Thorax 1991;46:601-603

New techniques Series editor: PM A Calverley

Needle aspiration techniques in the diagnosis ofpneumonia

Federico Manresa, Jordi Dorca

There is a need for improved diagnosticmethods in pneumonia in view of the lowbacteriological yield from conventional diag-nostic methods (Gram stain and culture ofbronchial secretions, pleural fluid and bloodculture), the difficulty of identifying the causeof common pulmonary infections on clinicalgrounds, the increasing number of bacteriathat are resistant to commonly used broadspectrum antibiotics (which complicates anempirical approach to treatment), and theclinical importance of correctly identifying thecausative organisms of pulmonary infectionand favourable cost-benefit ratio.'2The aim of needle aspiration is to obtain a

respiratory sample that is not contaminated byoropharyngeal flora, the isolation of theorganisms causing pulmonary infections thusbeing permitted.Of the different needle aspiration techniques

that have been introduced to obtain anaetiological diagnosis of pulmonary infections,only two are considered to be of clinical value,transtracheal needle aspiration and trans-thoracic needle aspiration.

Before any needle aspiration procedurepatients should have their prothrombin timeand platelet count checked. Contraindicationsto needle biopsy are detailed below.

The techniquesTRANSTRACHEAL NEEDLE ASPIRATIONTranstracheal needle aspiration wasintroduced by Pecora in 1959 and modified byKalinske et al.' It is carried out as follows(fig 1):

Servei dePneumologia,Hospital de Bellvitge,University ofBarcelona, 08907L'Hospitalet delLlobregat, Barcelona,SpainF ManresaJ DorcaReprint requests to:Dr Manresa The technique of transtracheal needle aspiration.

The patient is placed in the supine positionwith a cushion beneath his shoulders, so thatthe neck is hyperextended. After the crico-thyroid membrane has been located localanaesthetic (5 ml mevipacaine HCL) isapplied from the skin to the outside of thetrachea. The trachea is punctured (fig 1) by aneedle guiding a venous catheter (Venocath14G, Venisystems Abbott, Sligo, Ireland),with a caudal angle of 45°. The catheter,inside the needle, is then pushed into thetrachea to a distance of at least 10 cm. Oncethe catheter is in the trachea the needle iswithdrawn. During this last procedure thetrachea should be compressed gently for fourminutes to avoid subcutaneous emphysema.

Respiratory secretions are then obtained byaspirating the catheter through a Lukenscontainer. To improve the specificity of thetechnique quantitative or semiquantitativecultures are needed. The instillation of salineinto the trachea is not recommended becauseit will dilute the sample and may thusinterfere with the quantitative assessment.

After withdrawal of the catheter the cervicalregion must be compressed for severalminutes.

TRANSTHORACIC NEEDLE ASPIRATIONTransthoracic needle aspiration (fig 2) is theoldest technique used to determine theaetiology of pulmonary infections. Since 1980ultrathin needles have been used for diagnosticpurposes for pneumonia and neoplasia tominimise the occurrence of pneumothorax.4The pulmonary consolidation must be

located correctly. The patient is then placed inposition to facilitate the introduction of theneedle directly into the lung lesion. Theprocedure is similar to that of a pleural tap andcan be carried out at the bedside.

Local anaesthesia is injected into the chestwall, as for a pleural tap. A large, short guideneedle (fig 2) is passed into the parietal pleura.The ultrathin needle with its inner stylet(15 0 cm long, CookDZLB 25G, William CookEurope, Sandet 6 Bjaeverskov, Denmark) isthen introduced through the large guide needleinto the consolidated lung. The patient isinstructed to breath shallowly, gently, andslowly while the long thin needle is passed intothe lung parenchyma. After removal of thestylet a syringe containing 5 ml saline is con-nected to the needle; 4 ml of saline is injectedinto the lesion and immediately withdrawn,

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Manresa, Dorca

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Figure 2 From left to right: needle, stylet, and large guide needle.

short in-out movements and strong aspiration

being applied for 30 seconds while the needle

remains in place. Part of the injected liquid is

recovered into the syringe, the aspiration is

stopped, and the needle is withdrawn.

With the material retained inside the

ultrathin needle one or several smears are

prepared immediately. The smears and syringe

containing the fluid-should then be sent quickly

to the bacteriology laboratory.The patient should lie down on the side of

the aspiration for 40 minutes after theprocedure. A chest radiograph should becarried out after two hours to check whether apneumothorax has developed.

Diagnostic value and safetyThe diagnostic value of the transtrachealneedle aspiration is remarkably high; its overallsensitivity in bacterial pneumonia andanaerobic pulmonary infections has reached80% in certain series.56 Its specificity isreported to be low in some circumstances,however, about 22% of patients with lungcancer and 40% of patients with chronicbronchitis (frequent hosts oforganisms causingbacterial pneumonia) having false positiveresults due to contamination of the bronchialtree.78 These figures are even higher in patientswith gastric aspiration or in coma.9

Complications from this technique are rare,the most important being subcutaneoushaemorrhage and emphysema, which occur inless than 10% of cases. Vagal reactions, cervicalcellulitis, angina pectoris, and spasm of theglottis have been reported.'0

Transtracheal aspiration is not very accept-able to patients and other procedures(protected bronchoscopic specimen brushingand transthoracic needle aspiration) arereplacing it. The number of series in whichthis technique has been used has declinedsubstantially in the last five years."The sensitivity of transthoracic needle

aspiration has varied from 60% to 90%,depending on the type of infection. Severalauthors have found the specificity to be almost100%, and for practical purposes the organismisolated after Gram staining or culture ofa transthoracic needle aspirate (excludingcutaneous contaminants such as coagulasenegative staphylococci etc) is considered to beresponsible for the pneumonia.4 12-14With the use of ultrathin needles the

complication rate of this technique is extremelylow. In our experience of more than 300procedures only 1-2% of patients have hadcomplications that required treatment (pneu-mothorax or haemoptysis).'2 Patients' accept-ance ofthe procedure is good and similar to thatof a thoracocentesis.The training required to perform any of

these aspiration techniques correctly is verysimple. The low incidence of complicationsmay be attributed to adequate training, thesimplicity of the procedure, and the type ofneedle used.

Indications and contraindicationsThe two needle techniques have identicalindications but, as mentioned earlier, trans-thoracic needle aspiration (and use of thebronchoscope protected specimen brush) willprobably replace transtracheal aspiration forthe diagnosis of pulmonary infections inpatients breathing spontaneously.

In our experience transthoracic aspirationcomplements conventional methods of inves-tigation (Gram staining ofbronchial secretions,blood culture, etc), and we consider its use inthe following clinical settings:1 hospital acquired pulmonary infections innon-ventilated patients;2 community acquired pneumonia that maybe caused by an uncommon pathogen (in old

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Needle aspiration techniques in the diagnosis ofpneumonia

age, chronic debilitating diseases, immuno-suppression, etc);3 pneumonia that fails to respond toappropriate empirical treatment;4 lung abscesses not responding to apparentlyappropriate empirical treatment.The principal contraindications for the

needle techniques are coagulation disturban-ces: thrombocytopenia (the lowest acceptableplatelet count is 100 000/ml and a prothrombintime of 60%. Other contraindications areuntreatable cough, very poor lung function(FEV1 below 1-0 1), and the presence of bullae.We do not recommend the use of trans-

thoracic needle aspiration in patients under-going assisted ventilation.

1 Research Committee of the British Thoracic Society and thePublic Health Laboratory Service. Community acquiredpneumonia in adults in British hospitals in 1982-83: asurvey of aetiology, mortality, prognostic factors andoutcome. Q J Med 1987;239:195-200.

2 Dorca J, Rufi G, Verdaguer R, et al. Therapeutical relevanceof the transthoracic aspiration with ultrathin needle inbacterial lung infections [abstract]. Am Rev Respir Dis1990;141:A861.

3 Kalinske R, Parker R, Bandt D, Hoeprich P. Diagnosticusefulness and safety of transtracheal aspiration. N Engl JMed 1967;276:604-8.

4 Zavala DC, Schoell JE. Ultrathin needle aspiration of thelung in infectious and malignant diseases. Am Rev RespirDis 1981;123:125-31.

5 Irvin R, Pratter M. Transtracheal aspiration procedure: aprotocol. Chest 1981;79:245-7.

6 Ries K, Levison M, Kaye D. Transtracheal aspiration inpulmonary infection. Arch Intern Med 1974;133:453-8.

7 Bjerkestrand G, Digranes A, Achreiner A. Bacteriologicalfindings in transtracheal aspirates from patients withchronic bronchitis and bronchiectasis. Scand J Respir Dis1975;56:201-7.

8 Fossieck B, Parker RH, Cohen MH, Kane RC. Fiberopticbronchoscopy and culture from the lower respiratorytract. Chest 1977;72:5-9.

9 Bartlett JG, Rosenblatt J, Finegold S. Percutaneoustranstracheal aspiration in the diagnosis of anaerobicpulmonary infection. Ann Intern Med 1973;79:535-58.

10 Irwin R, Pratter M. Transtracheal aspiration guidelines foryour safety. Chest 1979;76:518-20.

11 Manresa F. Rapid clinical diagnostic methods in respiratoryinfections. Current Opinion Infect Dis 1989;2:536-40.

12 Dorca J, Boada J, Verdaguer R, et al. The transthoracicaspiration with ultrathin needle in the diagnosis of bac-terial pulmonary infection [abstract]. Eur Respir J1988;1(suppl 2):264S.

13 Palmer DL, Davidson M, Lusk R. Needle aspiration of thelung in complex pneumonia. Chest 1980;78:16-21.

14 Castellino RA, Blank N. Etiologic diagnosis of focalpulmonary infection in immunocompromised patients byfluoroscopically guided percutaneous needle aspiration.Radiology 1979;132:563-7.

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