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Biomedical subjects

P Hutton

Publications and source records attributed to P Hutton.

At least 19 recordsLinked to original sources
PubMed1997

A comparison of eltanolone and propofol anaesthesia for minor gynaecological surgery.

We have used eltanolone and propofol to induce anaesthesia and by intermittent injection to supplement nitrous oxide during maintenance in 67 patients undergoing minor gynaecological surgery. This study was a controlled randomized phase III with two parallel groups and a blinded assessment of post-operative recovery. Complications during induction and maintenance were few. Urticaria occurred in two patients given eltanolone and in none of those given propofol. Time to orientation and time to eye opening were significantly shorter in the propofol group (P < 0.001). Systolic and diastolic blood pressure decreased in both groups but the decrease was significantly greater in the propofol group (P < 0.005 systolic blood pressure; P < 0.001 diastolic blood pressure). Heart rate decreased significantly in the propofol group (P < 0.002). We conclude that eltanolone anaesthesia is associated with a greater haemodynamic stability than propofol anaesthesia but that early recovery occurs more slowly.

Adult↗
PubMed1997

Prevention of remote organ injury in cardiopulmonary bypass: the impact of flow generation technique.

The purpose of this study was to investigate the effects of 3 different types of flow generation for cardiopulmonary bypass on gastrointestinal permeability and on neutrophil expression of CD11b, a surface marker of neutrophil activation. Fourteen patients undergoing elective coronary revascularization were selected randomly to receive 1 of the 3 flow generation techniques (roller, pulsatile, or centrifugal). Intestinal permeability was assessed by the fraction of an oral dose of 51chromium-ethylenediaminetetraacetate (51Cr-EDTA) recovered in the urine over 24 h. Neutrophil activation was determined by expression of CD11b markers at 6 time points. Overall, the 14 patients showed significant increases in intestinal permeability. It was not possible to demonstrate statistically significant differences among the flow generation groups; however, when compared to both roller pump groups, the centrifugal pump group showed a 3.2% reduction in intestinal permeability. There was no change in the expression of CD11b receptors throughout the time points, nor was there a relationship of CD11b markers to the flow generation technique.

Administration, Oral↗
PubMed1995

Retrograde cerebral perfusion: clinical experience in emergency and elective aortic operations.

We recently have used retrograde cerebral perfusion via the superior vena cava in association with hypothermic circulatory arrest as an adjunct to cerebral protection during aortic arch operations. Between April 1993 and March 1994, 23 patients (14 male; 9 female; median age, 64 years; age range, 25 to 76 years; 14 emergency, 9 elective) underwent operation on the ascending aorta, aortic arch, or both for acute dissection (11) or aneurysm (12). Aortic root replacement was performed in 13 patients (7 with arch replacement), ascending aortic replacement in 7 (4 with arch replacement), isolated aortic arch replacement in 2, and repair of sinus of Valsalva aneurysm in 1. Coronary artery bypass grafting was performed in 4 patients. Hypothermic circulatory arrest (15 degrees C) and retrograde cerebral perfusion were implemented in all cases (median circulatory arrest time, 21 minutes; range, 13 to 51 minutes; median retrograde cerebral perfusion time, 20 minutes; range, 12 to 50 minutes). Three hospital deaths occurred (atheromatous embolic stroke, sepsis, rupture of infrarenal aortic aneurysm). The remaining patients had no neurologic damage (median intensive therapy unit stay, 1 day; range, 1 to 5 days). Retrograde cerebral perfusion is easy to establish and safe, and may improve brain protection during hypothermic circulatory arrest.

Adult↗
PubMed1995

Use of i.m. temperature probes during cardiopulmonary bypass in humans.

I.m. temperature probes were used in humans during and after hypothermic cardiopulmonary bypass (CPB). After rewarming to apparent normothermia of the body core, we found that the temperature of the vastus lateralis muscle remained well below the nasopharyngeal temperature at the time of weaning from bypass. This reduced muscle temperature represents a considerable deficit in total body heat which may account for a large proportion of the afterdrop in temperature which occurs in the postoperative period. There was no morbidity associated with the use of the i.m. probes which could be incorporated into standard clinical practice.

Adult↗
PubMed1995

Manual compared with target-controlled infusion of propofol.

We studied 160 ASA I-II patients, anaesthetized with propofol by infusion, using either a manually controlled or target-controlled infusion system. Patients were anaesthetized by eight consultant anaesthetists who had little or no previous experience of the use of propofol by infusion. In addition to propofol, patients received temazepam premedication, a single dose of fentanyl and 67% nitrous oxide in oxygen. Each consultant anaesthetized 10 patients in sequential fashion with each system. Use of the target-controlled infusion resulted in more rapid induction of anaesthesia and allowed earlier insertion of a laryngeal mask airway. There was a tendency towards less movement in response to the initial surgical stimulus and significantly less movement during the remainder of surgery. Significantly more propofol was administered during both induction and maintenance of anaesthesia with the target-controlled system. This was associated with significantly increased end-tidal carbon dioxide measurements during the middle period of maintenance only, but recovery from anaesthesia was not significantly prolonged in the target-controlled group. With the exception of a clinically insignificant difference in heart rate, haemodynamic variables were similar in the two groups. Six of the eight anaesthetists found the target-controlled system easier to use, and seven would use the target-controlled system in preference to a manually controlled infusion. Anaesthetists without prior experience of propofol infusion anaesthesia quickly became familiar with both manual and target-controlled techniques, and expressed a clear preference for the target-controlled system.

Adolescent↗
PubMed1994

Application of flow cytometric methods for the routine detection of Cryptosporidium and Giardia in water.

Cryptosporidium and Giardia are common causes of waterborne disease. The currently used methods of detecting these organisms in water rely on filtration capture, immunofluorescence labelling, and epifluorescence microscopy. These methods are inefficient, labour intensive, and require a highly skilled microscopist. We describe an alternative technique using flocculation concentration, followed by flow cytometry with fluorescence activated cell sorting. Environmental samples were analysed, and protozoan-like particles were sorted and collected before confirmation with epifluorescence microscopy. The technique was found to be significantly more sensitive and considerably faster than the conventional methods.

Animals↗
PubMed1994

Recognition of cardiogenic artifact in pediatric capnograms.

The capnograph is in regular use as a respiratory monitor. From measurements of its trace, calculations of breathing rate and end-tidal carbon dioxide can be made. Unfortunately, the reliability of these calculations depends on the quality of the signal. In the case of cardiogenic oscillations, the averaged results may be grossly inaccurate and, therefore, misleading. This paper describes a method for detecting such cardiogenic oscillations and removing their effect from the final results of capnogram analysis. The algorithm used resulted in a sensitivity of 99.6% and a specificity of 99.2%, when compared with manual scoring. The criteria could easily be incorporated into equipment software and are a step in the direction of "intelligent" monitoring.

Algorithms↗
PubMed1994

Selective decontamination of the digestive tract reduces gram-negative pulmonary colonization but not systemic endotoxemia in patients undergoing elective liver transplantation.

OBJECTIVE: To examine the effect of selective antibiotic decontamination of the digestive tract in patients undergoing elective orthotopic liver transplantation. DESIGN: Prospective, randomized, concurrent allocation to either selective decontamination or standard antibiotic prophylaxis. SETTING: Operating theater and intensive care unit at a tertiary referral, university teaching hospital. PATIENTS: Fifty-nine adult patients were recruited into the study and underwent liver transplantation. INTERVENTIONS: Thirty-two patients were randomized to standard treatment (control group) and 27 patients were randomized to receive selective decontamination. After early deaths and exclusions, 31 controls and 21 decontamination patients were available for analysis. MEASUREMENTS AND MAIN RESULTS: Portal and systemic endotoxemia, colonization and infection rates, severity of illness (organ system failures, Acute Physiology and Chronic Health Evaluation II score, Therapeutic Intervention Scoring System score), antibiotic costs, and hospital survival rates were measured. Selective decontamination significantly reduced pulmonary infections and enteric, aerobic, and Gram-negative bacillary colonization without facilitating the emergence of resistant organisms, but selective decontamination had no effect on endotoxemia or the development of organ system failures. The financial costs of the selective decontamination regimen outweighed the advantages gained from an associated reduction in antibiotic usage. CONCLUSION: The failure of selective decontamination to enhance survival rates in many studies of the regimen in critically ill patients may, in part, be related to the inability of selective decontamination to abolish endotoxemia.

Adult↗
PubMed1994

Clinical evaluation of sodium ion selective field effect transistors for whole blood assay.

Sodium ion selective field effect transistors (ISFETs) were evaluated for their performance in measurement of sodium ions in whole blood for 'near patient' analysis in operating theatres and intensive care units. Performance was evaluated in comparison with a standard clinical laboratory sodium/potassium ion analyser (Radiometer KNA1) and with sodium and potassium assays using flame photometry on the plasma from each whole blood specimen. The imprecisions (coefficients of variation) of three ISFETs for sodium ion assay were 1.08, 1.56 and 1.10%, respectively. Robust bivariate linear regression (reweighted least squares preceded by least median of squares) of the ISFET versus KNA1 sodium ion activity yielded a regression coefficient of 1.08 and an intercept of -18.2 mM. The influence of potassium, protein and lipid on the measurement of sodium ions by both ISFETs and the KNA1 was assessed using robust multiple regression (also based on reweighted least squares preceded by least median of squares). In the regression versus flame photometry, protein was found to be more influential for the KNA1 (glass sodium ion selective electrode) than for the ISFET. Potassium had no influence on assays using the ISFET, but had a weak negative influence on assays using the KNA1. Two ISFETs lasted for more than 200 assays each demonstrating their robustness in the assay of whole blood.

Blood Chemical Analysis↗
PubMed1993

Nasal capnography in children: automated analysis provides a measure of obstruction during sleep.

A detailed analysis was made of nasal capnograms obtained from sleeping children with differing degrees of sleep-induced respiratory obstruction, the severe form being known as obstructive sleep apnoea. Clinical observations of these children were compared with analyses of nasal capnography data. During periods when the degree of obstruction was consistent throughout the first hour of sleep, the means and coefficients of variation of several parameters, derived from the capnograms were calculated. The coefficients of variation showed a close relationship to the degree of obstruction. In comparison, measures of end-tidal carbon dioxide concentration proved to be a very insensitive index of the degree of obstruction. The conclusion is that the usefulness of nasal capnography in predicting and grading obstruction can easily be extended by the use of statistical measures of dispersion and that this concept warrants further work.

Airway Obstruction↗
PubMed1992

Hypoxia in sleeping children: overnight studies can be reduced to 4 hours without loss of clinical significance.

Twelve recordings of overnight pulse oximetry representing a range of severity of obstructive sleep disturbance were evaluated by 7 experienced clinicians. Each recording was then scored by counting the number of minutes in each hour affected at any time by a fall in saturation to below 90%. Comparison of the clinical evaluation and the overall scores gave a clear level of 5 minutes per hour at and above which all the assessors agreed that the charts had clinically important desaturation. Overnight pulse oximetry was then performed on 25 children aged between 12 months and 10 years about to undergo adenotonsillectomy. The charts were scored by the method above with a score of 5 or more indicating a positive result for hypoxic episodes. The scores for shortened analysis periods of 1, 2, 3 and 4 hours duration were compared with the overall score and no cases which were negative, up to and including 4 hours, became positive in the overall result. Thus recording pulse oximetry for 4 hours provides sufficiently accurate information for clinical purposes.

Child↗
PubMed1991

Comparison of invasive and non-invasive measurements of continuous arterial pressure using the Finapres.

A comparison was made of arterial pressures measured invasively from a radial arterial cannula and non-invasively from the middle finger using the 2300 Finapres (Ohmeda) during induction and maintenance of anaesthesia. Digital outputs of both pressures were captured directly onto computer hard disk; data recorded during flushing of the arterial line were excluded from analysis. We studied 53 patients undergoing cardiac, major vascular and neurosurgical procedures; 17705 comparisons of systolic, diastolic and mean pressure were analysed. Overall correlations between Finapres and invasive pressures were poor (r = 0.82, 0.68 and 0.78 for systolic, diastolic and mean pressures, respectively). The Finapres exhibited a high level of accuracy and precision in some recordings. However, patient data sets showed marked variability in average pressure differences (invasive minus Finapres) when examined individually or grouped by operation type. Unexplained variations in pressure difference with time and absolute pressure were observed also. Whilst providing useful beat-to-beat information on arterial pressure trends, the Finapres cannot be recommended as a universal substitute for invasive arterial pressure monitoring.

Adult↗
PubMed1991

Flumazenil in intensive care. The duration of arousal after an assessment dose.

The effect of an assessment dose of the benzodiazepine antagonist flumazenil was studied in 20 patients in an intensive care unit. The patients had been sedated with alfentanil and midazolam, and were ready to be weaned from mechanical ventilation. In 10 patients flumazenil was titrated just to produce full arousal whilst the midazolam infusion was continued; flumazenil administration was repeated one hour later after the infusion of midazolam had been stopped. In another 10 patients, flumazenil was administered only once, coinciding with the cessation of sedation. The duration of full arousal in both groups was less than 15 minutes in 75% of patients given a single dose of flumazenil (median dose 0.4 mg) although some effect persisted for up to 60 minutes. The cardiovascular effects of arousal were transient and probably not clinically significant. A brief duration of action is advantageous if the patient is found still to require sedation.

Adult↗