Pleural pressure(PIP) is the balance between outward pull of thoracic cavity and inward pull of the lung. Light et al and others have reported the measurement of PIP during therapeutic thoracentesis(TT).1 Vilhena et al tried to ascertain whether PIP measurement provides any clue to the etiology of the effusion.2 We report the technique of measurement of PIP during TT to rule out trapped lung in a 49-year-old male with hepatitis B, cirrhosis and portal hypertension, who presented with recurrent pleural effusion. To our knowledge the technique that we used has not been previousely described in the literatureCASE REPORT: A 49-year-old male with history of hepatitis B for 3 years, cirrhosis, hypertension, chronic renal insufficiency, GI bleed was referred to us with increasing dyspnea, decreased exercise tolerance and orthopnea. Similar symptoms 2 months ago had revealed a large Right-sided pleural effusion with collapse of the right lung (Fig 1
Before Thoracentesis). He was a painter with a 1 pack-year smoking history and a family history of lung cancer. Repeated TT yielded large amounts of transudative pleural effusion which rapidly reaccumulated. No significant improvement was noted with furosemide and spironolactone. Abdominal ultrasonograhy revealed no ascites. Bronchoscopy did not reveal any endobronchial lesion. Refractory hepatic hydrothorax without ascites and trapped lung were the diagnoses entertained. Pleural thickening was difficult to assess on chest CT done immeditely after TT, because of rapid reaccumulation of fluid.. Therefore it was decided to measure PIP to rule out trapped lung.The procedure was performed in ICU with the patient sitting upright A “Kendall” thoracentesis system with an angiocath catheter “BD insyte-autoguard” 16G, 1.7 inch was used to perform the TT. This was connected to an A line transducer which in turn was connected to the “Space lab” monitor (scale 30). Zero value was set at the thoracic puncture level. PlP was measured before removing any fluid, after the removal of every 100 ml for the first 500 ml, then after the withdrawal of every 500 ml for the second liter. A total of 2000ml of fluid was aspirated. The mean of the Inspiratory and expiratory PIP values was calculated. Clinical signs and symptoms (chest pain, cough, and chest tightness) were watched for. The pressures obtained are seen in Table 1
Pleural pressureVolume Aspirated (ml)End Exp. Pressure (cm H2O)End Insp. Pressure (cm H2O)0+3-5100+3-5200+3-5300+3-5400+5-3500+1-510000-715000-102000-3-13.The initial PIP at the onset of the procedure was -1cm H2O; -3cm H2O after withdrawal of the first liter and -8cm H2O at the end of 2 liters. These readings did not meet the criteria for the diagnosis of trapped lung.DISCUSSION: PIP can be measured directly (using needles, trocars, catheters, balloons) or indirectly (by positioning a balloon / micromanometer in the esophagus).In trapped lung a fibrous peel may form over the visceral pleura in response to pleural inflammation and prevent underlying lung from expanding. It can be diagnosed when the initial PIP during TT is below -10cm H2O and PIP falls more than 20 cm H2O per 1000ml as fluid is removed.In our patient the initial pressure was around -2cm H2O and dropped by less than 20cm H2O after removal of each 1000 ml ruling out Trapped lung
PIP measurement can be easily performed at the bedside during thoracentesis and can be an important tool to assisst in the diagnosis of pleural effusion
After Multiple Thoracenteses
V.E. Coelho-D’Costa, None.