Renal physiology. Part II: Fluid and electrolyte regulation.

The comprehension of fluid and electrolyte and acid-base homeostasis is essential for the nurse caring for critically-ill neonates. This article discusses the means by which the kidney regulates fluid, sodium, and potassium, and its role in acid-base regulation. Under normal circumstances, the neonatal kidney is able to maintain homeostasis in these areas. However, the more premature an infant, the less able they are to maintain normal electrolyte, bicarbonate, or fluid balance. The understanding of renal filtration, absorption, and excretion requires knowledge of renal anatomy and the structure and function of the nephron unit. Regulation of glomerular filtration and renal blood flow plays an important part in determining the kidney's ability to maintain homeostasis (see Part I). Perhaps the greatest factor in determining renal function is the degree of maturity. Nephrogenesis is not complete until the 34th week of gestation. This, along with other factors, has a profound effect on glomerular filtration, renal filtration and absorption, and the nephron's sensitivity to hormonal control. The structural and functional differences in the neonatal kidney must be considered when evaluating renal function and devising a plan of care.

Oral dantrolene sodium for tonsillectomy pain: a double-blind study.

Tonsillectomy in adults and older children is typically accompanied by 7 to 14 days of pain. On the basis of clinical observations of patients treated perioperatively with dantrolene sodium for malignant hyperthermia, we hypothesized that pharyngeal muscle spasms are a major factor in tonsillectomy pain. We entered 113 patients, 11 years of age and older, into a double-blind, placebo-controlled study to evaluate the effectiveness of dantrolene sodium in reduction of tonsillectomy pain. Patients were randomly assigned either dantrolene (1.5 mg/kg per day) or placebo orally four times a day for 5 days postoperatively. On a standardized questionnaire, the patient recorded pain, diet, activity level, analgesics, and side effects, daily for 2 weeks. Also, alkaline phosphatase (alk phos) and serum aspartate aminotransferase (SGOT) levels were determined before the operation and 2 weeks after. Patients who received dantrolene had no significant differences in subjective pain, diet, or activity level scores from those of patients who received placebo. Dantrolene patients did, however, require significantly less analgesic use than placebo patients (p = 0.034, 0.015, and 0.005 for postoperative days 2, 3, and 4, respectively). There was no significant difference in side effects or changes in liver enzyme between the dantrolene and placebo groups. We conclude that dantrolene sodium, given in the dosage noted, is effective in reduction of analgesic requirements after tonsillectomy.

Experimental procedure for testing the effects of low level antibiotic feeding and therapeutic treatment on Salmonella typhimurium var. copenhagen infection in broiler chicks.

Procedures are described for determining the effects of low level antibiotic feed additives in broiler chick rations when chicks are artificially infected with Salmonella typhimurium var. copenhagen and the effectiveness of the same antibiotics used therapeutically for salmonellosis. These procedures also permit study of development of antibiotic resistant enteric flora related to antibiotic feeding and the transferability of the resistance. Measures should be taken to monitor and assure minimal extraneous bacterial contamination of eggs, chicks, feed and facilities and minimize baseline antibiotics resistance. Facilities and equipment should be fumigated extensively, chicks should be from primary breeder flocks off antibiotics for two generations, handled minimally, and fed all-vegetable protein rations. Optimum procedures for oral induction of salmonellosis with a chick-virulent strain of Salmonella typhimurium var. copenhagen are reported. Effects of low level antibiotic feeding and subsequent therapeutic level feeding of infected and control birds are measured by mortality, feed efficiency and weight gain, and microbiological analyses of fecal samples, intestinal samples and necropsied dead chicks. Gathering all data possible from all facets of the trials is imperative for ascertaining antibiotic effects.

Increased survival in calves of Escherichia coli K-12 carrying an Ent plasmid.

Escherichia coli K-12 strains with and without an Ent plasmid were fed to calves, and the survival of each was monitored by viable bacterial counts of the feces. The E. coli K-12 strain carrying the Ent plasmid survived in the calves at significantly higher levels and for a longer period of time than the E. coli F(-) stain.