INTRODUCTION

TOP ABSTRACT INTRODUCTION DISCUSSION REFERENCES

Sand aspiration during drowning and near-drowning is an uncommon yet important consequence of these events that may be overlooked if not suspected. The reported radiographic findings in such patients have been limited to chest roentgenograms only, and to our knowledge, the endobronchial findings have not previously been detailed. We report for the first time in combination the radiographic, computed tomographic (CT), bronchoscopic, and microbiologic findings in a patient who suffered sand aspiration.

	CASE SUMMARY

A 26-yr-old woman without a prior medical history was involved in a motor-vehicle accident during which the automobile she was driving traveled down an embankment and submerged upside-down in a river bed. She was extracted from the car after approximately 5 min by a volunteer firefighter who witnessed the accident. The woman was unresponsive, hypotensive, and required endotracheal intubation at the scene by rescue personnel. Upon her arrival at our institution's emergency department, the patient's Glasgow coma scale was 5 and her vital signs consisted of a blood pressure of 145  / 110 mm Hg, a pulse of 119 beats /min, a temperature of 96.9 ° F (36.1° C), and respirations of 20 breaths/min. Chest auscultation demonstrated decreased breath sounds bilaterally, with expiratory wheezing. Initial attempts at mechanical ventilation were difficult because of increased peak airway pressures (range: 80 to 90 cm H₂O) on an assist control mode (tidal volume: 650 ml, rate: 16 respirations/min, and positive end-expiratory pressure [PEEP]: 5 cm H₂O). Endotracheal suctioning yielded large but unquantified amounts of sand and gravel obstructing the endotracheal tube and upper airway. After repeated suctioning (six times) and removal of the foreign material, peak airway pressures decreased to 50 cm H₂O. An initial arterial blood gas measurement obtained during administration of 100% oxygen showed a pH of 7.19, Pa_CO2 of 47 mm Hg, and Pa_O2 of 155 mm Hg.

A chest radiograph obtained upon arrival of the patient at the emergency department 1 h after the accident revealed sand in the gastric fundus, and sand bronchograms in the right lower lobe (Figure 1). Computed tomography (CT) of the chest confirmed bilateral lower-lobe consolidation and the high-attenuation, radiodense material within lower lobe bronchi (Figure 2). A CT of the head, obtained to rule out significant cranial injury, showed air-fluid and fluid-sand levels in the right maxillary sinus (Figure 3). This material was drained via a Caldwell-Luc procedure on the second day of hospitalization.

View larger version (106K): [in this window] [in a new window]   Figure 1.   Chest radiograph taken within the emergency department, showing sand bronchograms in the right lower lobe (solid arrow). Note sand within the gastric fundus (open arrow).

View larger version (93K): [in this window] [in a new window]   Figure 2.   Chest CT scan showing bilateral sand bronchograms within the lower lobes (solid arrows) as well as significant air space opacification.

View larger version (98K): [in this window] [in a new window]   Figure 3.   CT scan showing air-fluid-sand levels within the right maxillary sinus (black arrow).

Diagnostic and therapeutic fiberoptic bronchoscopy were performed upon the patient's arrival at the intensive care unit. Tracheobronchial examination revealed severe, diffuse, hemorrhagic inflammation (Figure 4) and marked mucosal friability, which tended to worsen as alveolar lavage continued. Scattered throughout the airway were multiple fragments of gritty particulate matter and sand, which increased in quantity with subsequent bronchoalveolar lavage (BAL). Repeated BAL with a large (6-mm; 2.8-mm inner channel) bronchoscope permitted removal of a moderate amount of this foreign material (Figure 5). BAL was performed with 200 ml normal saline, with a total recovery of 150 ml (75%). The patient's peak airway pressures decreased further, to 35 to 40 cm H₂O, following bronchoscopy. BAL and sinus lavage were performed to evaluate the flora of aspirated pathogens and help guide antibiotic therapy, and cultures of the lavage fluids demonstrated numerous microorganisms (Table 1). Cytopathologic review of the BAL fluid (BALF) demonstrated heterogeneous inorganic and plant material on a background of inflammatory cells.

View larger version (121K): [in this window] [in a new window]   Figure 4.   Fiberoptic bronchoscopy, demonstrating pieces of sand (black arrows), significant airway erythema, and inflammation following near-drowning and sand aspiration.

View larger version (115K): [in this window] [in a new window]   Figure 5.   Sample of endobronchial/alveolar lavage material removed from patient during fiberoptic bronchoscopy following sand aspiration (A). Lavage sample after removal of supernate (B).

The patient became febrile (39.2° C) within 12 h after her admission, and empiric treatment with broad-spectrum antibiotics (piperacillin sodium and gentamicin) was initiated prior to the availability of bronchoscopy culture results. A left shift (39% bands) in the white blood cell (WBC) count developed within the first 24 h, although the patient's absolute leukocyte count remained around 10,000 /µl. Her temperature reached a maximum of 40.0° C during the first day, and she remained febrile throughout the first 9 d of her hospitalization. Serial chest radiographs showed resolution of sand bronchograms by the 2nd day. The patient's acute lung injury required mechanical ventilation for 1 wk. Her remaining hospital course was unremarkable, and she was discharged in good health 3 wk after her near-fatal accident.

The patient was seen at follow-up 6 mo after her discharge. She reported that she had continued to expectorate sand for 3 mo following her hospital discharge. Because of the severity of her injury, follow up chest CT was performed and demonstrated minor opacities thought to represent atelectasis and/or scarring; no residual sand was identified. Pulmonary function studies demonstrated normal spirometry, helium-dilution lung volumes, diffusion capacity, and arterial blood gases.

	DISCUSSION

TOP ABSTRACT INTRODUCTION DISCUSSION REFERENCES

Despite the high incidence of drowning and near-drowning, and a reported 60% frequency of aspiration of mud, sand, and aquatic vegetation during such episodes, cases of significant sand aspiration following near-drowning are rare (1). There are remarkably few published reports detailing the presentations and clinical courses of such patients. Hewer described a drowning victim who was difficult to ventilate during cardiopulmonary resuscitation and whose mouth and pharynx were obstructed by sand (2). Bonilla-Santiago noted chest radiographic findings in two patients with sand aspiration (3). The first was a young man whose body was recovered 48 h after saltwater drowning. Postmortem chest radiographs revealed dense tracheobronchial opacification, which was confirmed to be impacted sand. The other patient had near-drowning and underwent bronchoscopy after an initial chest radiograph demonstrated a small sand bronchogram. Small amounts of sand were removed with lavage and the patient recovered without sequelae.

Four cases of sand and gravel aspiration after accidental burial have also been reported (4). In three of these, the patients required emergency airway management followed by bronchoscopy for removal of aspirated material. Another patient, who was a child, recovered after supplemental oxygen and chest physiotherapy. In each case the chest radiograph demonstrated "classic" sand bronchograms, with radiodense material lining the central tracheobronchial tree. In one patient, cardiopulmonary bypass during bronchoscopy was beneficial in facilitating the removal of aspirated material (4).

Chest radiographic findings in victims of drowning and near-drowning range from normal to a spectrum of abnormalities. The most common abnormality is described as fluffy, nodular, confluent perihilar opacities consistent with pulmonary edema. The apices, bases, and lateral lung fields tend to be spared, and air bronchograms may be prominent (9, 10). Our patient had a surprisingly unremarkable initial chest radiograph except for the relatively subtle sand bronchograms seen in the bases bilaterally and sand within the fundus of the stomach. Her CT scans, obtained to evaluate the extent of trauma, clearly demonstrated radiodense material filling the lower-lobe bronchi and right maxillary sinus. To our knowledge, this is the first time that such findings have been reported.

Concurrently, bronchoscopy revealed severe diffuse airway inflammation, erythema, and mucosal friability. Localized injury is well described in patients having aspirated foreign objects, but the bronchoscopic manifestations of sand aspiration have not been reported in detail (11). It is likely that the extensive airway injury seen in our patient reflected combined effects of direct epithelial damage from aspirated sand, organic material, and water. Freshwater drowning has been demonstrated to cause swelling and subsequent sloughing of respiratory epithelium in rats, and similar changes are believed to occur in humans (12). Pneumonia may complicate the aspiration of fresh- or saltwater and, depending on the water source, may be caused by a variety of microorganisms including bacteria, fungi, and mycobacteria (13). In this regard, the imposing number and concentrations of pathogens isolated from our patient were remarkable, and influenced decisions about her antibiotic therapy. She received empiric antibiotics after quantitative bacterial cultures were obtained during bronchoscopy, although the benefits of prophylactic antibiotics in this clinical setting are unclear (14, 15).

This patient raises several other important issues relating to the evaluation and management of sand aspiration. Sand aspiration is probably underdiagnosed and should be suspected in all patients being treated for near-drowning or accidental burial. Its precise contributions to airway injury or superimposed infections and noninfectious complications are unknown. Initial clues to significant aspiration include increased peak airway pressures during mechanical ventilation, and radiodense linear opacities, or "sand bronchograms," on chest radiography. These densities can be clearly demonstrated on chest CT if not readily visible on plain films. Chest CT should not be performed routinely in near-drowning victims in whom sand bronchograms are readily visible on plain chest radiography. Imaging of the sinuses should be considered to assess possible nasal inhalation of foreign material. Fiberoptic bronchoscopy may be useful in determining the extent and severity of airway injury, for therapeutic clearing of aspirated sand and gravel, and in evaluating for bacterial aspiration through quantitative cultures. Bronchoscopic removal of sand should be performed only when the patient's respiratory status has been compromised by such aspiration. Otherwise, vigorous efforts to clear aspirated sand from an asymptomatic patient are probably not indicated. The patient described here developed acute lung injury requiring extended mechanical ventilation. In the absence of extensive published experience to help guide the management of these patients, strategies for ventilatory support and the use of PEEP are derived from principles developed for the treatment of acute lung injury in other settings. The use of empiric antibiotic therapy seems appropriate in near-drowning victims if bacterial cultures are obtained prior to the initiation of such therapy, with plans to adjust or discontinue therapy based on culture results. Whether bronchoscopy and its diagnostic and therapeutic applications truly benefit the victim of near-drowning remains to be established.

Although a relatively uncommon occurrence, sand aspiration in the near-drowning victim should be excluded because of the spectrum of injuries it may produce. Acute respiratory failure secondary to inadequate ventilation may develop if the oropharynx and upper airway are occluded by sand. Damage to the bronchioles and alveoli can result in significant airway inflammation and acute lung injury requiring prolonged mechanical ventilatory support. The development of pneumonia or sinusitis is likely if the aspiration of foreign material into the airway and sinuses is accompanied by a large innoculum of infectious pathogens. Despite the diagnostic and therapeutic challenges presented by victims of near-drowning, complete resolution without long-term sequelae even of severe respiratory failure is feasible if supportive care is directed toward each of these problems.