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Biomedical subjects

N F Pierce

Publications and source records attributed to N F Pierce.

At least 19 recordsLinked to original sources

Quality of hospital care for seriously ill children in less-developed countries.

BACKGROUND: Improving the quality of care for sick children referred to hospitals in less-developed countries may lead to better outcomes, including reduced mortality. Data are lacking, however, on the quality of priority screening (triage), emergency care, diagnosis, and inpatient treatment in these hospitals, and on aspects of these potential targets that would benefit most from interventions leading to improved health outcomes. METHODS: We did a qualitative study in 13 district hospitals and eight teaching hospitals in seven less-developed countries. Experienced paediatricians used a structured survey instrument to assess initial triage, emergency and inpatient care, staff knowledge and practices, and hospital support services. FINDINGS: Overall quality of care differed between countries and among hospitals and was generally better in teaching hospitals. 14 of 21 hospitals lacked an adequate system for triage. Initial patient assessment was often inadequate and treatment delayed. Most emergency treatment areas were poorly organised and lacked essential supplies; families were routinely required to buy emergency drugs before they could be given. Adverse factors in case management, including inadequate assessment, inappropriate treatment, and inadequate monitoring occurred in 76% of inpatient children. Most doctors in district hospitals, and nurses and medical assistants in teaching and district hospitals, had inadequate knowledge and reported practice for managing important childhood illnesses. INTERPRETATION: Strengthening care for sick children referred to hospital should focus on achievable objectives with the greatest potential benefit for health outcome. Possible targets for improvement include initial triage, emergency care, assessment, inpatient treatment, and monitoring. Priority targets for individual hospitals may be determined by assessing each hospital.

Adolescent↗

Rice-based oral rehydration solution for treating diarrhoea.

BACKGROUND: Oral rehydration therapy is used to treat dehydration caused by diarrhoea. However the rehydration solution does not reduce stool loss or length of illness. A solution able to do this may lessen the use of ineffective diarrhoea treatments as well as improve morbidity and mortality related to diarrhoea. OBJECTIVES: The objective of this review was to assess the effects of rice-based oral rehydration salts solution compared with glucose-based oral rehydration salts solution on reduction of stool output and duration of diarrhoea in patients with acute watery diarrhoea. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline, Embase, Lilacs and the reference lists of relevant articles. We also contacted researchers in the field. SELECTION CRITERIA: Randomized trials comparing standard World Health Organization oral rehydration solution with an experimental oral rehydration salts solution in which glucose (20 grams per litre) was replaced by 50-80 grams per litre of rice powder, with the electrolytes remaining unchanged. DATA COLLECTION AND ANALYSIS: Data were extracted independently by a statistician and a clinician. MAIN RESULTS: Twenty-two trials were included. Concealment of allocation was adequate in 15 of these trials. Irrespective of age, people with cholera who were given rice oral rehydration salts solution had substantially lower rates of stool loss than those given oral rehydration salts solution in the first 24 hours. Mean stool outputs in the first 24 hours were lower by 67 millilitres/kg of body weight (weighted mean difference -67.4, 95% confidence interval -94.3 to -41.0) in children, and by 51 millilitres/kg of body weight (weighted mean difference -51.1, 95% confidence interval -65.9 to -36.3) in adults. The rate of stool loss in infants and children with acute non-cholera diarrhoea was reduced by only four millilitres/kg of body weight (weighted mean difference -4.3, 95% confidence interval -9.3 to 0.8). REVIEWER'S CONCLUSIONS: Rice-based oral rehydration appears to be effective in reducing stool output in people with cholera. This effect was not apparent in infants and children with non-cholera diarrhoea.

Adult↗

Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates. Studies are in progress to define the optimal formulation of reduced-osmolarity glucose-based ORS.

Carbohydrate Metabolism↗

Cholera treatment.

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Administration, Oral↗

Is a low-osmolarity ORS solution more efficacious than standard WHO ORS solution?

The clinical efficacy of a diluted oral rehydration salts (ORS) solution was compared in a pilot study with that of intravenous (i.v.) therapy and of standard World Health Organization (WHO)/United Nations Childrens Fund (UNICEF) ORS solution in children with acute diarrhea. Sixty-one boys aged 3 to 24 months, admitted to hospital with acute diarrhea and signs of dehydration, were randomly assigned to groups receiving standard ORS solution, diluted ORS solution, or i.v. therapy. In children treated with standard ORS solution and small amounts of plain water, the total fluid intake was 25-39% greater, the stool output was 58-77% greater (p < 0.01), and the duration of diarrhea was 30-55% greater than in the other treatment groups. Intake of plain water, taken separately or added to the ORS solution, was greater in children given diluted ORS solution (73 +/- 23 ml/kg) than in those given standard ORS solution (21 +/- 32 ml/kg) (p < 0.001). The mean serum sodium concentration increased by 2.2 mEq/L in children given standard ORS solution, whereas it decreased by 2.9 mEq/L in those given diluted ORS solution. This study shows that some children develop worsening diarrhea and increasing serum sodium concentrations when treated with standard ORS solution and given only small amounts of plain water. This is probably caused by the slight hypertonicity of standard ORS solution combined with transient partial glucose malabsorption. This can be avoided if water, breast milk, or another low-solute drink is given liberally during maintenance therapy with ORS solution, as recommended by the WHO.

Acute Disease↗

Clinical trials of improved oral rehydration salt formulations: a review.

Reviewed are all the published clinical trials of glycine-based oral rehydration salts (ORS), L-alanine-based ORS, L-glutamine-based ORS, maltodextrin-based ORS, and rice-based ORS, as well as the results of several recently completed, but unpublished, studies of these formulations that were supported by WHO. All experimental ORS formulations contained the same concentrations of salts as citrate-based WHO-ORS; all trials were randomized comparisons with WHO-ORS, and all except those with rice-based ORS were double-blind studies. The rate of stool loss and, less frequently, the duration of diarrhoea were used as indicators of clinical performance to compare ORS formulations. The following conclusions were reached concerning the efficacy and use of modified ORS formulations. Rice-based ORS (50 g/l) is superior to WHO-ORS for patients with cholera, and for such patients it can be recommended in any situation where its preparation and use are practical. Rice-based (50 g/l) and WHO-ORS solutions are equally effective for treating children with acute non-cholera diarrhoea, when feeding is resumed promptly following initial rehydration, as has been consistently recommended by WHO. Since rice-based ORS is not superior to WHO-ORS for such children, there is no apparent reason to advise a change from glucose to pre-cooked rice in the recommended formulation for WHO-ORS. Maltodextrin-based ORS formulations (50 g/l) and WHO-ORS appear to be equally effective for treating children with acute non-cholera diarrhoea; there is no reason to advise a change from glucose to maltodextrin in the recommended formulation for WHO-ORS. Amino-acid-containing ORS formulations are not recommended for either non-cholera or cholera diarrhoea, since they are more costly and have no clinical advantage over WHO-ORS for children with acute non-cholera diarrhoea or over rice-based ORS for persons with cholera.

Child, Preschool↗

Impact of rice based oral rehydration solution on stool output and duration of diarrhoea: meta-analysis of 13 clinical trials.

OBJECTIVE: To define the benefit of rice oral rehydration salts solution in relation to the glucose based World Health Organisation oral rehydration salts solution for treating and preventing dehydration in patients with severe dehydrating diarrhoea. DESIGN: Meta-analysis using data from 13 available randomised trials that compared these two formulations. SUBJECTS: The studies compared 1367 patients with cholera, severe cholera-like diarrhoea, or acute non-cholera diarrhoea. 668 received the standard WHO solution and 699 the rice based solution. INTERVENTION: Each trial report was reviewed to determine patient eligibility, the number of patients who were randomised and the number of these excluded from analysis, details of the randomisation procedure, and the precise timing of the outcome measurements. MAIN OUTCOME MEASURES: Stool output during the first 24 hours; weighted estimates of the difference in mean stool output between treatments. RESULTS: The rice solution significantly reduced the rate of stool output during the first 24 hours by 36% (95% confidence interval 28 to 44%) in adults with cholera and by 32% (19 to 45%) in children with cholera. The rate of stool loss in infants and children with acute non-cholera diarrhoea was reduced by only 18% (6 to 30%). CONCLUSIONS: The benefit of rice oral rehydration salts solution for patients with cholera is sufficiently great to warrant its use in such patients. The benefit is considerably smaller for children with acute, noncholera diarrhoea and should be more precisely defined before its practical value can be judged.

Bicarbonates↗

Cholera in Africa: lessons on transmission and control for Latin America.

In January, 1991, epidemic cholera emerged in Peru and spread to 7 other countries of Latin America. Cholera was introduced 20 years ago to Africa, where it spread rapidly to 30 of the 46 countries of the region and by 1990 accounted for 90% of all cases reported to the World Health Organisation. Many lessons from the cholera epidemic in Africa are relevant to efforts to control the disease in Latin America. Public health practices from the past--quarantine and cordon sanitaire to halt introduction of cholera by travellers, and vaccination and mass chemoprophylaxis to control epidemics--are ineffective in preventing spread of the disease. Cholera can be transmitted not only by contaminated water but also by food. Social phenomena such as mass migrations and burial practices may play a greater role than previously understood. While efforts to prevent the spread of cholera have been ineffective, cholera-associated mortality can be decreased with rehydration therapy. Since the current pandemic is unlikely to retreat soon, new strategies are urgently needed to control the spread of cholera through sanitary and behavioural interventions or improved vaccines.

Africa↗

Determinants of immunogenicity and mechanisms of protection by virulent and mutant Vibrio cholerae O1 in rabbits.

The colonizing capacities of 16 Vibrio cholerae strains, including nine genetically and/or phenotypically defined parent-mutant pairs, were determined in unobstructed adult rabbit small bowel. There were marked interstrain differences in colonizing capacity, which was enhanced by bacterial motility and the production of cholera holotoxin but was unrelated to production of cholera toxin B-subunit or hemolysin or to bacterial serotype or biotype. The role of colonizing capacity and other bacterial features in determining the immunizing efficiency of live V. cholerae was studied by determining the efficiency with which graded inocula of each strain immunized against attempted recolonization of the ileum or induction of choleralike diarrhea by the RITARD (removable intestinal tie-adult rabbit diarrhea) challenge technique using standard inocula of virulent V. cholerae. Mucosal colonizing capacity was the only quantitative predictor of bacterial immunizing capacity; none of the other bacterial features cited above influenced bacterial immunogenicity against either type of challenge, except as they affected colonizing capacity. Live V. cholerae immunized much more efficiently than Formalin-killed bacteria; the former caused marked protection after a single inoculum of 10(2) CFU, whereas the latter gave only partial protection after three inoculations of 10(11) killed organisms. Protection induced by live bacteria was due largely to resistance to colonization and included marked inhibition of bacterial growth within the bowel lumen. These findings strongly suggest that an optimally efficient oral cholera vaccine would be composed of avirulent live V. cholerae selected for their capacity to colonize the small-bowel mucosa.

Administration, Oral↗

Determinants of the immunogenicity of live virulent and mutant Vibrio cholerae O1 in rabbit intestine.

Determinants of the capacity of live Vibrio cholerae O1 isolates to evoke specific immune responses in intestinal mucosa were studied in rabbits, using mucosal immunoglobulin A (IgA) antitoxin as the measured immune response. Antitoxin responses were evoked mostly by the primary inoculation and were dose dependent; secondary-type responses were modest and occurred only when the booster inoculum was large, i.e., 10(10) CFU. The efficiency of mucosal immunization correlated closely with the mucosal colonizing capacity of the infecting strain and was otherwise independent of toxin genotype (A+ B+ or A- B+) or whether the strain was motile or nonmotile. Live bacteria evoked mucosal antitoxin more efficiently than did purified cholera toxin. Prior immunization with a nontoxinogenic (A- B-) V. cholera strain interfered significantly with the induction of mucosal antitoxin by subsequent immunization with its fully toxinogenic (A+ B+) parent. These results demonstrate the marked efficiency with which live V. cholerae stimulate a specific enteric mucosal secretory IgA response. They support the view that mucosal colonization aids efficient delivery of bacterial antigens to responsive subepithelial lymphoid tissue. This might occur by transfer of colonizing bacteria through M cells into Peyer patches or by efficient delivery of secreted toxin to M cells by mucosa-associated organisms. Preexisting antibacterial immunity interferes with colonization, which may prevent efficient antigenic stimulation and which may explain the relatively weak response to booster immunization. The same process may also limit the efficacy of hybrid enteric bacterial vaccines when there is preexisting mucosal immunity to the carrier organism due to either natural exposure or prior immunization with another vaccine that uses the same carrier.

Animals↗