Severe electrolyte disorders following cardiac surgery: a prospective controlled observational study

Impact of maintaining serum potassium concentration ≥ 3.6mEq/L versus ≥ 4.5mEq/L for 120 hours after isolated coronary artery bypass graft surgery on incidence of new onset atrial fibrillation: Protocol for a randomized non-inferiority trial

BACKGROUND

Atrial Fibrillation After Cardiac Surgery (AFACS) occurs in about one in three patients following Coronary Artery Bypass Grafting (CABG). It is associated with increased short- and long-term morbidity, mortality and costs. To reduce AFACS incidence, efforts are often made to maintain serum potassium in the high-normal range (≥ 4.5mEq/L). However, there is no evidence that this strategy is efficacious. Furthermore, the approach is costly, often unpleasant for patients, and risks causing harm. We describe the protocol of a planned randomized non-inferiority trial to investigate the impact of intervening to maintain serum potassium ≥ 3.6 mEq/L vs ≥ 4.5 mEq/L on incidence of new-onset AFACS after isolated elective CABG.

METHODS

Patients undergoing isolated CABG at sites in the UK and Germany will be recruited, randomized 1:1 and stratified by site to protocols maintaining serum potassium at either ≥ 3.6 mEq/L or ≥ 4.5 mEq/L. Participants will not be blind to treatment allocation. The primary endpoint is AFACS, defined as an episode of atrial fibrillation, flutter or tachycardia lasting ≥ 30 seconds until hour 120 after surgery, which is both clinically detected and electrocardiographically confirmed. Assuming a 35% incidence of AFACS in the 'tight control group', and allowing for a 10% loss to follow-up, 1684 participants are required to provide 90% certainty that the upper limit of a one-sided 97.5% confidence interval (CI) will exclude a > 10% difference in favour of tight potassium control. Secondary endpoints include mortality, use of hospital resources and incidence of dysrhythmias not meeting the primary endpoint (detected using continuous heart rhythm monitoring).

DISCUSSION

The Tight K Trial will assess whether a protocol to maintain serum potassium ≥ 3.6 mEq/L is non inferior to maintaining serum potassium ≥ 4.5 mEq/L in preventing new-onset AFACS after isolated CABG.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04053816. Registered on 13 August 2019. Last update 7 January 2021.

Postoperative hypernatremia is associated with worse brain injuries on EEG and MRI following pediatric cardiac surgery

Objectives

Dysnatremia is a common electrolyte disturbance after cardiopulmonary bypass (CPB) surgery for congenital heart disease (CHD) and a known risk factor for adverse neurological events and clinical outcomes. The objective of this study was to evaluate the association of dysnatremia with worse abnormal EEG patterns, brain injuries detected by magnetic resonance imaging (MRI) and early adverse outcomes.

Methods

We monitored continuous EEG in 340 children during the initial 48 h following cardiac surgery. Demographics and clinical characteristics were recorded. Sodium concentrations were measured in the arterial blood gas analysis every 6 h. Hyponatremia and hypernatremia were classified by the average of sodium concentrations over 48 h. Postoperative cerebral MRI was performed before hospital discharge.

Results

In our patient cohort, dysnatremia was present in 46 (13.5%) patients. Among them, hyponatremia occurred in 21 (6.2%) and hypernatremia in 25 (7.4%). When compared to patients with normonatremia, hyponatremia was not associated with EEG abnormalities and early adverse outcomes (Ps ≥ .14). In hypernatremia group, the CPB time was significantly longer and more frequent use of DHCA (Ps ≤ .049). After adjusting for time, CPB time and the use of DHCA, hypernatremia was significantly associated with worse EEG abnormalities (including background, seizures and pathological delta brushes), more severe brain injuries on MRI (Ps ≤ .04) and trended to be associated with longer postoperative mechanical ventilation time (P = .06).

Conclusion

Hypernatremia and hyponatremia were common in children after cardiac surgery. Hypernatremia, but not hyponatremia, was significantly associated with worse EEG abnormalities and more severe brain injuries on MRI and extended postoperative mechanical ventilation time.

Postoperative Cardiac Arrhythmias in Pediatric and Neonatal Patients with Congenital Heart Disease-A Narrative Review

Cardiac arrhythmias are a frequent complication in the evolution of patients with congenital heart disease. Corrective surgery for these malformations is an additional predisposition to the appearance of arrhythmias. Several factors related to the patient, as well as to the therapeutic management, are involved in the etiopathogenesis of cardiac arrhythmias occurring post-operatively. The risk of arrhythmias in the immediate postoperative period is correlated with the patient's young age and low weight at surgery. The change in heart geometry, hemodynamic stress, and post-surgical scars represent the main etiopathogenic factors that can contribute to the occurrence of cardiac arrhythmias in the population of patients with operated-on congenital heart malformations. Clinical manifestations differ depending on the duration of the arrhythmia, underlying structural defects, hemodynamic conditions, and comorbidities. The accurate diagnosis and the establishment of specific management options strongly influence the morbidity and mortality associated with arrhythmias. As such, identifying the risk factors for the occurrence of cardiac arrhythmias in the case of each patient is essential to establish a specific follow-up and management plan to improve the life expectancy and quality of life of children.

Analysis of serum calcium change trajectories and prognostic factors in patients with acute type A aortic dissection

OBJECTIVES

This study aimed to analyze the correlation between serum calcium changes and short-term prognosis of patients with acute type A aortic dissection.

METHODS

Patients who underwent acute type A aortic dissection surgery at Fujian Heart Medical Center between June 2019 and June 2021 were retrospectively analyzed.

RESULTS

A total of 383 patients were enrolled. According to the changing track of serum calcium in patients after acute type A aortic dissection, three potential category tracks were determined: high-level (n = 85), medium-level (n = 259), and continuous low-level groups (n = 39). Using the medium-level group as the control, regression analysis showed that poor prognosis risk was increased in the group with continuous low serum calcium (odds ratio = 2.454, P < 0.05) and in the group with continuous low serum calcium > 48 h (odds ratio = 3.595, P < 0.05). Age (odds ratio = 1.063, P < 0.001), body mass index (odds ratio = 1.138, P < 0.05), hypertension (odds ratio = 3.697, P < 0.05), and the highest lactic acid within 72 h after surgery(odds ratio = 1.093, P < 0.05) were independent risk factors for poor prognosis after aortic dissection.

CONCLUSION

Continuous low serum calcium was an independent predictor of poor prognosis in patients with acute type A aortic dissection.

Postoperative free water administration is associated with dysnatremia after congenital heart disease surgery in infants

Dysnatremia after congenital heart disease (CHD) surgery is common. European guidelines on intraoperative fluid therapy in children recommend isotonic solutions to avoid hyponatremia, but prolonged cardiopulmonary bypass and administration of high sodium-containing solutions (i.e., blood products and sodium bicarbonate) are associated with postoperative hypernatremia. The aim of the study was to describe fluid composition prior to and during the development of postoperative dysnatremia. A retrospective observational, single-center study including infants undergoing CHD surgery. Demographics and clinical characteristics were registered. Highest and lowest plasma sodium values were recorded and associations with perioperative fluid administration, blood products, crystalloids, and colloids were explored in relation to three perioperative periods. Postoperative dysnatremia occurred in nearly 50% of infants within 48 h after surgery. Hypernatremia was mainly associated with administration of blood products (median [IQR]: 50.5 [28.4-95.5] vs. 34.5 [18.5-61.1] mL/kg; p = 0.001), and lower free water load (1.6 [1.1-2.2] mL/kg/h; p = 0.01). Hyponatremia was associated with a higher free water load (2.3 [1.7-3.3] vs. 1.8 [1.4-2.5] mL/kg/h; p = 0.001) and positive fluid balance. On postoperative day 1, hyponatremia was associated with higher volumes of free water (2.0 [1.5-2.8] vs. 1.3 [1.1-1.8] mL/kg/h; p < 0.001) and human albumin, despite a larger diuresis and more negative daily fluid balance. Postoperative hyponatremia occurred in 30% of infants despite restrictive volumes of hypotonic maintenance fluid, whereas hypernatremia was mainly associated with blood product transfusion. Individualized fluid therapy, with continuous reassessment to reduce the occurrence of postoperative dysnatremia is mandatory in pediatric cardiac surgery. Prospective studies to evaluate fluid therapy in pediatric cardiac surgery patients are warranted.

Aortic Peak Flow Velocity As a Predictor of Fluid Responsiveness in Mechanically Ventilated Children: A Systematic Review and Meta-Analysis

OBJECTIVES

This meta-analysis aimed to determine the accuracy of the respiratory variations in aortic peak flow velocity (delta Vpeak) in predicting fluid responsiveness and the moderators of that accuracy.

DATA SOURCES

We performed searches for studies that used delta Vpeak as a predictor of fluid responsiveness in mechanically ventilated children in PubMed, Embase, Scopus, and CINAHL from inception to June 20, 2022.

STUDY SELECTION AND DATA EXTRACTION

Fifteen studies ( n = 452) were included in this meta-analysis. The diagnostic test data of the included studies were synthesized as pooled sensitivity, specificity, and diagnostic odds ratio (DOR) and the area under the curve (AUC) of the summary receiver operating characteristic of delta Vpeak.

DATA SYNTHESIS

The delta Vpeak cutoff values applied in these studies had a median of 12.3% (interquartile range, 11.50-13.25%). The pooled sensitivity and specificity of delta Vpeak were 0.80 (95% CI, 0.71-0.87) and 0.82 (95% CI, 0.75-0.87), respectively. The DOR of delta Vpeak was 23.41 (95% CI, 11.61-47.20). The AUC of delta Vpeak was 0.87. Subgroup analyses revealed that the accuracy of delta Vpeak was not moderated by ventilator settings, measures of delta Vpeak, gold standard index, the cutoff gold standard value of responders, type and volume of fluid, duration of fluid challenge, use of vasoactive drugs, general anesthesia, and cardiopulmonary bypass.

CONCLUSIONS

By using the cutoff of approximately 12.3%, the delta Vpeak appears to have good accuracy in predicting fluid responsiveness in mechanically ventilated children. The moderators of delta Vpeak predictability are not found.

The hypokalaemia that came from the cold

While electrolyte disorders are common in nephrologists' clinical practice, hypothermia is a condition that nephrologists rarely encounter. Hypothermia can induce several pathophysiological effects on the human body, including hypokalaemia, which is reversible with rewarming. Despite growing evidence from animal research and human studies, the underlying mechanisms of hypothermia-induced hypokalaemia remain unclear. Boubes and colleagues recently presented a case series of hypokalaemia during hypothermia and rewarming, proposing a novel hypothesis for the underlying mechanisms. In this editorial, we review the current knowledge about hypothermia and associated electrolyte changes with insights into the effects of hypothermia on renal physiology.

Calcium use during paediatric in-hospital cardiac arrest is associated with worse outcomes

AIM

To evaluate associations between calcium administration and outcomes among children with in-hospital cardiac arrest and among specific subgroups in which calcium use is hypothesized to provide clinical benefit.

METHODS

This is a secondary analysis of observational data collected prospectively as part of the ICU-RESUScitation project. Children 37 weeks post-conceptual age to 18 years who received chest compressions in one of 18 intensive care units from October 2016-March 2021 were eligible. Data included child and event characteristics, pre-arrest laboratory values, pre- and intra-arrest haemodynamics, and outcomes. Outcomes included sustained return of spontaneous circulation (ROSC), survival to hospital discharge, and survival to hospital discharge with favourable neurologic outcome. A propensity score weighted cohort was used to evaluate associations between calcium use and outcomes. Subgroups included neonates, and children with hyperkalaemia, sepsis, renal insufficiency, cardiac surgery with cardiopulmonary bypass, and calcium-avid cardiac diagnoses.

RESULTS

Of 1,100 in-hospital cardiac arrests, median age was 0.63 years (IQR 0.19, 3.81); 450 (41%) received calcium. Among the weighted cohort, calcium use was not associated with sustained ROSC (aOR, 0.87; CI95 0.61-1.24; p = 0.445), but was associated with lower rates of both survival to hospital discharge (aOR, 0.68; CI95 0.52-0.89; p = 0.005) and survival with favourable neurologic outcome at hospital discharge (aOR, 0.75; CI95 0.57-0.98; p = 0.038). Among subgroups, calcium use was associated with lower rates of survival to hospital discharge in children with sepsis and renal insufficiency.

CONCLUSIONS

Calcium use was common during paediatric in-hospital cardiac arrest and associated with worse outcomes at hospital discharge.

Ectopic Atrial Tachycardia in Infants Following Congenital Heart Disease Surgery

Although ectopic atrial tachycardia (EAT) is common following surgery for congenital heart disease (CHD), there are limited data regarding this arrhythmia. This study assessed risk factors and outcomes for patients less than one year of age with post-operative EAT. This was a retrospective analysis of infants undergoing CHD surgery from 2007 to 2020. Patients and surgeries with EAT were compared to controls without EAT. Out of 5372 infant CHD surgeries, EAT developed in 129 (2.5%). Compared to controls, the EAT cohort was younger (median 7 vs 85 days, p < 0.01), weighed less at time of surgery (3.3 vs 4.2 kg, p < 0.01), and was more likely to have DiGeorge syndrome (7.7% vs 3.0%, p < 0.01). Multivariate analysis revealed total anomalous venous connection (TAPVC) repair (odds ratio [OR] 2.8; 95% confidence interval 1.5-5.2), DiGeorge syndrome (OR 2.4; 1.1-5.2), Society of Thoracic Surgeons-European Association for Cardio-Thoracic surgery (STAT) category ≥ 4 (OR 2.1; 1.0-4.4), and longer cardiopulmonary bypass times (OR 1.1; 1.0-1.2) as independent risk factors for EAT. The onset of EAT occurred a median of 9 days (IQR 5-14 days) after CHD surgery. Antiarrhythmic treatment was initiated in 109/129 patients (84%) with propranolol (71%) and amiodarone (24%) the most commonly used medications. Although 15 (11.6%) patients did not survive to hospital discharge, EAT was not directly implicated in any deaths. EAT occurred after 2.5% of infant CHD surgeries. In addition to TAPVC repair, longer and more complex surgeries were associated with an increased the risk for the development of post-operative EAT.

Calcium Administration During Cardiopulmonary Resuscitation for In-Hospital Cardiac Arrest in Children With Heart Disease Is Associated With Worse Survival-A Report From the American Heart Association's Get With The Guidelines-Resuscitation (GWTG-R) Registry

OBJECTIVES

IV calcium administration during cardiopulmonary resuscitation (CPR) for pediatric in-hospital cardiac arrest (IHCA) is associated with worse survival. We evaluated survival to hospital discharge in children with heart disease (HD), where calcium is more frequently administered during CPR.

DESIGN

Retrospective study of a multicenter registry database.

SETTING

Data reported to the American Heart Association's (AHA) Get With The Guidelines-Resuscitation registry.

PATIENTS

Children younger than 18 years with HD experiencing an index IHCA event requiring CPR between January 2000 and January 2019. Using propensity score matching (PSM), we selected matched cohorts of children receiving and not receiving IV calcium during CPR and compared the primary outcome of survival to hospital discharge.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 4,556 children with HD experiencing IHCA. Calcium was administered in 1,986 (44%), more frequently in children younger than 1 year old (65% vs 35%; p < 0.001) and surgical cardiac (SC) compared with medical cardiac patients (51% vs 36%; p < 0.001). Calcium administration during CPR was associated with longer duration CPR (median 27 min [interquartile range (IQR): 10-50 min] vs 5 min [IQR, 2-16 min]; p < 0.001) and more frequent extracorporeal-CPR deployment (25% vs 8%; p < 0.001). In the PSM cohort, those receiving calcium had decreased survival to hospital discharge (39% vs 46%; p = 0.02) compared with those not receiving calcium. In a subgroup analysis, decreased discharge survival was only seen in SC cohorts.

CONCLUSIONS

Calcium administration during CPR for children with HD experiencing IHCA is common and is associated with worse survival. Administration of calcium during CPR in children with HD should be restricted to specific indications as recommended by the AHA CPR guidelines.

Sellke F, Feng J. Potassium and Cardiac Surgery

Potassium homeostasis affects cardiac rhythm and contractility, along with vascular reactivity and vascular smooth muscle proliferation. This chapter will focus on potassium dynamics during and after cardiac surgery involving cardioplegic arrest and cardiopulmonary bypass (CPB). Hyperkalemic, hypothermic solutions are frequently used to induce cardioplegic arrest and protect the heart during cardiac surgery involving CPB. Common consequences of hyperkalemic cardioplegic arrest and reperfusion include microvascular dysfunction involving several organ systems and myocardial dysfunction. Immediately after CPB, blood potassium levels often drop precipitously due to a variety of factors, including CPB -induced electrolyte depletion and frequent, long-term administration of insulin during and after surgery. Meanwhile, some patients with pre-existing kidney dysfunction may experience postoperative hyperkalemia following cardioplegia. Any degree of postoperative hyper/hypokalemia significantly elevates the risk of cardiac arrythmias and subsequent myocardial failure. Therefore, proper management of blood potassium levels during and after cardioplegia/CPB is crucial for optimizing patient outcomes following cardiac surgery.

Development and Validation of a Personalized Model With Transfer Learning for Acute Kidney Injury Risk Estimation Using Electronic Health Records

IMPORTANCE

Acute kidney injury (AKI) is a heterogeneous syndrome prevalent among hospitalized patients. Personalized risk estimation and risk factor identification may allow effective intervention and improved outcomes.

OBJECTIVE

To develop and validate personalized AKI risk estimation models using electronic health records (EHRs), examine whether personalized models were beneficial in comparison with global and subgroup models, and assess the heterogeneity of risk factors and their outcomes in different subpopulations.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study analyzed EHR data from 1 tertiary care hospital and used machine learning and logistic regression to develop and validate global, subgroup, and personalized risk estimation models. Transfer learning was implemented to enhance the personalized model. Predictor outcomes across subpopulations were analyzed, and metaregression was used to explore predictor interactions. Adults who were hospitalized for 2 or more days from November 1, 2007, to December 31, 2016, were included in the analysis. Patients with moderate or severe kidney dysfunction at admission were excluded. Data were analyzed between August 28, 2019, and May 8, 2022.

EXPOSURES

Clinical and laboratory variables in the EHR.

MAIN OUTCOMES AND MEASURES

The main outcome was AKI of any severity, and AKI was defined using the Kidney Disease: Improving Global Outcomes serum creatinine criteria. Performance of the models was measured with area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve, and calibration.

RESULTS

The study cohort comprised 76 957 inpatient encounters. Patients had a mean (SD) age of 55.5 (17.4) years and included 42 159 men (54.8%). The personalized model with transfer learning outperformed the global model for AKI estimation in terms of AUROC among general inpatients (0.78 [95% CI, 0.77-0.79] vs 0.76 [95% CI, 0.75-0.76]; P < .001) and across the high-risk subgroups (0.79 [95% CI, 0.78-0.80] vs 0.75 [95% CI, 0.74-0.77]; P < .001) and low-risk subgroups (0.74 [95% CI, 0.73-0.75] vs 0.71 [95% CI, 0.70-0.72]; P < .001). The AUROC improvement reached 0.13 for the high-risk subgroups, such as those undergoing liver transplant and cardiac surgery. Moreover, the personalized model with transfer learning performed better than or comparably with the best published models in well-studied AKI subgroups. Predictor outcomes varied significantly between patients, and interaction analysis uncovered modifiers of the predictor outcomes.

CONCLUSIONS AND RELEVANCE

Results of this study demonstrated that a personalized modeling with transfer learning is an improved AKI risk estimation approach that can be used across diverse patient subgroups. Risk factor heterogeneity and interactions at the individual level highlighted the need for agile, personalized care.

Admission electrolyte and osmotic pressure levels are associated with the incidence of contrast-associated acute kidney injury

This retrospective study aimed to explore the relationships between electrolytes and osmotic pressure homeostasis with contrast-associated acute kidney injury (CA-AKI) risk in patients with percutaneous coronary intervention or coronary angiography. We totally enrolled 4386 hospitalized patients, who were categorized into five groups based on the predetermined cutoff values of electrolytes and osmotic pressure. CA-AKI was defined as an increase in serum creatine by 0.5 mg/dL (44.2 mol/L) or a 25% increase of the highest level post-operation compared to baseline. Multivariable logistic analysis was used to examine the association of CA-AKI incidence with electrolytes and osmotic pressure levels. Piecewise linear regression models and restricted cubic spline analysis were further utilized to determine the nonlinear relationship. The results showed U-shaped relationships between sodium, chloride, magnesium, and osmotic pressure levels and CA-AKI incidence. The lowest incidence was observed in the categories of 139–141.9 mmol/L, 107.0–109.9 mmol/L, 0.91–1.07 mmol/L, and 290.0–299.9 mOsm/kg, respectively. J-shaped associations were observed for potassium and phosphate levels and CA-AKI incidence, with the lowest incidence in the categories of 3.50–4.09 mmol/L and 0.96–1.28 mmol/L, respectively. A negative correlation was observed between calcium level and CA-AKI incidence, with the lowest CA-AKI risk in the category of ≥ 2.58 mmol/L. In conclusion, abnormally higher or lower sodium, chloride, magnesium, phosphate, and osmotic pressure levels on admission were associated with increased risks of CA-AKI. While for potassium and calcium, the status of hyperkalemia and hypocalcemia on admission showed more susceptibility for CA-AKI.

Concentrations of Mg, Ca, Fe, Cu, Zn, P and anthropometric and biochemical parameters in adults with chronic heart failure

Background

The study investigated the relationship between the concentrations of Mg, Ca, Fe, Cu, Zn, P and anthropometric and biochemical parameters in the blood serum of patients with heart failure (HF) and the potential influence on the development and progression of HF.

Material & methods

The study included 214 patients (155 men and 59 women), aged 40–87 years, presenting symptoms or signs typical of HF (according to the NYHA functional classification). Serum concentrations were determined for Mg, Ca, Fe, Cu, Zn, P, C-reactive protein (CRP), creatinine, urea, triglyceride levels (TG), total cholesterol (CH), high density protein (HDL), low density protein (LDL). The levels of macro-and microminerals were analysed using inductively coupled serum optical emission spectrometry (ICP-OES).

Results

Our study confirmed the role of known risk factors in the development of heart failure, including: overweight, diabetes, hypertension, high triglycerides (TG), high total cholesterol (CH), high levels of low density protein (LDL) and reduced levels of high density protein (HDL), high CRP, high creatinine. Moreover, deficient serum concentrations of Mg (47% of the studied men and 54% of the women) and Cu (in 44% of men and more than 30% of women) were observed, as well as subnormal serum Fe (2% of women) and Zn (1% of men). Elevated serum Ca was found in 50% of men and 49% of women. In 44% of the studied men and 52% of the studied women, P levels in serum were also above-average. The study revealed a significant positive correlation between serum levels of Ca and Mg, and also Ca and Cu in women. In men, serum Cu was positively correlated with Mg and Ca concentrations. In patients from group 1 (NYHA I–II), Mg content was positively correlated with Ca and Cu. In this patient group, Ca was also positively associated with Cu content in serum. In group 2 (NYHA III-IV), serum Mg concentration was significantly positively correlated with that of Cu and Ca.

Conclusions

Changes in the serum concentrations of macro-and microminerals may significantly affect the severity of HF in Polish patients.

In Vitro and In Vivo Comparison of Hemoglobin and Electrolytes Following the Collection of Cell Saver Blood Washed with Either Normal Saline or Plasma-Lyte A

Cell saver blood is typically washed with normal saline (NS); however, recent studies have reported decreased red blood cell hemolysis and increased platelet function when a more physiologic washing solution, such as Plasma-Lyte A (PL-A) is used. We evaluated the in vitro and in vivo effects of NS compared to PL-A as washing solutions for cell saver blood in pediatric cardiac surgery. Cell saver blood was re-infused for up to 24 hours post-collection. Laboratory and clinical data were collected from infants receiving cell saver washed with either NS (n = 20) or PL-A (n = 21). Compositions of the cell saver blood were compared between groups at 5 in vitro time points and in vivo patient blood at 24 hours post-bypass. Although there were differences in in vitro laboratory values between groups; 24 hours post-bypass, in vivo results were similar. Our data supports 24-hour reinfusion of cell saver washed with either NS versus PL-A in pediatric cardiac surgery patients, and provides data on the differences in cell saver composition to guide future studies.

Hyperchloremia is associated with poor renal outcome after coronary artery bypass grafting

Background

Hyperchloremia is associated with the risks of several morbidities and mortality. However, its relationship with acute kidney injury (AKI) and end-stage renal disease (ESRD) in patients undergoing coronary artery bypass grafting (CABG) remains unresolved.

Methods

A total of 2977 patients undergoing CABG between 2003 and 2015 were retrospectively reviewed from two tertiary hospitals. Patients were categorized by serum chloride levels into normochloremia (95–105 mmol/L), mild hyperchloremia (106–110 mmol/L), and severe hyperchloremia (> 110 mmol/L). The odds ratios (ORs) for AKI and hazard ratios (HRs) for ESRD were calculated after adjustment for multiple covariates. The death-adjusted risk of ESRD was additionally evaluated.

Results

Postoperative AKI occurred in 798 patients (26.5%). The hyperchloremia group had a higher risk of AKI than the normochloremia group, wherein the risk was incremental depending on the severity of hyperchloremia, as follows: ORs were 1.26 (1.06–1.51) and 1.95 (1.52–2.51) in the mild and severe hyperchloremia groups, respectively. During a median period of 7 years (maximum 15 years), 70 patients (2.3%) had ESRD. The severe hyperchloremia group was at an elevated risk of ESRD compared with the normochloremia group, with an HR of 2.43 (1.28–4.63). Even after adjusting for the competing risk of death, hyperchloremia was associated with the risk of ESRD.

Conclusions

Preoperative hyperchloremia is associated with poor renal outcomes such as AKI and ESRD after CABG. Accordingly, serum chloride should be monitored in patients undergoing CABG.

Examination of Electrolyte Replacements in the ICU Utilizing MIMIC-III Dataset Demonstrates Redundant Replacement Patterns

Electrolyte repletion in the ICU is one of the most ubiquitous tasks in critical care, involving significant resources while having an unclear risk/benefit ratio. Prior data indicate most replacements are administered while electrolytes are within or above reference ranges with little effect on serum post-replacement levels and potential harm. ICU electrolyte replacement patterns were analyzed using the MIMIC-III database to determine the threshold governing replacement decisions and their efficiency. The data of serum values for potassium, magnesium, and phosphate before and after repletion events were evaluated. Thresholds for when repletion was administered and temporal patterns in the repletion behaviors of ICU healthcare providers were identified. Most electrolyte replacements happened when levels were below or within reference ranges. Of the lab orders placed, a minuscule number of them were followed by repletion. Electrolyte repletion resulted in negligible (phosphate), small (potassium), and modest (magnesium) post-replacement changes in electrolyte serum levels. The repletion pattern followed hospital routine work and was anchored around shift changes. A subset of providers conducting over-repletion in the absence of clinical indication was also identified. This pattern of behavior found in this study supports previous studies and may allude to a universal pattern of over-repletion in the ICU setting.

Balanced forced-diuresis as a renal protective approach in cardiac surgery: Secondary outcomes of electrolyte changes

Objectives

Forced‐diuresis during cardiopulmonary bypass (CPB) can be associated with significant electrolyte shifts. This study reports on the serum electrolyte changes during balanced forced‐diuresis with the RenalGuard® system (RG) during CPB.

Methods

Patients at risk of acute kidney injury (AKI)—(history of diabetes &/or anaemia, e‐GFR 20–60 ml/min/1.73 m², anticipated CPB time >120 min, Log EuroScore >5)—were randomized to either RG (study group) or managed as per current practice (control group).

Results

The use of RG reduced AKI rate (10% for RG and 20.9% in control, p = .03). Mean urine output was significantly higher in the RG group during surgery (2366 ± 877 ml vs. 765 ± 549 ml, p < .001). The serum potassium levels were maintained between 3.96 and 4.97 mmol/L for the RG group and 4.02 and 5.23 mmol/L for the controls. Median potassium supplemental dose was 60 (0–220) mmol (RG group) as compared to 30 (0–190) mmol for control group over first 24 h (p < .001). On Day 1 post‐op, there were no significant differences in the serum sodium, potassium, calcium, magnesium, phosphate, and chloride levels between the two groups. Otherwise, postoperative clinical recovery was also similar.

Conclusions

Balanced forced‐diuresis with the RG reduced AKI rates after on‐pump cardiac surgery compared to controls. Although the RG group required higher doses of IV potassium replacement in the postoperative period, normal serum levels of potassium were maintained by appropriate intravenous potassium supplementation and the clinical outcomes between groups were similar.

Critical arrhythmia in postoperative cardiac children: Recognition and management

Arrhythmias after pediatric cardiac surgery are common and can be life-threatening. They occur intraoperatively or may appear shortly after surgery during postoperative care. They require early management and specific intervention. In this review, we describe important critical arrhythmias that are encountered during postoperative management of children undergoing cardiac surgery. We review the diagnosis, management, and explain the role of epicardial electrocardiogram in diagnosing certain types of postoperative rhythm abnormalities seen during early period after pediatric cardiac surgery.

Maintenance of Serum Potassium Levels ≥3.6 mEq/L Versus ≥4.5 mEq/L After Isolated Elective Coronary Artery Bypass Grafting and the Incidence of New-Onset Atrial Fibrillation: Pilot and Feasibility Study Results

OBJECTIVE

Serum potassium levels frequently are maintained at high levels (≥4.5 mEq/L) to prevent atrial fibrillation after cardiac surgery (AFACS), with limited evidence. Before undertaking a noninferiority randomized controlled trial to investigate the noninferiority of maintaining levels ≥3.6 mEq/L compared with this strategy, the authors wanted to assess the feasibility, acceptability, and safety of recruiting for such a trial.

DESIGN

Pilot and feasibility study of full trial protocol.

SETTING

Two university tertiary-care hospitals.

PARTICIPANTS

A total of 160 individuals undergoing first-time elective isolated coronary artery bypass grafting.

INTERVENTIONS

Randomization (1:1) to protocols aiming to maintain serum potassium at either ≥3.6 mEq/L or ≥4.5 mEq/L after arrival in the postoperative care facility and for 120 hours or until discharge from the hospital or AFACS occurred, whichever happened first.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes: (1) whether it was possible to recruit and randomize 160 patients for six months (estimated 20% of those eligible); (2) maintaining supplementation protocol violation rate ≤10% (defined as potassium supplementation being inappropriately administered or withheld according to treatment allocation after a serum potassium measurement); and (3) retaining 28-day follow-up rates ≥90% after surgery. Between August 2017 and April 2018, 723 patients were screened and 160 (22%) were recruited. Potassium protocol violation rate = 9.8%. Follow-up rate at 28 days = 94.3%. Data on planned outcomes for the full trial also were collected.

CONCLUSIONS

It is feasible to recruit and randomize patients to a study assessing the impact of maintaining serum potassium concentrations at either ≥3.6 mEq/L or ≥4.5 mEq/L on the incidence of AFACS.

Intraoperative Cell Saving: Is the Solution the Actual Problem?

Allogenic blood is a scarce, precious, and expensive resource that is not always available on demand. After termination of cardiopulmonary bypass, a large amount of residual pump blood remains in the extracorporeal circuit. The cell saver washes and concentrates this blood with .9% normal saline (NS), making autologous blood available and reducing the demand for allogenic blood. To quantify the quality of residual pump blood it was washed with either NS or a bicarbonate-buffered solution (Balsol). A qualitative in vitro analysis was conducted. Residual cardiopulmonary bypass blood from forty bypass circuits was processed with a cell saver device, using NS or Balsol solution. Measurements made compared the pH, electrolytes, metabolites, hematocrit, hemoglobin, osmolality, albumin, total protein, and strong ion difference. There were significant differences between the NS and Balsol groups. In the Balsol group, osmolality, electrolytes, and strong ion difference were similar to the constitution of Balsol solution after washing, but not with the normal saline group. Washing residual cardiopulmonary bypass pump blood with Balsol solution results in a resuspended red cell concentrate with a superior electrolyte profile and a strong ion difference similar to that of residual pump blood.

Hypophosphatemia in critically ill adults and children - A systematic review

BACKGROUND & AIMS

Phosphate is the main intracellular anion essential for numerous biological processes. Symptoms of hypophosphatemia are non-specific, yet potentially life-threatening. This systematic review process was initiated to gain a global insight into hypophosphatemia, associated morbidity and treatments.

METHODS

A systematic review was conducted (PROSPERO CRD42020163191). Nine clinically relevant questions were generated, seven for adult and two for pediatric critically ill patients, and prevalence of hypophosphatemia was assessed in both groups. We identified trials through systematic searches of Medline, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science. Quality assessment was performed using the Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa Scale for observational studies.

RESULTS

For all research questions, we identified 2727 titles in total, assessed 399 full texts, and retained 82 full texts for evidence synthesis, with 20 of them identified for several research questions. Only 3 randomized controlled trials were identified with two of them published only in abstract form, as well as 28 prospective and 31 retrospective studies, and 20 case reports. Relevant risk of bias regarding selection and comparability was identified for most of the studies. No meta-analysis could be performed. The prevalence of hypophosphatemia varied substantially in critically ill adults and children, but no study assessed consecutive admissions to intensive care. In both critically ill adults and children, several studies report that hypophosphatemia is associated with worse outcome (prolonged length of stay and the need for respiratory support, and higher mortality). However, there was insufficient evidence regarding the optimal threshold upon which hypophosphatemia becomes critical and requires treatment. We found no studies regarding the optimal frequency of phosphate measurements, and regarding the time window to correct hypophosphatemia. In adults, nutrient restriction on top of phosphate repletion in patients with refeeding syndrome may improve survival, although evidence is weak.

CONCLUSIONS

Evidence on the definition, outcome and treatment of clinically relevant hypophosphatemia in critically ill adults and children is scarce and does not allow answering clinically relevant questions. High quality clinical research is crucial for the development of respective guidelines.

Implications of Postpancreatectomy Hypophosphatemia

BACKGROUND

Electrolyte abnormalities are commonly found after major abdominal surgery for malignancy. We hypothesized that the severity of hypophosphatemia developed in pancreatectomy patients would be associated with the incidence of complications postoperatively.

METHODS

A retrospective analysis of an institutional database was conducted for all pancreatic resections (2009-2017). Patient charts were reviewed for demographics, clinicopathologic factors, and perioperative outcomes.

RESULTS

In a cohort of 283 pancreatectomy patients, 107 (37.8%) and 134 (47.3%) developed mild (2.0-2.5 mg/dL) and moderate/severe hypophosphatemia (<2.0 mg/dL), respectively. Nadir serum phosphate levels were shown to occur on postoperative day (POD) 2 for patients without complications and POD3 for patients who had at least 1 complication. Patients who developed severe hypophosphatemia were significantly more likely to suffer fistula-related complications (P = .0401).

CONCLUSIONS

Assessing the severity and timing of postpancreatectomy hypophosphatemia presents an opportunity for early detection of impending fistula-related complications.

Electrolyte disorders are ERAS-associated in patients undergoing hepato-pancreato-biliary surgery

PURPOSE

Emerging evidences have raised concerns about electrolyte disorders caused by restrictive fluid management in the enhanced recovery after surgery (ERAS) protocol. This study aims to investigate the morbidity and treatment of electrolyte disorders associated with ERAS in patients undergoing hepato-pancreato-biliary (HPB) surgery.

METHODS

Clinical data from 157 patients under the ERAS program and 166 patients under the traditional (Non-ERAS) program after HPB surgery were retrospectively analyzed. Risk factors and predictive factors of postoperative electrolyte disorders were analyzed by logistic regression analysis and receiver operator characteristic (ROC) curve analysis, respectively.

RESULTS

The average of intravenous fluid, sodium, chloride, and potassium supplementation after surgery were significantly lower in the ERAS group. Hypokalemia was the most common type of electrolyte disorders in the ERAS group, whose incidence was substantially increased compared to that in the Non-ERAS group [28.77% vs. 8.97%, p < 0.001, on postoperative (POD) 5]. Logistic regression analysis identified the ERAS program and age as independent risk factors of hypokalemia. ROC curve analysis identified serum potassium levels below 3.76 mmol/L on POD 3 (area under curve 0.731, sensitivity 58.54%, specificity 82.69%) as a predictive factor for postoperative hypokalemia in ERAS patients. Oral supplementation at an average of 35.41 mmol potassium per day was effective in restoring the ERAS-associated hypokalemia.

CONCLUSIONS

ERAS procedures were particularly associated with a lower supplementation of potassium and a higher incidence of hypokalemia in patients after HPB surgery. Oral potassium supplementation could be an adopted ERAS program for the elderly undergoing HPB surgery.

Impact of Custodiol-N cardioplegia on acute kidney injury after cardiopulmonary bypass

Myocardial protection during cardiopulmonary bypass (CPB) can be achieved using cardioplegic solutions. Although, acute kidney injury (AKI) is a common complication following CPB, the effects of cardioplegic solutions on AKI have rarely been investigated. Within this study, the effects of the cardioplegic solutions histidine-tryptophan-ketoglutarate (HTK; Custodiol) and HTK-N (Custodiol-N) on AKI in a large animal model were compared. Therefore, Landrace pigs underwent median sternotomy, CPB at 34°C, 90 minutes of cardiac arrest and 120 minutes of reperfusion. Animals were randomized for single-shot cardioplegia with either HTK (n = 10) or HTK-N (n = 10). Renal biopsies and sera were analyzed to determine AKI biomarkers and apoptosis. Compared to HTK, HTK-N induced a decreased extent of proximal tubule swelling (48.3 ± 1.6 µm vs 52.3 ± 1.1 µm, P = .05) and decreased cytochrome c release (0.26 ± 0.04 vs 0.46 ± 0.08, P = .04) without reaching statistical significance due to Bonferroni correction. Comparing baseline and postreperfusion levels, the hemoglobin (Hb) and blood calcium levels were lower in HTK-N (Hb_baseline : 6.0 ± 0.6 mmol/L, Hb_reperfusion : 6.2 ± 0.7 mmol/L, P = .12; Ca²⁺ _baseline : 1.36 ± 0.05 mmol/L, Ca²⁺ _reperfusion : 1.28 ± 0.05 mmol/L, P = .16) compared to the HTK group (Hb_baseline : 5.9 ± 0.4 mmol/L, Hb_reperfusion : 4.7 ± 0.8 mmol/L, P < .01; Ca²⁺ _baseline : 1.34 ± 0.07 mmol/L, Ca²⁺ _reperfusion : 1.24 ± 0.06 mmol/L, P < .01). The present study showed that HTK-N could positively affect the kidney during CPB. Hb and calcium levels were stabilized. A statistical trend was found showing that AKI-related proximal tubule swelling and cytochrome c release were diminished.

The perioperative effect of magnesium sulfate in patients with concentric left ventricular hypertrophy undergoing cardiac surgery: A double-blinded randomized study

Objective:

The objective of this study was to assess the cardioprotective effect of magnesium sulfate in patients with left ventricular concentric hypertrophy undergoing cardiac surgery.

Design:

The study was a double-blinded randomized study.

Setting:

This study was conducted at a cardiac center.

Patients:

The study included 250 patients.

Intervention:

The study included two groups (each = 125): Group M – the patients who received magnesium sulfate infusion (15 mg/kg/h). The infusion was started 20 min before induction, during surgery, and the first postoperative 24 h. Group C – the patients who received an equal amount of normal saline.

Measurements:

The variables included troponin I level, creatinine kinase-MB (CK-MB) level, electrocardiograph (ECG) with automatic ST-segment analysis (leads II and V), E/A peak ratio, end-diastolic volume, cardiac index (CI), heart rate, mean arterial blood pressure (MAP), mean arterial pulmonary pressure (mPAP), pulmonary and systemic vascular resistances, and pharmacological and mechanical support.

Main Results:

The troponin I level, CK-MB, and ECG changes were lower in Group M than Group C (P < 0.05). The E/A peak ratio and end-diastolic volume increased in Group M than Group C (P < 0.05). There was a significant increase in the CI and a decrease in the heart rate, mPAP, pulmonary vascular resistances, and pharmacological and mechanical support in Group M compared to Group C (P < 0.05). There were minimal changes in the MAP and systemic vascular resistance in Group M compared to Group C (P < 0.05).

Conclusion:

The magnesium sulfate provides a cardioprotective effect in patients with concentric ventricular hypertrophy undergoing cardiac surgery. It decreases the incidence of perioperative myocardial infarction and arrhythmia. Furthermore, it decreases the requirement of pharmacological and mechanical support.

Hypomagnesaemia and other electrolytes imbalances in open and closed pediatrics cardiac surgery

Objective and Background:

During the past decade, many researchers have indicated that open cardiac surgery, using cardiopulmonary bypass, could be an essential factor to induce post-operative electrolyte imbalances which may be followed by life threatening complications such as arrhythmia. Nevertheless, by this time there may be a few researches about comparing of hypomagnesaemia and other electrolyte imbalances between open, on pump, and closed, off pump, heart operation.

Methods:

In this cohort study conducted at Rajaie Heart Center in Tehran from December 2014 to August 2015, we evaluated hypomagnesaemia, hypocalcemia, hypokalemia and hyponatremia in 205 children aged under 15 years who underwent open (101 children) and closed (104 children) cardiac surgery. Repeated measures ANOVA, paired t test and Chi-square/Fisher exact test were used for analysis the data in SPSS version 21.

Results:

According to our study the frequency of electrolyte imbalances including hypomagnesaemia after pediatric heart surgery is relatively high (28.7% hypomagnesaemia at the second day) with more occurrence in closed cardiac operations. There was no significant relationship between hypomagnesaemia and pump time duration (P>0.05). On the other hand, this research indicated that there is significant relationship between post-operative hypomagnesaemia and some other variables including cyanotic heart disease (P=0.01) and concurrent electrolyte imbalance such as hypocalcaemia and hypokalemia (P<0.05).

Conclusion:

Early evaluation and correction of hypomagnesaemia should be considered after both closed and open heart operation.

New-Onset Atrial Fibrillation in Adult Patients After Cardiac Surgery

Purpose of Review

An overview of recent literature regarding pathophysiology, risk factors, prophylaxis, and treatment of new-onset atrial fibrillation (AF) in post-cardiac surgical patients.

Recent Findings

AF is the most frequent adverse event after cardiac surgery with significant associated morbidity, mortality, and financial cost. Its causes are multifactorial, and models to stratify patients into risk categories are progressing but a consistent, evidence-based system has not yet been developed. Pharmacologic and surgical interventions to prevent and treat this complication have been an area of ongoing research and recent societal guidelines reflect this.

Summary

Inconsistencies remain surrounding how to best identify higher-risk AF patients, which interventions should be used to prevent and treat AF, and which patient groups should receive these interventions. The evidence for these available strategies and their place in contemporary guidelines are summarized.

Magnesium sulphate replacement therapy in cardiac surgery patients: A systematic review

OBJECTIVE

The objective of this review was to identify evidence to inform clinical practice guidelines for magnesium sulphate (MgSO₄) replacement therapy for postoperative cardiac surgery patients.

DATA SOURCES

Three databases were systematically searched: CINAHL Complete, MEDLINE Complete, and EmBase.

REVIEW METHOD USED

A systematic literature review method was used to locate, appraise, and synthesise available evidence for each step of the medication management cycle (indication, prescription, preparation, administration, and monitoring) for MgSO₄ replacement therapy. Database searches used combinations of synonyms for postoperation or surgery, cardiac, heart, arrhythmia, atrial fibrillation, and magnesium sulphate. Search results were independently screened for inclusion by two researchers at title, abstract, and full-text stages with good statistical agreement (kappa scores of 0.99, 0.87, and 1.00, respectively).

RESULTS

Twenty-four included studies reported varying methodologies, data collected, and medication management practices. Of these, 23 studies (95.8%) excluded patients with comorbidities commonly observed in clinical practice. This review identified low-level evidence for two practice recommendations: (i) concurrent administration of MgSO₄ with medications recommended as the best practice for prevention of postoperative atrial fibrillation and (ii) clinical and laboratory monitoring of magnesium blood serum levels, vital signs, and electrocardiography should be performed during MgSO₄ replacement therapy. Evidence to inform MgSO₄ replacement therapy for each medication management cycle step was limited; therefore, a guideline could not be developed.

CONCLUSIONS

Although MgSO₄ is routinely administered to prevent hypomagnesaemia in postoperative cardiac surgery patients, there was insufficient evidence to guide critical care nurses in each medication management cycle step for MgSO₄ replacement therapy. These findings precluded the development of comprehensive recommendations to standardise this practice. Poor standardisation can increase the risk for patient harm related to variation in clinical processes and procedural errors. In light of this evidence gap, consensus of expert opinion should be used as a strategy to guide MgSO₄ medication management.

The impact of maintaining serum potassium ≥3.6 mEq/L vs ≥4.5 mEq/L on the incidence of new-onset atrial fibrillation in the first 120 hours after isolated elective coronary artery bypass grafting - study protocol for a randomised feasibility trial for the proposed Tight K randomized non-inferiority trial

Background

Atrial fibrillation (AF) occurs in approximately one in three patients after cardiac surgery, and is associated with increased short-term and long-term mortality, intensive care unit (ICU) and hospital stay, and increased cost of care. In an attempt to reduce AF incidence in these patients, serum potassium (K+) levels are commonly maintained at the high end of normal (4.5–5.5 mEq/L). However, such potassium supplementation is without proven benefit, and is not without negative consequences. It carries clinical risk, negatively impacts patient experience and is both time-consuming and costly. This protocol describes a randomised controlled pilot trial to assess the feasibility of a proposed randomised non-inferiority trial to investigate the impact of maintaining serum potassium ≥ 3.6 mEq/L vs ≥ 4.5 mEq/L on the incidence of new-onset atrial fibrillation in the first 120 hours after isolated elective coronary artery bypass grafting.

Methods

Design: this is a randomized feasibility trial as a pilot for a randomized non-inferiority trial. Participants: are 160 patients undergoing isolated coronary artery bypass grafting at two centres. Allocation: patients will be randomized (1:1) to protocols aiming to maintain serum potassium at either ≥ 3.6 mEq/L (“relaxed control”) or ≥ 4.5 mEq/L (“tight control”). Primary analytic aim: was to assess the feasibility and acceptability of planning and delivering the intervention and trial methods to inform a full-scale non-inferiority trial. Outcome: the primary indicative efficacy outcome measures being field-tested are feasibility of participant recruitment and randomization, maintaining a protocol violation rate < 10%, and retaining 90% patient follow up 28 days after surgery. The primary clinical outcome measure of the future full “Tight K Study” will be incidence of AF after cardiac surgery.

Discussion

The Tight K Pilot will assess the feasibility of conducting the full trial, which is intended to confirm or refute the efficacy of current potassium management in preventing AF after cardiac surgery.

Trial registration

ClinicalTrials.gov, NCT03195647. Registered on 23 May 2017. Last updated 19June 2017.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2349-x) contains supplementary material, which is available to authorized users.

Potassium and Magnesium Supplementation Do Not Protect Against Atrial Fibrillation After Cardiac Operation: A Time-Matched Analysis

BACKGROUND

Despite a lack of demonstrated efficacy, potassium and magnesium supplementation are commonly thought to prevent postoperative atrial fibrillation (POAF) after cardiac operation. Our aim was to evaluate the natural time course of electrolyte level changes after cardiac operation and their relation to POAF occurrence.

METHODS

Data were reviewed from 2,041 adult patients without preoperative AF who underwent coronary artery bypass grafting, valve operation, or both between 2009 and 2013. In patients with POAF, the plasma potassium and magnesium levels nearest to the first AF onset time were compared with time-matched electrolyte levels in patients without AF.

RESULTS

POAF occurred in 752 patients (36.8%). At the time of AF onset or the matched time point, patients with POAF had higher potassium (4.30 versus 4.21 mmol/L, p < 0.001) and magnesium (2.33 versus 2.16 mg/dL, p < 0.001) levels than controls. A stepwise increase in AF risk occurred with increasing potassium or magnesium quintile (p < 0.001). On multivariate logistic regression analysis, magnesium level was an independent predictor of POAF (odds ratio 4.26, p < 0.001), in addition to age, Caucasian race, preoperative β-blocker use, valve operation, and postoperative pneumonia. Prophylactic potassium supplementation did not reduce the POAF rate (37% versus 37%, p = 0.813), whereas magnesium supplementation was associated with increased POAF (47% versus 36%, p = 0.005).

CONCLUSIONS

Higher serum potassium and magnesium levels were associated with increased risk of POAF after cardiac operation. Potassium supplementation was not protective against POAF, and magnesium supplementation was even associated with increased POAF risk. These findings help explain the poor efficacy of electrolyte supplementation in POAF prophylaxis.

Assessment of Blood Glucose and Electrolytes during Cardiopulmonary Bypass in Diabetic and Non-Diabetic Patients of Pakistan

Introduction:

Perioperative hyperglycemia has been shown to be related to higher levels of morbidity and mortality in patients on cardiopulmonary bypass (CPB) undergoing coronary artery bypass grafting (CABG), both diabetic and non-diabetic. Blood electrolytes, like sodium, potassium, calcium, and chloride play a very important role in the normal functioning of the body and can lead to a variety of clinical disorders if they become deficient. A minimal number of studies have been conducted on the simultaneous perioperative changes in both blood glucose and electrolyte levels during CPB in Pakistan. Therefore, our aim is to record and compare the changes in blood glucose and electrolyte levels during CPB in diabetic and non-diabetic patients.

Materials and Methods:

This was a prospective, observational study conducted on 200 patients who underwent CABG with CPB, from October 2014 to March 2015. The patients were recruited from the Cardiac Surgery Ward, Civil Hospital Karachi after they complied with the inclusion criteria. Repeated-measures analysis of variance (ANOVA) was used to compare the trend of the changes perioperatively for the two groups.

Results:

There was no significant difference in changes in blood glucose between the two groups (P = 0.62). The only significant difference detected between the two groups was for PaCO₂ (P = 0.001). Besides, further analysis revealed insignificant group differences for the trend changes in other blood electrolytes (P > 0.05).

Conclusion:

Our findings highlighted that there is no significant difference in blood electrolytes changes and the increase in blood glucose levels between diabetic and non-diabetic patients.

Decreasing IV Potassium in Pediatric Cardiac Intensive Care: Quality Improvement Project

OBJECTIVES

IV potassium supplementation is commonly used in the pediatric cardiovascular ICU. However, concentrated IV potassium chloride doses can lead to life-threatening complications. We report results of a quality improvement project aimed at decreasing concentrated IV potassium chloride exposure.

DESIGN

Retrospective evaluation of a quality improvement project aimed at reducing IV potassium chloride exposure.

SETTING

Pediatric cardiac ICU.

PATIENTS

All patients admitted to pediatric cardiac ICUs in April 2013 to September 2013 (preprotocol) and October 2013 to April 2014 (postprotocol).

INTERVENTIONS

A quality improvement team developed a potassium protocol aimed at maintaining serum potassium levels 3.0-5.5 mEq/L, via algorithm focused on early enteral supplementation. All patients receiving IV diuretics who had a serum potassium level less than 4.5 mEq/L and urine output more than 0.5 mL/kg/hr had protocol initiated with potassium chloride-containing IV fluids or enteral potassium chloride. Concentrated IV potassium chloride infusions were limited to asymptomatic patients with serum potassium less than 2.0 mEq/L and high-risk patients at less than 3.0 mEq/L. Serum potassium levels were measured once daily, and protocolized adjustments were made based on this level and concurrent diuretic therapy.

MEASUREMENTS AND MAIN RESULTS

Serum potassium, potassium chloride supplementation, patient cost, fluid administration, and arrhythmia incidence were compared pre and post protocol. Four hundred forty-three admissions were included (234 pre protocol and 209 post protocol). No significant differences were found in demographics. There was no difference in mean morning serum potassium after protocol implementation (3.85 [0.77] mEq/L before protocol and 3.89 [0.75] mEq/L after protocol; p = 0.90). Concentrated IV potassium chloride administration was decreased by 86% (331 vs 47 doses). With protocol, there was decreased incidence in days with one measured episode of hyperkalemia (11 vs 4/1,000 patient-days; p = 0.02) and a trend toward decreased hypokalemia (433 vs 400/1,000 patient-days; p = 0.05). Arrhythmia incidence was similar (p = 0.59).

CONCLUSIONS

Protocolized potassium management in pediatric cardiac intensive care patients decreased concentrated IV potassium chloride exposure and incidence of hyperkalemia. Lower potassium treatment threshold for IV potassium chloride was not associated with increased arrhythmias.

Management of postoperative atrial fibrillation in cardiac surgery patients

Postoperative atrial fibrillation (AF) is a common arrhythmia following cardiac surgery and contributes to patient morbidity, prolonged hospital stay, and increased financial costs. The risk of postoperative AF may increase based on patient characteristics or events that occur intraoperatively or postoperatively. An understanding of these risks may be helpful in identifying which patients would benefit from prevention strategies. Acute AF presentation may range from completely indolent to rapidly progressing hemodynamic instability. Patients without hemodynamic compromise can be managed conservatively with rate control or initiation of antiarrhythmic medications. Patients with significant hemodynamic instability should undergo direct current cardioversion. In the postoperative period, it is reasonable to initiate anticoagulation after 48 hours of sustained AF or frequent episodes of postoperative AF.

Features of an alternative hemodialysis method using a hemoconcentrator during cardiopulmonary bypass surgeries

Purpose:

This study clarified the features of a hemoconcentrator-based, alternative hemodialysis (ALTHD) method that improves the speed of serum potassium (K+) concentration adjustments, compared with dilutional ultrafiltration (DUF), during cardiopulmonary bypasses.

Methods:

Standardized bovine blood was recirculated (300 ml/min) through an in vitro hemoconcentrator circuit; hematocrit, K+ and glucose levels were measured at 5–20 min after DUF or ALTHD. We evaluated DUF at dialysis speeds of 50–250 ml/min and ALTHD at speeds of 50–1000 ml/min.

Results:

ALTHD rapidly corrected K+ and glucose concentrations at speeds up to 800 ml/min. ALTHD took 8.9 min to reach a K+ level of 4.5 mmol/L, faster than DUF (12.8 min). The ALTHD efficiency curves plateaued at 600 ml/min.

Conclusion:

ALTHD allowed faster adjustment of electrolyte levels, with peak efficiency at 600 ml/min. ALTHD has possible clinical application if available for potential use during all cardiopulmonary bypass surgeries involving extracorporeal circulation.

Development of an open-heart intraoperative risk scoring model for predicting a prolonged intensive care unit stay

BACKGROUND

Based on a pilot study with 34 patients, applying the modified sequential organ failure assessment (SOFA) score intraoperatively could predict a prolonged ICU stay, albeit with only 4 risk factors. Our objective was to develop a practicable intraoperative model for predicting prolonged ICU stay which included more relevant risk factors.

METHODS

An extensive literature review identified 6 other intraoperative risk factors affecting prolonged ICU stay. Another 168 patients were then recruited for whom all 10 risk factors were extracted and analyzed by logistic regression to form the new prognostic model.

RESULTS

The multivariate logistic regression analysis retained only 6 significant risk factors in the model: age ≥ 60 years, PaO2/FiO2 ratio ≤ 200 mmHg, platelet count ≤ 120,000/mm(3), requirement for inotrope/vasopressor ≥ 2 drugs, serum potassium ≤ 3.2 mEq/L, and atrial fibrillation grading ≥ 2. This model was then simplified into the Open-Heart Intraoperative Risk (OHIR) score, comprising the same 6 risk factors for a total score of 7-a score of ≥ 3 indicating a likely prolonged ICU stay (AUC for ROC of 0.746).

CONCLUSIONS

We developed a new, easy to calculate OHIR scoring system for predicting prolonged ICU stay as early as 3 hours after CPB. It comprises 6 risk factors, 5 of which can be manipulated intraoperatively.

Dose and type of crystalloid fluid therapy in adult hospitalized patients

OBJECTIVE

In this narrative review, an overview is given of the pros and cons of various crystalloid fluids used for infusion during initial resuscitation or maintenance phases in adult hospitalized patients. Special emphasis is given on dose, composition of fluids, presence of buffers (in balanced solutions) and electrolytes, according to recent literature. We also review the use of hypertonic solutions.

METHODS

We extracted relevant clinical literature in English specifically examining patient-oriented outcomes related to fluid volume and type.

RESULTS

A restrictive fluid therapy prevents complications seen with liberal, large-volume therapy, even though restrictive fluid loading with crystalloids may not demonstrate large hemodynamic effects in surgical or septic patients. Hypertonic solutions may serve the purpose of small volume resuscitation but carry the disadvantage of hypernatremia. Hypotonic solutions are contraindicated in (impending) cerebral edema, whereas hypertonic solutions are probably more helpful in ameliorating than in preventing this condition and improving outcome. Balanced solutions offer a better approach for plasma composition than unbalanced ones, and the evidence for benefits in patient morbidity and mortality is increasing, particularly by helping to prevent acute kidney injury.

CONCLUSIONS

Isotonic and hypertonic crystalloid fluids are the fluids of choice for resuscitation from hypovolemia and shock. The evidence that balanced solutions are superior to unbalanced ones is increasing. Hypertonic saline is effective in mannitol-refractory intracranial hypertension, whereas hypotonic solutions are contraindicated in this condition.

Evaluation of an electrolyte repletion protocol for cardiac surgery intensive care patients

BACKGROUND

Implementation of electrolyte repletion protocols to facilitate and ensure the safety of electrolyte control is common practice in intensive care units (ICUs). However, few protocols have been evaluated and validated.

OBJECTIVE

To evaluate the effectiveness and safety of an electrolyte repletion protocol in a large, homogeneous group of postoperative patients.

METHODS

A retrospective study of patients admitted to the surgical ICU following coronary artery bypass grafting or heart valve replacement was undertaken at the Centre hospitalier universitaire de Sherbrooke, a 682-bed tertiary care hospital in Sherbrooke, Quebec. The proportion of measured values for serum potassium concentration that were within the desired range was compared between patients treated according to the electrolyte repletion protocol and those treated with the traditional approach to electrolyte repletion. Management of magnesium, phosphorus, and ionized calcium balance was also compared. The incidence of cardiac arrhythmias was documented, and the safety of the electrolyte repletion protocol was evaluated by determining and comparing proportions of values for serum electrolyte concentration that were above the desired range.

RESULTS

In total, 627 patients were included in the study: 312 in the control group and 315 in the protocol group. The proportion of patients with 100% of morning values for serum potassium concentration within the normal range was significantly higher in the protocol group than in the control group (66.1% versus 56.8%; p = 0.018). In the protocol group, significantly more patients received one or more replacement doses of magnesium and phosphorus (p < 0.001). The proportions of serum electrolyte values above the normal range were similar between the 2 groups, and there was no difference in the incidence of cardiac arrhythmias.

CONCLUSIONS

The electrolyte repletion protocol was more efficacious than traditional electrolyte repletion in maintaining normal serum potassium concentration and was safe.

Response to intravenous potassium chloride supplementation in pediatric cardiac intensive care patients

Potassium chloride (KCl) supplementation is common among critically ill children. Intravenous (IV) KCl supplementation for pediatric patients is poorly characterized. This study aimed to examine the efficacy and safety of IV KCL and to determine factors affecting patient responses to IV KCL in the pediatric cardiac intensive care unit (CICU). A retrospective review of 211 children (794 KCl doses) undergoing cardiac surgery or a hospital stay for heart failure in the CICU of a tertiary care teaching and referral children's hospital in 2011 was performed. Demographic data, weight, height, creatinine, and concomitant medications during each KCl dose were recorded and analyzed. Body surface area (BSA), creatinine clearance, and change in [K(+)] were calculated. The median age of the children was 4 months (range, 10 days-18 years). In this study, 151 KCl doses were administered to neonates (19 %), 307 doses (39 %) to females, and 510 doses (64 %) to patients with a BSA smaller than 0.33 m(2) (a group with relative renal insufficiency). The mean KCl dose was 0.97 ± 0.006 mEq/kg. No adverse events were associated with IV KCl administration. Blood/plasma [K(+)] increased 0.8 ± 0.02 mEq/L. The responses to KCl did not differ significantly between males and females, between neonates and children, or between patients with a BSA smaller than 0.33 m(2) and those with a BSA of 0.33 m(2) or larger. The responses to IV KCl were attenuated by concomitant furosemide (p = 0.01), amphotericin B (p < 0.01), and KCl in parenteral nutrition (p < 0.01). The responses were augmented by concomitant enalapril (p = 0.03), ethacrynic acid (p < 0.001), and hemodialysis (p < 0.01). Intravenous KCl can be administered safely for CICU patients. Responses to KCl are altered when it is given with certain medications. Intravenous KCl should be used cautiously in children receiving angiotensin-converting enzyme inhibitors. Future studies are needed for further characterization of factors affecting responses to IV KCl in children.