- Criada: 17-02-22
- Último login: 17-02-22
- string: 342342342
Perfil do usuário
34hs603
Intraoperative Invasive Blood Pressure Monitoring and the Potential Pitfalls
Invasive intraarterial blood pressure measurement is currently the gold standard for intraoperative hemodynamic
monitoring but accurate systolic blood pressure (SBP) measurement is difficult in everyday clinical practice, mostly because
of problems with hyper-resonance or damping within the measurement system, which can lead to erroneous treatment decisions if
these phenomena are not recognized. A hyper-resonant blood pressure trace significantly overestimates true systolic blood
pressure while underestimating the diastolic pressure. Invasively measured systolic blood pressure is also significantly more
affected than mean blood pressure by the site of measurement within the arterial system. Patients in the intraoperative
period should be treated based on the invasively measured mean blood pressure rather than the systolic blood pressure. In
this review, we discuss the pros/cons, mechanisms of Disposable
IBP Transducers, and the interpretation of the invasively measured systolic blood pressure value.
Introduction & Background
Disposable IBP
Transducer Kit-Single Channel is the gold standard of arterial pressure measurement in 10-20% of high-risk patients [1
-2]. In the remaining 80%-90% of surgical patients, the standard intermittent non-invasive blood pressure (BP) that is
obtained using oscillometry with a brachial cuff has been shown to have only poor agreement with IBP in critically ill
patients [3-4]. These observed measurement differences are clinically significant because they would have triggered a change
in treatment in as many as 20% of the critical care patients. Non-invasive oscillometric BP measurement with a brachial cuff
tends to, on average, overestimate BP during hypotension and underestimate BP during hypertension, with a significant bias
and considerable scatter. Invasive BP measurement with an arterial catheter, providing continuous BP measurements, detected
nearly twice as many episodes of hypotension as intermittent oscillometric measurements with a brachial cuff [5]. Continuous
rather than intermittent hemodynamic monitoring is highly desirable in high-risk patients. Even when continuous BP monitoring
was accomplished in medium-risk patients with non-invasive techniques, the number of episodes of intraoperative hypotension
was still reduced by half when compared to intermittent monitoring with a brachial cuff [6]. Although non-invasive continuous
monitoring has fewer complications than arterial cannulation, it has not yet Disposable IBP Transducer Kit-Double Channel as the gold
standard in high-risk patients, but rather serves as an alternative in low and medium-risk patients where IBP measurements
are not warranted [7].
An adequate blood pressure level is a means to achieve the ultimate goal of the circulation, which is adequate end-organ
perfusion and tissue oxygenation. Adequate organ perfusion is mostly regulated locally, in the organs, by changing the local
vascular resistance, which, when seen over multiple organs and the entire circulation, works as a re-distribution of the
total flow or cardiac output (CO) [8]. In addition, the total flow or CO is also regulated centrally if this re-distribution
is not enough. The local flow control via regulation of resistance of the arterioles only functions properly under the
condition of adequate perfusion pressure, in which the mean systemic arterial pressure plays a central role. Continuous
monitoring of local organ circulation, global flow, or CO and arterial pressure is, therefore, the key. Monitoring the
microcirculation has been shown to be useful when determining the optimal BP range that is associated with adequate
regulation of local blood flow and tissue oxygenation for an individual patient [9-10]. Pulse contour analysis provides a
means of assessing global flow or CO because it has long been recognized that an apparently adequate BP level may not
necessarily be associated with an adequate total blood flow to all the tissues [11-12]. Different organs have a different
range of perfusion pressures that allow for adequate local control of organ flow. While the coronary circulation can increase
flow fivefold as long as heart rate is maintained at 70 bpm, diastolic arterial pressure is maintained at adequate levels and
coronary obstructive lesions are absent, the kidney is much more sensitive to decreases in perfusion pressure [13]. The
average lower limit of cerebral blood flow autoregulation in normotensive adult humans is around a mean arterial pressure
(MAP) of 70 mmHg [14]. Hence, the heart has a greater range of adequate perfusion pressures than both the brain and the
kidneys. Blood pressure goals as adequate perfusion pressure ranges, therefore, need to be specifically determined and
adjusted for every individual clinical situation by considering the patient’s specific comorbidities as well as the planned
surgical procedure.
Blood pressure and surgical outcomes
Although the real target is adequate total blood flow and adequate local flow to individual organs, most outcome data are
available for blood pressure. Hypotension has been associated with increased postoperative morbidity. Even short durations of
intraoperative MAP less than 55 mmHg are associated with myocardial injury and acute kidney injury (AKI) [15]. A
perioperative quality initiative consensus statement also concluded that even brief durations of systolic arterial pressure
Invasive intraarterial blood pressure measurement is currently the gold standard for intraoperative hemodynamic
monitoring but accurate systolic blood pressure (SBP) measurement is difficult in everyday clinical practice, mostly because
of problems with hyper-resonance or damping within the measurement system, which can lead to erroneous treatment decisions if
these phenomena are not recognized. A hyper-resonant blood pressure trace significantly overestimates true systolic blood
pressure while underestimating the diastolic pressure. Invasively measured systolic blood pressure is also significantly more
affected than mean blood pressure by the site of measurement within the arterial system. Patients in the intraoperative
period should be treated based on the invasively measured mean blood pressure rather than the systolic blood pressure. In
this review, we discuss the pros/cons, mechanisms of Disposable
IBP Transducers, and the interpretation of the invasively measured systolic blood pressure value.
Introduction & Background
Disposable IBP
Transducer Kit-Single Channel is the gold standard of arterial pressure measurement in 10-20% of high-risk patients [1
-2]. In the remaining 80%-90% of surgical patients, the standard intermittent non-invasive blood pressure (BP) that is
obtained using oscillometry with a brachial cuff has been shown to have only poor agreement with IBP in critically ill
patients [3-4]. These observed measurement differences are clinically significant because they would have triggered a change
in treatment in as many as 20% of the critical care patients. Non-invasive oscillometric BP measurement with a brachial cuff
tends to, on average, overestimate BP during hypotension and underestimate BP during hypertension, with a significant bias
and considerable scatter. Invasive BP measurement with an arterial catheter, providing continuous BP measurements, detected
nearly twice as many episodes of hypotension as intermittent oscillometric measurements with a brachial cuff [5]. Continuous
rather than intermittent hemodynamic monitoring is highly desirable in high-risk patients. Even when continuous BP monitoring
was accomplished in medium-risk patients with non-invasive techniques, the number of episodes of intraoperative hypotension
was still reduced by half when compared to intermittent monitoring with a brachial cuff [6]. Although non-invasive continuous
monitoring has fewer complications than arterial cannulation, it has not yet Disposable IBP Transducer Kit-Double Channel as the gold
standard in high-risk patients, but rather serves as an alternative in low and medium-risk patients where IBP measurements
are not warranted [7].
An adequate blood pressure level is a means to achieve the ultimate goal of the circulation, which is adequate end-organ
perfusion and tissue oxygenation. Adequate organ perfusion is mostly regulated locally, in the organs, by changing the local
vascular resistance, which, when seen over multiple organs and the entire circulation, works as a re-distribution of the
total flow or cardiac output (CO) [8]. In addition, the total flow or CO is also regulated centrally if this re-distribution
is not enough. The local flow control via regulation of resistance of the arterioles only functions properly under the
condition of adequate perfusion pressure, in which the mean systemic arterial pressure plays a central role. Continuous
monitoring of local organ circulation, global flow, or CO and arterial pressure is, therefore, the key. Monitoring the
microcirculation has been shown to be useful when determining the optimal BP range that is associated with adequate
regulation of local blood flow and tissue oxygenation for an individual patient [9-10]. Pulse contour analysis provides a
means of assessing global flow or CO because it has long been recognized that an apparently adequate BP level may not
necessarily be associated with an adequate total blood flow to all the tissues [11-12]. Different organs have a different
range of perfusion pressures that allow for adequate local control of organ flow. While the coronary circulation can increase
flow fivefold as long as heart rate is maintained at 70 bpm, diastolic arterial pressure is maintained at adequate levels and
coronary obstructive lesions are absent, the kidney is much more sensitive to decreases in perfusion pressure [13]. The
average lower limit of cerebral blood flow autoregulation in normotensive adult humans is around a mean arterial pressure
(MAP) of 70 mmHg [14]. Hence, the heart has a greater range of adequate perfusion pressures than both the brain and the
kidneys. Blood pressure goals as adequate perfusion pressure ranges, therefore, need to be specifically determined and
adjusted for every individual clinical situation by considering the patient’s specific comorbidities as well as the planned
surgical procedure.
Blood pressure and surgical outcomes
Although the real target is adequate total blood flow and adequate local flow to individual organs, most outcome data are
available for blood pressure. Hypotension has been associated with increased postoperative morbidity. Even short durations of
intraoperative MAP less than 55 mmHg are associated with myocardial injury and acute kidney injury (AKI) [15]. A
perioperative quality initiative consensus statement also concluded that even brief durations of systolic arterial pressure