Mechanisms for hypothermia during anaphylactic hypotension in awake rats

Hypothermia develops during systemic anaphylaxis in rodents. The aim of this study was to elucidate the mechanism for the hypothermia by assessing the roles of locomotor activity, tail heat dissipation, heat production in the brown adipose tissue (BAT) activity, and chemical mediators during ovalbumin-induced anaphylactic hypotension in awake rats. We measured the core body temperature (Tcore) and mean blood pressure (MBP), along with the surface temperature of the interscapular region (TiScap), an indirect measure of BAT activity, and the tail (Ttail). During anaphylaxis, MBP decreased to the nadir of 53 ± 2 mmHg at 8 min with recovery toward baseline. Tcore began to decrease at 7.5 min with the nadir of 36.1 ± 0.2°C at 30 min from the baseline of 38.0 ± 0.1°C. TiScap also significantly decreased, but its onset was preceded by that of Tcore. Ttail decreased after antigen, suggesting the absence of increased heat dissipation from the tail. The physical activity, as evaluated by moved distances, did not decrease until 20 min after antigen, followed by a progressive decrease. Reduced movement using a restraint maneuver not only reduced Tcore in nonsensitized rats but also augmented the anaphylactic hypothermia in the early phase (1.5-18 min) in sensitized rats. Combined antagonism against platelet-activating factor (PAF) and histamine H1 receptors abolished antigen-induced hypotension but only attenuated hypothermia. In conclusion, decreased locomotor activity, but not tail heat dissipation or decreased BAT activity, may at least in part contribute to this hypothermia. PAF and histamine are involved mainly in hypotension but only partly in hypothermia during rat anaphylaxis.NEW & NOTEWORTHY Anaphylactic shock is a life-threatening systemic hypotension. Hypothermia is observed during systemic anaphylaxis of rats. We determined the mechanism as follows: decreased locomotor activity, but not tail heat dissipation or decreased BAT activity, may at least in part contribute to this hypothermia. PAF and histamine are involved mainly in hypotension, but only partly in hypothermia during rat anaphylaxis.

Intraoperative hypotension in ambulatory surgery centers

STUDY OBJECTIVES

To measure the incidence of intraoperative hypotension (IOH) during surgery in ambulatory surgery centers (ASCs) and describe associated characteristics of patients and procedures.

DESIGN

Retrospective analysis.

SETTING

20 ASCs.

PATIENTS

16,750 patients having non-emergent, non-cardiac surgery; ASA physical status 2 through 4.

INTERVENTIONS

None.

MEASUREMENTS

We assessed incidence of IOH using the definition from the Centers for Medicare & Medicaid Services (CMS) Merit-based Incentive Payment System (MIPS)-mean arterial pressure (MAP) < 65 mmHg for at least 15 cumulative minutes-and three secondary definitions: minutes of MAP <65 mmHg, area under MAP of 65 mmHg, and time-weighted average MAP <65 mmHg.

MAIN RESULTS

30.9% of ASC cases had a MAP <65 mmHg for at least 15 min. The incidence of IOH varied significantly, and was higher among younger adults (age 18-39; 36.2%), females (35.2%), and patients with ASA physical status 2 (32.8%). IOH increased with increasing surgery length, even when time-weighted, and was higher among low complexity (30.6%) than moderate complexity (28.8%) procedures, and highest among high complexity procedures (44.1%).

CONCLUSIONS

There was substantial occurrence of IOH in ASCs, similar to that described in academic hospital settings in previous literature. We hypothesize that this may reflect clinician preference not to intervene in perceived healthy patients or assumptions about ability to tolerate lower blood pressures on behalf of these patients. Future research will determine whether IOH in ACSs is associated with adverse outcomes to the same extent as described in more complex hospital-based surgeries.

Calculation of effective dose of phenylephrine bolus for treatment of post-spinal hypotension in pre-eclamptic patients undergoing caesarean section - a non-randomised controlled trial

BACKGROUND

Patients with pre-eclampsia require smaller vasopressor doses compared with those with normotension for management of post-spinal hypotension during caesarean section. However, the literature has little evidence as to the phenylephrine dose required for patients with pre-eclampsia.

METHODS

Fifty patients, with either pre-eclampsia or normotension, and developing post-spinal hypotension during caesarean section under spinal anaesthesia, were studied. Women in both groups did not receive prophylactic vasopressors. The first patient in each group received phenylephrine 50 µg to treat the first episode of hypotension, defined as fall of systolic blood pressure ≥20% from baseline or an absolute value <100 mmHg. If hypotension was corrected within one minute it was considered a 'success'. The doses for the subsequent patients were determined by responses to all previous patients, according to a variation of Narayana's rule for the up-down sequential allocation method.

RESULTS

The 95% effective dose (ED95) and 50% effective dose (ED50) of phenylephrine was 41.7 µg (95% CI 33.8 to 49.6 µg) and 29.1 µg (95% CI 26.0 to 32.2 µg) respectively in the pre-eclampsia group, and 64.9 µg (95% CI 54.1 to 75.7 µg) and 47.3 µg (95% CI 39.7 to 54.9 µg) respectively in the normotensive group. The proportionate reduction in phenylephrine dose ranged from 33% (95% CI 18 to 44%) to 40% (95% CI 19 to 52%).

CONCLUSION

Patients with pre-eclampsia may need a 33% to 40% reduction in the first phenylephrine bolus dose, compared with patients with normotension, for the treatment of the first episode of post-spinal hypotension.

The Effect of Ketamine Versus Etomidate for Rapid Sequence Intubation on Maximum Sequential Organ Failure Assessment Score: A Randomized Clinical Trial

BACKGROUND

The use of induction agents for rapid sequence intubation (RSI) has been associated with hypotension in critically ill patients. Choice of induction agent may be important and the most commonly used agents are etomidate and ketamine.

OBJECTIVE

This study aimed to compare the effects of a single dose of ketamine vs. etomidate for RSI on maximum Sequential Organ Failure Assessment (SOFA) score and incidence of hypotension.

METHODS

This single-center, randomized, parallel-group trial compared the use of ketamine and etomidate for RSI in critically ill adult patients in the emergency department. The study was performed under Exception from Informed Consent. The primary outcome was the maximum SOFA score within 3 days of hospitalization.

RESULTS

A total of 143 patients were enrolled in the trial, 70 in the ketamine group and 73 in the etomidate group. Maximum median SOFA score for the ketamine group was 6.5 (interquartile range [IQR] 5-9) vs. 7 (IQR 5-9) for etomidate with no significant difference (-0.2; 95% CI -1.4 to 1.1; p = 0.79). The incidence of post-intubation hypotension was 28% in the ketamine group vs. 26% in the etomidate group (difference 2%; 95% CI -13% to 17%). There were no significant differences in intensive care unit outcomes. Thirty-day mortality rate for the ketamine group was 11% (8 deaths) and for the etomidate group was 21% (15 deaths), which was not statistically different.

CONCLUSIONS

There were no significant differences in maximum SOFA score or post-intubation hypotension between critically ill adults receiving ketamine vs. etomidate for RSI.

Real-time dual prediction of intradialytic hypotension and hypertension using an explainable deep learning model

Both intradialytic hypotension (IDH) and hypertension (IDHTN) are associated with poor outcomes in hemodialysis patients, but a model predicting dual outcomes in real-time has never been developed. Herein, we developed an explainable deep learning model with a sequence-to-sequence-based attention network to predict both of these events simultaneously. We retrieved 302,774 hemodialysis sessions from the electronic health records of 11,110 patients, and these sessions were split into training (70%), validation (10%), and test (20%) datasets through patient randomization. The outcomes were defined when nadir systolic blood pressure (BP) < 90 mmHg (termed IDH-1), a decrease in systolic BP ≥ 20 mmHg and/or a decrease in mean arterial pressure ≥ 10 mmHg (termed IDH-2), or an increase in systolic BP ≥ 10 mmHg (i.e., IDHTN) occurred within 1 h. We developed a temporal fusion transformer (TFT)-based model and compared its performance in the test dataset, including receiver operating characteristic curve (AUROC) and area under the precision-recall curves (AUPRC), with those of other machine learning models, such as recurrent neural network, light gradient boosting machine, random forest, and logistic regression. Among all models, the TFT-based model achieved the highest AUROCs of 0.953 (0.952-0.954), 0.892 (0.891-0.893), and 0.889 (0.888-0.890) in predicting IDH-1, IDH-2, and IDHTN, respectively. The AUPRCs in the TFT-based model for these outcomes were higher than the other models. The factors that contributed the most to the prediction were age and previous session, which were time-invariant variables, as well as systolic BP and elapsed time, which were time-varying variables. The present TFT-based model predicts both IDH and IDHTN in real time and offers explainable variable importance.

A case of successful hormone therapy for refractory hypotension following viral encephalitis: Case report

RATIONALE

Refractory hypotension is a life-threatening condition that can result from various causes. We report a rare case of refractory hypotension following herpes simplex virus type 1 encephalitis that was successfully treated with hormone therapy.

PATIENT CONCERNS

The patient was a 66-year-old male who was admitted to the hospital because of fever, chills, convulsions, and impaired consciousness. He developed respiratory failure and was intubated. Cerebrospinal fluid metagenomic sequencing confirmed herpes simplex virus type 1 infection. He received piperacillin-tazobactam for anti-infection, acyclovir for antiviral therapy, and dexamethasone for anti-inflammatory therapy. He had repeated episodes of hypotension despite fluid resuscitation and vasopressor therapy.

DIAGNOSIS

The diagnosis of herpes simplex virus type 1 encephalitis complicated by refractory hypotension was based on the patient's epidemiological history, clinical manifestations, laboratory tests, and imaging studies. Cerebrospinal fluid examination was the most important diagnostic method, which could detect viral nucleic acids. Head magnetic resonance imaging showed a large recent lesion in the right temporal-parietal and insular lobes.

INTERVENTIONS

The treatment of refractory hypotension mainly included anti-infection, antiviral, anti-inflammatory, and hormone therapy. Hormone therapy used methylprednisolone shock treatment until tapering withdrawal. Other treatments included fluid resuscitation, vasopressors, anticonvulsants, etc.

OUTCOMES

The patient's blood pressure stabilized after receiving methylprednisolone shock treatment, and his mean arterial pressure increased from 73 mm Hg to 92 mm Hg within 24 hours. Three months later, the patient's blood pressure was normal without medication, and he had a good social and physical recovery.

LESSONS

This case illustrates the possible role of hormone therapy in restoring blood pressure in patients with refractory hypotension following viral encephalitis. It suggests that adrenal insufficiency or autonomic dysfunction may be involved in the pathophysiology of this condition. Further studies are needed to confirm the efficacy and safety of hormone therapy in this setting.

[Risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants]

OBJECTIVES

To investigate the risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants.

METHODS

A retrospective analysis was conducted on clinical data of extremely preterm infants admitted to the Children's Hospital of Zhejiang University School of Medicine from January 2019 to April 2022. Based on the presence of hypotension within 72 hours after birth, the eligible infants were divided into a hypotension group (41 cases) and a normotension group (82 cases). The clinical characteristics, echocardiographic parameters within 72 hours after birth, and early complications were compared between the two groups. Multivariate logistic regression analysis was used to explore the risk factors for hypotension within 72 hours after birth, and receiver operating characteristic curve analysis was performed to evaluate the predictive value of relevant indicators for the occurrence of hypotension within 72 hours after birth in the preterm infants.

RESULTS

The proportion of infants who required medication or surgical closure of patent ductus arteriosus (PDA), the proportions of infants with intraventricular hemorrhage ≥ grade III and severe pulmonary hemorrhage, and the mortality rate within 7 days in the hypotension group were significantly higher than those in the normotension group (P<0.05). Multivariate logistic regression analysis showed that lower birth weight, larger PDA diameter, and hemodynamically significant PDA were risk factors for the occurrence of hypotension within 72 hours after birth in extremely preterm infants (P<0.05). The receiver operating characteristic curve analysis showed that the combination of birth weight, PDA diameter, and hemodynamically significant PDA had an area under the curve of 0.873 (95%CI: 0.802-0.944, P<0.05) for predicting hypotension within 72 hours after birth, with a sensitivity of 73.2% and specificity of 91.5%.

CONCLUSIONS

Hypotension within 72 hours after birth is closely related to birth weight and PDA, and increases the risk of early severe complications and mortality in extremely preterm infants.

Incorporating intraoperative blood pressure time-series variables to assist in prediction of acute kidney injury after type a acute aortic dissection repair: an interpretable machine learning model

BACKGROUND

Acute kidney injury (AKI) is a common and serious complication after the repair of Type A acute aortic dissection (TA-AAD). However, previous models have failed to account for the impact of blood pressure fluctuations on predictive performance. This study aims to develop machine learning (ML) models combined with intraoperative medicine and blood pressure time-series data to improve the accuracy of early prediction for postoperative AKI risk.

METHODS

Indicators reflecting the duration and depth of hypotension were obtained by analyzing continuous mean arterial pressure (MAP) monitored intraoperatively with multiple thresholds (<65, 60, 55, 50) set in the study. The predictive features were selected by logistic regression and the least absolute shrinkage and selection operator (LASSO), and 4 ML models were built based on the above features. The performance of the models was evaluated by area under receiver operating characteristic curve (AUROC), calibration curve and decision curve analysis (DCA). Shapley additive interpretation (SHAP) was used to explain the prediction models.

RESULTS

Among the indicators reflecting intraoperative hypotension, 65 mmHg showed a statistically superior difference to other thresholds in patients with or without AKI (p < .001). Among 4 models, the extreme gradient boosting (XGBoost) model demonstrated the highest AUROC: 0.800 (95% 0.683-0.917) and sensitivity: 0.717 in the testing set and was verified the best-performing model. The SHAP summary plot indicated that intraoperative urine output, cumulative time of mean arterial pressure lower than 65 mmHg outside cardiopulmonary bypass (OUT_CPB_MAP_65 time), autologous blood transfusion, and smoking were the top 4 features that contributed to the prediction model.

CONCLUSION

With the introduction of intraoperative blood pressure time-series variables, we have developed an interpretable XGBoost model that successfully achieve high accuracy in predicting the risk of AKI after TA-AAD repair, which might aid in the perioperative management of high-risk patients, particularly for intraoperative hemodynamic regulation.

Investigation of the relationship between intradialytic hypotension during hemodialysis and serum syndecan-1 concentration

Intradialytic hypotension and arrhythmias are complications of hemodialysis. They are associated with decreased intravascular volume due to reduced ultrafiltration volume, cardiac function, and arterial tone. The vascular endothelial glycocalyx, which exists on the surface of healthy vascular endothelial cells and maintains vascular permeability, has been suggested to be impaired by hemodialysis. This single-center retrospective study evaluated the association between syndecan-1, an endothelial glycocalyx dysfunction marker, and complications of hemodialysis. We enrolled 92 patients who underwent outpatient hemodialysis at Gifu Seiryu Hospital from April to July 2022 (346 hemodialysis sessions). The median duration and time of hemodialysis were 40 months and 4.1 h, respectively. Median serum syndecan-1 levels were 67.7 ng/mL before and 98.3 ng/mL after hemodialysis. Hemodialysis complications were noted in 68 sessions, all of which were hypotension. No correlation between pre-hemodialysis syndecan-1 levels and the incidence of complications was observed. However, a positive correlation between the amount of change in syndecan-1 levels before and after hemodialysis and the incidence of hemodialysis complications was noted. Conversely, syndecan-1 levels did not correlate with brain or atrial natriuretic peptides, suggesting that impairment of the vascular endothelial glycocalyx may be a possible cause of intradialytic hypotension and may be useful in preventing intradialytic hypotension.

Point of care transthoracic echocardiography for the prediction of post - spinal anesthesia hypotension in elderly patients with cardiac diseases and left ventricular dysfunction : Inferior vena cava and post-spinal anesthesia hypotension in elderly patients

In elderly patients with cardiac diseases, changes in cardiovascular physiology diminish cardiovascular reserve and predispose to hemodynamic instability after spinal anesthesia; hence, such patients could be at risk of postoperative complications. Additionally, transthoracic echocardiography (TTE) is used in clinical practice to evaluate cardiovascular hemodynamics. Therefore, we hypothesized that echocardiographic measurements could display significant diagnostic power in the prediction of post - spinal anesthesia hypotension in elderly patients with cardiac diseases and reduced left ventricular ejection fraction (LV-EF). Therefore, sixty-one elderly orthopedic-trauma patients were recruited. Prior to spinal anesthesia a TTE examination was performed. The LV-EF, the stroke volume index (SVI), the peripheral vascular resistance (PVR), the LV filling pressures (E/Em ratio), the right ventricular function [tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (TASV) and fractional area change (FAC)], as well as inferior vena cava (IVC) measurements, such as IVCCI (collapsibility index of the IVC) and dIVCmax (maximum diameter of IVC)-to-IVCCI ratio were assessed. Twenty-six out of sixty-one patients manifested hypotension. Preoperative dIVCmax-to-IVCCI ratio demonstrated the greatest performance amongst echocardiographic indices in predicting post - spinal anesthesia hypotension. The dIVCmax-to-IVCCI ratio < 48 had significantly higher diagnostic power than IVCCI > 0.28, FAC > 42, E/Em ratio < 9 and SVI < 32 (receiver operator characteristic curve analysis). The gray zone for the dIVCmax-to-IVCCI ratio (40-49) showed the lowest number of inconclusive measurements among echocardiographic variables. The preoperative dIVCmax-to-IVCCI ratio could be a reliable echocardiographic index to predict post - spinal anesthesia hypotension in elderly patients with left ventricular dysfunction.

Effect of preoperative risk on the association between intraoperative hypotension and postoperative acute kidney injury in cardiac surgery

BACKGROUND

Acute kidney injury (AKI), a common and severe complication after cardiac surgery, has been demonstrated to be associated with intraoperative hypotension (IOH). The reproducibility of this finding and whether preoperative risk modifies the association remain unclear. We hypothesised that the relationship between IOH and AKI after cardiac surgery varies by preoperative risk.

METHODS

We conducted a single-centre, retrospective cohort study to analyse the association between IOH and postoperative AKI by stratifying patients using preoperative risk factors. IOH was defined as a mean arterial pressure (MAP) of less than 65 mmHg and characterised by the cumulative duration and area under the curve (AUC).

RESULTS

Ten variables could be identified as risk factors: age, smoking status, NYHA III/Ⅳ, emergency surgery, peripheral vascular disease, cerebrovascular disease, heart failure, hypertension, previous cardiac surgery, and NT-proBNP concentration. The risk prediction model divided the patients into three equal-sized preoperative risk groups. Low-risk patients demonstrated no association between AKI and IOH of any severity, while high-risk patients demonstrated a statistically significant association between AKI and IOH with a cumulative duration greater than 104 min (adjusted odds ratio [OR]: 2.27, 95% confidence interval [CI]: 1.10-4.74; and adjusted OR: 3.63, 95% CI: 1.77-7.58) and an AUC greater than 905 mmHg min (adjusted OR: 2.08, 95% CI: 1.01-4.36; and adjusted OR: 4.00, 95% CI: 1.95-8.43).

CONCLUSION

IOH is a significant independent risk factor for AKI after cardiac surgery. Patients with higher baseline risk showed a more prominent relationship between IOH and postoperative AKI than low-risk patients.

Diagnostic Peritoneal Aspiration or Lavage in Stratified Groups of Hypotensive Blunt Trauma Patients

BACKGROUND

Some reports suggest Diagnostic peritoneal aspiration (DPA) or lavage (DPL) may better select which hypotensive blunt trauma patients (BTPs) require operation, compared to ultrasonography. However, whether both moderately hypotensive (systolic blood pressure [SBP] < 90 mmHg) and severely hypotensive (SBP < 70 mmHg) patients benefit from DPA/DPL is unclear. We hypothesized DPA/DPL used within the first hour increases risk of death for severely vs moderately hypotensive BTPs.

METHODS

The 2017-2019 Trauma Quality Improvement Program database was queried for BTPs ≥ 18 years old with hypotension upon arrival. We compared moderately and severely hypotensive groups. A multivariable logistic regression analysis was performed controlling for age, comorbidities, emergent operation, blood transfusions, and injury profile.

RESULTS

From 134 hypotensive patients undergoing DPA/DPL, 66 (49.3%) had severe hypotension. Patients in both groups underwent an emergent operation (43.9% vs 58.8%, P = .09) in a similar amount of time (median, 42-min vs 54-min, P = .11). Compared to the moderately hypotensive group, severely hypotensive patients had a higher rate and associated risk of death (84.8% vs 50.0%, P < .001) (OR 5.40, CI 2.07-14.11, P < .001). The strongest independent risk factor for death was age ≥ 65 (OR 24.81, CI 4.06-151.62, P < .001).

DISCUSSION

Among all BTPs undergoing DPA/DPL within the first hour of arrival, an over 5-fold increased risk of death for patients with severe hypotension was demonstrated. As such, DPA/DPL within this group should be used with caution, particularly for older patients, as they may be better served by immediate surgeries. Future prospective research is needed to confirm these findings and elucidate the ideal DPA/DPL population in the modern era of ultrasonography.

Adherence to Established Blood Pressure Targets and Associated Complications in Patients Presenting with Acute Intracerebral Hemorrhage

BACKGROUND

Conflicting evidence exists surrounding systolic blood pressure (SBP) control in patients with acute intracerebral hemorrhage (ICH). The 2022 American Heart Association and American Stroke Association guidelines recommend targeting a SBP of 140 mm Hg while maintaining the range of 130-150 mm Hg. The current practice at our health system is to titrate antihypertensives to a SBP goal of < 160 mm Hg, which aligns with previous recommendations. We hypothesized that the prior lack of guidance to a specific SBP target range predisposed patients to hypotension leading to an increased risk of brain and renal adverse events.

METHODS

This retrospective, multicenter, single health system cohort study included adults admitted to the neurointensive care unit or intermediate unit with acute ICH from June 2019 to June 2021. The primary objective evaluated the frequency of time within SBP range (140-160 mm Hg) in the first 48 h. Secondary and safety end points included the frequency of time above and below the established SBP range, episodes of hypotension (defined as a decrease in SBP < 140 mm Hg prompting discontinuation in antihypertensive[s] or the initiation of vasopressor[s]), the incidence of new brain or renal adverse events within 7 days, and modified Rankin Scale at discharge.

RESULTS

A total of 80 patients (59% men; median age 62 years) were included. The majority of ICHs in this cohort were intraparenchymal (70%). Nearly one third were attributed to systemic hypertension (31%). During the first 48 h of admission, the frequency of time spent above, within, and below the target SBP range were 6 h (12%), 16 h (34%), and 26 h (54%), respectively. Hypotension was associated with renal adverse events (odds ratio [OR] 3.36, 95% confidence interval [CI] 1.10-11.44, p = 0.023). A relative SBP reduction > 20% in the first 48 h was associated with renal adverse events (OR 8.99, 95% CI 2.57-35.25, p < 0.001), brain ischemia (OR 22.5, 95% CI 1.92-300.11, p = 0.005), and an increased odd of a modified Rankin Scale of 4-6 at discharge (OR 11.79, 95% CI 2.79-57.02, p < 0.001).

CONCLUSIONS

In individuals with nontraumatic/nonaneurysmal ICH, SBP measurements were observed to be < 140 mm Hg for > 50% of the initial 48 h following admission. Hypotension and relative SBP reduction > 20% were also independent predictors of renal adverse events. SBP reduction > 20% was also an independent predictor of brain ischemia. These data indicate that intensive SBP reduction following ICH predispose patients to secondary organ injury that may impact long-term outcomes. Our data suggest that a more modest lowering of the SBP within 48 h, as recommended in the most recent guidelines, may minimize the risk of further adverse events.

Development and validation of a nomogram for predicting intraoperative hypotension in cardiac valve replacement

Background: Cardiac valve replacement risks include intraoperative hypotension, endangering organ perfusion. Our nomogram predicted hypotension risk in valve surgery, guiding early intervention. Methods: Analyzing 561 patients from July to November 2022, we developed a nomogram to predict hypotension in valve replacement patients, validated using data from December 2022 to January 2023 on 241 patients, with robust statistical confirmation. Results: Our study identified age, hypertension, left ventricular ejection fraction and serum creatinine as hypotension predictors. The resulting nomogram, validated with high concordance index and area under the curve scores, provided a clinically useful tool for managing intraoperative risk. Conclusion: For valve replacement patients, factors like age, hypertension, low left ventricular ejection fraction and high serum creatinine predicted hypotension risk. Our nomogram enabled clinicians to quantify this risk and proactively manage it.

Time of hemodialysis and risk of intradialytic hypotension and intradialytic hypertension in maintenance hemodialysis

Intradialytic hypotension and intradialytic hypertension are complications of hemodialysis (HD) associated with a higher risk of cardiovascular disease (CVD) and death. Blood pressure (BP) normally fluctuates in a circadian pattern, but whether the risk of intradialytic hypotension and intradialytic hypertension varies according to the time of the HD session is unknown. We analyzed two cohorts of thrice-weekly maintenance HD (N = 1838 patients/n = 64,503 sessions from the Hemodialysis [HEMO] Study, and N = 3302 patients/n = 33,590 sessions from Satellite Healthcare). Random effects logistic regression models examined the association of HD start time (at or before 9:00 a.m. [early AM], between 9:01 a.m. and 12:00 p.m. [late AM], and at or after 12:01 p.m. [PM]) with intradialytic hypotension (defined as nadir intra-HD systolic BP (SBP) < 90 mmHg if pre-HD SBP < 160 mmHg, or <100 mmHg if pre-HD SBP ≥ 160 mmHg) and intradialytic hypertension (SBP increase ≥ 10 mmHg from pre-HD to post-HD). Compared to early AM, late AM and PM were associated with an 8% (aOR 0.92, 95% CI 0.83-1.02) and a 16% (aOR 0.84, 95% CI 0.75-0.95) lower risk of intradialytic hypotension in HEMO, respectively. Conversely, compared to early AM, a monotonic higher risk of intradialytic hypertension was observed for late AM (aOR 1.23, 95% CI 1.12-1.35) and PM (aOR 1.41, 95% CI 1.27-1.56) in HEMO. These findings were consistent in Satellite. In two large cohorts of maintenance HD, we observed a monotonic lower risk of intradialytic hypotension and a monotonic higher risk of intradialytic hypertension with later dialysis start times. Whether HD treatment allocation to certain times of the day in hypotensive-prone or hypertensive-prone patients improves outcomes deserves further investigation.

Characterization of Epidural Analgesia Interruption and Associated Outcomes After Esophagectomy

INTRODUCTION

Interruption of thoracic epidural analgesia may impact the postoperative course following esophagectomy. This study investigates the incidence and causes of epidural interruption in esophagectomy patients along with associated postoperative outcomes.

METHODS

This single-institution retrospective analysis examined patients undergoing esophagectomy who received a thoracic epidural catheter from 2016 to 2020. Patients were stratified according to whether epidural catheter infusion was interrupted or not postoperatively. Outcomes were compared between the two groups, and predictors of epidural interruption and postoperative complications were estimated using multivariable logistic regression.

RESULTS

Of the 168 patients who received a thoracic epidural before esophagectomy, 60 (35.7%) required epidural interruption and 108 (64.3%) did not. Interruption commonly occurred on postoperative day 1 and was due to hypotension 80% of the time. Heart failure (10.0% versus 0.9%, P = 0.009), atrial fibrillation (20.0% versus 3.7%, P = 0.002), preoperative opioid use (30.0% versus 16.7%, P = 0.043), and higher American Society of Anesthesiology classification (88.4% versus 70.4%, P = 0.008) were more prevalent in the epidural interruption cohort. The female gender was associated with epidural interruption on multivariable logistic regression (adjusted odds ratio [AOR] 2.45, P = 0.039). Patients in the epidural interruption cohort had a higher incidence of delirium (30.5% versus 13.9%, P = 0.010), sepsis (13.6% versus 3.7%, P = 0.028), and severe anastomotic leak (18.3% versus 7.4%, P = 0.032). On adjusted analysis, heart disease (AOR 4.26, P = 0.027), BMI <18.5 (AOR 9.83, P = 0.031), and epidural interruption due to hypotension (AOR 3.51, P = 0.037) were associated with severe anastomotic leak.

CONCLUSIONS

Early epidural interruption secondary to hypotension in esophagectomy patients may be a harbinger of postoperative complications such as sepsis and severe anastomotic leak. Patients requiring epidural interruption due to hypotension should have a low threshold for additional workup and early intervention.

Sedative Dose for Rapid Sequence Intubation and Postintubation Hypotension: Is There an Association?

STUDY OBJECTIVE

For patients with hemodynamic instability undergoing rapid sequence intubation, experts recommend reducing the sedative medication dose to minimize the risk of further hemodynamic deterioration. Scant data support this practice for etomidate and ketamine. We sought to determine if the dose of etomidate or ketamine was independently associated with postintubation hypotension.

METHODS

We analyzed data from the National Emergency Airway Registry from January 2016 to December 2018. Patients aged 14 years or older were included if the first intubation attempt was facilitated with etomidate or ketamine. We used multivariable modeling to determine whether drug dose in milligrams per kilogram of patient weight was independently associated with postintubation hypotension (systolic blood pressure < 100 mm Hg).

RESULTS

We analyzed 12,175 intubation encounters facilitated by etomidate and 1,849 facilitated by ketamine. The median drug doses were 0.28 mg/kg (interquartile range [IQR] 0.22 mg/kg to 0.32 mg/kg) for etomidate and 1.33 mg/kg (IQR 1 mg/kg to 1.8 mg/kg) for ketamine. Postintubation hypotension occurred in 1,976 patients (16.2%) who received etomidate and in 537 patients (29.0%) who received ketamine. In multivariable models, neither the etomidate dose (adjusted odds ratio [aOR] 0.95, 95% confidence interval [CI] 0.90 to 1.01) nor ketamine dose (aOR 0.97, 95% CI 0.81 to 1.17) was associated with postintubation hypotension. Results were similar in sensitivity analyses excluding patients with preintubation hypotension and including only patients intubated for shock.

CONCLUSION

In this large registry of patients intubated after receiving either etomidate or ketamine, we observed no association between the weight-based sedative dose and postintubation hypotension.