The early phase of critical illness is a progressive acidic state due to unmeasured anions.

BACKGROUND AND OBJECTIVE: Stewart's and Fencl's methods have recently been proposed to interpret acid-base disorders where traditional theory has proven inadequate. Our objectives were to evaluate: (1) the occurrence of acid-base disturbances in critically ill patients and their trend over the first 3 intensive care unit days, (2) whether Stewart's theory offers advantages over the traditional theory in the diagnosis of acid-base metabolic disturbances and (3) whether variables derived from Stewart's and Fencl's methods offer advantages over the traditional method to predict patient mortality. METHODS: A prospective cohort study in a general intensive care unit. Blood samples were analysed for arterial blood gases, electrolytes and proteins. PaCO2, pH, bicarbonate, base excess, standard base-excess, sodium, potassium, chloride, phosphorous, calcium, magnesium and lactate were measured. Anion gap, Stewart's and Fencl's variables were calculated. RESULTS: When using Stewart's method, metabolic acidosis and metabolic alkalosis were found in 92.9% and 93.4% of samples, respectively. Corresponding figures obtained with the traditional method were 15% and 18.7%. In 245 (64.5%) samples, Stewart's method revealed that metabolic acidosis and alkalosis were simultaneously present, whereas the traditional method revealed a normal acid-base status. Strong ion gap increased significantly over the first 3 intensive care unit days. Strong ion gap and lactate were independent predictors of 28-day mortality. CONCLUSIONS: Metabolic acidosis by unmeasured anions is a clinically relevant phenomenon, which is correlated with mortality. Progressive metabolic acidosis may be ongoing in the early phase of critical illness despite the absence of acidaemia.

Surveillance of infections acquired in intensive care: usefulness in clinical practice.

Nosocomial infection surveillance is common in the USA and in some European countries but in Italy few hospitals use it. In order to evaluate its usefulness in clinical practice we performed a one year prospective epidemiological study that included 178 patients, admitted to an intensive care unit (ICU) for more than 48 h. Median ICU stay was 16 days. Trauma and neurological diseases accounted for 65% of admissions. The selected population had high severity scores and required a large number of invasive procedures for diagnosis and therapy. The most common infections were: pneumonia 46/1000 ventilator-days; urinary tract infections 17/1000 catheter-days; central venous catheter infections 14.5/1000 catheter-days with 1.7/1000 CVC-related sepsis; bacteraemic sepsis 12/1000 ICU-days. The most frequent pathogens were Staphylococcus aureus,Pseudomonas aeruginosa, other Gram-negative aerobes and Candida spp. Antimicrobial resistance was substantial, with 68% methicillin-resistance in S. aureus and 76% of P. aeruginosa displaying antibiotic resistance. Severe sepsis or septic shock occurred in 30 patients (8/1000 ICU-days), and three patients died from septic shock of unknown origin (10% case fatality rate). There were no case fatalities for pneumonia and bacteraemic sepsis. Overall, ICU-acquired infections were not associated with an increased risk of death.

[Cancer incidence among active male workers at Electricite de France-Gaz de France]. / Incidence des cancers dans la population masculine des salariés en activité à Electricité de France et Gaz de France.

The social security department of the French national electric and gas company has established a cancer register among a population of about 150,000 active employees based on sick leaves of both short and long duration as well as deaths recorded along with their medical cause. A first study conducted in male workers, aged 20-59, during the 1978-1989 period showed a lower cancer incidence for almost every site of cancer except for leukaemias and others reticuloses tumors of lymphoid and histiocyte tissues, compared with the French general population (SIR = 148 and 218 resp.). Between the 1978-1982 and 1983-1989 periods, a marked decrease (statistically significant) was observed in the incidence of larynx cancer and cancers of all sites usually related with excessive alcohol consumption. During the same period the incidence of pancreatic cancer has almost doubled. Large variations according to socio-economic status were observed for cancers of the lung, the pharynx, the oral cavity and the oesophagus and, also, to a lesser degree, for tumours of the testis and the bladder and leukaemias. The results suggest further studies of occupational factors. Interest and limits of such a compagny register are discussed.