No abstract

Ventilatory and metabolic changes were measured in seven patients undergoing high efficiency hemodialysis using a cuprophane dialyzer and bicarbonate-containing dialysate. At an HCO3 concentration of 35 mEq/liter and a mean in vivo urea clearance of 3.6 ml/kg/min, hypoxemia was not detected during dialysis (PaO2 was 14.00 and 13.60 kPa before and during dialysis). The new findings, related to high efficiency bicarbonate dialysis, include a sustained rise in minute ventilation (VE, 6.1 to 6.8 liter/min, P less than 0.01), an increase in CO2 excretion (VCO2, 194 to 214 ml/min, P less than 0.05), and O2 consumption (VO2, 215 to 246 ml/min, P less than 0.05). The increment in VE and VCO2 was attributed to the high flux rate of bicarbonate while the rise in VO2 is likely the result of metabolic alkalosis. Arterial pH rose from 7.40 to 7.49 mm Hg and serum HCO3 increased from 23.8 to 29.2 mEq/liter, while pCO2 remained normal at 5.07 kPa throughout the study. The acid-base status of the blood changed from that of a metabolic acidosis to that of a respiratory acidosis across the dialyzer where the pH decreased from 7.47 to 7.41 and pCO2 rose from 5.31 to 7.72 kPa. These data indicate that a healthy ventilatory response is needed to excrete the excess CO2 generated during high efficiency bicarbonate hemodialysis. The significance and etiology of the elevated O2 consumption is undetermined.

In 22 patients undergoing elective surgery, adrenal function was assessed before and on the day of surgery. Patients receiving corticosteroid therapy but with a normal cortisol response to a corticotropin stimulation tcit (group II, n = 8) were not given hydroconisone on the day of operation. Their cortisol concentration increased in a manner similar to patients (group I, n = 8) who had never had corticosteroid treatment. The plasma cortisol concentrations in these two groups were less than in subjects (group III, n = 6) with an impaired cortisol response to corticotropin stimulation, who were given hydrocortisone 25 mg at the induction of anaesthesia followed by a continuous infusion of hydrocortisone 100 mg during the next 24 h. There were no clinical signs of circulatory insufficiency in any group. The low-dose hydroconisone therapy regimen is sufficient for substitution of adrenal function during surgery and in the early postoperative phase. It could lead to mild oversubstitution in patients with impaired adrenal insufficiency undergoing major surgery.

No abstract

To evaluate the reliability of capnography in identifying esophageal intubation in the presence of a carbonated beverage in the stomach, we first investigated the amount of CO2 released from different carbonated beverages and antacids in a simulated stomach; next we measured the end-expired CO2 level during esophageal ventilation with a carbonated beverage in the stomachs of six swine. CO2 levels of approximately 20% were consistently observed in all carbonated beverages. The CO2 levels obtained with sodium bicarbonate, Maalox, and sodium citrate were 19.3%, 2.0%, and 0%, respectively. CO2 waveforms were observed during esophageal ventilation in five of six animals after intragastric administration of a carbonated beverage. An end-expired CO2 level of 2.5% or more was observed in two swine. The highest end-expired CO2 level measured was 5.3%. We conclude that although capnography is convenient and effective, it lacks all the attributes of an ideal monitor for detecting esophageal intubation.

No abstract

Continuous fiberoptic measurement of mixed venous oxygen saturation (SvO2) via a pulmonary artery catheter is a useful, though invasive, monitoring technique. Continuous right atrial venous oxygen saturation measurement by oximetry offers the potential of a significantly less invasive SvO2 measurement. However, catheter motion, character of the vessel, chamber wall reflection, the filtering technique involved in calculating oxygen saturation, and the streaming of venous blood prior to ventricular mixing may influence the feasibility of continuous right atrial (RA) SvO2 measurement. This study investigated the performance of fiberoptically measured RA SvO2, at a position 2 cm from the tricuspid valve, relative to simultaneously measured pulmonary artery (PA) SvO2. Ten pigs were subjected to circulatory shock or chemically induced lung damage. Over a total monitoring period of approximately 40 hours, 464 paired data points were sampled at 5-minute intervals. The difference between the overall means of RA and PA SvO2 was 0.91% with a standard error of the estimate of 4.7%, a regression equation of RA SvO2 = PA SvO2 (0.94 + 2.1) PA So2, and a correlation coefficient of 0.94. Our conclusion, although extrapolated from a pig model, is that fiberoptic SvO2 monitoring may be accomplished less invasively and at a lower cost with a right atrial catheter.

The prevalence of protein-energy malnutrition (PEM) was examined in 1206 randomly selected elderly people aged 65 to 80 years living in their own homes. Nutritional assessment was based on weight loss, weight index, triceps skin fold, arm muscle circumference, serum albumin and prealbumin, and delayed cutaneous hypersensitivity (DCH) reaction. The prevalence of PEM was 5 per cent. If people with signs of inflammation were excluded, the prevalence of PEM was 3.5 per cent. When other nutritional indices, used by other authors among hospitalized patients, were applied to our sample prevalence values from 2.6 to 4.1 per cent were obtained. the prevalence was not related to sex or age. DCH increased the sensitivity of the screening method but causes of anergy other than PEM must be taken into account. It is concluded that PEM, in a degree shown to impair the prognosis at hospital, does occur among elderly people at home in an industrialized country.