Unusual Capnography due to Incorrect Assembly of Spring with Absorber Valve into Breathing Circuit - Experience of Normocarbia: A Case Report / 대한구급학회지

A focus on patient safety has heightened the awareness of pateint mornitoring. The importantce of clinical application of capnography continues to grow, as reflected by the increasing number of medical societies recommending its use. We recently encountered an abnormal capnography undergoing gastrectomy. It was noted that the waveform was not sustained zero-baseline formation as seen during inspiratory phase, immediately upsloping for expiratory plateau followed by inspiratoy downsloping as like a shape of curare cleft. But PaCO2 was within normal range. We found that the source of the problem was the incorrect (bottom up) assembly of spring with absorber valve into the CUBE, the circle breathing system of Dameca Ventilator. Spring with absorber valve divides CUBE circle into inspiratory and expiratory space. We concluded that the unusual capnography was resulted from the incorrect assembly of it, subsequently mixing of inspiratory and exhaled gases and rebreathing was occurred with the block of a gas flow to CO2 canister. After correcting assembly, the capnography was normalized.

Vascular Response of Isolated Rat Thoracic Aorta after Chemical Hypoxia/Reoxygenation / 대한마취과학회지

BACKGROUND: Hypoxia/reoxygenation (H/R) results in formation of toxic reactive oxygen species (ROS), which can impair the vascular pathophysiology. Nitric oxide (NO) is an important free radical in many physiological or pathological processes including H/R injury. The loss of NO after H/R might be one of the major causes of an impaired vascular response. METHODS: Isolated rat aortic rings were prepared and NaCN was used to induce chemical hypoxia. The NaCN concentration and the hypoxia/reoxygenation time were determined by the responsiveness of phenylephrine (Phe), sodium nitroprusside (SNP) and acetylcholine (Ach). A cumulative doses of Phe and SNP (10(-9)-10(-5.5) M) were added to construct the vascular contraction and relaxation curves. The cumulative doses of Ach (10(-9)-10(-5) M) were added to construct the relaxation after precontraction with Phe (10(-6) M). The effects of the N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) and the superoxide dismutase (SOD, 50 unit) pretreatment during chemical H/R were evaluated. RESULTS: The NaCN concentration and H/R time were 1 mM, 30 minutes/5 minutes, respectively. Chemical hypoxia reduced the Phe-induced vascular contraction significantly. However chemical H/R increased the Phe-induced contraction significantly, and impaired the relaxation by SNP and Ach. A pretreatment with L-NAME increased the Phe-induced contraction and impaired the relaxation by SNP as well as Ach. The SOD pretreatment reduced the Phe-induced increased vascular contraction after NaCN-induced chemical H/R. CONCLUSIONS: NO plays a key role in endothelial-dependent relaxation and the recovery of the augmented contractility by vasoconstrictors after chemically-induced H/R.