Protocol for an observational study of delirium in the post-anaesthesia care unit (PACU) as a potential predictor of subsequent postoperative delirium

The Effects of Lateral 45° Head-Down Position and Carbon Dioxide Pneumoperitoneum on the Optic Nerve Sheath Diameter in Patients Undergoing Laparoscopic Transperitoneal Nephrectomies: A Prospective Observational Study

Background: The aim of this study is to assess the extent of the increased intracranial pressure resulting from lateral decubitus and 45° downward positioning using sonographic optic nerve sheath diameter (ONSD) in patients undergoing laparoscopic transperitoneal nephrectomy. In addition, we evaluated the effect of the carbon dioxide pneumoperitoneum (CO₂PP) on ONSD. Materials and Methods: Twenty-four adults were enrolled in this prospective observational study. Longitudinal and transverse ONSDs were measured for each eye by ocular ultrasonography. The values were noted in supine position (T0), 20 minutes after induction of anesthesia (T1), after insufflation of the abdomen in lateral 45° head-down position (T2), at 30-minute intervals during surgery (T3-T4-T5), during lateral 45° head-down position after CO₂ exsufflation (T6), before awakening while supine (T7), and at postoperative 24th hour (T8). Hemodynamic and respiratory parameters were investigated at the measurement time points. Results: Average ONSD values for the lower eye was T0 = 4.27 ± 0.4 mm, T1 = 4.56 ± 0.6 mm, T2 = 4.84 ± 0.6 mm, T3 = 4.91 ± 0.4 mm, T4 = 4.99 ± 0.5 mm, T5 = 4.97 ± 0.5 mm T6 = 4.96 ± 0.5 mm, T7 = 4.76 ± 0.4 mm, T8 = 4.36 ± 0.5 mm and for the upper eye was T0 = 4.24 ± 0.4 mm, T1 = 4.39 ± 0.5 mm, T2 = 4.54 ± 0.5 mm, T3 = 4.60 ± 0.4 mm, T4 = 4.66 ± 0.4 mm, T5 = 4.72 ± 0.7 mm, T6 = 4.68 ± 0.4 mm, T7 = 4.52 ± 0.4 mm, T8 = 4.30 ± 0.4 mm (P < .001). Conclusion: In our study, we observed a significant increase in ONSD within minutes after the patient was placed in a head-down position. We also observed that the difference increased more with CO₂PP and was proportional to the length of the surgery. We found that it regressed to initial levels at the postoperative 24th hour. Clinicaltrials.gov: NCT05185908.

Instruments to Identify Delirium in Patients Recovering From Anesthesia: A Scoping Review

PURPOSE

To identify the validated instruments used for screening and detecting postoperative delirium (POD) during Post Anesthesia Recovery (PAR) period, and the incidence and associated risk factors with POD.

DESIGN

A scoping review.

METHODS

The study search occurred in May 2021 in the PubMed, Embase, Scopus, CINAHL, Web of Science and LILACS databases. Primary studies that used validated instruments for screening and detecting POD in the PAR period were included.

FINDINGS

A total of 38 articles were included. The most used instruments were CAM-ICU, Nu-DESC, and RASS. The instruments that screened and detected delirium earliest were the Nu-DESC and CAM-ICU. POD incidence was up to 20% in more than half of the included studies. Cardiovascular comorbidities, chronic kidney disease, low functional reserve, chronic obstructive pulmonary disease and postoperative pain were among the primary risk factors.

CONCLUSION

The instrumentsshowing the greatest accuracy for screening and detecting POD in the PAR period were the Nu-DESC and CAM-ICU.

Emergence Delirium in Elderly Patients as a Potential Predictor of Subsequent Postoperative Delirium: A Descriptive Correlational Study

PURPOSE

This study aimed to investigate the incidence of emergence delirium (ED) in elderly patients under general anesthesia and to determine the correlation between ED and delirium at five subsequent postoperative days.

DESIGN

This research is a descriptive correlational study.

METHODS

A total of 168 aged patients undergoing elective general anesthesia were recruited from a comprehensive tertiary teaching hospital with 2,400 beds in Southern China from April 2018 to September 2018. The Nursing Delirium Screening Scale was used to assess delirium at 30 and 60 minutes after extubation or on discharge from the postanesthesia care unit. Patients were assessed for delirium at postoperative days one through five using the same method. Patients' demographic information, including cognitive function, were collected.

FINDINGS

Among the 168 aged patients, 58 suffered from ED (34.5%), including the 79.3% for the 46 patients who experienced postoperative delirium (POD). A positive correlation existed between ED and POD (χ² = 111.744; P < .01). Logistic regression analysis included seven variables: age, preoperative Mini-Mental State Examination score, underlying diseases, American Society of Anesthesiologists grade, surgery duration, postoperative complications, and the presence of ED. Age and ED were concluded to be independent predictive factors of POD.

CONCLUSIONS

ED in the first hour after tracheal tube removal is a predictor of delirium at five subsequent postoperative days. Accurate and timely assessment of recovery period can effectively guide the treatment and rehabilitation of POD and maximize prevention of adverse consequences.

Home-based Cognitive Prehabilitation in Older Surgical Patients: A Feasibility Study

BACKGROUND

Cognitive training is beneficial in various clinical settings, although its perioperative feasibility and impact remain unknown. The objective of this pilot study was to determine the feasibility of home-based cognitive prehabilitation before major surgery in older adults.

MATERIALS AND METHODS

Sixty-one patients were enrolled, randomized, and allocated to either a home-based preoperative cognitive training regimen or no training before surgery. Outcomes included postoperative delirium incidence (primary outcome; assessed with the 3D-Confusion Assessment Method), perioperative cognitive function based on NIH Toolbox measures, hospital length of stay, and physical therapy session participation. Reasons for declining enrollment were reported, as were reasons for opting out of the training program.

RESULTS

Postoperative delirium incidence was 6 of 23 (26%) in the prehabilitation group compared with 5 of 29 (17%) in the control group (P=0.507). There were no significant differences between groups in NIH Toolbox cognitive function scoring, hospital length of stay, or physical therapy participation rates. Study feasibility data were also collected and reported. The most common reasons for declining enrollment were lack of computer access (n=19), time commitment (n=9), and feeling overwhelmed (n=9). In the training group, only 5 of 29 (17%) included patients were able to complete the prescribed 7 days of training, and 14 of 29 (48%) opted out of training once home. Most common reasons were feeling overwhelmed (n=4) and computer difficulties (n=3).

CONCLUSIONS

Short-term, home-based cognitive training before surgery is unlikely to be feasible for many older patients. Barriers to training include feeling overwhelmed, technical issues with training, and preoperative time commitment.

General Anesthesia Does Not Have Persistent Effects on Attention in Rodents

Background: Studies in animals have shown that general anesthesia can cause persistent spatial memory impairment, but the influence of anesthetics on other cognitive functions is unclear. This study tested whether exposure to general anesthesia without surgery caused a persistent deficit in attention in rodents.

Methods: To evaluate whether anesthesia has persistent effects on attention, rats were randomized to three groups. Group A was exposed for 2 h to isoflurane anesthesia, and tested the following seven days for attentional deficits. Group B was used as a control and received room air before attentional testing. Since there is some evidence that a subanesthetic dose of ketamine can improve cognition and reduce disorders of attention after surgery, rats in group C were exposed to isoflurane anesthesia in combination with a ketamine injection before cognitive assessment. Attention was measured in rats using the 5-Choice Serial Reaction Time Task, for which animals were trained to respond with a nose poke on a touchscreen to a brief, unpredictable visual stimulus in one of five possible grid locations to receive a food reward. Attention was analyzed as % accuracy, % omission, and premature responses.

Results: Evaluating acute attention by comparing baseline values with data from the day after intervention did not reveal any differences in attentional measurements. No significant differences were seen in % accuracy, % omission, and premature responses for the three groups tested for 7 consecutive days.

Conclusion: These data in healthy rodents suggest that general anesthesia without surgery has no persistent effect on attention and the addition of ketamine does not alter the outcome.

Dexmedetomidine and intravenous acetaminophen for the prevention of postoperative delirium following cardiac surgery (DEXACET trial): protocol for a prospective randomized controlled trial

Background

Postoperative delirium is common in elderly cardiac surgery patients. It is multifactorial and is influenced by the patient’s baseline status and the nature of the medical and surgical interventions that the patient receives. Some of these factors are potentially modifiable, including postoperative sedation and analgesia protocols. This study has been designed to evaluate the effectiveness of postoperative intravenous acetaminophen in conjunction with either dexmedetomidine or propofol in decreasing the incidence of delirium.

Methods

This is a prospective, randomized, placebo-controlled, double-blinded, factorial trial that includes patients who are at least 60 years old and who are undergoing cardiac surgeries involving cardiopulmonary bypass, including coronary artery bypass graft (CABG) and combined CABG/valve surgeries. Patients are randomly assigned to receive one of four postoperative analgesic-sedation regimens: (1) acetaminophen and dexmedetomidine, (2) acetaminophen and propofol, (3) dexmedetomidine and placebo, or (4) propofol and placebo. The primary outcome, incidence of delirium, will be assessed with the Confusion Assessment Method (CAM or CAM-ICU). The secondary outcome, postoperative cognitive decline, will be assessed with the Montreal Cognitive Assessment. Additional secondary outcomes, including duration of delirium, postoperative analgesic requirement, length of stay, and incidence of adverse events, will also be reported. Data will be analyzed in 120 randomly assigned patients who received at least one dose of the study medication(s) on a modified intention-to-treat basis.

Discussion

This study has been approved by the institutional review board at Beth Israel Deaconess Medical Center, and the trial is currently recruiting. This study will systematically examine the implications of modification in postoperative sedative/analgesic protocols after cardiac surgery, specifically for short- and long-term cognitive outcomes. Any positive outcomes from this study could direct simple yet effective practice changes aimed to reduce morbidity.

Trial registration

ClinicalTrials.gov Identifier: NCT02546765, registered January 13, 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2718-0) contains supplementary material, which is available to authorized users.

The use of dexmedetomidine and intravenous acetaminophen for the prevention of postoperative delirium in cardiac surgery patients over 60 years of age: a pilot study

Background: Delirium is associated with many negative health outcomes. Postoperative sedation and opioid administration may contribute to delirium. We hypothesize that the use of dexmedetomidine and Intravenous acetaminophen (IVA) may lead to reduced opioid consumption and decreased incidence of postoperative delirium. This pilot study aims to assess feasibility of using dexmedetomidine and IVA in cardiac surgical patients, and estimate the effect size for incidence and duration of delirium.

Methods: A total of 12 adult patients >60 years of age undergoing cardiac surgery were recruited and randomized into 4 groups: Propofol only (P), Propofol with IVA (P+A), Dexmedetomidine only (D), Dexmedetomidine with IVA (D+A). Preoperative baseline cognition and postoperative delirium was assessed daily until discharge. The feasibility was assessed by the number of patients who completed the study.

Results: All patients completed the study successfully. The total incidence of delirium in the study population was 42% (5/12):  67% (2/3) in the group P, and 67% (2/3) in the group D, 33% (1/3) in  D+A group and 0%(0/3)  P+A group. The incidence of delirium was 17% (1/6) in the group receiving IVA compared to 67% (4/6) that did not receive IVA. The mean range of duration of delirium was 0-1 days. One patient expired after surgery, unrelated to the study protocol. One patient in the D group experienced hypotension (systolic blood pressure <90 mm of Hg.)

Conclusions: The feasibility of performing a  project is ascertained by the study. Patients receiving IVA had lower incidence of delirium compared to patients not receiving IVA which suggests that IVA may have a role in reducing the incidence of delirium. A prospective randomized, placebo-controlled trial will be the next step in investigating the role of dexmedetomidine and IVA in reducing the incidence of delirium.