None listed
Conditions
Brief summary
Shock is a medical emergency in which the organs and tissues of the body are not receiving adequate blood flow. Preventing low blood pressure (or hypotension) in such patients is an integral part of standard treatment, but it is unclear what degree of hypotension in relation to patients’ usual resting/basal blood pressure (basal-BP) should be treated. In our pilot study, we reported that in usual practice, the achieved-BP for shocked patients in intensive care unit (ICU) was generally lower and often unrelated to their basal-BP. It resulted in varying degree of untreated relative hypotension (BP-deficit) that was associated with an increased risk of acute kidney injury (AKI). The main purpose of this study is to test or confirm these findings in a broader clinical practice. Further, the novel data on both degree and duration of relative hypotension accepted in routine care in a broad multicentre setting would be crucial to design a major interventional trial. Our hypothesis for this study is that some degree of relative hypotension, quantified as mean perfusion pressure deficit (MPP-deficit), would be common in routine care for vasopressor-treated patients. In critically ill patients, who often have blunted autoregulation, a persisting MPP-deficit may fail to restore adequate renal perfusion that may result in worsening kidney function. We hypothesize that such MPP-deficit, a measure of untreated relative hypotension, in patients with shock during vasopressor therapy is associated with an increased risk of new-onset AKI. The association between study exposure variables and outcome measures will be adjusted for pre-specified covariates in a multivariate model.
Interventions
The primary exposure variable of ‘relative hypotensive load’ will be measured as the mean perfusion pressure (MPP) deficit during 120 vasopressor-hours in ICU. MPP-deficit will be derived as the percentage difference between the patient's pre-morbid basal-MPP and the achieved-MPP in ICU in relation to basal-MPP. Achieved-MPP will be recorded each hour in ICU until a patient is weaned off vasopressor for at least 24 hours or up to a maximum of 120 hours, whichever is earlier.
The secondary expo
The primary exposure variable of ‘relative hypotensive load’ will be measured as the mean perfusion pressure (MPP) deficit during 120 vasopressor-hours in ICU. MPP-deficit will be derived as the percentage difference between the patient's pre-morbid basal-MPP and the achieved-MPP in ICU in relation to basal-MPP. Achieved-MPP will be recorded each hour in ICU until a patient is weaned off vasopressor for at least 24 hours or up to a maximum of 120 hours, whichever is earlier. The secondary exposure variable is the percentage of vasopressor-hours spent at >20% MPP-deficit. We chose the threshold of 20% as it is considered as a clinically significant drop in blood pressure according to previous studies.
Sponsors
John Hunter Hospital
Eligibility
Sex/Gender
All
Age
40 Years to No maximum
Healthy volunteers
No
Inclusion criteria
a. ICU patients aged at least 40 yrs b. Trauma is not the main reason for the current ICU admission c. The patient is within 48 hours of ICU admission d. Patient has a central venous catheter (CVC) in situ or the placement of a CVC is imminent (within the next hour) as part of routine ICU management. e. The patient is receiving positive pressure ventilation (PPV) or the treating clinician anticipates the need for PPV (includes invasive or non-invasive ventilation or the use of high-flow oxygen) f. Shock, defined as clinician-initiated vasopressor therapy for at least 4 hours or more AND supported by any of the following within last 24 hours: 1) Lactate > or =2 mmol/l, or base deficit > or =3 mmol/l, 2) Central venous oxygen saturation (ScvO2) < or =60% 3) Creatinine increase by >44 micromol/l 4) Urine output <0.5 ml/kg/h or <40 ml/h for 2 hours
Exclusion criteria
a. Patients who are moribund, or deemed to have life expectancy of less than 6 months. b. Patients with renal failure requiring RRT, or in imminent need of RRT within the next 12 hours in the opinion of treating clinician or increase in serum creatinine of >350 micromol/l c. End stage renal disease d. Patients on extracorporeal support (ECMO, IABP, VAD). e. Patient has already been included in the study. f. Pregnancy, if known g. Active bleeding (clinical suspicion or requiring 3 or more packed red blood cells within 24 hours) h. Potential contraindications to either higher or lower BP targets (including but not limited to) 1) Cerebral perfusion pressure guided therapy e.g. intracranial hemorrhage or subarachnoid hemorrhage or traumatic brain injury 2) Abdominal perfusion pressure guided therapy 3) Aortic injury (e.g. dissection or post-operative) 4) Post cardiac surgery 5) Any other condition requiring higher or lower BP target specifically
Outcome results
None listed