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Noninvasive Evaluation of Pulmonary Capillary Wedge Pressure by BP Response to the Valsalva Maneuver: BP

With the release of the strain, the intrathoracic pressure decreases abruptly with a further sudden drop in arterial pressure (phase 3). Thereafter, as a result of an increased venous return, the arterial pressure overshoots to levels above control with a widened pulse amplitude and a rise of stroke volume, while peripheral resistance remains transiently elevated (phase 4).> Figure 6 shows a normal hemodynamic response to the VM in one patient.
It has long been suggested that the BP response to the VM may be useful in evaluating left ventricular dysfunction. The normal drop of the systolic BP and the pulse amplitude during the VM are absent in heart failure patients with elevated cardiac filling pressures. www.canadian-familypharmacy.com Reading here In these patients, the increase in BP during phase 1 of the VM is followed by a plateau during phase 2 (ie, the square root response [Fig 7]), Gorlin et al showed that this abnormal response of the BP was consistently associated with an increased PCWP. In the presence of decreased venous return, the maintenance of left ventricular filling throughout the strain of the VM seems to be a prerequisite for this square-wave response.’’ This assumption is supported by the finding that left ventricular end-diastolic volume and left atrial dimension, as assessed by echocardiography, did not change during the VM in patients with CHF compared to healthy subjects. Accordingly, the BP response to the VM may be a clinically useful tool in detecting elevated left side filling pressure due to left ventricular dysfunction. Although the correlation between the PAR and the PCWP in this study explained only 75% of the variance of PCWP and, therefore, would not allow an exact prediction of PCWP in all cases, the sensitivity and specificity were high enough to predict the presence of an elevated PCWP in most patients.
Figure 6. Normal arterial pulse amplitude (PA) response during the VM in a patient with normal PCWP. During the straining phase (between the two vertical lines) of the VM, the systolic arterial BP (SBP) and the diastolic arterial BP (DBP) rise with the maintained pulse amplitude (phase 1) followed by an acute drop in BP and a narrowing of the pulse pressure amplitude with a compensatory rise in heart rate (HR) and peripheral vascular resistance (phase 2). With the release of the strain, a further sudden drop occurs in arterial pressure (phase 3). Thereafter, the arterial pressure overshoots to levels above control with a widened pulse amplitude (phase 4).
Figure 7. Abnormal arterial PA response during the VM in one patient with an elevated PCWP (ie, the square-wave response). During the straining phase of the VM (delimited by the two vertical lines) the SBP and the DBP rise with maintained pulse amplitude (phase 1), while there follows no drop in BP or narrowing of the pulse amplitude during phase 2. With the release of the strain, the arterial pressure drops suddenly to the pretest level (phase 3). The HR does not change. See the legend of Figure 6 for abbreviations that are not used in the text.