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Biomedical subjects

T Kolobow

Publications and source records attributed to T Kolobow.

At least 55 records · Page 3Linked to original sources
PubMed1984

The role of total static lung compliance in the management of severe ARDS unresponsive to conventional treatment.

A group of 36 patients with severe adult respiratory distress syndrome (ARDS) meeting previously established blood gas criteria (mortality rate 90%) became candidates for possible extracorporeal respiratory support [low frequency positive pressure ventilation with extracorporeal CO2 removal (LFPPV-ECCO2R)]. Before connecting the patients to bypass we first switched the patients from conventional mechanical ventilation with positive end expiratory pressure (PEEP) to pressure controlled inverted ratio ventilation (PC-IRV), and then when feasible, to spontaneous breathing with continuous positive airways pressure (CPAP). Forty eight hours after the patients had entered the treatment protocol, only 19 out of the 36 patients in fact required LFPPV-ECCO2R, while 5 were still on PC-IRV, and 12 were on CPAP. The overall mortality rate of the entire population was 23%. The only predictive value of success or failure of a particular treatment mode was total static lung compliance (TSLC). No patients with a TSLC lower than 25 ml (cm H2O)-1 tolerated either PC-IRV or CPAP, while all patients with a TSLC higher than 30 ml (cm H2O)-1 were successfully treated with CPAP. Borderline patients (TSLC between 25 and 30 ml (cm H2O)-1) had to be treated with PC-IRV for more than 48 h, or were then placed on LFPPV-ECCO2R if Paco2 rose prohibitively. We conclude that TSLC is a most useful measurement in deciding on the best management of patients with severe ARDS, unresponsive to conventional treatment.

Adolescent↗
PubMed1984

Respiratory distress syndrome in immature lambs. Prevention through antenatal accelerated conditioning of the lung.

We tested the effectiveness of constant distending pressure applied to immature lungs in preventing respiratory distress syndrome. Fetal lambs of 131 to 134 days gestation were delivered by cesarean section, but the umbilical circulation was kept intact for CO2 removal through the natural in situ placenta. The lungs were inflated to a pressure of 35 cm H2O (Group I, 11 animals) or 25 cm H2O (Group II, 14 animals), after which the airway pressure was maintained at 15 cm H2O through apneic oxygenation until total static compliance exceeded 0.5 ml (cm H2O)- 1kg -1. After a mean of 1.1 and 5.7 h, respectively, the animals were delivered and were given mechanical ventilation for 24 h. Twenty-four animals reached this aimed-for compliance and survived the period of mechanical ventilation in excellent health. A control group of fetal lambs was delivered immediately and treated with mechanical ventilation. Three of 10 control animals developed severe respiratory distress syndrome and died; 1 additional animal survived but with central nervous system involvement from severe hypoxia. We conclude that pulmonary inflation to 35 cm H2O pressure, followed by a constant distending pressure of 15 cm H2O, held until compliance reaches 0.5 ml (cm H2O)- 1kg -1, is an important element in the prevention of respiratory distress syndrome.

Animals↗
PubMed1984

Extracorporeal gas exchange, lung transplantation, and the artificial lung.

The potential for lung damage from mechanical ventilation may be much greater than has been realized in the past. Prior studies of extracorporeal support in adults were carried out after patients had been subjected to high airway pressure and hyperventilation for several days. The studies by Gatinoni supported by Kolobow would suggest that earlier application of extracorporeal gas exchange to remove CO2 may be more effective in salvaging the lung, particularly if applied before ventilator-induced lung damage has occurred. These challenging studies, combined with the successful application of extracorporeal support in infants, should stimulate new investigations of extracorporeal support in adult respiratory failure. Extracorporeal support may be a valuable adjunct to lung transplantation if transient pulmonary failure occurs following that operation. However, lung transplantation for acute respiratory failure in a patient who is being supported with ECMO is not recommended. The feasibiilty of an implantable lung has been demonstrated in animals for short periods of time. Continuing studies in this area should be encouraged, particularly before the establishment of a lungless animal preparation to determine some of the nonrespiratory functions of the lung.

Animals↗
PubMed1983

Management of the antenatal preterm fetal lung in the prevention of respiratory distress syndrome in lambs.

We have explored change in pulmonary compliance before, and after, repeated deep insufflation of the lungs to a pressure of 35 cm H2O, in 130-days gestation fetal lambs delivered by cesarean section, and while still connected to the intact umbilical cord and the ewe. As a group, all 15 out of 28 fetal lambs that had a rise in total compliance to above 0.2 ml (cm H2O)-1 kg-1 after the first inflation, tolerated 24 h of mechanical ventilation with excellent health and good lung function; only 3 animals out of 13 that showed no similar initial rise in compliance after the first inflation, ultimately survived. We believe the first deep insufflation is an important therapeutic intervention and a useful index to rapidly assess chance of survival in a high-risk fetal lamb population.

Animals↗
PubMed1982

Prevention of hyaline membrane disease in premature lambs by apneic oxygenation and extracorporeal carbon dioxide removal.

Hyaline membrane disease is found only in lungs where pulmonary ventilation has been established, i.e. after birth. We delivered eleven fetal lambs of a gestational age of 128-130 days but instead kept their lungs in total apnea and inflated to constant pressure, while removing all metabolically produced carbon dioxide with an extracorporeal membrane lung. Oxygen was provided by the membrane lung, and by apneic oxygenation through the natural lungs. Hence, arterial blood gases remained always normal, without any pulmonary ventilation. After 6-66 h the lungs had sufficiently cleared to allow normal mechanical pulmonary ventilation in 10 our of 11 lambs so treated. In a control group treated with mechanical ventilation alone, five of seven lambs died within the first 24 h of severe hyaline membrane disease.

Animals↗
PubMed1981

Massive pulmonary infarction during total cardiopulmonary bypass in unanesthetized spontaneously breathing lambs.

We provided total cardiopulmonary support for 1-18 hours in unanesthetized tethered lambs by peripheral vascular cannulation, using a roller pump and the spiral membrane lung. Respirations were allowed to remain spontaneous and unaided. A Swan-Ganz catheter was placed for retrograde pulmonary artery blood flow sampling. Within a few minutes following induced ventricular fibrillation the PCO2 of sampled blood flowing retrograde through the lungs fell below 10 mm Hg, the PO2 rose to near 150 mm Hg, the pH rose to above 7.8, and the glucose level fell to less than 20 mg %. All of these values later gradually shifted, approaching mixed venous blood values within minutes. After 1-18 hrs of perfusion the animals went into shock and were sacrificed. At autopsy, the lungs of animals breathing room air were beefy and hemorrhagic. In lambs that were "breathing" CO2 enriched air the retrograde pulmonary artery blood pH and PCO2 was usually maintained close to the mixed venous blood values. The observed pulmonary changes were considerably less abnormal, and the microscopic abnormalities were at times nonexistent. We believe the integrity of pulmonary blood flow is vital to the survival of the lungs as a functioning organ. Cessation of total forward pulmonary blood flow (unlike partial cardiopulmonary bypass), combined with spontaneous pulmonary ventilation, rapidly leads to massive, pulmonary infarctions, shock, and death.

Alkalosis, Respiratory↗
PubMed1980

Treatment of acute respiratory failure with low-frequency positive-pressure ventilation and extracorporeal removal of CO2.

Terminal respiratory failure was reversed in three patients with a combination of extra-corporeal CO2 removal through a membrane lung and oxygen diffusion into the diseased lungs between mechanical breaths induced at a frequency of 2-3/min. The technique seems to prevent the pulmonary barotrauma and extrapulmonary derangements caused by conventional mechanical ventilation.

Acute Disease↗
PubMed1980

The prevention of hyaline membrane disease (HMD) in the preterm fetal lamb through the static inflation of the lungs: the conditioning of the fetal lungs.

Preterm fetal lambs of a gestational are highly susceptible to hyaline membrane disease were placed on apneic oxygenation while keeping the umbilical circulation intact and still connected to the mother ewe for the removal of metabolically produced CO2. After 4-6 hrs the total lung compliance and the chest x-ray films had markedly improved, allowing normal pulmonary ventilation with a mechanical ventilator. Fetuses older than 135 days gestation were later extubated and allowed to breathe room air unassisted. Fetuses 134 days gestation and younger were kept on mechanical ventilation. None of the animals so treated developed hyaline membrane disease. We believe pulmonary conditioning is an important tool in the prevention and the treatment of hyaline membrane disease. In this animal model we have shown that hyaline membrane disease is a preventable and curable disease.

Animals↗