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Biomedical subjects

J H Modell

Publications and source records attributed to J H Modell.

At least 55 records · Page 3Linked to original sources

Evaluation of criteria for discontinuing mechanical ventilatory support.

Thirty-three patients who required short-term postoperative mechanical ventilatory support were studied to compare different criteria established to initiate weaning from mechanical ventilation. Intermittent mandatory ventilation criteria (i.e., decreasing mechanical respirator rate as long as the arterial (pHa) remains above 7.35) and conventional criteria (ie, vital capacity greater than 15 ml/kg and peak negative pressure greater than 20 cm H2O) were compared to determine which would more rapidly predict a patient's ability to sustain total spontaneous respiration. All patients were eventually weaned from mechanical ventilation and had their tracheas extubated. Twenty-one patients maintained a pHa of greater than 7.35 during total spontaneous ventilation before they would, or could, meet conventional criteria for initiating a trial of spontaneous respiration (P less than .001). Seven patients simultaneously met both criteria for maintaining total spontaneous ventilation and the remaining five patients met conventional criteria before intermittent mandatory ventilation criteria. In the latter group, the pHa decreased below 7.35 during spontaneous respiration but in only one patient did it fall below 7.30. Our findings suggest that a patient's ability to maintain a pHa of greater than 7.35 while decreasing the frequency of mechanical ventilator breaths is more accurate than peak negative pressure and vital capacity for predicting ability to sustan adequate spontaneous respiration.

Adolescent↗

Biology of drowning.

The near-drowning victim must be treated immediately for ventilatory insufficiency, hypoxia, and the resulting acidosis. The cause and pathophysiologic changes of pulmonary insufficiency vary, depending on the tpe and volume of fluid aspirated. Success or failure of the overall resuscitative effort frequently depends on the adequacy of prompt emergency resuscitation and on effective intensive pulmonary care. Each patient should be evaluated and treated individually, since abnormalities of multiple organ systems can occur, their degree and form varying considerably from patient to patient (28).

Acid-Base Equilibrium↗

Near drowning.

Explore the source record for details and available documents.

Blood Gas Analysis↗

Respiratory aspiration of stomach contents.

The aspiration of stomach contents is a common clinical problem of concern to all physicians. Its consequences are varied, depending on the amount and distribution of the aspirate, its pH, and the presence or absence of food, particulate matter, and bacteria. Because multiple factors are involved, aspiration of stomach contents can lead to several distinct syndromes of pulmonary injury, all of which unfortunately have been labeled "aspiration pneumonitis." We review the pathophysiology of each of these syndromes and discuss important diagnostic and therapeutic consequences.

Adrenal Cortex Hormones↗

Liquid ventilation of primates.

Three adult monkeys were anesthetized with ketamine and ventilated with fluorocarbon liquid [perfluoro bis (1, 4-isopropoxy) butane (Caroxin-D)] at 1 atmosphere on two separate occasions. During five runs, liquid ventilation was continued for 60 minutes. The sixth run was continued for ten minutes. Arterial blood gas levels during and after liquid ventilation were adequate for survival. Three years after the first period of liquid ventilation, the animals were killed. Approximately 0.001 mg of fluorocarbon per gram of tissue was present in the kidney, liver, brain, spleen, muscle, and heart. Fat contained approximately seven to nine times this amount, and the lung and pulmonary lymph nodes contained approximately 1,000 times this amount. In no case was it clinically evident that the monkeys had undergone periods of liquid ventilation. We conclude that primates can be ventilated successfully with liquid fluorocarbon on at least two separate occasions and can return to breathing air without obvious deleterious effects, but fluorocarbon is retained in small amounts for at least three years.

Adipose Tissue↗

Clinical course of 91 consecutive near-drowning victims.

Hospital records of 91 consecutive near-drowning victims were studied retrospectively. Eight-one (89 percent) of these patients survived. Patients who were alert on arrival at the emergency room survived, but those who were comatose and had fixed dilated pupils died. Other states of consciousness were unreliable predictors of survival. All patients with a normal chest roentgenogram on admission survived; however, values for arterial oxygen tension (PaO2) did not necessarily correlate with the chest roentgenograms. Values for arterial blood gas tensions and pH varied widely, as follows; PaO2, 25 to 465 mm Hg; arterial carbon dioxide tension (PaCO2), 17 to 100 mm Hg; pH, 6.77 to 7.50; and arterial bicarbonate level, 6.6 to 29.7 mEq/L. The ratio of PaO2 to the fractional concentration of oxygen in the inspired gas (FIo2), which was calculated to standardize PaO2 data for varying concentrations of inspired oxygen, ranged from 30 to 585 mm Hg. Only one patient with a ratio of PaO2/FIo2 greater than 150 mm Hg on admission subsequently died; this was a neurologic rather than a pulmonary death. Serum electrolytic concentrations and values for hemoglobin level and hematocrit reading neither predicted survival nor indicated that a threat to life existed. Steroid and prophylactic antibiotic therapy did not appear to increase the chance of survival. Observations on these patients are discussed in light of previous experiments in animals, and an approach to therapy is suggested.

Adolescent↗

Treatment of chronic pain with acupuncture.

We performed 979 acupuncture treatments in 261 patients with chronic pain. A substantial number of patients stated that they had relief immediately following a series of four acupuncture treatments. It did not matter whether the needles were placed in the traditional meridian locations of in arbitrary fixed control points. Four weeks following treatment, 65% of the patients reported little or no reduction in the intensity of their pain, 17% reported a 50% reduction, and 18% at least a 75% reduction.

Acupuncture Therapy↗

Treatment of flail chest. Use of intermittent mandatory ventilation and positive end-expiratory pressure.

For the past two years we have treated patients with flail chest injuries and concomitant respiratory failure with intermittent mandatory ventilation (IMV) and positive end-expiratory pressure (PEEP). Prior to 1972 these patients were treated with controlled mechanical ventilation (CMV) until gross flailing ceased and inspiratory force and vital capacity measurements were adequate. We retrospectively studied the charts of 37 consecutive patients to compare the length of mechanical ventilatory support of patients managed by conventional CMV with those ventilated with IMV and PEEP. The mean ventilation time of patients treated with IMV and PEEP (5.1 +/- 4.7 days) was significantly less than that of the patients treated with CMV (18.8 +/- 14.4 days) (P less than .001).

Accidents, Traffic↗

The ineffectiveness of steroid therapy for treatment of fresh-water near-drowning.

The authors evaluated the efficacy of continuous positive-pressure ventilation (CPPV) and methylprenisolone alone and in combination as therapy for near-drowning in 80 dogs that had aspirated distilled water (22 ml/kg or 44 ml/kg). Forty dogs were treated with mechanical ventilation for one hour and 40 for 24 hours. Blood-gas tensions, pH, cardiac output and intrapulmonary shunt (Qs/Qt) were measured frequently for 24 hours. Blood-gas tensions and pH were again measured 48 and 72 hours and seven days later in survivors. Arterial oxygen tension (PaO2) decreased and Qs/Qt increased in all animals following aspiration and before therapy. Forty dogs received methylprednisolone intravenously (30 mg/kg) (20 breathed spontaneously and 20 had CPPV). There was a significant increase in PaO2 and decrease in pulmonary shunt in dogs that were ventilated mechanically compared with animals that breathed spontaneously. Treatment with methylprednisolone made no difference in blood gases, pulmonary shunt, or survival rates. Thus, no evidence to support the use of methylprednisolone in the treatment of the pulmonary lesion of fresh-water near-drowning was found. (Key words: Drowning, fresh-water; Hormones, adrenal, methylprednisolone.)

Adrenal Cortex Hormones↗

Residual levels and biochemical changes after ventilation with perfluorinated liquid.

Twenty-three beagle dogs were ventilated with perfluorinated liquid, perfluoro-1-isopropoxy-hexane (Caroxin-F) for 1 h and were reconverted to gaseous breathing. Hematologic and biochemical changes were studied in five dogs for 1 yr and the remaining animals were followed for evidence of retained Caroxin-F for up to 3 yr. We found that the dogs could be ventilated with liquid Caroxin-F and returned to spontaneous breathing of gaseous oxygen with normal blood gas exchange within 24-72 h. Serum alkaline phosphatase, serum cholesterol, and white blood cell count increased with liquid ventilation but returned to normal in less than 1 wk. Trace amounts of Caroxin-F were detected by chromatography in all tissues studied for the entire 3-yr period. The highest levels of Caroxin-F were found in the lungs and associated lymph nodes. No histologic evidence of the presence of Caroxin-F was seen except for local accumulations of vacuolated macrophages in the lungs and associated lymph nodes. We conclude that Caroxin-F can be breathed without residual deleterious effects, even though trace amounts remained for at least 3 yr.

Alkaline Phosphatase↗

High level positive end expiratory pressure (PEEP) in acute respiratory insufficiency.

Twenty-eight patients developed severe, progressive acute respiratory insufficiency despite aggressive application of conventional respiratory therapy. Application of increased PEEP (18 torr or greater) resulted in a significant decrease in QA/QT. Selection of the optimal levle of PEEP for each patient required serial determinations of QA/QT and measurement of cardiovascular response. The overall survival rate was 61 percent. Acute respiratory insufficiency was a proximate cause of death in only one patient. Four of the patients (14 percent) developed a pneumothorax following institution of high PEEP therapy. Cardiac output was not affected adversely at any level of PEEP up to 32 torr (44 cm H2O). We conclude that high levels of PEEP can be therapeutic for patients with refractory respiratory failure when combined with intermittent mandatory ventilation and careful cardiovascular monitoring. As with any therapy, the optimum dose should be tailored to each patient according to his needs and response.

Acute Disease↗