Clearance of Mucus from Endotracheal Tubes during Intratracheal Pulmonary Ventilation

Background: Intratracheal pulmonary ventilation (ITPV) is a form of tracheal gas insufflation in which all gas emerges in a cephalad direction from the tip of a reverse-thrust catheter positioned within an endotracheal tube. In vitro experiments have shown that this rapid gas flow, with 5 ml/h of normal saline added to the gas flow, continuously removes tracheal secretions from within the endotracheal tube. The authors evaluated its effectiveness to remove mucus in long-term studies in sheep.

Methods: Fourteen healthy sheep were tracheally intubated and ventilated for 3 days with ITPV or with volume-controlled ventilation. Measurements were made of the total amount of secretions within the endotracheal tubes (weight gain), the protein content within the endotracheal tubes, and the increase in resistance to constant air flow. The structure of the airways was examined grossly and histologically. Three additional sheep were ventilated for 24 h with ITPV, and Evans Blue dye was added to the saline to assess the distribution of the infused saline.

Results: There was significantly less mucus in endotracheal tubes of sheep ventilated with ITPV than with conventional ventilation, as shown by minimal weight gain (0.70 +/- 0.14 g vs. 2.44 +/- 0.81 g; P < 0.001), lower protein content (14.09 +/- 10.79 mg vs. 294.99 +/- 153.06 mg; P <0.001), and lower resistance to constant air flow (6.15 +/- 0.54 cm H2 O [center dot] l sup -1 [center dot] s sup -1 vs. 15.34 +/- 5.28 cm H2 O [center dot] l sup -1 [center dot] s sup -1; P < 0.001). Results of gross and histological examinations of the tracheas of animals in both groups were similar, and the tracheas were well preserved. More than 95% of the instilled saline was recovered during ITPV. Only traces of Evans Blue dye were found near the tip of the endotracheal tubes.     

Current concepts of consciousness with some implications for anesthesia

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - The GW theory suggests that consciousness enables multiple networks to cooperate and compete in solving problems, such as...     

Karyotype abnormalities and their clinical significance in blast crisis of chronic myeloid leukemia

We examined karyotypes and their prognostic significance in a series of 122 patients with chronic myeloid leukemia in blast crisis. Of 73 patients cytogenetically examined at the onset of blast crisis 63% had developed secondary cytogenetic abnormalities in addition to the Philadelphia chromosome. These newly emerging abnormalities included a double Philadelphia chromosome in 20 patients, a trisomy 8 in 17, and an isochromosome 17q in 11 patients. Development of such additional karyotypic abnormalities was significantly associated with a shorter median survival and less response to cytoreductive treatment and was significantly more common in nonlymphoid blast crisis than in the lymphoid-type blast crisis. Thus, assessment of karyotypes at the onset of chronic myeloid leukemia blast crisis appears to be of prognostic significance for both remission duration and survival.     

Effect of melatonin and metabolites on copper-mediated oxidation of low density lipoprotein

Aims A prophylactic use of melatonin as an anti-ageing drug has recently gained public interest due to its radical scavenging property in vitro . The present study was designed to investigate a possible antiatherogenic effect of melatonin and its physiological metabolites by examining their action on the radical-initiated formation of oxidized LDL, which is known to possess a high atherogenic potency. The metabolites investigated were the precursors serotonin and N -acetyl-serotonin and the main breakdown product 6-hydroxymelatonin.
Methods The effect of the test substances on the in vitro oxidation of LDL (increase in conjugated diene formation) was investigated at concentrations of 1, 5, and 10  μm.
Results Melatonin increased the lag time of formation of oxidized LDL only at a concentration of 10  μm. In contrast, 6-hydroxymelatonin, serotonin and N -acetyl-serotonin as well as vitamin E showed inhibitory effects starting at 1  μm. Thus the antioxidative action of melatonin was negligible compared with the effect of its main metabolite, its precursors and of vitamin E.
Conclusions The present results indicate that the pineal hormone melatonin appears to have little antiatherogenic property as regards the oxidation of LDL. Its main breakdown product 6-hydroxymelatonin, however, inhibits LDL-oxidation comparable to vitamin E. The precursors of melatonin, N -acetyl-serotonin and serotonin may also play a role in the inhibition of LDL oxidation in vivo .     

Study of treatment of congenital Toxoplasma gondii infection in rhesus monkeys with pyrimethamine and sulfadiazine.

The efficacy of the combination of pyrimethamine and sulfadiazine for the treatment of congenital Toxoplasma gondii infection in rhesus monkeys was studied. The dosage regimen for pyrimethamine and sulfadiazine was established by pharmacokinetic studies in two monkeys. Those studies showed that the distributions of both drugs followed a one-compartment model. The serum elimination half-lives were found to be 5.2 h for sulfadiazine and 44.4 h for pyrimethamine. Sulfadiazine reached a maximum concentration in serum of 58.7 micrograms/ml, whereas a maximum concentration in serum of 0.22 micrograms/ml was found for pyrimethamine. Ten monkeys were infected intravenously with T. gondii at day 90 of pregnancy, which is comparable to the second trimester of organogenetic development in humans. Treatment was administered to six monkeys, in whose fetuses infection was diagnosed antenatally. From the moment that fetal infection was proven, the monkeys were treated throughout pregnancy with 1 mg of pyrimethamine per kg of body weight per day and 50 mg of sulfadiazine per kg of body weight per day orally. The therapy was supplemented with 3.5 mg of folinic acid once a week. No toxic side effects were found with this drug regimen. The parasite was no longer detectable in the next consecutive amniotic fluid sample, taken 10 to 13 days after treatment was started. Furthermore, T. gondii was also not found in the neonate at birth. The parasite was still present at birth in three of four untreated fetuses that served as controls. Both drugs crossed the placenta very well. Concentrations in fetal serum varied from 0.05 to 0.14 micrograms/ml for pyrimethamine and from 1.0 to 5.4 micrograms/ml for sulfadiazine. In addition, pyrimethamine was found to accumulate in the brain tissue, with concentrations being three to four times higher than the corresponding concentrations in serum. Thirty percent of the sulfadiazine was found to reach the brain tissue when compared with the corresponding serum concentration. when administered early after the onset of infection, the combination of pyrimethamine and sulfadiazine was clearly effective in reducing the number of parasites in the fetus to undetectable levels.     

A supra-annular malposition of the Perceval S sutureless aortic valve: the 'χ-movement' removal technique and subsequent reimplantation

The Perceval S sutureless valve prosthesis has recently been introduced as a new biological aortic valve prosthesis, but a specific learning curve is required, as for every cardiac surgical centre dealing with a new technique. After the removal of the stenotic valve, the prosthetic valve is correctly positioned within the mildly decalcified aortic annulus. When a supra-annular malposition occurs, due to an excessively rapid release of the prosthesis in the aorta or incomplete annular visualization, the Perceval S valve can safely be removed even after balloon dilation. The procedure performed is a 'χ-movement' with the aid of anatomical forceps. If the prosthesis does not show any malformation after the procedure, it can be reimplanted in the correct intra-annular position.