Dose-dependent relationship between intra-procedural hypoxaemia or hypocapnia and postoperative delirium in older patients

Association Between Neuromuscular Blockade and Its Reversal With Postoperative Delirium in Older Patients: A Hospital Registry Study

BACKGROUND

Nondepolarizing neuromuscular blocking agents (ND-NMBAs) are dose-dependently associated with residual paralysis, delayed recovery, and prolonged hospitalization, factors that can predispose patients to postoperative delirium. We hypothesized that neuromuscular blockade is associated with a higher risk of delirium after surgery, and that this can be mitigated by administration of reversal agents.

METHODS

In total, 53,772 adult hospitalized patients aged ≥60 years who underwent general anesthesia for noncardiac, nonneurosurgical, nontransplant procedures between 2008 and 2024 at a tertiary health care network in Massachusetts, were included. The exposure was the intraoperative administration of ND-NMBAs. The primary outcome was 7-day delirium, identified from nursing and physician charts using a keyword-based search strategy paired with manual chart review, Confusion Assessment Method assessments, and International Classification of Diseases (9th/10th Revision, Clinical Modification) diagnostic codes.

RESULTS

In total, 43,723 (81.3%) patients received neuromuscular blockade. Approximately 2259 (4.2%) patients developed delirium, 1884 (4.3%) with, and 375 (3.7%) without ND-NMBA administration. In adjusted analyses, administration of ND-NMBAs was dose-dependently associated with a higher risk of postoperative delirium (adjusted odds ratio [ORadj] 1.15; 95% confidence interval [CI], 1.01-1.31; P = .038 and 1.09; 95% CI, 1.06-1.12; P < .001 per each unit increase in the effective dose required to achieve a 95% twitch reduction). 38,143 (87.2%) patients who received ND-NMBAs also received a reversal agent, which was associated with a lower risk of impaired neuromuscular recovery (preextubation train-of-four ratio <95; ORadj 0.60; 95% CI, 0.49-0.74; P < .001) and delirium (ORadj 0.73; 95% CI, 0.64-0.83; P < .001), compared to no reversal. The adverse effect of ND-NMBAs on delirium risk was eliminated by reversal agent administration (ORadj 1.07; 95% CI, 0.94-1.23; P = .30 with and ORadj 1.52; 95% CI, 1.28-1.79; P < .001 without reversal agent administration). There was no association between administration of neostigmine, compared to sugammadex, with postoperative delirium (ORadj 0.91; 95% CI, 0.73-1.12; P = .36).

CONCLUSIONS

Neuromuscular blockade during general anesthesia is dose-dependently associated with a higher risk of postoperative delirium. The administration of reversal agents mitigates this risk and might help reduce the occurrence of delirium after surgery.

The effect of neuromuscular blocking reversal agents on perioperative neurocognitive function after general anaesthesia: a systematic review and meta-analysis

BACKGROUND

Perioperative neurocognitive dysfunction (PND) is influenced by various perioperative factors. Recent studies suggest that neuromuscular blocking reversal agents (NMBRs) may impact on PND. However, the results have been inconsistent. Therefore, we aimed to compare the effects of perioperative NMBRs on PND through this systematic review and meta-analysis.

METHODS

We searched PubMed, CENTRAL, Embase, Web of Science, Scopus, and China Biology Medicine from their inception until May 2024. Two reviewers independently identified randomized controlled trials (RCTs) that compared the perioperative use of NMBRs with either a placebo or other NMBRs in patients undergoing general anaesthesia. We assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The primary outcome was the incidence of PND within 7 days following surgery, while the secondary outcomes included the time required to achieve a Train-of-Four ratio (TOF) ≥ 0.9 after administration of NMBRs, length of stay (LOS) in both the post-anaesthesia care unit (PACU) and the hospital, as well as the risk of adverse events (i.e. postoperative nausea and vomiting (PONV) and mortality).

RESULTS

A total of 10 randomized controlled trials involving 1705 patients compared the effects of NMBRs on PND. Neostigmine and sugammadex are the most commonly used NMBRs in clinical anaesthesia practice. In the primary analyses of all regimens, sugammadex significantly reduced the incidence of PND compared to neostigmine (risk ratio [RR] 0.67; 95% confidence interval [CI]:0.48-0.94; I2 = 0%; P = 0.02; moderate quality). However, the results indicated that there is no significant association between neostigmine and PND when compared to placebo (RR 0.76; 95% CI: 0.55-1.05; I2 = 35%; P = 0.09; moderate quality). The secondary outcomes revealed that sugammadex could significantly shorten the time of TOF ≥ 0.9 compared to neostigmine (mean difference [MD] -4.52; 95%CI: -5.04 to -3.99; I2 = 80%; P < 0.01; Moderate quality). Furthermore, no significant differences were observed in the incidence of adverse events or hospital LOS.

CONCLUSIONS

This meta-analysis demonstrated that the use of sugammadex was associated with improved early perioperative neurocognitive function compared to neostigmine when used to reverse neuromuscular blockade, without an increase in the incidence of adverse events.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42024520287.

Impact of mild hypo- and hyperventilation on cerebral oxygen supply during general anesthesia

OBJECTIVE

Cerebral blood flow autoregulation is affected by several physiologic and medical factors. Especially arterial carbon dioxide pressures (PaCO2) impact cerebral blood flow. Only extensive changes in end-tidal CO2 have been studied so far. The aim of this study was to evaluate the impact of mild hypo- and hyperventilation on cerebral blood flow as assessed by regional cerebral red blood cell oxygen saturation (rSO2) in two age groups.

METHODS

Two groups of patients were compared under general anesthesia before the surgical procedure was started: A younger patient group (age < 40 years; YP) and older patients aged > 60 years (OP). Anesthetic management was standardized. In both groups, end-tidal CO2 was adjusted either to a low-normal value of 35-37 mmHg or a high-normal value of 43-45 mmHg for 15 min each. The sequence of these interventions was randomized. rSO2 was estimated by near-infrared spectroscopy (NIRS). The primary outcome was defined as the difference in rSO2 between hypo- and hyperventilation between the two age groups.

RESULTS

A total of 78 patients were included. In both groups, there was a statistically significant difference in rSO2 values after 15 min of hypo- versus hyperventilation. In the YP-group, rSO2 was 74 ± 4% after 15 min of hypoventilation and decreased to 68 ± 6% during hyperventilation (p < 0.001). In the OP-group, rSO2 was 71 ± 5% and 65 ± 6%, respectively (p < 0.001). There was no difference concerning changes in comparison of younger and elder patient groups (in both groups, Δ rSO2 = 6 ± 3%; p = 0.732).

CONCLUSION

Even mild hypoventilation increased rSO2 compared to mild hyperventilation and this difference occurred independent of age.

Intravenous injection of 0.5 μg/kg dexmedetomidine during plasma resection of tonsil adenoids can reduce the incidence of delirium and hemodynamics in children

OBJECTIVE

To investigate the effects of different doses of dexmedetomidine on delirium and hemodynamics after plasma resection of adenoids in children.

METHODS

A retrospective analysis was conducted on the clinical data of 80 children who underwent plasma adenoidectomy of tonsil at the Pediatric Hospital of Fudan University from January 2022 to December 2023. The patients were divided into normal saline group, 0.1 μg/kg dexmedetomidine group, and 0.5 μg/kg dexmedetomidine group according to the dose of dexmedetomidine injected intravenously. Hemodynamic changes, modified Yale Preoperative Anxiety Scale (mYPAS-SF) scores, pharyngeal pain (at rest and during swallowing), coagulation function, and postoperative adverse reactions were compared at T0, 10 min after dexmedetomidine pumping (T1), extubation (T2), recovery (T3), 2 h after returning to ward (T4), 12 h after returning to ward (T5) and 24 h after returning to ward (T6), respectively.

RESULTS

There were no significant differences in extubation time, recovery time, or unguardianship time among the three groups (P>0.05). The incidence of postoperative delirium was significantly lower in the 0.1 μg/kg dexmedetomidine group and 0.5 μg/kg dexmedetomidine group compared to the normal saline group (P<0.05), with the 0.5 μg/kg group showing better results. At T2, heart rate (HR) and mean arterial pressure (MAP) levels were significantly lower in 0.1 μg/kg group and 0.5 μg/kg dexmedetomidine group than those in normal saline group (P<0.05). The mYPAS-SF score was significantly lower in the 0.1 μg/kg group and 0.5 μg/kg dexmedetomidine groups than that of the normal saline group at T3, T4 and T5 (P<0.05). The score of pharyngeal pain during swallowing was significantly lower in the 0.5 μg/kg dexmedetomidine group at T5 than that of the normal saline group and 0.1 μg/kg dexmedetomidine group (P<0.05). Coagulation values (PT, APTT, and TT) were significantly altered 36 hours post-surgery, with PT, APTT, and TT increasing, while fibrinogen (FIB) decreased (P<0.05). Postoperative nasopharyngeal hemorrhage occurred in one case and nausea/vomiting in two cases in the saline group. No anesthesia-related adverse reactions were observed in the dexmedetomidine group.

CONCLUSION

Intravenous injection of 0.5 μg/kg dexmedetomidine during plasma resection of tonsillar adenoids can reduce the incidence of postoperative delirium, stabilize hemodynamics, relieve postoperative anxiety and pharyngeal pain, with minimal impacts on coagulation function. Additionally, it reduces the incidence of adverse reactions, making it a promising option for clinical use.

Preoperative hypoxic biomarkers and postoperative delirium in patients with obstructive sleep apnea

PURPOSE

Postoperative delirium (POD) in patients with obstructive sleep apnea (OSA) is associated with increased mortality and healthcare costs. In this study, we investigated the association of OSA risk, serum biomarkers for central nervous ischemia (S100B and NSE), and POD.

METHODS

After research ethics approval, patients completed the STOP BANG assessment before undergoing elective surgery. Blood was drawn for S100B and NSE measurement, and cognitive performance was tested using the Montreal Cognitive Assessment (MoCA) at study admission and postoperatively at discharge. Delirium assessment was performed using the Nursing Delirium Screening Scale (NuDESC) and the Confusion Assessment Method (CAM).

RESULTS

One hundred twenty-four enrolled patients were separated into three OSA-risk groups based on STOP BANG score testing (low risk, n = 22; intermediate risk, n = 67; high risk, n = 35). Preoperative NSE values increased with OSA risk (NSE in ng/ml; mean [range]; low risk: 15.6 [9.2-44.3]; intermediate risk: 21.8 [7.6-114.1]; high risk: 29.2 [10.1-151]; p = 0.039). Postoperative MoCA and NuDESC assessments were not different between the OSA-risk groups. We found a decreasing incidence for POD with increasing OSA risk (positive CAM: low risk: 18.1%, intermediate risk: 12.0%; high risk: 11.5%, p = 0.043). However, this was no longer detectable in a complete case analysis. In patients with POD, postoperative ischemic biomarker values were not different between OSA-risk groups.

CONCLUSION

We found a trend of decreasing POD incidence with increasing OSA risk, which was not robust in a complete case analysis. Our results possibly support the phenomenon of hypoxic preconditioning.

Real-World Evaluation of i-gel Introduction on Intraoperative Airway-Related Safety Events: A Retrospective Cohort Study From a New England Hospital Network

BACKGROUND

Several health care networks have fully adopted second-generation supraglottic airway (SGA) i-gel. Real-world evidence of enhanced patient safety after such practice change is lacking. We hypothesized that the implementation of i-gel compared to the previous LMA®-Unique™ would be associated with a lower risk of airway-related safety events.

METHODS

Adult patients undergoing general anesthesia with LMA-Unique or i-gel between January 2013 and June 2020 at an academic health care network were included. We assessed the influence of i-gel implementation on the trends of intraoperative airway-related safety events, a composite outcome of respiratory disturbances including intraoperative desaturation (<90%), hypo- or hypercapnia (<25 or >50 mm Hg), high driving pressures (>30 cmH2O), low tidal volumes (<4 mL/kg), multiple attempts of SGA placement, or emergency replacement with a tracheal tube, using adjusted ordinary least-squares regression interrupted time series analysis.

RESULTS

A total of 21,417 patients were included, and 5193 experienced airway-related safety events (24.2%). After the wider uptake of i-gel in January 2018, the reduction in the monthly trend of airway-related safety events was magnified to -0.3% per month (95% confidence interval [CI], -0.1% to -0.4%, P < .001), compared to the LMA-Unique period (-0.2% per month, 95% CI, -0.1% to -0.3%; P = .002).

CONCLUSIONS

We found a significant decline in the monthly trend of airway-related safety events after the full implementation of i-gel in our health care network. This study provides real-world patient safety and clinical effectiveness information to clinicians and decision-makers.

Clinical practice of one-lung ventilation in mainland China: a nationwide questionnaire survey

BACKGROUND

Limited information is available regarding the application of lung-protective ventilation strategies during one-lung ventilation (OLV) across mainland China. A nationwide questionnaire survey was conducted to investigate this issue in current clinical practice.

METHODS

The survey covered various aspects, including respondent demographics, the establishment and maintenance of OLV, intraoperative monitoring standards, and complications associated with OLV.

RESULTS

Five hundred forty-three valid responses were collected from all provinces in mainland China. Volume control ventilation mode, 4 to 6 mL per kilogram of predictive body weight, pure oxygen inspiration, and a low-level positive end-expiratory pressure ≤ 5 cm H2O were the most popular ventilation parameters. The most common thresholds of intraoperative respiration monitoring were peripheral oxygen saturation (SpO2) of 90-94%, end-tidal CO2 of 45 to 55 mm Hg, and an airway pressure of 30 to 34 cm H2O. Recruitment maneuvers were traditionally performed by 94% of the respondents. Intraoperative hypoxemia and laryngeal injury were experienced by 75% and 51% of the respondents, respectively. The proportions of anesthesiologists who frequently experienced hypoxemia during OLV were 19%, 24%, and 7% for lung, cardiovascular, and esophageal surgeries, respectively. Up to 32% of respondents were reluctant to perform lung-protective ventilation strategies during OLV. Multiple regression analysis revealed that the volume-control ventilation mode and an SpO2 intervention threshold of < 85% were independent risk factors for hypoxemia during OLV in lung and cardiovascular surgeries. In esophageal surgery, working in a tier 2 hospital and using traditional ventilation strategies were independent risk factors for hypoxemia during OLV. Subgroup analysis revealed no significant difference in intraoperative hypoxemia during OLV between respondents who performed lung-protective ventilation strategies and those who did not.

CONCLUSIONS

Lung-protective ventilation strategies during OLV have been widely accepted in mainland China and are strongly recommended for esophageal surgery, particularly in tier 2 hospitals. Implementing volume control ventilation mode and early management of oxygen desaturation might prevent hypoxemia during OLV.

Postoperative cognitive dysfunction in elderly postcardiac surgery patients: progress in rehabilitation application research

Postoperative cognitive dysfunction (POCD) is a prevalent complication of the central nervous system in elderly patients following cardiac surgery. This review aims to provide an overview of the etiology, risk factors, diagnostic assessment, and rehabilitation strategies for cognitive dysfunction occurring after cardiac surgery. The pathogenesis of POCD after cardiac surgery includes cerebral microembolism, neuroinflammation, and cryptogenic strokes. Risk factors are associated with advanced age, diminished preoperative cognitive status, and anesthesia. Cognitive function screening tools used for pre- and postoperative assessments can detect changes in patients' cognitive levels in a timely manner. The timely provision of appropriate rehabilitation methods, including cognitive function training, exercise training, transcranial direct current stimulation, and perioperative acupuncture, is crucial, with emerging technologies such as virtual reality playing an increasingly significant role. In conclusion, POCD is a common postoperative complication in elderly cardiac surgery patients, with age and reduced preoperative cognitive function being the primary risk factors. A comprehensive rehabilitation strategy can more effectively address postoperative cognitive dysfunction in patients.

Considerations for Anesthesia in Older Adults with Cannabis Use

Over the past decade, legislative changes occurred in the USA and the western world that were followed by a substantial increase in reported use of cannabis among the general population. Among patients undergoing anesthesia for surgery or interventional procedures, older patients-often defined as adults over 65 years-are one of the fastest-growing populations. Within this group, the prevalence of cannabis use almost tripled over the past decade. In addition to habitual cannabis use, recommendations for treatment of chronic pain with cannabinoids have become increasingly more common. The clinical relevance of cannabis use in older adults is supported by recent studies linking it to increased anesthetic requirements as well as respiratory, cardiovascular, and psychiatric complications following surgery. Still, evidence remains equivocal, as these associations may largely depend on the type, frequency, and route of cannabis administration, and current research is mostly limited to retrospective cohort studies. Multisystemic effects of cannabis can become especially relevant in patients of advanced age undergoing anesthesia, characterized by physiological and pharmacodynamic alterations as well as a higher risks of drug-to-drug interactions. Best-practice guidelines emphasize the need for detailed, systematic preoperative screening for habits of cannabis use, including the history, type, and frequency, to guide perioperative management in these patients. This review discusses considerations for anesthesia in older patients with habitual cannabis use while highlighting strategies and recommendations to ensure safe and effective anesthesia care.

Impact of Permissive Hypercapnia on Postoperative Early Plasma Neurofilament Light Chain in Elderly Patients Undergoing Laparoscopic Surgery: A Prospective, Randomized Controlled Trial

Background

The effects of intraoperative permissive hypercapnia (PaCO2 of 45-55 mmHg) on the central nervous system remain unclear. Neurofilament light chain (NfL, a protein found in the axons and nerve fibers of neurons) has been associated with central nervous system disorders. This study investigated the effect of intraoperative permissive hypercapnia on plasma NfL concentration 1 day postoperatively, and in turn on the central nervous system, during laparoscopic surgery.

Methods

This investigation was a prospective, single-blind randomized controlled trial. Eighty-four individuals aged above 60 years were randomly allocated to either the normocapnia group with an PaCO2 of 35-45 mmHg (n=42) or the hypercapnia group with a PaCO2 of 45-55 mmHg (n=42). The primary outcome was the 1-day postoperative plasma NfL concentration. Secondary outcomes included the area under the curve (AUC) values for PaCO2 and regional cerebral oxygen saturation (rSO2). The Mann-Whitney U-test was mainly used to analyze the outcomes.

Results

The final analysis included 38 and 40 patients in the normocapnia and hypercapnia groups, respectively. There was no statistically significant difference observed between the groups regarding the preoperative and 1-day postoperative plasma NfL concentration (14.0 [11.1, 19.9] vs 16.3 [9.06, 19.9] pg/mL, P>0.05; 23.4 [16.8, 32.3] vs 21.5 [15.6, 29.9] pg/mL, P>0.05, respectively). However, in both groups, the postoperative plasma concentration of NfL showed a significant increase when compared with the preoperative levels (both P < 0.001). The AUCs of PaCO2 and rSO2 from the beginning to the end of the pneumoperitoneum were significantly higher in the hypercapnia group compared with the normocapnia group (both P<0.05).

Conclusion

Our results indicate that intraoperative permissive hypercapnia targeting a PaCO2 of 45-55 mmHg does not significantly influence postoperative early plasma NfL elevation levels in elderly patients undergoing laparoscopic surgery. During general anesthesia, intraoperative permissive hypercapnia might not significantly impact the central nervous system.

Association between duration of phenoxybenzamine use and postoperative delirium in suspected adrenal pheochromocytoma: a retrospective cohort study

Background

At present, the available evidence regarding the relationship between duration of phenoxybenzamine use and postoperative delirium is inadequate in suspected adrenal pheochromocytoma.

Objective

To understand how changes in the duration of phenoxybenzamine use may affect postoperative delirium. The secondary objective of this study is to explore how the duration of phenoxybenzamine use may jointly influence postoperative delirium together with other interacting variables.

Methods

We conducted a retrospective cohort study involving 527 participants with a preoperative diagnosis of suspected pheochromocytoma. CT characteristics, preoperative preparation, intraoperative infusion, estimated bleeding, use of intraoperative vasoactive drugs, and outcomes were obtained from all participants. Logistic regression and interaction effects were utilized to substantiate the research objectives.

Results

A total of 108 (20.5%) developed postoperative delirium, which was seen in 37 (18.0%) in the pheochromocytoma group and 71 (22.0%) in the non-pheochromocytoma group. The incidence of postoperative delirium showed no statistically significant differences in the two groups. A positive association between the duration of phenoxybenzamine use and the risk of postoperative delirium was observed (OR = 1.05, 95%CI = 1.03-1.08, p < 0.01), independent of confounders. The relationship between the duration of phenoxybenzamine use and postoperative delirium differed according to the presence or absence of pheochromocytoma, suggesting an interactive effect (p < 0.05).

Conclusion

This study highlights the influence of inappropriate duration of phenoxybenzamine use on the risk of incident postoperative delirium, independent of confounders. The effect of duration of phenoxybenzamine use causes a further increase in the risk of postoperative delirium, especially in non-pheochromocytomas.

Previous Coronavirus Disease-2019 Infection and Lung Mechanics in Surgical Patients: A Hospital Registry Study

BACKGROUND

Long-term pulmonary complications have been reported after a coronavirus disease-2019 (COVID-19). We hypothesized that a history of COVID-19 is associated with a measurable decrease in baseline respiratory system compliance in patients undergoing general anesthesia.

METHODS

In this hospital registry study, we included adult patients undergoing general anesthesia between January 2020 and March 2022 at a tertiary health care network in Massachusetts. We excluded patients with an American Society of Anesthesiologists physical status >IV, laryngoscopic surgeries, and patients who arrived intubated. The primary exposure was a history of COVID-19. The primary outcome was baseline respiratory system compliance (mL/cmH 2 O). Effects of severity of infection, surges (Alpha 1 , Alpha 2 , Delta, and Omicron), patient demographics, and time between infection and assessment of compliance were investigated.

RESULTS

A total of 19,921 patients were included. Approximately 1386 (7.0%) patients had a history of COVID-19. A history of COVID-19 at any time before surgery was associated with a measurably lower baseline respiratory system compliance (ratio of means adj = 0.96; 95% confidence interval [CI], 0.94-0.97; P < .001; adjusted compliance difference: -1.6 mL/cmH 2 O). The association was more pronounced in patients with a severe form of COVID-19 (ratio of means adj = 0.95; 95% CI, 0.90-0.99; P = .02, adjusted compliance difference: -2 mL/cmH 2 O). Alpha 1 , Alpha 2 , and Delta surges, but not Omicron, led to a lower baseline respiratory system compliance ( P < .001, P = .02, and P < .001). The Delta surge effect was magnified in Hispanic ethnicity ( P -for-interaction = 0.003; ratio of means adj = 0.83; 95% CI, 0.74-0.93; P = .001; adjusted compliance difference: -4.6 mL/cmH 2 O).

CONCLUSIONS

A history of COVID-19 infection during Alpha 1 , Alpha 2 , and Delta surges was associated with a measurably lower baseline respiratory system compliance.

Association of anaesthesia provider sex with perioperative complications: a two-centre retrospective cohort study

BACKGROUND

Previous studies suggested that surgeon sex is associated with differential patient outcomes. Whether this also applies to anaesthesia providers is unclear. We hypothesised that female sex of the primary anaesthesia provider is associated with lower risk of perioperative complications.

METHODS

The first case for all adult patients undergoing anaesthesia care between 2008 and 2022 at two academic healthcare networks in the USA was included in this retrospective cohort study. The primary exposure was the sex of the anaesthesia provider who spent the most time in the operating theatre during the case. The primary outcome was intraoperative complications, defined as hypotension (mean arterial blood pressure <55 mm Hg for ≥5 cumulative minutes) or hypoxaemia (oxygen saturation <90% for >2 consecutive minutes). The co-primary outcome was 30-day adverse postoperative events (including complications, readmission, and mortality). Analyses were adjusted for a priori defined confounders.

RESULTS

Among 364,429 included patients, 57,550 (15.8%) experienced intraoperative complications and 55,168 (15.1%) experienced adverse postoperative events. Care by female compared with male anaesthesia providers was associated with lower risk of intraoperative complications (adjusted odds ratio [aOR] 0.95, 95% confidence interval [CI] 0.94-0.97, P<0.001), which was magnified among non-trainees (aOR 0.84, 95% CI 0.82-0.87, P-for-interaction<0.001). Anaesthesia provider sex was not associated with the composite of adverse postoperative events (aOR 1.00, 95% CI 0.98-1.02, P=0.88).

CONCLUSIONS

Care by a female anaesthesia provider was associated with a lower risk of intraoperative complications, which was magnified among non-trainees. Future studies should investigate underlying mechanisms.

Effect of phenylephrine versus ephedrine on the incidence of postoperative delirium in olderly adults undergoing knee arthroplasty under general anesthesia: a single-center trial

In addition to stabilizing blood pressure (BP), ephedrine and phenylephrine have distinct effects on regional cerebral oxygen saturation (rSO2). However, whether its effect on rSO2 affects the occurrence of postoperative delirium (POD) remains unclear. Therefore, the aim of this study is to compare the effects of ephedrine and phenylephrine for BP maintenance on the incidence of POD in olderly adults who underwent knee arthroplasty under general anesthesia. One hundred twenty patients who were between 60 and 90 years old and underwent knee arthroplasty were included in this study. The patients were randomly divided into two groups: the ephedrine group and the phenylephrine group. After anesthesia induction, ephedrine and phenylephrine were continuously infused to maintain the intraoperative mean arterial pressure within the normal range (baseline mean arterial pressure ± 20%). The primary outcome measures included the incidence of POD within 1-3 days after surgery. The incidence of POD on the first day after surgery was lower in the ephedrine group than in the phenylephrine group (33% vs. 7%, P < 0.001). However, there was no significant difference in the incidence of POD between the two groups on the second and third postoperative days. Compared with the phenylephrine group, the ephedrine group experienced significantly greater cardiac output (CO) and rSO2 (P < 0.05).Clinical Trials Registry: ChiCTR2200064849, principal investigator: Changjian Zheng.

Trace of delirium after robotic lower abdominal tumor resection at different end-tidal carbon dioxide: a RCT trial

BACKGROUND

Postoperative delirium (POD) often occurs in oncology patients, further increasing the medical and financial burden. Robotic technology in lower abdominal tumors resection reduces surgical trauma but increases risks such as carbon dioxide (CO2) absorption. This study aimed to investigate the differences in their occurrence of POD at different end-tidal CO2 levels.

METHOD

This study was approved by the Ethics Committee of Affiliated Hospital of He Bei University (HDFY-LL-2022-169). The study was registered with the Chinese Clinical Trials Registry on URL: http://www.chictr.org.cn , Registry Number: ChiCTR2200056019 (Registry Date: 27/08/2022). In patients scheduled robotic lower abdominal tumor resection from September 1, 2022 to December 31, 2022, a comprehensive delirium assessment was performed three days postoperatively using the CAM scale with clinical review records. Intraoperative administration of different etCO2 was performed depending on the randomized grouping after intubation. Group L received lower level etCO2 management (31-40mmHg), and Group H maintained the higher level(41-50mmHg) during pneumoperitoneum. Data were analyzed using Pearson Chi-Square or Wilcoxon Rank Sum tests and multiple logistic regression. Preoperative mental status score, alcohol impairment score, nicotine dependence score, history of hypertension and diabetes, duration of surgery and worst pain score were included in the regression model along with basic patient information for covariate correction analysis.

RESULTS

Among the 103 enrolled patients, 19 (18.4%) developed postoperative delirium. The incidence of delirium in different etCO2 groups was 21.6% in Group L and 15.4% in Group H, respectively, with no statistical differences. In adjusted multivariate analysis, age and during of surgery were statistically significant predictors of postoperative delirium. The breath-hold test was significantly lower postoperatively, but no statistical differences were found between two groups.

CONCLUSION

With robotic assistant, the incidence of postoperative delirium in patients undergoing lower abdominal tumor resection was not modified by different end-tidal carbon dioxide management, however, age and duration of surgery were positively associated risk factors.

Effect of near-infrared spectroscopy on postoperative delirium in cardiac surgery with cardiopulmonary bypass: a systematic review and meta-analysis

Background

Postoperative delirium (POD) is a common anesthetic side effect in cardiac surgery. However, the role of oxygen saturation monitoring in reducing postoperative delirium has been controversial. Therefore, this meta-analysis aimed to analyze whether NIRS monitoring during cardiac surgery under cardiopulmonary bypass could reduce the incidence of postoperative delirium.

Methods

PubMed, Web of Science, Cochrane Library, Embase and China National Knowledge Infrastructure (CNKI) databases were systematically searched using the related keywords for randomized-controlled trials (RCTs) published from their inception to March 16, 2024. This review was conducted by the Preferred Reporting Project and Meta-Analysis Statement (PRISMA) guidelines for systematic review. The primary outcome was postoperative delirium, and the second outcomes included the length of ICU stay, the incidence of kidney-related adverse outcomes, and the incidence of cardiac-related adverse outcomes.

Results

The incidence of postoperative delirium could be reduced under the guidance of near-infrared spectroscopy monitoring (OR, 0.657; 95% CI, 0.447-0.965; P = 0.032; I2 = 0%). However, there were no significant differences in the length of ICU stay (SMD, 0.005 days; 95% CI, -0.135-0.146; P = 0.940; I2 = 39.3%), the incidence of kidney-related adverse outcomes (OR, 0.761; 95% CI, 0.386-1.500; P = 0.430; I2 = 0%), and the incidence of the cardiac-related adverse outcomes (OR, 1.165; 95% CI, 0.556-2.442; P = 0.686; I2 = 0%) between the two groups.

Conclusion

Near-infrared spectroscopy monitoring in cardiac surgery with cardiopulmonary bypass helps reduce postoperative delirium in patients.

Systematic Review Registration

PROSPERO, identifier, CRD42023482675.

Recovery and safety with prolonged high-frequency jet ventilation for catheter ablation of atrial fibrillation: A hospital registry study from a New England healthcare network

STUDY OBJECTIVE

To investigate post-procedural recovery as well as peri-procedural respiratory and hemodynamic safety parameters with prolonged use of high-frequency jet ventilation (HFJV) versus conventional ventilation in patients undergoing catheter ablation for atrial fibrillation.

DESIGN

Hospital registry study.

SETTING

Tertiary academic teaching hospital in New England.

PATIENTS

1822 patients aged 18 years and older undergoing catheter ablation between January 2013 and June 2020.

INTERVENTIONS

HFJV versus conventional mechanical ventilation.

MEASUREMENTS

The primary outcome was post-anesthesia care unit (PACU) length of stay. In secondary analyses we assessed the effect of HFJV on intra-procedural hypoxemia, defined as the occurrence of peripheral hemoglobin oxygen saturation (SpO2) <90%, post-procedural respiratory complications (PRC) as well as intra-procedural hypocarbia and hypotension. Multivariable negative binomial and logistic regression analyses, adjusted for patient and procedural characteristics, were applied.

MAIN RESULTS

1157 patients (63%) received HFJV for a median (interquartile range [IQR]) duration of 307 (253-360) minutes. The median (IQR) length of stay in the PACU was 244 (172-370) minutes in patients who underwent ablation with conventional mechanical ventilation and 226 (163-361) minutes in patients receiving HFJV. In adjusted analyses, patients undergoing HFJV had a longer PACU length of stay (adjusted absolute difference: 37.7 min; 95% confidence interval [CI] 9.7-65.8; p = 0.008). There was a higher risk of intra-procedural hypocarbia (adjusted odds ratio [ORadj] 5.90; 95%CI 2.63-13.23; p < 0.001) and hypotension (ORadj 1.88; 95%CI 1.31-2.72; p = 0.001) in patients undergoing HFJV. No association was found between the use of HFJV and intra-procedural hypoxemia or PRC (p = 0.51, and p = 0.97, respectively).

CONCLUSION

After confounder adjustment, HFJV for catheter ablation procedures for treatment of atrial fibrillation was associated with a longer length of stay in the PACU. It was further associated with an increased risk of intra-procedural abnormalities including abnormal carbon dioxide homeostasis, as well as intra-procedural arterial hypotension.

Association of ketamine use during procedural sedation with oxygen desaturation and healthcare utilisation: a multicentre retrospective hospital registry study

BACKGROUND

We investigated the effects of ketamine on desaturation and the risk of nursing home discharge in patients undergoing procedural sedation by anaesthetists.

METHODS

We included adult patients who underwent procedures under monitored anaesthetic care between 2005 and 2021 at two academic healthcare networks in the USA. The primary outcome was intraprocedural oxygen desaturation, defined as oxygen saturation <90% for ≥2 consecutive minutes. The co-primary outcome was a nursing home discharge.

RESULTS

Among 234,170 included patients undergoing procedural sedation, intraprocedural desaturation occurred in 5.6% of patients who received ketamine vs 5.2% of patients who did not receive ketamine (adjusted odds ratio [ORadj] 1.22, 95% confidence interval [CI] 1.15-1.29, P<0.001; adjusted absolute risk difference [ARDadj] 1%, 95% CI 0.7-1.3%, P<0.001). The effect was magnified by age >65 yr, smoking, or preprocedural ICU admission (P-for-interaction <0.001, ORadj 1.35, 95% CI 1.25-1.45, P<0.001; ARDadj 2%, 95% CI 1.56-2.49%, P<0.001), procedural risk factors (upper endoscopy of longer than 2 h; P-for-interaction <0.001, ORadj 2.91, 95% CI 1.85-4.58, P<0.001; ARDadj 16.2%, 95% CI 9.8-22.5%, P<0.001), and high ketamine dose (P-for-trend <0.001, ORadj 1.61, 95% CI, 1.43-1.81 for ketamine >0.5 mg kg-1). Concomitant opioid administration mitigated the risk (P-for-interaction <0.001). Ketamine was associated with higher odds of nursing home discharge (ORadj 1.11, 95% CI 1.02-1.21, P=0.012; ARDadj 0.25%, 95% CI 0.05-0.46%, P=0.014).

CONCLUSIONS

Ketamine use for procedural sedation was associated with an increased risk of oxygen desaturation and discharge to a nursing home. The effect was dose-dependent and magnified in subgroups of vulnerable patients.

Intraoperative Use of Phenylephrine versus Ephedrine and Postoperative Delirium: A Multicenter Retrospective Cohort Study

BACKGROUND

The treatment of intraoperative hypotension with phenylephrine may impair cerebral perfusion through vasoconstriction, which has been linked to postoperative delirium. The hypothesis was that intraoperative administration of phenylephrine, compared to ephedrine, is associated with higher odds of postoperative delirium.

METHODS

A total of 103,094 hospitalized adults undergoing general anesthesia for noncardiac, non-neurosurgical procedures between 2008 and 2020 at two tertiary academic healthcare networks in Massachusetts were included in this multicenter hospital registry study. The primary exposure was the administration of phenylephrine versus ephedrine during surgery, and the primary outcome was postoperative delirium within 7 days. Multivariable logistic regression analyses adjusted for a priori defined confounding variables including patient demographics, comorbidities, and procedural factors including magnitude of intraoperative hypotension were applied.

RESULTS

Between the two healthcare networks, 78,982 (76.6%) patients received phenylephrine, and 24,112 (23.4%) patients received ephedrine during surgery; 770 patients (0.8%) developed delirium within 7 days. The median (interquartile range) total intraoperative dose of phenylephrine was 1.0 (0.2 to 3.3) mg and 10.0 (10.0 to 20.0) mg for ephedrine. In adjusted analyses, the administration of phenylephrine, compared to ephedrine, was associated with higher odds of developing postoperative delirium within 7 days (adjusted odds ratio, 1.35; 95% CI, 1.06 to 1.71; and adjusted absolute risk difference, 0.2%; 95% CI, 0.1 to 0.3%; P = 0.015). A keyword and manual chart review-based approach in a subset of 45,465 patients further validated these findings (delirium incidence, 3.2%; adjusted odds ratio, 1.88; 95% CI, 1.49 to 2.37; P < 0.001). Fractional polynomial regression analysis further indicated a dose-dependent effect of phenylephrine (adjusted coefficient, 0.08; 95% CI, 0.02 to 0.14; P = 0.013, per each μg/kg increase in the cumulative phenylephrine dose).

CONCLUSIONS

The administration of phenylephrine compared to ephedrine during general anesthesia was associated with higher odds of developing postoperative delirium. Based on these data, clinical trials are warranted to determine whether favoring ephedrine over phenylephrine for treatment of intraoperative hypotension can reduce delirium after surgery.

EDITOR’S PERSPECTIVE

Differences in the Incidence of Hypotension and Hypertension between Sexes during Non-Cardiac Surgery: A Systematic Review and Meta-Analysis

Background: Major determinants of blood pressure (BP) include sex and age. In youth, females have lower BP than males, yet in advanced age, more pronounced BP increases result in higher average BPs in females over 65. This hypothesis-generating study explored whether age-related BP divergence impacts the incidence of sex-specific intraoperative hypotension (IOH) or hypertension. Methods: We systematically searched PubMed and Embase databases for studies reporting intraoperative BP in males and females in non-cardiac surgery. We analyzed between-sex differences in the incidence of IOH and intraoperative hypertension (primary endpoint). Results: Among 793 identified studies, 14 were included in this meta-analysis, comprising 1,110,636 patients (56% female). While sex was not associated with IOH overall (females: OR 1.10, 95%CI [0.98-1.23], I2 = 99%), a subset of studies with an average age ≥65 years showed increased exposure to IOH in females (OR 1.17, 95%CI [1.01-1.35], I2 = 94%). One study reported sex-specific differences in intraoperative hypertension, with a higher incidence in females (31% vs. 28%). Conclusions: While sex-specific reporting on intraoperative BP was limited, IOH did not differ between sexes. However, an exploratory subgroup analysis offers the hypothesis that females of advanced age may face an increased risk of IOH, warranting further investigation.

High Mechanical Power and Driving Pressures are Associated With Postoperative Respiratory Failure Independent From Patients' Respiratory System Mechanics

OBJECTIVES

High mechanical power and driving pressure (ΔP) have been associated with postoperative respiratory failure (PRF) and may be important parameters guiding mechanical ventilation. However, it remains unclear whether high mechanical power and ΔP merely reflect patients with poor respiratory system mechanics at risk of PRF. We investigated the effect of mechanical power and ΔP on PRF in cohorts after exact matching by patients' baseline respiratory system compliance.

DESIGN

Hospital registry study.

SETTING

Academic hospital in New England.

PATIENTS

Adult patients undergoing general anesthesia between 2008 and 2020.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary exposure was high (≥ 6.7 J/min, cohort median) versus low mechanical power and the key-secondary exposure was high (≥ 15.0 cm H 2 O) versus low ΔP. The primary endpoint was PRF (reintubation or unplanned noninvasive ventilation within seven days). Among 97,555 included patients, 4,030 (4.1%) developed PRF. In adjusted analyses, high intraoperative mechanical power and ΔP were associated with higher odds of PRF (adjusted odds ratio [aOR] 1.37 [95% CI, 1.25-1.50]; p < 0.001 and aOR 1.45 [95% CI, 1.31-1.60]; p < 0.001, respectively). There was large variability in applied ventilatory parameters, dependent on the anesthesia provider. This facilitated matching of 63,612 (mechanical power cohort) and 53,260 (ΔP cohort) patients, yielding identical baseline standardized respiratory system compliance (standardized difference [SDiff] = 0.00) with distinctly different mechanical power (9.4 [2.4] vs 4.9 [1.3] J/min; SDiff = -2.33) and ΔP (19.3 [4.1] vs 11.9 [2.1] cm H 2 O; SDiff = -2.27). After matching, high mechanical power and ΔP remained associated with higher risk of PRF (aOR 1.30 [95% CI, 1.17-1.45]; p < 0.001 and aOR 1.28 [95% CI, 1.12-1.46]; p < 0.001, respectively).

CONCLUSIONS

High mechanical power and ΔP are associated with PRF independent of patient's baseline respiratory system compliance. Our findings support utilization of these parameters for titrating mechanical ventilation in the operating room and ICU.

[Non-pharmacological Management of Postoperative Delirium]

Postoperative delirium is common especially in the elderly and is associated with high rates of morbidity and mortality. Non-pharmacological multicomponent interventions are effective in reducing the incidence and to a degree the duration of postoperative delirium and are recommended in international guidelines on postoperative delirium as first line intervention for management of delirium. Non-pharmacological management of postoperative delirium consists of strategies for risk stratification, risk reduction by non-pharmacological bundle interventions, early recognition of delirium by screening protocols and immediate therapy of underlying causes of delirium and continuation of non-pharmacological bundles. Non-pharmacological bundle interventions address common perioperative risk factors. Bundles comprise strategies for oxygenation, mobilization, hydration and nutrition, sensory and cognitive stimulation, reorientation, modifications of environmental factors such as design aspects and noise reduction, adequate analgesia, management of agitation and anxiety, protecting circadian rhythms for example by adequate light exposure during daytime, family involvement and timely reduction of unnecessary catheters and anticholinergic drugs. The article aims at providing an overview of non-pharmacological management of postoperative delirium in the hospital.