Effect of Thiamine on Oxygen Utilization (VO2) in Critical Illness

Acute Respiratory Failure Clinical Trial

— VO2  

Official title:

The Effect of Thiamine on VO2 Levels in Critically Ill Patients

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01462279
• Other study ID #: 2010P000312
• Status: Completed
• Phase: N/A
• First received: October 25, 2011
• Last updated: December 11, 2017
• Start date: September 2011
• Est. completion date: October 2012

Study information

• Verified date: December 2017
• Source: Beth Israel Deaconess Medical Center
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The objective of this study is to determine the effect of thiamine therapy on oxygen consumption in critically-ill patients. The investigators will evaluate this by measuring VO2 before and after thiamine administration in patients admitted to the ICU and requiring mechanical ventilation.

Description:

Extensive research has been done over the past two decades looking at the role of oxygen delivery (DO2) and oxygen utilization (VO2) in critical illness. VO2 depends on cardiac output, arterial oxygen content, and the body's ability to extract oxygen effectively from the blood. Oxygen demand rises in critical illness as the body goes into a catabolic state, and lower VO2 has been associated with higher lactate levels and with poorer outcomes. Although increasing DO2 will often raise VO2, Hayes et al found that a subset of critically-ill patients failed to demonstrate a rise in VO2 in spite of achieving supranormal values of cardiac index (CI) and DO2. This group, in contrast to patients whose VO2 rose with the increase in CI and DO2, had exceedingly poor outcomes, suggesting that an inability to extract oxygen from the blood confers a poorer prognosis.(1)

Thiamine deficiency can manifest in several ways, but the syndrome of wet beriberi, caused by thiamine deficiency, includes lactic acidosis, cardiac decompensation and vasodilatory shock, similar to sepsis and other forms of critical illness. The mechanism by which thiamine deficiency causes dysfunction rests upon the vitamin's essential role in the Krebs cycle and Pentose Phosphate Pathway. Lack of adequate thiamine results in the failure of pyruvate to enter the Krebs Cycle, thus preventing aerobic metabolism. The resulting decrease in aerobic metabolism and increase in anaerobic metabolism leads to decreased oxygen consumption by the tissues and increased lactic acid production. The investigators group has found previously that upwards of 20% of critically ill patients with sepsis are thiamine deficient within 72 hours of presentation. In a dog model of septic shock, Lindenbaum et al have shown that, regardless of thiamine levels, supplementation with thiamine improved not only lactate clearance and mean arterial pressure, but increased VO2 as well. The effect of thiamine on VO2 in critically ill humans has not yet been reported, but an increase in VO2 max after administration of thiamine to healthy volunteers has been described. VO2 is known to rise in inflammatory states, reflecting increased energy expenditure. Prior studies have shown that VO2 will decrease with interventions such as fever control. In spite of VO2 being higher than normal in critically-ill patients, however, the end-organ damage and lactic acidosis suggest that it is not high enough to meet the metabolic demands of the critically-ill body. If the investigators were able to increase VO2 further in critically-ill patients, the investigators could potentially help maintain aerobic metabolism and decrease tissue hypoxia and the resulting end-organ damage. The investigators hypothesis is that administering thiamine intravenously to critically-ill patients will increase VO2.

Multiple methods of measuring VO2 have been used in the ICU, but in the current era where invasive monitoring with routine use of PA catheters is no longer the norm, indirect calorimetry became, for a time, the gold standard for measurement of gas exchange in critically ill, mechanically ventilated patients.(2) The metabolic cart used for indirect calorimetry is cumbersome and requires frequent calibration to maintain accuracy, however, and a newer, more portable method has been designed. The Datex-Ohmeda M-COVX device has been approved for the measurement of VO2 and VCO2 in mechanically ventilated patients. In studies, it has been validated as a method that is as accurate as indirect calorimetry, and perhaps even more accurate at higher FiO2.(3,4) The Datex-Ohmeda M-COVX connects to the Carescape B650 monitor made by GE, and measures VO2 through a single-use spirometer that attaches to the patient's ventilator tubing. In the following proposal, the investigators present a plan to examine the effect of thiamine therapy on VO2 in 30 critically-ill, mechanically ventilated patients, using the Datex-Ohmeda M-COVX module to measure VO2 before and after thiamine administration.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 20
• Est. completion date: October 2012
• Est. primary completion date: October 2012
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Adult patients (age > 18 years) admitted to an ICU

• Mechanically ventilated

Exclusion Criteria:

• Unstable ventilator settings during measurement of VO2

• Temp > 100 at time of VO2 measurement

• FIO2 > 60%

• Endotracheal cuff leak, chest tube, or other evident source of air leak

• Thiamine supplementation within 24 hours prior to study enrollment

Related Conditions & MeSH terms

• Acute Respiratory Failure
• Respiratory Distress Syndrome, Adult
• Respiratory Insufficiency

Intervention

Drug:
• Thiamine
200mg of intravenous thiamine in 50ml of D5W will be infused over 30 minutes once

Locations

Country	Name	City	State
United States	Beth Israel Deaconess Medical Center (BIDMC)	Boston	Massachusetts

Sponsors (2)

Lead Sponsor	Collaborator
Beth Israel Deaconess Medical Center	American Medical Association

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Improvement in VO2	VO2 measurements are taken at baseline and VO2 is continuously monitored over 9 hours. Thiamine is administered three hours after baseline measurements are taken.	Baseline to 9 Hours
Secondary	Improvement in Hemodynamics	Hemodynamics were collected in all patients but we did not evaluate change in hemodynamics over the 9 hour protocol of the study. Due to the single-arm nature and small size of the study, and with no comparison arm, we did not think we had the statistical power to evaluate for a change in hemodynamics so this was not a planned outcome and was entered in error.	Baseline to Nine Hours