The use of mannitol in cardiopulmonary bypass prime solution-Prospective randomized double-blind clinical trial

The effect of mannitol on postoperative renal function in patients undergoing coronary artery bypass surgery: A double-blinded randomized controlled trial

Introduction

Mannitol, an osmotic diuretic solution, is commonly utilized in priming cardiopulmonary bypass (CPB) and can impact kidney function. This study was conducted to investigate the impact of mannitol use during CPB on kidney function in patients undergoing coronary artery bypass surgery.

Methods

This randomized, double-blind clinical trial studied 90 patients undergoing coronary artery bypass surgery. In the control group (n=45), the prime solution included Ringer's lactate, and in the intervention group (n=45), the prime solution had 200 ml of mannitol 20% and Ringer's lactate. A P-value<0.05 was considered significant. The primary endpoint of this study is renal function.

Results

Demographic characteristics and risk factors were not significantly different between the two groups (P>0.05). Additionally, there was no statistically significant difference between two groups in terms of CPB time, aortic cross-clamp time, length of time connected to mechanical ventilation, 30-day mortality, ICU, and hospital stay time (P>0.05). Furthermore, no statistically significant difference was observed between the two groups in serum creatinine levels (P=0.53) or BUN levels (P=0.13). The study also found no statistically significant difference in the diuresis rate between the two groups (P=0.10).

Conclusion

The present study has shown that adding mannitol to the prime has no effect on kidney function, length of time connected to mechanical ventilation, length of stay in the ICU, or 30-day mortality. Therefore, it suggests that mannitol cannot be used as a preventative strategy for acute kidney injury after cardiac surgery.

Lactated Ringers, albumin and mannitol as priming during cardiopulmonary bypass reduces pulmonary edema in rats compared with hydroxyethyl starch

BACKGROUND

Endothelial disorders with edema formation and microcirculatory perfusion disturbances are common in cardiac surgery with cardiopulmonary bypass (CPB) and contribute to disturbed tissue oxygenation resulting in organ dysfunction. Albumin is protective for the endothelium and could be a useful additive to CPB circuit priming. Therefore, this study aimed to compare organ edema and microcirculatory perfusion in rats on CPB primed with lactated Ringers, albumin and mannitol (LR/albumin/mannitol) compared to 6% hydroxyethyl starch (HES).

RESULTS

Male rats were subjected to 75 min of CPB primed with either LR/albumin/mannitol or with 6% HES. Renal and lung edema were determined by wet/dry weight ratio. Pulmonary wet/dry weight ratio was lower in rats on CPB primed with LR/albumin/mannitol compared to HES (4.77 [4.44-5.25] vs. 5.33 [5.06-6.33], p = 0.032), whereas renal wet/dry weight ratio did not differ between groups (4.57 [4.41-4.75] vs. 4.51 [4.47-4.73], p = 0.813). Cremaster microcirculatory perfusion was assessed before, during and after CPB with intravital microscopy. CPB immediately impaired microcirculatory perfusion compared to baseline (LR/albumin/mannitol: 2 [1-7] vs. 14 [12-16] vessels per recording, p = 0.008; HES: 4 [2-6] vs. 12 [10-13] vessels per recording, p = 0.037), which persisted after weaning from CPB without differences between groups (LR/albumin/mannitol: 5 [1-9] vs. HES: 1 [0-4], p = 0.926). In addition, rats on CPB primed with LR/albumin/mannitol required less fluids to reach sufficient flow rates (0.5 [0.0-5.0] mL vs. 9 [4.5-10.0], p < 0.001) and phenylephrine (20 [0-40] µg vs. 90 [40-200], p = 0.004). Circulating markers for inflammation (interleukin 6 and 10), adhesion (ICAM-1), glycocalyx shedding (syndecan-1) and renal injury (NGAL) were determined by ELISA or Luminex. Circulating interleukin-6 (16 [13-25] vs. 33 [24-51] ng/mL, p = 0.006), interleukin-10 (434 [295-782] vs. 2120 [1309-3408] pg/ml, p < 0.0001), syndecan-1 (5 [3-7] vs. 15 [11-16] ng/mL, p < 0.001) and NGAL (555 [375-1078] vs. 2200 [835-3671] ng/mL, p = 0.008) were lower in rats on CPB primed with LR/albumin/mannitol compared to HES.

CONCLUSION

CPB priming with LR, albumin and mannitol resulted in less pulmonary edema, renal injury, inflammation and glycocalyx degradation compared to 6% HES. Furthermore, it enhanced hemodynamic stability compared with HES. Further research is needed to explore the specific role of albumin as a beneficial additive in CPB priming.

Effect of mannitol on postoperative delirium in patients undergoing coronary artery bypass graft: a randomised controlled trial

OBJECTIVE

Postoperative delirium (POD), especially after cardiac surgery with cardiopulmonary bypass (CPB), is a relatively common and severe complication increasing side effects, length of hospital stay, mortality and healthcare resource costs. This study aimed to determine the impact of using mannitol serum in the prime of CPB for preventing the occurrence of delirium in patients undergoing coronary artery bypass surgery.

METHODS

This study is a single-centre, double-blinded, randomised, controlled trial that was conducted from December 2022 to May 2023. Patients in the age range of 18-70 who underwent elective coronary artery bypass surgery were included in the study. In the control group (n=45), the prime solution included Ringer's lactate serum. In the intervention group (n=45), the prime solution consisted of 200 mL mannitol serum and Ringer's lactate serum. The primary outcome of the study was the incidence of POD. Secondary outcomes included the duration of mechanical ventilation, length of stay in the intensive care unit (ICU) and 30-day in-hospital mortality.

RESULTS

There were no statistically significant differences in demographic characteristics and risk factors between the control and intervention groups (p<0.05). However, the incidence of POD was significantly lower in the intervention group compared with the control group (22.25% vs 42.2%, p=0.035). There were no significant differences between the two groups regarding CPB time, aortic cross-clamp time, duration of mechanical ventilation and length of stay in ICU (p<0.05). Additionally, mortality rates and rates of return to the operating room did not differ significantly between the two groups (p<0.05).

CONCLUSIONS

This study concluded that adding mannitol to the prime of CPB pump can help reduce the incidence of delirium after cardiac surgery.

TRIAL REGISTRATION NUMBER

IRCT20221129056660N1.

Plasma hyperosmolality during cardiopulmonary bypass is a risk factor for postoperative acute kidney injury: Results from double blind randomised controlled trial

INTRODUCTION

The study objective was to investigate whether a Ringer's acetate based priming solution with addition of Mannitol and sodium concentrate increases the risk of cardiac surgery associated kidney injury (CSA-AKI).

METHODS

This is a double blind, prospective randomized controlled trial from a single tertiary teaching hospital in Sweden including patients aged ≥65 years (n = 195) admitted for routine cardiac surgery with cardiopulmonary bypass. Patients in the study group received Ringer's acetate 1000 mL + 400 mL Mannitol (60 g) + sodium chloride 40 mL (160 mmol) and heparin 2 mL (10 000 IU) 966 mOsmol (n = 98), while patients in the control group received Ringer's acetate 1400 mL + heparin 2 mL (10 000 IU), 388 mOsmol (n = 97) as pump prime. Acute kidney injury was analysed based on the Kidney Disease Improving Outcomes (KDIGO 1-3) definition.

RESULTS

The overall incidence of CSA-AKI (KDIGO stage 1) was 2.6% on day 1 in the ICU and 5.6% on day 3, postoperatively. The serum creatinine level did not show any postoperative intergroup differences, when compared to baseline preoperative values. Six patients in the Ringer and five patients in the Mannitol group developed CSA-AKI (KDIGO 1-3), all with glomerular filtration rates <60 mL/min/1.73 m2. These patients showed significantly higher plasma osmolality levels compared to preoperative values. Hyperosmolality together with patient age and the duration of the surgery were independent risk factors for postoperative acute kidney injury (KDIGO 1-3).

CONCLUSIONS

The use of a hyperosmolar prime solution did not increase the incidence of postoperative CSA-AKI in this study, while high plasma osmolality alone increased the associated risk by 30%. The data suggests further examination of plasma hyperosmolality as a relative risk factor of CSA-AKI.

Strategies for post-cardiac surgery acute kidney injury prevention: A network meta-analysis of randomized controlled trials

Objects

Cardiac surgery is associated with acute kidney injury (AKI). However, the effects of various pharmacological and non-pharmacological strategies for AKI prevention have not been thoroughly investigated, and their effectiveness in preventing AKI-related adverse outcomes has not been systematically evaluated.

Methods

Studies from PubMed, Embase, and Medline and registered trials from published through December 2021 that evaluated strategies for preventing post-cardiac surgery AKI were identified. The effectiveness of these strategies was assessed through a network meta-analysis (NMA). The secondary outcomes were prevention of dialysis-requiring AKI, mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS. The interventions were ranked using the P-score method. Confidence in the results of the NMA was assessed using the Confidence in NMA (CINeMA) framework.

Results

A total of 161 trials (involving 46,619 participants) and 53 strategies were identified. Eight pharmacological strategies {natriuretic peptides [odds ratio (OR): 0.30, 95% confidence interval (CI): 0.19-0.47], nitroprusside [OR: 0.29, 95% CI: 0.12-0.68], fenoldopam [OR: 0.36, 95% CI: 0.17-0.76], tolvaptan [OR: 0.35, 95% CI: 0.14-0.90], N-acetyl cysteine with carvedilol [OR: 0.37, 95% CI: 0.16-0.85], dexmedetomidine [OR: 0.49, 95% CI: 0.32-0.76;], levosimendan [OR: 0.56, 95% CI: 0.37-0.84], and erythropoietin [OR: 0.62, 95% CI: 0.41-0.94]} and one non-pharmacological intervention (remote ischemic preconditioning, OR: 0.76, 95% CI: 0.63-0.92) were associated with a lower incidence of post-cardiac surgery AKI with moderate to low confidence. Among these nine strategies, five (fenoldopam, erythropoietin, natriuretic peptides, levosimendan, and remote ischemic preconditioning) were associated with a shorter ICU LOS, and two (natriuretic peptides [OR: 0.30, 95% CI: 0.15-0.60] and levosimendan [OR: 0.68, 95% CI: 0.49-0.95]) were associated with a lower incidence of dialysis-requiring AKI. Natriuretic peptides were also associated with a lower risk of mortality (OR: 0.50, 95% CI: 0.29-0.86). The results of a sensitivity analysis support the robustness and effectiveness of natriuretic peptides and dexmedetomidine.

Conclusion

Nine potentially effective strategies were identified. Natriuretic peptide therapy was the most effective pharmacological strategy, and remote ischemic preconditioning was the only effective non-pharmacological strategy. Preventive strategies might also help prevent AKI-related adverse outcomes. Additional studies are required to explore the optimal dosages and protocols for potentially effective AKI prevention strategies.

Sodium Abnormalities in Cardiac Surgery With Cardiopulmonary Bypass in Adults: A Narrative Review

Perioperative sodium abnormalities or dysnatremia is not uncommon in patients presenting for cardiac surgery and is associated with increased morbidity and mortality. Both the disease process of heart failure and its treatment may contribute to abnormalities in serum sodium concentration. Serum sodium is the main determinant of serum osmolality, which in turn affects cell volume. Brain cells are particularly vulnerable to changes in serum osmolality because of the nondistensible cranium. The potentially catastrophic neurologic sequelae of rapidly correcting chronic dysnatremia and the time-sensitive nature of cardiac surgery can make the management of these patients challenging. The use of cardiopulmonary bypass to facilitate surgery adds another layer of complexity in the intraoperative management of sodium and water balance. This narrative review examines the definition and classification of dysnatremia. It also covers the etiology and pathophysiology of dysnatremia, implications during cardiac surgery requiring cardiopulmonary bypass, and the perioperative management of dysnatremia.

Mannitol Is Associated with Less Postoperative Delirium after Aortic Valve Surgery in Patients Treated with Bretschneider Cardioplegia

Background  Heart surgery with extracorporeal circulation (ECC) often leads to postoperative delirium (POD). This is associated with increased morbidity resulting in longer hospital stay and associated costs. The purpose of our study was to analyze the effect of intraoperative mannitol application on POD in patients undergoing elective aortic valve replacement (AVR).

Materials and Method s In our retrospective single-center study, 259 patients underwent elective AVR, using Bretschneider cardioplegic solution for cardiac arrest, between 2014 and 2017. Patients were divided in mannitol ( n  = 188) and nonmannitol ( n  = 71) groups. POD was assessed using the confusion assessment method for the intensive care unit (ICU). Statistical significance was assumed at p  < 0.05.

Results  Baseline patient characteristics did not differ between the groups. Incidence of POD was significantly higher in the nonmannitol group (33.8 vs. 13.8%; p  = 0.001). These patients required longer ventilation time (24.1 vs. 17.1 hours; p  = 0.021), higher reintubation rate (11.3 vs. 2.7%; p  = 0.009), ICU readmission (12.7 vs. 4.8%; p  = 0.026), prolonged ICU (112 vs. 70 hours; p  = 0.040), and hospital stay (17.8 vs. 12.6 days; p  < 0.001), leading to higher expenses (19,349 € vs. 16,606 €, p  < 0.001). A 30-day mortality was not affected, but nonmannitol group showed higher Simplified Acute Physiology Score II score (32.2 vs. 28.7; p  < 0.001). Mannitol substitution was independently associated with lower incidence of POD (odds ratio: 0.40; 95% confidence interval: 0.18–0.89; p  = 0.02).

Conclusion  Treatment with mannitol during ECC was associated with decreased incidence of POD. This was accompanied by shorter ventilation time, ICU and hospital stay, and lower treatment expenses.

The use of mannitol in cardiopulmonary bypass prime solution-Prospective randomized double-blind clinical trial

BACKGROUND

The optimal prime solution for the cardiopulmonary bypass (CPB) circuit in adult cardiac surgery has not yet been defined. Mannitol is widely used in the priming solution for CPB despite the fact that there is no clear consensus on the role of mannitol in cardiac surgery. The aim of this study was to investigate the effect of mannitol in the CPB prime solution.

METHODS

This prospective, randomized, double-blind study included 40 patients with normal cardiac and renal functions, who underwent coronary artery bypass grafting. One group received a prime based on Ringer's acetate (n = 20), and the other a prime consisting of Ringer's acetate with 200 mL mannitol (n = 20). Changes in osmolality, acid-base status, electrolytes, and renal-related parameters were monitored.

RESULTS

No significant differences were found in osmolality between the Ringer's acetate group and the mannitol group at any time. The mannitol group showed a pronounced decrease in sodium, from 138.7 ± 2.8 mmol/L at anaesthesia onset, to 133.9 ± 2.6 mmol/L after the start of CPB (P < .001). No differences were seen in the renal parameters between the groups, apart from a short-term effect of mannitol on peroperative urine production (P = .003).

CONCLUSION

We observed no effects on osmolality of a prime solution containing mannitol compared to Ringer's acetate-based prime in patients with normal cardiac and renal function. The use of mannitol in the prime resulted in a short-term, significant decrease in sodium level.