Risk factors of post-anaesthesia care unit delirium in patients undergoing non-cardiac surgery in Singapore.

Introduction: Post-anaesthesia care unit (PACU) delirium affects 5%-45% of patients after surgery and is associated with postoperative delirium and increased mortality. Up to 40% of PACU delirium is preventable, but it remains under-recognised due to a lack of awareness of its diagnosis. The nursing delirium screening scale (Nu-DESC) has been validated for diagnosing PACU delirium, but is not routinely used locally. This study aimed to use Nu-DESC to establish the incidence and risk factors of PACU delirium in patients undergoing non-cardiac surgery in the surgical population. Methods: We conducted an audit of eligible patients undergoing major surgery in three public hospitals in Singapore over 1 week. Patients were assessed for delirium 30-60 min following their arrival in PACU using Nu-DESC, with a total score of ≥2 indicative of delirium. Results: A total of 478 patients were assessed. The overall incidence rate of PACU delirium was 18/478 (3.8%), and the incidence was 9/146 (6.2%) in patients aged > 65 years. Post-anaesthesia care unit delirium was more common in females, patients with malignancy and those who underwent longer operations. Logistic regression analysis showed that the use of bispectral index (P < 0.001) and the presence of malignancy (P < 0.001) were significantly associated with a higher incidence of PACU delirium. Conclusion: In this first local study, the incidence of PACU delirium was 3.8%, increasing to 6.2% in those aged > 65 years. Understanding these risk factors will form the basis for which protocols can be established to optimise resource management and prevent long-term morbidities and mortality in PACU delirium.

Incidence and risk factors of delirium in post-anaesthesia care unit.

INTRODUCTION: Post-anaesthesia care unit (PACU) delirium is a potentially preventable condition that results in a significant long-term effect. In a multicentre prospective cohort study, we investigate the incidence and risk factors of postoperative delirium in elderly patients undergoing major non-cardiac surgery. METHODS: Patients were consented and recruited from 4 major hospitals in Singapore. Research ethics approval was obtained. Patients older than 65 years undergoing non-cardiac surgery >2 hours were recruited. Baseline perioperative data were collected. Preoperative baseline cognition was obtained. Patients were assessed in the post-anaesthesia care unit for delirium 30-60 minutes after arrival using the Nursing Delirium Screening Scale (Nu-DESC). RESULTS: Ninety-eight patients completed the study. Eleven patients (11.2%) had postoperative delirium. Patients who had PACU delirium were older (74.6±3.2 versus 70.6±4.4 years, P=0.005). Univariate analysis showed those who had PACU delirium are more likely to be ASA 3 (63.6% vs 31.0%, P=0.019), had estimated glomerular filtration rate (eGFR) of >60mL/min/1.73m2 (36.4% vs 10.6%, P=0.013), higher HbA1C value (7.8±1.2 vs 6.6±0.9, P=0.011), raised random blood glucose (10.0±5.0mmol/L vs 6.5±2.4mmol/L, P=0.0066), and moderate-severe depression (18.2% vs 1.1%, P=0.033). They are more likely to stay longer in hospital (median 8 days [range 4-18] vs 4 days [range 2-8], P=0.049). Raised random blood glucose is independently associated with increased PACU delirium on multivariate analysis.

Intraoperative Celiac Plexus Block With Preperitoneal Infusion Reduces Opioid Usage in Major Hepato-pancreato-biliary Surgery: A Pilot Study.

OBJECTIVE: Given the role of celiac plexus block (CPB) in the management of chronic pain, we sought to investigate the utility of CPB in the control of postoperative pain in major hepato-pancreato-biliary surgeries. SUMMARY BACKGROUND DATA: CPB has been in practice for decades for the management of upper abdominal visceral pain, especially in cancer patients. Typically, in this group of patients with chronic pain, a neurolytic agent is injected to cause irreversible neural damage to achieve pain control. We apply this concept to postoperative pain control by injecting bupivacaine to the celiac plexus instead of a neurolytic agent. We aim to investigate if this novel technique decreases postoperative opioid usage, offers better pain relief and leads to earlier ambulation. METHODS: A retrospective, single institution study comparing consecutive patients who received intraoperative CPB and preperitoneal infusion with patients who received only preperitoneal infusion in open hepato-pancreato-biliary surgery between the years 2016 and 2019 by a single surgeon. Patients with incomplete data on patient-controlled analgesia usage and postoperative ambulation information were excluded. RESULTS: Patients with CPB used 31% less morphine on postoperative day 1 compared to patient without CPB and 42% less morphine on postoperative day 2. Overall average morphine usage was significantly lower in patients with CPB. Duration of patient-controlled analgesia was shorter for patient with CPB compared with patient without CPB. The dynamic visual analogue score was marginally better in patients with CPB. Time to ambulation was similar in both groups. CONCLUSIONS: CPB can be considered as part of a multimodal approach for postoperative pain management in open hepato-pancreato-biliary surgeries.

The Importance of the Saphenous Nerve Block for Analgesia Following Major Ankle Surgery: A Randomized, Controlled, Double-Blind Study.

BACKGROUND AND OBJECTIVES: Major ankle surgery causes intense postoperative pain, and whereas the importance of a sciatic nerve block is well established, the clinical significance of a supplemental saphenous nerve block has never been determined in a prospective, randomized, double-blind, placebo-controlled trial. We hypothesized that a saphenous nerve block reduces the proportion of patients experiencing significant clinical pain after major ankle surgery. METHODS: Eighteen patients were enrolled and received a popliteal sciatic nerve block. Patients were randomized to single-injection saphenous nerve block with 10 mL 0.5% bupivacaine with 1:200,000 epinephrine or 10 mL saline (Fig. 1). Primary outcome was the proportion of patients reporting significant clinical pain, defined as a score greater than 3 on the numerical rating scale. Secondary outcomes were maximal pain and analgesia of the cutaneous territory of the infrapatellar branch of the saphenous nerve. RESULTS: Eight of 9 patients in the placebo group reported significant clinical pain versus 1 of 9 patients in the bupivacaine-epinephrine group (P = 0.003). Maximal pain was significantly lower in the active compared with the placebo group (median, 0 [0-0] vs 5 [4-6]; P = 0.001). Breakthrough pain from the saphenous territory began within 30 minutes after surgery in all cases. Sensory testing of the cutaneous territory of the infrapatellar branch of the saphenous nerve showed correlation between pain reported in the anteromedial ankle region and the intensity of cutaneous sensory block in the anteromedial knee region. CONCLUSIONS: The saphenous nerve is an important contributor to postoperative pain after major ankle surgery, with significant clinical pain appearing within 30 minutes after surgery. CLINICAL TRIALS REGISTRATION: This study has been registered at ClinicalTrials.gov, identifier NCT02697955.

Defining the Location of the Adductor Canal Using Ultrasound.

BACKGROUND AND OBJECTIVES: The precise location of the adductor canal remains controversial among anesthesiologists. In numerous studies of the analgesic effect of the so-called adductor canal block for total knee arthroplasty, the needle insertion point has been the midpoint of the thigh, determined as the midpoint between the anterior superior iliac spine and base of patella. "Adductor canal block" may be a misnomer for an approach that is actually an injection into the femoral triangle, a "femoral triangle block." This block probably has a different analgesic effect compared with an injection into the adductor canal. We sought to determine the exact location of the adductor canal using ultrasound and relate it to the midpoint of the thigh. METHODS: Twenty-two volunteers were examined using ultrasound. The proximal end of the adductor canal was identified where the medial border of the sartorius muscle intersects the medial border of the adductor longus muscle. The distal end of the adductor canal is the adductor hiatus, which was also visualized ultrasonographically. RESULTS: The mean distance from the anterior superior iliac spine to the midpoint of the thigh was 22.9 cm (range, 20.3-24.9 cm). The mean distance from the anterior superior iliac spine to the proximal end of the adductor canal was 27.4 cm (range, 24.0-31.4 cm). Consequently, the mean distance from the midpoint of the thigh to the proximal end of the adductor canal was 4.6 cm (range, 2.3-7.0 cm). CONCLUSIONS: In all volunteers, the midpoint of the thigh was proximal to the beginning of the adductor canal, suggesting that an injection performed at this level is in fact a femoral triangle block.