Effects of almitrine bismesylate on arterial blood gases in patients with chronic obstructive pulmonary disease and moderate hypoxaemia: a multicentre, randomised, double-blind, placebo-controlled study

The hypoxic pulmonary vasoconstriction: From physiology to clinical application in thoracic surgery

More than 70 years after its original report, the hypoxic pulmonary vasoconstriction (HPV) response continues to spark scientific interest on its mechanisms and clinical implications, particularly for anesthesiologists involved in thoracic surgery. Selective airway intubation and one-lung ventilation (OLV) facilitates the surgical intervention on a collapsed lung while the HPV redirects blood flow from the "upper" non-ventilated hypoxic lung to the "dependent" ventilated lung. Therefore, by limiting intrapulmonary shunting and optimizing ventilation-to-perfusion (V/Q) ratio, the fall in arterial oxygen pressure (PaO₂) is attenuated during OLV. The HPV involves a biphasic response mobilizing calcium within pulmonary vascular smooth muscles, which is activated within seconds after exposure to low alveolar oxygen pressure and that gradually disappears upon re-oxygenation. Many factors including acid-base balance, the degree of lung expansion, circulatory volemia as well as lung diseases and patient age affect HPV. Anesthetic agents, analgesics and cardiovascular medications may also interfer with HPV during the perioperative period. Since HPV represents the homeostatic mechanism for regional ventilation-to-perfusion matching and in turn, for optimal pulmonary oxygen uptake, a clear understanding of HPV is clinically relevant for all anesthesiologists.

The crystal structure of N-((3,5-di-tert-butyl-4-hydroxyphenyl)(phenyl)methyl)-4-methylbenzenesulfonamide, C28H35N3S

C28H35NO3S, triclinic, P1̄ (no. 2), a = 10.3965(4) Å, b = 10.7525(5) Å, c = 12.2772(6) Å, α = 86.651(4)°, β = 86.653(4)°, γ = 75.323(4)°, V = 1324.05(11) Å3, Z = 2, R gt(F) = 0.0472, wR ref(F 2) = 0.1298, T = 291 K.

Testing the usefulness of the number needed to treat to be harmed (NNTH) in benefit-risk evaluations: case study with medicines withdrawn from the European market due to safety reasons

OBJECTIVE

To explore the usefulness of number needed to treat to be harmed (NNTH), in benefit-risk assessments, by studying the agreement between NNTH values and withdrawals of medicines from European market due to safety reasons.

METHODS

Medicines with data from longitudinal studies were included. Studies were identified from European Medicines Agency's Reports. Meta-analyses were performed to pool odds ratios (OR) with 95% confidence-intervals (CI). Published control event rates were applied to ORs to calculate NNTHs (95%CI) for selected adverse events.

RESULTS

NNTH (95%CI) decreased from pre- to post-marketing for the eight medicines included: peripheral neuropathy (∞ vs. 12[non-significant; NS] with almitrine; heart valve disease with benfluorex (∞ vs. NNTH ranging from 7[4-13] to 7[5-9]); myopathy (-4096[NS] vs. 797[421-1690]), new-onset diabetes (113[NS] vs. 390[425-778]), bleeding (∞ vs. 517[317-1153]), and infection (∞ vs. 253[164-463]) with niacin-laropiprant; psychiatric disorders (12[7-34] vs. 9[5-24]) with rimonabant; myocardial infarction (MI) [-1305 vs. 270[89-4362]) with rofecoxib; MI (-510 vs. NNTH ranging from 152[55-4003] to 568[344-1350]) with rosiglitazone; cardiovascular events (∞ vs. 245[129-1318]) with sibutramine; and liver injury (∞ vs. 5957[NS]) with ximelagatran.

CONCLUSION

NNTH have potential of use as a supportive tool in benefit-risk re-evaluations of medicines and may help regulators to making decisions on drug safety.

Human pulmonary vascular responses to hypoxia and hypercapnia

The ability of alveolar gas composition to influence pulmonary vascular tone has been appreciated for over 50 years. In particular, it has been proposed that both O2 and CO2 could play a role in the matching of perfusion to ventilation within the lung, improving the overall efficiency of gas exchange. A wide variety of experimental approaches has been used to investigate pulmonary vascular effects of the respiratory gases in a range of mammalian species. In this article, we review experiments performed in healthy humans, identify particular difficulties in the interpretation of such experiments, and discuss possible approaches to future study.