Tube thoracostomy is a commonly performed procedure in both human and veterinary medicine to evacuate gas or fluid from the pleural space, either following pleural effusion or pneumothorax alone or as part of thoracic surgical procedures [1–6].
While thoracocentesis is primarily used for diagnostic sampling and patient stabilization, thoracostomy tube (TT) placement is indicated in patients with recurrent pneumothorax, tension pneumothorax, rapidly accumulating pleural effusion, pyothorax, and following thoracotomy [7].
Large-bore thoracostomy tubes (LBTT) have traditionally been used for evacuation of large amounts of non-viscous, viscous and fibrinous/flocculent fluids [8, 9], while small-bore thoracostomy tubes (SBTT) have been introduced for evacuating air and non-viscous fluids [10–12]. Differentiation is also made based on the method of insertion, which can be through a trocar technique, blunt dissection into the pleura (mini-thoracotomy), or a modified Seldinger guide-wire technique [7, 11, 13–16]. The most commonly used drainage systems in veterinary patients include traditional large-bore trocar tubes (TRO), small-bore wire-guided thoracostomy tubes (SBWGTT), and Jackson Pratt thoracostomy drains (JP) [11, 13, 17, 18], with the latter used exclusively intraoperatively during thoracic surgery to provide relieve of postoperative pneumothorax or pleural effusions [17].
In both human and in veterinary medicine, large-bore trocar drains have become less popular due to their high complication rate [3, 15, 19, 20]. Reported insertional complication rates associated with LBTT range from 3 to 35 % in humans [2, 20–24] ad up to 58 % in veterinary patients[14, 15, 25–28]. Trocar drains as well as the “mini-thoracotomy” technique typically require general anesthesia, which may not be suitable for cardiovascular unstable or dyspneic animals [7, 25, 26, 29].
The Seldinger technique has gained popularity in both human medicine [30, 31] and veterinary medicine over the past decade due to its ease of use and patient comfort [11, 17, 32]. It offers a simpler alternative for chest drain placement in both small animals and humans [11, 31–33]. SBWGTT are recommended for treating pneumothorax and malignant effusion in humans due to fewer insertional and infectious complications and better patient tolerance [34–37].
Valtolina et al. (2009) first described insertion of SBWGTT using the modified Seldinger technique in dogs and cats, noting minimal insertional complications and quick thoracic evacuation [11]. Del Magno et al. (2020) also presumed SBWGTT to be a safe option for managing feline pyothorax with lower complication rates [11, 33].
Despite the benefits of thoracostomy tube drainage, various complications can arise [2]. In human medicine, tube thoracostomy is linked with significant morbidity [21]. Reported complications encompass incorrect placement (e.g. entering too far cranially or insufficiently into the thorax), failure to evacuate the pleural space (obstruction of the tube with fibrinous debris, coiling or kinking of the tube), unresolved pneumothorax (persistent air leakage or residual pneumothorax), persistent effusion, infection, air and/or fluid leakage, stoma site discharge, stomal infection, empyema, lung tissue irritation, re-expansion pulmonary edema, phrenic nerve irritation or neuropraxia, injury to the sympathetic chain, injuries to intercostal or intrathoracic vessels, injuries of the diaphragm or the subdiaphragmatic viscera, premature accidental tube removal or dislodgement, and inadvertent loss of negative intrathoracic pressure resulting in pneumothorax [7, 17, 22, 28, 38–40].
Merca et al. (2021) conducted a retrospective evaluation of the complication rates of four types of thoracostomy tubes in 201 dogs and 139 cats, with a total of 455 drains placed. They established a classification scheme for complications, which included positional (33.1%), infective/immunologic (19.4%), instructional/educational/equipment related (19.1%), removal (8.2%), insertional (7%), and self-mutilation-related (5%) issues. Over-the-wire and blunt and sharp wide-bore tubes were most associated with positional, infective or equipment-related complications [41]. Thus, thoracostomy tube placement, although common in human medicine and veterinary medicine, carries the potential for significant morbidity and mortality [2, 21, 38].
In our experience, SBWGTT[1] can pose challenges during placement and use. Clinical observations in our institution have shown instances in which patients (both cats and dogs) developed lung lacerations following SBWGTT placement. One case involved a dog, in which SBWGTT were inserted bilaterally into the lung lobes, and unfortunately, one cat died due to this complication. A retrospective study by Boullhesen Williams et al. in 2022 shared our concerns regarding the safety of these drainage systems, reporting a substantial complication rate of 32%, with 21.7% technical and 14.1% insertional issues [18].
The aim of our study was to investigate the correlation between patients’ recumbency, placement method, and the occurrence of insertional complications in order to determine factors increasing safety and minimizing risk of complications during thoracostomy tube placement with a SBWGTT.
We hypothesized that for the treatment of pneumothorax, SBWGTT produces fewer insertional complications in lateral recumbency compared to sternal recumbency, and vice versa for the treatment of fluid-filled thoraces.
To the author’s knowledge, no studies have been published comparing different recumbencies for thoracostomy tube placement using small-bore wire-guided thoracostomy tubes in different pleural cavity conditions.