Smoke inhalation

[Dermal and inhalation poisoning. Rare guests in our intensive care units?]

Patients with dermal and inhalation poisoning are uncommon in intensive care treatment. We describe the diagnostics and specific toxicological treatment of patients with hydrofluoric acid burns. For inhalation poisoning, we focus on smoke inhalation, especially the management of cyanide and carbon monoxide poisoning. Special attention is given to the use of hyperbaric oxygenation for the treatment of carbon monoxide poisoning.

Isolated inhalational injury: Clinical course and outcomes in a multidisciplinary intensive care unit

Background and Aims:

Although smoke inhalation is well known to cause acute lung injury, there are few reports in literature that study the evolution, clinical course and outcomes of isolated inhalational lung injury in a modern intensive care setting. A major fire disaster provided us the opportunity to study victims of isolated inhalational injury admitted to our Multidisciplinary Intensive Care Unit (MICU).

Materials and Methods:

We studied the clinical course, ICU and hospital outcomes of 13 victims of a fire disaster who required mechanical ventilation for isolated inhalational lung injury. All patients were followed up at regular intervals, and their functional status was assessed at 8 months after hospital discharge.

Results:

The Lung Injury Scores (LIS) worsened to reach a nadir on Day 3 of injury. There was a significant correlation between the LIS on Day 3 and duration of mechanical ventilation (r = 0.8; P = 0.003), ICU (r = 0.8; P = 0.002) and hospital (r = 0.6; P = 0.02) days. Late-onset airway complications were encountered in four patients. Three of them required long-term artificial airways – two with a tracheostomy while the third patient required surgical insertion of a “T” tube. Persistent problems with phonation occurred in two patients. At 8 months postdischarge, all patients were independent with activities of daily living; all were back to work, except for two who continued to need artificial airways.

Conclusions:

Inhalational lung injury progresses over the first few days and is worst after 72 h. Late-onset airway complications may manifest after several weeks and require repeated intervention.

Análise do lavado broncoalveolar em vítimas de queimaduras faciais graves

OBJETIVO: Analisar o lavado broncoalveolar (LBA) de vítimas de queimaduras que inalaram fumaça a fim de identificar alterações que possam estar associadas à morte ou à sobrevida. MÉTODOS: Dezoito vítimas de queimaduras faciais foram submetidas a LBA até 24 h após o evento, sendo realizadas a análise do conteúdo celular e proteico, incluindo TNF-α, HLA-DR, CD14, CD68 e iNOS. RESULTADOS: Dos 18 pacientes submetidos à broncoscopia, 8 (44,4%) morreram durante o seguimento. A média de idade dos pacientes que morreram foi significativamente maior (44,7 vs. 31,5 anos). A superfície corporal queimada foi em média de 60,1% nos pacientes que morreram e de 26,1% nos sobreviventes (p < 0,0001). Entre os 18 pacientes submetidos à broncoscopia, 11 (61,1%) apresentaram sinais endoscópicos de lesão por inalação de fumaça, e 4 (36,4%) destes faleceram. Dos 7 pacientes sem sinais de lesão por inalação de fumaça, 4 (57,1%) faleceram. A média do número de células epiteliais ciliadas no LBA dos pacientes que morreram foi significativamente maior daquela dos sobreviventes (6,6% vs. 1,4%; p = 0,03). Os demais parâmetros analisados não mostraram diferença entre os grupos. CONCLUSÕES: A superfície corporal queimada mostrou ser um fator preditivo de mortalidade. O aumento do número de células epiteliais ciliadas no LBA, denotando descamação epitelial brônquica, esteve associado à maior mortalidade de pacientes com queimaduras faciais.

Smoke Inhalation

Unfortunately, fires are common events both in urban and rural portions of the United States. Smoke inhalation is the leading fire-related cause of death. The elemental combustion products of fire are light, heat, and smoke. Smoke is a very complex mixture of potentially harmful substances. Although a relatively rare presenting event to small animal hospitals, when animal fire victims do appear, clinicians must know how to recognize the signs of smoke inhalation and how to successfully deal with them. This discussion will investigate the toxic nature of fire smoke, its mechanism of action upon respiratory tissues, the clinical signs displayed, and its diagnosis and treatment. Differential diagnoses of smoke inhalation and prevention and prognosis will also be explored. Veterinary hospitals should have set protocols in place for managing animal victims of smoke inhalation in order to ensure a successful outcome.

[Methods of burn treatment. Part I: general aspects]

Burns and scalds are common injuries that present with a wide range of severity. Correct evaluation of a burn's depth and extent is essential for adequate treatment, not only initially but also for late results. The depth of a burn is classified as first-to-third degree, and its extent can be deducted from specific tables. As a generalised haemodynamic reaction, a capillary leak allows fluid and colloidal substances to leave the intravasal system. This can lead to hypovolemic shock. In the first 24 h, only cristalloid fluid according to Baxter's formula should be administered. Transfer to a burn centre is indicated in accordance with well-defined guidelines. Concomitant injuries, especially inhalation traumata, need to be diagnosed and treated early. By activation of the immune response, a sepsis-like immune response syndrome can occur,resulting in bacterial translocation and colonisation with high mortality rates.

Is high PEEP low volume ventilation in burn patients beneficial? A retrospective study of 61 patients

In burn care lung damage by inhalation injury is a major cause of mortality in burn patients. In the field of intensive care medicine ventilation strategies to reduce lung injury caused by ventilation are under investigation. The promising results of the application of pressure controlled high PEEP low volume (HPLV) ventilation prompted us to use this ventilation strategy in our burn ICU. To establish whether this ventilation regime is beneficial the charts of 61 consecutive patients needing artificial respiration were reviewed. A scoring system for PEEP level and tidal volume was developed and treatment groups with high PEEP and low volume and low PEEP high volume regimes were compared. No statistically significant differences could be found when comparing treatment versus mortality, the number of pulmonary complications or incidence of pneumothoraces. However, the trend showed a benefit in mortality for patients with an ABSI scoring up to 9, but at the same time pulmonary complications increase. The Horovitz oxygenation index showed no advantage for the HPLV Group. In a separate analysis we found a significant correlation between absolute PEEP and mortality. The correlation between PEEP level and mortality is a dynamic factor predicting outcome, This not been described yet and can be an addition to the static ABSI score. Differences between ventilation strategies were not as evident as expected in this retrospective study, so prospective randomized studies are needed.

Using bronchoscopy and biopsy to diagnose early inhalation injury. Macroscopic and histologic findings

OBJECTIVE

To learn the value of bronchoscopy and biopsy in the early diagnosis of inhalation injury ARDS.

SETTING

Burn Center, CHU Saint-Antoine, Paris, France.

DESIGN

130 consecutively admitted burn patients were bronchoscoped on admission.

MEASUREMENTS

The appearance of the bronchial tree was recorded, and biopsies were taken from spurs of the proximal and distal branches of the right bronchi.

RESULTS

Either bronchoscopy or biopsy was positive in 46 cases. Twenty three of 44 patients with chemical inhalation injury developed ARDS (52%). Of 83 negative cases only 6 developed ARDS (7%).

CONCLUSION

Bronchoscopy with biopsy is useful in predicting the development of ARDS in burn patients.

Exosurf treatment following wood smoke inhalation

Pulmonary surfactant deactivation is an important factor in the pathophysiology caused by wood smoke inhalation. Surfactant replacement is beneficial in treatment of surfactant-deficient neonates and possibly the adult respiratory distress syndrome (ARDS). In this study, the effect of exogenous Exosurf treatment for acute wood smoke injury was examined in four groups of rabbits. All groups were anaesthetized, placed on a ventilator, and surgically prepared for haemodynamic, peak airway pressure (P(aw)), and blood gas measurements. Rabbits were monitored for 2 h following smoke or sham smoke inhalation. At the conclusion of the experiment pulmonary oedema and surfactant function were measured. A Control group (n = 5) was followed without intervention. A Smoke group (n = 4) was ventilated with wood smoke for 3 min. A third group (Smoke+Exo, n = 4) was subjected to smoke followed by pulmonary instillation of Exosurf (5 ml/kg). Saline (5 ml/kg) was instilled into the lungs of the fourth group (n = 3) as a control for Exosurf instillation. Saline, Smoke and Smoke+Exo all significantly lowered PO2 and elevated P(aw) compared to baseline and the Control group. Exosurf treatment did not reduce the pulmonary oedema or restore surfactant function caused by smoke exposure. This study indicates that wood smoke inhalation acutely damages the lung and that administration of Exosurf by instillation is not an effective treatment.

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.

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.

Fate of mass burn casualties: implications for disaster planning

A survey of 11 fire disasters which have occurred since 1970, showed that incidents occurring outdoors resulted in larger numbers of hospital admissions, with more severe injuries, than incidents occurring indoors. While the majority of burn casualties sustained burns covering less than 30 per cent body surface area (BSA), outdoor disasters resulted in the admission of a significant number of patients with burns covering more than 70 per cent BSA. Expert triage may therefore minimize the requirement for specialized burn beds. However, the scarcity of burn facilities is such that involvement of distant centres may be anticipated following large disasters. While effective early management extends the time available for the dispersal of casualties, delays may be avoided by prior planning, especially if the international transfer of patients is envisaged.