8th paper of my #adventarticles: A great paper on why blindly normalising abnormal physiological values in isolation, rather than indentifying underlying pathology and treating that, is potentially dangerous and wrong. https://link.springer.com/article/10.1007/s00134-005-2729-7

7th paper of my #adventarticles: Must read paper (from @f2harrell, Darrel Francis among others) on prognostic thresholds, the danger of dichotomania. Optimum prognostic threshold is meaningless without describing the shape of the relationship between risk factor and risk, and most often serves just to seperate populations in two equal parts, not some real threshold where risk increases dramatically.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903471/ #statistics

6th paper of my #adventarticles: E/E’ has fair correlation to LAP under certain conditions across populations, but how does it track within individual change in LAP? Poorly it seems in this study, and several others have shown E/E’ increasing in healthy hearts with preload reduction. https://www.ahajournals.org/doi/full/10.1161/CIRCIMAGING.110.960575 #echocardiography #critcareecho #physiology

5th paper among my #adventarticles: One of the most beautiful and educational articles I’ve read in last few years, explains elegantly why lactate is not a specific perfusion marker, it’s not a specific marker of anaerobic metabolism. Rather, it’s a marker of glycolysis outpacing mithocondrial consumption even in the presence of plentiful oxygen , as the TCA cycle is much slower than glycolysis, though more more nutrient efficient. https://www.nature.com/articles/s41467-019-12934-8 #physiology

4th papers of my #adventarticles: This time not an original article, but the authors response to criticism. It’s the most succinct and convincing explanation of why single beat estimation of ventricular elastance is likely impossible, particularly in the critically ill/perioperative setting. https://www.bjanaesthesia.org/article/S0007-0912(17)31876-7/fulltext #cardiology #physiology #critcareecho

4th papers of my #adventarticles: This time not an original article, but the authors response to criticism. It’s the most succinct and convincing explanation of why single beat estimation of ventricular elastance is likely impossible, particularly in the critically ill/perioperative setting. https://www.bjanaesthesia.org.uk/article/S0007-0912(17)31876-7/pdf #cardiology #physiology #critcareecho

3rd paper of my #adventarticles: Still on the theme of V-A coupling, this paper attempting to validate multiple noninvasive measures of contractility, including Chen’s single beat method for estimating Emax, lead me down a rabbit hole and finding the lack of validity of single-beat measures for ventricular elastance. In this study, single-beat estimated Emax reflects afterload, not contractility. https://www.ahajournals.org/doi/full/10.1161/CIRCIMAGING.113.000722 #physiology #cardiology #critcareecho

2nd day of #adventarticles. Today I’m sharing a great primer on the ventriculoarterial coupling framework, particularly it’s strengths and limitations as a physiological model.

“All models are wrong, but some are useful” is as true for physiological as for statistical models. It is crucial to understand how they are wrong to make them useful.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3809068/

#physiology #criticalcare #cardiology

1st day of #adventarticles, sharing some of my all time favourite papers:
"Ejection Fraction Revisited" from Robotham et al, THE paper to read on ejection fraction.
One of many key takeaways:
Hyperdynamic LV/supranormal EF is not a sign of low preload, on the contrary EF is relatively preload insensitive and if anything very low preload lowers EF.
https://pubs.asahq.org/anesthesiology/article/74/1/172/31892/Ejection-Fraction-Revisited #physiology #criticalcare #echocardiography