Pulmonary Artery Catheterisation

Contraindications

• Absolute
  • Right sided endocarditis
  • Right sided masses (e.g. myxoma) or thrombi
• Relative
  • Severe coagulopathy
  • Severe thrombocytopaenia
• Reasons for caution
  • Tricuspid regurgitation - difficult passage of catheter
  • Left bundle branch block - catheter passage may induce complete heart block ⇒ be prepared to place a transvenous pacemaker should this occur

Method

Complications

• Pulmonary artery perforation
  • Risk factors
    • Older age
    • Prolonged balloon inflation
    • Pulmonary hypertension
    • Anticoagulation
  • Clinical features
    • Haemoptysis
    • Hypoxaemia
    • Shock
  • Management
    • Inflate the balloon
    • Intubate the patient with a dual-lumen endotracheal tube
    • Lateral decubitus position with affected side down
    • Emergency consultation with cardiothoracic surgeon and interventional radiology

Calculations

• Fick equation where:
  • $\text{CO}$ is the cardiac output (L) which is normally 4.8 - 7.3 L
  • $\dot{V}\mathrm{O}{}_2$ is the oxygen consumption (mL/min)
  • $C_{\text{a}}$ is the oxygen content of arterial blood (mL/L)
  • $C_{\text{v}}$ is the oxygen content of venous blood (mL/L)

$$\text{CO}=\frac{\dot{V}\mathrm{O}{}_2}{C_{\text{a}}-C_{\text{v}}}=\frac{\dot{V}\mathrm{O}{}_2}{1.36\times \text{Hb}\times (S_{\text{a}}\mathrm{O}{}_2-S_{\text{v}}\mathrm{O}{}_2)\times 10}$$

• Cardiac index equation where:
  • $\text{CI}$ is the cardiac index (L/min m^2) which is normally 2.8 - 4.2 L
  • $\text{BSA}$ is the body surface area (m^2)

$$\text{CI}=\frac{\text{CO}}{\text{BSA}}$$

• Systemic vascular resistance where:
  • $\text{SVR}$ is the systemic vascular resistance (dyn sec/cm^5) which is normally 700 - 1600
  • $\text{MAP}$ is the mean arterial pressure (mmHg)
  • $\text{RA}$ is the right atrial mean pressure (mmHg)
  • $\text{CO}$ is the cardiac output (L)

$$\text{SVR}=\frac{\text{MAP}-\text{RA}}{\text{CO}}\times 80$$

• Pulmonary vascular resistance where:
  • $\text{PVR}$ is the pulmonary vascular resistance (dyn sec/cm^5) which is normally 20 - 130
  • $\text{PA}$ is the pulmonary artery mean pressure (mmHg)
  • $\text{PCWP}$ is the pulmonary capillary wedge pressure (mmHg)
  • $\text{CO}$ is the cardiac output (L)

$$\text{PVR}=\frac{\text{PA}-\text{PCWP}}{\text{CO}}\times 80$$

• The above calculations can differentiate the type of Shock:

Sources

• Kelly, C.R., Rabbani, L.E., 2013. Pulmonary-Artery Catheterization. New England Journal of Medicine 369, e35. https://doi.org/10.1056/NEJMvcm1212416