Hypotension and Shock Clinical Trial
Official title:
Can Non Invasive Methods for Fluid Responsive Assessment Optimize Preventive Volemic Repletion in Order to Prevent Significant Hypotension After Spinal Anesthesia? A Randomized Trial
Spinal anesthesia is still the regional anesthesia technique most widely employed in everyday
clinical practice.
The most feared and common of its well known side effects consist in an abrupt reduction of
systemic vascular resistances, with consequence risk of systemic hypotension. To prevent this
potentially severe complication, an adequate correction of patients' volume status through a
preventive administration of fluids is widely used.
However this volume repletion is commonly accomplished on an empirical basis, without having
a real insight of patient hemodynamic status, carrying the risk of possible volume overload.
Aim of the study is to test the clinical impact of two simple, non-invasive methods to guide
volemic repletion before spinal anesthesia on the reduction of significant hypotension rate,
compared to empirical fluid administration.
The resulting high density of the anesthetic block and the reproducibility of the technique
have made of spinal anesthesia the most widely diffused regional anesthesia technique.
Nevertheless the procedure still remains the regional anesthesia technique burdened by the
potentially most severe side effects, the most frequent of which being systemic arterial
hypotension.
Subarachnoidal administration of local anesthetics in fact is associated not only with both a
motor and sensory block, but also with a blockade of the autonomic nervous system, which
controls peripheral vascular tone. Sympathetic block leads to a sudden decrease in peripheral
resistance, with consequent significant increase in vascular bed and relative hypovolemia.
Transient hypotensive episodes can be generally well tolerated by healthy patients, however
they may lead to major complications in patients with increased cardiovascular risk. In the
common clinical practice, it is usual to administer fluids empirically. An empirical
preventive fluid repletion however can represent per se a risk in patients with impaired
cardiac and renal functions, since a volume overload of heart chambers with reduced
compliance can cause pulmonary edema or congestive heart failure.
Since about ten years both non-invasive and invasive techniques have been developed, with the
specific purpose of optimizing fluid status on a rational basis. This methods are based on
the correlation between the levels of mean arterial pressure (MAP), systemic vascular
resistance (SVR) and cardiac output (CO), according to the equation: MAP = CO * SVR. The
latter explains why, in case of vasodilation, unless CO is increased, a lowering of SVR will
inevitably translate into a decrease of MAP.
Determinants of blood pressure are:
1. volemic status;
2. vascular resistance (determined by the control of the sympathetic system);
3. cardiac output.
In case of spinal anesthesia the reduction in SVR determines relative hypovolemia (due to an
increase in total vascular bed). For this reason after spinal anesthesia appears fundamental
an optimization of patients' volemic status through administration of fluids (eventually
associated with the administration of amines, in order to contrast massive vasodilation).
The use of methods to assess fluid responsiveness has been extensively studied in critical
patients populations. However these techniques have not been studied yet in non critical
patients. Spinal anesthesia is a model of pharmacological vasodilation which often generates
significant hypotension, for which nowadays an evidence-based rational treatment based on a
guided volemic repletion is still lacking.
WORKING HYPOTHESIS:
The use of non-invasive methods that have proven to be accurate for the identification of
patient fluid-responsiveness is currently not validated in patients undergoing spinal
anesthesia.
Ultrasound of inferior vena cava by is an effective method to determine the responsiveness to
fluids in a patient on mechanical ventilation, however it has been proven to be inaccurate in
spontaneous ventilating patients in critically ill patients, few data being available in non
critical patients. The study of the inferior vena cava is based on the size of the inferior
vena cava in its intra-abdominal portion (approximately 2 cm from emergency right atrium) and
the pattern of its diameter changes with breathing. This measurement is obtained with M-mode
ultrasound through subcostal view..
Passive leg raising test (PLRT) has been proven to be a highly accurate method in predicting
fluid responsiveness in spontaneously breathing patients, in a population of critically ill
patients. The method is based on the following assumption: active legs elevation, in addition
to its effect of venous pool shifting from the lower limbs to the thorax, exerts a
contemporary effect of stimulation on the peri-arterial sympathetic system at iliac-femoral
level, this causing an orthosympathetic reflex which can increase cardiac output, possibly
masking hypovolemia. Passive lower limbs raising instead has the advantage of mobilizing
lower limbs venous blood (estimated 300-500 ml), without activating the orthosympathetic
reflex. This allows for a quantification of the clinical response to a bolus of fluids, in
terms of decrease of blood pressure variations following leg raising.
The hypothesis that investigators want to test is that the use of inferior vena cava
ultrasound before spinal anesthesia, compared to the standard method (empirical fluid
administration) and a non-invasive method (PLRT) can reduce the impact of systemic
hypotension through an adequate titrated volemic repletion, avoiding both hypotension and
fluid overload. The final purpose is to ensure spinal anesthesia in the safest possible way.
OBJECTIVES OF THE STUDY:
Aim of the study is to determine whether vena cava ultrasound, a bedside, unexpensive, non
invasive methods, which have been tested as predictors of fluid responsiveness in critical
patients, is effective in guiding titrated fluid repletion in a non critical population, in
order both to decrease post procedural significant hypotension rate and unnecessary fluid
overload in patients undergoing spinal anesthesia for elective surgical procedures.
;
Status | Clinical Trial | Phase | |
---|---|---|---|
Recruiting |
NCT02782819 -
A Comparison of Crystalloid Alone Versus Crystalloid Plus Colloid in Shock Resuscitation
|
N/A | |
Completed |
NCT06121115 -
Norepinephrine Administration Through a Midline Catheter in an Intermediate Care Unit
|
||
Terminated |
NCT04538079 -
Non-invasive Objective Assessment of Hemodynamics in Preterm Neonates
|
||
Completed |
NCT03701646 -
ClearSight Validation in Pediatrics
|
||
Completed |
NCT04891380 -
BCG Biosensor and Non- and Invasive Monitoring During Emergency Medicine Cases, a Prospective Feasibility Study
|
N/A | |
Completed |
NCT03927066 -
Physiological Validation of Current Machine Learning Models for Hemodynamic Instability in Humans
|
N/A | |
Recruiting |
NCT04760977 -
Prehospital Management of Hypotensive Trauma in HEMS
|
||
Completed |
NCT03582501 -
Measurement of Hemodynamic Responses to Lower Body Negative Pressure
|
N/A | |
Terminated |
NCT03407287 -
Peripheral Venous Analysis (PIVA) for Predicting Volume Responsiveness and Fluid Status
|
||
Active, not recruiting |
NCT04688450 -
BP Management System User Acceptance Testing
|
N/A | |
Terminated |
NCT03214809 -
The Use of a Point-of-care Thoracic Ultrasound Protocol for Hospital Medical Emergency Teams
|
N/A | |
Not yet recruiting |
NCT03671070 -
Role of Low Dose Epinephrine Boluses In Acute Hypotension
|
N/A | |
Completed |
NCT04497155 -
Prehospital Norepinephrine and Early Mortality in Traumatic Shock
|
||
Completed |
NCT04269382 -
Accuracy of Non-Invasive Blood Pressure Measurements at the Arm, Calf , and Finger
|
N/A | |
Recruiting |
NCT05931601 -
Early Initiated Vasopressor Therapy in the Emergency Department
|
Phase 3 | |
Recruiting |
NCT05355974 -
Using Vasopressor Medication to Support Blood Pressure During Intubation Procedure
|
Phase 3 | |
Completed |
NCT04529005 -
Angiotensin II in the Perioperative Management of Hypotension in Kidney Transplant Recipients
|
Phase 4 |