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Biomedical subjects

S Ramanathan

Publications and source records attributed to S Ramanathan.

At least 19 recordsLinked to original sources
PubMed1979

Humidity and the anesthetized patient.

Damage to the ciliated cells of the tracheobronchial tree and incidence of postoperative pulmonary complications were measured by point-scoring systems in 202 patients who breathed dry and humidified anesthetic gases for 225 +/- 78 min. The incidence of postoperative pulmonary complications decreased as the humidity of administered anesthetic gases increased from 0 to 32.5 mg H2O/l. A similar relationship was found between the amount of inhaled moisture and the damage to the ciliated epithelium of the tracheobronchial tree. These results appear to indicate that a high inspired humidity is beneficial for operations on normothermic patients, and that cellular damage caused by dryness is a possible contributory factor in the production of the pulmonary atelectasis that follows stoppage of the mucociliary transport system in the immmediate postoperative period.

Adolescent↗
PubMed1979

An improved program to calculate intrapulmonary shunting.

A computer program was developed to calculate intrapulmonary venous admixture on a Texas Instruments TI 59 programmable calculator. The program incorporates the following characteristics: 1) a correction for saturated water vapor pressure which varies with body temperature; 2) a mathematical model of the standard oxyhemoglobin dissociation curve; and 3) correction factors for shifts of the dissociation curve due to variations in pH and carbon dioxide tension. It also corrects oxygen tensions obtained at electrode temperature to those at patient temperature, and calculates variations of the Bunsen solubility coefficient of oxygen in blood with body temperature.

Bionics↗
PubMed1978

A high-humidity circle system for infants and children.

A scaled-down version of a modified adult circle system capable of increasing normal humidity output 300% was constructed for pediatric use. The moisture content of the gases leaving the system was tested and found to be superior to that of any pediatric circle system commercially available that does not incorporate an electrically heated water vaporizer.

Anesthesia↗
PubMed1978

Tracheobronchial cytologic changes in malignant melanoma.

Histiocytes counted in smears made from the tracheobronchial washings of 208 patients with malignant melanomas were found to be 3.12 times more numerous than in a control group comparable in sex, age (decades), and smoking habit but without any type of prediagnosed malignant lesion. The discovery of this phenomenon may lead to the development of a new method for the evaluation of therapeutic methods in patients with melanotic lesions. It may open novel pathways for the investigation of cell-mediated immunity in patients with certain forms of malignant disease.

Adolescent↗
PubMed1975

Determining patency of palmar arches by retrograde radial pulsation.

The patency of palmar arches must be ascertained before radial-artery cannulation is performed. A simple test in which digital pulsation is felt after proximal occlusion of the radial artery has been devised for that purpose. The method is reliable, does not require active patient cooperation, and can be carried out in all clinical situations where the radial artery can be felt.

Arteries↗
PubMedDate not supplied

Thermometric estimation of carbon dioxide output in the anesthetized patient.

A thermometer reaching the center of an experimental thermally-insulated lime container, placed in the exhalation limb of a Foregger circle system, was used to measure the carbon dioxide (C02) output of a paralyzed anesthetized patient. Fresh gas inflow, ventilatory rate, and tidal volume were standard. Temperature rise in the canister was found closely related to CO2 output, which was calculated, after a period of stabilization, with the help of a nomogram. The results with this simple instrument coincided with those of more complex procedures.

Anesthesia, Inhalation↗
PubMedDate not supplied

Rebreathing characteristics of the Bain anesthesia circuit.

The humidity output and CO2 elimination of the Bain circuit were tested on a simulated adult patient. The moisture content of inspired gases was found to be adequate when the circuit was used with a minute volume of 8.4 L/min and a fresh gas inflow of 4.9 L/min (65 percent relative humidity at room temperature at the onset of experimentation, rising to 100 percent after 80 minutes). However, the mean inspired CO2 concentration increased from 0.8 percent to 5.5 percent when the fresh gas inflow was decreased from 8 L/min to 3.5 L/min. It is recommended, therefore, that the circuit should not be used for long periods of time without measuring arterial CO2 tension or in situations where intentional hypocarbia is desired.

Adult↗