Radiologically-guided percutaneous catheter drainage of empyemas

ClinicalRadiology (1988)39, 121-126

Radiologically-guided Percutaneous Catheter Drainage of Empyemas G. R. H U N N A M and C. D. R. F L O W E R

Department of Radiology, Addenbrooke's Hospital, Cambridge

We describe our experience with the percutaneous drainage of empyemas in 20 patients, using fluoroscopic, computed tomographic or ultrasonic guidance for catheter placement. The patients were seen over a period of 17 months. Sixteen patients were successfully treated, with the empyema drained and the cavity closed. In four patients drainage was unsuccessful and surgery was required. In three of these patients there was a history of illness in excess of 4 weeks preceding treatment and in one a history of trauma. Two or more catheters were used in seven patients and positive microbiological culture of the pus was obtained in 12, although neither factor significantly altered prognosis. There were no complications of the procedure. We believe the percutaneous insertion of catheters using suitable imaging guidance should be the initial method of drainage of empyemas.

The treatment of empyema thoracis depends on adequate drainage. This is usually accomplished by repeated needle aspiration or closed tube drainage (Alexander and Wolfe, 1980). Surgery, either decortication or local rib resection, is required if closed drainage fails. Incomplete evacuation of pus is more likely to occur following repeated needle aspirations than with intercostal tube drainage (Benfield, 1981). Malposition of intercostal tubes inevitably results in inadequate drainage (Stark et al., 1983a) and may cause major complications, such as chest wall haematoma, pulmonary laceration and infarction, and trauma to the liver, spleen or stomach (Milliken et al., 1980). As a result, fluoroscopy (Westcott, 1985), ultrasound and computed tomography (van Sonnenberg et al., 1984) have been suggested as suitable imaging techniques for securing adequate and safe placement of percutaneous catheters for closed drainage of empyemas. We have employed radiologically-guided drainage for empyemas, either when conventional chest drainage has proved inadequate or when imaging was required for loculated collections of pus. This report reviews the technique and results of radiologicallyguided percutaneous catheter drainage at this hospital and discusses its role in the management of patients with empyema. PATIENTS AND M E T H O D S Between March 1985 and August 1986, twenty patients underwent drainage of empyema using Correspondence: Dr G. R. Hunnam, Department of Radiology, Addenbrooke's Hospital, Cambridge.

radiologically-guided catheters. The average age of the 15 men and five women was 55 years (range 8 to 89 years). All were receiving treatment with antibiotics at the time of the procedure. Three were referred because of inadequate drainage consequent upon malposition of an intercostal Argyle chest drain (Fig. 1), and three because of the development of an empyema following thoracotomy. The remaining 14 patients underwent radiologically-guided drainage as the initial diagnostic and therapeutic procedure. Postero-anterior and lateral chest radiographs were performed on all patients following which ultrasound or computed tomography were performed to assess further the location and extent of the pleural collection of pus before drainage. A combination of fluoroscopy, ultrasound or computed tomography was used to guide the initial placing of the cannula (Table 1). In general, computed tomography was preferred for small loculated abscesses or when the empyema could not be localised reliably by ultrasound. The procedure was performed with the patient in whatever position allowed best access to the empyema. The cannula was placed near the centre of the collection of pus although with large empyemas the most dependent point was selected. In all cases care was taken to avoid the neurovascular bundle beneath the adjacent rib. Initial puncture of the empyema was performed with a 14G teflon sheath-needle cannula (Wallace Flexihub cannula, H. G. Wallace Ltd, Colchester) (Fig. 2b) and samples obtained for gram-staining and culture, both aerobic and anaerobic (Bartlett and Finegold, 1974). Catheter insertion can be painful and in addition to local anaesthesia (1% lignocaine) it was usually found advisable to use an intravenous analgesic such as pethidine or morphia. One patient, aged 8, required general anaesthesia. Catheters were then introduced over a 0.038in J-tip teflon guide-wire passed through the sheath into the pleural space following the enlargement of the track with appropriate dilators (Fig. 2c). Whenever possible, a relatively long length of catheter was inserted for stability and to maximise drainage. With small collections of pus, care was taken to ensure that none of the side-holes of the catheter were located outside the pleural space. Following placing the catheter, as much pus as possible was aspirated, up to 1000ml, following which either chest radiography or computed tomography was performed (Fig. 2d). On three occasions fluoroscopy was performed to verify that the best position for adequate drainage had been achieved (Fig. 3). If there was evidence of untapped collections of fluid further catheters were inserted into the loculi (Fig. 4). The catheters were connected to an underwater seal and suction applied (approximately 20cm water negative pressure via a Roberts pump). The catheter was irrigated with 100 ml of normal saline

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(b)

(a)

Fig. 1 - (a) A portable antero-posterior radiograph suggests satisfactory placement of the left chest drain (black arrow). Computed tomography at two levels (b and c) reveals malposition of the chest drain (white arrow) which lies anterior to the empyema.

Table 1 - Method for Iocalisation of empyemas and guidance of catheters

No. of patients Ultrasound alone Computed tomography alone Ultrasound and computed tomography Ultrasound and fluoroscopy Fluoroscopy Total

8 5 4 2 1 20

every 6h, both to maintain patency and to break up fibrous adhesions, thereby aiding drainage. The catheters were left in situ until there was clinical and radiological evidence of complete drainage. On average this was for 9 days (range 2 days to 6 weeks). Either a 10F Cook Cope loop (William Cook, Europe) or Van-tec (Lewis Medical, London) pigtail catheter were used in 16 patients. The Cook Cope catheters were better tolerated probably because of their greater flexibility, but were more expensive than the Van-tec catheters. In five patients 14G Bonanno catheters (Becton-Dickinson) with central trocars were introduced directly through the track formed by the sheath-needle cannula and these had the advantage of shortening the duration of the procedures, though the catheters drained less well over several days probably because the plastic structure allowed buckling.

(c)

RESULTS

Sixteen patients were successfully treated, with complete closure of the empyema cavities. Two of these 16 patients died later after satisfactory drainage, one from retroperitoneal haemorrhage due to warfarin therapy and one following a fractured neck of femur. The remaining 14 patients have been followed up for between 4 and 18 months with no evidence of recurrence of empyema. In four patients catheter drainage did not result in resolution of the empyema. All required surgery, with evacuation of pus and decortication of the lung in three, and with the evacuation of thick pink gelatinous material consisting of fibrin and protein in one patient. A preceding history of illness exceeded 4 weeks in four patients (Table 2), three of whom had unsuccessful catheter drainage. As indicated in Table 3, slightly better results were obtained for post-pneumonic empyemas, compared with post-surgical empyemas (gastro-intestinal, cardiothoracic and maxillary antral surgery), whilst failure in one patient with an infected haematoma following trauma was in keeping with the results of other series (Bryant et al., 1968). A total of thirty catheters were used in twenty patients, with 13 patients requiring one catheter only and a further seven requiring two or three catheters, either because of multiple loculi of fluid or because of recurrent fluid collections after apparently satisfactory

DRAINAGE OF EMPYEMAS

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(a)

(d)

(b)

(c) Fig. 2 - (a) Computed tomography at the level of the aortic arch demonstrates a right sided fluid collection with an air fluid level suggestive of an empyema with a bronchopleural fistula. The patient had had a right pneumonectomy several years previously for a vascular anomaly and now presented with symptoms suggestive of an empyema. (b) Computed tomography at the same level in the prone position showing satisfactory placement of the 14G sheathneedle cannula. (c) Following exchange, the pigtail catheter is satisfactorily located in the empyema cavity (d) The final satisfactory position is confirmed on the plain radiograph.

Fig. 3 - Satisfactory initial aspiration of pus and placement of the pigtail catheter was confirmed by fluoroscopy.

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(c)

(d)

Fig. 4 - (a) Computed tomography demonstrates a multiloculated right pleural collection of fluid. (b) A chest radiograph of the same patient following insertion of the two intercostal drains. (c and d) Computed tomography at the sites of tube insertion confirms complete resolution of the pleural collections of fluid.

(b)

Table 2 - Effect of length of history p r e c e d i n g d r a i n a g e on o u t c o m e

Table 3 - Influence of aetiology of e m p y e m a on successful d r a i n a g e

Aetiology

Length of h&tory

Drainage successful unsuccessful Total

Less than 4 weeks (no. of patients)

More than 4 weeks (no. of patients)

15 1 16

1 3 4

initial drainage. Whilst the use of a single catheter was associated with greatest success, this was not always so (Table 4). Recurrent fluid collections occurred in four patients, in w h o m the initial catheter was removed when it was felt successful drainage had occurred on

Drainage successful unsuccessful Total

Postsurgical (no. of patients)

Postpneumonic (no. of patients')

Posttraumatic (no. of patients)

6 2 8

10 1 11

0 1 1

clinical and radiological grounds. Further catheter placement resulted in successful drainage in two of these patients, but the other two subsequently required surgery. These four patients were amongst the

DRAINAGE OF EMPYEMAS

Table 4 - Relationship between number of catheters used and successful drainage

Number of catheters used

Drainage successful unsuccessful Total

1 (no. of patients)

2 or3 (no. of patients)

11 2 13

5 2 7

Table 5 - Bacteriological results. No organism was isolated from 8 (40%) of patients (all patients on treatment with antibiotics prior to drainage)

Organism

No. of positive cultures (12 patients)

Staphylococcus aureus

% of total

Anaerobic streptococcus

4* 3*

16 12

Eschericheae coli

2

8

Klebsiella species

2*

8

Streptococcus milleri

2

8

P s e u d o m o n a s species

1

4

Haemophilus influenzae

1

4

15

60

Total

125

correct tube placement particularly when collections of pus are multi-loculated or in relatively inaccessible positions. In addition, radiological imaging, particularly with computed tomography, provides additional diagnostic information (Stark et al., 1983a). In three of our patients, malposition of the original chest drain was confirmed and in one an unsuspected hepatic haematoma due to previous incorrect tube insertion (Fig. 5) was diagnosed. A bronchopleural fistula not apparent on the chest radiograph was demonstrated in another patient (Fig. 2a) as was an underlying lung abscess, not suspected clinically or seen on plain chest radiographs (Fig. 6). Empyemas and lung abcesses are sometimes distinguished with difficulty and computed tomography has an important role in this respect (Stark et al., 1983b).

* More than one organism cultured from a single patient

Table 6 - Relationship between culture and drainage

Culture

Drainage successful unsuccessful Total

Positive (no. of patients)

Negative (no. of patients)

9 3 12

7 1 8

earlier seen in our series and with this experience we subsequently continued drainage for a longer period. Pus cells were present on microscopy in all patients and the total amount of pus drained per patient varied from 30 to 4000ml (average 775ml). Culture of the pus produced growth of micro-organisms in 12 patients, pre-treatment with antibiotics probably accounting for the failure to obtain a growth in the remaining eight patients. A large range of organisms were isolated (Table 5). Slightly better results of drainage were obtained in those patients in whom culture failed to reveal an underlying organism (Table 6). No major complications occurred in the 20 patients, although chest pain related to the catheter and requiring simple analgesia occurred in almost all patients, particularly towards the end of drainage as the pleural layers opposed.

DISCUSSION Our results confirm the previous reports (van Sonnenberg et al., 1984; Westcott, 1985) that radiologically-guided drainage using relatively fine bore catheters can be employed successfully as an alternative to standard chest drainage. This technique ensures adequate bacteriological sampling of the fluid and

Fig. 5 - C o m p u t e d t o m o g r a p h y through the liver reveals a haematom a within the right lobe of the liver, following previous unsuccessful tube insertion.

Potential disadvantages of our technique include kinking of the catheters due to their flexibility and occlusion by thick pus and debris due to their relative narrow calibre. To maintain patency of the catheters, regular irrigations are required using a similar method to that described for abdominal abscesses (van Sonnenberg et al., 1982). Most empyemas are of low viscosity, especially during the early exudative and fibrinopurulent stages (American Thoracic Society, 1962), and can then be aspirated easily via small catheters. As the cellular content increases, with the formation of thick pus and pleural fibrous thickening, tube drainage is less successful, particularly when the preceding history exceeds 4 weeks (Benfield, 1981). Exchanging the catheter for a larger chest drain is unlikely to be successful and surgery is usually required. Whilst greatest success is achieved in the postpneumonic empyemas, many para-pneumonic effusions resolve without requiring tube drainage of the pleural space (Light, 1976). However, this is not inevitable and it is impossible to predict. If tube drainage is required but is delayed, the patient's hospital course is prolonged, several chest tubes may have to be inserted because of the loculation and the patient may eventually require decortication. Since

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(a)

after a few days of adequate antibiotic therapy and where the presence of pus cells within the fluid is confirmed. Effective drainage of these infected pleural effusions results in a dramatic reduction in the patient's temperature, often within a few hours, with considerable symptomatic improvement. This series confirms that radiologically-guided catheters can be successfully used to treat patients with empyemas. The use of ultrasound or computed tomography permits accurate and safe placement of the catheters, which, although of relatively small calibre, permit adequate drainage in the majority of patients. Since this small series we have had a marked increase in the number of patients referred for radiologically-guided catheter drainage and the results continue to be encouraging. We consider that it should be the method of choice for the initial drainage of empyemas.

Acknowledgements. We thank the various colleagues who referred patients for this procedure and in particula r Drs J. Stark, T. Higenbottam, J. Shneerson and Mr F. Wells, who have offered us their advice and encouragement. We thank Alison Emery who kindly typed the manuscript. The Addenbrooke's Hospital Department of Medical Illustration and Photography prepared the photographic prints.

REFERENCES

(b) Fig. 6 - Computed tomography (a) through the lower thorax reveals a large right lower lobe abscess, not suspected on the chest radiographs, in addition to the large pleural abscess. (b) Computed tomography in the left lateral decubitus position confirms the location of the right lower lobe abscess, as well as demonstrating consolidation within the right middle lobe.

drainage is more successful during the early exudative and fibrinopurulent stages of an empyema it seems reasonable to perform it at the earliest possible stage. The decision to drain such collections of fluid requires close liaison with clinical colleagues. Our policy has been to drain such effusions where there has been no significant clinical response, either in the patient's symptoms or temperature, or in size of the effusion,

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