Intraoperative hypotension and neurological outcomes

Postinduction Hypotension and Adverse Outcomes in Older Adults Undergoing Transcatheter Aortic Valve Replacement: A Retrospective Cohort Study

Purpose

Postinduction hypotension (PIH), occurring between anaesthesia induction and surgical incision, is particularly concerning in older adults undergoing transcatheter aortic valve replacement (TAVR) due to their multiple comorbidities and age-related cardiovascular changes. This study aimed to assess the relationship between PIH and postoperative adverse events in TAVR patients.

Patients and Methods

A total of 777 patients underwent TAVR at The Second Affiliated Hospital of Zhejiang University School of Medicine from January 1, 2020 to February 28, 2023. Four thresholds of MAP were defined, including two absolute thresholds (<65, <60 mmHg) and two relative thresholds (20% and 30% lower than baseline). The relationships between PIH and the composite outcome, which included all-cause in-hospital mortality, stroke, acute kidney injury (AKI), and myocardial infarction (MI), were examined using unadjusted analysis, 1:1 propensity score matching(PSM), and inverse probability of treatment weighting (IPTW).

Results

A total of 643 older adults were included in the study ultimately. The composite outcome incidence was significantly greater in patients with PIH than in those without PIH (relative risk [RR]: 2.47, 95% CI: 1.66-3.73 for MAP <60 mmHg; RR: 1.66, 95% CI: 1.14-2.46 for a >30% decrease from baseline). PIH was significantly associated with stroke (RR: 5.22, 95% CI: 1.98-17.75) and AKI (RR: 2.82, 95% CI: 1.73-4.79) with a MAP <60 mmHg.

Conclusion

PIH significantly increases the risk of composite outcomes, especially stroke and AKI, in TAVR patients.

American society of anesthesiologists physical status classification significantly affects the performances of machine learning models in intraoperative hypotension inference

STUDY OBJECTIVE

To explore how American Society of Anesthesiologists (ASA) physical status classification affects different machine learning models in hypotension prediction and whether the prediction uncertainty could be quantified.

DESIGN

Observational Studies SETTING: UofL health hospital PATIENTS: This study involved 562 hysterectomy surgeries performed on patients (≥ 18 years) between June 2020 and July 2021.

INTERVENTIONS

None MEASUREMENTS: Preoperative and intraoperative data is collected. Three parametric machine learning models, including Bayesian generalized linear model (BGLM), Bayesian neural network (BNN), a newly proposed BNN with multivariate mixed responses (BNNMR), and one nonparametric model, Gaussian Process (GP), were explored to predict patients' diastolic and systolic blood pressures (continuous responses) and patients' hypotensive event (binary response) for the next five minutes. Data was separated into American Society of Anesthesiologists (ASA) physical status class 1- 4 before being read in by four machine learning models. Statistical analysis and models' constructions are performed in Python. Sensitivity, specificity, and the confidence/credible intervals were used to evaluate the prediction performance of each model for each ASA physical status class.

MAIN RESULTS

ASA physical status classes require distinct models to accurately predict intraoperative blood pressures and hypotensive events. Overall, high sensitivity (above 0.85) and low uncertainty can be achieved by all models for ASA class 4 patients. In contrast, models trained without controlling ASA classes yielded lower sensitivity (below 0.5) and larger uncertainty. Particularly, in terms of predicting binary hypotensive event, for ASA physical status class 1, BNNMR yields the highest sensitivity of 1. For classes 2 and 3, BNN has the highest sensitivity of 0.429 and 0.415, respectively. For class 4, BNNMR and GP are tied with the highest sensitivity of 0.857. On the other hand, the sensitivity is just 0.031, 0.429, 0.165 and 0.305 for BNNMR, BNN, GBLM and GP models respectively, when training data is not divided by ASA physical status classes. In terms of predicting systolic blood pressure, the GP regression yields the lowest root mean squared errors (RMSE) of 2.072, 7.539, 9.214 and 0.295 for ASA physical status classes 1, 2, 3 and 4, respectively, but a RMSE of 126.894 if model is trained without controlling the ASA physical status class. The RMSEs for other models are far higher. RMSEs are 2.175, 13.861, 17.560 and 22.426 for classes 1, 2, 3 and 4 respectively for the BGLM. In terms of predicting diastolic blood pressure, the GP regression yields the lowest RMSEs of 2.152, 6.573, 5.371 and 0.831 for ASA physical status classes 1, 2, 3 and 4, respectively; RMSE of 8.084 if model is trained without controlling the ASA physical status class. The RMSEs for other models are far higher. Finally, in terms of the width of the 95% confidence interval of the mean prediction for systolic and diastolic blood pressures, GP regression gives narrower confidence interval with much smaller margin of error across all four ASA physical status classes.

CONCLUSIONS

Different ASA physical status classes present different data distributions, and thus calls for distinct machine learning models to improve prediction accuracy and reduce predictive uncertainty. Uncertainty quantification enabled by Bayesian inference provides valuable information for clinicians as an additional metric to evaluate performance of machine learning models for medical decision making.

Hypotension during transsphenoidal pituitary surgery associated with increase in plasma levels of brain injury markers

BACKGROUND

Patients undergoing pituitary surgery may experience short- and long-term postoperative morbidity. Intraoperative factors such as hypotension might be a contributing factor. Our aim was to investigate the association between intraoperative hypotension and postoperative plasma levels of tau, neurofilament light (NfL), and glial fibrillary acidic protein (GFAP) as markers of perioperative brain injury.

METHODS

Between June 2016 and October 2017, 35 patients from the Gothenburg Pituitary Tumor Study were included. For tau, NfL, and GFAP, concentrations were measured in plasma samples collected before and immediately following surgery, and on postoperative days 1 and 5. The difference between the highest postoperative value and the value before surgery was used for analysis (∆taupeak , ∆NfLpeak , ∆GFAPpeak ). Intraoperative hypotension was defined as the area under the curve of an absolute threshold below 70 mmHg (AUC70) and a relative threshold below 20% (AUC20%) of the baseline mean arterial blood pressure.

RESULTS

Plasma tau and GFAP were highest immediately following surgery and on day 1, while NfL was highest on day 5. There was a positive correlation between AUC20% and both ∆taupeak (r2  = .20, p < .001) and ∆NfLpeak (r2  = .26, p < .001). No association was found between AUC20% and GFAP or between AUC70 and ∆taupeak , ∆NfLpeak or ∆GFAPpeak .

CONCLUSION

Intraoperative relative, but not absolute, hypotension was associated with increased postoperative plasma tau and NfL concentrations. Patients undergoing pituitary surgery may be vulnerable to relative hypotension, but this needs to be validated in future prospective studies.

Effect of remimazolam versus sevoflurane on intraoperative hemodynamics in noncardiac surgery: a retrospective observational study using propensity score matching

BACKGROUND

This study compared the effects of remimazolam and sevoflurane on intraoperative hemodynamics including intraoperative hypotension (IOH).

RESULTS

This study involved adult patients undergoing noncardiac surgery using remimazolam (Group R) or sevoflurane (Group S) for maintenance anesthesia, and invasive arterial pressure measurements, from September 2020 to March 2023 at our hospital. IOH was defined as a mean blood pressure < 65 mmHg occurring for a cumulative duration of at least 10 min. A 1:1 propensity score-matching method was used. The primary endpoint was the occurrence of IOH, and the secondary endpoints were the cumulative hypotensive time, incidence of vasopressor use, and dose of vasopressor used (ephedrine, phenylephrine, dopamine, and noradrenaline). Group R comprised 169 patients, Group S comprised 393 patients, and a matched cohort of 141 patients was created by propensity score matching. There was no significant difference in the incidence of IOH between the two groups (85.1% in Group R vs. 91.5% in Group S, p = 0.138). Patients in Group R had a significantly lower cumulative hypotension duration (55 [18-119] vs. 83 [39-144] min, p = 0.005), vasopressor use (81.6% vs. 91.5%, p = 0.023), and dose of ephedrine (4 [0-8] vs. 12 [4-20] mg, p < 0.001) than those in Group S. There were no significant differences in the doses of other vasopressors between groups.

CONCLUSIONS

Compared with sevoflurane, the maintenance of anesthesia with remimazolam was not associated with a decreased incidence of IOH; however, it reduced the cumulative hypotension time, incidence of vasopressor use, and dose of ephedrine.

Association of intraoperative hypotension and severe postoperative complications during non-cardiac surgery in adult patients: A systematic review and meta-analysis

Background

Intraoperative hypotension (IOH) is a common side effect of non-cardiac surgery that might induce poor postoperative outcomes. The relationship between the IOH and severe postoperative complications is still unclear. Thus, we summarized the existing literature to evaluate whether IOH contributes to developing severe postoperative complications during non-cardiac surgery.

Methods

We conducted a comprehensive search of PubMed, Embase, Cochrane Library, Web of Science, and the CBM from inception to 15 September 2022. The primary outcomes were 30-day mortality, acute kidney injury (AKI), major adverse cardiac events (myocardial injury or myocardial infarction), postoperative cognitive dysfunction (POCD), and postoperative delirium (POD). Secondary outcomes included surgical-site infection (SSI), stroke, and 1-year mortality.

Results

72 studies (3 randomized; 69 non-randomized) were included in this study. Low-quality evidence showed IOH resulted in an increased risk of 30-day mortality (OR, 1.85; 95% CI, 1.30-2.64; P < .001), AKI (OR, 2.69; 95% CI, 2.15-3.37; P < .001), and stroke (OR, 1.33; 95% CI, 1.21-1.46; P < .001) after non-cardiac surgery than non-IOH. Very low-quality evidence showed IOH was associated with a higher risk of myocardial injury (OR, 2.00; 95% CI, 1.17-3.43; P = .01), myocardial infarction (OR, 2.11; 95% CI, 1.41-3.16; P < .001), and POD (OR, 2.27; 95% CI, 1.53-3.38; P < .001). Very low-quality evidence showed IOH have a similar incidence of POCD (OR, 2.82; 95% CI, 0.83-9.50; P = .10) and 1-year-mortality (OR, 1.66; 95% CI, 0.65-4.20; P = .29) compared with non-IOH in non-cardiac surgery.

Conclusion

Our results suggest IOH was associated with an increased risk of severe postoperative complications after non-cardiac surgery than non-IOH. IOH is a potentially avoidable hazard that should be closely monitored during non-cardiac surgery.

Higher intraoperative mean arterial blood pressure does not reduce postoperative delirium in elderly patients following gastrointestinal surgery: A prospective randomized controlled trial

BACKGROUND

This study aimed to describe the relationship between the different levels of intraoperative mean arterial blood pressure (MAP) and postoperative delirium in elderly patients undergoing gastrointestinal laparoscopic surgery.

MATERIALS AND METHODS

This prospective controlled clinical trial enrolled 116 patients aged 65 to 85 years who underwent gastrointestinal laparoscopic surgery. These patients were randomized 1:1 to a MAP goal of 65 to 85 mmHg (L group) or an 86 to 100 mmHg (H group). The primary endpoint was the incidence of postoperative delirium, assessed twice daily with the Confusion Assessment Method (CAM) and Richmond Agitation-Sedation Scale (RASS) during the first five postoperative days. Delirium severity was evaluated with the Delirium-O-Meter (D-O-M).

RESULTS

108 patients (L group n = 55, H group n = 53) were eventually included in intention-to-treat analyses. Postoperative delirium occurred in 18 (32.7%) of 55 cases of L group and in 15 (28.3%) of 53 cases of H group. The incidence of delirium subtypes between the two groups: hypoactive delirium 14.5% (8/55) vs 11.3% (6/53); hyperactive delirium 7.3% (4/55) vs 3.8% (2/53); mixed delirium 10.9% (6/55) vs 13.2% (7/53). However, the L group showed higher D-O-M scores of the first episode of delirium: 14.5 (Q1 = 12, Q3 = 18.5) vs 12 (Q1 = 10, Q3 = 14), which means the delirium is more severe.

CONCLUSIONS

Compared with 65 to 85 mmHg, maintaining intraoperative MAP at 86-100 mmHg did not reduce the incidence of postoperative delirium in elderly patients undergoing gastrointestinal laparoscopic surgery. However, the severity of delirium could be reduced and blood loss is a risk factor for postoperative delirium.

Effect of combined use of cerebral oximetry and electroencephalogram monitoring on the incidence of perioperative neurocognitive disorders in adult cardiac and non-cardiac surgery: A systematic review of randomized and non-randomized trials

Background: There is insufficient evidence to recommend using either intraoperative cerebral oximetry or (processed) electroencephalogram (EEG) alone for preventing perioperative neurocognitive disorders (PNDs). Objective: To evaluate the effectiveness of combined use of cerebral oximetry and electroencephalogram-guided anesthesia on the incidence of PNDs in adult patients undergoing cardiac and non-cardiac interventions. Methods: A PICOS - based systematic review of English articles using Pubmed and Embase (from inception to August 2022) was performed. There were no exclusion criteria regarding the type of the study. Abstract proceedings and new study protocols or ongoing studies were not included. Review articles were analyzed in search of eligible references. All possible terms that were illustrative of PNDs were used. Results: Among the 63 full manuscripts that were analyzed in detail, 15 met the inclusion criteria. We found 2 retrospective, 8 prospective observational and 5 randomized controlled trials of which 1 did not evaluate the use of neuromonitoring in the randomization process. The definition and the methods used to diagnose PNDs were very heterogeneous. Only 8 studies used an algorithm to avoid/treat cerebral oxygen desaturation and/or to treat EEG abnormalities. Overall, there was a tendency towards less PNDs in studies where such an algorithm was used. Conclusions: Our results suggest that integrating information obtained from cerebral oximetry and an EEG monitor may reduce the incidence of PNDs whenever an adapted algorithm is used to improve brain function.

Impact of combined epidural anaesthesia/analgesia on postoperative cognitive impairment in patients receiving general anaesthesia: a meta-analysis of randomised controlled studies

BACKGROUND

To investigate the efficacy of combined epidural anaesthesia/analgesia (EAA) against postoperative delirium/cognitive dysfunction (POD/POCD) in adults after major non-cardiac surgery under general anaesthesia (GA).

METHODS

The databases of PubMed, Google scholar, Embase and Cochrane Central Register were searched from inception to November 2021 for available randomised controlled trials (RCTs) that assessed the impact of EAA on risk of POD/POCD. The primary outcome was risk of POD/POCD, while the secondary outcomes comprised postoperative pain score, length of hospital stay (LOS), risk of complications, and postoperative nausea/vomiting (PONV).

RESULTS

Meta-analysis of eight studies with a total of 2376 patients (EAA group: 1189 patients; non-EAA group: 1187 patients) revealed no difference in risk of POD/POCD between the EAA and the non-EAA groups [Risk ratio (RR): 0.68; 95% CI: 0.41 to 1.13, p = 0.14, I² = 73%], but the certainty of evidence was very low. Nevertheless, the EAA group had lower pain score at postoperative 24 h [mean difference (MD): -1.49, 95% CI: -2.38 to -0.61; I² = 98%; five RCTs; n = 476] and risk of PONV (RR = 0.73, 95% CI: 0.57 to 0.93, p = 0.01, I² = 0%; three RCTs, 1876 patients) than those in the non-EAA group. Our results showed no significant impact of EAA on the pain score at postoperative 36-72 h, LOS, and risk of complications.

CONCLUSION

This meta-analysis demonstrated that EAA had no significant impact on the incidence of POD/POCD in patients following non-cardiac surgery.

Recent advances and perspectives of postoperative neurological disorders in the elderly surgical patients

Postoperative neurological disorders, including postoperative delirium (POD), postoperative cognitive dysfunction (POCD), postoperative covert ischemic stroke, and hemorrhagic stroke, are challenging clinical problems in the emerging aged surgical population. These disorders can deteriorate functional outcomes and long‐term quality of life after surgery, resulting in a substantial social and financial burden to the family and society. Understanding predisposing and precipitating factors may promote individualized preventive treatment for each disorder, as several risk factors are modifiable. Besides prevention, timely identification and treatment of etiologies and symptoms can contribute to better recovery from postoperative neurological disorders and lower risk of long‐term cognitive impairment, disability, and even death. Herein, we summarize the diagnosis, risk factors, prevention, and treatment of these postoperative complications, with emphasis on recent advances and perspectives.

Perioperative renal protection

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common but underestimated syndrome in the perioperative setting. AKI can be induced by different causes and is associated with increased morbidity and mortality. Unfortunately, no specific treatment options are available at the moment.

RECENT FINDINGS

AKI is now understood as being a continuum ranging from normal kidney function over AKI and acute kidney disease to ultimately chronic kidney disease. The KDIGO organization recommend in 2012 implementation of preventive bundles in patients at high risk for AKI. In the perioperative setting, relevant measures include hemodynamic optimization, with careful consideration of blood pressure targets, adequate fluid therapy to maintain organ perfusion and avoidance of hyperglycaemia. These measures are most effective if patients at risk are identified as soon as possible and measures are implemented accordingly. Although current point of care functional biomarkers can detect patients at risk earlier than the established damage biomarkers, some components of the preventive bundle are still under investigation.

SUMMARY

Good evidence exists for the use of biomarkers to identify individual patients at risk for AKI and for the implementation of haemodynamic optimization, abdication of nephrotoxins, adequate fluid administration using balanced crystalloid solutions and glycaemic control. The data for using colloids or the degree of nephrotoxicity of contrast media still remain inconclusive.

Association of 5-aminolevulinic acid with intraoperative hypotension in malignant glioma surgery

BACKGROUND

Use of 5-aminolevulinic acid for photodynamic malignant tumor diagnosis reportedly causes intraoperative hypotension (systolic blood pressure < 70 mmHg) during urologic surgery. However, its association with intraoperative hypotension in malignant glioma surgery and underlying mechanisms has not yet been elucidated.. This study aimed to investigate whether 5-aminolevulinic acid administration is associated with intraoperative hypotension in malignant glioma surgery and explore the mechanisms of 5-aminolevulinic acid-induced hypotension in vitro.

METHODS

In this retrospective multicenter cohort study, we investigated intracellular nitric oxide as a candidate mediator of hypotension in response to 5-aminolevulinic acid in vitro in human umbilical vein endothelial cell cultures.

RESULTS

Of 142 patients, 94 underwent 5-aminolevulinic acid-guided surgery. Systolic blood pressure was significantly lower throughout surgery with 5-aminolevulinic acid administration. 5-Aminolevulinic acid administration was an independent risk factor for intraoperative hypotension according to multivariable logistic regression analysis (89% vs. 56%; odds ratio = 6.72, 95% confidence interval [2.05-22.1], P = 002). In subgroup analysis of the 5-aminolevulinic acid group, increasing age and use of renin-angiotensin system inhibitors had a synergistic effect with 5-aminolevulinic acid on decreased blood pressure. In the vascular endothelial cell culture study, 5-aminolevulinic acid induced a significant increase in intracellular nitric oxide generation.

CONCLUSIONS

5-Aminolevulinic acid administration was associated with intraoperative hypotension in malignant glioma surgery, with increasing age and use of renin-angiotensin system inhibitors boosting the blood pressure-lowering effect of 5-aminolevulinic acid. According to in vitro results, the low blood pressure induced by 5-aminolevulinic acid may be mediated by a nitric oxide increase in vascular endothelial cells.

Association between perioperative hypotension and postoperative delirium and atrial fibrillation after cardiac surgery: A post-hoc analysis of the DECADE trial

STUDY OBJECTIVE

To test the hypotheses that in adults having cardiac surgery with cardio-pulmonary bypass, perioperative hypotension increases the risk of delirium and atrial fibrillation during the initial five postoperative days.

DESIGN

Sub-analysis of the DECADE multi-center randomized trial.

SETTING

Patients who had cardiac surgery with cardiopulmonary bypass at the Cleveland Clinic.

INTERVENTIONS

In the underlying trial, patients were randomly assigned 1:1 to dexmedetomidine or normal saline placebo.

MEASUREMENTS

Intraoperative mean arterial pressures were recorded at 1-min intervals from arterial catheters or at 1-5-min intervals oscillometrically. Postoperative blood pressures were recorded every half-hour or more often. The co-primary outcomes were atrial fibrillation and delirium occurring between intensive care unit admission and the earlier of postoperative day 5 or hospital discharge. Delirium was assessed twice daily during the initial 5 postoperative days while patients remained hospitalized with the Confusion Assessment Method for the intensive care unit. Assessments were made by trained research fellows who were blinded to the dexmedetomidine administration.

MAIN RESULTS

There was no significant association between intraoperative hypotension and delirium, with an adjusted odds ratio of 0.94 (95% CI: 0.81, 1.09; P = 0.419) for a doubling in AUC of mean arterial pressure (MAP) <60 mmHg. An increase in intraoperative AUC of MAP <60 mmHg was not significantly associated with the odds of atrial fibrillation (adjusted odds ratio = 0.99; 95% CI: 0.87, 1.11; P = 0.819). Postoperative MAP <70 mmHg per hour 1.14 (97.5% CI: 1.04,1.26; P = 0.002) and MAP <80 mmHg per hour 1.05 (97.5%: 1.01, 1.10; P = 0.010) were significantly associated with atrial fibrillation.

CONCLUSIONS

In patients having cardiac surgery with cardio-pulmonary bypass, neither intraoperative nor postoperative hypotension were associated with delirium. Postoperative hypotension was associated with atrial fibrillation, although intraoperative hypotension was not.

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

Background: Deliberate hypotension can reduce bleeding and improve visualization of the surgical field during functional endoscopic sinus surgery (FESS). However, hypotension may cause brain hypoperfusion and subsequent ischemic injuries, such as delayed awakening, stroke, postoperative delirium, and postoperative cognitive dysfunction. Near-infrared spectroscopy (NIRS) can be used to monitor real-time regional cerebral oxygen saturation (rSO₂) levels to estimate brain perfusion. The present study aimed to evaluate the change in rSO₂ induced by deliberate hypotension during FESS, and assess the impact of deliberate hypotension on the surgical process.

Material and Methods: A randomized controlled trial was registered with the Chinese clinical trial registry (ChiCTR2000039846). A total of 40 patients were enrolled and randomly divided into the control and intervention groups, and finally, 39 patients were analyzed. Deliberate hypotension was induced in the intervention group using nicardipine and esmolol, whereas the control group received general anesthesia without deliberate hypotension. We recorded mean arterial pressure (MAP), saturation of pulse oximetry (SpO₂), rSO₂, and heart rate (HR) before induction of anesthesia (T0), immediately after induction of anesthesia (T1), at the beginning of the operation (corresponding with the establishment of deliberate hypotension) (T2), 10 min (T3) and 20 min (T4) after the operation began, at the end of the operation (corresponding with the end of deliberate hypotension) (T5), and 5 min (T6) and 15 min (T7) after the operation. The partial pressure of end-tidal carbon dioxide (PetCO₂) was recorded at T1, T2, T3, T4, T5, and T6. The duration of surgery, intraoperative blood loss, tracheal extubation time, and the number of patients that experienced cerebral desaturation events (CDEs) were recorded. The surgical field was estimated postoperation based on the Fromme score.

Results: A 30% decrease from the baseline MAP resulted in a decrease of intraoperative bleeding, improvement in the quality of the surgical field, and the shortening of the duration of surgery during FESS in the intervention group compared with the control group. In addition, rSO₂ was reduced and no CDEs were experienced in the intervention group. Linear regression analysis demonstrated a correlation between the decline in rSO₂ and that in MAP.

Conclusions: A decrease in MAP to a certain level will cause a decrease of rSO₂ in patients undergoing FESS under general anesthesia. Based on our findings, we recommend that the deliberate hypotensive target indicated by MAP be reduced by 30%, while PetCO₂ is maintained at 35–40 mmHg and HR is maintained at about 60 beats per minute during FESS.

Association Between Intraoperative Arterial Hypotension and Postoperative Delirium After Noncardiac Surgery: A Retrospective Multicenter Cohort Study

BACKGROUND

It is unclear whether intraoperative arterial hypotension is associated with postoperative delirium. We hypothesized that intraoperative hypotension within a range frequently observed in clinical practice is associated with increased odds of delirium after surgery.

METHODS

Adult noncardiac surgical patients undergoing general anesthesia at 2 academic medical centers between 2005 and 2017 were included in this retrospective cohort study. The primary exposure was intraoperative hypotension, defined as the cumulative duration of an intraoperative mean arterial pressure (MAP) <55 mm Hg, categorized into and short (<15 minutes; median [interquartile range {IQR}], 2 [1-4] minutes) and prolonged (≥15 minutes; median [IQR], 21 [17-31] minutes) durations of intraoperative hypotension. The primary outcome was a new diagnosis of delirium within 30 days after surgery. In secondary analyses, we assessed the association between a MAP decrease of >30% from baseline and postoperative delirium. Multivariable logistic regression adjusted for patient- and procedure-related factors, including demographics, comorbidities, and markers of procedural severity, was used.

RESULTS

Among 316,717 included surgical patients, 2183 (0.7%) were diagnosed with delirium within 30 days after surgery; 41.7% and 2.6% of patients had a MAP <55 mm Hg for a short and a prolonged duration, respectively. A MAP <55 mm Hg was associated with postoperative delirium compared to no hypotension (short duration of MAP <55 mm Hg: adjusted odds ratio [ORadj], 1.22; 95% confidence interval [CI], 1.11-1.33; P < .001 and prolonged duration of MAP <55 mm Hg: ORadj, 1.57; 95% CI, 1.27-1.94; P < .001). Compared to a short duration of a MAP <55 mm Hg, a prolonged duration of a MAP <55 mm Hg was associated with greater odds of postoperative delirium (ORadj, 1.29; 95% CI, 1.05-1.58; P = .016). The association between intraoperative hypotension and postoperative delirium was duration-dependent (ORadj for every 10 cumulative minutes of MAP <55 mm Hg: 1.06; 95% CI, 1.02-1.09; P =.001) and magnified in patients who underwent surgeries of longer duration (P for interaction = .046; MAP <55 mm Hg versus no MAP <55 mm Hg in patients undergoing surgery of >3 hours: ORadj, 1.40; 95% CI, 1.23-1.61; P < .001). A MAP decrease of >30% from baseline was not associated with postoperative delirium compared to no hypotension, also when additionally adjusted for the cumulative duration of a MAP <55 mm Hg (short duration of MAP decrease >30%: ORadj, 1.13; 95% CI, 0.91-1.40; P = .262 and prolonged duration of MAP decrease >30%: ORadj, 1.19; 95% CI, 0.95-1.49; P = .141).

CONCLUSIONS

In patients undergoing noncardiac surgery, a MAP <55 mm Hg was associated with a duration-dependent increase in odds of postoperative delirium. This association was magnified in patients who underwent surgery of long duration.

Safety, efficacy, and cost-performance of a simplified cryoballoon ablation procedure for paroxysmal atrial fibrillation

BACKGROUND

The search for a less invasive and lower cost cryoballoon-based strategy for atrial fibrillation (AF) ablation has resulted in a simplified procedure that may be suitable for cryoballoon ablation (CBA). Here, we compared procedural characteristics and outcomes between conventional CBA and simple CBA.

METHODS

We enrolled 628 consecutive patients who underwent initial CBA for AF (age, 69 ± 12 years; female, 263 (42%); paroxysmal AF, 576 (92%); CHA₂DS₂-VASc score, 2.7 ± 1.6 points). Simple CBA was characterized by the minimal procedure required to isolate pulmonary veins, including the following: (1) CBA was performed without guidance from a 3-D mapping system; (2) a coronary sinus electrode and esophageal temperature probe were not used; (3) a waiting period after pulmonary vein isolation was not set; and AF induction by isoproterenol and atrial burst stimuli were not performed.

RESULTS

Simple CBA was performed in 240 (38%) patients. Procedural time (49 ± 18 versus 85 ± 27 min, p < 0.01) was shorter, and total procedural costs (20,699 ± 8,091 versus 30,350 ± 11,647 US dollars, p < 0.01) were lower with simple CBA than conventional CBA. Freedom from AF recurrence during the 12-month study period (79.8% versus 78.4%, p = 0.52) and complication rate (8.8% versus 13.1%, p = 0.09) were similar between the two groups.

CONCLUSION

Compared with conventional CBA, simple CBA reduced procedural time and procedural costs while providing comparable outcomes.

Effect of Intraoperative Arterial Hypotension on the Risk of Perioperative Stroke After Noncardiac Surgery: A Retrospective Multicenter Cohort Study

BACKGROUND

Intraoperative cerebral blood flow is mainly determined by cerebral perfusion pressure and cerebral autoregulation of vasomotor tone. About 1% of patients undergoing noncardiac surgery develop ischemic stroke. We hypothesized that intraoperative hypotension within a range frequently observed in clinical practice is associated with an increased risk of perioperative ischemic stroke within 7 days after surgery.

METHODS

Adult noncardiac surgical patients undergoing general anesthesia at Beth Israel Deaconess Medical Center and Massachusetts General Hospital between 2005 and 2017 were included in this retrospective cohort study. The primary exposure was intraoperative hypotension, defined as a decrease in mean arterial pressure (MAP) below 55 mm Hg, categorized into no intraoperative hypotension, short (<15 minutes, median [interquartile range {IQR}], 2 minutes [1-5 minutes]) and prolonged (≥15 minutes, median [IQR], 21 minutes [17-31 minutes]) durations. The primary outcome was a new diagnosis of early perioperative ischemic stroke within 7 days after surgery. In secondary analyses, we assessed the effect of a MAP decrease by >30% from baseline on perioperative stroke. Analyses were adjusted for the preoperative STRoke After Surgery (STRAS) prediction score, work relative value units, and duration of surgery.

RESULTS

Among 358,391 included patients, a total of 1553 (0.4%) experienced an early perioperative ischemic stroke. About 42% and 3% of patients had a MAP of below 55 mm Hg for a short and a prolonged duration, and 49% and 29% had a MAP decrease by >30% from baseline for a short and a prolonged duration, respectively. In an adjusted analysis, neither a MAP <55 mm Hg (short duration: adjusted odds ratio [ORadj], 0.95; 95% confidence interval [CI], 0.85-1.07; P = .417 and prolonged duration: ORadj, 1.18; 95% CI, 0.91-1.55; P = .220) nor a MAP decrease >30% (short duration: ORadj, 0.97; 95% CI, 0.67-1.42; P = .883 and prolonged duration: ORadj, 1.30; 95% CI, 0.89-1.90; P = .176) was associated with early perioperative stroke. A high a priori stroke risk quantified based on preoperatively available risk factors (STRAS prediction score) was associated with longer intraoperative hypotension (adjusted incidence rate ratio, 1.04; 95% CI, 1.04-1.05; P < .001 per 5 points of the STRAS prediction score).

CONCLUSIONS

This study found no evidence to conclude that intraoperative hypotension within the range studied was associated with early perioperative stroke within 7 days after surgery. These findings emphasize the importance of perioperative cerebral blood flow autoregulation to prevent ischemic stroke.

How new biomarkers aid the anesthetist to detect and prevent perioperative acute kidney injury

PURPOSE OF REVIEW

Acute kidney injury (AKI) is underestimated but common in the perioperative setting. Although the association of this syndrome with an increased morbidity and mortality has been well established, little progress has been made in the diagnosis or prevention of AKI in recent years. This is partly due to the late detection of AKI by conventional criteria based of functional biomarkers, serum creatinine, and urine output. In addition, conceptually AKI is now recognized as being part of a continuum, in which preventive intervention is time critical. This review will summarize the current best available evidence and explain why timely perioperative management does have impact on the development of AKI and overall outcomes for patients.

RECENT FINDINGS

Damage biomarkers can reliably identify AKI earlier than conventional functional biomarkers, facilitating more timely preventive intervention. Although the interventions published in the Kidney Disease: Improving Global Outcomes guideline are all important, the most relevant preventive options perioperatively include maintenance of adequate volume status and perfusion pressure, and the focus on balanced crystalloid solutions as maintenance fluid.

SUMMARY

AKI is a time critical syndrome that requires timely detection and damage biomarkers can help to adjust the perioperative management to prevent further injury.

Postoperative delirium - treatment and prevention

PURPOSE OF REVIEW

Postoperative delirium (POD) is one of the most severe complications after surgery.The consequences are dramatic: longer hospitalization, a doubling of mortality and almost all cases develop permanent, yet subtle, cognitive deficits specific to everyday life. Actually, no global guideline with standardized concepts of management exists. Advances in prevention, diagnosis and treatment can improve recognition and risk stratification of delirium and its consequences.

RECENT FINDINGS

Management of POD is a multiprofessional approach and consists of different parts: First, the detection of high-risk patients with a validated tool, preventive nonpharmacological concepts and an intraoperative anesthetic management plan that is individualized to the older patient (e.g. avoiding large swings in blood pressure, vigilance in maintaining normothermia, ensuring adequate analgesia and monitoring of anesthetic depth). In addition to preventive standards, treatment and diagnostic concepts must also be available, both pharmaceutical and nonpharmacological.

SUMMARY

Not every POD can be prevented. It is important to detect patients with high risk for POD and have standardized concepts of management. The most important predisposing risk factors are a higher age, preexisting cognitive deficits, multimorbidity and an associated prodelirious polypharmacy. In view of demographic change, the implementation of multidisciplinary approaches to pharmacological and nonpharmacological POD management is highly recommended.