Steroid therapy following isolated smoke inhalation injury

The role of steroids following major trauma

This article reviews the indications and evidence for the administration of steroids to patients who have suffered significant trauma. Uncontroversial indications are rare. In spinal cord injury steroids are often given but the practical benefits are questionable. The case for treatment in head injury is unproven. Consideration should be given to treating all those patients who develop acute respiratory distress syndrome (ARDS), although treatment should be deferred to the later (fibroproliferative) stages. The role of steroids in sepsis is complicated and, although steroid administration can have dramatic effects on vasopressor requirements, convincing evidence for mortality reduction is not available.

The wound/burn guidelines - 6: Guidelines for the management of burns

Burns are a common type of skin injury encountered at all levels of medical facilities from private clinics to core hospitals. Minor burns heal by topical treatment alone, but moderate to severe burns require systemic management, and skin grafting is often necessary also for topical treatment. Inappropriate initial treatment or delay of initial treatment may exert adverse effects on the subsequent treatment and course. Therefore, accurate evaluation of the severity and initiation of appropriate treatment are necessary. The Guidelines for the Management of Burn Injuries were issued in March 2009 from the Japanese Society for Burn Injuries as guidelines concerning burns, but they were focused on the treatment for extensive and severe burns in the acute period. Therefore, we prepared guidelines intended to support the appropriate diagnosis and initial treatment for patients with burns that are commonly encountered including minor as well as moderate and severe cases. Because of this intention of the present guidelines, there is no recommendation of individual surgical procedures.

Early single-shot intravenous steroids do not affect pulmonary complications and mortality in burned or scalded patients

BACKGROUND AND OBJECTIVES

Inhalation injury, especially in combination with cutaneous burns, is the major cause of morbidity and mortality in patients admitted to burn care centers. Either with or without the presence of a cutaneous burn, inhalation injury contributes to high risk for developing severe pulmonary complications. Steroids may reduce a prolonged and destructive inflammatory response to toxic or allergic substances. The objective of this study was to evaluate the effect of early single-shot intravenous steroids on pulmonary complications and mortality in burned or scalded patients with or without inhalation injury.

METHODS

Retrospective analysis of a prospective single center database of patients registered between 1989 and 2011 who were admitted to the intensive care unit of our burn care center after burn or scald injury. Uni-variate statistical analysis was performed comparing two groups (steroid treated vs. non steroid treated patients) with regard to clinical outcome. Main parameters were sepsis, mortality and pulmonary complications such as pneumonia, ALI and ARDS. Multi-variate analysis was used by logistic regression with mortality and pulmonary complications as the dependent variables to identify independent risk factors after burn or scald injuries.

RESULTS

A total of 1637 patients with complete data were included in the present analysis. 199 (12.2%) received single-shot intravenous steroids during the prehospital phase of care. In 133 (66.8%) of these patients, inhalation injury was diagnosed via bronchoscopy. Steroid treated patients had sustained a significantly higher severity of burn than non-steroid treated patients (Abbreviated Burn Severity Index 7.1±3 vs. 6.0±2.9; p<0.001). In a multivariate analysis using a logistic regression model early intravenous steroid treatment had no significant effect on pulmonary complications and mortality.

CONCLUSIONS

In our single center cohort of burned and scalded patients single-shot intravenous steroids during the pre-hospital phase of care was not associated with pulmonary complications or mortality.

Protection of Rats Against Perfluoroisobutene (PFIB)-Induced Pulmonary Edema by Curosurf andN-Acetylcysteine

Airborne exposure to lung-toxic agents may damage the lung surfactant system and epithelial and endothelial cells, resulting in a life-threatening pulmonary edema that is known to be refractory to treatment. The aim of this study was to investigate in rats (1) the respiratory injury caused by nose-only exposure to perfluoroisobutene (PFIB), and (2) the therapeutic efficacy of a treatment at 4 and/or 8 h after exposure consisting of the natural surfactant Curosurf and/or the anti-inflammatory drug N-acetylcysteine (NAC). For that purpose, the following parameters were examined: respiratory frequency (RF), lung compliance (Cdyn), airway resistance (Raw), lung wet weight (LWW), airway histopathology; and in brochoalveolar lavage (BAL) fluid, total protein, total phospholipid, cell count and differentiation, and changes in the surface tension of the BAL fluid. The mean (+/- SEM) surface tension of BAL fluid derived from PFIB-exposed (C . t = 1100-1200 mg min(-1) m(-3), approximately 1LCt50; t = 20 min) animals at 24 h following exposure (11 +/- 3 mN/m) was higher than that of unexposed rats (0.8 +/- 0.4 mN/m), reflecting damage to the surfactant system and justifying treatment with exogenous surfactant. Curosurf treatment (62.5 mg/kg i.t.) decreased pulmonary edema caused by PFIB, reflected by a decreased LWW, and decreased the amount of protein in BAL fluid. NAC treatment (1000 mmol/kg ip) inhibited the interstitial pneumonia reflected by a decreased percentage of neutrophils in the alveolar space. It was concluded that a combined treatment of Curosurf + NAC improved respiration, that is, RF and Cdyn, whereby Curosurf predominantly decreased pulmonary edema and NAC predominantly reduced the inflammatory process. A combined treatment may therefore be considered a promising therapeutic approach in early-stage acute respiratory distress caused by PFIB, although the treatment regimes need further investigation.

Management of burn wounds in the emergency department

This article makes some introductory comments on the histology of the skin and the pathophysiology of burn injury as these topics pertain to the estimation of the depth of the burn injury. The definition of a major burn and the salient points of its treatment are covered. In addition, some general comments are made about several special injuries for which burn center referral usually is sought. Finally, guidance is given in the selection and treatment of patients who have burns that may be treated on an outpatient basis.

Isolated smoke inhalation injuries: Acute respiratory dysfunction, clinical outcomes, and short-term evolution of pulmonary functions with the effects of steroids

Relatively few reports exist regarding isolated smoke inhalation injuries in human patients. In this study, we describe the acute manifestations and short-term evolution of respiratory injuries after isolated smoke inhalation in victims of fires. Ninety-six patients admitted as the result of a subway fire were examined for acute respiratory dysfunction with clinical outcomes. Some of the survivors suffering from less severe injuries were evaluated for changes in pulmonary function over time, with the effects of steroid treatment. In 13 patients (14%), immediate respiratory failure resulted from ventilatory insufficiency, which was induced principally by mechanical airway obstruction, and manifested as significantly lowered pH and higher PaCO2 levels than in the patients requiring no mechanical ventilation. Toilet bronchoscopy allowed for early liberation from mechanical ventilation. Along with the death of 4 patients (4%), vocal cord and tracheal stenosis were noted in 5 patients and 1 patient, respectively, among 17 patients for whom endotracheal intubation was required. Pulmonary functions improved significantly after 3 months, with no further changes being observed within the subsequent 3 months. Steroid therapy resulted in no additional improvements in the pulmonary functions of these patients. In patients with isolated smoke inhalation injuries, immediate ventilatory insufficiency resulting from mechanical airway obstruction should be watched for, and managed via toilet bronchoscopy. Vigilance is required to avoid airway complications after endotracheal intubation. The improvement of pulmonary functions progressed primarily within the first 3 months, whereas short-course steroid therapy exerted no influence on the eventual recovery of pulmonary functions in the less severe cases.

The effect of perfluoroisobutene and phosgene on rat lavage fluid surfactant phospholipids

1. This study investigated whether the reactive organohalogen gases perfluoroisobutene (PFIB) and phosgene, which cause death by overwhelming pulmonary oedema, affect the surfactant system or type II pneumocytes of rat lung. 2. The progression and type of pulmonary injury in Porton Wistar-derived rats was monitored over a 48 h period following exposure to either PFIB or phosgene (LCt30) by analyzing the inflammatory cells and protein in bronchoalveolar lavage fluid. Six rat lung phospholipids were measured by high-performance liquid chromatography, following solid phase extraction from lavage fluid. 3. Alterations in the cell population and lung permeability occurred following both gases, indicating that the injury was a permeability-type pulmonary oedema. Changes in the total amount of phospholipid and in the percentage composition of the surfactant were different for the two gases. PFIB produced increases in phosphatidylglycerol and phosphatidylcholine over the first hour, similar to that seen following air exposure, followed by substantial decreases in these phospholipids. Phosgene caused late increases in all phospholipids from 6 h post-exposure. 4. Differences in the response of the surfactant system to exposure to PFIB and phosgene suggest different mechanisms of action at the alveolar surface although the final injurious response is pulmonary oedema for both gases.

Anesthesia and pain management in pediatric burn patients

Patients with severe burn injury are a challenge for the pediatric anesthesiologist. Today with adequate care many children survive their trauma and have a good chance for complete functional and psychological rehabilitation. The anesthesiologist has to provide excellent care even for patients in suboptimal or unstable condition to enable wound debridement and grafting, because only rapid skin closure will stabilize the patient. Adequate pain treatment during all phases of burn treatment is mandatory.

The utility of parenteral glucocorticoids in the emergency department

Exogenous glucocorticoids have wide clinical applicability in emergency medicine. Many uses reported for this class of drugs are supported by only anecdotal evidence of efficacy, while others have been proven or disproven by well-designed studies; this evidence is evaluated here. Because adverse effects are relatively common and may be serious after initiation of steroid therapy in the emergency department, it is important for the emergency physician to review systematically the indications, contraindications, and precautions for the use of parenteral glucocorticoids.

Smoke inhalation: diagnosis and treatment

Smoke inhalation, defined as airway or pulmonary parenchymal injury resulting from the inhalation of toxic combustion products, presents with a wide range of severity in patients with and without skin burns. In patients with severe injuries, the diagnosis is obvious on the basis of the history and clinical presentation; in patients with less severe injuries or those in whom the clinical consequences are delayed, diagnostic precision is difficult because diagnostic clues provide only indirect information. There is no specific treatment so diagnosis is not critical for patient management. Patients at risk include 20% to 30% of flame burn victims who should receive vigorous supportive care. The mortality rate of smoke inhalation victims without a burn is < 10%. With a burn the mortality rate is 30% to 50%, suggesting that thermal injury or its treatment is responsible for further lung damage. Endotracheal intubation provides definitive treatment for obstructed or soon-to-be obstructed patients. However the diagnosis of smoke inhalation per se is not an indication for airway intubation and respiratory support; 12% of patients without a burn require intubation versus 62% of those with a burn. A translaryngeal tube can be converted to a tracheotomy safely in burn victims; tracheotomies are easier to manage if burns of the neck are excised and grafted prior to placement. Mechanical ventilation with positive end expiratory pressure (PEEP) is the treatment for the pulmonary injury. The early lesions of smoke inhalation often progress in the context of sepsis and other complications of the burn illness to a clinical state consistent with adult respiratory distress syndrome.

Resuscitation in northern Iraq

The principles of Advanced Trauma Life Support (ATLS) were adopted by a Royal Navy surgical team deployed to northern Iraq. Over a 6-week period, 18 casualties of both military and civil trauma required active resuscitation, 10 being under the age of 16 years. Triage of multiple casualties was necessary on three occasions. Two patients died. It was difficult to exclude cervical spine injury. Venous cut-down was frequently unsuccessful, so that internal jugular vein cannulation was life-saving. Crystalloid was used as the primary infusion without apparent disadvantage. Cross-matched blood was unavailable and one patient died with haemolysis after massive transfusion. Hypothermia was a problem despite the high environmental temperature. Laboratory and radiological facilities were extremely limited. Non-medical staff were trained most effectively to assess vital signs, although sophisticated monitors became available. These problems are discussed and compared with previous experience. Recommendations are made to improve future outcome.

Protection by cysteine esters against chemically induced pulmonary oedema

Perfluoroisobutene (PFIB) is a hydrophobic reactive gas produced by the pyrolysis of polytetrafluoroethane which induces pulmonary oedema similar to that induced by phosgene when inhaled. When a lethal dose is inhaled by Porton strain rats total non-protein thiol (NPSH) and glutathione (GSH) in the lung are reduced by between 30 and 49%, respectively. If the endogenous levels of thiols in the lung are reduced by pretreatment with buthionine sulfoximine (BSO) 16 hr before exposure to PFIB, the rats become more susceptible to the effects of the gas. The effect of BSO pretreatment on toxicity was prevented by pretreatment 30 min before exposure, with 5 mmol/kg N-acetylcysteine (NAc). NAc increased the levels of cysteine (CySH) in the lung by 150% and GSH was unaffected. Similarly pretreatment with 3 mmol/kg CySH also protected against toxicity and raised CySH levels by 100%. A series of cysteine esters and cystine dimethyl ester (CDME) have been synthesised which selectively raise lung levels of CySH in the rat lungs after intraperitoneal (i.p.) injection. The methyl ester and CDME raised lung levels of CySH by 4000 and 2000%, respectively, 10 min after i.p. injection whilst GSH levels remained unchanged. Cysteine isopropyl ester raised lung levels of CySH by 10,600% but liver levels by only 1400%. All esters except the t-butyl ester (CTBE) also raised maximal plasma levels of NPSH by up to 500%; however, when NAc was injected plasma levels increased by over 1500%. Rats treated with these esters at 3 mmol/kg and with NAc at 5 mmol/kg were protected against lethal doses of PFIB in all cases except when CTBE was used. It appears that these cysteine esters may distribute preferentially into the lung, unlike NAc. The selective enhancement of pulmonary CySH levels may provide a method for the protection of lungs against inhaled reactive toxicants by increasing intracellular CySH. Levels of CySH may also be raised in epithelial lining fluid thus reducing access of gaseous toxicants to pulmonary tissue.

Methylprednisolone does not protect the lung from inhalation injury

Most clinical studies suggest that corticosteroids are contraindicated in the treatment of acute smoke inhalation. However, they are still used in critical situations with the hope that they might reverse the acute pathophysiological responses to smoke inhalation and thus reduce the severity of the illness or make survival possible. These experiments were done to study the effect of methylprednisolone on the response to smoke inhalation in anaesthetized mongrel dogs. Three experimental protocols were followed: (I) haemodynamics, gas exchange, lung compliance, and lung water were evaluated; (II) pulmonary vascular permeability was assessed by cannulating the afferent tracheobronchial lymphatic and calculating the osmotic reflection coefficient (sigma d) at high lung lymph flows; (III) pulmonary surfactant function was studied using a Wilhelmy balance. Methylprednisolone alone did not alter any measured values compared with those seen in control animals. Treatment with methylprednisolone (30 mg/kg) prior to smoke exposure did not attenuate any of the adverse responses typically seen after smoke inhalation. These data indicate that methylprednisolone does not protect the lung from the acute physiological consequences of inhalation injury.

Smoke inhalation injury

Smoke inhalation injury is responsible for more deaths after fire than actual body burns. Many of the effects of heat and chemical burns to the airways are delayed and may not be clinically evident at first. Chest films are often not helpful, and direct laryngoscopic or bronchofibroscopic examination or a ventilation-perfusion scan may be necessary to verify the diagnosis. Treatment depends on the components involved, with chemically induced airway injury being the most complex to manage. Death rates remain high when inhalation injury is combined with severe body burns.

Manchester air disaster

On 22 August 1985 a fire occurred on a Boeing 737 jet airliner at take off at Manchester Airport. One hundred and thirty seven passengers and crew were on board. Fifty two passengers died on the aircraft, 85 escaped. Most survivors had minor physical injuries, but 15 required admission to hospital because of smoke inhalation and two of these had severe burns. At presentation only one survivor required ventilation but within 12 hours a further five required ventilation. Although initially patients suffering from smoke inhalation may seem relatively well, lung function may deteriorate rapidly in the first 24 hours. Careful organisation and regular practice of procedures to deal with a major accident are essential to be able to respond adequately to such an event.

Smoke inhalation injuries

Up to a third of all victims of major burns suffer smoke-related injury and may die as a result of inhalation injury. The management of the upper airway depends on a thorough understanding of the mechanisms of injury, including carbon monoxide toxicity, thermal injury, and smoke inhalation. Establishing and maintaining an airway for resuscitation requires a high index of suspicion, as early and severe upper airway swelling may preclude safe intubation under direct vision. Nasotracheal intubation is preferred in burn patients but is only indicated for patients in acute respiratory distress and a select group at high risk for developing progressive upper airway compromise and pulmonary injury. The use of the flexible bronchoscope and nasopharyngoscope is a safe and effective means of evaluating the respiratory tract and assisting in pulmonary therapy. Early tracheotomy is indicated only in rare cases because of increased morbidity and mortality in burn patients. The use of steroids is still controversial and is probably indicated only for refractory bronchospasm or secretions. Aggressive evaluation and management of inhalation burns will reduce the mortality rate of a frequently fatal injury.

Aspiration pneumonia and complications of inhalation of smoke and toxic gases

Pulmonary aspiration of oral, esophageal, or gastric content poses a significant hazard to animals. Aspiration of acidic, alkaline, or ingesta-containing gastric contents can cause serious morbidity and mortality. Clinicians must be aware of conditions and clinical situations in which there is increased risk of aspiration. The most important aspect of the mitigation of the pneumonic complications of aspiration is prevention.

Inhalation of products of combustion

The atmosphere of a fire is deadly to breathe. Firefighters or building occupants may be victims of the heat, irritating smoke, depleted oxygen, carbon monoxide, and such other toxic gases as cyanide, hydrogen chloride, and acrolein. Increasing numbers of homes and public buildings are being built and furnished with highly flammable synthetic materials that give off copious smoke and toxic gases when burned. Whether or not there are cutaneous burns, the possibility of inhalation injury must be considered in any fire victim. All victims of a fire environment should be presumed to have CO intoxication and should be treated with 100% oxygen until the HbCO level is within normal limits. In an extreme situation, cyanide intoxication should be suspected and administration of sodium thiosulfate may be lifesaving. Upper airway occlusion may result from thermal damage or edema secondary to burns from soluble toxic gases. Chemical injury to the lower airway and alveoli may result from inhalation of insoluble irritant gases and toxic gases adsorbed on carbon particles. Upper respiratory tract obstruction may be suggested by the clinical presentation (eg, pharyngeal burns, stridor, hoarseness, dysphagia), but only by means of fiberoptic bronchoscopy can it be recognized or excluded with certainty. Intubation may be necessary. Lower respiratory tract injury may be manifest clinically by dyspneas, wheezing and chest tightness, as well as by hypoxemia and reduced FEV1 and FVC. Treatment is symptomatic, but close observation for progressive respiratory insufficiency is necessary.