Weiling Liu

Incidence of and risk factors for difficult ventilation via a supraglottic airway device in a population of 14 480 patients from South-East Asia

Difficult airway practice guidelines include the use of a supraglottic airway device as part of the armamentarium to provide and maintain ventilation and oxygenation. We retrospectively reviewed 14 480 patients aged ≥ 18 years who underwent general anaesthesia. We identified 74 (0.5%) patients whose lungs were identified as having been difficult to ventilate via a supraglottic airway device, and 29 (0.2%) patients in whom device placement failed. Multivariate analysis identified four risk factors for difficult ventilation via a supraglottic airway device: male sex (OR 1.75, 95% CI 1.07–2.86, p = 0.02); age > 45 years (OR 1.70, 95% CI 1.01–2.86, p = 0.04); short thyromental distance (OR 4.35, 95% CI 2.31–8.17, p < 0.001); and limited neck movement (OR 2.75, 95% CI 1.02–7.44, p = 0.04). Adverse respiratory events including oxygen desaturation, hypercapnoea, laryngospasm, and bronchospasm occurred in 17 patients (22%). The incidence of difficult ventilation via a supraglottic airway device was 0.5% in a large cohort of South‐East Asian patients.

A proposal for a new scoring system to predict difficult ventilation through a supraglottic airway

BACKGROUND The aim of this study was to propose and validate a new clinical score to predict difficult ventilation through a supraglottic airway device. METHODS The score was proposed from our previously reported derivation data, and we prospectively validated the score in 5532 patients from November 2013 to April 2014. Predictive accuracy of the score was compared by the area under the receiver operating characteristic (ROC) curve (AUC). We assigned point values to each of the identified four risk factors: male, age >45 yr, short thyromental distance, and limited neck movement, their sum composing the score. The score ranged between 0 and 7 points. The optimal predictive level of the score was determined using ROC curve analysis. RESULTS The AUC of the score was 0.75 (95% CI 0.66 to 0.84) in the validation data set, and was similar to that in the derivation data set (0.80; 95% CI 0.75 to 0.86). In derivation and validation data sets, the incidence of low risk categories (scores 0-3) was 0.42% vs 0.32% and of high risk categories (scores 4-7) was 3% vs 1.7% respectively. A score 4 or greater is associated with a six to seven fold increased risk of difficult ventilation through a supraglottic airway device. CONCLUSIONS The new score for prediction of difficult ventilation through a supraglottic airway device is easy to perform and reliable, and could help anaesthetists plan for difficult airway management.

The Association of Acute Kidney Injury and Atrial Fibrillation after Cardiac Surgery in an Asian Prospective Cohort Study

AbstractAcute kidney injury (AKI) and atrial fibrillation (AF) after cardiac surgery are common occurrences and increase patient morbidity and mortality. Inflammation plays a role in increased incidence of AF in patients with chronic kidney disease (CKD); reactive oxygen species and inflammatory markers which are increased in patients with CKD were found to affect the proper functioning of the intracellular ion channels, connexions (transmembrane proteins found in intercellular gap junctions), and electrical homogeneity of the extracellular matrix which are essential for electrical stability and proper conduction of electrical impulses in the atrium. However, it is not known if similar mechanisms are also involved in AKI. We tested the hypothesis that patients with AKI after cardiac surgery have a higher incidence of postoperative AF.Data from 2885 patients, who had undergone cardiac surgery between August 2008 and July 2012 from the Singapores 2 major heart centers, were obtained prospectively. Postoperative AKI was defined using the Acute Kidney Injury Network criteria. The primary outcome was postoperative AF, and subjects were considered to have postoperative AF if the AF lasted more than an hour, affected hemodynamics, or required medical treatment.The incidence of AKI was 29.7% and the incidence of postoperative AF was 16.8%. A total of 27.7% of AKI patients developed AF. Patients with AKI had a 2-fold increased risk of developing AF (relative risk [RR], 1.716; 95% confidence interval [CI], 1.433–2.055; P < 0.001). The following factors were found to independently increase the risk of AF in patients with AKI: age (RR, 1.011; 95% CI, 1.000–1.022; P = 0.04), low preoperative hemoglobin (RR, 0.942; 95% CI, 0.888–1.000; P = 0.05), low preoperative estimated glomerular filtration rate (eGFR) (RR, 0.987; 95% CI, 0.980–0.994; P < 0.001), and lowest hematocrit during bypass (RR, 0.943; 95% CI, 0.910–0.978; P < 0.001).Patients with AKI are more likely to develop postoperative AF. These patients were older and had lower preoperative hemoglobin, eGFR, and lower nadir hematocrit during bypass. Identification of high-risk AKI patients with early prevention and treatment of AF should reduce the long-term morbidity and mortality among Asian patients undergoing cardiac surgery.

Wider Perioperative Glycemic Fluctuations Increase Risk of Postoperative Acute Kidney Injury: A Prospective Cohort Study.

AbstractAcute kidney injury (AKI) is a common complication after cardiac surgery. Recent studies have revealed emerging associations between the magnitude of acute glycemic fluctuations and intensive care unit (ICU) mortality rates. However, the effect of acute glycemic fluctuations on the development of postoperative AKI remains unclear. Thus, we aim to investigate the effect of the magnitude of acute perioperative glycemic fluctuations on the incidence of postoperative AKI.We conducted a prospective cohort study by prospectively obtaining data from all patients who underwent elective coronary artery bypass grafting in a tertiary heart institution from 2009 to 2011. The magnitude of the difference between the highest and lowest perioperative glucose levels within 48 hr was calculated as a measure of perioperative glycemic fluctuation. Patients were divided into 4 groups for analysis based on the magnitude of perioperative glycemic fluctuation-A: 0 to 2 mmol/L; B: >2 to 4 mmol/L; C: >4 to 6 mmol/L; and D: >6 mmol/L. We analyzed the incidence of postoperative AKI, ICU mortality and ICU length of stay as primary and secondary outcomes, respectively. Both univariate and multivariate analyses were used.We analyzed data from 1386 patients. The overall incidence of AKI was 29.9% and increased with wider glycemic fluctuation. The incidence of AKI was statistically highest in Group D (38.3%), followed by Groups C (28.6%), B (21.7%), and A (17.4%), respectively (P[REPLACEMENT CHARACTER]=[REPLACEMENT CHARACTER]0.001). A similar trend was observed among both diabetics and nondiabetics (P[REPLACEMENT CHARACTER]=[REPLACEMENT CHARACTER]0.001 and P[REPLACEMENT CHARACTER]=[REPLACEMENT CHARACTER]0.002, respectively). Multivariate logistic regression showed the magnitude of perioperative glycemic fluctuations to be an independent risk factor in the development of AKI (P < 0.001, odds ratio 1.180, 95% confidence interval 1.116-1.247). ICU length of stay was statistically highest in Group D (58.3[REPLACEMENT CHARACTER]hr) compared with Groups C (44.5[REPLACEMENT CHARACTER]hr), B (37.3[REPLACEMENT CHARACTER]hr), and A (32.8[REPLACEMENT CHARACTER]hr, P[REPLACEMENT CHARACTER]=[REPLACEMENT CHARACTER]0.003). ICU mortality rate was comparable among all 4 groups (P[REPLACEMENT CHARACTER]=[REPLACEMENT CHARACTER]0.172).Wide acute perioperative glycemic fluctuations should be avoided as they are associated with a significantly increased risk of AKI and ICU length of stay in both the diabetics and the nondiabetics.

Persistent Kidney Injury at Hospital Discharge After Cardiac Surgery With Cardiopulmonary Bypass in Patients With Normal Preoperative Serum Creatinine and Normal Estimated Glomerular Filtration Rate

OBJECTIVE Acute kidney injury is a serious complication after cardiac surgery. Although it resolves in most cases, a significant portion of patients persistently have raised creatinine values at hospital discharge. These patients are at greater risk for developing chronic kidney disease and mortality. Therefore, the present study aimed to ascertain risk factors of persistent acute kidney injury after cardiac surgery in patients with normal preoperative renal function. DESIGN Prospective cohort study. SETTING Tertiary heart centers. PARTICIPANTS 2,181 adult cardiac surgical patients, predominantly Asian. INTERVENTIONS Cardiac surgery between August 2008 and July 2012. MEASUREMENTS AND MAIN RESULTS The incidence of acute kidney injury, as defined by the Acute Kidney Injury Network stage 1 criteria, was 21.7%. At discharge, 10.5% of these patients had persistent kidney injury, which was defined as a ≥ 26.4 μmol/L (≥ 0.3 mg/dL) difference between preoperative and discharge creatinine levels and/or a 50% rise in serum creatinine. These patients were more likely to be aged ≥ 70 years (relative risk = 2.232, 95% confidence interval = 1.326-3.757, p = 0.003), have a higher peak postoperative creatinine value within 48 hours (relative risk = 1.007, 95% confidence interval = 1.004-1.010, p<0.001), and have lower hemoglobin on intensive care unit arrival (relative risk = 0.759, 95% confidence interval = 0.577-0.998, p = 0.048). CONCLUSIONS Age ≥ 70 years, higher peak postoperative creatinine within 48 hours, and lower hemoglobin on intensive care unit arrival are associated with persistent acute kidney injury. Strategies to improve hemoglobin on intensive care unit arrival potentially can reduce persistent acute kidney injury. The authors recommend that patients aged ≥ 70 years undergo further renal evaluation for better risk stratification.

A Clinical Prediction Model for Postcardiac Surgery Atrial Fibrillation in an Asian Population.

BACKGROUND:Postoperative atrial fibrillation (AF) is associated with increased morbidity, mortality, and resource utilization. Current prediction models for postoperative AF are based primarily on Western populations. In this study, we sought to develop a clinical prediction rule for postcardiac surgery AF for a multiethnic Asian population. METHODS:Two thousand one hundred sixty-eight patients undergoing coronary artery bypass graft or valve surgery with cardiopulmonary bypass were prospectively enrolled in this observational study between August 2008 and July 2012 at Singapore’s 2 national heart centers. Postoperative AF was defined as an irregularly irregular electrocardiogram rhythm without identifiable P wave after surgery and before hospital discharge that lasted more than an hour, or affected hemodynamics (ie, systolic blood pressure <90 mm Hg or mean arterial blood pressure <60 mm Hg), or required medical treatment. Patients had continuous telemetry monitoring for at least 72 hours while in the intensive care or high-dependency units postoperatively. Subsequently, patients had a 12-lead electrocardiogram daily and when symptomatic. Multivariable logistic regression was used to determine significant predictors of postcardiac surgery AF, and a scoring system was developed. The model was internally validated in an additional 500 patients. RESULTS:Postoperative AF occurred in 17.3% of patients, with a peak occurrence in the first 72 hours after surgery. Multivariate logistic regression analysis identified age ≥65 years (odds ratio [OR], 1.44; 95% confidence interval [CI], 1.11–1.85, P = 0.005), history of AF (OR, 3.65; 95% CI, 2.52–5.30, P < 0.001), inotrope use (OR, 1.74; 95% CI, 1.31–2.32, P < 0.001), cardiopulmonary bypass duration >120 minutes (OR, 1.92; 95% CI, 1.47–2.52, P < 0.001), and Chinese ethnicity (Chinese versus Indian OR, 2.09; 95% CI, 1.28–3.41, P = 0.003) or Malay (Malay versus Indian OR, 2.43; 95% CI, 1.36–4.05, P = 0.002) to be independently associated with postoperative AF. The area under the receiver-operator characteristic curve of the model was 0.704 (95% CI, 0.674–0.734). Internal validation produced an area under the receiver-operator characteristic curve of 0.756 (95% CI, 0.690–0.821). CONCLUSIONS:Clinical risk factors for AF after cardiac surgery in an Asian population are similar to that reported from primarily Western populations, but specific ethnicity influences susceptibility.

Wider perioperative glycemic fluctuations increase risk of postoperative atrial fibrillation and ICU length of stay

Introduction Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery associated with increased morbidity and mortality. Although sustained hyperglycemia is a known risk factor of AF and poor ICU outcomes, emerging in-vitro studies reveal acute glycemic fluctuations to be an additional independent predictor of AF. The effect of acute glycemic fluctuations on the incidence of POAF in the clinical setting remains unclear. We aim to investigate the effect of the magnitude of acute perioperative glycemic fluctuations on the incidence of POAF in a multi-ethnic Southeast-Asian population. Methods We obtained data from1743 patients who underwent elective CABG in a tertiary heart centre from 2009–2011. Patients were kept to a tight baseline glycemic control in accordance with hospital protocol. The magnitude of the difference between the highest and lowest perioperative glucose levels up till the first 48 postoperative hours was employed as a measure of glycemic fluctuation. Patients were divided into 4 groups for analysis based on the magnitude of glycemic fluctuation:A)0-2mmol/L(N = 147); B)>2-4mmol/L(N = 426); C)>4-6mmol/L(N = 513); D)>6mmol/L(N = 657).Our primary outcome was the incidence of POAF. Secondary outcomes included ICU and 30-day mortality and length of stay. Results The overall incidence of POAF was 14.7%. This increased as the magnitude of glycemic fluctuation increased, and was statistically highest in Group D(16.4%) as compared with the other 3 sub-groups. Multivariate logistic regression revealed the magnitude of perioperative glycemic fluctuation to be an independent risk factor of POAF(O.R.1.06, 95% C.I.1.01–1.11, p = 0.014).ICU length of stay was statistically highest in Group D(63.1 hours, p = < .001). However, ICU and 30 day mortality rates were similar among the 4 groups. Conclusion Increased magnitudes of acute perioperative glycemic fluctuations are associated with a significantly increased risk of POAF and length of ICU stay; and should therefore be minimised but balanced against the risks of hypoglycemia so as to avoid POAF and optimise patient outcomes.