Effect of pethidine administered during the first stage of labor on the acid-base status at birth.

OBJECTIVE: To evaluate the association between the use of pethidine during the first stage of labor and the presence, type and timing of acidosis in the newborn at birth. STUDY DESIGN: Secondary data analysis of a randomized controlled trial, which included term singleton pregnancies diagnosed with dystocia and requiring active management of labor. Women were randomized to receive either 100 mg of pethidine or placebo. Statistical analyses were performed using chi(2) or Fisher's exact tests for proportions and multiple linear regression for continuous outcomes. RESULTS: Three hundred and eighty-three pregnant women with a valid arterial blood cord sample were included in the final analysis. Lower pH and bicarbonate levels, as well as higher pCO(2) levels were found in the pethidide group. A higher incidence of acidosis was found in the pethidine group (pH<7.12 OR: 8.59 95% C.I. 3.29, 22.46). The highest frequency of acidosis was encountered when pethidine-delivery interval was 5 h. CONCLUSION: Pethidine use during the first stage of labor was associated with an increased risk of acidosis at birth.

Mortality from lung and kidney disease in a cohort of North American industrial sand workers: an update.

BACKGROUND: A previously published cohort study of some 2670 employees of the North American sand industry, followed through 1994, provided strong evidence of a causal relationship between quartz exposure and death from both silicosis and lung cancer, after allowance for cigarette smoking and in the absence of known occupational carcinogens. Unexpectedly, a significant excess mortality from chronic non-malignant renal disease [observed 16; expected 7.6; standardized mortality ratio (SMR) 212] was also found, whereas deaths from renal cancer at this stage were close to expectation (observed 6; expected 5.2). OBJECTIVES: Our primary aim was to discover whether death from chronic renal disease was related to the estimated intensity of crystalline silica exposure. A further aim was to determine whether or not our previous estimates of lung cancer and silicosis risk were confirmed by mortality in the cohort 6 years later. METHODS: With help from the US National Death Index, surviving members of the cohort, with the exception of employees of a small plant in Canada, were traced through 2000. The cause of death was determined for all who had died, for comparison against National and State mortality rates. Nested case-referent analyses were then undertaken, as previously, of deaths from lung cancer and silicosis, plus end-stage renal disease and kidney cancer, in relation to quantitative re-estimates of quartz exposure. RESULTS: The total number of deaths through 1994 was 990; there were 231 additional deaths during the period 1995-2000. The SMRs were significantly higher in the later than the earlier period, mainly due to a relative increase in heart disease and external causes. The updated odds ratios for lung cancer and silicosis were almost identical to those published previously, with lung cancer risk again related to average silica concentration and cumulative exposure, but not to length of employment. In contrast, risks of neither end-stage renal disease nor renal cancer were related to cumulative exposure, although now based on 19 cases (SMR 239), and 10 cases (SMR 202), respectively, in fact, opposite trends were apparent for both diseases. However, because of the small numbers there was only limited power to assess the statistical significance of these trends or of any separate relationship with the duration or intensity of exposure. CONCLUSIONS: Our findings support a causal relationship between lung cancer and quartz exposure after allowance for cigarette smoking, in the absence of other known carcinogens, but failed to find similar evidence to explain the excess mortality from either chronic renal disease or kidney cancer.