Intraoperative oxygen concentration and neurocognition after cardiac surgery: study protocol for a randomized controlled trial

Effect of postoperative oxygen therapy regimen modification on oxygenation in patients with acute type A aortic dissection

Objective

In this study, we investigated the effect of various oxygen therapy regimens on oxygenation in patients with acute type A aortic dissection (AAD).

Methods

A quasi-randomized controlled trial was conducted, in which patients with AAD hospitalized for surgery from June to September 2021 were assigned to the control group (patients received conventional oxygen therapy after postoperative mechanical ventilation, weaning, and extubation) and those who were admitted from October to December 2021 were assigned to the observation group [patients underwent optimally adjusted therapy based on the treatment of the control group, which mainly included prioritized elevation of positive end-expiratory pressure (PEEP) and restricted use of the fraction of inspired oxygen (FiO2)].The postoperative oxygenation index, blood gas analysis, and duration of mechanical ventilation were compared between the two groups.

Results

There were significant differences in oxygenation observed at 2 h postoperatively between the groups. 12, 24, and 72 h postoperatively, the oxygenation index varied significantly between the two groups. There were statistically significant differences in the time effects of the oxygenation index and PaO2 between the two groups, as well as significant differences in the length of stay in the intensive care unit.

Conclusion

For the postoperative care of patients with AAD, it is suggested that the minimum FiO2 required for oxygenation of patients be maintained. In addition, it is possible to enhance PEEP as a priority when PaO2 is low.

Intraoperative hyperoxygenation may negatively affect postoperative cognitive functions in coronary artery bypass graft operations: A randomized controlled study

OBJECTIVE

In this study, it was aimed to compare various parameters during surgery and postoperative cognitive functions in patients undergoing coronary artery bypass graft (CABG) surgery using different levels of perioperative oxygen.

METHODS

One hundred patients scheduled for elective CABG surgery were included in the study. The patients were divided into two groups according to arterial oxygen levels during surgery. In the normoxia group (NG) (n = 50), partial arterial oxygen pressure (PaO₂ ) was between ≥100 and <180 mmHg with at least 40% fraction of inspired oxygen (FiO₂ ) mechanical ventilation (MV), and in the hyperoxia group (HG) (n = 50), PaO₂ was ≥180 mmHg with 100% FiO₂ MV. Hemodynamic parameters, peripheral oxygen saturation (SpO₂ ), regional cerebral oxygen saturation (rSO₂ ) measured from bilateral sensors, and blood gas values were recorded at the planned measurement times. Postoperative features (mortality and infection rates, length of stay in the hospital, and intensive care unit) and complications of the patients have been recorded (low cardiac output syndrome, renal failure, delirium). Mini-Mental State Examination (MMSE) test was applied to the patients before and at the 12th, 24th hours; on the first, third, sixth months after surgery.

RESULTS

Extubation time was found to be shorter in NG (p < .05). Between the groups, rSO₂ and mean arterial pressure were found to be significantly lower in HG at the time of T4 measurement (p = .042, p = .038, respectively). MMSE values of the groups at the first, third, and sixth months were found to be significantly higher in NG (p = .017, p = .014, p = .002, respectively).

CONCLUSION

Hyperoxemia application during CABG may be associated with worse postoperative late-term cognitive functions.

Early Outcomes of a High PaO2/FiO2 Ratio during Cardiopulmonary Bypass

Background: In cardiac surgery, supraphysiological oxygen levels are frequently applied perioperatively. In this study, we examined the postoperative effect of perioperative hyperoxemia in cardiac surgery. Methods: All patients who underwent mitral valve replacement via the standard sternotomy method between 2010 and 2021 were analyzed by scanning the hospital data system. The patients were divided into 2 groups: the hyperoxemic group (partial pressure of oxygen/fraction of inspired oxygen [PaO₂/FiO₂] > 500 mmHg) (Group I) and the normoxemic group (300 mmHg < PaO₂/FiO₂ < 500 mmHg) (Group II) according to the mean of 3 PaO₂/FiO₂ values calculated by using 3 PaO₂ and 3 FiO₂ levels. Postoperative complications, the mechanical ventilation time, the need for noninvasive mechanical ventilator support, the length of intensive care unit (ICU) stay, the hospitalization period, and the mortality rate of the groups were compared. Results: A total of 78 patients were included in the study, and 53 of the patients (67.9%) were female. The mean age of the patients was 58.89±12.60 years. The total mechanical ventilation time was significantly higher in the hyperoxemic group than in Group II (P<0.001) (18.18±12.90 h and 11.45±7.85 h, respectively). The amount of postoperative bleeding was significantly higher in Group I (P=0.003) (539.47±201.74 mL and 417.50±186.93 mL, respectively). The total amount of blood products administered during surgery and ICU stay was higher in Group I (P=0.041) (3.55±1.59 units and 2.87±1.89 units, respectively). Conclusion: We observed that the group with hyperoxemia during cardiopulmonary bypass had a higher amount of postoperative bleeding and the need for transfusion, as well as a longer duration of mechanical ventilation and intensive care.

Delirium in Older Adults: What a Surgeon Needs to Know

Delirium remains a challenging clinical problem in hospitalized older adults, especially for postoperative patients. This complication, with a high risk of postoperative mortality and an increased length of stay, frequently occurs in older adult patients. This brief narrative paper aims to review the recent literature regarding delirium and its most recent update. We also offer physicians a brief and essential clinical practice guide to managing this acute and common disease.

Incidence and predictors of delirium on the intensive care unit after acute myocardial infarction, insight from a retrospective registry

OBJECTIVES

This study aimed to identify the incidence and potential risk factors for delirium after myocardial infarction (MI).

BACKGROUND

Delirium is a common complication on intensive care units. Data on incidence and especially on predictors of delirium in patients after acute MI are rare.

METHODS

In this retrospective study, all patients hospitalized for MI treated with coronary angiography in an university hospital in 2018 were included and analyzed. Onset of delirium within the first 5 days after MI was attributed to the MI and was defined by a Nursing Delirium screening scale (NuDesc) ≥2. This score is taken as part of daily care in every patient on intensive care unit three times a day by especially trained nurses.

RESULTS

A total of 624 patients with MI (age 68.5 ± 13.2 years, ST-elevation MI 41.6%, hospital mortality 3.2%) were included in the study. Delirium was detected in 10.9% of all patients. In the subgroup of patients with a stay on the intensive care unit (ICU) for more than 24 hr (n = 229), delirium was detected in 29.7%. Hospital and ICU stay were significantly longer in patients with delirium (p < .001). Delirium was an independent predictor of prolonged ICU-stay. Independent predictors of delirium were age, dementia, alcohol abuse, cardiac arrest, hypotension, and leucocytosis. Infarct size or presentation with ST-elevation were not associated with incidence of delirium.

CONCLUSION

Development of delirium is frequent after acute MI and prolongs hospitalization. Incidence of delirium is associated with clinical instability, preexisting comorbidity, and age rather than MI type or size.

Intraoperative Oxygen Concentration and Neurocognition after Cardiac Surgery

BACKGROUND

Despite evidence suggesting detrimental effects of perioperative hyperoxia, hyperoxygenation remains commonplace in cardiac surgery. Hyperoxygenation may increase oxidative damage and neuronal injury leading to potential differences in postoperative neurocognition. Therefore, this study tested the primary hypothesis that intraoperative normoxia, as compared to hyperoxia, reduces postoperative cognitive dysfunction in older patients having cardiac surgery.

METHODS

A randomized double-blind trial was conducted in patients aged 65 yr or older having coronary artery bypass graft surgery with cardiopulmonary bypass. A total of 100 patients were randomized to one of two intraoperative oxygen delivery strategies. Normoxic patients (n = 50) received a minimum fraction of inspired oxygen of 0.35 to maintain a Pao2 above 70 mmHg before and after cardiopulmonary bypass and between 100 and 150 mmHg during cardiopulmonary bypass. Hyperoxic patients (n = 50) received a fraction of inspired oxygen of 1.0 throughout surgery, irrespective of Pao2 levels. The primary outcome was neurocognitive function measured on postoperative day 2 using the Telephonic Montreal Cognitive Assessment. Secondary outcomes included neurocognitive function at 1, 3, and 6 months, as well as postoperative delirium, mortality, and durations of mechanical ventilation, intensive care unit stay, and hospital stay.

RESULTS

The median age was 71 yr (interquartile range, 68 to 75), and the median baseline neurocognitive score was 17 (16 to 19). The median intraoperative Pao2 was 309 (285 to 352) mmHg in the hyperoxia group and 153 (133 to 168) mmHg in the normoxia group (P < 0.001). The median Telephonic Montreal Cognitive Assessment score on postoperative day 2 was 18 (16 to 20) in the hyperoxia group and 18 (14 to 20) in the normoxia group (P = 0.42). Neurocognitive function at 1, 3, and 6 months, as well as secondary outcomes, were not statistically different between groups.

CONCLUSIONS

In this randomized controlled trial, intraoperative normoxia did not reduce postoperative cognitive dysfunction when compared to intraoperative hyperoxia in older patients having cardiac surgery. Although the optimal intraoperative oxygenation strategy remains uncertain, the results indicate that intraoperative hyperoxia does not worsen postoperative cognition after cardiac surgery.

EDITOR’S PERSPECTIVE

Effect of combined intravenous-inhalation anesthesia on postoperative cognitive dysfunction after laparoscopic radical resection of cervical cancer: A protocol for systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of combined intravenous-inhalation anesthesia (CIVIA) on postoperative cognitive dysfunction (POCD) after laparoscopic radical resection of cervical cancer.

METHODS

By using a predefined standardized study protocol, we conducted a systematic review of randomized controlled trials (RCTs) with meta-analysis, searching the following data bases: PubMed, Embase, Web of Science, and Cochrane Library.

RESULTS

This systematic review evaluated the effect of CIVIA on POCD after laparoscopic radical resection of cervical cancer.

CONCLUSION

This systematic review provided up-to-date evidence to evaluate the effect of CIVIA on POCD after laparoscopic radical resection of cervical cancer.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/82FNA.

LncRNA-MYL2-2 and miR-124-3p Are Associated with Perioperative Neurocognitive Disorders in Patients after Cardiac Surgery

BACKGROUND

Perioperative neurocognitive disorders (PND) resulting from cardiac surgery is a complication with high morbidity and mortality. However, the pathogenesis is unknown.

METHODS

For the sake of investigating the risk factors and mechanism of PND, we collected the characteristics and neurological scores of patients undergoing cardiac surgery in the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University and Affiliated Hospital of Southwest Medical University from Jan 1, 2016 to Dec 11, 2018.

RESULTS

We found that age and left atrial thrombus are independent risk factors for PND after cardiac surgery. Furthermore, the serum of 29 patients was collected on the 7th day after cardiac surgery for detecting the expression of lncRNA-MYL2-2 and miR-124-3p. Increased lncRNA-MYL2-2 and decreased miR-124-3p in serum were associated with the decline of patients' cognition.

CONCLUSIONS

LncRNA-MYL2-2 and miRNA-124-3p may jointly participate in the occurrence and development of PND after cardiac surgery. These important findings are advantaged to further understand the pathogenesis of PND and prevent it, provide new biomarkers for the diagnosis and monitoring of PND.

Prevention of Early Postoperative Decline: A Randomized, Controlled Feasibility Trial of Perioperative Cognitive Training

BACKGROUND

Postoperative delirium and postoperative cognitive dysfunction (POCD) are common after cardiac surgery and contribute to an increased risk of postoperative complications, longer length of stay, and increased hospital mortality. Cognitive training (CT) may be able to durably improve cognitive reserve in areas deficient in delirium and POCD and, therefore, may potentially reduce the risk of these conditions. We sought to determine the feasibility and potential efficacy of a perioperative CT program to reduce the incidence of postoperative delirium and POCD in older cardiac surgery patients.

METHODS

Randomized controlled trial at a single tertiary care center. Participants included 45 older adults age 60-90 undergoing cardiac surgery at least 10 days from enrollment. Participants were randomly assigned in a 1:1 fashion to either perioperative CT via a mobile device or a usual care control. The primary outcome of feasibility was evaluated by enrollment patterns and adherence to protocol. Secondary outcomes of postoperative delirium and POCD were assessed using the Confusion Assessment Method and the Montreal Cognitive Assessment, respectively. Patient satisfaction was assessed via a postoperative survey.

RESULTS

Sixty-five percent of eligible patients were enrolled. Median (interquartile range [IQR]) adherence (as a percentage of prescribed minutes played) was 39% (20%-68%), 6% (0%-37%), and 19% (0%-56%) for the preoperative, immediate postoperative, and postdischarge periods, respectively. Median (IQR) training times were 245 (136-536), 18 (0-40), and 122 (0-281) minutes for each period, respectively. The incidence of postoperative delirium (CT group 5/20 [25%] versus control 3/20 [15%]; P = .69) and POCD (CT group 53% versus control 37%; P = .33) was not significantly different between groups for either outcome in this limited sample. CT participants reported a high level of agreement (on a scale of 0-100) with statements that the program was easy to use (median [IQR], 87 [75-97]) and enjoyable (85 [79-91]). CT participants agreed significantly more than controls that their memory (median [IQR], 75 [54-82] vs 51 [49-54]; P = .01) and thinking ability (median [IQR], 78 [64-83] vs 50 [41-68]; P = .01) improved as a result of their participation in the study.

CONCLUSIONS

A CT program designed for use in the preoperative period is an attractive target for future investigations of cognitive prehabilitation in older cardiac surgery patients. Changes in the functionality of the program and enrichment techniques may improve adherence in future trials. Further investigation is necessary to determine the potential efficacy of cognitive prehabilitation to reduce the risk of postoperative delirium and POCD.

Current Perspectives on Postoperative Cognitive Dysfunction in the Ageing Population

Postoperative cognitive dysfunction (POCD) is defined as a prolonged cognitive function impairment that occurs within weeks to months of a surgical procedure. It is especially prevalent in the elderly population, leading to increased morbidity and mortality. As anaesthetic and surgical care continues to improve and become increasingly safer, a significantly greater number of older patients have elective surgical procedures today, yet this comes with an increased POCD risk as they go through the perioperative phases. Although the pathophysiology behind the development of POCD is still under investigation, current causative mechanisms include the mode of anaesthesia administered, anaesthetic used, cerebral hypoperfusion, hyperventilation and neuroinflammation. These findings lend an insight into the importance of being cognisant of the higher likelihood of POCD in at-risk patients, including the elderly, and taking precautions to include preoperative and postoperative cognitive testing, careful monitoring during anaesthesia, blood pressure control and early treatment of postoperative complications as they arise. In this review, we provide an update on the current understanding of the pathophysiology leading to POCD, identifying risk factors, prevention and treatment strategies, with a specific focus on the elderly population.

Early detection of cognitive impairment in patients with insulinoma

PURPOSE

Long-standing hypoglycemia can cause cognitive impairment, and whether recurrent severe hypoglycemia impacts cognitive function in patients with insulinoma has not been studied. This study focused on exploring the cognitive function in patients with insulinoma.

METHODS

A prospective study was conducted to assess cognitive function in patients with insulinoma by administering the Montreal Cognitive Assessment (MoCA) questionnaire between January 2016 and July 2017, and patients with cognitive impairment were followed up to undergo the MoCA test 1 year after surgery. The MoCA scores after surgery were compared with the scores before surgery, and the associations between cognitive impairment and relevant factors were further evaluated by multiple linear regression analysis.

RESULTS

Eighteen out of thirty-four patients (53%) with insulinoma were screened positive for cognitive impairment as defined by a MoCA score <26. Performance in certain cognitive domains, including visuospatial and executive functions, delayed memory, attention, language, and abstraction, was significantly worse in patients with cognitive impairment. Multivariate analysis indicated that MoCA scores correlated significantly with tumor grade and years of education. Eight patients with cognitive impairment were lost to follow-up. The remaining ten patients with cognitive impairment showed improvements 1 year postoperatively, and seven patients recovered to normal cognitive function.

CONCLUSIONS

Cognitive impairment was found in patients with insulinoma and was reversible in some patients 1 year after surgery. More studies are needed to explore the underlying mechanisms of the existence and reversibility of cognitive impairment in patients with insulinoma.

Delirium after primary percutaneous coronary intervention in aged individuals with acute ST-segment elevation myocardial infarction: A retrospective study

The present prospective study aimed to investigate the incidence and risk factors of delirium after primary percutaneous coronary intervention (PCI) in older adults with acute ST-segment elevation myocardial infarction (STEMI). A total of 111 patients (age, ≥65 years) with acute STEMI following primary PCI were included in the present study. Neurocognitive testing was performed using the Mini-mental State Examination on the first day of hospitalization. Post-operative delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit within the first four post-operative days. A total of 32 patients (28.8%) developed delirium after primary PCI. The independent predictors of delirium were older age [odds ratio (OR)=1.192, 95% confidence interval (CI)=1.07-1.328, P=0.001], living alone (OR=4.827, 95% CI=1.315-17.725, P=0.018), history of alcohol abuse (OR=3.875, 95% CI=1.168-12.857, P=0.026), longer duration of primary PCI (OR=1.152, 95% CI=1.077-1.232, P<0.001) and post-operative pain (current pain; OR=7.663, 95% CI=1.432-41.02, P=0.017). Compared to the patients without delirium, the participants who developed delirium had longer hospital stays and a higher rate of re-admission within 30 days after discharge. The mortality within one year after discharge (one-year mortality) was similar between patients with and without delirium. In conclusion, older patients (age, ≥65 years) with acute STEMI are at a relatively high risk of delirium following primary PCI. Higher age (≥65 years), living alone, history of alcohol dependence, longer length of primary PCI (>50 min) and post-operative pain (current pain) were determined to be risk factors for delirium after primary PCI in the present cohort.

Effect of preoperative inhaled budesonide on pulmonary injury after cardiopulmonary bypass: A randomized pilot study

BACKGROUND

Cardiopulmonary bypass can result in lung injury. This prospective, double-blinded, randomized trial aimed to evaluate the protective effect of inhaled budesonide on lung injury after cardiopulmonary bypass.

METHODS

Sixty patients, aged 25 to 65 years, requiring cardiopulmonary bypass were randomized to groups treated with saline or budesonide inhalation preoperatively. The respiratory mechanics were recorded. Bronchoalveolar lavage fluid was collected before cardiopulmonary bypass and after sternal closure. Serum and bronchoalveolar lavage fluid levels of proinflammatory and anti-inflammatory factors were analyzed. The primary end point was the lowest ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen after cardiopulmonary bypass. The durations of ventilation and postoperative recovery time were noted.

RESULTS

Budesonide significantly improved respiratory mechanics after cardiopulmonary bypass. Budesonide improved the partial pressure of arterial oxygen to the fraction of inspired oxygen ratio from 8 to 48 hours after the operation. Budesonide shortened the durations of mechanical ventilation and postoperative recovery time. Budesonide decreased the levels of proinflammatory factors while increasing the levels of anti-inflammatory factors in bronchoalveolar lavage fluid and serum (all P < .05). The macrophage and neutrophil counts, and protein and elastase concentrations were decreased by budesonide treatment.

CONCLUSIONS

Budesonide treatment shortened the durations of mechanical ventilation, inhibited local and systemic inflammation, and improved respiratory function after cardiopulmonary bypass.