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The Cochrane Database of Systematic... Dec 2012Perioperative fluid therapy influences clinical outcomes following major surgery. Fluid preparations may be based on a simple non-buffered salt solution, such as normal... (Review)
Review
BACKGROUND
Perioperative fluid therapy influences clinical outcomes following major surgery. Fluid preparations may be based on a simple non-buffered salt solution, such as normal saline, or may be modified with bicarbonate or bicarbonate precursor buffers, such as maleate, gluconate, lactate or acetate, to better reflect the human physiological state. These latter fluids have theoretical advantages over normal saline in preventing hyperchloraemic acidosis. A number of clinical studies have now compared fluid preparations with and without a buffer to achieve a balanced electrolyte solution for perioperative fluid resuscitation.
OBJECTIVES
To review the safety and efficacy of perioperative administration of buffered versus non-buffered fluids for plasma volume expansion or maintenance in adult patients undergoing surgery.
SEARCH METHODS
We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 4), MEDLINE (1966 to May 2011), EMBASE (1980 to May 2011), and CINAHL (1982 to May 2011). We handsearched conference abstracts and where possible, contacted leaders in the field.
SELECTION CRITERIA
We only included randomized trials of buffered versus non-buffered intravenous fluids for perioperative fluid resuscitation. The trials with other forms of comparisons such as crystalloids versus colloids and colloids versus different colloids were excluded. We also excluded trials using hypertonic fluids and dextrose-based fluids.
DATA COLLECTION AND ANALYSIS
Two authors independently extracted data and assessed the methodological quality of clinical trials. We resolved any disagreements by discussion. We contacted the trial authors to provide additional information where appropriate. We presented pooled estimates of the dichotomous outcomes as odds ratios (OR) and on continuous outcomes as mean differences, with 95% confidence intervals (CI). We analysed data on Review Manager 5.1 using fixed-effect models, and when heterogeneity was high (I² > 40%) random-effect models were used.
MAIN RESULTS
We identified 14 publications reporting 13 trials or comparisons with a total of 706 participants. For many of the outcomes reported, there was significant clinical and statistical heterogeneity. The primary outcome of mortality at any time was reported in only three studies with a total of 267 patients. The mortality rate was 2.9% for the buffered fluids group and 1.5% for the non-buffered fluids group but this difference was not statistically significant. The Peto OR was 1.85 (95% CI 0.37 to 9.33, P = 0.45, I(2)= 0%). Organ dysfunction was only presented for renal impairment. There was no difference in renal insufficiency leading to renal replacement therapy between the buffered and non-buffered groups (OR 0.61, 95% CI 0.23 to 1.63, P = 0.32, I(2) = 0%). Markers of organ system failure as assessed by urine output, creatinine and its variables (for renal function), PaC0(2) (respiratory function) and postoperative nausea and vomiting (gastro-intestinal function) showed a statistically significant difference only in PaC0(2) levels. The mean difference was 1.18 with lower PaC0(2) levels in the non-buffered fluid group (95% CI 0.09 to 2.28, P = 0.03, I(2) = 0%) compared to the buffered fluid group.There was no difference in intraoperative blood loss nor the volumes of intraoperative red cell or fresh frozen plasma transfused between groups. There was an increase in platelet transfusion in the non-buffered group which was statistically significant after analysing the transformed data (log transformation because the data were highly skewed).A number of metabolic differences were noted. There was a difference in postoperative pH of 0.06 units, lower in the non-buffered fluid group (95% CI 0.04 to 0.08, P < 0.00001, I(2) = 74%). However, this difference was not maintained on postoperative day one. The non-buffered fluid group also had significantly greater base deficit, serum sodium and chloride levels.There was no difference demonstrated in length of hospital stay and no data were reported on cost or quality of life.
AUTHORS' CONCLUSIONS
The administration of buffered fluids to adult patients during surgery is equally safe and effective as the administration of non-buffered saline-based fluids. The use of buffered fluids is associated with less metabolic derangement, in particular hyperchloraemia and metabolic acidosis. Larger studies are needed to assess robust outcomes such as mortality.
Topics: Adult; Buffers; Fluid Therapy; Humans; Perioperative Care; Plasma Substitutes; Randomized Controlled Trials as Topic; Surgical Procedures, Operative
PubMed: 23235602
DOI: 10.1002/14651858.CD004089.pub2 -
Annals of Emergency Medicine Dec 2009Metformin is known to cause potentially fatal metabolic acidosis with an increased lactate level in both overdose and therapeutic use. No association between mortality... (Comparative Study)
Comparative Study Meta-Analysis Review
STUDY OBJECTIVE
Metformin is known to cause potentially fatal metabolic acidosis with an increased lactate level in both overdose and therapeutic use. No association between mortality and serum pH, lactate level, or metformin concentrations, though intuitive, has yet been described. This systematic literature review is designed to evaluate the association between mortality and serum pH, lactate level, and metformin concentrations in acute metformin overdose.
METHODS
We reviewed the literature by using the MEDLINE, EMBASE, CINAHL, and TOXNET databases for cases of metformin overdose with documented mortality data and values of serum pH, lactate level, and metformin concentrations. When available, patient age, patient sex, and whether patients received intravenous sodium bicarbonate therapy or hemodialysis were also analyzed. Cases meeting inclusion criteria were analyzed to determine whether a difference in distribution of nadir serum pH, peak serum lactate level, or peak serum metformin concentrations existed between overdose survivors and nonsurvivors.
RESULTS
We identified 10 articles that had 1 or more cases meeting our inclusion criteria. In total, there were 22 cases of metformin overdose (5/22 died) that met inclusion criteria. No intentional overdose patients died whose serum pH nadir was greater than 6.9, maximum lactate concentration less than 25 mol/L, or maximum metformin concentration less than 50 microg/mL (therapeutic range 1 to 2 microg/mL). Intentional overdose patients with a nadir serum pH less than 6.9 had 83% mortality (5/6), those with lactate concentration greater than 25 mmol/L had 83% mortality (5/6), and those with metformin concentration greater than 50 microg/mL had 38% mortality (5/12). Nadir serum pH and peak serum lactate and metformin concentration distributions in survivors and nonsurvivors revealed that survivors had a median nadir pH of 7.30, interquartile range (IQR) 7.22, 7.36; nonsurvivors, a median nadir pH of 6.71, IQR 6.71, 6.73; survivors, a median peak lactate level of 10.8 mmol/L, IQR 4.2, 12.9; nonsurvivors, a median peak lactate level of 35.0 mmol/L, IQR 33.3, 39.0; survivors, a median peak metformin level of 42 microg/mL, IQR 6.6, 67.6; and nonsurvivors, a median peak metformin level of 110 microg/mL, IQR 110, 110.
CONCLUSION
No cases of acute metformin overdose meeting the study's inclusion criteria were found in which patients with a nadir serum pH greater than 6.9, peak serum lactate concentrations less than 25 mmol/L, or peak serum metformin concentrations less than 50 microg/mL died. Patients with acute metformin overdose who died had much lower serum pH nadirs and much higher peak serum lactate and metformin concentrations than those who survived.
Topics: Acidosis, Lactic; Acute Disease; Adult; Drug Overdose; Female; Humans; Hydrogen-Ion Concentration; Hypoglycemic Agents; Lactic Acid; Male; Metformin; Middle Aged; Survival Analysis
PubMed: 19556031
DOI: 10.1016/j.annemergmed.2009.04.023 -
Annales de Biologie Clinique 2004To identify, through a systematic review of the literature, the laboratory variables that, in addition to performance status and to extent of the disease, would allow a... (Review)
Review
OBJECTIVE
To identify, through a systematic review of the literature, the laboratory variables that, in addition to performance status and to extent of the disease, would allow a more accurate stratification of small-cell lung cancer patients who participate in chemotherapy trials, with or without radiotherapy. Secondary aim: to compare the results of our systematic review with the recommendations made in current clinical practice guidelines.
METHODS
Update of two recently published systematic reviews, without meta-analysis, following the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine, and taking into account the Consolidated Standards of Reporting Trials statement.
RESULTS
Of 1143 publications retrieved, exclusion and inclusion criteria allow us to include 13 studies in our review. The three variables which were the most often found significant in multivariate statistical analysis, were: pre-therapeutic levels of laboratory variables (13/13), performance status (12/13), and degree of tumour invasion (10/10). Among the laboratory variables, serum lactate dehydrogenase (LDH) is the only one that was quite consistently found to be of independent prognostic significance, with p values or hazard ratios quite close to those obtained with performance status, or with extent of the disease. The recommendations made in the four clinical practice guidelines that we retrieved, are often vague regarding laboratory variables, and sometimes they even contradict each others.
CONCLUSIONS
Available evidence would support the recommendation that pretreatment LDH should be systematically measured in order to stratify patients in therapeutic trials. If other laboratory variables were to be measured in addition to LDH for this purpose, it seems that alkaline phosphatase (ALP), and to a lesser extent, sodium and white blood cell counts, might be the best suited ones. Nevertheless, further studies are necessary to more clearly support this latter recommendation. Available evidence would not support the measurement of any other laboratory variable in this context, before, during, or after treatment. Our recommendations are more in agreement with the recommendations made in the clinical practice guidelines that use evidence-based methods than with the guidelines that do not.
Topics: Carcinoma, Small Cell; Clinical Laboratory Techniques; Clinical Trials as Topic; Humans; Lung Neoplasms; Practice Guidelines as Topic
PubMed: 15047471
DOI: No ID Found -
The Cochrane Database of Systematic... 2002Many women experience leg cramps in pregnancy. They become more common as pregnancy progresses and are especially troublesome at night. (Review)
Review
BACKGROUND
Many women experience leg cramps in pregnancy. They become more common as pregnancy progresses and are especially troublesome at night.
OBJECTIVES
The objective of this review was to assess methods of preventing and treating leg cramps in pregnancy.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group trials register (October 2001).
SELECTION CRITERIA
Randomised trials of treatments for leg cramps in pregnancy.
DATA COLLECTION AND ANALYSIS
Trial quality was assessed and data were extracted independently by two reviewers.
MAIN RESULTS
Five trials involving 352 women were included. The trials were of moderate quality. The only placebo-controlled trial of calcium treatment showed no evidence of benefit. Trials comparing sodium chloride with placebo (odds ratio 0.54, 95% confidence interval 0.23 to 1.29) and calcium with sodium chloride (odds ratio 1.23, 95% confidence intervals 0.47 to 3.27 ) showed no evidence of benefit. Placebo controlled trials of multivitamin with mineral supplements (odds ratio 0.23, 95% confidence intervals 0.05 to 1.01) and magnesium (odds ratio 0.18, 95% confidence intervals 0.05 to 0.60) provided some suggestion of benefit.
REVIEWER'S CONCLUSIONS
The evidence that calcium reduces cramp is weak and seems to depend on placebo effect. The evidence for sodium chloride is stronger but the results of the sodium chloride trial may no longer be relevant because of dietary changes which include an increased sodium intake in the general population. It is not possible to recommend multivitamins with mineral supplementation, as it is not clear which ingredient, if any, is helping. If a woman finds cramp troublesome in pregnancy, the best evidence is for magnesium lactate or citrate taken as 5mmol in the morning and 10mmol in the evening.
Topics: Female; Humans; Leg; Muscle Cramp; Pregnancy; Pregnancy Complications
PubMed: 11869565
DOI: 10.1002/14651858.CD000121 -
The Cochrane Database of Systematic... 2000Preterm rupture of membranes places a fetus at risk of cord compression and amnionitis. Amnioinfusion aims to prevent or relieve umbilical cord compression by infusing a... (Review)
Review
BACKGROUND
Preterm rupture of membranes places a fetus at risk of cord compression and amnionitis. Amnioinfusion aims to prevent or relieve umbilical cord compression by infusing a solution into the uterine cavity.
OBJECTIVES
The objective of this review was to assess the effects of amnioinfusion for preterm rupture of membranes on maternal and perinatal outcomes.
SEARCH STRATEGY
The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched.
SELECTION CRITERIA
Randomised trials of amnioinfusion compared to no amnioinfusion in women with preterm rupture of membranes.
DATA COLLECTION AND ANALYSIS
Eligibility and trial quality were assessed by the reviewer.
MAIN RESULTS
One trial of 66 women was included. It had some methodological flaws. No significant differences between amnioinfusion and no amnioinfusion were detected for caesarean section (relative risk 0.32, 95% confidence interval 0.07 to 1.40); low Apgar scores (relative risk 0.28, 95% confidence interval 0.03 to 2.33) or neonatal death (relative risk 0.55, 95% confidence interval 0.05 to 5.77). In the amnioinfusion group, the number of severe fetal heart rate decelerations per hour during the first stage of labour were reduced (weighted mean difference -1.20, 95% confidence interval -1.83 to -0.57). These outcomes are consistent with those found in the Cochrane review on amnioinfusion for cord compression.
REVIEWER'S CONCLUSIONS
There is not enough evidence concerning the use of amnioinfusion for preterm rupture of membranes.
Topics: Amnion; Female; Fetal Membranes, Premature Rupture; Humans; Injections; Isotonic Solutions; Pregnancy; Ringer's Lactate; Sodium Chloride
PubMed: 10796224
DOI: 10.1002/14651858.CD000942