Imaging Review of Procedural and Periprocedural Complications of Central Venous Lines, Percutaneous Intrathoracic Drains, and Nasogastric Tubes

Placements of central venous lines (CVC), percutaneous intrathoracic drains (ITDs), and nasogastric tubes (NGTs) are some of the most common interventional procedures performed on patients that are unconscious and in almost all intensive care/high dependency patients in one form or the other. These are standard procedures within the remit of physicians, and other trained health professionals. Procedural complications may occur in 7%–15% of patients depending upon the intervention and experience of the operator. Most complications are minor, but other serious complications may add significantly to morbidity and even mortality of already compromised patients. Imaging findings are the key to the detection of misplaced lines, and tubes and their prompt recognition are vital to avoid harm to the patient. It is, therefore, pertinent that healthcare professionals who perform these procedures are familiar with imaging complications of these procedures. Here, we present the imaging characteristics of procedural complications.


Introduction
Placements of CVC, ITD, and NGT are the most common interventional procedures performed on the seriously ill postoperative patients that are unconscious and in almost all intensive care/high dependency patients in one form or the other. These are standard procedures within the remit of physicians, and other trained health professionals. Procedural complications are significant, but most are classed as minor. However, complications that are more serious occur. Avoiding complications from CVC, ITD, and NGT placement is a subject of particular concern and interest in the ongoing era of quality and safety culture. Expected benefits need to outweigh the risk of complications. The corner stone in the detection of these complications is readily available appropriate imaging during and after the procedures.
Portable chest radiography is an essential clinical component of patient care in the intensivecare unit. Routine use not only shows unexpected cardiopulmonary abnormalities, but also plays an important role in the detection of malposition of various lines and tubes allowing prompt action [1,2]. Occasionally computed tomography (CT) is indicated. Until recently, the main stay of detecting complications was a standard chest (CXR) and/or an abdominal X-ray (AXR). However, the growing importance of bedside ultrasound as a tool of superior accuracy in diagnosing periprocedural complications needs to be emphasized [3,4]. Sonography is taking a greater share in the management of CVCs, NGTs, and percutaneous thoracic intervention resulting in  a diminishing role for a CXR. Ultrasound guidance is an accurate method of CVC misplacement detection leading some authors to opt for total abolishment of routine CXR after CVC placement [5]. Similarly, ultrasonography as an alternative method of confirming proper nasogastric tube placement has been proposed [6]. It has been suggested that the remaining indication for a CXR seems to be detection of the catheter tip malposition [7][8][9]. Studies from Italy [10] and France [11] suggest that ultrasound is an accurate method of CVC misplacement detection, leading some authors to opt for total abolishment of routine CXR after CVC placement. The physician or other healthcare professionals caring for these critically ill patients should be familiar with imaging features of complications caused to take the immediate and appropriate action. Here, we present imaging findings of minor and life threatening major complications. s Figure 3: A chest radiograph on 2-month-old following cardiac surgery. A difficult venous access prompted a right femoral vein access. The tip of the catheter has entered the right hepatic vein. Note the air at the tip of the catheter, which is a potential for air embolism (arrow).

Procedures Complications
Procedures complications from intrathoracic CVC, ITD, and NGT placement are significant, but most are considered minor. However, complications that are more serious occur. Avoiding complications from CVC, ITD, and NGT placement is a subject of concern and interest in the ongoing era of quality and safety culture. Expected benefits need to outweigh the risk of complications. The corner stone in the detection of these complications is readily available appropriate imaging during and after the procedures.
The physician or other healthcare professionals caring for these critically ill patients should be familiar with imaging features of complications caused to take the immediate and appropriate action. The Do's and Do not's of CVC, NGT, and ITB placements are summarised in Tables 1, 2, and 3 and which, form the basis of avoiding complications. Here, we present imaging findings of minor and life threatening major complications.
Image-guided placements reduce the risk of complications. Sonography is taking a greater share in the management of CVCs, NG tubes, and percutaneous thoracic intervention resulting in a diminishing role for a CXR. Ultrasound is an accurate method of CVC misplacement detection, leading some authors to opt for total abolishment of routine CXR after CVC placement [5]. Similarly, ultrasonography as an alternative method of confirming proper nasogastric tube placement has been proposed [6].

Central Venous Lines (Catheter) (CVC).
CVC is placed in one of the main veins including the jugular (internal or external), the subclavian, or the femoral vein. CVC lines are used to administer medications or fluids, obtain blood samples specifically for "mixed venous oxygen saturation," and directly obtain cardiovascular measurements such as the  Figure 6: Two patients with surgically installed subcutaneous ports anterior thorax before chemotherapy starts. The line will allow treatments to be given and blood samples obtained without being "stuck" with a needle. At the end of the treatment, the central line is removed. (a) It shows a looped catheter and (b) shows dissection of the vessel.       Figure 11: A CT scan on the same patient as in Figure 11 shows extensive bullous emphysema. The punctured bulla contains an air/fluid. central venous pressure. There are several types of central venous catheters in use for a variety of indications. The Metaanalysis study and National Institute of Clinical Excellence recommend that CVC lines be ultrasound guided [12,13].
Central venous line insertion may cause a number of complications. The benefit needs to outweigh the risk of Pulmonary Medicine 5 Figure 12: A CXR on a patient with thoracic trauma following a road traffic accident. Diagnosis of a hemopneumothorax was made, but before proceeding to a chest drain placement, a CT scan was obtained as a part of a work up for multiple traumas, which showed a diaphragmatic rupture and herniation of stomach into the left hemithorax explaining the air/fluid at the left lung base. those complications. Complications related to placement occur in approximately 15% [14][15][16]. Procedural complications occur in 5 to 19% of patients [5,6,15,16]. Infectious complications occur in 5 to 26% [5,7,15,17], whilst thrombotic complications occur in 2 to 26% [5,15]. The do's and do not's of CVP lines are summarized in Table 1.

Incorrectly Placed Catheters.
Accurately catheter tip placement of the intravenous catheter is crucial to its safe function. The distal points of short-term catheters are usually placed within the SVC, and long-term catheters are placed in the superior vena cava or just within the right atrium. Malposition as detected on chest X-rays in 3-14% of patients, with the catheter tip located in the internal jugular vein, opposite subclavian vein, axillary vein, internal thoracic vein, azygos vein, hemiazygos vein, or pericardiophrenic vein [18][19][20] (Figures 1, 2, 3, 4, and 5). Malposition in these locations is associated with higher complication rates such as pain, malfunction, phlebitis, and thrombosis [21,22]. Such  malpositioned catheters are associated with a high prevalence of pain, thrombosis, phlebitis, and malfunctions. Mention needs to be made of a persistent left superior vena cava [23]. A catheter would show in an abnormal position when placed in a persistent left superior vena cava when assessed on a standard A-P chest X-ray ( Figure 5). A quick squirt of contrast through the line would confirm the location of the catheter.
Extravascular location of catheter tips can cause extravasation, pneumothorax, hemothorax, or hemomediastinum ( Figures 6 and 7). A CXR may confirm the position of the catheter however; sometimes a lateral radiograph may be required for proper location. Imaging is necessary following every placement of an intravenous line as entry of solutions into the mediastinum or pleural space may have disastrous consequences. Failure to obtain free reflux of blood from the catheter at the time of insertion and following insertion should raise the possibility of abnormal location of the catheter tip.
When considering ultrasound-guided vascular puncture techniques many alternatives are available, which include low or posterior approaches of the internal jugular vein, puncture of the subclavian vein and its variant in children, infraclavicular access to the axillary vein, and also more peripheral punctures of the basilic, brachial, and cephalic veins [24].
Complications associated with insertion of central lines include bleeding, pneumothorax, hemothorax, arterial cannulation, and catheter displacement or break. Catheter  breakage occurs mainly with extensive catheter manipulation during difficult insertion. Another cause of catheter breakage according to the literature is the so-called "pinch-off " syndrome, where the CVC is compressed between the first rib and the clavicle, a phenomenon occurring in approximately 1% of all long-term CVCs' . This complication may result in catheter breakage with subsequent embolization of the distal portion [25]. Catheter kinking may also hinder flow, and it occurs most often in obese patients when the skin is drawn laterally and inferiorly during needle insertion. Following skin release, a right angle kink of the catheter can occur as it exits from under the clavicle running through the subcutaneous tissue to the exit site with another right angle and again at the skin, forming a Z-shaped deformity [13,26] (Figure 6).

Arterial Puncture.
Internal jugular vein catheterization is associated with a high rate of successful catheter placement. However, serious complications arise with internal jugular catheterization such as carotid artery puncture, pneumothorax, vessel erosion, thrombosis, and airway obstruction and infection. Rare complications include thyrocervical trunk, pseudoaneurysm, and fistula [27].
Inadvertent arterial puncture occurs in approximately of 3%-10%, usually does not result in serious consequences, but can occasionally lead to devastating complications (e.g., hematoma, pseudoaneurysm, or stroke) particularly if it goes unrecognized and a large-bore dilator or catheter is inserted [28]. The risk of CVC insertion-associated severe bleeding even in coagulopathic or thrombocytopenic patients is low (<5%) [29].  Figure 18: Axial CT scans on the same patient as in Figure 29 showing a large bulla in the right lower lobe associated with passive atelectasis in the right middle lobe. Note the surgical emphysema.  range from 0.1 to 15% [28,30,31] (Figure 7). Thin, malnourished patients, and patients with COPD, and those on high-pressure ventilatory support are at an increased risk. The pneumothorax is usually small, and most patients remain asymptomatic and resolve without intervention. Occasionally a pneumothorax is not seen on the first postinsertion CXR and becomes a few days later. Difficult insertions, particularly when several passes are made and when air is aspirated and in patients that complain of pleuritic pain a normal initial CXR may require a repeat CXR in 6-12 hours post-insertion. Most delayed pneumothoraces resolve spontaneously. Spiliotis and associates conducted a prospective study of 343 catheter placements via the subclavian vein describe a 2.2% delayed pneumothorax rate recognised 48 and 72 hours after the catheter placement [26,32]. Figure 22: Axial CT scans on the same patient as in Figure 22 showing inappropriately placed chest drain in an attempt to drain a right basal pleural effusion. In another retrospective study, one hundred fourteen patients having 121 subclavian venipunctures were studied, where eight pneumothoraces occurred (6.6%) and were most frequent after the insertion of large catheters, or when the subclavian area was distorted by previous venipuncture or radiation. Delayed pneumothorax occurred in five patients detected 8-96 hours following the venipuncture. All patients in the study with delayed pneumothoraces required a tube thoracotomy [27,33].

Chylothorax.
A chylothorax due thoracic duct injury may follow a subclavian vein or jugular vein catheterization is uncommon complication and reported in 1-4.2% [34].
This complication is rarely recognised immediately, but leakage of lymphatic fluid at the puncture site may become apparent over time, making dressing care difficult, or a CXR may reveal nonspecific pleural effusion. Rarely a fluctuant swelling is seen at the root of the neck.  and accidental disconnection of intravenous tubing from the central venous catheter. Symptoms are dependent on the amount and rate at which air is aspirated. Patients may suffer from dyspnea, chest pain, and cyanosis. The patient may become disoriented and comatose. Physical examination may reveal tachycardia and hypotension. The diagnosis can be confirmed by a cross-table CXR with the right side up. Air may be seen in the pulmonary arteries and/or the right ventricle [35][36][37][38] (Figure 8).

Percutaneous Thoracic Drains.
There is a variety of indications for placement of chest drains. Physicians and technologists from many specialties are trained on the methods that can allow them to safely perform tube thoracostomy with 3% early and 8% late complications. The National Patient Safety Agency (UK) reported 2152 complications that were related to chest drain placements between January 2005 and March 2008. Fifteen serious complications and 12 fatalities were reported. Most serious complications were related to the site of drain insertion. This issue has raised concern regarding the risk of incorrect placement of chest drains and adequacy of training amongst those responsible for chest drain insertion [34][35][36][37][39][40][41][42][43].
The use of a trocar has been linked to a significant incidence of intraparenchymal and intrafissural insertion of chest drains. Remérand and his colleagues in a review of 122 patients with chest drain insertion followed by CT found 21% of drains to be intrafissural and 9% to be intraparenchymal with the only predicting factor associated with the risk of malposition was the use of a trocar for the insertion of the chest tube [43].
British Thoracic Society (BTS) guidelines recommend that placement of a chest drain is indicated for a malignant pleural effusion, empyema, traumatic hemothorax, some pneumothoraces, and in some postoperative states, such as after cardiac surgery. BTS guidelines recommend that all elective drains should be inserted in the "triangle of safety". The triangle of safety is defined as the area bordered by the anterior margin of latissimus dorsi, the lateral edge of pectoralis major, and a line superior to the horizontal level of the nipple with the apex below the axilla. Inappropriate insertion of a chest drain can cause serious harm or even death. Although placement of a chest drain in the   This route is not routinely taken as it may be uncomfortable for the patient and may produce an unsightly scar [43][44][45]. Alternative insertion sites are also considered as in loculated pleural effusions where choosing a posterior site may be more appropriate. When draining loculated pleural effusions ultrasound guidance may provide a safer approach. Image-guided thoracocentesis has a higher success rate and lower complication rate [46][47][48][49][50].  Placement of chest drains is a common hospital procedure; most are placed safely without complications. Nevertheless serious and fatal complications may occur. All manner of misplaced chest drains has been described. Perforation of the pericardium, cardiac chambers, injury to the aorta, thoracic duct and stomach, spleen, and liver has been described. A diaphragmatic rupture has been misinterpreted as a pneumothorax, and stomach contents have been drained [45,46] (Figures 9, 10 , 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30). It is important that a pseudopneumothorax and lung bullae are recognized to prevent inadvertent placement chest drain placement. The do's and do not's of percutaneous chest drains are summarized in Table 2 [44,50].  (i) Do use to gain peripheral venous access, deliver substances not safely given via peripheral IV access, hemodialysis, plasmapheresis, measurement of cardiac filling pressures, placement of pulmonary artery catheter, placement of trans venous pacer and access for frequent blood sampling.
(ii) Do not use if operator inexperienced, uncooperative patients and uncorrected coagulopathy.
(iii) Do not use or use with caution in cellulitis/infected at anticipated insertion site, previous surgery/injury SVC, severe respiratory disease that cannot tolerate a pneumothorax (consider femoral route), when adequate peripheral access is available, vasculitis, congenital heart disease, presence of cardiac pacemaker and or other intracardiac devices.
(iv) Do get informed consent for elective placement. In an emergency, do document the need in records.
(v) Do make sure all materials are within reach before the commencing the procedure. can be uncomfortable with inadequate local anesthetic to the nasal passages and lack of instruction to patients on how to cooperate with the operator during the procedure. Inexperienced or inaccurate placement may not only be distressing to patients, but also could cause significant harm or even death. The clinical signs of NGT misplacement in intensive care patients may be absent or misleading. Chest radiography is  [44,50].  accurate in the detection of misplaced NGT. Chest radiography is particularly helpful in detecting NGT misplacement. The complication rates associated with fine bore NGTs varies from 0.35 to 8% [45,51] (Figures 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, and 41). The Do's and Do not's of NGT are summarized in Table 3.  Figure 38: A CXR shows entry of the NGT into the right lower lobe bronchus. The patient was severely ill and went into respiratory distress following delivery of fluids down the NGT. There was a delay in the diagnosis of the patient developing an abscess at the right lung base. The patient had a cholangiocarcinoma and had an unsuccessful attempt at external biliary drainage (PTC (a)).
(a) (b) Figure 39: Two images from a water-soluble contrast swallow showing an esophageal perforation from an NGT in this case with esophageal varices.
(a) (b) Figure 40: Axial CT scans of the same case as Figure 38 showing entry of water-soluble contrast into the right pleural space following esophageal perforation from an NGT.
displacement of a small bowel tube into the stomach of a patient with significantly slowed gastric motility. Rassias reported a 2% incidence of tracheopulmonary complications among 740 tube insertions and 0.3% died from the complications [47,52].
Complications related to malpositioned feeding tubes are usually preventable. Some pulmonary complications related to NG misplacements can be particularly significant. Bronchial placement leads to atelectasis, pneumonia and eventually developing into lung abscess. Other respiratory complications include bronchial perforation, perforation into the pleural cavity and pneumothorax, hydrothorax, rarely pulmonary hemorrhage, and pleural knotting of the NGT [51][52][53][54][55]. (i) Do not intubate some patients with maxillofacial disorders, following maxillofacial surgery or trauma, esophageal tumors or surgery, laryngectomy, oropharyngeal tumors, skull fractures, unstable cervical spinal injuries (involving vertebrae 4 or above), and esophageal varices. (ii) Do explain the procedure to the patient. (iii) Do wear nonsterile gloves. (iv) Do wear a mask, eye protection, and a gown when dealing with patients prone to vomiting.
(v) Be ready to apply suction when gaging/vomiting occurs. (vi) Do sit patients upright for optimal neck/stomach alignment if possible. (vii) Do examine the nostrils for obstruction; use the best side for intubation. (viii) Do measure tube from bridge of nose to earlobe, and to halfway between the inferior part of the sternum and the umbilicus.

Intravascular
Complications. Accidental intravascular placement in right internal jugular vein down into the right atrium has been reported. Placement of an NG tube into an aberrant right subclavian artery through an esophageal erosion has also occurred [56,57]. Feeding tubes should be avoided in those known to have an aberrant right subclavian artery. Fatal hematemesis has been reported [56,57].

Enteral Complication.
NGT knotting is a rare complication, can occur in various locations, and case reports describe knotting/impaction in the nasopharynx and beyond the pylorus. Other NG tube complications include reentry of the esophagus following a loop in the stomach, tube breakage, tube blockage, and rupture with syringing and gastrointestinal perforation. Esophageal perforation and subsequent mediastinitis may occur [58,59].

Intracranial Entry.
Intracranial placement of an NG tube has occurred following repair of choanal atresia, transsphenoidal surgery and maxillofacial trauma [60,61].

Summary
Procedural complications may occur in 7%-15% of patients during placement of CVC, ITD, and NGT. Serious complications may add significantly to morbidity and mortality of already compromised patients. Imaging findings are the key to the identification of misplaced lines, and tubes, and their prompt recognition are essential to avoid harm to the patient. All those that indulge performing the procedures to avoid harm to patients must recognize these imaging findings. Imaging characteristics of these complications are described, and ways to identify them are discussed.