Sonographic Assessment of the Effects of Mechanical Ventilation on Carotid Flow Time and Volume

The Four Truths 1. The truth of confusion 2. The truth of the origin of confusion 3. The truth of the cessation of confusion 4. The truth of the path leading to the cessation of confusion The 10-Fold Path 1. A breath is one cycle of positive flow (inspiration) and negative flow (expiration) defined in terms of the flow-time curve. 2. A breath is assisted if the ventilator does work on the patient. 3. A ventilator assists breathing using either pressure control or volume control based on the equation of motion for the respiratory system. 4. Breaths are classified by the criteria that trigger (start) and cycle (stop) inspiration 5. Trigger and cycle events can be initiated by the patient or the machine. 6. Breaths are classified as spontaneous or mandatory based on both the trigger and cycle events. 7. There are 3 breath sequences: Continuous mandatory ventilation (CMV), Intermittent Mandatory Ventilation (IMV), and Continuous Spontaneous Ventilation (CSV). 8. There are 5 basic ventilatory patterns: VC-CMV, VC-IMV, PC-CMV, PC-IMV, and PC-CSV: 9. Within each ventilatory pattern there are several variations that can be distinguished by their targeting scheme(s). 10. A mode of ventilation is classified according to its control variable, breath sequence, and targeting scheme(s). Keywords: Breath. Trigger, Cycle, Breath sequences, Ventilatory patterns, Mode of ventilation

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Comparing Changes in Carotid Flow Time and Stroke Volume Induced by Passive Leg Raising

The American Journal of the Medical Sciences ◽

10.1016/j.amjms.2017.09.006 ◽

2018 ◽

Vol 355 (2) ◽

pp. 168-173 ◽

Cited By ~ 9

Author(s):

Bilal Jalil ◽

Patton Thompson ◽

Rodrigo Cavallazzi ◽

Paul Marik ◽

Jason Mann ◽

...

Keyword(s):

Stroke Volume ◽

Flow Time ◽

Passive Leg Raising ◽

Carotid Flow

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Changes in corrected carotid flow time induced by recruitment maneuver predict fluid responsiveness in patients undergoing general anesthesia

Journal of Clinical Monitoring and Computing ◽

10.1007/s10877-021-00736-7 ◽

2021 ◽

Author(s):

Aya Kimura ◽

Koichi Suehiro ◽

Takashi Juri ◽

Katsuaki Tanaka ◽

Takashi Mori

Keyword(s):

General Anesthesia ◽

Fluid Responsiveness ◽

Recruitment Maneuver ◽

Flow Time ◽

Predict Fluid Responsiveness ◽

Carotid Flow

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Ability of Carotid Corrected Flow Time to Predict Fluid Responsiveness in Patients Mechanically Ventilated Using Low Tidal Volume after Surgery

Journal of Clinical Medicine ◽

10.3390/jcm10122676 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2676

Author(s):

Seungho Jung ◽

Jeongmin Kim ◽

Sungwon Na ◽

Won Seok Nam ◽

Do-Hyeong Kim

Keyword(s):

Mechanical Ventilation ◽

Tidal Volume ◽

Fluid Responsiveness ◽

Flow Time ◽

Volume Index ◽

Predict Fluid Responsiveness ◽

Low Tidal Volume ◽

Lower Accuracy ◽

Corrected Flow Time ◽

Corrected Flow

Predicting fluid responsiveness in patients under mechanical ventilation with low tidal volume (VT) is challenging. This study evaluated the ability of carotid corrected flow time (FTc) assessed by ultrasound for predicting the fluid responsiveness during low VT ventilation. Patients under postoperative mechanical ventilation and clinically diagnosed with hypovolemia were enrolled. Carotid FTc and pulse pressure variation (PPV) were measured at VT of 6 and 10 mL/kg predicted body weight (PBW). FTc was calculated using both Bazett’s (FTcB) and Wodey’s (FTcW) formulas. Fluid responsiveness was defined as a ≥15% increase in the stroke volume index assessed by FloTrac/Vigileo monitor after administration of 8 mL/kg of balanced crystalloid. Among 36 patients, 16 (44.4%) were fluid responders. The areas under the receiver operating characteristic curves (AUROCs) for the FTcB at VT of 6 and 10 mL/kg PBW were 0.897 (95% confidence interval [95% CI]: 0.750–0.973) and 0.895 (95% CI: 0.748–0.972), respectively. The AUROCs for the FTcW at VT of 6 and 10 mL/kg PBW were 0.875 (95% CI: 0.722–0.961) and 0.891 (95% CI: 0.744–0.970), respectively. However, PPV at VT of 6 mL/kg PBW (AUROC: 0.714, 95% CI: 0.539–0.852) showed significantly lower accuracy than that of PPV at VT of 10 mL/kg PBW (AUROC: 0.867, 95% CI: 0.712–0.957; p = 0.034). Carotid FTc can predict fluid responsiveness better than PPV during low VT ventilation. However, further studies using automated continuous monitoring system are needed before its clinical use.

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