Dataset Information

Noninvasive cardiac output monitoring in a porcine model using the inspired sinewave technique: a proof-of-concept study.

ABSTRACT:

Background

Cardiac output (Q˙) monitoring can support the management of high-risk surgical patients, but the pulmonary artery catheterisation required by the current 'gold standard'-bolus thermodilution (Q˙_T)-has the potential to cause life-threatening complications. We present a novel noninvasive and fully automated method that uses the inspired sinewave technique to continuously monitor cardiac output (Q˙_IST).

Methods

Over successive breaths the inspired nitrous oxide (N₂O) concentration was forced to oscillate sinusoidally with a fixed mean (4%), amplitude (3%), and period (60 s). Q˙_IST was determined in a single-compartment tidal ventilation lung model that used the resulting amplitude/phase of the expired N₂O sinewave. The agreement and trending ability of Q˙_IST were compared with Q˙_T during pharmacologically induced haemodynamic changes, before and after repeated lung lavages, in eight anaesthetised pigs.

Results

Before lung lavage, changes in Q˙_IST and Q˙_T from baseline had a mean bias of -0.52 L min^-1 (95% confidence interval [CI], -0.41 to -0.63). The concordance between Q˙_IST and Q˙_T was 92.5% as assessed by four-quadrant analysis, and polar plot analysis revealed a mean angular bias of 5.98° (95% CI, -24.4°-36.3°). After lung lavage, concordance was slightly reduced (89.4%), and the mean angular bias widened to 21.8° (-4.2°, 47.6°). Impaired trending ability correlated with shunt fraction (r=0.79, P<0.05).

Conclusions

The inspired sinewave technique provides continuous and noninvasive monitoring of cardiac output, with a 'marginal-good' trending ability compared with cardiac output based on thermodilution. However, the trending ability can be reduced with increasing shunt fraction, such as in acute lung injury.

SUBMITTER: Bruce RM

PROVIDER: S-EPMC6676057 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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Publications

Noninvasive cardiac output monitoring in a porcine model using the inspired sinewave technique: a proof-of-concept study.

Bruce Richard M RM Crockett Douglas C DC Morgan Anna A Tran Minh Cong MC Formenti Federico F Phan Phi Anh PA Farmery Andrew D AD

British journal of anaesthesia 20190404 2

<h4>Background</h4>Cardiac output (Q˙) monitoring can support the management of high-risk surgical patients, but the pulmonary artery catheterisation required by the current 'gold standard'-bolus thermodilution (Q˙<sub>T</sub>)-has the potential to cause life-threatening complications. We present a novel noninvasive and fully automated method that uses the inspired sinewave technique to continuously monitor cardiac output (Q˙<sub>IST</sub>).<h4>Methods</h4>Over successive breaths the inspired ni ...[more]

PMID: 30954237

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Project description:Background: Damaged cardiac tissues could potentially be regenerated by transplanting bioengineered cardiac patches to the heart surface. To be fully paradigm-shifting, such patches may need to be transplanted using minimally invasive robotic cardiac surgery (not only traditional open surgery). Here, we present novel robotic designs, initial prototyping and a new surgical operation for instruments to transplant patches via robotic minimally invasive heart surgery. Methods: Robotic surgical instruments and automated control systems were designed, tested with simulation software and prototyped. Surgical proof-of-concept testing was performed on a pig cadaver. Results: Three robotic instrument designs were developed. The first (called "Claw" for the claw-like patch holder at the tip) operates on a rack and pinion mechanism. The second design ("Shell-Beak") uses adjustable folding plates and rods with a bevel gear mechanism. The third ("HeartStamp") utilizes a stamp platform protruding through an adjustable ring. For the HeartStamp, rods run through a cylindrical structure designed to fit a uniportal Video-Assisted Thorascopic Surgery (VATS) surgical port. Designed to work with or without a sterile sheath, the patch is pushed out by the stamp platform as it protrudes. Two instrument robotic control systems were designed, simulated in silico and one of these underwent early 'sizing and learning' prototyping as a proof-of-concept. To reflect real surgical conditions, surgery was run "live" and reported exactly (as-it-happened). We successfully picked up, transferred and released a patch onto the heart using the HeartStamp in a pig cadaver model. Conclusion: These world-first designs, early prototypes and a novel surgical operation pave the way for robotic instruments for automated keyhole patch transplantation to the heart. Our novel approach is presented for others to build upon free from restrictions or cost-potentially a significant moment in myocardial regeneration surgery which may open a therapeutic avenue for patients unfit for traditional open surgery.

Dataset Information

Noninvasive cardiac output monitoring in a porcine model using the inspired sinewave technique: a proof-of-concept study.

Background

Methods

Results

Conclusions

Publications

Noninvasive cardiac output monitoring in a porcine model using the inspired sinewave technique: a proof-of-concept study.

Similar Datasets

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