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Biomedical subjects

E Hew

Publications and source records attributed to E Hew.

12 recordsLinked to original sources
PubMed1990

Oxygen transport and oxygen consumption in critically ill patients.

We performed a prospective study in 28 critically ill patients to document variations in oxygen consumption and oxygen transport that occur spontaneously, without any experimental interventions designed to change DO2. Each study consisted of from three to five sets of measurements, including thermal dilution cardiac output and blood gases. The interval between any two measurements ranged from 20 to 60 minutes. It was concluded that changes in VO2 and DO2 can occur spontaneously in patients with normal lactates, even when there are no experimental interventions. These spontaneous changes in VO2 and DO2 make it extremely difficult to interpret studies that demonstrate that VO2 is transport-limited. The changes in DO2 can likely be explained by changes in oxygen demand.

Adult↗
PubMed1990

Taking issue.

Explore the source record for details and available documents.

Anesthesia, Obstetrical↗
PubMed1989

Epidural anaesthesia and thrombocytopenia.

A case is presented of a mother with unanticipated profound thrombocytopenia who received a continuous epidural anaesthetic for labour. No neurological sequelae or excessive bleeding occurred. It is clear, after a review of the literature, that more information is needed to define the lower limits of platelet count at which it is safe to proceed with epidural anaesthesia.

Adult↗
PubMed1987

A comparison of two types of epidural catheters.

The purpose of this study was to compare two epidural catheters--the Portex epidural catheter and Vas-Cath catheter. One hundred and fifty patients in labour who received epidural anaesthesia were selected and either one or the other catheter was used, based on random assignment. Ease of insertion, maintenance and removal of the catheter were assessed, as was the incidence of blood return and paraesthesiae during epidural catheter insertion. There were no significant differences between the catheters as far as insertion, maintenance and removal were concerned. However, the incidence of paresthesiae was 44 per cent with the Portex and 24 per cent with Vas-Cath catheters (p less than 0.008). The incidence of blood vessel trauma was 12 per cent with the Portex and 6.7 per cent with the Vas-Cath catheter (p = NS). Choice of epidural catheter is a factor to be considered in minimizing the incidence of blood vessel trauma or paresthesiae.

Anesthesia, Epidural↗
PubMed1987

A comparison of nalbuphine and meperidine in treatment of postoperative pain.

The analgesic efficacy and side effect profile of nalbuphine 20 mg IV and of nalbuphine 40 mg IV were compared to those of meperidine 75 mg IM in the immediate postoperative period. Pain intensity, pain relief, additional analgesic requirements and the overall acceptability of the treatment were recorded for 150 patients. No significant differences were found between the groups for any of the efficacy variables. Peak analgesic effects occurred at 15 minutes in both nalbuphine groups and at 30 minutes in the meperidine group. The mean time to additional analgesic medication was approximately 207 minutes in each group. The incidence of nausea and vomiting with meperidine was 22 per cent (95 per cent confidence interval 10 to 34 per cent) and with nalbuphine 20 mg the incidence was two per cent (95%CI -2 to 6 per cent). This difference was significant (p less than 0.01). The difference between nalbuphine 40 mg (10 per cent, 95%CI 1 to 19 per cent) and meperidine, was not considered statistically significant (p = 0.17). The analgesic efficacy of nalbuphine 20 mg was indistinguishable from that of nalbuphine 40 mg and from that of meperidine 75 mg. The significantly lower incidence of nausea and vomiting with nalbuphine is a major advantage for a recovery room analgesic.

Abdomen↗
PubMed1985

Clarification of the effects of changes in P50 on oxygen transport.

In summary, a shift to the right in the O2-Hb curve in patients with anemia and decreased cardiac output and normal PaO2 will increase PvO2. This shift is mediated through increases in red cell 2,3-DPG. The stimulus for the increase in 2,3-DPG is most likely due to the decrease in SvO2. In hypoxemia caused by a decreased PAO2 (altitude), an increase in P50 may have no effect on PvO2 and in fact if the PaO2 is low enough, a left shift may increase the PvO2. Animals and man most successful at adapting to high altitudes reflect this fundamental physiological effect and have a left-shifted curve. This decrease in P50 is probably related to an intrinsic property of the hemoglobin and not to changes in 2,3-DPG. In hypoxemia caused by shunt, an increase in P50 increase the PvO2 regardless of the PaO2. Patients with congenital cyanotic heart disease have an increased P50 mediated through an increase in 2,3-DPG.

Altitude↗
PubMed1978

Lactic acidosis presenting as acute respiratory failure.

Two patients with chronic obstructive pulmonary disease and chronic respiratory failure who developed acute lactic acidosis are described. The initial arterial blood gas values in both patients had the pattern of acute respiratory failure with no metabolic disturbance. It was the calculation of the "anion gap" that provided the clue to the presence of metabolic acidosis, which was then confirmed with the measurement of serum lactate. We emphasize that complete laboratory data and clinical information may be essential for accurate diagnosis and understanding of mixed acid-base disturbances and, hence, for initiation of appropriate treatment.

Acidosis↗