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Biomedical subjects

C Weissman

Publications and source records attributed to C Weissman.

126 records · Page 7Linked to original sources
PubMed1983

Morphine and postoperative rewarming in critically ill patients.

Morphine sulfate (MSO4) has been demonstrated to attenuate the stress response. MSO4 might be useful in minimizing the stress associated with the perioperative period, particularly that due to awakening from anesthesia and rewarming. Two groups of critically ill patients who developed hypothermia (35.8 degrees C) during a surgical procedure were studied. The control group was observed during routine medical management. Group II received 1 or 4 mg/kg MSO4 followed by an infusion of 0.2 or 0.5 mg/kg/hr. During the postoperative rewarming period the control group patients demonstrated a major increase in metabolic demand and myocardial work. In group II patients the infusion of MSO4 resulted in a lower metabolic rate. This was associated with a significantly longer rewarming time and a significant reduction in shivering, heat loss, heart rate, mean arterial pressure, and rate-pressure product. Infusion of MSO4 in critically ill patients during the perioperative period suppressed metabolic demands and myocardial work while preserving cardiovascular function.

Aged↗
PubMed1983

Amino acids and respiration.

Parenteral nutrition containing glucose and amino acids may stimulate respiration. To ascertain the effects of these solutions on respiration, eight normal subjects received an infusion of 5% dextrose (100 mL/h) for 7 days followed by an infusion of 3.5% amino acids (125 mL/h) for 24 hours. Minute ventilation (VE), tidal volume, mean inspiratory flow (VT/VI), oxygen consumption, and carbon dioxide production were significantly depressed after 7 days of 5% dextrose infusion. Ventilation and metabolic rate increased within 4 hours after initiation of the amino acid infusion and returned to normal 24 hours after the infusion. The effects of the amino acids on (VE) was secondary to an increase in (VT/VI), which is an indicator of neuromuscular ventilatory drive. Thus, within 4 hours amino acids will restore depressed metabolic rate, minute ventilation, and ventilatory drive after prolonged infusion of 5% dextrose.

Adult↗
PubMed1983

Physiologic requirements during rewarming: suppression of the shivering response.

Intraoperative hypothermia has become a common occurrence. Postoperative rewarming often is accompanied by shivering and results in increased metabolic and circulatory demands. We examined the metabolic, hemodynamic, and biochemical variables in 2 groups of hypothermic (greater than 35.8 degrees C) patients requiring mechanical ventilation after a major operation. One was observed during routine medical management whereas the other group received 40 mg of metocurine iodide and then observed during routine medical management. All patients were allowed to rewarm passively. O2 consumption (VO2, ml/min, STPD), CO2 production (VCO2, ml/min, STPD) and respiratory quotient (RQ) measurements were made every 15 min using a Beckman Metabolic Measurement Cart. Esophageal temperature, arterial blood pressure, heart rate (HR), rate pressure product, CVP, arterial blood gases, serum lactate concentration, and duration of shivering also were recorded. Suppression of the shivering by metocurine increased rewarming time significantly and decreased VCO2, VO2, HR, rate pressure product, mean arterial pressure (MAP), and the O2 cost of rewarming. Thus, the elimination of shivering during postoperative rewarming is associated with a decrease in caloric, metabolic demands and myocardial work (as assessed by the rate pressure product) while rewarming time is prolonged. In the postoperative, hypothermic, critically ill patient, suppression of the shivering response in selected patients may be indicated.

Adult↗
PubMed1983

Nutrients and ventilation.

Nutritional support of the patient with respiratory failure may play a key role in recovery. Nutritional intake not only indirectly influences lung function by altering body composition and most defense mechanisms but interacts directly with respiratory function in a variety of ways. This review will focus on 2 such interactions; the effect of glucose on CO2 production and the effect of protein on ventilatory drive. Glucose administration results in increases in CO2 production via 2 mechanisms; 1) a thermogenic effect and 2) an increase in the respiratory quotient (RQ). In the hypermetabolic, acutely ill patient, both the thermogenic effect and the rise in the RQ contribute to the rise in CO2 production. In the malnourished patient, a rise in the RQ is the primary mechanism for the increase. In either case, the increased need for CO2 elimination results in an increase in ventilatory demand which may precipitate respiratory distress in a patient with previously compromised pulmonary function. Infusions of amino acids, either alone or as a part of a complete nutritional support regimen, results in an enhanced ventilatory response to CO2. This seems to be a result of the thermogenic effect of protein and an increase in the ratio of the plasma concentration of the large amino acids to tryptophan. We postulate that brain uptake of tryptophan which is a precursor to serotonin (a known respiratory inhibitor) is reduced by the presence of increased amounts of the large neutral amino acids that compete with tryptophan for transport across the blood brain barrier, thereby resulting in respiratory stimulation.

Amino Acids↗
PubMed1983

Nutritional support of the acutely ill patient.

Administration of nutritional support in acutely ill patients can be seen as a balance between the need to provide nutrients and the known complications associated with infusions of each of the three major nutrients--glucose, fat, and protein. It is prudent to maintain calorie intake within reasonable limits. If facilities for measurements of O2 consumption and hence metabolic rate are available, these should be utilized. Otherwise, metabolic rate should be estimated. In patients who are in satisfactory nutritional condition and who are being nourished to preserve lean body mass, diets designed to maintain body cell mass should be utilized. Practically speaking this means an energy intake of 1.0 to 1.2 times the daily energy expenditure and an N intake of 200 to 300 mg/kg/day. In patients where the goal is restoration of lean body tissue, a nutritional regimen designed to achieve a positive calorie and N balance should be used. This generally means an energy intake of 1.4 to 1.6 times the energy expenditure, with a N intake of 250 to 400 mg/kg/day. The nonprotein calories are administered as 50% glucose and 50% fat. These recommendations are based on studies performed to data. The area of nutritional support of the acutely ill patient is under extensive investigation. It is likely that as more data are collected, these guidelines will be revised.

Acute Disease↗
PubMed1982

A systematic method for validation of gas exchange measurements.

The measurement of gas exchange is useful, but thus far, has not been practical during the mechanical ventilation of critically ill patients. To validate two new commercial instruments, (Siemens-Elema Servo Ventilator 900B, Beckman Metabolic Cart), the authors constructed a lung model into which they delivered CO2 and N2 at precise rates to simulate Co2 production (Vco2) and O2 consumption (Vos). The model consists of 13.5-1 gas jar with an attached one liter anesthesia bag. The lung model was ventilated at present tidal volumes and frequencies. The authors also compared the measured respiratory quotient (RQ) with the known RQ of burning methanol (RQ = 0.67) in the jar. When the model was ventilated with levels of tidal volume and gas exchange applicable to adults, both instruments measured V02 within 5 to 13% of predicted values. Varying the FI02 did not significantly affect this accuracy. At tidal volumes below 350 ml, the difference increased between predicted VCO2 and measured VCO2. The difference between measured vs. the actual RQ of methanol was 5 and 1.5% in the Siemens-Elema and Beckman Systems, respectively.

Carbon Dioxide↗
PubMed1982

Massive perioperative polyuria.

A 25-year-old man with a spinal cord transection secondary to a gunshot wound underwent surgical repair of a perforated prepyloric ulcer on the eighth hospital day. He received 68 liters and excreted 43 liters of intravenous fluid during the perioperative period. Causes of this massive polyuria during and after the second operation are unknown, although iatrogenically induced glycosuria and natriuresis may have contributed to its severity. The problems and their management are discussed.

Adult↗
PubMed1982

Effect of posture on the ventilatory response to CO2.

The effect of sitting and supine posture on breathing patterns and gas exchange during room air breathing and administration of 2 and 4% CO2 was studied in nine normal subjects using a noninvasive canopy system. During air breathing minute ventilation (VE) was 21% (P less than 0.005) higher in the sitting position. Tidal volume (VT) and mean inspiratory flow (VT/TI) were also greater in the sitting position. With the administration of 4% CO2, VE was 13.9 and 20.0 1/min in the supine and seated position, respectively. The relationship between VE and VT was the same in both cases. For any given level of VE, VT/TI was higher in the seated position. No difference in response to CO2 as measured by delta VE/delta PaCO2 and (delta VT/TI)/delta PaCO2 was observed. However, arterial PCO2 was lower both in the resting and stimulated states when sitting.

Adolescent↗
PubMed1981

Group B streptococcal pharyngitis in the compromised adult: therapeutic considerations.

Group B streptococci (GBS) have been infrequently recognized as a cause of pharyngitis. We report three cases of GBS pharyngitis in patients with underlying diseases, two of whom were treated with and responded incompletely to oral beta-lactam antibiotics. The susceptibility of 20 clinical isolates of GBS was tested by a broth dilution method to six antibiotics which could conceivably be used in the therapy of GBS pharyngitis. Penicillin G, clindamycin, and erythromycin were most active with mean minimal inhibitory concentrations (MIC) of 0.06 μg/ml or less. Rifampin and cefaclor were least active with mean MICs of 0.71 ug/ml or more. Ampicillin was intermediate in its activity. Therapy traditionally used for Group A streptococcal (GAS) pharyngitis may, at times, be suboptimal for GBS pharyngitis in compromised patients. This may be due to higher minimal bactericidal concentrations (MBC) of GBS than GAS, to inadequate penetration of penicillins into pharyngeal tissues or to host factors. It is suggested that GBS can cause pharyngitis in adults, particularly the compromised patient, and that in cases where there is a poor response to penicillin or ampicillin therapy, alternative drugs (erythromycin or clindamycin) may be used.

Adolescent↗
PubMedDate not supplied

General versus epidural anesthesia for femoral-popliteal bypass surgery.

This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in controlling cardiovascular responses during femoral-popliteal bypass surgery. Nineteen patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). The patients who underwent general anesthesia received sodium pentothal and succinylcholine for induction of anesthesia and 60% N2O, 40% O2, and 1% to 1.5% isoflurane for maintenance. Fifteen minutes before extubation, the patients received morphine sulfate 0.05 mg/kg intravenously (IV). The group that underwent epidural anesthesia received anesthesia to T-10 (through a catheter placed in the L4-5 interspace using 3% 2-chloroprocaine). Thirty minutes after the last dose, 0.05 mg/kg IV was administered. Hemodynamic variables were recorded at selected intervals during the operation and for 60 minutes in the recovery room. In the general anesthesia group, mean arterial pressure (MAP) and rate pressure product (RPP) significantly decreased (p less than 0.05) during the operation as compared with preoperative values. Following intubation and skin incision, 5 minutes after extubation, and after 60 minutes in the recovery room, MAP, heart rate (HR), and RPP were significantly greater (p less than 0.05) as compared with intraoperative periods. In the epidural anesthesia group, there were clinically important decreases in MAP and RPP after reaching T-10 and skin incision. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and after 60 minutes in the recovery room. Epidural anesthesia patients showed stable hemodynamic patterns throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Pulse contour cardiac output in surgical intensive care unit patients.

STUDY OBJECTIVE: To evaluate the ability of arterial waveform contour analysis to measure cardiac output (CO) continuously in postoperative critically ill patients. DESIGN: Thermodilution CO (TDCO) measurements were compared with simultaneous pulse contour CO (PCCO) measurements. SETTING: University hospital surgical intensive care unit. PATIENTS: 29 critically ill surgical patients with indwelling systemic arterial and pulmonary artery catheters. MEASUREMENTS AND MAIN RESULTS: TDCO measurements were compared with PCCO at 1- to 2-hour intervals. Mean TDCO was 5.75 +/- 1.79 L/min, and mean PCCO was 5.76 +/- 1.83 L/min. Analysis of the difference between TDCO and PCCO showed a bias of 0.01 +/- 0.5 L/min. Comparison of the difference between pairs of sequential TDCO measurements and the initial TDCO and subsequent PCCO measurements resulted in a correlation coefficient of 0.64. CONCLUSIONS: The PCCO method appears to be able to estimate changes in CO under the conditions tested, in which PCCO was recalibrated after each TDCO measurement. However, limitations of this method in the immediate postoperative period following aortic aneurysm surgery were identified.

Adult↗
PubMedDate not supplied

Double-blind study of glycerol vs glucose in parenteral nutrition of postsurgical insulin-treated diabetic patients.

Twenty-five insulin-treated diabetic patients were randomly assigned postoperatively to 5 days of intravenous infusions of ProcalAmine (3% amino acids, 3% glycerol, and electrolytes) or FreAmineIII + dextrose and electrolytes. The solutions were given isocalorically and isonitrogenously. Insulin was adjusted to keep glycemia at the level of 150-200 mg/dl. The ProcalAmine group by the 5th day had plasma glucose of 158 +/- 25 mg/dl and required 1.20 +/- 0.10 U/hr insulin. The FreAmine + dextrose group had plasma glucose of 169 +/- 53 mg/dl and required 2.28 +/- 0.13 U/hr. At all time points postsurgically, the ProcalAmine group required less insulin.

Adult↗
PubMedDate not supplied

In vitro evaluation of a compact metabolic measurement instrument.

The ability of the Datex Deltatrac (Sensor-Medics, Anaheim, CA) to accurately measure oxygen consumption (VO2v) and carbon dioxide production (VCO2) was examined in vitro using the carbon dioxide addition and nitrogen dilution methods. The accuracy of respiratory quotient (RQ = VCO2/VO2) measurements was assessed using methanol combustion (RQ = 0.67). Both in the canopy (blow-by) and respirator (FiO2: 0.21-0.6, PEEP: 0-12 cm H2O) modes the Deltatrac's measurements of VO2 and VCO2 were within +/- 7% of values predicted from CO2 and N2 simulations. Similar results were obtained with methanol combustion. In vitro testing revealed that the Deltatrac accurately measures VO2 and VCO2 under a variety of simulated clinical conditions.

Calorimetry↗
PubMedDate not supplied

Treatment of advanced colorectal carcinoma with AMSA.

AMSA in a dose of 120 mg/m2 iv every 4 weeks was evaluated in 26 patients with advanced measurable colorectal cancer, 13 of whom had had no prior chemotherapy. The schedule was tolerated well except by those patients who had prior irradiation or chemotherapy, in whom a dose reduction to 90 mg/m2 was required. No significant antitumor response was observed.

Adult↗
PubMedDate not supplied

The use of analgesics and sedatives in critically ill patients: physicians' orders versus medications administered.

OBJECTIVE: To examine the difference between the prescribed and actually administered dose of analgesic and sedative drugs in critically ill patients. DESIGN: Prospective survey. SETTING: University hospital surgical intensive care unit. SUBJECTS: One hundred fifty consecutive adult patients admitted to a surgical intensive care unit over a 3-month period. METHODS: Data were gathered on a daily basis. The sedation and analgesia given were compared with the daily physician orders. RESULTS: Narcotics and benzodiazepines were most commonly used. On average only 22% to 52% of the mean ordered dose of intravenous and intramuscular morphine was actually administered. Larger doses of morphine were administered to intubated patients than to nonintubated ones. Patients receiving intravenous fentanyl infusions generally were administered more than the ordered dose. The actual and prescribed doses of epidural fentanyl were well matched. Midazolam was the most frequently prescribed benzodiazepine. Like morphine, the amount administered was below the maximum ordered by the physicians. CONCLUSIONS: Physicians tended to write fairly nonspecific orders that were used by the nursing staff as very broad guidelines. A need exists to educate physicians as to what patients actually receive for sedation and analgesia and at the same time improve the dialogue between nurses and physicians as to what patients actually require.

Adolescent↗