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CASE REPORT Table of Contents   
Year : 2007  |  Volume : 10  |  Issue : 2  |  Page : 137-139
Spontaneous uncoiling of a knotted pulmonary artery catheter

Department of Anaesthesiology & Intensive Care, GB Pant Hospital, JL Nehru Marg, New Delhi., India

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How to cite this article:
Naz A, Ganjoo P, Tandon MS, Chawla R. Spontaneous uncoiling of a knotted pulmonary artery catheter. Ann Card Anaesth 2007;10:137-9

How to cite this URL:
Naz A, Ganjoo P, Tandon MS, Chawla R. Spontaneous uncoiling of a knotted pulmonary artery catheter. Ann Card Anaesth [serial online] 2007 [cited 2022 Nov 29];10:137-9. Available from:

   Introduction Top

Flow-directed, balloon-tipped pulmonary artery (PA) catheters are often used to guide haemodynamic management during cardiac as well as non-cardiac surgery. Whether benefits of the catheter actually outweigh the associated risks, justifying their insertion, is a topic of on-going debate. One of the well known complications of catheter insertion is the knotting and entrapment of the catheter inside the heart. [1],[2],[3],[4] A variety of surgical as well as non-surgical methods have been successfully used to retrieve the stuck catheter. We report a patient in whom the PA catheter got looped and knotted inside the heart during its insertion. Under fluoroscopy, further insertion of the catheter resulted in a spontaneous release of the knot.

   Case report Top

A 65-year-old-man, with subarachnoid haemorrhage was diagnosed to have a right anterior communicating artery aneurysm. He was scheduled to undergo urgent craniotomy and clipping of the aneurysm. Preoperative hypertension, left ventricular hypertrophy and ST changes on electrocardiogram prompted us to place a PA catheter for intraoperative haemodynamic monitoring. Following induction of anaesthesia, an 8.5 F introducer sheath was placed into the right internal jugular vein and through it a 7.5 F flow-directed PA catheter (Edwards Lifesciences, Irvine, CA, USA) was inserted up to the 20 cm mark. The balloon was inflated and the catheter was slowly advanced further to reach the right ventricle (RV), which was confirmed by the characteristic RV waveform on the monitor. The RV was reached at 35 cm. On further advancement of 15-20 cm, the catheter did not reach the PA. Catheter was withdrawn up to the right atrium after deflating the balloon and was advanced again after reinflation of the balloon. Several such attempts were made, and during one such attempt, the catheter got inadvertently inserted up to the 70 cm mark, but a PA waveform was still not obtained. During withdrawal of the catheter, resistance was encountered at the 35 cm mark; at this stage right atrial tracing was seen. While the catheter could be pushed inside freely, pulling it out was difficult. A gentle tug on the catheter proved futile; no extra force was applied to pull it out. Since, the tip of the catheter was in the right atrium and there were no arrhythmias, it was decided to leave the catheter undisturbed till the surgery was completed. An uneventful clipping of the aneurysm was performed. Before reversal of anaesthesia, fluoroscopy of the chest was performed with a C-arm fluoroscope and the catheter was found to be looped and knotted at the end of the introducer sheath. Major part of the loop was in the superior vena cava (SVC) and the catheter tip was at the junction of SVC and right atrium [Figure 1]. Under fluoroscopic vision, the catheter was slowly advanced forward and the knot was seen to uncoil spontaneously [Figure 2]. Soon the knot got completely untied and the catheter could be easily pulled out.

Patient was transferred to the intensive care unit after surgery. An echocardiogram at this time showed left ventricular hypertrophy, mild diastolic dysfunction, left ventricular ejection fraction of 55% and no valvular abnormality. The patient had an uneventful recovery.

   Discussion Top

Knotting of a PA catheter was first reported by Johansson and colleagues in 1954. [2] The current estimated incidence is 0.065% of total insertions. [3] It is most commonly encountered when the catheter is advanced excessively, which causes it to bend on itself resulting in knot formation. [2],[4] This usually occurs in the RV. A looped or knotted catheter can be easily diagnosed by chest X ray. [3],[5] Echo­cardiography (transthoracic or transoesophageal) and fluoroscopy [1],[3] are other useful diagnostic techniques. Once catheter entrapment is confirmed, excessive force should not be used to withdraw it. This can further tighten the knot and if the catheter has looped around some cardiac structure, it can lead to catastrophic consequences. [3]

Surgical as well as non-surgical methods have been described for removing the entrapped catheter. Surgical removal is advocated if the catheter is entrapped by a perforating surgical suture or if the knot is firmly tightened around some cardiac structure. [2],[3] Among the non-surgical methods, untying the knot using a guide wire and an endomyocardial biopsy forceps passed through the femoral vein, [5] tightening the knot to reduce its size and then removing it along with the introducer sheath [1] and use of a retrieval basket or a loop snare, have all been described. [2] These procedures are performed under fluoroscopic guidance by an experienced interventionist. The likelihood of catheter knotting can be substantially decreased, if excessive insertion of the catheter is avoided. The guidelines for length of insertion of PA catheter to locate different cardiac chambers are available [6] and these should be strictly followed.

In the present patient, the catheter could not be negotiated into the PA. The common causes of failure to enter the PA from the RV are, right ventricular outflow tract obstruction, pulmonary stenosis, ventricular septal defect, etc. As none of these were present in our patient, the exact cause of failure remains unknown. It appears that repeated attempts and excessive insertion caused the catheter to coil on itself and resulted in knotting. Thus, this report reinforces the advisability of being precise during insertion and avoiding forceful withdrawl of the catheter, if a knot is suspected. This will keep the knot loose, which may assist spontaneous untying.

   References Top

1.Kao MC, Lin SM, Yu YS, Huang YC, Ting CK, Tsai SK. Knotted continuous cardiac output thermodilution catheter diagnosed by intraoperative transoesophageal echocardiography. Br J Anaesth 2003; 91: 451-452.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2.Georghiou GP, Vidne BA, Raanami E. Knotting of pulmonary catheter in superior vena cava: surgical removal and a word of caution. Heart 2004; 90: e28.  Back to cited text no. 2    
3.Jacobson E, Fessler DA, Rosemeier F, Tymkew H, Avidan M. Morbidity and mortality associated with accidentally entrapped pulmonary artery catheters during cardiac surgery: A case series. J Cardiothorac Vasc Anesth 2006; 20: 371-375.  Back to cited text no. 3    
4.Matsuda T, Inoue S, Keiichi S, Furuya H. Images in anaesthesia: Accidental knot formation of a pulmonary artery catheter. Can J Anesth 2004; 51: 1010.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.Mehta N, Lochab S, Tempe DK, Trehan V, Nigam M. Successful nonsurgical removal of a knotted and entrapped pulmonary artery catheter. Cathet Cardiovasc Diagn 1998; 43: 87-89.  Back to cited text no. 5    
6.Tempe DK, Gandhi A, Datt V, et al. Length of insertion of pulmonary artery catheters to locate different cardiac chambers in patients undergoing cardiac surgery. Br J Anaesth 2006; 97: 147-149.  Back to cited text no. 6  [PUBMED]  [FULLTEXT]

Correspondence Address:
Pragati Ganjoo
Department of Anaesthesiology & Intensive Care, GB Pant Hospital, JL Nehru Marg, New Delhi.
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-9784.37940

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  [Figure 1], [Figure 2]