Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Heart Rate Variability (HRV) analysis has been studied in the critically ill patients although it is affected by several uncontrolled variables in the clinical conditions. The aim of this trial is to measure the effects of mildly reduced central volume and cyclic variation of intrathoracic pressure on the variables frequently used to describe the HRV.
Twelve healthy volunteers will be studied. Mild hypovolemia will be induced by 12 hours fasting from food and drinks. At 8.30 AM the study protocol will start. The studied subjects will lie calm supine in a ICU bed able to provide passive head up and head down tilt. They will be connected to a Siemens SC9000 monitor showing their ECG waves and to a Nexfin (BMEYE) monitor for continuous noninvasive blood pressure (NBP) assessment. Both waves (ECG and NBP) will be recorded on a laptop PC through analogic/digital input/output converter (PowerLab 8/35, ADinstruments). The studied subjects will undergo to a sequence of (1) spontaneous breathing at 10 degrees head up, (2) spontaneous breathing at 7 degrees head down, (3) noninvasive ventilation at 10 degrees head up, and (4) noninvasive ventilation at 7 degrees head down. The sequence 1-2-3-4 will be randomized. After this four phases, a fluid challenge of ringer acetate 15ml*kg will be intravenously administered and the a sequence 1-2-3-4 will be repeated after a new randomization. Noninvasive ventilation will be provided with a facial mask with ventilatory setting: Psupp 8 cmH2O, PEEP 5 cmH2O, FiO2 0.28. Psupp will be decreased by 2 cmH2O steps if the inspiratory tidal volume will be >10ml*kg. During both spontaneous breathing and noninvasive ventilation the subjects will breathe following a metronome at 18bpm.
HRV analysis will be conducted following the recommendation of the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (see reference).
Furthermore, the healthy volunteers will be studied by trans-thoracic ultrasound assessment with a Philips EPIQ7 sonographer, during each study phase.
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Studied subjects | Experimental | Each subject will be studied during two sequential phases:
During each phase, the subjects will be studied at:
|
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Increase of central volume | Other | Mild hypovolemia will be induced in healthy volunteers by 12 hours fasting. Three conditions will be considered for the analysis, each of them both during spontaneous breathing and positive pressure ventilation:
A total of six steps will be considered for the analysis |
| Measure | Description | Time Frame |
|---|---|---|
| Effects of increasing central blood volume on heart rate variability | The studied subjects will undergo to increase of central blood volume in two steps:
| 10 mins each step |
| Effect of cyclic intrathoracic pressure oscillations on heart rate variability | The studied subject will undergo to two ventilatory modes:
| 10 min each step |
| Measure | Description | Time Frame |
|---|---|---|
| Effects of increasing central blood volume and of cyclic intrathoracic pressure oscillations on echographic cardiac function variables | At each step cardiac functionality assessment will be done by transthoracic echocardiography | 10 mins each step |
Not provided
Inclusion Criteria:
Exclusion Criteria:
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| ASST Fatebenefratelli Sacco, Luigi Sacco Hospital | Milan | 20157 | Italy |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| Background | Guyton JE, Arthur C. The Autonomic Nervous System and The Adrenal Medulla, in Textbook of Medical Physiology, 12th ed., Saunders Elsevier, Ed. Philadelphia, 2011, pp. 738-739 | ||
| 6166045 | Background | Akselrod S, Gordon D, Ubel FA, Shannon DC, Berger AC, Cohen RJ. Power spectrum analysis of heart rate fluctuation: a quantitative probe of beat-to-beat cardiovascular control. Science. 1981 Jul 10;213(4504):220-2. doi: 10.1126/science.6166045. | |
| 25793464 |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| ID | Term |
|---|---|
| D020896 | Hypovolemia |
| ID | Term |
|---|---|
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
Not provided
Not provided
| ID | Term |
|---|---|
| D045422 | Continuous Positive Airway Pressure |
| ID | Term |
|---|---|
| D011175 | Positive-Pressure Respiration |
| D012121 | Respiration, Artificial |
| D058109 | Airway Management |
| D013812 | Therapeutics |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
|
| Ventilation mode | Other | Each previous step will be done in two respiratory conditions:
|
|
| Background |
| Ferrario M, Moissl U, Garzotto F, Cruz DN, Tetta C, Signorini MG, Ronco C, Grassmann A, Cerutti S, Guzzetti S. The forgotten role of central volume in low frequency oscillations of heart rate variability. PLoS One. 2015 Mar 20;10(3):e0120167. doi: 10.1371/journal.pone.0120167. eCollection 2015. |
| 9602579 | Background | Galletly DC, Larsen PD. Relationship between cardioventilatory coupling and respiratory sinus arrhythmia. Br J Anaesth. 1998 Feb;80(2):164-8. doi: 10.1093/bja/80.2.164. |
| 16540963 | Background | Monnet X, Rienzo M, Osman D, Anguel N, Richard C, Pinsky MR, Teboul JL. Passive leg raising predicts fluid responsiveness in the critically ill. Crit Care Med. 2006 May;34(5):1402-7. doi: 10.1097/01.CCM.0000215453.11735.06. |
| 8598068 | Background | Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation. 1996 Mar 1;93(5):1043-65. No abstract available. |
| D012138 |
| Respiratory Therapy |