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Biomedical subjects

E G Pavlin

Publications and source records attributed to E G Pavlin.

At least 37 records · Page 2Linked to original sources
PubMed1987

Incidence and effect of hypothermia in seriously injured patients.

Hypothermia is a well recognized consequence of severe injury, even in temperate climates, and the physiologic consequences of hypothermia are known to be detrimental. To analyze the frequency and risk factors for hypothermia and its effect on patient outcome, we prospectively studied 94 intubated injured patients at a regional trauma center during a 16-month period. Esophageal temperature probes were placed in the field or ER and core temperatures (T) were followed for 24 hours or until rewarming. Patients were designated as normothermic (greater than 36 degrees C), mildly hypothermic (34 degrees C-36 degrees C) or severely hypothermic (less than 34 degrees C) based on initial T. The risk factors for hypothermia evaluated included age, severity and location of injuries, blood alcohol level, blood transfusion requirements, and time spent in the field, ER, or OR. The average initial T was 35 degrees C, with no seasonal variation. Injury severity and survival correlated with severe hypothermia. Normothermic patients had an average ISS of 28 with a 78% survival. Severely hypothermic patients had an average ISS of 36 with a 41% survival (p less than 0.05). Patient age strongly correlated with outcome although there was no relationship between age and initial temperature. Sixty-two per cent of patients tested were positive for blood alcohol, and one half were legally intoxicated (BAC greater than 100 mg%). However, no consistent correlation was found between alcohol intoxication and initial temperature or patient survival. Blood transfusion requirements paralleled injury severity and patients receiving greater than 10 unit transfusions had significantly lower core temperature (p less than 0.05). The average temperature change was positive in the ER, OR, and ICU with time to rewarming correlating with the aggressiveness of warming measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Effect of meperidine on oxygen consumption, carbon dioxide production, and respiratory gas exchange in postanesthesia shivering.

Meperidine has been used to suppress postanesthesia shivering. However, its efficacy to date has only been assessed by observation of visible shivering. We measured the effect of meperidine on oxygen consumption (VO2), carbon dioxide production (VCO2) and pulmonary gas exchange in 14 otherwise healthy patients shivering after general anesthesia. Meperidine successfully suppressed visible shivering in all patients and was associated with significant decreases in VO2, and VCO2 and minute ventilation (VE) but not with return to basal levels. Arterial PCO2 levels remained unchanged at normal, whereas significant improvements occurred in pH and bicarbonate levels. Meperidine is an effective method of reducing the elevated metabolic demand of shivering.

Acidosis↗
PubMed1983

Utilization of blood recycling in nonelective surgery.

Intraoperative infusion of autologous shed blood is efficacious in elective vascular, cardiac, and orthopedic surgery. Blood recycling has also been advocated for emergency and trauma surgery. We examined 33 candidates for autotransfusion during emergency surgery. Autologous blood accounted for only 11% of the total blood replaced. Only 25 of the patients survived long enough to permit reinfusion. Because of rapid hemostasis, nine of the remaining patients (36%) received less than the 2 units necessary to be cost-effective. No evidence was found for septicemia or coagulopathy caused by autotransfusion. We concluded that, as currently applied, recycling of shed blood during emergency surgery is of value in a limited group of patients. The collection and storage of heparinized shed blood during the preoperative and early intraoperative periods, with later processing and reinfusion in selected patients, may expand its applicability.

Adult↗
PubMed1982

Studies in transtracheal ventilation catheters.

A study was undertaken to assess the applicability of transtracheal ventilation in the instance of total upper airway obstruction. The effect of transtracheal jet ventilation through a variety of inflow catheters in the dog was studied. Arterial blood gas values, intratracheal pressure and minute ventilation were compared. Deflation of the airway through an array of outflow needles was independently assessed. Hypercapnia, decreased minute ventilation, and prolonged inspiratory and expiratory durations impaired use of the smallest catheters. A dual-lumen needle, to provide exclusive respiratory access and support was then designed based on the preliminary data. Prolonged transtracheal jet ventilation with a totally obstructed upper airway was successfully conducted in a live canine subject. A review of the literature is presented.

Airway Obstruction↗
PubMed1981

Transfer of pethidine to CSF following intravenous administration.

To help delineate the contributions to analgesia evoked by central and spinal opiate receptors, pethidine was administered intravenously to dogs by bolus followed by infusion. Plasma and cerebrospinal fluid were sampled and assayed for pethidine. Cerebrospinal fluid concentrations followed a similar time course to plasma but with lower concentrations. The average cerebrospinal fluid:plasma ratio was 0.4 and resembled the fraction of unbound pethidine in plasma. It was concluded that cerebrospinal fluid concentrations after intravenous administration were so low that spinal action would be unlikely.

Animals↗
PubMed1981

Effects of positive end-expiratory pressure on intracranial pressure in dogs with intracranial hypertension.

Positive end-expiratory pressure (PEEP) is used to improve oxygenation in patients with the adult respiratory distress syndrome. Nevertheless, this treatment may increase intracranial pressure (ICP) and be detrimental to certain neurosurgical patients. This clinical situation was simulated by administering PEEP to dogs with normal and elevated ICP. Increases in PEEP increased ICP in all animals. However, the presence of intracranial hypertension diminished the increase in ICP seen at a given level of PEEP. Cerebral perfusion pressure also fell less in the presence of intracranial hypertension than it did in the absence, although in the former situation cerebral perfusion pressure was at the lower limits of the range of cerebral autoregulation. These findings suggest that PEEP is no more detrimental to patients with elevated ICP than it is to patients whose ICP is normal, assuming that their cerebral autoregulation is not impaired.

Animals↗
PubMed1978

Effect of positive end-expiratory pressure on intracranial pressure in dogs.

Application of positive end-expiratory pressure to dogs with noncardiogenic pulmonary edema increased intracranial pressure (measured as cerebrospinal fluid pressure) and decreased cerebral perfusion pressure. The magnitude of these changes depended on the amount of end-expiratory pressure applied and the lung compliance.

Animals↗
PubMed1975

Distribution of H+ and HCO3 minus between CSF and blood during metabolic acidosis in dogs.

To determine whether the regulation of brain extracellular fluid acid-base balance is by active ion transport or passive distribution, changes in cisternal and lumbar cerebrospinal fluid (CSF) (H+) and (HCO3 minus) were assessed in five dogs with normal acid-base status and in six dogs during metabolic acidosis. Both groups were mechanically ventilated to maintain a constant PaCO2. The pH, PCO2, (HCO3 minus), and (lactate) in CSF and arterial plasma and the CSF/plasma DC potential difference were determined at intervals, and the electrochemical potential differnces (mu) for H+ and HCO3 minus were calculated. Following control measurements at pHa equal to 7.40, metabolic acidosis was induced by infusion of 0.6 N HCl. Measurements were made 0, 3, 4.5, and 6 h thereafter and at 0, 3, and 6 h in the control series. A steady state for ion distribution was reached by 4.5 h. In the control series at 6 h the values of mu for H+ and HCO3 minus were within minus 0.2 and +0.5 mV of initial values at the cistern and +0.1 and +0.9 mV at the lumbar site. During metabolic acidosis, the 6-h values at the cistern returned to 0.0 and +0.7 mV of control for muH+ and muHCO3 minus while lumbar values returned to +0.5 and minus 0.4 mV. The closeness of these 6-h values of mu to control is compatible with passive distribution of H+ and HCO3 minus between CSF and blood.

Acid-Base Equilibrium↗
PubMed1975

Distribution of H+ and HCO3 minus between CSF and blood during metabolic alkalosis in dogs.

In anesthetized, paralyzed dogs ventilated to maintain a normal PaCO2, metabolic alkalosis was induced and held constant over 6 h by infusion of sodium bicarbonate. Determination of pH, PCO2, (HCO3 minus), and (lactate) in cisternal and lumbar cerebrospinal fluid (CSF) and in arterial plasma together with measurement of the CSF/plasma DC potential differences permitted calculation of the electrochemical potential difference (mu) for H+ and HCO3 minus; measurements were made prior to induction of metabolic alkalosis at pHa equal to 7.40, as soon after induction as stable arterial values were achieved and 3, 4.5, and 6 h thereafter. A steady state for ion distribution was reached by 4.5 h. Values of mu for H+ and HCO3 minus returned to +0.1 and +0.9 mV of control at 6 h for cisternal CSF and +0.6 and minus 0.4 mV for lumbar CSF. This return of muH+ and muHCO3 minus close to control in the steady state is compatible with passive distribution of these ions between brain extracellular fluid and blood.

Acid-Base Equilibrium↗
PubMed1975

Distribution of H+ and HCO3 minus between CSF and blood during respiratory acidosis in dogs.

To evaluate the regulation of (H+) and (HCO3 minus) in brain extracellular fluid during respiratory acidosis, the changes in cisternal and lumbar CSF acid-base state were assessed in six anteshetized, paralyzed, mechanically ventilated dogs rendered hypercapnic by increase in FIco2. Arterial (HCO3 minus) was held constant. The electrochemical potential difference (mu) between CSF and blood for H+ and HCO3 minus was calculated from values for (H+) and (HCO3 minus) in CSF and arterial plasma and the simultaneously measured CSF/plasma DC potential difference. Measurements were made at pHa equal to 7.40, after stable arterial values of pHa of about 7.2 were attained and 3, 4.5, and 6 h thereafter. A steady state for ion distribution was attained by 4.5 h. Values of mu for H+ and HCO3 minus at 6 h had returned to +0.7 and minus 0.7 mV of control for cisternal CSF and +1.3 and minus 0.6 mV of control for lumbar CSF. The attainment of steady-state values for mu close to control is comparable with passive distribution of these ions between CSF and blood.

Acid-Base Equilibrium↗
PubMed1975

Distribution of H+ and HCO3 minus between CSF and blood during respiratory alkalosis in dogs.

Anesthetized, paralyzed dogs after a control period at normal pHa were hyperventilated to produce a hypocapnic alkalosis. The pH, PCO2, (HCO3 minus), and (lactate) in cisternal and lumbar CSF and arterial blood were determined at normal conditions (control) shortly after induction of respiratory alkalosis (time 0) and 3, 4.5, and 6 h thereafter. These values along with measurements of the CSF/plasma DC potential (E) allowed calculations of the electrochemical potential difference (mu) between CSF and blood for H+ and HCO3 minus. After 6 h of hypocapnic alkalosis, muH+ and muHCO3 minus had returned to minus 0.7 and minus 1.0 mV of control at the cistern and to minus 1.0 and +0.4 mV of control for lumbar CSF. This return of mu is compatible with a passive distribution of these ions though active ion regulation is not ruled out. Assuming passive distribution, differences in deltaE/DELTApHa between metabolic and respiratory acid-base changes determined the extent of CSF pH homeostasis during compensated acid-base derangements.

Acid-Base Equilibrium↗