Medical Aspects of Chemical Warfare (2008) - The Black Vault

Toxic Inhalational Injury and Toxic Industrial Chemicalsbe demonstrated if bronchodilators are tested at thesame time. Substantial airway obstruction may bepresent with little clinical evidence. In all cases ofunexplained dyspnea, regardless of clinical findings,careful pulmonary function measurements should beundertaken. Ideally, these studies should be performedin an established pulmonary function laboratory andwould include lung diffusing capacity for carbonmonoxide and arterial blood gas measurements. Thesestudies should also be performed during exertion ifthe patient has dyspnea on exertion that cannot otherwisebe explained by pulmonary function studiesperformed at rest. 1Bronchoalveolar LavageBronchoalveolar lavage is a diagnostic procedurethat involves washing a sample of cells and secretionsfrom the alveolar and bronchial airspaces. An inflammatoryresponse can be detected by polymorphonuclearleukocytes and an increase in protein contentin the lung washings. Cell death or membrane damagecan be indicated by the release of cytoplasmic enzymesand lactate dehydrogenase into the acellular portionof the lavage fluid. Animals chronically exposed toinsoluble particles show a large increase in some lysosomalenzymes found in the bronchoalveolar lavagefluid. Also, angiotensin-converting enzymes have beenfound to be elevated with endothelial cell damage inthe pulmonary capillaries. Although bronchoalveolarlavage has been used to validate the presence of acutelung injury from TICs, the method is limited by thelarge range of normal values for each parameter. 53Other Tests• Pulmonary capillary wedge pressure shouldbe monitored in cases of severe pulmonaryedema or ARDS.• Ventilation/perfusion scans can show abnormalair trapping in the setting of lower airwayobstruction and may be useful to help gaugeseverity or progress of respiratory disease;however, these findings are unlikely to changeacute medical management.• Carbon dioxide levels should be monitored inpatients with prior lung disease such as asthmaand chronic obstructive pulmonary disease;these patients may be affected more severely andare at greater risk of retaining carbon dioxide.MEDICAL MANAGEMENTLung-damaging TIC casualties may have minimalsigns and symptoms during the acute phase, and theprognosis should be guarded. Ongoing reassessmentis an essential component of the early medical managementof these casualties, for they could rapidly developsevere noncardigenic pulmonary edema. However,many of the casualties who survive for more than 48hours recover without sequelae. A complete medicalhistory is one of the most important aspects in themedical management of these casualties. In contrastto most occupational inhalational exposures, lungdamagingchemical warfare agents need specific immediatetreatment in addition to the usual supportivecare (the suspicion of exposure to lung-damagingchemical warfare agents is of course higher in timesof war or terrorist activity).Patient HistoryCollecting historical data from the casualty is acritical aspect of assessing and treating individualsexposed to lung-damaging agents. No specific statementcan determine the correct diagnosis and ultimatetreatment, but careful questioning of an exposed individualwill often greatly simplify the diagnosis andmedical therapy. Different approaches to collectinga history may be needed depending on the circumstancesof the events involved (see Exhibit 10-1 for alist of example questions). If a casualty is unable toprovide a history of the incident, an observation ofthe scene can be helpful in determining treatment,the amount of time needed for observation, and thelikely prognosis. Other personnel on the scene of theincident, who may have conducted reconnaissance orany atmospheric monitoring, may be able to assist inthe clinical decision making.Physical ExaminationPhysical examination may be particularly difficult inthe event of combined lung-damaging TICs and conventionalinjuries; therefore, it is essential that medicalpersonnel note the patient’s physical condition (specificconditions to look for are listed in Exhibit 10-2).Symptoms of lung-damaging TIC inhalation injuriescan be delayed in onset, but some conditions that mayprecede the onset of delayed symptoms include facialburns, inflamed nares, wheezing, altered mental status,and productive cough. Coughing will more than likelybe the first symptom noted (although an occasional361