Is the pulmonary artery catheter useful from Best Practice by walterray

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									Is the pulmonary artery
    catheter useful?
   from Best Practice and Research clinical
 Anaesthesiology Vol. 19, No. I, pp97-110, 2005



                               by R3 黃信豪
                  Introduction
   More than 1.5 million PACs are used each year in
    the USA, and half of them are placed in high-risk
    trauma and surgical patients.
   Majority of clinicians believe that the information
    provided by PAC monitoring is useful in guiding
    therapy and improving outcomes despite no
    literature could prove it.
   This article will review and discuss the clinical
    utility, potential benefits, and harms of PAC, and
    provide recommendations for future research in
    this area.
Risks and harms of pulmonary
 artery catheterization (PAC)
   Insertion of a PAC result in morbidity associated
    with obtaining central venous access.
   A review article by Shah KB ( anesthesiology 2004;
    100: 1411-1418 ) showed low incidence of
    morbidity associated with this procedure.
   The complications associated with PAC
    insertion including:
1.hemorrhage or hematoma with airway compromise –
 more frequently with int. jugular approach.
Risks and harms of pulmonary
 artery catheterization (PAC)
2.pneumothorax and hemothorax –more frequently with
 subclavian approach.
3.air embolization or other embolization due to cath.
 fragments and carotid artery plaque after arterial
 puncture.
4.Horner’s syndrome due to adjacent structures damage.
5.thoracic duct injury.
6.brachial plexus injury.
7.transient phrenic nerve injury.
Risks and harms of pulmonary
 artery catheterization (PAC)
   The factors that were thought to reduce
    complication rates of PAC insertion:
1.experience
2.appropriate supervision
3.attention to detail
4.ultra-sound guided may reduce some
 complications especially in patients with difficult
 anatomy and in teaching situations.
Risks and harms of pulmonary
 artery catheterization (PAC)
   The primary concern during advancement of the
    PAC is the occurrence of arrhythmias.
   The complications related to the maintenance of
    PACs including:
1.thrombosis –commonly occurs
2.embolization –may due to balloon rupture
3.pulmonary infarction
4.pulmonary artery rupture –risk factors including old age,
    pulmonary hypertension, improper inflation.
5.infection –remove the PAC as soon as it is no longer needed, but no
    schedule replacement is suggest
    Information obtained by the
               PAC
   Clinical manifestations of serious underlying
    pathophysiology in critically ill patients often lag
    behind more subtle hemodynamic changes.
   PAC was initially designed to measure pulmonary
    a. pressure and pulmonary a. wedge pressure.
   Today, the information that could obtained from
    PAC including:
a. left ventricular end-diastolic pressure (LVEDP) –used as
  a surrogate to assess left ventricular preload
  Information obtained by the
             PAC
b. pulmonary capillary wedge pressure (PCWP) –used to
  indirectly estimate LVEDP.
c. pulmonary artery occluded pressure (PAOP) –use to
  estimate PCWP
d. pulmonary artery end-diastolic pressure (PAEDP) –used
  as an estimate of PCWP to avoid the potential for
  pulmonary infarction or pulmonary artery rupture.
e. right atrial pressure (RAP) –may provide information of
  right ventricular performance
f. cardiac output (CO) – may useful in the diagnosis of
  complex medical problems and assessing the response to
  therapeutic interventions.
  Information obtained by the
             PAC
g. continuous mixed venous oxygen saturation (SvO2) –
  assessment of global tissue oxygenation, which varies
  directly with CO, Hb, SaO2, and metabolic rate.
h. right ventricular ejection fraction (RVEF) –as a
  determinant of LV preload
i. right ventricular end-diastolic volume (RVEDV) and
  right ventricular end-diastolic volume index (RVEDVI) –
  was the best indicator of cardiac preload than PAOP,
  especially when patient receiving mechanical ventilation
  and PEEP (up to 50 cmH2O).
         Pulmonary artery
     catheterization and clinical
             outcomes
   Over 1500 articles and abstracts relating to PACs
    published between 1972 and 2002, but only 28 of
    these were controlled studies of the impact of PAC
    on clinical outcomes.
   Preoperative monitoring:
1.the role of PAC monitoring in hemodynamic optimization
  prior to high-risk surgery remains controversial.
2.two studies ( by Wilson J, BMJ 1999; and Boyd O, JAMA 1993)
  showed that the mortality rate reduced by 75% when the
  PAC was used to elevate oxygen delivery.
              Pulmonary artery
   catheterization and clinical
                      outcomes 1991; Valentine
3. but three studies (Brlauk JF, Annals of surgery
 RJ, Journal of Vascular Surgery 1998; Bender JS, Annals of surgery
 1997) showed no differences in perioperative mortality
 were observed.
4. However, preoperative tune-up by PAC resulted in
   a. fewer adverse intraoperative events
   b. less postoperative cardiac morbidity
   c. and less early graft thrombosis in the third study
           Pulmonary artery
   catheterization and clinical
                 outcomes
 Intra-operative monitoring:
Non-cardiac surgery
 1. In two groups of patient with previous MI, the incidence
  of re-infarction was significantly reduce in group with
  PAC used compared to control group. The authors
  suggested that aggressive hemodynamic monitoring was
  associate with improved outcomes in these patients. (Rao
  TLK, anesthesiology 1983).
 2. A threefold increase in the incidence of major post-
  operative cardiac events occurred in patients receiving
  PACs. (Polanczyk CA, JAMA 2001)
            Pulmonary artery
   catheterization and clinical
Cardiac surgery
                outcomes
1. The PAC-monitored patients had an increased
 postoperative weight gain and intubation times. (Stewart RD,
 The Annals of Thoracic surgery 1998)
2. In a study of patients with left main coronary artery
 disease, mortality was significantly less in subjects
 monitored with PAC compared to those monitored with
 CVP. (Moore CH, The Annals of Thoracic surgery 1978)
3. Patients undergoing CABG monitored with CVPs or
 PACs have no differences in major morbidity, mortality, or
 ICU length of stay. (Tuman KJ, Anesthesiology 1989)
 Pulmonary artery catheterization
           and clinical outcomes
Vascular surgery
1. The mortality rate was significantly increased in the
 patients with the abdominal aortic aneurysm at the
 hospital which routinely used PAC monitoring and
 inotropes. (Sandison AJ, European Journal of vascular and
 Endovascular surgery 1998)
2. A prospective cohort of 61 patients had a reduced
 incidence of renal dysfunction when fluid balance was
 monitored with a PAC when compared to a historical
 control group. (Hesdorffer CS, Clinical Nephrology 1987)
3. Two randomized trials in low-risk patients undergoing
 AAA surgery have been published. No significant
 differences were observed between the groups in morbidity,
 mortality, or hospital length of stay. (Isaacson IJ, Journal of
 vascular surgery 1990; Joyce WP, European Journal of Vascular
 Surgery 1990)
         Pulmonary artery
     catheterization and clinical
             outcomes
   Post-operative monitoring:
1. Two trials from the University of Hawaii
 randomized critically ill patients showed
 morbidity and mortality were not reduced in the
 treatment group. (Yu M, Critical Care Medicine 1993; Yu M,
    Critical Care Medicine 1995)
2. No differences in the number of dysfunctional
 organs, length of ICU stay, or mortality rate by a
 largest randomized clinical trial. (Gattinoni L, NEJM
    1995)
    Summary of evidence from
         clinical trials
   Despite three decades of use, there is still vigorous
    debate about the efficacy and utility of PACs
    during peri-operation.
   On the basis of evidence currently available, it is
    difficult to draw meaningful conclusions about the
    impact of PACs on morbidity or mortality.
   The interpretation of many clinical trials is
    significantly limited by important flaws in study
    design, including:
  Summary of evidence from
       clinical trials
1. Inadequate sample size
2. Lack of randomization
3. Lack of standardization of treatments or therapies based
 on PAC data
4. Uncertainty relating to ‘optimal’ hemodynamic values
 required to improve outcomes
5. Heterogeneity of patient populations enrolled in clinical
 trials
6. Lack of standardization of user knowledge
    Summary of evidence from
         clinical trials
There are three interrelated variables should be assessed
 in determining the appropriateness of PAC monitoring:
1. Patients should be examined for evidence of significant
 organ dysfunction that may increase the risk of
 hemodynamic disturbances
2. Major surgical procedures may be associated with
 hemodynamic disturbances that may damage organ
 systems
3. Benefits from PAC can be obtained only if the physicians
 and nurses using the PAC demonstrate competence in the
 basic technical and cognitive skills.
                  Conclusion
   The pulmonary artery catheter is an important tool
    in the quantitative assessment of cardiopulmonary
    function in the peri-operative period.
   PAC allows the clinician to determine several
    important hemodynamic indices, which potentially
    allows for prompt diagnostic assessment and
    therapeutic interventions.
   On the basis of currently available evidence, it is
    uncertain whether PAC improves, worsens, or has
    no effect on major outcomes in critical patients.
                  Conclusion
   Additional large-scale, randomized clinical trials,
    using protocols to define treatment endpoints, are
    needed to demonstrate the effectiveness of PACs.
   All care-givers must be skilled in the management
    of PACs and the interpretation of the data, and
    must employ the appropriate intervention for the
    patient in order to observe improved outcomes.

								
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