The "lung point": an ultrasound sign specific to pneumothorax

Objective: We studied an ultrasound sign, the fleeting appearance of a lung pattern (lung sliding or pathologic comet-tail artifacts) replacing a pneu mothorax pattern (absent lung sliding plus exclusive horizontal lines) in a particular location of the chest wall. This sign was called the "lung poin t". Design: Prospective study. Setting: The medical ICU of a university-aff iliated teaching hospital. Patients: The "lung point" was sought in 66 cons ecutive cases of proven pneumothorax analyzable using ultrasound - includin g 8 radio-occult cases diagnosed by means of CT and in 233 consecutive hemi thoraces studied by CT and free of pneumothorax - including 17 cases where pneumothorax was suspected. Results: The "lung point" was observed in 44 of 66 cases of pneumothorax (including 6 of 8 radio-occult cases) and in no c ase in the control group. The location of this sign roughly correlated with the radiological size of the pneumothorax. The "lung point" therefore had an overall sensitivity of 66 % (75 % in the case of radio-occult pneumothor ax alone) and a specificity of 100 %. Conclusion: The presence of a "lung p oint" allows positive diagnosis of pneumothorax at the bedside using ultras ound.