Using the gli spirographic prediction equations to revisit the allometric relationships between lung volumes, height and age in adults

The determination the forced vital capacity (FVC) and the forced expiratory volume in 1 second (FEV1) during spirometry studies, is at the core of the evaluation of the pulmonary function of patients with respiratory diseases. The Global Lung Function Initiative (GLI) offers the most extensive data set of normal lung functions available, which is currently used to determine the average expected/predicted FEV1 and FVC (predV), and their lower limit of normal (LLN, 5th percentile) at any given height and age for women and men. These prediction equations are currently expressed in a rather complex form: predV = exp [p+ (a x Ln (height) + (n x Ln (age)) + spline] and LLN = exp(Ln (predV) + Ln (1 - 1.645 x S x CV)/S); and are currently used to generate interpretations in commercialized spinographic system. However, as shown in this paper, these equations contain physiological and fundamental allometric information on lung volumes that become obvious when rewriting mean predicted values as a "simple" power function of height and LLN as a percentage of the mean predicted values. We therefore propose to present the equations of prediction obtained from the GLI data using simplified expressions in adults (18-95 years old) to reveal some of their physiological and allometric meaning. Indeed, when predicted FEV1 and FVC (predV) were expressed under the form predV= αx heightax b(age), the resulting exponent (a) ranges between 2 and 3, transforming the one dimension of a length (size) into a volume, akin to the third-order power (cubic) function of height historically used to predict lung volumes. Only one function, b (age), is necessary to replace all the factors related to age, including the tables of discrete data of spline functions original equations. Similarly, LLN can be expressed as LLN = c (age) xpredV to become a simple percentage of the predicted values, as a function of age. The equations with their respective new polynomial functions were validated in 52,764 consecutive spirometry tests performed in 2022 in 22,612 men and 30,152 women at the Cleveland Clinic. Using these equations, it become obvious that for both women and men, FEV1/FVC ratio decreases with the size as the exponent of the power function of height is lower for FEV1 than FVC. We conclude that rewriting the GLI predicted equations with simpler formulations restitutes to the GLI data some of their original allometric meaning, without altering the accuracy of their prediction.

Improvement of pulmonary graft after storage for twenty-four hours by in vivo administration of lazaroid U74389G: functional and morphologic analysis

BACKGROUND

We examined the effects of in vivo administration of a potent inhibitor of iron-dependent lipid peroxidation, lazaroid U74389G, on lung preservation.

METHODS

Lungs isolated from Sprague-Dawley rats (n = 23) were either immediately reperfused after removal (control, n = 8) for 2 hours by means of an isolated, pulsatile blood perfusion system or reperfused after cold storage (4 degrees C) for 24 hours in the University of Wisconsin solution with (n = 7) or without (n = 8) lazaroid. The lazaroid group had in vivo infusion of lazaroid U74389G (6 mg/kg) before lung harvest plus addition to the perfusate (50 mu mol/L) at the onset of reperfusion. Routine aerodynamics, hemodynamics, and blood gases were assessed during the perfusion period. Lipid peroxidation in the lung tissue was assayed with the thiobarbituric acid-reactive product, malondialdehyde. Histologic evaluation was performed with light microscopic and transmission electron microscopic analyses.

RESULTS

All lungs in the University of Wisconsin solution group (24-hour storage without lazaroid) failed within 1 hour of reperfusion. Lungs in control and University of Wisconsin solution + lazaroid group survived the 2-hour perfusion period. University of Wisconsin solution + lazaroid group showed significantly better arterial oxygen tension values relative to those in the University of Wisconsin solution group (control, 85.2 +/- 1.9; University of Wisconsin solution, 53.9 +/- 3.2 [p < 0.05 versus control group and University of Wisconsin solution + lazaroid]; University of Wisconsin solution + lazaroid, 74.8 +/- 1.4; arterial oxygen tension (mm Hg) at 30 minutes). Lipid peroxide in University of Wisconsin solution + lazaroid group was significantly lower than that of the University of Wisconsin solution group (65.0 +/- 5.0 versus 495 +/- 105 nmol malondialdehyde/gm wet lung tissue; p < 0.01). Transmission electron microscopic analysis showed that University of Wisconsin solution + lazaroid group significantly attenuated lung damage when compared with University of Wisconsin solution group.

CONCLUSION

Administration of lazaroids in vivo before organ harvest and in situ at the onset of the reperfusion enhances lung preservation in this model.

Interdisciplinary treatment of morbidity in benign chest pain

This study tested the hypothesis that functional morbidity in benign chest pain can be modified independently of symptoms through interdisciplinary medical and cognitive-behavioral intervention. Analyses used data collected in a sixteen-week trial of interdisciplinary treatment for disability in benign chest pain. One hundred four chest pain patients having normal coronary arteriograms (NCA) (n = 14) or mitral valve prolapse (MVP) with no other known cardiac or arterial disease (n = 90) were assigned to individual treatment, group treatment, self-monitoring attention control, or a wait-list control group. Results indicate that interdisciplinary intervention, in group or individualized format, was successful for improving short-term and long-term (follow-up range = six to sixteen months) functional status, in both MVP and NCA patients. Correlation analysis indicated that functional improvements were not dependent on reductions in the frequency of symptoms. In fact, significant reductions in disability were obtained in those treated patients (13 of 43) who reported no reduction, or an actual increase, in the frequency of chest symptoms. These data indicate that disability in benign chest pain may be modified independently of symptoms by an integration of medical and cognitive-behavioral strategies.

Heroin "overdose" death: contribution of drug-associated environmental cues

A model of "overdose" deaths among heroin addicts is proposed which emphasizes recent findings concerning the contribution of drug-associated environmental cues to drug tolerance. Results of animal experiments performed to evaluate this model suggest that conditioned drug-anticipatory responses, in addition to pharmacological factors, affect heroin-induced mortality.