that the discharge resistance is increased in exhaled breath, prolonged breath, this time to prevent the collapse of small bronchi breath.
Intermittent positive pressure breathing is a common way, while positive pressure oxygen. When after intermittent positive pressure breathing, and given the high concentration of oxygen, PaO2 still below the 6.7 ~ 8kPa, should be changed to positive end expiratory pressure. Use should be closely observed changes in cardiovascular function in the patient, pay attention to patient blood, blood pressure and pulse rate changes were observed jugular vein distention, so that timely adjustment of pressure. PEEP value, generally 294 ~ 784Pa, should not exceed 1.5kPa, when excessive pressure and excessive gas, can cause varying degrees (HFV): respiratory rate greater than 60 times per minute, it is called high frequency ventilation . It has a low airway pressure, lower pulmonary artery pressure, cardiac positive pressure ventilation (HFPPV). Clinical commonly used high-frequency jet ventilation.
Ways to connect high frequency ventilation percutaneous intratracheal law, the law bronchoscope through the nose and mouth airway law by nasopharyngeal catheter and the most commonly used jet needle and endotracheal or tracheostomy tube connection method. High frequency jet ventilation in clinical frequency range is generally from 120 to 200 beats / min.
HFV despite its advantages, but it also has its drawbacks. Such as the ability to overcome airway resistance is poor, poor carbon dioxide emissions. But carbon dioxide diffusing capacity of about 20 times greater than oxygen, so early use does not produce carbon dioxide retention. If used interchangeably with positive pressure ventilation, it can compensate for its carbon dioxide emissions caused by hyperventilation too many deficiencies. In addition, high frequency ventilation, there are still some problems, such as wet, alveolar collapse, and changes in lung compliance, so the long-term should be used with caution.
3) pull the clutch membrane (membrane oxygenation):
Membrane oxygenator (membrane oxygenation, ECMO) is a collagen membrane composed of multi-unit parallel between the membrane and the membrane overflow with a thin layer of blood, oxygen and blood flow is not in direct contact. The treatment principle is the patient's blood in vitro oxygenation temporarily replace lung function, mechanical ventilation can prevent lung damage, and reduce the load on the lungs, lung disease conducive to treatment and recovery.
Membrane oxygenator is mainly used for the treatment of acute respiratory failure, for the treatment of inhalation injury reported rarely.
