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Biomedical subjects

F R Lewis

Publications and source records attributed to F R Lewis.

At least 73 records · Page 4Linked to original sources
PubMed1982

Indicator dilution using a fluorescent indicator.

In vitro and in vivo indicator-dilution measurements are made with a fluorescent indicator and a novel detection system using a catheter containing a single optical fiber that carries both the exciting and returning fluorescent light. These fluorescent-dilution measurements are compared with simultaneous green dye-dilution measurements. The double-indicator-dilution measurement of extravascular lung water using heat and fluorescence is compared with gravimetric measurements. Also investigated is the sensitivity of the fluorescent measurement to changes in O2 saturation and hematocrit of the blood. An example of the measurement of a right-to-left heart shunt with this new indicator is given.

Animals↗
PubMed1980

Epidemiology of trauma deaths.

The records of all 437 persons who died from trauma in San Francisco in 1977 were examined. Sixty-five percent of the sample (285 younger than 50 years, and 119 were between ages 21 and 30. Gunshot wounds (140 or 32 percent) and falls (122 or 28 percent) were the most common causes of injury. Fifty-three percent of the sample were dead at the scene of injury before transport could be accomplished, 7.5 percent died in the emergency room, and 39.5 percent died in the hospital. Fifty-five percent of the 359 patients who died within the first 2 days died from brain injury, while 78 percent of the 55 late deaths were due to sepsis and multiple organ failure. In 10 cases (2 percent), death was due to delayed transport or to errors in diagnosis and treatment and was deemed preventable. The key areas in which advances are necessary in order to reduce the number of trauma deaths are prevention of trauma, more rapid and skilled transport of injured victims, better early management of primary brain injuries, and more effective treatment of the late complications of sepsis and multiple organ failure.

Adolescent↗
PubMed1980

Chest trauma.

Explore the source record for details and available documents.

Airway Obstruction↗
PubMed1980

Lung water changes after thermal injury. The effects of crystalloid resuscitation and sepsis.

Respiratory failure after thermal injury is common, but the etiologic roles of high volume crystalloid resuscitation, hypoproteinemia, inhalation injury, or sepsis have not been specifically defined in human studies. We used the thermal-green dye double indicator dilution measurement of extravascular lung water (EVLW) to follow daily lung water changes in seven severly burned adult patients, resuscitated with only crystalloid solutions. An average weight gain of 21.3 kg, a 30% increase (p < 0.001), was present two to three days after admission. Admission EVLW for all patients was 7.9 +/- 1.2 ml/kg, (means +/- SD), and EVLW at the time of maximal weight gain was 5.9 +/- 1.4 ml/kg, a 25% decrease (p < 0.05). Admission pulmonary artery wedge pressure (PAWP) was 8 +/- 3 mmHG, which was not significantly different from PAWP of 13 +/- 4 mmHg at the time of maximal weight gain. In the three patients who died of sepsis, their terminal weight averaged 17.8 kg (27%) above their admitting weight (p < 0.01) and EVLW was 26.4 +/- 4.4 ml/kg, a 200% increase (p < 0.02) from admission. Their terminal PAWP averaged 22 +/- 2 mmHg, a 170% increase (p < 0.005). None of these patients had an increase in EVLW until clinical signs of sepsis occurred and the rise in EVLW preceded the rise in PAWP. Calculated mean plasma colloid osmotic pressure (PCOP) on admission was 20.7 +/- 4.9 mmHg; at the time of maximal weight gain, it was 8.6 +/- 1.7 mmHg (p < 0.001). The PCOP-PAWP gradient fell to -4 +/- 4 mmHg (p < 0.001) at the time of maximal weight gain and remained less than +4 mmHg throughout the study period in all patients. We conclude that massive crystalloid resuscitation while maintaining PAWP below 15 mmHg does not cause an increase in EVLW during the first four days after thermal injury. EVLW actually decreases slightly in all patients despite marked weight gain, hypoproteinemia and a negative PCOP-PAWP gradient. EVLW does not correlate with the PCOP-PAWP gradient in either septic or nonseptic periods. Three patients had severe inhalational injury and normal EVLW for the first four postburn days. It therefore appears that significant interstitial edema does not result from inhalational injury. There is also no evidence that thermal injury causes an early increase in pulmonary capillary permeability. The occurrence of sepsis, however, results in rapid accumulation of lung water, without any change in hydrostatic or osmotic forces. This study supports the primary role of sepsis in altering pulmonary capillary permeability with resulting pulmonary edema.

Adult↗
PubMed1980

Autopsy of a disaster: the Martinez bus accident.

On 21 May 1975 a chartered bus carrying 51 members of a student choir rolled from a sharply curved freeway off-ramp and fell 22 feet, landing on its roof, which collapsed. Twenty-nine passengers died (25 before extrication) and 22, plus the driver, survived. An analysis of factors leading up to the accident reveals several contributing causes, among them inadequate design of the ramp, poor warning signs, driver inexperience with the bus, and deficient bus maintenance. Bus design itself contributed to the lethality of the event. Structural support for the roof was inadequate and no access was available to the interior for extrication of victims. Problems with organization at the scene, triage, and communications among agencies involved in the rescue and receiving hospitals contributed to confusion in the transport of victims, although it appears this had little impact on outcome. An analysis of the accident allows several lessons to be learned which might prevent, or reduce, the fatalities from future accidents involving multipassenger vehicles, and other disasters with 10 to 25, or more than 25 fatalities. In the present report ten of 25 killed were judged possibly salvageable with immediate extrication.

Accidents, Traffic↗
PubMed1980

[Extravascular lung water in traumatic shock of the dog (author's transl)].

Fourteen dogs underwent standardized traumatic hemorrhagic shock. Periodically, measurement of extravascular lung water (EVLW) was taken by thermo-green-dye dilution technique and related to microvascular pressure (MVP) values. An initial drop in EVLW, corresponding to MVP was seen. During shock time the EVLW rose again, while the MVP remained at low levels. This shows a permeability leak during shock time.

Animals↗
PubMed1979

Cardiopulmonary parameters and prognosis after severe multiple trauma.

Comprehensive cardiopulmonary and metabolic monitoring of severely traumatized patients for 7 days from the time of injury has allowed us to determine parematers which correlate with survival and nonsurvival. The earliest and most persistent change is an increased pulmonary vascular resistance which results in right heart overload and failure. Left heart "failure" which has been previously described with acute respiratory failure and shock is shown to be a mathematical artifact caused by dilatation of the right heart and encroachment on left ventricular filling volume. Causes of death in most patients were not directly referable to right heart dysfunction but we postulate that hypercoagulability and microembolism could independently produce the observed pulmonary vascular changes as well as the multiple organ failure which usually was responsible for death. Resolution of this question will require more sophisticated hematologic evaluation.

Adolescent↗
PubMed1979

[Bedside determination of extravascular lung water].

Extravascular lung water (EVLW) was measured at the bedside in 12 patients with the thermal-green dye double indicator dilution method using a microprocessor. The EVLW ranged from 3.3 to 17.2 ml/kg body weight; in patients without pulmonary problems we have found an average EVLW of 5.7 ml/kg body weight. The method involves easy calculations and is reproducible and accurate.

Body Water↗
PubMed1978

Severe chest trauma. Morbidity implication.

Patients who sustain fracture of either the first or second rib have severe injuries usually involving multiple systems. In comparing 71 patients with first rib fractures and 49 patients with second rib fractures, we found morbidity and mortality to be similar. A multidisciplinary approach to management of these patients is described and vigorous diagnostic and therapeutic measures are warranted to promptly determine the extent of injury and minimize the frequency of missed diagnosis.

Abdominal Injuries↗
PubMed1978

Prevention of complications from prolonged tracheal intubation.

Eight commercially available soft cuff endotracheal tubes were studied to determine the relationship between inflation pressure distention of the cuff. Although the balloon cuff may be easily distensible in open air, when confined within the trachea small increments in the inflation volume may produce high pressures. This means that continuous external control of cuff pressure is required to prevent ischemia of the tracheal wall. Major tracheal complications in a busy ICU were examined before and after the introduction of a controlled pressure tube. Control of intratracheal cuff pressures decreased major tracheal complications tenfold and eliminated complications specifically related to the cuff.

Dilatation, Pathologic↗
PubMed1977

Incidence and outcome of posttraumatic respiratory failure.

From 1972 through 1975, a total of 6,196 patients were admitted to San Francisco General Hospital Trauma Service, of whom 908 required admission to an intensive care unit and 390 required mechanical ventilation. Duration of mechanical ventilation was one week or less for 76%, two weeks or less for 90%, and four weeks or less for 97%. Survival in patients ventilated seven days or less was 64%, in patients ventilated 8 to 14 days it was 55%, and in patients ventilated 15 to 30 days it was 55%. The mortality for ventilated patients aged 20 to 49 years was 23% while for ventilated patients older than age 60 it was 53%. The average age of ventilated patients was 43. Use of controlled-pressure soft-cuff endotracheal tubes has eliminated tracheal-esophageal fistula and tracheal stenosis as causes of morbidity and mortality. Appropriate ventilator alarms have minimized fatalities due to mechanical equipment failure. Complications related to positive pressure ventilation, such as pneumothorax and subcutaneous emphysema, still occur in 12% to 18% of patients. In our patients who survived the acute respiratory distress syndrome, recovery of lung function was universal, and permanent disability was less than 1%.

Adolescent↗