Ignite Creation Date:
2024-05-06 @ 2:58 AM
Last Modification Date:
2024-10-26 @ 11:26 AM
Study NCT ID:
NCT02177188
Status:
COMPLETED
Last Update Posted:
2014-06-27
First Post:
2013-03-01
Brief Title:
HEAVy HAT-HEAlthy Volunteers Heart to Arm Time Haemorrhage Simulation Protocol in Healthy Volunteers
Sponsor:
University of Milano Bicocca
Organization:
University of Milano Bicocca
Study Overview
Official Title:
HEAVy HAT-HEAlthy Volunteers Heart to Arm Time Haemorrhage Simulation Protocol in Healthy Volunteers
Status:
COMPLETED
Status Verified Date:
2014-06
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
HEAvyHAT
Brief Summary:
In prehospital settings hypovolemic shock diagnosis is based on Advanced Trauma Life Support ATLS shock classification The most often used clinical signs are heart rate HR arterial blood pressure BP respiratory rate neurologic status diuresis skin colour and temperature However some of these signs such as hypotension and tachycardia lack specificity and sensitivity and do not occur early enough Even with an early preload reduction blood pressure can remain constant due to compensatory mechanisms such as vasoconstriction and positive chronotropism Tachycardia occurs earlier but has poor specificity and sensitivity A retrospective analysis of 25287 trauma patients showed that among 489 patients presenting with systolic BP 90 mmHg only 65 had tachycardia HR 90 bpm while 39 of patients with systolic BP 120 mmHg were tachycardic probably resulting from other stimuli influencing heart rate such as pain fear circulating hormones and endogenous enkephalins Therefore it could be very useful to have an index that identifies initial volume variation when physiological regulatory mechanisms are still effectively maintaining normal BP
Pulse transit time PTT is the sum of pre-ejection period PEP the time interval between the onset of ventricular depolarization and ventricular ejection and vascular transit time VTT the time it takes for the pulse wave to travel from the aortic valve to peripheral arteries PEP and VTT variations depend on preload variation and PTT increases with PEP showing a linear correlation R2 096 Chan et al subjected 11 healthy volunteers to the head-up tilt test and demonstrated that PEP increased and VTT decreased for increasing tilt angles from 0 to 80 corresponding to light-moderate bleeding They also observed early sympathetic activation expressed by decreases of both RR interval RR and VTT dampening the PTT increase since PTT is influenced by both continuous PEP increase and progressive VTT decrease occurring during hypovolaemia
Here the investigators describe a new index called indexed Heart to Arm Time iHAT iHAT is the mPTTRR ratio where mPTT is a modified PTT measured from the onset of ventricular depolarization the R wave of the ECG trace to the systolic peak of the photoplethysmographic pulse oxymetry PPG waveform mPTT is indexed to RR interval on ECG to counteract sympathetic activation that would dampen PEP increase and enhance VTT reduction by means of positive inotropism and peripheral vasoconstriction respectively iHAT therefore increases during haemorrhage because of preload reduction and the consequent PEP increase and RR interval decrease iHAT is expressed as the time percentage of the interbeat interval RR it takes to the PPG waveform to travel to peripheral arteries In this study iHAT has been calculated as the average of beat-to-beat mPTTRR ratios over 30 heart beats corresponding to at least 2 breathing cycles in order to minimize the effect of spontaneous breathing on preload and thus on PEP and PTT
In the present study the investigators aimed to evaluate iHAT in a simulating model of hypovolaemia by using a Lower Body Negative Pressure LBNP chamber LBNP chamber simulates haemorrhage by applying negative pressure to the lower limbs thus giving an accurate model of hypovolemia The LBNP chamber has been used for many years for research purposes and in 2001 Convertino suggested it is a useful device to test severe haemorrhage-related hemodynamic responses In fact the induced volemic sequestration is an efficient technique to study physiological behaviours in humans
The primary endpoint was to evaluate the use of the iHAT as a predictor of hypovolaemia The secondary endpoint was to compare the specificity and sensitivity of the iHAT index compared to commonly used indexes BP HR Furthermore the investigators aimed to assess feasibility of Transthoracic echocardiography TTE evaluation of Cardiac Output CO in a haemorrhagic model and to evaluate CO changes with respect to measured hemodynamic variables
TTE evaluation of CO is non invasive and comparable to thermodilution and of possible use in an emergency setting
Pulse transit time PTT is the sum of pre-ejection period PEP the time interval between the onset of ventricular depolarization and ventricular ejection and vascular transit time VTT the time it takes for the pulse wave to travel from the aortic valve to peripheral arteries PEP and VTT variations depend on preload variation and PTT increases with PEP showing a linear correlation R2 096 Chan et al subjected 11 healthy volunteers to the head-up tilt test and demonstrated that PEP increased and VTT decreased for increasing tilt angles from 0 to 80 corresponding to light-moderate bleeding They also observed early sympathetic activation expressed by decreases of both RR interval RR and VTT dampening the PTT increase since PTT is influenced by both continuous PEP increase and progressive VTT decrease occurring during hypovolaemia
Here the investigators describe a new index called indexed Heart to Arm Time iHAT iHAT is the mPTTRR ratio where mPTT is a modified PTT measured from the onset of ventricular depolarization the R wave of the ECG trace to the systolic peak of the photoplethysmographic pulse oxymetry PPG waveform mPTT is indexed to RR interval on ECG to counteract sympathetic activation that would dampen PEP increase and enhance VTT reduction by means of positive inotropism and peripheral vasoconstriction respectively iHAT therefore increases during haemorrhage because of preload reduction and the consequent PEP increase and RR interval decrease iHAT is expressed as the time percentage of the interbeat interval RR it takes to the PPG waveform to travel to peripheral arteries In this study iHAT has been calculated as the average of beat-to-beat mPTTRR ratios over 30 heart beats corresponding to at least 2 breathing cycles in order to minimize the effect of spontaneous breathing on preload and thus on PEP and PTT
In the present study the investigators aimed to evaluate iHAT in a simulating model of hypovolaemia by using a Lower Body Negative Pressure LBNP chamber LBNP chamber simulates haemorrhage by applying negative pressure to the lower limbs thus giving an accurate model of hypovolemia The LBNP chamber has been used for many years for research purposes and in 2001 Convertino suggested it is a useful device to test severe haemorrhage-related hemodynamic responses In fact the induced volemic sequestration is an efficient technique to study physiological behaviours in humans
The primary endpoint was to evaluate the use of the iHAT as a predictor of hypovolaemia The secondary endpoint was to compare the specificity and sensitivity of the iHAT index compared to commonly used indexes BP HR Furthermore the investigators aimed to assess feasibility of Transthoracic echocardiography TTE evaluation of Cardiac Output CO in a haemorrhagic model and to evaluate CO changes with respect to measured hemodynamic variables
TTE evaluation of CO is non invasive and comparable to thermodilution and of possible use in an emergency setting
Detailed Description:
None
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None