• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.187-193
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• 2010

In this study we have designed and fabricated an inexpensive micro electronic system that we call Alvitek. It can indirectly but accurately predict and display the partial pressures of alveolar oxygen and carbon dioxide for the patients in the ICU of a hospital. Alvitek consists of both hardware part and software part. Performance of the system is tested by animal experiment with pigs for various $F_{t}e_{2}$ and RR(Respiratory Rate) values under the mechanical ventilation. The predicted alveolar gas partial pressures are cprpared with the approximate alveolar oxygen partial pressures easily calculated by the physician’s bedside formula. As a result, we have concluded that the relative error of A-$aDe_2$ calculated by the bedside formula grows seriously for lower $F_{t}e_{2}$ values. The present prediction method of Alvitek is henceforth believed very meaningful to the physicians. The system hardware and software are described in the text.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.1-12
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• 1987

Respiratory care with oxygen inhalation is often a necessity to maintain life, and it is one of the important therapeutic adjuncts in respiratory disease and in intensive care after surgery. However, it has been reported that oxygen toxicity occurs after prolonged exposure to 100% 0, [Smith, 1899; Kistler et al. 1967; Schaffner et al. 1967; Rowland and Newman, 1969. Subjective symptoms of oxygen toxicity include tracheal irritation, frequent cough, some burning sensation in the trachea, tachypnea, severe dyspnea, etc. [Welch, 1963; Fisher et al, 1968; Milier et al, 1970; Clark and Lambertsen, 1971; Sackner, 1975]. Pathologic findings are atelectasis, injuries to the pulmonary capillaries and hemorrhage in the alveoli in gross specimens. There can be inflammation, proliferation of fibrin, thickening of alveolar membranes, degeneration of collagen fibers and interstitial edema in the microscopic findings. [Penrod, 1956; Cedergren, 1959; Bean, 1965; Schaffner, 1967]. Dubois and colleagues [1961] found that the amount of pulmonary surfactant was decreased in oxygen toxicity and atelectasis followed by the decreased pulmonary surfactant. Many authors reported that vital capacity, inspiratory force, pulmonary compliance, pulmonary capillary blood flow and pulmonary elasticity were deceased and arteriovenous shunting increased. [Comroe et al, 1945; Fuson et al, 1965; Kistler et al, 1966; Knowles and Blenner-hassett, 1967; Barber et al, 1978]. Many human volunteers were examined after prolonged exposure in a high oxygenated chamber and there were a few reports on animals with oxygen toxicity, subjects including rabbits. Gas partial pressures of alveoli and arteries were measured in rabbits exposed to 100% $O_2$ and the alveolar-arterial gas gradients were analyzed, which is the basis for the study of oxygen toxicity. These rabbits were divided into two groups; rabbits under natural respiration, and second group under artificial respiration with a respirator. The alveolar $PO_2$ [$P]AO_2$] and $PCO_2$ [$PACO_2$], and the arterial $PO_2$ [$PaO_2$] were measured under varying $O_2$ pressures; 15% $O_2$, 21% $O_2$ and 100% $O_2$.

• 순환기질환의공학회:학술대회논문집
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• 2005.12a
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• pp.21-22
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• 2005

• The Korean Journal of Physiology
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• v.1 no.1
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• pp.73-76
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• 1967

A nomogram of gas exchange ratio (R) in air breathing subjects ,was porposed which enables a simple and rapid determination of R value using the fractional concentrations of nitrogen and carbon dioxide in the expired or alveolar gas. The readable limit of R value seems less than 1/100 of R unit and the average difference between the values from the nomogram and the actually calculated values is less than 0.005 of R unit. The usefulness of this nomogram for rapid and frequent determinations of the oxygen uptake is also suggested.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.25-35
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• 1972

The author used a dog preparation, in which either the left lung or the lower left lobe rebreathed continuously from a bag, to compare $CO_2$ and $O_2$ tensions in the rebreathed gas with those in blood entering or leaving the lung. In the 10 dogs studied, alveolar pressures for both gases were greater than in the blood; the "upstream" gradient (alveolar pulmonary arterial blood) exceeded the "downstream" gradient (alveolar-pulmonary venous blood) for both gases, but the difference was only significant for $CO_2$. The author attributed this effect to the production of $CO_2$ in lung tissue metabolism and its uptake by the blood. The difference in $CO_2$ tension between blood leaving and entering lung increased while the downstream gradient fell, an effect which was independant of the level of anesthesia. There was no evidence of a fall in base excess in blood passing through the lung, as would occur from the production of metabolic acids during anaerobic metabolism at the low levels found in the rebreathing lung in this preparation.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.437-443
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• 1998

Pulmonary alveolar proteinosis is characterized by the accumulation of PAS positive lipoproteinaceous or amorphous proteinaceous material in the alveolar space with spared delicate septal architecture of the lung interstitium and impaired gas exchange of alveoli. We experienced a case of secondary pulmonary alveolar proteinosis in a 41 year old male patient who have occupational history of engagement as a mason over 4year. He compalined exertional dyspnea and chest discomfort, and presented fine inspiratory crackle at both lower lung field, numerous fine nodular denisties in both lung field with peripheral sparing. Light microscopic finding of lung tissue obtained by transbronchiallung biopsy revealed homogenous eosinophilic colloid-like luminal content in the alveolar space, and electron microscopy of bronchoalveolar lavage fluid concentrate showed electron-dense multilamellated structures. To treat the disease, we tried whole lung lavage of right lung with isotonic saline under general anesthesia. After whole lung lavage of right lung, he showed markid improvement of symptom and partial improvement of chest X-ray findings. The patient has been followed for 12 month until now, with no evidence of aggravation.

• Journal of Chest Surgery
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• v.5 no.2
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• pp.87-96
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• 1972

Studies of blood gas and lung histopathology were done in 10 dogs after intrapericardlal aorto-right pulmonary arterial anastomosis with proximal ligation of the right pulmonary antery. Among the 5 expired during or after operation, in 3 cases, the causes of the death were due to surgical bleeding and, in 2 cases, acute cardiopulmonary insufficiency because of large anastomosis stoma measured respectively 7mm and 10mm. In the 5 of survivals, one was sacrificed because of empyema at postoperative 7 days and 2 were at postoperative one month and remained 2 at postoperative 3 month respectively. The following observations were made. 1.In every survival, continuous machinary murmur was auscultated and the angiograms of all long term survivals showed the good patency of the anastomosis stoma. 2.After the ligation of the right pulmonary artery, the values of $PO_2$ and $PCO_2$ in arterial and venous blood were generally decreased comparing with the preoperative values. The mean value of $P_aO_2$ noted $83.30{pm}11.875$[p<0.01]. After the shunts operation with ligation of the right pulmonary artery, the immediate values of PH, $PO_2$ and $PCO_2$showed no significant changes comparing with that of right pulmonary artery ligation only. In the cases of survivals more than one month, the values of $PO_2$ and $PCO_2$ in the arterial and venous blood were generally higher than that of ligation of the right pulmonary artery only. The $P_aO_2$ value noted $103.750{pm}7.395$[p<0.01]. The mean values of $P_aO_2$, $PCO_2$ and PH in the arterial and venous blood almost returned to that of preoperative studies. 3.In the specimens of lung from the cadavors expired due to acute cardiopulmonary insufficiency after the operation, there were massive congestion, hemorrhage in the alveolar spaces and bronchioles. In specimens obtained at postoperative one month, there were dilatation of alveolar spaces with partial rupture, slight congestion, and alveolar wall thickening in the lung parenchyme, but there was no significant changes in pulmonary vasculature except dilation of pulmonary capillaries. In the specimens obtained at postoperative three months, the alveolar walls were more thickened in the lung parenchyme than the finding of the specimens obtained at postoperative one month. In the wall of pulmonary capillaries, there was only slight thickening with connective tissue proliferatlon.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.245-250
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• 2006

The effects of aliphatic hydrocarbons (n-hexadecane and n-dodecane) on the volumetric oxygen mass transfer coefficient $(k_L\;a)$ were studied in flat alveolar airlift reactor and continuous stirred tank reactors (CSTRs). In the flat alveolar airlift reactor, high aeration rates (>2vvm) were required in order to obtain efficient organic-aqueous phase dispersion and reliable $k_La$ measurements. Addition of 1% (v/v) n-hexadecane or n-dodecane increased the $k_La$ 1.55- and 1.33-fold, respectively, compared to the control (superficial velocity: $25.8{\times}10^{-3}m/s$, sparger orifice diameter: 0.5 mm). Analysis of the gas-liquid interfacial area a and the liquid film mass transfer coefficient $k_L$ suggests that the observed $k_La$ increase was a function of the media's liquid film mass transfer. Addition of 1% (v/v) n-hexadecane or n-dodecane to analogous setups using CSTRs led to a $k_La$ increase by a factor of 1.68 and 1.36, respectively (superficial velocity: $2.1{\times}10^{-3}m/s$, stirring rate: 250 rpm). These results propose that low-concentration addition of oxygen-vectors to aerobic microbial cultures has additional benefit relative to incubation in purely aqueous media.

• Journal of Chest Surgery
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• v.23 no.6
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• pp.1084-1089
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• 1990

Plasma protein concentration, plasma albumin concentration, hematocrit, and arterial blood gas tension were measured in 15 mongrel dogs undergoing heart transplantation with cardiopulmonary bypass. The hemodilution due to priming solution resulted in a 49% decrease in plasma protein concentration, a 57% decrease in plasma albumin concentration, a 46%a decrease in hematocrit. The measurements had returned to preperfusion values 1 hour after the end of cardiopulmonary bypass. The intraoperative changes in plasma protein and albumin concentration did not correlate with changes in alveolar-arterial oxygen tension gradients[D[A\ulcorner PO2]]. It is concluded that, in the absence of an increase in left atrial pressure, marked decrease in plasma protein concentration can be tolerated without the occurrence of pulmonary edema. And further study should be done to determine how to prepare an ideal priming solution.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.37-50
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• 1972

Another comparison of alveolar gas pressures, in a continuously rebreathing dog lung, with pulmonary arterial (mixed venous) blood, again showed alveolar pressures to be the higher for $CO_2$ and usually $O_2$ (positive ${\Delta}Pco_2$, and ${\Delta}Po_2$). ${\Delta}Pco_2$ was almost invariably positive, it was independant of time and of plasma pH changes produced by acid or bicarbonate infusion, but proportional to blood $CO_2$ level. It was seemingly little affected by the distribution or magnitude of blood flow nor did it result from failure of $CO_2$ equilibrium within the blood, but it did rise with carbonic anhydrase inhibition. ${\Delta}Po_2$ was more variable and sometimes negative, particularly at low blood flow rates. It seemed in dependant of time, and plasma pH changes, apart from an inverse relationship with that resulting from $CO_2$ changes. It existed despite considerable potential for gas exchange, and was unaffected by inhibition of the $CO_2$ reactions.