Postoperative Variability Research Articles

Perioperative Glycemic Variability Influences Infection Rates Differently Following Revision Hip and Knee Arthroplasty

IntroductionRecent investigations have determined that abnormal postoperative glycemia following primary total joint arthroplasty is associated with adverse events. Our study aimed to determine if hyperglycemia and glycemic variability following aseptic revision total joint arthroplasty (rTJA) were associated with periprosthetic joint infection (PJI) within two years postoperatively. MethodsA retrospective review was performed of 2,208 patients within a single institution undergoing aseptic rTJA from 2012 to 2019. Postoperative glucose values were recorded. Glycemic variability was measured via three parameters: coefficient of variation (%CV), mean amplitude of glycemic excursions (MAGE), and J-index. Logistic regression analyses were performed to examine associations with PJI at 90-day, 1-, and 2-year follow-up. ResultsIn revision hips, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses, except for MAGE, which predicted PJI at one year (P = 0.045); body mass index (BMI) was the only factor associated with PJI at all timepoints in all models. In revision knees, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses; however, PJI rates differed between diabetics and non-diabetics at all time-points (P < 0.05). ConclusionsOur findings illustrate that decreasing preoperative BMI and postoperative glycemic variability may be critical in reducing PJI rates in revision hips. Furthermore, patients who have diabetes should be counseled that they remain at higher risk of PJI regardless of perioperative glucose control after revision knee surgery.

P18. Evaluating the impact of NPO duration on postoperative glucose variability and outcomes following lumbar fusion in diabetic patients

P18. Evaluating the impact of NPO duration on postoperative glucose variability and outcomes following lumbar fusion in diabetic patients

Increased Postoperative Glycemic Variability Is Associated with Increased Revision Surgery Rates in Diabetic Patients Undergoing Hip Fracture Fixation

Increased Postoperative Glycemic Variability Is Associated with Increased Revision Surgery Rates in Diabetic Patients Undergoing Hip Fracture Fixation

Understanding Hematoma Risk: Study of Patient and Perioperative Factors in a Large Cohort of Young Women Undergoing Reduction Mammaplasty.

Despite high satisfaction rates, reduction mammaplasty can have complications such as hematoma. Factors such as age, tobacco use, and comorbidities are known contributors, whereas the influence of race, BMI, certain medications, and blood pressure (BP) remain contentious. This study investigates hematoma risk factors in young women undergoing reduction mammaplasty. A retrospective review was conducted including all female patients who underwent bilateral reduction mammaplasty at a single institution between 2012 and 2022. Data on demographics, BMI, medical comorbidities, surgical techniques, medications, and perioperative BP were collected. Differences between patients who developed a hematoma and those who did not were assessed using chi-square, Fisher's exact, and t -tests. The relationship between perioperative BP and hematoma formation was assessed using logistic regression. Of 1,754 consecutive patients, 3% developed postoperative hematoma of any kind, with 1.8% returning to the operating room. Age (odds ratio [OR] 1.14, p = 0.01) and ketorolac use (OR 3.93, p = 0.01) were associated with hematoma development. Controlling for baseline BP, each 10 mmHg incremental increase in peak intraoperative BP (systolic BP [SBP]: OR 1.24, p = 0.03; mean arterial pressure: OR 1.24, p = 0.01) and postoperative BP (SBP: OR 1.41, p = 0.01; mean arterial pressure: OR 1.49, p = 0.01) escalated the odds of hematoma. Postoperative SBP variability also incrementally increased hematoma odds (OR 1.48, p < 0.01). Other factors, including race and surgical technique, were not significantly influential. Age, ketorolac use, and intra- and postoperative BP peaks and variability are risk factors for hematoma in reduction mammaplasty. This emphasizes the importance of perioperative BP management and optimizing pain management protocols.

Effect of Preoperative Corticosteroids on Postoperative Glucose Control in Total Joint Arthroplasty

BackgroundDexamethasone is a commonly used perioperative medication for the management of postoperative nausea and vomiting following total joint arthroplasty (TJA). However, concerns have been raised about its potential to cause hyperglycemia. This study aimed to investigate the impact of dexamethasone administration on glucose levels and complications in both diabetic and nondiabetic patients undergoing TJA. MethodsWe performed a retrospective review of 1928 patients who underwent primary total knee and hip arthroplasty procedures at a large tertiary medical institution. Patients were divided into 2 groups based on whether they received preoperative dexamethasone. Postoperative blood glucose values and variability were measured, and data on complications were collected. We performed statistical analysis using descriptive analysis, multivariate logistic regression models, negative binomial regression, and a subset analysis to assess the impact of dexamethasone dose on postoperative glycemic control. ResultsPreoperative dexamethasone did not significantly increase the mean glucose, fasting glucose, glucose variability, or 90-day complications in both the diabetic and nondiabetic groups. Nondiabetic patients who received dexamethasone had a significantly lower rate of intensive care unit admission (P < .01). Additionally, patients who received dexamethasone had a significantly shorter length of hospital stay compared to those who did not (P < .001). ConclusionsPreoperative dexamethasone administration is a safe and effective method for preventing postoperative nausea and vomiting in patients undergoing TJA without significant adverse effects on glucose levels, glucose variability, or infection rates in both diabetics and nondiabetics. Preoperative dexamethasone decreases postoperative length of stay.

Impact of early postoperative blood glucose variability on serum endocan level in cardiac surgery patients: a sub study of the ENDOLUNG observational study

BackgroundEarly postoperative glycemic variability is associated with worse outcome after cardiac surgery, but the underlying mechanisms remain unknown. This study aimed to describe the relationship between postoperative glycemic variability and endothelial function, as assessed by serum endocan level in cardiac surgery patients.MethodsWe performed a post hoc analysis of patients included in the single-center observational ENDOLUNG study. Adult patients who underwent planned isolated coronary artery bypass graft surgery were eligible. Postoperative glycemic variability was assessed by calculating the coefficient of variability (CV) of blood glucose measured within 24 (CV24) and 48 (CV48) hours after surgery. Serum endocan level was measured at 24 (Endocan24) and 48 (Endocan48) hours after surgery. Pearson’s correlation coefficient with 95% confidence interval (95% CI) was calculated between CV24 and Endocan24, and between CV48 and Endocan48.ResultsData from 177 patients were analyzed. Median CV24 and CV48 were 18% (range 7 to 39%) and 20% (range 7 to 35%) respectively. Neither CV48 nor CV24 were significantly correlated to Endocan48 and Endocan24 respectively (r (95% CI) = 0.150 (0.001 to 0.290; and r (95% CI) = 0.080 (-0.070 to 0.220), respectively).ConclusionsEarly postoperative glycemic variability within 48 h after planned cardiac surgery does not appear to be correlated with postoperative serum endocan level.Clinical trial registration numberNCT02542423.

Changes in Cerebral Regional Oxygen Saturation Variability in Neonates Undergoing Cardiac Surgery: A Prospective Cohort Study.

Near-infrared spectroscopy is routinely used in the monitoring of cerebral regional oxygen saturation (crSO2) in neonates following congenital heart surgery. Decreased postoperative crSO2 variability in these patients is associated with worse clinical outcomes, including neurodevelopmental outcomes. We sought to explore changes in crSO2 variability between the preoperative and postoperative periods and associations with short-term clinical outcomes in neonates undergoing cardiac surgery. We performed a prospective cohort study of neonates undergoing cardiac surgery with cardiopulmonary bypass between November 2019 and May 2021. We calculated crSO2 variability using averaged 1min of crSO2 values for a minimum of 12h before, and the first 48h following surgery. 37 neonates (median age at start of monitoring 4days (interquartile range 2-5days)) were included in our study. We observed a 30% decrease in crSO2 variability between the preoperative and postoperative monitoring periods (p < 0.001). Preoperative crSO2 variability increased by 9% (p = 0.009) for each additional postnatal day. There were no associations between the degree of decrease in crSO2 variability postoperatively and class of cardiac lesion (e.g., aortic arch obstruction, single ventricle physiology) or short-term postoperative clinical outcomes. There was a significant decrease in postoperative crSO2 variability following neonatal cardiac surgery as compared to the preoperative period, likely influenced by several factors. The impact of interventions on crSO2 variability and resultant influence on long-term outcomes, such as neurodevelopmental outcomes, requires further exploration.

Determining the risk factors for hyperglycemia and glucose variability after total knee arthroplasty with continuous glucose monitoring: An observational cohort study

Introduction: Periprosthetic joint infection after total knee arthroplasty (TKA) is a devastating complication and different risk factors, including hyperglycemia and increased glucose variability, have been suggested for this condition in previous literature. Our study aims to investigate the risk factors for postoperative hyperglycemia and glucose variability in patients undergoing unilateral primary TKA with continuous glucose monitoring (CGM) technology. Methods: Demographic factors, diabetic statuses, hemoglobin A1c (HbA1c) levels, and fructosamine levels of patients undergoing unilateral primary TKA were recorded preoperatively. These patients would either received 16 mg intravenous dexamethasone or no dexamethasone before their surgery as part of perioperative management. From the day of admission to postoperative day 4, CGM device monitored these patients’ blood glucose level, time of hyperglycemia, and glucose variability. Correlation and multivariate regression analysis were performed between the risk factors and the outcome measures, with multicollinearity between the predictor variables checked, to find out the most potent risk factors for postoperative hyperglycemia. Results: Eighty-three patients with primary unilateral TKA were analyzed. Diabetic, prediabetic, and nondiabetic patients were composed of 26.5%, 47.0%, and 26.5%, respectively. The average of HbA1c and fructosamine level was 6.0% and 249.3 mmol/L, respectively; 65.1% of the patients received 16 mg dexamethasone perioperatively. Multivariate regression analysis found that HbA1c, fructosamine, and dexamethasone injections are the significant risk factors for the percentage of time in hyperglycemia ( R2 = 0.374, p &lt; 0.001) and average blood glucose level ( R2 = 0.493, p &lt; 0.001), with HbA1c having the highest standardized coefficient, followed by fructosamine and dexamethasone injections. Although dexamethasone usage was significant in multivariate regression analysis on predicting glucose variability, the effect size of the model is very weak ( R2 = 0.05, p &lt; 0.05). Conclusion: The most potent risk factor for hyperglycemic time and increased average blood glucose is HbA1c level, followed by fructosamine level and dexamethasone injections. No strong correlation was found between the factors in our study and patients’ glucose variability.

Extended Preoperative Audiometry for Outcome Prediction and Risk Analysis in Patients Receiving Cochlear Implants.

The outcome of cochlear implantation has improved over the last decades, but there are still patients with less benefit. Despite numerous studies examining the cochlear implant (CI) outcome, variations in speech comprehension with CI remains incompletely explained. The aim of this study was therefore to examine preoperative pure-tone audiogram and speech comprehension as well as aetiology, to investigate their relationship with postoperative speech comprehension in CI recipients. A retrospective study with 664 ears of 530 adult patients was conducted. Correlations between the target variable postoperative word comprehension with the preoperative speech and sound comprehension as well as aetiology were investigated. Significant correlations were inserted into multivariate models. Speech comprehension measured as word recognition score at 70 dB with CI was analyzed as (i) a continuous and (ii) a dichotomous variable. All variables that tested preoperative hearing were significantly correlated with the dichotomous target; with the continuous target, all except word comprehension at 65 dB with hearing aid. The strongest correlation with postoperative speech comprehension was seen for monosyllabic words with hearing aid at 80 dB. The preoperative maximum word comprehension was reached or surpassed by 97.3% of CI patients. Meningitis and congenital diseases were strongly negatively associated with postoperative word comprehension. The multivariate model was able to explain 40% of postoperative variability. Speech comprehension with hearing aid at 80 dB can be used as a supplementary preoperative indicator of CI-aided speech comprehension and should be measured regularly in the clinical routine. Combining audiological and aetiological variables provides more insights into the variability of the CI outcome, allowing for better patient counselling.

The impact of postoperative blood glucose levels on complications and prognosis after esophagectomy in patients with esophageal cancer.

This study aimed to characterize postoperative blood glucose fluctuation in patients who underwent esophagectomy for esophageal cancer, and to define its impact on complications and prognosis. The subjects of this retrospective study were 284 patients who underwent esophagectomy at Osaka University Hospital between 2015 and 2017. Data analyzed included clinicopathological background, the immediate postoperative blood glucose level (IPBG), postoperative blood glucose variability (PBGV), insulin dosage, postoperative complications, and prognosis. The median IPBG and PBGV were 170 (64-260) mg/dl and 64.5 (11-217) mg/dl, respectively. Postoperative pneumonia was more common in patients with PBGV > 100mg/dl (P = 0.015). Patients with IPBG < 170mg/dl had significantly worse 5-year overall survival (OS) and 5-year recurrence-free survival (RFS) than those with IPBG > 170mg/dl (54.5% vs. 80.4%, respectively, [P < 0.001] and 44.3% vs. 69.3%, respectively, [P = 0.001]). The 5-year OS rates were 43.5%, 68.3%, 80.6%, and 79.0% for patients with IPBG < 154, 154-170, 170-190, and ≥ 190mg/dl, respectively. The corresponding 5-year RFS rates were 38.1%, 52.4%, 77.0%, and 61.3%, respectively. Multivariate analysis revealed that IPBG < 154mg/dl and pathological stage were independent poor prognostic factors for OS. PBGV was associated with postoperative pneumonia, and low IPBG was an independent poor prognostic factor for patients with esophageal cancer.

Perioperative blood glucose variability and autonomic nervous system activity in on-pump cardiac surgery patients: Study protocol of a single-center observational study.

On-pump coronary artery bypass graft (CABG) and surgical valve replacement (SVR) are high-risk procedures. Several studies reported that perioperative blood glucose (BG) variability was independently associated with impaired postoperative outcome. However, the underlying mechanisms contributing to increased perioperative BG variability and to its deleterious impact remain unknown. The hypothesis of the study is that perioperative BG variability could be related to perioperative alteration of the autonomic nervous system (ANS) activity and to preoperative BG variability. We designed a prospective observational single-center study. Four groups of 30 patients will be studied: group 1, including insulin-requiring type 2 diabetic patients undergoing on-pump CABG; group 2, including non-insulin-requiring type 2 diabetic patients undergoing on-pump CABG; group 3, including non-diabetic patients undergoing aortic SVR; and group 4, including non-diabetic patient undergoing on-pump CABG. Preoperative (baseline) and postoperative BG variability will be quantified using the Abbott's Freestyle Libre Pro sensor allowing for continuous subcutaneous BG monitoring. Preoperative (baseline) and postoperative ANS activity will be measured using noninvasive continuous heart rate monitoring (Mooky HR memory®). Blood level and urinary concentration of inflammatory and endothelial dysfunction biomarkers will be measured from blood and urinary samples at the end of the surgery and on postoperative day 1 and 2. The primary objective is to describe the relationship between baseline BG variability and postoperative BG variability. The secondary objectives are to describe the relationship: between baseline and postoperative BG variability according to the diabetes phenotype and to the type of surgery; between the ANS activity and the BG variability; and between postoperative BG variability and, urinary and blood biomarkers.

Association between postoperative delirium and heart rate variability in the intensive care unit and readmissions and mortality in elderly patients with cardiovascular surgery.

This study aimed to investigate the relationship between heart rate variability (HRV), a parameter of the autonomic nervous system activity (ANSA), and postoperative delirium and postoperative events. This retrospective cohort study included elderly patients aged 65years or older who were admitted to the intensive care unit (ICU) after cardiovascular surgery. ANSA was measured using HRV parameters for 1h at daytime and 1h at night-time before ICU discharge. The primary endpoint was the effect of HRV parameters and delirium on mortality and readmission rates within 1year after discharge, and the secondary endpoint was the association between HRV parameters and delirium. Cox proportional hazards models were used to examine the association between HRV parameters and postoperative events by adjusting for delirium and pre and postoperative information. A total of 71 patients, 39 without delirium and 32 with delirium, met the inclusion criteria. The incidence of death and readmission within 1year was significantly higher in the delirium group and in the group with higher daytime HF (high frequency power) and r-MSSD (square root of the squared mean of the difference of successive NN intervals), parameters of the parasympathetic nervous system activity (PNSA), than that in other groups. Furthermore, the delirium group had significantly higher HF and r-MSSD than the nondelirium group. Even after adjusting for confounding factors in the multivariate analysis, a trend of higher daytime HF and r-MSSD was observed, indicating a significant effect on the occurrence of combined events within 1year of discharge. ICU delirium has been associated with higher daytime HF and r-MSSD, parameters of PNSA. ICU delirium was a prognostic factor, and increased daytime PNSA may worsen the prognosis of elderly patients after cardiovascular surgery.

A nomogram for accurately predicting the surgical site infection following transforaminal lumbar interbody fusion in type 2 diabetes patients, based on glycemic variability.

Surgical site infection (SSI) is a common and serious complication of transforaminal lumbar interbody fusion (TLIF), and the occurrence of SSI usually leads to prolonged hospitalisation, increased medical costs, poor prognosis, and even death. The objectives of this study were to compare the incidence of SSI in patients with type 2 diabetes, investigate the correlation between perioperative glycemic variability and postoperative SSI, and develop a nomogram model to predict the risk of SSI. This study retrospectively analysed 339 patients with type 2 diabetes who underwent TLIF in the spinal surgery department of the Affiliated Zhongda Hospital of Southeast University from January 2018 to September 2021. The medical records of all patients were collected, and postoperative infection cases were determined according to the diagnostic criteria of surgical site infection. The risk factors for postoperative SSI were analysed by univariate and multivariate logistic regression. And Nomogram prediction model was established and validated. The nomogram incorporated seven independent predictors. Preoperative FPG-CV was the most important independent risk predictor of SSI, followed by preoperative MFBG, duration of drain placement, postoperative FPG-CV, preoperative blood glucose control scheme, duration of diabetes >5 years, and the number of fused vertebrae ≥2. The nomogram showed good diagnostic accuracy for the SS of both the training cohort and the validation cohort (AUC=0.915 and AUC=0.890). The calibration curves for the two cohorts both showed optimal agreement between nomogram prediction and actual observation. In conclusion, preoperative and postoperative glycemic variability is closely related to the occurrence of SSI. We developed and validated a nomogram to accurately predict the risk of SSI after TLIF surgery. It's helpful for spinal surgeons to formulate reasonable treatment plans and prevention strategies for type 2 diabetes patients.

215.15: Perioperative Changes in Glycemic Indices Using Continuous Glucose Monitoring in Kidney Transplantation Recipients

Introduction: The plethora of data on glycemic excursions and additional indices, such as the glycemic variability (GV) and glucose management indicator (GMI), which is an estimated A1C derived from the glucose measures that the continuous glucose monitoring (CGM) system provides, has revolutionized the study of dysglycemia on various organs and stress induced situations. GV has been proposed to be a risk factor for complication of diabetes and increased mortality and predictive marker for hypoglycemia. The purpose of this study was to describe the changes in glycemic patterns of kidney transplant recipients during the perioperative period using CGM and attempt to define the clinical significance of the glycemic variability that occur. Method: A prospective observational study starting May 1st, 2021 was conducted for patients who underwent kidney transplantations at our center. Upon enrollment, a CGM system was applied and CGM was undertaken 2 weeks preoperatively and 2 weeks postoperatively. No additional interventions were undertaken. Clinical characteristics and transplant related outcomes were collected along with glucose profile using the CGM system. Results: By March 1, 2022, a total of 72 patients were enrolled in the study and completion of both preoperative and postoperative CGM was accomplished in 51 patients. A hyperglycemic tendency was seen postoperatively than preoperatively with higher mean glucose levels (110.49±38.65 mg/dL vs. 134.24±32.74 mg/dL; p=<0.001), longer time above glucose level of 250mg/dL (3.13±9.19% vs. 4.24±8.118%; p=0.001), higher daily peak glucose levels (129.52±52.32mg/dL vs. 160.58±42.47mg/dL; p=<0.001), higher daily nadir glucose levels (85.84±26.73mg/dL vs. 105.27±27.83mg/dL p=<0.001). The GV and GMI as measured by the CGM system were also significantly increased from preop to postop; 28.48±7.78% vs. 32.70±9.05%, p=0.004 and 5.91±0.92% vs 6.89±2.51%, p=<0.001, respectively. Linear correlations fitted for postoperative glucose variability showed a positive correlation with preoperative glucose variability (r=0.40; p=0.006) and postoperative one-month hbA1c (r=0.35; p=0.023). A negative correlation with postoperative glucose variability and postoperative one-month fasting insulin (r=0.40; p=0.009), HOMA-B (r=-0.34; p=0.0029) and c-peptide (r=-0.49; p=0.001) was seen. Conclusion: The continuous glucose monitoring of kidney transplantation recipients showed an overall hyperglycemic change in the post-transplant period with increased GV that was also reflected by an increase GMI and correlation with postoperative 1 month hbA1c. The negative correlations with postoperative GV and postoperative 1 month fasting insulin, c-peptide and HOMA-B values may relate to GV as a predictive marker of hypoglycemia, as reported in other studies. However, as an interim report of an ongoing prospective study, no conclusive statements about clinical significance could be made.

Increased postoperative glycemic variability is associated with increased mortality in diabetic patients undergoing hip arthroplasty for hip fracture.

Increased glycemic variability (GV) during hospitalization has been associated with increased rates of surgical site and periprosthetic joint infections (PJI) following elective total joint arthroplasty. Uncertainty exists surrounding GV as a predictor for complications in urgent arthroplasty cases following hip fractures. In this study, we evaluated the association between GV and postoperative complications in diabetic patients undergoing total hip arthroplasty (THA) and hemiarthroplasty (HA) for hip fractures. We analyzed data on 2421 consecutive patients who underwent THA or HA at our institution from 2011 to 2020. Patients with a known diagnosis of diabetes mellitus who had a minimum of three postoperative glucose values taken within the first week after surgery were included. GV was assessed using a coefficient of variation. Outcomes included short- and long-term mortality, reoperations, prosthetic joint infection (PJI) requiring revision and readmissions for any cause. The final cohort consisted of 482 patients (294 females, 188 males). Higher GV was associated with an increased 90-day mortality (p = 0.017). GV was not associated with 30-day mortality (p = 0.45), readmissions of any cause at 30 or 90days (p = 0.99, p = 0.91, respectively), reoperation of any cause (p = 0.91) or PJI requiring revision surgery (p = 0.42). Higher GV in the postoperative period is associated with increased rates of mortality in diabetic patients following THA and HA for hip fractures. Efforts should be made to monitor and control glucose variability in the postoperative period.

Limits of the precision in refractive results after cataract surgery

Background and objectiveIn order to improve refractive results in cataract surgery with an intraocular lens implant, it is important to know the sources of error as well as the limit of this process. Therefore, the objective of the present work is to approximate the theoretical limit in the precision in the refractive result after cataract surgery with the currently available means and to assess the impact of different sources of error in this process. Materials and methodsWe conducted a search of the literature to determine the variability provided by each component of the process. Based on the Barrett Universal-II formula, we performed an error propagation analysis. The theoretical limit was defined as the situation in which the refractive result is only affected by the variability in the parameters introduced in the formula, the tolerance of the intraocular lens and the subjective refraction. ResultsThe main contributors to the error were (1) intraoperative and postoperative variability variables not considered by the formulas (49.33%), (2) postoperative subjective refraction (38.29%), (3) mean keratometry (5.98%) and (4) the variability in the labelling of the power of the intraocular lens (5.09%). The theoretical limit obtained for the intraocular lens calculation with the means available today was 91.9% of the eyes between ±0.50D. ConclusionsWe found a theoretical limit for the intraocular lens calculation of 91.9% of the eyes between ±0.50D. Approaching the precision limit described in the study requires the use of optical biometrics and state-of-the-art formulas, a reproducible surgical technique, and the compensation of systematic errors by adjusting constants.

Límites de la precisión en el resultado refractivo tras la cirugía de cataratas

Background and objectiveIn order to improve refractive results in cataract surgery with an intraocular lens implant, it is important to know the sources of error as well as the limit of this process. Therefore, the objective of the present work is to approximate the theoretical limit in the precision in the refractive result after cataract surgery with the currently available means and to assess the impact of different sources of error in this process. Materials and methodsWe conducted a search of the literature to determine the variability provided by each component of the process. Based on the Barrett Universal-II formula, we performed an error propagation analysis. The theoretical limit was defined as the situation in which the refractive result is only affected by the variability in the parameters introduced in the formula, the tolerance of the intraocular lens and the subjective refraction. ResultsThe main contributors to the error were: 1. Intraoperative and postoperative variability variables not considered by the formulas (49.33%). 2. Postoperative subjective refraction (38.29%). 3. Mean keratometry (5.98%), and 4. the variability in the labelling of the power of the intraocular lens (5.09%). The theoretical limit obtained for the intraocular lens calculation with the means available today was 91.9% of the eyes between + -0.50D. ConclusionsWe found a theoretical limit for the intraocular lens calculation of 91.9% of the eyes between + -0.50D. Approaching the precision limit described in the study requires the use of optical biometrics and state-of-the-art formulas, a reproducible surgical technique, and the compensation of systematic errors by adjusting constants.

Six-year longitudinal prospective comparative study between preoperative and postoperative heart rate variability indices in congenital craniovertebral junction anomalies.

Craniovertebral junction (CVJ) anomalies involve mosaic interaction of multifaceted neurovascular and bony elements. Most of them present late in the course of illness usually as acute presentations following trivial trauma. Knowing subclinical autonomic dysfunction in such anomalies when managed medically can not only indicate progression but also provide en route to early intervention for better outcomes, especially in relatively asymptomatic patients. We conducted a 6-year longitudinal prospective study including 40 consecutive patients of CVJ anomalies with clinical, radiological, and heart rate variability (HRV) parameters and found their correlation in preoperative and follow-up period. Twenty-eight patients were male and the rest were female. The mean age was 32 years with the least age being 8 years and maximum age being 75 years old. Mean Nurick's grade and Barthel's index were 1.8 and 83.75, respectively. 38% had severe-to-moderate compression. The mean follow-up was 17.4 months. Both sympathetic and parasympathetic oscillator HRV indices were significantly affected in the preoperative period (P ≤ 0.001) with no association with Nurick's grade or degree of compression although there was association with grade of Barthel's index. Poincare plots showed "fan," "complex," or "torpedo" patterns in 36 patients. Forty patients had both preoperative and follow-up clinical grade whereas 22 patients HRV tests in the above periods. None of the HRV indices showed significant improvement at follow-up. Nonetheless both sympathetic and parasympathetic did improve at follow-up with sympathetic tone registering better scores. Poincare plots showed improvement toward "comet" patterns in all patients. HRV indices not only help in prognosticating but may also help in predicting outcomes.

Intraoperative blood pressure lability carries a higher risk of headache after carotid endarterectomy

ObjectiveCerebral hyperperfusion syndrome (CHS) is a rare but potentially devastating complication after carotid endarterectomies (CEA). Its symptoms range from new-onset unilateral headache (HA) to intracranial hemorrhage (ICH). Risk factors for CHS in the literature to date have not yet yielded a consensus. This study examines intraoperative and postoperative blood pressure variations as potential risk factors for HA. MethodsA single-center retrospective review at a tertiary care center from January 2010 to November 2019 was performed. Inclusion criteria were all patients undergoing CEA for symptomatic or asymptomatic carotid disease. Patients with incomplete charts were excluded. Primary endpoints were new-onset unilateral HA or postoperative ICH. Data on intraoperative and postoperative mean arterial pressure (MAP), systolic blood pressure (SBP), the mode of endarterectomy, shunt placement, and contralateral carotid status were collected. ResultsThere were 735 patients who met the inclusion criteria: 430 patients underwent modified eversion CEA (59%) and 305 patients for patch angioplasty (42%). The incidence of HA was 19% (n = 142) in our total cohort. Of the 19% with HA, 1.5% (n = 11) demonstrated no relief with analgesics and strict blood pressure control; noncontrast head computed tomography scans were performed subsequently. One patient (0.1%) had an ipsilateral ICH. Univariate analysis demonstrated that greater intraoperative MAP peak had the highest risk for HA (odds ratio [OR], 1.014; 95% confidence interval [CI], 1.007-1.022; P = .0002), followed by intraoperative MAP variability (OR, 1.011; 95% CI,1.005-1.018; P ≤ .0008), and peak intraoperative SBP (OR, 1.01; 95% CI, 1.004-1.015; P = .0011). An unpaired Student t test identified change in intraoperative MAP (P < .005), change in the SBP (P < .005), and peak SBP (P < .001) were significantly associated with HA. Interestingly, there was no significant difference between postoperative MAP variability and HA (P = .1). The mode of endarterectomy showed no statistically significant difference in risk for developing HA (OR, 1.165; 95%; 95% CI, 0.801-1.694; P = .42). ConclusionsGreater intraoperative variability in blood pressures are significantly associated with a higher risk of HA. Adhering to stricter intraoperative blood pressure parameters and limiting blood pressure variability may be beneficial at decreasing the incidence of CHS and its complications.

Postoperative Glycemic Variability as a Predictor of Adverse Outcomes Following Lumbar Fusion.

A retrospective cross-sectional study. This study aims to evaluate the effect size of postoperative glycemic variability on surgical outcomes among patients who have undergone one- to three-level lumbar fusion. While numerous patient characteristics have been associated with surgical outcomes after lumbar fusion, recent studies have described the measuring of postoperative glycemic variability as another promising marker. A total of 850 patients were stratified into tertiles (low, moderate, high) based on degree of postoperative glycemic variability defined by coefficient of variation (CV). Surgical site infections were determined via chart review based on the Centers for Disease Control and Prevention definition. Demographic factors, surgical characteristics, inpatient complications, readmissions, and reoperations were determined by chart review and telephone encounters. Overall, a statistically significant difference in 90-day adverse outcomes was observed when stratified by postoperative glycemic variability. In particular, patients with high CV had a higher odds ratio (OR) of readmission (OR = 2.19 [1.17, 4.09]; P = 0.01), experiencing a surgical site infection (OR = 3.22 [1.39, 7.45]; P = 0.01), and undergoing reoperations (OR = 2.65 [1.34, 5.23]; P = 0.01) compared with patients with low CV. No significant association was seen between low and moderate CV groups. Higher CV patients were more likely to experience longer hospital stays (β: 1.03; P = 0.01). Among the three groups, high CV group experienced the highest proportion of complications. Our study establishes a significant relationship between postoperative glycemic variability and inpatient complications, length of stay, and 90-day adverse outcomes. While HbA1c has classically been used as the principal marker to assess blood glucose control, our results show CV to be a strong predictor of postoperative adverse outcomes. Future high-quality, prospective studies are necessary to explore the true effect of CV, as well as its practicality in clinical practice. Nevertheless, fluctuations in blood glucose levels during the inpatient stay should be limited to improve patient results.Level of Evidence: 4.