Plasma magnesium should be monitored perioperatively in patients undergoing colorectal resection

Bowel Preparation for Colonoscopy Changes Serum Composition as Detected by Thermal Liquid Biopsy and Fluorescence Spectroscopy

(1) Background: About 50% of prescribed colonoscopies report no pathological findings. A secondary screening test after fecal immunochemical test positivity (FIT+) would be required. Considering thermal liquid biopsy (TLB) as a potential secondary test, the aim of this work was to study possible interferences of colonoscopy bowel preparation on TLB outcome on a retrospective study; (2) Methods: Three groups were studied: 1/514 FIT(+) patients enrolled in a colorectal screening program (CN and CP with normal and pathological colonoscopy, respectively), with blood samples obtained just before colonoscopy and after bowel preparation; 2/55 patients from the CN group with blood sample redrawn after only standard 8-10 h fasting and no bowel preparation (CNR); and 3/55 blood donors from the biobank considered as a healthy control group; (3) Results: The results showed that from the 514 patients undergoing colonoscopy, 247 had CN and 267 had CP. TLB parameters in these two groups were similar but different from those of the blood donors. The resampled patients (with normal colonoscopy and no bowel preparation) had similar TLB parameters to those of the blood donors. TLB parameters together with fluorescence spectra and other serum indicators (albumin and C-reactive protein) confirmed the statistically significant differences between normal colonoscopy patients with and without bowel preparation; (4) Conclusions: Bowel preparation seemed to alter serum protein levels and altered TLB parameters (different from a healthy subject). The diagnostic capability of other liquid-biopsy-based methods might also be compromised. Blood extraction after bowel preparation for colonoscopy should be avoided.

Effect of Intraoperative Magnesium Sulfate Administration on Blood Glucose Control following Total Joint Arthroplasty in Patients with Diabetes

Magnesium deficiency, which is known to be highly prevalent among patients with diabetes, has been associated with insulin resistance and poor glucose control. Here, we aimed to investigate the effects of intraoperative magnesium administration on postoperative glucose control in patients with diabetes. We retrospectively reviewed the medical records of patients with type 2 diabetes who had undergone total joint arthroplasty at a tertiary hospital, where intraoperative magnesium sulfate injections were frequently performed for postoperative analgesia. The patients were grouped based on whether treated with magnesium or not (magnesium vs. control groups). We investigated postoperative blood glucose levels and sliding scale insulin requirements. After propensity matching, 170 patients were allotted to each group. Both the mean glucose level and the incidence of a mean glucose level of >200mg/dL were significantly lower in the magnesium group than in the control group (p = 0.040 and 0.013, respectively). There was also a lower insulin requirement in the magnesium group (p = 0.043). Multivariate logistic regression revealed that magnesium treatment was significantly related to a less frequent incidence of a mean blood glucose level of >200 mg/dL (p = 0.047). This study demonstrated that magnesium sulfate infusion was associated with an improved postoperative blood glucose profile in patients with diabetes.

Influence of Perioperative Serum Magnesium for Cardiac and Noncardiac Morbidity and Mortality Following Emergency Peripheral Vascular Surgery

OBJECTIVES

To examine the influence of serum magnesium on 30-day mortality and cardiac and noncardiac morbidity.

DESIGN

Retrospective cross-sectional observational study of routinely collected prospective data.

SETTING

Single-center tertiary vascular center in the United Kingdom.

PARTICIPANTS

All patients undergoing arterial peripheral vascular surgery during an unplanned admission.

INTERVENTIONS

Observational, no interventions implemented.

MEASUREMENTS AND MAIN RESULTS

In the study, n = 197. One hundred thirty-eight were male (70.1%). Median age at procedure was 70.0 years (interquartile range 20.0). Of those with a documented history, 37.9% had diabetes, 81.7% had a smoking history, 63.7% had hypertension, and 26.5% had known ischemic heart disease or heart failure. There was a significant perioperative change in magnesium (p < 0.001), calcium (p < 0.001), and creatinine (p = 0.004), with no significant alteration in potassium (p = 0.096). Thirty-day mortality was 4.6%. Thirty-day cardiac morbidity was 4.1%. Thirty-day noncardiac morbidity was 32.3%. Postoperative magnesium was independently predictive for 30-day mortality (p = 0.02, odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94-0.99) and cardiac morbidity (p = 0.03, OR 0.97, 95% CI 0.95-1.00). Only a previous smoking history was independently predictive of noncardiac morbidity (p = 0.03, OR 9.67, 95% CI 1.20-78.15).

CONCLUSION

Perioperative changes in serum magnesium may have an influence on short-term mortality and cardiac complications. This should be considered in the management of patients undergoing unplanned peripheral vascular surgery; however, further research is needed to examine the benefit of supplementation perioperatively and to explore the exact mechanisms.

Serum magnesium concentrations in patients receiving sodium picosulfate and magnesium citrate bowel preparation: an assessment of renal function and electrocardiographic conduction

BACKGROUND

We performed a post hoc analysis of two clinical trials to assess whether sodium picosulfate and magnesium (Mg(2+)) citrate (Prepopik(®) [P/MC]), a dual-action bowel preparation for colonoscopy, has an impact on serum Mg(2+) levels and cardiac electrophysiology. Although rare, hypermagnesemia has been reported in patients consuming Mg(2+)-containing cathartics, especially patients who are elderly and have renal impairment.

METHODS

Data were analyzed from two prospective, Phase III, randomized, assessor-blinded, active-control, multicenter, pivotal studies that investigated split-dose/day-before P/MC. Serum Mg(2+) and creatinine clearance (CrCl) were measured at screening, on the day of colonoscopy, and 24-48 hours, 7 days, and 4 weeks after colonoscopy; electrocardiograms also were obtained at these time points.

RESULTS

In total, 304 patients received split-dose P/MC and 294 patients received day-before P/MC. Only 10% of the patients had serum Mg(2+) above the upper limit of normal (1.05 mmol/L) on the day of colonoscopy. There was a slight inverse correlation between CrCl and Mg(2+) levels on the day of colonoscopy; however, even at the lowest CrCl, serum Mg(2+) remained below clinically significant levels of 2.0 mmol/L. Increases in serum Mg(2+) were transient, with levels returning to baseline within 24-48 hours, regardless of renal function. No patients with elevated Mg(2+) experienced a corrected QT (QTc) interval >500 milliseconds or a QTc interval increase of ≥60 milliseconds from baseline. P/MC had no impact on PR or QRS interval.

CONCLUSION

P/MC produces little impact on serum Mg(2+) levels with no clinically significant effect on cardiac conduction in patients, including those with mild-to-moderate renal impairment.

A randomized, prospective trial on efficacy and tolerability of low-volume bowel preparation methods for colonoscopy

BACKGROUND

Low-volume bowel preparations have been shown to provide an equivalent cleansing effect as that of a standard 4 L polyethylene glycol. However, studies comparing the efficacy of low-volume bowel preparations are few, and the results have been controversial. This study aimed to compare the bowel cleansing quality and tolerability between sodium picosulfate/magnesium citrate and polyethylene glycol with ascorbic acid.

METHODS

A randomized study was performed with two hundred outpatients who were prospectively enrolled. The Boston Bowel Preparation Scale and the Aronchick scale were used to evaluate the bowel cleansing quality, and bubble scoring was also performed to back up both results. To investigate patients' preferences and tolerability, a questionnaire was administered.

RESULTS

Sodium picosulfate/magnesium citrate was not inferior to polyethylene glycol with ascorbic acid in terms of successful bowel preparation (≥ 6 Boston scale score: 80% vs. 82%; p = 0.718, adequate Aronchick grade: 93% vs. 96%; p = 0.352). In addition, sodium picosulfate/magnesium citrate caused fewer gastrointestinal symptoms, and tasted better than polyethylene glycol with ascorbic acid.

CONCLUSIONS

Sodium picosulfate/magnesium citrate was not inferior to polyethylene glycol with ascorbic acid in cleansing efficacy, and was found to have higher tolerability.

The safety of osmotically acting cathartics in colonic cleansing

Efficient cleansing of the colon before a colonoscopy or a radiological examination is essential. The osmotically acting cathartics (those given the Anatomical Therapeutic Chemical code A06AD) currently used for this purpose comprise products based on three main substances: sodium phosphate, combinations of polyethylene glycol and electrolyte lavage solutions (PEG-ELS), and magnesium citrate. All these preparations give adequate cleansing results and have similar profiles in terms of the frequency and type of mild to moderate adverse effects. However, serious adverse events, such as severe hyperphosphatemia and irreversible kidney damage owing to acute phosphate nephropathy, have been reported after use of sodium-phosphate-based products. The aim of this Review is to provide an update on the potential safety issues related to the use of osmotically acting cathartics, especially disturbances of renal function and water and electrolyte balance. The available evidence indicates that PEG-ELS-based products are the safest option. Magnesium-citrate-based, hypertonic products should be administered with caution to elderly individuals and patients who are prone to develop disturbances in water and electrolyte balance. Sodium-phosphate-based products can occasionally cause irreversible kidney damage and should not be routinely used in bowel-cleansing procedures.

Sodium picosulfate/magnesium citrate: a review of its use as a colorectal cleanser

Oral sodium picosulfate/magnesium citrate (CitraFleet; Picolax), consisting of sodium picosulfate (a stimulant laxative) and magnesium citrate (an osmotic laxative), is approved for use in adults (CitraFleet; Picolax) and/or adolescents and children (Picolax) as a colorectal cleansing agent prior to any diagnostic procedure (e.g. colonoscopy or x-ray examination) requiring a clean bowel and/or surgery. It is dispensed in powder form (sodium picosulfate 0.01 g, magnesium oxide 3.5 g, citric acid 12.0 g per sachet), with the magnesium oxide and citric acid components forming magnesium citrate when the powder is dissolved in water. In adult patients, two sachets of sodium picosulfate/magnesium citrate was at least as effective and well tolerated as oral magnesium citrate 17.7 or 35.4 g, or oral polyethylene glycol 236 g in adult patients undergoing a double-contrast barium enema procedure in three large, randomized, comparative clinical studies. In contrast, sodium picosulfate/magnesium citrate was less effective than a sodium phosphate enema preparation in two studies in patients undergoing flexible sigmoidoscopy. A similar number of patients receiving two sachets of sodium picosulfate/magnesium citrate or two 45 mL doses of oral sodium phosphate the day before a double-contrast barium enema procedure achieved satisfactory barium coating and none/minimal faecal residue in one study. However, the data from three of these studies should be interpreted with caution because the administrative regimens used differed from that recommended. Sodium picosulfate/magnesium citrate is also an effective and generally well tolerated colorectal cleansing agent in children and adolescents; the preparation was more effective than oral bisacodyl 0.01 or 0.02 g plus a sodium phosphate enema preparation in this population. Further research is thus required to accurately position sodium picosulfate/magnesium citrate and fully establish its efficacy and tolerability prior to various exploratory or surgical procedures. Nevertheless, oral sodium picosulfate/magnesium citrate provides a useful option in the preparation of the colon and rectum in adults, adolescents and children undergoing any diagnostic procedure (e.g. colonoscopy or x-ray examination) requiring a clean bowel and/or surgery. Oral sodium picosulfate/magnesium citrate acts locally in the colon as both a stimulant laxative, by increasing the frequency and the force of peristalsis (sodium picosulfate component), and an osmotic laxative, by retaining fluids in the colon (magnesium citrate component), to clear the colon and rectum of faecal contents. It is not absorbed in any detectable quantities. Sodium picosulfate is a prodrug: it is hydrolyzed by bacteria in the colon to the active metabolite 4,4'-dihydroxydiphenyl-(2-pyridyl)methane. Sodium picosulfate/magnesium citrate may be associated with a dehydrating effect, as evidenced by a reduction in bodyweight and increased haemoglobin levels; some at-risk patients may experience postural hypotension and older patients may require additional electrolytes. In three large (n >100), randomized, single-blind clinical studies, two sachets of oral sodium picosulfate/magnesium citrate was at least as effective as oral magnesium citrate 17.7 or 35.4 g, or oral polyethylene glycol 236 g as a colorectal cleansing agent in adult patients undergoing a double-contrast barium enema procedure. In contrast, sodium picosulfate/magnesium citrate was less effective than a sodium phosphate enema preparation in two studies in patients undergoing flexible sigmoidoscopy. A similar number of patients receiving two sachets of sodium picosulfate/magnesium citrate or two 45 mL doses of oral sodium phosphate the day before a double-contrast barium enema procedure achieved satisfactory barium coating and none/minimal faecal residue in one study. However, the data from three of these studies should be interpreted with caution because the administrative regimens used differed from that recommended. In children and adolescents, sodium picosulfate/magnesium citrate was significantly more effective as a colorectal cleansing agent than oral bisacodyl 0.01 or 0.02 g plus a sodium phosphate enema preparation in a randomized, single-blind study; dosages were adjusted for age in this study. Oral sodium picosulfate/magnesium citrate is generally well tolerated in adult patients undergoing various investigational colorectal procedures. Adverse events were generally mild to moderate in intensity and mainly gastrointestinal in nature (e.g. abdominal cramps/pain, nausea); other common treatment-emergent adverse events included disturbance of daily activity, headache and sleep disturbance. This combination is at least as well tolerated as oral sodium phosphate or oral polyethylene glycol, with moderate/severe nausea and vomiting occurring less frequently in sodium picosulfate/magnesium citrate recipients than in those receiving oral sodium phosphate, and abdominal bloating/pain and nausea developing less often with sodium picosulfate/magnesium citrate than polyethylene glycol therapy. The incidence of abdominal pain and sleep disturbance in sodium picosulfate/magnesium citrate versus oral magnesium citrate recipients was similar in one study, but significantly lower with sodium picosulfate/magnesium citrate in another. While the incidence of most adverse events was similar in recipients of sodium picosulfate/magnesium citrate and a sodium phosphate enema preparation, more patients receiving sodium picosulfate/magnesium citrate reported moderate/severe flatulence, incontinence and sleep disturbance, and more patients receiving the enema preparation reported rectal soreness. The tolerability profile of sodium picosulfate/magnesium citrate in patients aged >70 years is reportedly similar to that in patients aged <70 years. Abdominal pain also occurred less frequently with sodium picosulfate/magnesium citrate than with oral bisacodyl plus a sodium phosphate enema preparation in children and adolescents.