Advertisement

Corrected flow time: a noninvasive ultrasound measure to detect preload reduction by nitroglycerin

      Abstract

      Objective

      Monitoring of patient's intravascular volume status without invasive measures remains challenging and unreliable. Our objective was to determine if corrected flow time (FTc) measurement could detect preload reduction with administration of nitroglycerin (NTG) as a surrogate for volume loss.

      Methods

      Post hoc FTc analysis was performed for a prospective cohort study of pulsed wave spectral Doppler measurements before and after administration of NTG. Patients enrolled were eligible for inclusion if they were admitted to a chest pain center for cardiac evaluation. Descriptive statistics, t tests, bivariate regression, and intraclass correlation coefficient were performed as appropriate.

      Results

      Fifty-four patients had Doppler measurements available for review. Mean FTc decreased from 339 milliseconds (95% confidence interval, 332-346) to 325 milliseconds (95% confidence interval, 318-331) with administration of 0.3 mg of sublingual NTG (P = .0001). Mean heart rate increased 5 beats/min with administration of NTG (P < .0001); however, there was no significant change in systolic or diastolic blood pressure.

      Conclusion

      Corrected flow time was able to detect a significant difference in preload reduction with 0.3 mg of NTG. The FTc may be an early reliable noninvasive measure to detect changes in intravascular volume status.
      To read this article in full you will need to make a payment
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to The American Journal of Emergency Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Gassner M
        • Killu K
        • Bauman Z
        • Coba V
        • Rosso K
        • Blyden D
        Feasibility of common carotid artery point of care ultrasound in cardiac output measurements compared to invasive methods.
        J Ultrasound. 2014; https://doi.org/10.1007/s40477-014-0139-9
        • Marik PE
        • Levitov A
        • Young A
        • Andrews L
        The use of bioreactance and carotid Doppler to determine volume responsiveness and blood flow redistribution following passive leg raising in hemodynamically unstable patients.
        Chest. 2013; 143: 364-370https://doi.org/10.1378/chest.12-1274
        • Blehar DJ
        • Glazier S
        • Gaspari RJ
        Correlation of corrected flow time in the carotid artery with changes in intravascular volume status.
        J Crit Care. 2014; 29: 486-488https://doi.org/10.1016/j.jcrc.2014.03.025
        • Safdar B
        • Ali A
        • D'Onofrio G
        • Katz SD
        Microvascular dysfunction as opposed to conduit artery disease explains sex-specific chest pain in emergency department patients with low to moderate cardiac risk.
        Clin Ther. 2016; https://doi.org/10.1016/j.clinthera.2015.12.010
        • Corretti MC
        • Anderson TJ
        • Benjamin EJ
        • Celermajer D
        • Charbonneau F
        • Creager MA
        • et al.
        Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery: a report of the International Brachial Artery Reactivity Task Force.
        J Am Coll Cardiol. 2002; 39: 257-265https://doi.org/10.1016/S0735-1097(01)01746-6
        • Haber HL
        • Simek CL
        • Bergin JD
        • Sadun A
        • Gimple LW
        • Powers ER
        • et al.
        Bolus intravenous nitroglycerin predominantly reduces afterload in patients with excessive arterial elastance.
        J Am Coll Cardiol. 1993; 22: 251-257
        • Mackenzie DC
        • Khan NA
        • Blehar D
        • Glazier S
        • Chang Y
        • Stowell CP
        • et al.
        Carotid flow time changes with volume status in acute blood loss.
        Ann Emerg Med. 2015; https://doi.org/10.1016/j.annemergmed.2015.04.014
        • Verheyden B
        • Gisolf J
        • Beckers F
        • Karemaker JM
        • Wesseling KH
        • Aubert AE
        • et al.
        Impact of age on the vasovagal response provoked by sublingual nitroglycerine in routine tilt testing.
        Clin Sci (Lond). 2007; 113: 329-337https://doi.org/10.1042/CS20070042
        • Lanza GA
        • Spera FR
        • Villano A
        • Russo G
        • Di Franco A
        • Lamendola P
        • et al.
        Effect of smoking on endothelium-independent vasodilatation.
        Atherosclerosis. 2015; 240: 330-332https://doi.org/10.1016/j.atherosclerosis.2015.03.041
        • Kawano N
        • Emoto M
        • Mori K
        • Yamazaki Y
        • Urata H
        • Tsuchikura S
        • et al.
        Association of endothelial and vascular smooth muscle dysfunction with cardiovascular risk factors, vascular complications, and subclinical carotid atherosclerosis in type 2 diabetic patients.
        J Atheroscler Thromb. 2012; 19: 276-284
        • O'Rourke MF
        • Pauca A
        • Jiang X-J
        Pulse wave analysis.
        Br J Clin Pharmacol. 2001; 51: 507-522https://doi.org/10.1046/j.0306-5251.2001.01400.x