Autonomic Challenges From Mild Hypovolemia and Mechanical Ventilation

Hypovolemia Clinical Trial

Official title:

Effects of Low Central Volume and Intermittent Positive Pressure Ventilation on the Heart Rate Variability

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03244891
• Other study ID #: HRV2017_Healthy
• Status: Completed
• Phase: N/A
• Start date: June 15, 2019
• Est. completion date: July 30, 2019

Study information

• Verified date: October 2019
• Source: ASST Fatebenefratelli Sacco
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Description:

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 12
• Est. completion date: July 30, 2019
• Est. primary completion date: July 30, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 35 Years

Eligibility

Inclusion Criteria:

• healthy volunteers

Exclusion Criteria:

• history of cardiac, metabolic, respiratory, renal, neurological or hematologic disease of any kind

• chronically assuming drugs of any kind

• non sinus cardiac rhythm

• ectopic beats >5% of all cardiac beats

• claustrophobia or unable to tolerate noninvasive ventilation via facial mask

Related Conditions & MeSH terms

• Autonomic Nervous System Imbalance
• Hypovolemia
• Positive-Pressure Respiration

Intervention

Other:
• Increase of central volume
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: baseline after fluid shift induced by passive head down position at 15 degrees after fluid challenge with Ringer acetate 15ml*kg in head down position A total of six steps will be considered for the analysis
• Ventilation mode
Each previous step will be done in two respiratory conditions: spontaneous breathing noninvasive ventilation via facial mask in pressure support mode at 8 cmH2O above positive end expiratory pressure of 5 cmH2O, inspiratory fraction of oxygen of 0.25 In both conditions respiratory rate will be set at 18 breaths per min following a metronome

Locations

Country	Name	City	State
Italy	ASST Fatebenefratelli Sacco, Luigi Sacco Hospital	Milan

Sponsors (1)

Lead Sponsor	Collaborator
ASST Fatebenefratelli Sacco

Country where clinical trial is conducted

Italy, 

References & Publications (6)

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. — View Citation

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. — View Citation

Galletly DC, Larsen PD. Relationship between cardioventilatory coupling and respiratory sinus arrhythmia. Br J Anaesth. 1998 Feb;80(2):164-8. — View Citation

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

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. — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Effects of increasing central blood volume on heart rate variability	The studied subjects will undergo to increase of central blood volume in two steps: passive head down tilt at -7 degrees; intravenous infusion of ringer acetate of 15ml*kg body weight	10 mins each step
Primary	Effect of cyclic intrathoracic pressure oscillations on heart rate variability	The studied subject will undergo to two ventilatory modes: spontaneous breathing at 18 breaths per min; positive pressure ventilation via face mask	10 min each step
Secondary	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