Percutaneous Drainage of Abscess and Post Operative Collections

Percutaneous Drainage Of Collections and Abscess

Dr.Suhas Basavaiah

Resident (MD Radio-Diagnosis)

INTRODUCTIONPercutaneous abscess drainage (PAD) has evolved from revolutionary

to routine, replacing open surgical abscess drainage in all but the most difficult or inaccessible cases.

Originally only patients with simple fluid collections were candidates for PAD; however, researchers have convincingly demonstrated that both septated and viscous fluid collections may be successfully treated percutaneously, particularly with the adjunctive use of lytic agents.

An aggressive practical approach with relatively simple devices and techniques may yield a high success rate with few complications.

Marked growth in last 20 years

All types of simple and complex collections drained in the chest,abdomen and pelvis

Requires ability to assess CT and US images and familiarity with drainage equipment

Collection Assessment-Imaging

Aim - shortest, safest route to site drain in the most dependent position

Avoid major vessels

Avoid transgressing bowel

Assessment of nature of fluid-echogenicity ; septations

IMAGING – US or CT

CT

good visualisation

opacified bowel

not limited by ileus or depth

US

real time

portable

operator dependent

Size+site of collection ; operator preference

Ultrasound guided percutaneous drainage is one form of image guided procedure, allowing minimally invasive treatment of collections that are accessible by ultrasound study.

It has several advantages and disadvantages over CT, which include:

Advantages

is a dynamic study, allowing greater precision to control needle insertion

not exposes patient to ionising radiation

does not require as wide a range of staff, compared to CT-guided procedures

Disadvantages

deeper targets may not be as well visualised on ultrasound (e.g. retroperitoneal nodes)

bowel gas may obscure visualization

attenuation of the sound beam on larger patients

IndicationsIndications for percutaneous drainage are broad: essentially any abnormal fluid collection in the patient which can be accessible. Examples include:

complicated diverticular abscess

Crohn disease related abscess

complicated appendicitis with appendicular abscess

tuboovarian abscess

post-surgical fluid collections

hepatic abscess (e.g. amebic or post-operative)

renal abscess or retroperitoneal abscess.

splenic abscess

Contraindications

The only common contraindications are:

biopsy target is not accessible

patient has a bleeding diathesis

Laboratory parameters for a safe procedureInterventional procedures like percutaneous drainage require special attention to coagulation indices. There are widely divergent opinions about the safe values of these indices for percutaneous biopsies. The values suggested below were considered based on a literature review.

Complete blood count: Platelet > 50000/mm3 (Some institutions determine other values between 50000-100000/mm3)

Coagulation profile:

international normalized ratio (INR) ≤1.5 1

normal prothrombin time (PT), partial thromboplastin time (PTT)

Some studies show that having a normal INR or prothrombin time is no reassurance that the patient will not bleed after the procedure

Pre-procedure evaluation

Review other diagnostic studies first to clarify the collection that is requested to be drained.

An ultrasound study should be done prior to biopsy to decide the access angle and check the relationship of the collection to adjacent structures.

In general, the shortest possible route is preferred, as long as it does not traversing other structures.

EquipmentNeedle

Typical abscess fluid is readily aspirated through an 18-gauge needle

Viscous or debris-laden fluid is more likely to cause a false-negative aspirate with a 21-gauge needle as only clear supernatant may return through the needle.

An 18-gauge needle is easier to control and image and accepts a 0.038-inch guidewire.

There is no clinically significant difference in needle trauma between the 18 and 22-gauge needles when a catheter is placed through the same tract.

The 21-gauge needle may be used to minimize trauma for a challenging localization, low-probability fluid collection, or personal preference.

Equipment (contd.)

Catheters

6F-24F catheters

Locking or non-locking-VIP at removal

Sump or non-sump-2nd lumen containing air which prevents cavity collapsing around catheter tip

Guidewire

A variety of guidewires are available for PAD with different properties and prices. Guidewires should meet the following specifications:

Stiff enough to guide dilators and catheter into abscess

Not too stiff to prevent easy coiling of wire shaft within abscess

Floppy tipped enough to encourage wire to coil within the abscess and not perforate the abscess wall

Short enough to make use convenient

Localization Techniques Any modality may be used to assist needle placement.

Prior to ready availability of CT fluoroscopy, patient assessment may be performed with CT scanning, with the PAD procedure performed with US localization.

Conventional fluoroscopy can be used as an adjunct to US.

US guidance allows real-time imaging and does not involve radiation exposure.

CT fluoroscopy is increasingly available and facilitates "one-stop-shopping."

The diagnostic CT and PAD may now be performed readily in one setting.

PATIENT PREPARATION

IV access

Fasted for > 2 hours

Coagulopathy excluded

Informed consent

PROCEDURE

Ultrasound guided percutaenous drainage may be performed with a single or multiple stage technique.

Consider conscious sedation

Clean skin

Anaesthetise skin

Skin incision large enough for passage of catheter

Consider tract dissection

TROCAR TECHNIQUE

Reference needle in collection

Catheter assembly advanced to the same depth ,in the same plane

Remove stylet and aspirate

Advance catheter over stationary stiffener

SELDINGER TECHNIQUE

18g needle in collection

Pass 0.035 wire into collection

Dilate tract

Pass catheter and stiffener over wire

When inside collection pass catheter alone

POST-INSERTION OF DRAIN

Aspirate fluid

Re-image:?need for 2nd drain

Secure drain-it is always more difficult to re-puncture a partially drained collection

POST-PROCEDURE CAREPost-procedure care The patient's basic vital signs should be monitored for 4 hours post

procedure (pulse, blood pressure, SpO2), or as long as deemed necessary.

Aspirate 8hrly with a 50ml. Syringe

Irrigate with 10ml. of saline

Dependent position of bag

The patient should remain in bed for 2 hours. After this time period mobilization and oral intake is permitted.

Removal-clinical improvement and drainage of <10ml. per day or collection resolved on re-imaging

The entry site should be reviewed on a daily basis. If output from the collection ceases, it may mean that the collection is no longer present or that the drain is clogged.

TIPS - INSERTION

Ensure adequate skin incision

Avoid kinking wire(no fluoroscopy)

Ideal wire-stiff enough to allow passage of dilators and catheter but will coil within abscess and not perforate posterior wall

Cut thread flush with catheter hub

3-way tap

IF COLLECTION PERSISTS WITH LOW FLOWS

Catheter displacement

Catheter/tubing blocked or kinked

Upsizing catheter

Septation/loculation

If Collection Persists with high flows

Expect to find a fistula

Can occur from bowel, bile and pancreatic duct, renal tract

Exclude distal obstruction ; underlying bowel disease ; proximal diversion ; parenteral feeding

Bile leak postlap.chole.- drain plus cbd stent

IF THERE IS PRESENCE OF GROSS BLOOD

Place the catheter

Let the blood drain into the bag

Since blood is a potent irritant and toxic to omentum, it has to be drained regardless to avoid fatal complications like peritonitis and adhesions

COMPLICATIONS

Viscus perforation

Catheter dislodgement

Damage to vessels

Peritonitis

Diaphragm rupture

MINIMIZING COMPLICATIONS

Broad spectrum antibiotics

Correct coagulopathy

Adequate sedation + analgesia-beware the restless patient

Good bowel opacification at CT

Post procedure catheter management

Beware collections adjacent to implants-aspirate>drain

Discuss cases with clinical team

PITFALLS

The procedure was not indicated.

Failure to obtain informed consent

Failure to perform the procedure in a reasonable manner and deviation from the standard of care.

Failure to promptly recognize and react to a complication.

Failure to adequately treat the complication according to an adequate standard of care.

CONCLUSION

Assess pre-procedure imaging

Minimise complications related to PAD

Involvement in post procedure catheter management

Practical knowledge of needles, wires and catheters

References

Emedicine , percutaneous drainage of abscess and post operative collections

Radiopedia , USG guided percutaneous drainage

American College of Radiology. Percutaneous catheter drainage of infected intra-abdominal fluid collections

Haaga JR, Weinstein AJ. CT-guided percutaneous aspiration and drainage of abscesses.

Lang EK, Springer RM, Giorioso LW, Cammarata CA. Abdominal abscess drainage under radiologic guidance: causes of failure.

Thank You