Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine Read Online Free PDF Page A

BMI goal 18.5–24.9 kg/m 2
• Influenza vaccination ( Circ 2006;114:1549); screen for depression

PA CATHETER AND TAILORED THERAPY
    Rationale
• Cardiac output (CO) = SV × HR; SV depends on LV end-diastolic volume (LVEDV)
∴ manipulate LVEDV to optimize CO while minimizing pulmonary edema • Balloon at tip of catheter inflated → floats into “wedge” position. Column of blood extends from tip of catheter, through pulmonary circulation, to a point just proximal to LA. Under conditions of no flow, PCWPLA pressureLVEDP, which is proportional to LVEDV.
• Situations in which these basic assumptions fail:
(1) Catheter tip not in West lung zone 3 (and ∴ PCWP = alveolar pressure ≠ LA pressure); clues include lack of a & v waves and if PA diastolic pressure < PCWP
(2) PCWP > LA pressure (eg, mediastinal fibrosis, pulmonary VOD, PV stenosis)
(3) Mean LA pressure > LVEDP (eg, MR, MS)
(4) Δ LVEDP-LVEDV relationship (ie, abnl compliance, ∴ “nl” LVEDP may not be optimal)
    Indications (  JACC 1998;32:840 & Circ 2009;119:e391)
• Diagnosis and evaluation
Ddx of shock (cardiogenic vs. distributive; esp. if trial of IVF failed or is high risk) and of pulmonary edema (cardiogenic vs. not; esp. if trial of diuretic failed or is high risk)
Evaluation of CO, intracardiac shunt, pulmonary HTN, MR, tamponade
Evaluation of unexplained dyspnea (PAC during provocation w/ exercise, vasodilator)
• Therapeutics ( Circ 2006;113:1020)
Tailored therapy to optimize PCWP, SV, S v O 2 in heart failure (incl end-stage) or shock
Guide to vasodilator therapy (eg, inhaled NO, nifedipine) in pulm HTN, RV infarction
Guide to perioperative management in some high-risk Pts, pretransplantation
• Contraindications
Absolute : right-sided endocarditis, thrombus/mass or mechanical valve; PE
Relative : coagulopathy (reverse), recent PPM or ICD (place under fluoroscopy), LBBB (~5% risk of RBBB → CHB, place under fluoro), bioprosthetic R-sided valve
    Efficacy concerns ( NEJM 2006;354:2213; JAMA 2005;294:1664)
• No benefit to routine PAC use in high-risk surgery, sepsis, ARDS
• No benefit in decompensated HF (  JAMA 2005;294:1625); untested in cardiogenic shock • But: ~½ of CO & PCWP clinical estimates incorrect; CVP & PCWP not well correl.; ∴ use PAC to (a) answer hemodynamic ? and then remove, or (b) manage cardiogenic shock Placement
• Insertion site: R internal jugular or L subclavian veins for “anatomic” flotation into PA • Inflate balloon (max 1.5 mL) when advancing and to measure PCWP
• Use resistance to inflation and pressure tracing to avoid overinflation & risk of PA rupture • Deflate the balloon when withdrawing and at all other times • CXR should be obtained after placement to assess for catheter position and PTX
• If catheter cannot be successfully floated (typically if severe TR or RV dilatation) or if another relative contraindication exists, consider fluoroscopic guidance Complications
• Central venous access : pneumo/hemothorax (~1%), arterial puncture (if inadvertent cannulation w/ dilation → surgical/endovasc eval), air embolism, thoracic duct injury • Advancement : atrial or ventricular arrhythmias (3% VT; 20% NSVT and >50% PVC), RBBB (5%), catheter knotting, cardiac perforation/tamponade, PA rupture • Maintenance : infection (esp. if catheter >3 d old), thrombus, pulm infarction (≤1%), valve/chordae damage, PA rupture/pseudoaneurysm (esp. w/ PHT), balloon rupture Intracardiac pressures
• Transmural pressure (preload) = measured intracardiac pressure – intrathoracic pressure • Intrathoracic pressure (usually slightly) is transmitted to vessels and heart • Always measure intracardiac pressure at end-expiration , when intrathoracic pressure closest to 0 (“high point” in spont. breathing Pts; “low point” in Pts onpressure vent.) • If ↑ intrathoracic pressure (eg, PEEP), measured PCWP overestimates true transmural pressures. Can approx by subtracting ~½ PEEP (× ¾