Biomedical subjects

R W Sillett

Publications and source records attributed to R W Sillett.

At least 19 recordsLinked to original sources

PubMed1986

Distribution of carboxyhaemoglobin concentrations in smokers and non-smokers.

Carboxyhaemoglobin concentrations were measured in 3487 subjects comprising 1255 non-smokers, 1933 cigarette smokers, 193 cigar smokers (39 primary, 154 secondary), and 106 pipe smokers (30 primary, 76 secondary). In cigarette smokers the mean carboxyhaemoglobin concentration was 4.78% of the total haemoglobin and 94.7% of smokers had a concentration greater than 1.7%. Primary cigar smokers had a much lower mean carboxyhaemoglobin concentration (0.93%), and only 10.3% had concentrations greater than 1.7%. Primary pipe smokers also had a low mean carboxyhaemoglobin concentration (1.36%) and none had a concentration above 1.7%. Secondary cigar smokers had a high mean concentration (6.80%) and 97.4% had values above 1.7%; the findings in secondary pipe smokers were similar--the mean concentration was 3.39%, 94.7% having values greater than 1.7%. The lower carboxyhaemoglobin concentrations in primary pipe and cigar smokers suggest that in general they do not inhale, and the raised concentrations in cigarette smokers who change to pipes or cigars suggest that they usually continue to inhale and to absorb large amounts of carbon monoxide and other constituents of tobacco smoke.

Carboxyhemoglobin↗

PubMed1981

The inhaling habits of pipe smokers.

Carboxyhaemoglobin and plasma nicotine levels were compared in five primary and five secondary pipe (i.e. previous cigarette smoking) smokers over the course of one hour's pipe smoking. The primary pipe smokers had low pre-smoking nicotine and carboxyhaemoglobin levels with a small increase after smoking (carboxyhaemoglobin 1.1% rising to 1.26% and nicotine 7.7 nmol/litre rising to 33.9 nmol/litre). Secondary pipe smokers had a higher pre-smoking carboxyhaemoglobin and nicotine level with a significant rise during smoking (carboxyhaemoglobin 3.0% rising to 4.3%, plasma nicotine 74.3 nmol/litre rising to 215.8 nmol/litre), indicating significant inhalation and absorption of carbon monoxide and nicotine. These results indicate that primary pipe smokers, who have never smoked cigarettes, do not inhale and absorb very little nicotine. Secondary pipe smokers do not lose their habit of inhaling and absorb large amounts of nicotine and carbon monoxide. They may not share the lower health hazard of the primary pipe smoker.

Adult↗

PubMed1981

The effect of anosmia on smoking habits.

Sixteen cigarette smokers who had developed complete anosmia were questioned about their smoking habits. Four subjects increased their cigarette consumption, 8 were unchanged and 4 decreased. The development of anosmia has no consistent effect on cigarette smoking.

Adult↗

PubMed1980

The use of nicotine chewing gum as an aid to stopping smoking.

Two hundred and ten subjects entered a trial to test the use of a chewing gum containing nicotine as an aid to stopping smoking. They were divided into three groups: nicotine chewing gum, placebo chewing gum, and control. The trial was double blind between the two chewing gum groups. After 1 month the percentage of confirmed non-smokers in the nicotine gum group was 34%, in placebo chewing gum group 37% and the control group 24%. By 6 months most of the non-smokers had relapsed, but the nicotine gum group (23%) was more successful than the placebo (5% or the control group (14%).

Adolescent↗

PubMed1978

Deception among smokers.

Subjects in two different clinical trials who had been advised to stop smoking were asked if they had done so. Some 22% of subjects (11 out of 51) in the first trial and 40% (33/82) in the second trial who said they had stopped smoking were found to have raised carboxyhaemoglobin concentrations. Deception appears to be common in people trying to stop smoking.

Adolescent↗

PubMed1977

Effect of cigar smoking on carboxyhaemoglobin and plasma nicotine concentrations in primary pipe and cigar smokers and ex-cigarette smokers.

Five ex-cigarette smokers and five primary pipe and cigar smokers each smoked a large cigar. Carboxyhaemoglobin (COHb) and plasma nicotine levels were measured. In the ex-cigarette smokers mean COHb rose from 2.9% to 9.6% and plasma nicotine from 79.0 nmol/l to 281 nmol/l (12.8-45.6 ng/ml). This response was similar to that of cigarette smokers smoking cigarettes, which indicated that the subjects had inhaled and absorbed significant amounts of nicotine. In the primary pipe and cigar smokers the mean COHb rose from 0.8% to 1.0% and the plasma nicotine from 21 nmol/l to 32 nmol/l (3.4-5.2 ng/ml), indicating neither significant inhalation nor significant nicotine absorption.Since ex-cigarette smokers do not seem to lose their habit of inhaling when they change to cigars, measures aimed at persuading smokers to switch to cigars will have little effect on their health. Pipe and cigar smokers who have never smoked cigarettes do not inhale, which probably accounts for their reduced incidence of coronary heart disease and lung cancer. But they also appear not to absorb nicotine, which suggests that nicotine is absorbed largely from the lung and that the buccal mucosa is unimportant. It also raises the interesting question of why primary pipe and cigar smokers do smoke.

Adult↗

PubMed1977

Survival after cardiac arrest in hospital.

A 10-year experience of cardiac arrests in a district general hospital is reviewed. 1063 arrests in the general areas of the hospital were studied, excluding the coronary and intensive care units. In 718 (67-5%) initial resuscitation was unsuccessful; in 252 (23-7%) the patient died later in hospital, 93 patients (8-7%) were discharged alive. After discharge from hospital there was a progressive annual mortality of about 7% for the first five years, but thereafter no patient died. Significant incapacity after discharge was also unusual. The probability of successful resuscitation was greater in patients with primary cardiac disease (11-8% survival), drug overdose (22-2% survival), or undergoing anaesthesia (20-0% survival). The success-rate was significantly greater in the accident and emergency department (7-9%) than on the wards (2-1%), but this difference was due entirely to the more successful resuscitation of patients with myocardial infarction in the accident and emergency department. Within each diagnostic category the survival-rate was independent of the age of the patient. Prolonged survival after resuscitation but ending in death before discharge was unusual.

Adult↗

PubMed1977

The effects of supplementary nicotine in regular cigarette smokers.

Blood nicotine levels were measured in eight subjects over a 5-week period, while smoking normally, while smoking and chewing gum containing 2 mg nicotine, and while smoking and chewing placebo gum. Despite a small but significant rise in blood nicotine levels during the period of the nicotine gum chewing (mean 35.3 ng/ml) compared with placebo (mean 28.9 ng/ml) and control (mean 26.3 ng/ml), cigarette consumption butt lengths, filter nicotine and blood carboxyhaemoglobin levels did not change indicating that there had been no significant changes in smoking patterns. The reasons for this failure to demonstrate an effect are discussed. It is concluded that the dose of nicotine used was probably not adequate to produce an effect.

Administration, Oral↗

PubMed1976

Comparison of salmefamol with salbutamol aerosols in asthamatics.

In twelve asthmatic patients 200 mug of salmefamol and salbutamol given by metered aerosol produced a similar initial effect on FEV1, FVC and PEFR without significant effect on heart rate or blood pressure. The duration of effect of salbutamol was approximately 4 hours; there was still an appreciable effect from salmefamol at 8 hours.

Adult↗

PubMed1976

Salmefamol orally in asthmatics - two doses compared.

The responses of twelve patients with chronic asthma to salmefamol 1 mg and 2 mg, taken orally, were compared in a double-blind cross-over study. Both produced a rise of 40-50% in PEFR and FEV1. Statistically significant improvements were maintained for three to four hours, and 20% improvements for four to six hours. There was no significantly different effect on ventilatory capacity between the two doses. After the 2 mg dose there was a statistically significant fall in diastolic blood pressure at 1 and 1 1/2 hours. Four patients experienced tremor and this was the only side-effect noted. The possible reasons for failure to demonstrate a greater effect with the higher dose are discussed.

Administration, Oral↗

PubMed1975

A controlled trail of doxapram in acute respiratory failure.

The efficacy of a respiratory stimulant (doxapram) in antagonizing carbon dioxide retention associated with controlled oxygen therapy (28 per cent) in acute-on-chronic respiratory failure was assessed by a double-blind crossover trial in eight patients. PaCO2 rose in egery case during the placebo in the initial treatment period (mean increase 10 mm Hg). In those patients receiving doxapram initially PaCO2 fell in three and rose in one (mean decrease 4 mm Hg). All who has shown a rise in PaCO2 during the initial period on placebo showed a fall in the subsequent period on doxapram. In the six patients who completed the study, mean PaCO2 at the end of the doxapram period was significantly lower than the end of the placebo period (60 mm Hg against 67 mm M Hg). In three patients the rise in PaCO2 was accompanied by significant impairment in the level of consciousness which was reversed during the doxapram period. PaCO2 was not significantly different during either treatment period. No serious unwanted effects were encountered.

Acute Disease↗

PubMed1974