Observational Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Anesthesiol. Jul 27, 2015; 4(2): 30-38
Published online Jul 27, 2015. doi: 10.5313/wja.v4.i2.30
Transthoracic echocardiography assists appropriate pulmonary artery catheter placement: An observational study
Chong Oon Tan, Laurence Weinberg, David Andrew Story, Larry McNicol
Chong Oon Tan, Laurence Weinberg, David Andrew Story, Larry McNicol, Department of Anaesthesia, the Austin Hospital, Heidelberg, Victoria 3084, Australia
Chong Oon Tan, Laurence Weinberg, David Andrew Story, Larry McNicol, Department of Surgery, Melbourne Medical School, the University of Melbourne, Victoria 3010, Australia
Author contributions: Tan CO conceived and designed the study, was involved in data collection, analysed and interpreted data, drafted and revised the manuscript, gave approval for the final manuscript, and agrees to be accountable for all aspects, accuracy and integrity of the work involved; Weinberg L and Story DA assisted in conceptualisation and design of the study, was involved in data collection, analysed and interpreted data, revised the manuscript, gave approval for the final manuscript, and agrees to be accountable for all aspects, accuracy and integrity of the work involved; McNicol L assisted in design of the study, revised the manuscript, gave approval for the final manuscript, and agrees to be accountable for all aspects, accuracy and integrity of the work involved.
Institutional review board statement: This study was approved by the Austin Health Human Research and Ethics Committee (H2012/04776) and was carried out in compliance with the Helsinki Declaration on research involving human participants.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment. All study data was de-identified for analysis.
Conflict-of-interest statement: There were no conflicts of interest to declare.
Data sharing statement: We hereby regretfully decline to have the following data components of our study placed in the Dryad Repository: Technical appendix; Statistical code; Raw dataset.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Chong Oon Tan, MBBS, FANZCA, PG Dip Clinical Ultrasound - Staff Anesthesiologist, Department of Anaesthesia, the Austin Hospital, 145 Studley Rd, Heidelberg, Victoria 3084, Australia. drchongtan@gmail.com
Telephone: +61-3-94965704 Fax: +61-3-94596421
Received: April 6, 2015
Peer-review started: April 8, 2015
First decision: April 27, 2015
Revised: May 12, 2015
Accepted: June 1, 2015
Article in press: June 2, 2015
Published online: July 27, 2015
Processing time: 111 Days and 13.7 Hours
Abstract

AIM: To investigate the utility of transthoracic echocardiography in confirming appropriate pulmonary artery catheter (PAC) placement.

METHODS: Three commonly used transthoracic echocardiography (TTE) views were used to confirm PAC position in 103 patients undergoing elective cardiac surgery - the parasternal short axis right ventricular inflow-outflow view; the subcostal short axis right ventricular inflow-outflow view; and the parasternal short axis ascending aortic view. All PACs were inserted by the managing anesthesiologist under pressure waveform guidance alone, who was blinded to all sonographic information. A sonographer blinded to all pressure waveform information confirmed visualisation of an “empty” PA before PAC insertion, and visualisation of the PAC balloon in the main PA (MPA) or right PA (RPA) after attempts at placement were complete. Agreement, sensitivity and specificity of TTE in confirming appropriate PAC placement was compared against pressure waveform guidance as the “gold standard”. The successful view used was compared against patients’ anthropomorphic indices, presence of lung hyperinflation, and insertion of PAC during positive pressure ventilation. Agreement between TTE and pressure waveform guidance was analysed using Cohen’s Kappa statistic. The relative proportion of total RPA seen by subcostal vs parasternal TTE views was also compared with a further 20 patients’ computed tomography (CT) pulmonary angiograms (CTPA), to determine efficacy in detection of distal RPA PAC placement.

RESULTS: Appropriate positioning of the PAC balloon, and its to-and-fro movement consistent with a non-wedged state, within the MPA or RPA was confirmed by TTE in 98 of the 103 patients [sensitivity 95% (95%CI: 89%-98%)], and absence of the PAC balloon before insertion correctly established in 100 patients [specificity 97% (92%-99%)]. This was in very good agreement with pressure waveform guidance [Cohen’s Kappa 0.92, (0.87-0.98)]. The subcostal view was the best view to visualise the PAC tip when it was placed in the right pulmonary artery (OR 70, P < 0.0001), was more successful in patients with COAD (OR 9.5, P = 0.001), and visualized 61% (vs 44% by parasternal views, P < 0.001) of mean RPA lengths compared with CTPA; however the parasternal views were more successful in patients with higher body mass indexs (OR 0.78 for success with subcostal views, P < 0.001). There was a trend towards insertion during intermittent positive pressure ventilation favoring visualisation by subcostal views (OR 3.9, P = 0.08). The subcostal view visualized a greater length of the RPA than parasternal views (3.9 cm vs 2.9 cm, P < 0.0001). PACs were more often placed in the MPA than RPA (80 vs 18 patients). Three patient’s pulmonary arteries were not visible by any TTE view; in a further 2 patients, despite pre-insertion visualisation of their pulmonary arteries, the PAC balloon was not visible by any view with TTE where correct placement by pressure waveform was unequivocal.

CONCLUSION: TTE can assist appropriate PAC placement by visualization of an unwedged PAC balloon in the PA.

Keywords: Transthoracic echocardiography; Pulmonary artery catheter; Main pulmonary artery; Right pulmonary artery; Pulmonary artery rupture; Intensive care unit

Core tip: Transthoracic echocardiography (TTE) is an efficacious adjunct to pressure waveform guidance for guiding appropriate pulmonary artery catheter (PAC) placement. With the required equipment and expertise, TTE is a rapid and safe tool for confirming whether the PAC is placed too far (the PAC balloon seen beyond the proximal RPA) or not far enough (the body of the PAC seen in the right ventricle but the PAC balloon not seen in the main PA or right PA). This application may assist in reducing complications related to PA rupture or PAC induced arrhythmias.