Balloon occlusion of the right main bronchus in an ovine model provides sufficient time for emergent interventions in massive pulmonary embolism.

PURPOSE: Massive pulmonary embolism (PE) causes hemodynamic compromise and is associated with a high rate of mortality. We sought to create a model of massive PE and to determine whether occlusion of the right main bronchus could mitigate the physiological effects of massive PE in this model. MATERIALS AND METHODS: We used 27 female sheep to generate a model of massive PE by either autologous blood clot injection (n=18) or detachable balloon release (n=9) into the right main pulmonary artery. Four sheep were excluded after blood clot injection, as they did not exhibit adequate declines in blood oxygen saturation (SaO(2)). Nine of the sheep that received autologous blood clot and nine that received detachable balloons went on to treatment with right main bronchus occlusion. The control group (n=5) received the autologous blood clot, but no occlusion of the right main bronchus. All sheep underwent continuous monitoring of pulmonary arterial mean pressure (PAMP), SaO(2), arterial partial pressure of oxygen (PaO(2)), and arterial partial pressure of carbon dioxide. RESULTS: Twenty-three sheep (85%) subjected to PE demonstrated immediate tachycardia, tachypnea, and decline in SaO(2) of at least 25% within 30 min. After right main bronchus occlusion, 18 sheep (100%) survived for the length of the experiment and exhibited persistently higher SaO(2) and PaO(2) levels, as well as decreased PAMP compared with the controls. In the control group, two out of five sheep died within 30 min, and the three surviving subjects demonstrated significantly decreased SaO(2) and PaO(2) levels. CONCLUSION: Occlusion of the right main bronchus in an ovine model of massive PE effectively extends life and provides favorable physiological parameters to allow emergent interventions.

Prevention of iodinated contrast-induced nephropathy.

OBJECTIVE: To lessen the occurrence of contrast-induced nephropathy (CIN), the preventive measures of CIN were reviewed. DATA SOURCES: The data used in this review were from PubMed with relevant English articles and from Chinese Knowledge Information (CNKI) published from 1989 to 2009. The search terms were "contrast medium", "contrast-induced nephropathy" and "prevention". Articles involved in prevention of CIN were selected. STUDY SELECTION: CIN is the third most common cause of acute kidney injury and is associated with an unfavorable prognosis. The best treatment is prophylaxis because CIN can not be reversed or ameliorated. RESULTS: Thirty articles were included. Among various preventive measures, pericatheterization hydration is almost universally accepted as an appropriate and safe measure to prevent CIN, although there is no agreement as to composition, amount, and timing of hydration. Based on the use of concomitant nephrotoxic agents or high doses of contrast medium (CM) is one of risk factors for CIN, discontinuation of potentially nephrotoxic drugs 2 - 3 days before and after the procedure until renal function recover, and using the lowest possible dose of CM can decrease the risk of CIN. It is promising that removing the majority of CM from the coronary sinus, before it enters the systemic circulation, during coronary angiography can reduce the risk for CIN in animal studies and in limited clinical trials. Inconsistent data exist with respect to application of some vasodilators (endothelin antagonists and adenosine antagonists) and antioxidants (N-acetylcysteine and statins) in preventing CIN in high-risk patients, and new vasodilators and antioxidants continue to be tested. CONCLUSIONS: Pericatheterization hydration, discontinuation of nephrotoxic drugs, and using the lowest possible dose of CM are effective measures to lessen the risk for CIN. Other prophylactic strategies and some drugs are promising, but further confirmation is required.

[Comparison of the massive pulmonary embolism of the animal model stabled by different methods].

OBJECTIVE: To contrast the massive pulmonary embolism of the animal model had been stabled by inserting the animal's own blood clots or through use of detachable latex balloons. METHODS: Eighteen healthy sheep were separated as three groups with random. We established the animal lung, PE model by inserting the animal's own blood clots at right lung artery in 6 sheep, and 6 sheep were through used of detachable latex balloons to substitute the blood clots. Six healthy sheep were used as controls. Each sheep was anesthetized. Both sides of the region inguinalis were applied 21 transfixion pins to one femoral artery and two femoral veins on the left side, and one femoral vein on the right side. All vessels were inducted into the 5 F vagina vasorum except one vein for which 12 F was inducted. 50 ml blood was taken from vagina vasorum from each animal and stabilized for 2 h for later use as a body blood clot. Guided and visualized by X-ray, a 5 F pigtail catheter was inserted on the left side to measure arterial pressure, central venous pressure and pulmonary arterial pressure; a 12 F guiding catheter was then inserted through right side femoral vein into the right lung artery to inject 8 ml 350 mg I ultravist at 6 ml/s for pulmonary arteriography, After the animal was stabilized for 30 min, we input their own body blood clots (0.6 ml/kg) using a 12 F guiding catheter or, alternatively, to release a self-made, detachable latex balloon. We measured arterial pressure, central venous pressure, pulmonary arterial pressure, heart rate, blood oxygen saturation, partial pressure of oxygen in artery and partial pressure of carbon dioxide in artery etc. of the animals both immediately before inputting their own body blood clots or detachable latex balloons, immediately afterwards, immediately before interfering with airflow and at 3 min, 6 min, 10 min, 15 min, 20 min, 30 min, 45 min and 60 min after the interference. RESULTS: Heart and breath rates of all 12 sheep increased, blood oxygen saturation and partial pressure of oxygen in artery decreased, and pulmonary arterial pressure increased after inputting their own body blood clots or inserting latex balloons with statistical significance that were compared with controls. Blood oxygen saturation decreased, on average, by more than 25% within 30 min. Two hours after, all 12 experimental animals showed stable. Index of sheep in latex balloons group were increased slowly but stabilized at a lower level in blood clots group with statistical significance. CONCLUSION: This animal experiment demonstrates that balloon can establish a physico- affection and blood clot can establish a chemical action for massive PE.