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Pulmonary Artery Catheter (PAC)
Overview
- Routine PAC use in general intensive care units has declined since the PAC-Man (2005) and ESCAPE (2006) trials showed no mortality benefit in heterogeneous critically ill cohorts. Contemporary observational work, however, indicates improved outcomes when PACs are targeted to cardiogenic shock, advanced heart failure, pulmonary hypertension and complex cardiac surgery. The device remains the only bedside technology that simultaneously provides continuous cardiac output (CO), right-sided pressures and mixed venous oxygen saturation (SvO₂).
Current Indications (Adults)
| Domain | Specific scenarios | Rationale |
|---|---|---|
| Cardiovascular shock | Refractory cardiogenic or mixed shock, VA-ECMO weaning | Guides inotrope/vasopressor selection, RV afterload reduction |
| Advanced heart failure | Pre-transplant assessment, LVAD optimisation | Optimises PVR and filling pressures |
| Pulmonary hypertension | Perioperative risk stratification, targeted pulmonary vasodilators | Direct PA pressure measurements |
| High-risk surgery | Complex valve, combined CABG + LV aneurysm repair, lung/ liver transplantation | Trend SvO₂ & CO during massive shifts |
| Shunt quantification | Unexplained hypoxaemia, intracardiac shunt suspicion | Calculates Qp:Qs ratio |
- Where equally effective non-invasive monitors (e.g. TOE, pulse-contour analysis) are available, choose the least invasive option that answers the clinical question.
Contra-indications
- Absolute: Prosthetic tricuspid / pulmonic valve, right-sided endocarditis or mass, severe tricuspid stenosis, chronic thrombo-embolic pulmonary hypertension with large PA thrombus.
- Relative: Left bundle branch block, coagulopathy (platelets < 50 × 10⁹ L⁻¹ or INR > 2), severe arrhythmia history, distorted right heart anatomy (e.g. Ebstein anomaly).
Catheter Generations & Features
| Generation | Key features | Typical French size |
|---|---|---|
| 1st-gen | Intermittent thermodilution CO | 7.0–7.5 |
| 2nd-gen | Continuous CO (heating filament), SvO₂ oximetry | 7.5–8.0 |
| 3rd-gen | RV ejection fraction & end-diastolic volume, pacing tip, fibre-optic oximetry | 8.0+ |
- All modern PACs have ≥ 4 lumens, 1.5 mL balloon, 110 cm length with 10 cm markings.
Insertion Essentials
- Ultrasound-guided introducer (8 Fr) via right IJ preferred; femoral access increases infection and thrombosis.
- Zero and level at mid-thoracic line; flush all lumens.
- Advance to RA waveform (15–20 cm IJ), inflate balloon (≤1.5 mL air).
- Follow sequential waveforms: RV (25/5 mm Hg), PA (25/10 mm Hg, dicrotic notch), wedge (6–12 mm Hg).
- Deflate balloon promptly; confirm tip in West Zone III (TOE, fluoroscopy or CXR).
- Daily chest radiography is unnecessary unless clinical change occurs; document balloon inflation volume and keep syringe locked.
Haemodynamic Variables
| Directly measured | Normal range | Derived (selected) | Formula |
|---|---|---|---|
| RAP / CVP | 2–6 mm Hg | SVR | (MAP–RAP) × 80 / CO |
| PAP | 25/10 mm Hg | PVR | (mPAP–PCWP) × 80 / CO |
| PCWP | 6–12 mm Hg | SV | CO / HR × 1000 |
| CO / CI | 4–8 L min⁻¹ / 2.5–4 L min⁻¹ m⁻² | O₂ delivery (DO₂) | CI × (CaO₂ × 10) |
| SvO₂ | 65–75 % | Qp:Qs | (SaO₂–SvO₂) / (PvO₂–PaO₂) |
Cardiac Output Techniques
- Intermittent thermodilution: 10 mL iced (<8 °C) or room-temperature saline bolus at end-expiration × 3; average values. Avoid in severe TR (over-estimates CO).
- Continuous CO: Heating filament pulses every 30–60 s with sliding-window averaging—responds slowly (3–5 min) to abrupt haemodynamic changes.
Mixed Venous Oxygen Saturation (SvO₂)
- Reflects global balance of oxygen delivery and demand.
- Low SvO₂ (<60 %): inadequate CO, anaemia, hypoxaemia, hyper-metabolism.
- High SvO₂ (>75 %): sepsis, left-to-right shunt, mitochondrial dysfunction, excessive FiO₂.
- Trend rather than single reading; always interpret with haemodynamics and lactate.
Complications (incidence) and Mitigation
| Complication | Rate | Prevention |
|---|---|---|
| Dysrhythmia (PVCs, VT) | 60 % transient | Paediatric ECG lead guidance, slow advancement |
| RBBB / complete heart block in prior LBBB | 1 % | Monitor ECG continuously; have pacing kit ready |
| PA rupture | <0.1 % (mortality 50 %) | Keep balloon <1.5 mL, avoid distal wedge, limit inflations |
| Infection / CRBSI | 1–3 % day⁻¹ | Maximal sterile barrier, remove when no longer essential |
| Thrombosis / pulmonary infarct | 1–2 % | Heparinised flush, daily necessity review |
Evidence & Outcomes
- Meta-analysis of 15 000 cardiogenic shock cases (2023) showed PAC use associated with lower in-hospital mortality in acute decompensated heart failure but not in post-MI shock.
- Large US and Canadian registry data (2022-2024) confirm survival benefit when PAC is integrated into structured shock algorithms with team-based escalation pathways.
- No mortality or length-of-stay benefit in unselected sepsis or ARDS; echocardiography and pulse-contour devices preferred.
- Environmental impact: disposable plastic mass ≈ 150 g; choose less invasive monitors when information gain is marginal.
1Practical Recommendations
- Select a monitoring modality that directly answers the management question; default to TOE or calibrated arterial pulse-contour first
- Use PAC when: refractory or complex shock, biventricular dysfunction, planned heart transplant, severe pulmonary hypertension, or when non-invasive data conflict.
- Calibrate and correlate: cross-check thermodilution CO with echo; repeat after major interventions.
- Review daily: remove PAC once haemodynamics stable and management decisions no longer depend on wedge pressure or SvO₂ trends.
Links
- Central venous pressure (CVP)
- CVS support and shock
- Pulmonary Hypertension
- Transplants and organ donation
References:
- Senoner T, Velik-Salchner C, Tauber H. The Pulmonary Artery Catheter in the Perioperative Setting: Should It Still Be Used? Diagnostics (Basel). 2022 Jan 12;12(1):177. doi: 10.3390/diagnostics12010177. PMID: 35054343; PMCID: PMC8774775.
- Harvey S, et al. PAC-Man trial. Lancet 2005;365:478-485
- Swanick CJ, et al. Pulmonary artery catheter use in cardiogenic shock: registry analysis. JACC Heart Fail 2023;11:923-934. jacc.org
- Nirmalan M, Baldwin Z. Do pulmonary artery catheters have a role in the 21st century? Br J Anaesth 2022;129:645-651. bjanaesthesia.org
- Lee J, et al. Effectiveness of PAC monitoring for cardiogenic shock: systematic review & meta-analysis. J Thorac Dis 2023;15:1115-1123. pubmed.ncbi.nlm.nih.gov
- Smit M. Physical principles enabling cardiac output monitoring. SAJAA 2023;29:198-205. sajaa.co.za
- Hall R, et al. Classification of pulmonary artery catheters. Br J Anaesth 2023;131:1108-1115. bjanaesthesia.org
- 2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass monitoring. Br J Anaesth 2025;134:157-190. bjanaesthesia.org
- Hiemstra B, et al. Sustainable haemodynamic monitoring. Br J Anaesth 2024;133:22-30. bjanaesthesia.org
Summaries:
Pulmonary artery catheter-video
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