The effect of propofol on the neutrophil respiratory burst.

We have examined the effect of propofol on the neutrophil respiratory burst. Chemiluminescence was used as a measure of the respiratory burst following stimulation with 10(-5) M N-formyl-L-methionyl-L-leucyl-L-phenylalanine. Propofol 1.25, 2.5 and 5.0 x 10(-5) M inhibited neutrophil chemiluminescence by 29.6, 43.0 and 57.6%, respectively, in neutrophils prepared from healthy adult volunteers, and by 25.5, 37.4 and 54.7% in cells from patients with severe sepsis. We conclude that propofol interferes with the ability of human neutrophils to generate reactive oxygen species.

Nocturnal hypoxaemia in late pregnancy.

We have measured arterial oxygen saturation (SpO2) continuously overnight in 13 non-pregnant (NP), 13 pregnant normotensive (NPIH) and 15 pregnant patients with a diagnosis of pregnancy-induced hypertension (PIH). The two pregnant groups did not differ in duration of pregnancy (> 35 weeks) and none was in labour. There was no significant difference in age between these three groups. Mean SpO2 in group NP was 98.5% (range 97-99%). This was significantly higher than that in group NPIH (95.2 (91-98) %) and group PIH (94.9 (89-99) %). In seven pregnant patients, more than 20% of the recording was spent with an SpO2 < 90%. We conclude that a significant number of pregnant women (> 35 weeks' gestation) suffer from prolonged nocturnal hypoxaemia.

The gastrointestinal tract after anaesthesia.

Gastrointestinal tract motility may be reduced markedly after surgery with delay in gastric emptying. these alterations are induced partly by surgery, partly by the residual effects of anaesthetic agents, and particularly by opioids administered for post-operative pain relief. These changes may be antagonized to a certain extent by administration of prokinetic agents such as cisapride. Post-operative ileus reduces the rate of mobilization and may also reduce or delay absorption of drugs administered by the gastrointestinal tract. Furthermore, post-operative nausea and vomiting, multi-factorial in aetiology, may ensue and also be responsible for delayed mobilization, subjective discomfort and delay in administration of oral agents post-operatively. A serious problem may be leakage from bowel anastomoses. Although the causes are primarily surgical, an increase in bowel contractility may be deleterious and it has been suggested that neostigmine and morphine may be implicated in anastomotic dehiscence.

Effects of hypoxemia on the electroretinogram in diabetics.

PURPOSE: To identify any relationship between retinal dependence on oxygen and the presence or absence of retinopathy in a group of patients with the same duration of diabetes, based on the proposal that diabetic retinopathy results from long-term adaptation to the Crabtree effect, i.e., reduction of oxidative phosphorylation caused by increased intracellular glucose concentrations. METHODS: Electroretinograms were recorded on 17 patients with insulin-dependent diabetes (of 15 to 17 years duration) and 10 healthy controls. Recordings were made under normal conditions and then after 4 min of hypoxemia (oxygen saturation, 80%). Retinopathy status was assessed from fundus photographs. RESULTS: Electroretinogram b-wave amplitudes of seven patients without retinopathy were reduced to 69% by the hypoxemia compared to a reduction to 88% for 10 patients with retinopathy (p = 0.039). CONCLUSIONS: The relative sensitivity to hypoxemia of patients without retinopathy suggests greater dependence on oxidative phosphorylation than in patients with retinopathy. The results appear to be consistent with the Crabtree effect hypothesis. Downregulation of tissue oxygen consumption by the Crabtree effect would lead to a reduction of retinal blood flow by autoregulation and to a reduced concentration of adenosine triphosphate in the retina.