Ultrasonographic bedside evaluation of maxillary sinus disease in mechanically ventilated patients

Maxillary sinusitis in patients ventilated for a severe head injury and with nostrils free of any foreign body

BACKGROUND

This study aims to determine the frequency of maxillary sinusitis in the patients with traumatic head injury and nostrils free of any foreign body. In addition, the sensitivity and specificity of ultrasonography (US) for the detection of the presence of fluid in maxillary sinuses were evaluated.

PATIENTS AND METHODS

Forty patients with severe traumatic head injury were included in the study. The patients who had displaced maxillary sinus fracture at the medial wall and naso-tracheal and/or naso-gastric tube were excluded. Paranasal computed tomography (CT) was performed along with the routine cranial CT scanning or in case of unknown source of infection and compared with the results of ultrasonographic examination of maxillary sinuses performed by a single radiologist who was unaware of the CT results. In the patients, who had clinical and radiological signs of sinusitis, a trans-nasal puncture was performed using sinoject (SinoJect, ATOS Medical, Sweden), a spring-activated puncture instrument, to take a sample for microbiologic examination and to drain maxillary sinuses.

RESULTS

Eighty-five percent of the patients were tracheotomised on the fifth day (on average) of their intensive care unit (ICU) stay. The frequency of sinusitis in the study group was found to be 32.5% (13 patients). The most frequently isolated species were Pseudomonas spp. (37.5%), Escherichia coli (20.8%) and Peptostreptococcus (16.7%). Five of the aspirates were polymicrobial. The sensitivity, specificity, positive predictive value and negative predictive value of B-mode US, compared with CT for the detection of fluid presence in maxillary sinuses in a 100 maxillary sinus examinations, were 92.2%, 81.6%, 83.9% and 90.9%, respectively.

CONCLUSION

Maxillary sinusitis should be considered as a source of infection or sepsis in patients with traumatic head injury because of its high frequency. US is likely to be used as the first-line diagnostic tool for the determination of fluid in maxillary sinuses, especially in patients who do not require CT or cannot be transported to a radiology unit for CT.

Ventilator-Associated Pneumonia

The area of the alveolar epithelium of the lung is approximately 70 m². This area is constantly in contact with the ambient air and is therefore vulnerable to contamination with airborne microbes and particles of respirable size. Due to the configuration of the respiratory tract, airborne particles having diameters in the range of 0.5-2.0 μ can reach and deposit in the terminal part of the tracheobronchial tree - most bacteria are of this size. In reality, very few bacteria cause infections by spreading via the airborne route (e.g., mycobacteria, viruses, and legionella). Most bacteria cause pneumonia by first colonizing the upper respiratory tract and later descending into the tracheobronchial tree.

A postural change test improves the prediction of a radiological maxillary sinusitis by ultrasonography in mechanically ventilated patients

OBJECTIVE

The aim of this study was to evaluate a postural change test during sinus ultrasound, compared with CT scan, in case of partial sinusogram to differentiate air-fluid level from mucosal thickening.

DESIGN

Prospective clinical investigation.

SETTING

Medical intensive care unit.

PATIENTS

150 intubated patients.

INTERVENTIONS

Patients were examined by sinus ultrasound in half-sitting position. A partial sinusogram was defined as the sole visualization of the hyperechogenic posterior wall of the sinus. In this situation, a postural change was performed and ultrasound was achieved in supine position. If the partial sinusogram disappeared when the patient was placed in a supine position (positive test), the partial sinusogram was an air-fluid level. If the partial sinusogram did not disappear (negative test), we considered it as a mucosal thickening. The CT and ultrasound were performed on the same day. Radiological maxillary sinusitis (RMS) on CT was defined as the presence of an air-fluid level. Absence of RMS on CT was defined as normal sinus or as the presence of mucosal thickening.

MEASUREMENTS AND RESULTS

300 sinuses were examined. A partial sinusogram was found in 90 sinuses and CT scan confirmed the presence of RMS in 55 sinuses (61%). Sensitivity, specificity, positive predictive value, and negative predictive value of postural change test compared with CT were, respectively, 94.6, 85.6, 91.2 and 90.9%. The positive predictive value increased from 61 to 91.2% after the postural change test.

CONCLUSIONS

In case of a partial sinusogram, a postural change increases the accuracy of ultrasound to diagnose RMS.

Transnasal puncture based on echographic sinusitis evidence in mechanically ventilated patients with suspicion of nosocomial maxillary sinusitis

OBJECTIVE

The aim of this prospective study was to evaluate the value of sinus echography results to directly indicate a transnasal puncture in intubated patients with suspicion of nosocomial maxillary sinusitis.

DESIGN

prospective clinical investigation.

SETTING

medical intensive care unit.

PATIENTS

sixty patients undergoing intubation and mechanical ventilation more than 2 days, with a clinical suspicion of maxillary sinusitis with purulent nasal discharge.

INTERVENTIONS

120 sinuses were examined by sinus ultrasound. The image defined as normal was an acoustic shadow arising from the front wall. Two levels of positive echography were described: (1) a partial sinusogram was defined as the visualization of the hyperechogenic posterior wall of the sinus; and (2) a complete sinusogram was defined as the hyperechogenic visualization of posterior wall and the extension by the internal and external walls of the sinus. When sinus ultrasound was positive, a transnasal puncture was performed the same day. The transnasal puncture was positive if a fluid was obtained from sinus aspiration. The transnasal puncture was negative if there was no aspirated material.

MEASUREMENTS AND RESULTS

sinus ultrasound was positive in 84 cases (54 complete sinusograms and 30 partial sinusograms). Seventy-eight of 84 transnasal punctures were positive. Sensitivity of a sinusogram for obtaining positive transnasal puncture was 100%, and specificity was 86% (100% in case of complete sinusogram) in a clinically selected population. The only six negative transnasal punctures were performed in patients with partial sinusogram.

CONCLUSIONS

Ultrasound sinusitis evidence seems to be of value to indicate and perform a transnasal puncture directly, avoiding CT exam.

Hospital-acquired pneumonia: etiologic considerations

The development of pneumonia requires the pathogen to reach the alveoli and the host defenses to be overwhelmed, either by microorganism virulence or by inoculums size. The endogenous sources of microorganisms are nasal carriers, sinusitis, mouth, oropharynx, gastric, or tracheal colonization, and hematogenous spread. The exogenous sources of microorganisms are biofilm of the tracheal tube, ventilator circuits, nebulizers, and humidifiers. Health care workers may also play a role in this setting. Different microorganisms can be found depending on the onset time of pneumonia and on the local pattern variation encountered between different institutions and countries. Healthy patients may be chronically colonized. A very important, unresolved issue is the definition of early and late-onset pneumonia; it still remains uncertain from the literature whether the given threshold refers to the number of days in hospital or to the number of days following intubation. Noninvasive ventilation is demonstrating that the term "ventilator-associated pneumonia" is perhaps inaccurate and should be referred to as "intubation-associated pneumonia."

Long-term complications of artificial airways

In summary, long-term complications of artificial airways are rare but important sequelae of artificial airways. Many of the potential long-term complications of translaryngeal intubation and tracheotomy are similar and overlapping. Although most patients who undergo these procedures tend to tolerate them without difficulties, significant morbidity and mortality may occur. Identifying the exact cause of the complication may not be possible at times, due to the multiple risk factors involved in the pathogenesis. It is hoped that understanding these potential complications will lead to a more vigilant preventive measures during the institution of long-term artificial airways and a judicious early search for the underlying pathology when a complication is suspected.

Comparison of B-mode ultrasound and computed tomography in the diagnosis of maxillary sinusitis in mechanically ventilated patients

OBJECTIVE

To compare B-mode ultrasound with sinus computed tomograph (CT) scan in the diagnosis of sinusitis in intubated patients undergoing mechanical ventilation.

DESIGN

Prospective, clinical investigation.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

Fifty patients undergoing intubation and mechanical ventilation more than 2 days, with a clinical suspicion of paranasal sinusitis with purulent nasal discharge.

INTERVENTIONS

One hundred paranasal sinuses were examined. A paranasal CT scan and a B-mode ultrasound were performed the same day. Radiologic maxillary sinusitis (RMS) was defined as complete opacification of the sinus or as the presence of an air-fluid level. Absence of RMS was defined as normal sinus or as the presence of mucosal thickening. Important RMS was defined by total opacity or air-fluid level larger than half of the sinus area. Moderate RMS was defined by air-fluid level inferior than half of the sinus area. For ultrasonographic procedure, the image defined as normal was an acoustic shadow arising from the front wall. Two levels of positive echography were described: 1) a moderate lesion was defined as the visualization only of the hyperechogenic posterior wall of the sinus; 2) an important lesion was defined as the hyperechogenic visualization of posterior wall and the extension by the internal wall of the sinus outlining the hypoechogenic sinus cavity.

MEASUREMENTS AND MAIN RESULTS

Sensibility, specificity, positive predictive value, and negative predictive value of B-mode ultrasound compared with CT were, respectively: 100% (95% confidence intervals [95% CI] = 94.9-100.0), 96.7% (95% CI = 82.8-99.9), 98.6% (95% CI = 92.4-99.9), and 100% (95% CI = 88.1-100). The concordance between a moderate B-mode ultrasound lesion and a moderate RMS on CT, and between an important B-mode ultrasound lesion and an important RMS on CT, assessed using kappa statistics was 93%. The concordance between B-mode ultrasound's results and CT's results assessed using weighted kappa statistics was 97%.

CONCLUSION

B-mode ultrasound may be proposed first-line in a ventilated patient with suspicion of maxillary sinusitis.