Transthoracic echocardiography assists appropriate pulmonary artery catheter placement: An observational study

Table 1 Patient study parameters

Parameter	Number (proportion or 95%CI) or mean (SD or 95%CI)
Age (yr)	67 (10)
BMI (kg/m2)	29.6 (5.6)
IPPV during PAC insertion	24 (24%)
Diagnosis of COAD or Asthma	28 (28%)
Final PAC position in MPA	80 (72%-88%)	P < 0.0001
Final PAC position in RPA	18 (13%-29%)	P < 0.0001
TTE view in which PAC was seen
PSRVIO	52 (43%-63%)	P < 0.0001
SCRVIO	33 (26%-45%)	P < 0.0001
PSAscAo	13 (6%-24%)	P < 0.0001

BMI: Body mass index; IPPV: Intermittent positive pressure ventilation; COAD: Chronic obstructive airways disease; PAC: Pulmonary artery catheter; MPA: Main pulmonary artery; RPA: Right pulmonary artery; TTE: Transthoracic echocardiography; PSRVIO: Parasternal right ventricular inflow outflow view; SCRVIO: Subcostal right ventricular inflow outflow view; PSAscAo: Parasternal ascending aorta short axis view.

Table 2 Influence of patient factors and pulmonary artery catheter position on successful pulmonary artery catheter visualisation by subcostal views¹

	Odds ratio	P-value	95%CI
Diagnosis of COAD or Asthma	9.5	0.001	2.5-36
Insertion during IPPV	3.9	0.08	0.8-17.8
BMI (kg/m2)	0.78	< 0.0001	0.67-0.89
RPA PAC position	70.0	< 0.0001	9.6-502

¹Data are expressed as [number, (proportion)] or [mean, (SD)]. COAD: Chronic obstructive airways disease; IPPV: Intermittent positive pressure ventilation; BMI: Body mass index; RPA: Right pulmonary artery; PAC: Pulmonary artery catheter.

Table 3 Transthoracic echocardiogram length of right pulmonary artery visualised

TTE	Length (cm)		P-value
	Mean (SD)	Range
Parasternal views: RPA	2.9 (0.8)	1.2-4.8	< 0.0001
SCRVIO view: RPA	3.9 (0.8)	2.8-5.6

Data are presented as mean (SD). TTE: Transthoracic echocardiogram; RPA: Right pulmonary artery; SCRVIO: Subcostal right ventricular inflow outflow.

Table 4 Computerised tomographic pulmonary angiogram measurements of the right pulmonary artery and 1^st divisions

CTPA	Length (cm)		Width (cm)
	Mean (SD)	Range	Mean (SD)	Range
RPA	6.4 (1.0)	4.5-8.1	2.0 (0.4)	1.1-2.6
RPA 1st division (anterior)			0.8 (0.02)	0.4-1.4
RPA 1st division (posterior)			0.7 (0.02)	0.4-1.3

Data are presented as mean (SD). CTPA: Computerised tomographic pulmonary angiogram; RPA: Right pulmonary artery.

Table 5 Situations where utilisation of transthoracic echocardiogram for pulmonary artery catheter positioning may be of assistance

Timing	Utility
Pre-insertion	Identify RV dilation, suggesting a longer than standard PAC insertion distance until the MPA/RPA is reached by the PAC balloon
	Identify small calibre MPA/RPA dimensions, usually associated with hypovolemia, and possibly predisposing to shorter depths of insertion from RV to “wedge”
	Quantify RA, TV and PV abnormalities and/or degree of regurgitation prior to PAC insertion
Insertion	Establish absence of the body of the PAC within the RVOT, suggesting PAC coiling or failure of passage past the TV
	Establish presence of the body of the PAC within the RVOT, confirming that the PAC balloon (1) is not coiled in the RV and (2) must be either in or distal to the MPA/RPA
	Visualisation of an “un-wedged” PAC balloon by the appearance of “to-and-fro” movement of the echogenic air-filled PAC balloon in the MPA or RPA
	Imply a wedge position and/or “too distal” placement of the PAC balloon if (1) the body of the PAC is seen within the RVOT and (2) the PAC balloon is not seen in the MPA or RPA
	Optimise final PAC balloon position to distal MPA/proximal RPA
Post-insertion	Repetition of the above TTE signs to identify proximal or distal migration of the PAC from the initial insertion point
	When in doubt, confirmation of the PAC balloon inflation status by visualisation of the “to-and-fro” movement of the echogenic air-filled PAC balloon
	Quantify possible contribution of decline in RV/TV/PV function with presence of the PAC

TTE: Transthoracic echocardiogram; BMI: Body mass index; PAC: Pulmonary artery catheter; MPA: Main pulmonary artery; RPA: Right pulmonary artery; RV: Right ventricle; PA: Pulmonary artery; RVOT: Right ventricular outflow tract.