Insertion of pleuro-amniotic shunt for fetal pleural effusion (interventional procedure consultation document)
NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE
Interventional Procedure Consultation Document
Insertion of pleuro-amniotic shunt to drain fetal pleural effusion
Fetal pleural effusion is the abnormal build-up of fluid in the chest of an unborn baby, which can cause pressure on the lungs and heart. A pleuro-amniotic shunt is a tube inserted between the chest and the amniotic cavity while the baby is still in the womb, to drain the excess fluid from the chest.
The National Institute for Health and Clinical Excellence is examining insertion of pleuro-amniotic shunt to drain fetal pleural effusion and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about insertion of pleuro-amniotic shunt to drain fetal pleural effusion.
Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.
The process that the Institute will follow after the consultation period ends is as follows.
For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).
Closing date for comments: 27 June 2006
Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.
Current evidence on the safety and efficacy of pleuro-amniotic shunts to drain fetal pleural effusions appears adequate. However, there are uncertainties about the natural history of fetal pleural effusion and about patient selection. Therefore, this procedure should not be used without special arrangements for consent and for audit or research.
Clinicians wishing to undertake insertion of pleuro-amniotic shunt for fetal pleural effusion should take the following actions.
|1.3||This procedure should only be performed in centres specialising in invasive fetal medicine and in the context of a multidisciplinary team, which should include a consultant in fetal medicine, a neonatologist and a specialist midwife.|
|1.4||Further evidence on case selection will be useful. The Institute may review the procedure upon publication of further evidence.|
|2.1.1||A fetal pleural effusion can be associated with many different conditions such as chromosomal abnormalities, congenital malformations, chylothorax, anaemia, heart defects, cardiac arrhythmias and viral infections. Some pleural effusions resolve spontaneously before birth.|
|2.1.2||The major complication of a large persistent pleural effusion is prevention of normal lung growth and development. When an effusion progresses in size, it can cause caval compression, leading to hydrops fetalis, which can result in fetal death. Lung compression associated with the effusion can cause pulmonary hypoplasia, which in turn greatly increases the risk of death from respiratory failure soon after birth. The major factors that determine postnatal survival are the underlying aetiology of the pleural effusion, whether delivery is preterm and whether pulmonary hypoplasia or hydrops fetalis are present.|
|2.1.3||Prenatal interventions include thoracocentesis and drainage of the effusion in an attempt to allow normal lung development and prevent hydrops fetalis. In some cases, the fluid re-accumulates, requiring repeated procedures. Postnatally, if the effusion (with or without pulmonary hypoplasia) causes respiratory compromise, immediate drainage and intensive respiratory support are required.|
Initial treatment of a pleural effusion involves needle aspiration of the fluid from the fetal chest cavity; frequently either an amniocentesis will be performed or fetal blood sample will be obtained at the same time to help establish underlying aetiology. If re-accumulation of fluid is noted on repeat scans, pleuro-amniotic shunting may be considered.
|2.2||Outline of the procedure|
|2.2.1||The procedure involves insertion of a drainage tube though the fetal chest wall into the pleural space, allowing drainage of fluid into the amniotic cavity. Different types of drainage tubes may be used.|
Under maternal ultrasound guidance and using local anesthesia, a metal cannula on a trochar is introduced though the mother's abdominal and uterine walls into the amniotic cavity and is then inserted through the fetal chest wall, into the effusion in the pleural cavity. The trochar is then removed and the drainage catheter inserted into the cannula and placed with one end in the pleural cavity and the other in the amniotic cavity. The cannula is then removed and the final position confirmed by ultrasound. The success of the procedure is determined by serial ultrasound scans, to monitor resolution of the effusion, absence or resolution of hydrops fetalis and lung growth. If the effusion re-accumulates, another shunt may be inserted. After delivery, the shunt tube is immediately clamped and removed to prevent the development of pneumothorax.
In one case series, effective drainage and lung expansion was achieved in 98% (46/47) of fetuses treated with pleuro-amniotic shunt. This produced resolution (where present) of polyhydramnios (excessive accumulation of amniotic fluid) in 67% (20/30) and of hydrops fetalis in 46% (13/28) of fetuses.
|2.3.2||Postnatal respiratory morbidity did not occur in any infant included in two case series (n = 47 and n = 21) at follow-up of between 2 months and 6 years. Another case series reported that none of 17 infants had respiratory symptoms at the time of final follow-up, although 35% (6/17) did have respiratory problems at some stage of postnatal development, requiring either bronchodilator or antibiotic medication.|
|2.3.3||Survival beyond the neonatal period following the insertion of a shunt to drain a pleural effusion was reported across case series to be 48% (10/21), 58% (28/48), 66% (29/44), 67% (6/9) and 100% (3/3), although the severity of the effusion and underlying pathology varied across the studies. In two case series, survival of fetuses with pleural effusions not associated with hydrops fetalis was 60% (3/5) and 100% (15/15).|
One study found that re-accumulation of the pleural effusion required a new shunt to be inserted in 8% (4/49) of fetuses. In another series, repeat shunt placement was required in 33% (3/9) of fetuses, and in a third series re-accumulation of pleural effusion occurred in 6% (1/17) of fetuses, attributed to removal of the shunt by the fetus. For more details, refer to the sources of evidence (see appendix).
The Specialist Advisors commented that, in some instances, a fetal pleural effusion may resolve spontaneously, and there has to be a balance between treatment and natural progression of the effusion. They also commented that treatment outcomes may be related to case selection, and that indications for the procedure are not yet well established.
|2.4.1||Only one study (n = 13) provided details about intra-operative complications. In one fetus with bilateral effusions, a traumatic haemothorax occurred during insertion of a second shunt.|
|2.4.2||The most commonly reported complications arose during the gestational period following insertion of a shunt. In one case series, 1 of 10 fetuses died as a result of shunt complications; in another study, 1 of 9 fetuses died as a result of shunt insertion complication. Unilateral arm oedema in a fetus was also reported in a series of 10 cases.|
Displacement of the shunt into the thorax was reported in 23% (3/13) of fetuses at three separate centres within one case series. However, this analysis was based on a selective sample of procedures. All three fetuses with shunt displacement into the chest were asymptomatic at the final follow-up, despite the shunt not being removed. For more details, refer to the sources of evidence (see appendix).
|2.4.4||The Specialist Advisors noted a range of adverse events, including complications related to the shunt, such as dislplacement and blockage, trauma to the fetus, maternal infection and incidents of preterm labour and fetal death.|
Chairman, Interventional Procedures Advisory Committee
|Appendix:||Sources of evidence|
The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.
Available from: www.nice.org.uk/ip333overview
This page was last updated: 08 February 2011