Monitoring and regulation of supported breathing in Intensive Care

This thesis describes several chapters related to monitoring and regulation of breathing. The main goal is to provide better insight in the interaction between spontaneous breathing and mechanical ventilatory support. In chapter 2 we investigated the effect of metabolic alkalosis on the ventilatory response. To analyze whether speckle tracking ultrasound can be used to noninvasively quantify diaphragm contractility, in chapter 3 this technique is used in healthy subjects undergoing a randomized stepwise threshold loading protocol. Chapters 4, 5 and 6 of this thesis focus on the interaction between the two parallel systems involved in providing adequate ventilation: the patient and more specific its upper airway, and the ventilator. We studied this interaction in patients with an acute exacerbation of COPD during noninvasive ventilation

ReSurfEMG

Commits <ul> <li>00b83ff: cleaning cff (C. Moore)</li> </ul>If you use this software please cite as belo

Influence of bicarbonate on ventilatory drive in healthy subjects

Background Acute hypoventilation results in CO2 retention and respiratory acidosis. Bicarbonate retention aims to restore pH level. However, after institution of mechanical ventilation metabolic alkalosis may develop, which could impair respiratory drive. Aim To investigate whether increased plasma bicarbonate reduces ventilatory drive and minute ventilation. Methods We enrolled 11 healthy volunteers. At baseline (t0), arterial blood gas (ABG) analysis and a hypercapnic ventilatory response (HCVR) test were performed while flow, diaphragm electrical activity (EAdi), and partial pressure of in- and expiratory CO2 were measured. 100 ml 8.4% sodium bicarbonate was administered for 10 times with 8 h interval. Subsequently, measurements were repeated (t1). Ratio between difference in start and end of minute ventilation (VE) and end-tidal CO2 pressure (PetCO2) was calculated. Results Bicarbonate levels increased from 25.2±2.2 mmol/L to 29.2±1.9 mmol/L. There was no difference in ΔVE/ΔPetCO2 between t0 (6.1±2.5 L·min-1/kPa) and t1 (6.3±2.6 L·min-1/kPa, p=0.76). Figure 1 shows mean EAdi and VE for each step of increasing inspiratory CO2. Akaike index on intra-individual fits showed a significant effect of bicarbonate on EAdi and a small effect on VE. Conclusion Increasing arterial bicarbonate reduces ventilatory drive in healthy subjects. The clinical importance is that it could be helpful to reduce plasma bicarbonate in selected difficult to wean patients

ReSurfEMG

Commits <ul> <li>f78257e: update changelog (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/244">#244</a></li> <li>2ec1449: update changelog (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/244">#244</a></li> <li>45a91d0: up to python 3.9 everywhere (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/245">#245</a></li> <li>ffabaaf: change docker to 3.9 on file (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/245">#245</a></li> <li>ccea0f1: fast update instructions (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/246">#246</a></li> <li>15df43d: Upgrade environment.yml to Python 3.9 (wvxvw) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/246">#246</a></li> <li>5275c14: checking array and other factors in new mne (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/246">#246</a></li> <li>ac1b797: update changelog and new-old environment file (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/246">#246</a></li> <li>5f2e444: paper changed as JOSS reviewers suggested (ElineOppersma) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/247">#247</a></li> <li>fdac9fb: fixing for next version to be 39 (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/248">#248</a></li> <li>7a99f73: add readme details (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/248">#248</a></li> <li>9f0742c: correct path for venv activation (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/249">#249</a></li> <li>a09cb40: fix mamba hyperlink, cosmetic (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/249">#249</a></li> <li>267389a: simplified (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/249">#249</a></li> <li>ccc59de: update readme for clarity (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/249">#249</a></li> <li>3afb6c0: start multiplatform install instructions (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>2bd289a: add etc folder and more test (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>8de17a0: redo internal link (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>aa24447: try hyphen for getting-started (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>0387c41: nonconda (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>7274f8f: try manual (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>703503c: final getting started link try (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>547b27a: Instructions for installing using pip / on Linux (wvxvw) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>a0d0d10: perfection (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>bc500ad: Walter corrections (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/253">#253</a></li> <li>57e5fe3: using double quotation in json (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>42ce952: notebook for getting started (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>7231ac5: removing config from cli (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>36aaf8d: usig synthetic data and multiple extensions (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>3606c77: added synthetic emg data (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>2740958: added testing and new notebook to readme file (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>7059cd3: Revert "removing config from cli" (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>e667a85: use config if paths are empty (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>55a7ebc: update environment with tkinter (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>eea0099: fixed extension search and use of path.join (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>41723a7: more elegant solution (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/250">#250</a></li> <li>6aafb46: update changelog (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/254">#254</a></li> <li>e471b96: get rid off egg (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/254">#254</a></li> <li>f850c37: reupdate change log to v0.1.1 (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/256">#256</a></li> <li>6ef7174: oleg suggestions (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/257">#257</a></li> <li>24ebebc: fix changelog (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/257">#257</a></li> <li>73d3619: release 0.1.2 (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/258">#258</a></li> <li>bceff91: changed getting ready notebook (Walter Baccinelli) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/259">#259</a></li> <li>013d8ec: retool developer instrucitons (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/260">#260</a></li> <li>f769645: [cr] Reworded paragraph about developers roles (wvxvw) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/260">#260</a></li> <li>12061b0: clarify install_dev further (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/260">#260</a></li> <li>36876d6: reword O (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/260">#260</a></li> <li>69c8d6d: bib update (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/265">#265</a></li> <li>91d025f: bib update (Candace Makeda Moore, MD) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/265">#265</a></li> <li>8f2e525: Suggested types/fix-ups for JOSS paper (AJQuinn) <a href="https://github.com/ReSurfEMG/ReSurfEMG/pull/266">#266</a></li> <li>4de4081: [fix] Conda no longer tolerates single equals in package version format (wvxvw)</li> </ul>If you use this software please cite as belo

MULTIBAR: Stata module to produce bar and dot graphs for use with overlapping over() categories

multibar creates bar and dot graph for overlapping over() categories. multibar is a wrapper for Stata's graph bar and graph dot. When entered correctly, multibar treats overlapping catgories as if they are not overlapping and, therefore, allows use of over().graph, bar graph, dot plot, overlapping categories

Functional assessment of the diaphragm by speckle tracking ultrasound during inspiratory loading

Assessment of diaphragmatic effort is challenging, especially in critically ill patients in the phase of weaning. Fractional thickening during inspiration assessed by ultrasound has been used to estimate diaphragm effort. It is unknown whether more sophisticated ultrasound techniques such as speckle tracking are superior in the quantification of inspiratory effort. This study evaluates the validity of speckle tracking ultrasound to quantify diaphragm contractility. Thirteen healthy volunteers underwent a randomized stepwise threshold loading protocol of 0-50% of the maximal inspiratory pressure. Electric activity of the diaphragm and transdiaphragmatic pressures were recorded. Speckle tracking ultrasound was used to assess strain and strain rate as measures of diaphragm tissue deformation and deformation velocity, respectively. Fractional thickening was assessed by measurement of diaphragm thickness at end-inspiration and endexpiration. Strain and strain rate increased with progressive loading of the diaphragm. Both strain and strain rate were highly correlated to transdiaphragmatic pressure (strain r2 = 0.72; strain rate r2 = 0.80) and diaphragm electric activity (strain r2 = 0.60; strain rate r2 = 0.66). We conclude that speckle tracking ultrasound is superior to conventional ultrasound techniques to estimate diaphragm contractility under inspiratory threshold loading. NEW & NOTEWORTHY Transdiaphragmatic pressure using esophageal and gastric balloons is the gold standard to assess diaphragm effort. However, this technique is invasive and requires expertise, and the interpretation may be complex. We report that speckle tracking ultrasound can be used to detect stepwise increases in diaphragmatic effort. Strain and strain rate were highly correlated with transdiaphragmatic pressure, and therefore, diaphragm electric activity and speckle tracking might serve as reliable tools to quantify diaphragm effort in the future