A high mean arterial pressure target is associated with improved microcirculation in septic shock patients with previous hypertension: a prospective open label study
Xu et al. Critical Care
A high mean arterial pressure target is associated with improved microcirculation in septic shock patients with previous hypertension: a prospective open label study
Jing-Yuan Xu 0
Si-Qing Ma 1
Chun Pan 0
Hong-Li He 0
Shi-Xia Cai 0
Shu-Ling Hu 0
Ai-Ran Liu 0
Ling Liu 0
Ying-Zi Huang 0
Feng-Mei Guo 0
Yi Yang 0
Hai-Bo Qiu 0
0 Department of Critical Care Medicine, Nanjing Zhongda Hospital, School of Medicine, Southeast University , Nanjing 210009 , P.R. China
1 Department of Critical Care Medicine, Qinghai Provincial People's Hospital , Xining 810000 , P.R. China
Introduction: The effect of mean arterial pressure titration to a higher level on microcirculation in septic shock patients with previous hypertension remains unknown. Our goal is to assess the effect of mean arterial pressure titration to a higher level on microcirculation in hypertensive septic shock patients. Methods: This is a single-center, open-label study. Hypertensive patients with septic shock for less than 24 hours after adequate fluid resuscitation and requiring norepinephrine to maintain a mean arterial pressure of 65 mmHg were enrolled. Mean arterial pressure was then titrated by norepinephrine from 65 mmHg to the normal level of the patient. In addition to hemodynamic variables, sublingual microcirculation was evaluated by sidestream dark field imaging. Results: Nineteen patients were enrolled in the study. Increasing mean arterial pressure from 65 mmHg to normal levels was associated with increased central venous pressure (from 11 4 to 13 4 mmHg, P = 0.002), cardiac output (from 5.4 1.4 to 6.4 2.1 l/minute, P = 0.001), and central venous oxygen saturation (from 81 7 to 83 7%, P = 0.001). There were significant increases in small perfused vessel density (from 10.96 2.98 to 11.99 2.55 vessels/mm2, P = 0.009), proportion of small perfused vessels (from 85 18 to 92 14%, P = 0.002), and small microvascular flow index (from 2.45 0.61 to 2.80 0.68, P = 0.009) when compared with a mean arterial pressure of 65 mmHg. Conclusions: Increasing mean arterial pressure from 65 mmHg to normal levels is associated with improved microcirculation in hypertensive septic shock patients.
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Introduction
Septic shock is a major cause of death in critically ill
patients and is characterized by hypotension and
hypoperfusion [1]. Although mortality has been reported to
be decreased due to the progress in therapy for septic
shock [2,3], microcirculation abnormalities can still be
present and contribute to hypoperfusion [4].
Microvascular dysfunction is associated with organ dysfunction and
mortality [5,6]; moreover, early improvement in the
microcirculation during resuscitation is associated with
reduced organ failure [7]. Therefore, therapeutic strategies
aimed at improving the microcirculation are warranted to
mitigate hypoperfusion and organ failure.
Maintaining sufficient perfusion pressure might be an
important way to improve the microcirculatory
perfusion [8]. As one of the key determinants of perfusion
pressure, adequate mean arterial pressure (MAP) might
reduce hypoperfusion and organ failure. Correa and
colleagues [9] have evaluated the effects of different MAP
targets in septic pigs, and show that targeting a MAP
between 50 and 60 mmHg in septic shock is associated
with increased incidence of acute kidney injury when
compared with a target MAP of between 75 and 85 mmHg.
Moreover, Badin and colleagues [10] have reported that
acute kidney injury is decreased with a MAP of at least
72 mmHg. However, which MAP levels should be targeted
to improve microcirculation remains controversial [11-13].
The optimal MAP target in septic shock patients,
especially in patients with previous hypertension, is still
unknown [14]. The guidelines [15] for treating septic
shock have recommended that MAP should be
maintained at a level of at least 65 mmHg, and emphasized a
higher blood pressure for patients with previous
hypertension. A recent published randomized controlled study
[16] has shown no difference in mortality in septic shock
patients undergoing resuscitation with a high MAP target
or a low MAP target. However, among chronic
hypertensive patients, those in the high-target group require less
renal replacement therapy, indicating that septic shock
patients with chronic hypertension might need higher MAP
to maintain microcirculation.
Our goal was to assess the effect on the
microcirculation of MAP titration to normal levels in septic shock
patients with previous hypertension. We hypothesized
that the increase in MAP from 65 mmHg to the normal
levels of patients is associated with improved sublingual
microcirculation.
Materials and methods
Setting
This was a single-center, prospective, open-label study
conducted in the intensive care unit of a tertiary care
teaching hospital. The study protocol was approved by the
Ethics Committee (Approval Number: 2011ZDllKY03.0)
of Zhongda Hospital, School of Medicine, Southeast
University, (...truncated)