Thoracic medicine has undergone significant advances over the years, and chest drainage has become a crucial tool in the management of various conditions. Pioneers in this field include the British scientist Sir Hugh Owen Thomas (1), who contributed to the development of orthopaedic techniques and whose treatment principles influenced several areas of medicine, including thoracic surgery and the development of drainage.

To understand the importance of thoracic drainage, it is essential to consider the physiology of the respiratory system. The pleural space, which surrounds the lungs, normally contains a small amount of fluid that acts as a lubricant (2). When air or fluid accumulates in the pleural space due to pathologies such as pneumothorax or pleural effusion, thoracic drainage becomes a crucial intervention to restore normal lung function (3).

Types of chest drainage:

Chest drainage is a crucial intervention in the clinical setting. They can be classified according to access (surgical or non-surgical), the principle of debit extraction (by suction or gravity) or by their sealing system (dry seal or wet seal) (4). There are different clinical practice guidelines that recommend the use of active cleansing drains to reduce complications such as cardiac tamponade or haemothorax (5). But what all drains have in common is the type of sealing used by the drainage devices, either dry or wet sealing. There are differences between each type of sealing that allow us to make a better decision regarding their choice:

Dry seal thoracic drainage:

This method involves the use of closed chest drainage systems incorporating a dry seal, blood collection reservoir, air leak detector, suction bulb and regulator, high negative pressure release window and tube roller. This design has the advantage of preventing the entry of air from the outside into the pleural cavity, thus avoiding the risk of secondary pneumothorax. (6)

The key aspects of dry seal chest drainage are detailed below:

  • To confirm Pneumothorax: we must press the bulb (balloon), it will not remain compressed, but will initially dilate/inflate again. (If it does not, this confirms absence of air at the tip of the catheter/probe and therefore that the catheter/probe is not placed in the pleural space (or the pneumothorax has resolved)). (7)
  • To confirm Hemotorax: We must press the bulb (balloon) and blood can be observed in the tube (7).

Illustration 1: SINAPI type dry sealing device and illustration of the different positions of the suction bulb.
Illustration obtained from the official Cardiolink website

Wet seal thoracic drainage:

In this approach, the system uses water to create a seal in the collection chamber, allowing air to escape, but preventing it from returning to the pleural cavity.

Illustration 2: Thoracic drainage of single collection wet aspiration / wet seal, pleurevac

Both methods have their own advantages and disadvantages (Table 1). Dry seal drainage is more efficient in preventing external air ingress and is less prone to clogging compared to wet seal. However, the wet seal may be preferred in cases of pleural effusions with large amounts of fluid, as it allows better visualisation of the amount and characteristics of the fluid drained (7).

FeaturesDry Seal DrainageWet Seal Drainage
Prevention of Secondary PneumothoraxHighModerate
Propensity to ObstructionsLowModerate/High
  Liquid Drainage CapacityEfficient for less viscous liquidsEfficient for large volumes and dense liquids
Drainage VisualisationLowerHigher
Secondary Pneumothorax RiskLowModerate
  Adaptability to Different CasesLimited by fluid typeVersatile, effective in different conditions
  System ComplexityLess complex, closed systemsMore complex, requires water seal
  Visual Seal AssessmentNo direct display of the sealDirect display of the seal
Complication rateLowModerate
Initial cost of equipmentModerate/HighModerate
Maintenance costLow/ModerateModerate/High
Cost of disposable devicesLowModerate/High
Total long-term costModerate/HighModerate/High
Table 1: This table provides a quick comparison of the key characteristics between dry seal and wet seal drainage.

Scientific evidence suggests that the choice between dry seal and wet seal drainage should be based on the specific clinical condition and individual patient characteristics. There is no one-size-fits-all approach.

In general, ongoing research in this field seeks to optimise the benefits of both methods and to develop new technologies that improve the efficacy and safety of chest drainage. The choice between dry and wet seal should be made on an individual basis, taking into account the evolving scientific evidence and the specific clinical needs of each patient.

References:

  1. Hugh Owen Thomas [Internet]. Biografiasyvidas.com [cited 2024 Jan 22]. Available from: https://www.biografiasyvidas.com/biografia/o/owen_hugh.htm.
  2. Respiratory physiology: the amazing system that starts when we breathe in [Internet]. www.elsevier.com. Elsevier; 2017 [cited 2024 Jan 22]. Available from: https://www.elsevier.com/es-es/connect/fisiologia-respiratoria-el-asombroso- sistema-que-arranca-cuando-inspiramos.
  3. Chest drains [Internet]. Jamanetwork.com [cited 2024 Jan 22]. Available from: https://sites.jamanetwork.com/spanish-patient-pages/2019/hoja-para-el-paciente- de-jama-190827.pdf.
  4. Nursing care in chest drains [Internet]. ▷ RSI – Health Research Journal. 2023 [cited 2024 Jan 22]. Available from: https://revistasanitariadeinvestigacion.com/cuidados- de-enfermeria-en-los-drenajes-toracicos/.
  5. Pajares MA, Margarit JA, García-Camacho C, García-Suarez J, Mateo E, Castaño M, et al. Intensified clinical recovery pathway in cardiac surgery. Consensus document of the Spanish Society of Anaesthesiology, Resuscitation and Pain Therapy (SEDAR), the Spanish Society of Cardiovascular and Endovascular Surgery (SECCE) and the Spanish Association of Perfusionists (AEP). Rev Esp Anesthesiol Reanim [Internet]. 2021;68(4):183-231. Available from: https://www.sedar.es/images/images/site/SECCIONES/cardiotoracica/Via_clinica_d e_recuperacion_intensificada_en_cirugia_cardiaca._Documento_de_consenso_de_la_Sociedad.pdf
  6. Val-Jordán E, Fuentes-Esteban D, Vicente-Gordo, Miranda-Roy N, Martínez-Allueva I, Bosque-Gómez MP. Update on the approach to thoracic drainage. Sanid Mil [Internet].  2022  [cited  2024  Jan  22];78(4):273-8.  Available  from: http://scielo.isciii.es/scielo.php?script=sci_arttext&pid=S1887- 85712022000400012
  7. INSTRUCTIONS Sinapi [Internet]. Sinapibiomedical.com [cited 2024 Jan 22]. Available from: http://sinapibiomedical.com/wp-content/uploads/2020/09/Sinapi- Chest-drain-XL1000SC-IFU.pdf
  8. Estrada Masllorens M, Galimany Masclans J, Antonio J, Guerrero S. Closed thoracic drainage [Internet]. Diposit.ub.edu. [cited 2024 Jan 22]. Available from: https://diposit.ub.edu/dspace/bitstream/2445/33264/1/616914.pdf