Perioperative association between c-reactive protein, pain catastrophizing and acute pain after total knee arthroplasty: A secondary analysis of two randomised trials.

BACKGROUND: Total knee arthroplasty is associated with an inflammatory response and high levels of pain in a subset of patients. Pain catastrophizing has been associated with acute postoperative pain. The association between these variables has not been investigated in an optimised fast-track setup including preoperative glucocorticoids. The aim of this study was, first, to investigate the correlation between the increase in postoperative c-reactive protein (CRP) and acute postoperative pain after total knee arthroplasty, and second, to investigate the correlation between the increase in CRP and preoperative pain catastrophizing. METHODS: This study is a secondary analysis of data from 119 patients participating in two randomised controlled trials. Correlation analyses were performed for preoperative CRP and CRP increase at 24 and 48 h and pain during a well-defined mobilisation at 24 and 48 h after total knee arthroplasty. Additionally, correlation analyses were performed between CRP increase and pain catastrophizing using the pain catastrophizing scale. RESULTS: There was no correlation between preoperative CRP or postoperative CRP increase and pain at both 24 and 48 h. Analyses were similar when separated into high and low pain catastrophizers. There was no correlation between preoperative CRP or postoperative CRP increase and pain catastrophizing. CONCLUSION: There was no association between the postoperative CRP response and postoperative acute pain or pain catastrophizing in patients undergoing total knee arthroplasty in a well-defined multimodal fast-track regime including preoperative glucocorticoids. These results suggest that acute pain after knee arthroplasty is not reflected by CRP when applying preoperative glucocorticoids.

Predictors of subacute postoperative pain after total knee arthroplasty: A secondary analysis of two randomized trials.

BACKGROUND: Methods for identifying high-pain responders undergoing total knee arthroplasty remain important to improve individualized pain management. This study aimed at evaluating pre- and perioperative predictors of pain on Days 2-7 after total knee arthroplasty. METHODS: This is a secondary analysis of data from 227 patients participating in two randomized trials. Pain outcomes were mean pain during walking on Days 2-7 and on Days 2, 4 and 7. Multivariable linear and logistic regressions were carried out in two steps. First, only preoperative available variables including demographics, comorbidities, pain catastrophizing scale and preoperative pain were evaluated while controlling for trial intervention and recruitment site. In the second step, perioperative variables and pain during walking 24 h postoperatively were added. RESULTS: The model with only preoperative predictors for mean pain Days 2-7 showed preoperative pain (R-squared 0.097) as the only predictor. In the second model, adding postoperative available variables, only pain 24 h postoperatively (R-squared 0.248) was significant, with a significant main effect of recruitment site. Results for the separate day analysis similarly showed preoperative pain and pain during walking 24 h postoperatively as predictors. The overall best sensitivity (60%) and specificity (74%) for predicting a high-subacute postoperative pain response on Days 2-7 was with cut-off values of VAS 45.5 (out of 100) for pain during walking 24 h postoperatively. CONCLUSIONS: Postoperative pain during walking at 24 h is predictive of subacute postoperative pain on Days 2-7 after total knee arthroplasty, while preoperative pain was only a weak predictor. SIGNIFICANCE STATEMENT: This study investigated factors associated with pain after total knee arthroplasty beyond the immediate postoperative period. The analysis revealed significant associations between preoperative pain levels and, particularly, pain 24 h postoperatively, with subsequent subacute pain the following week. These findings can assist in identifying patients who would benefit from enhanced, individualized analgesic interventions to facilitate postoperative recovery.

Preoperative high dose of dexamethasone in emergency laparotomy: randomized clinical trial.

BACKGROUND: Patients undergoing emergency laparotomy present with a profound inflammatory response, which could be an independent pathophysiological component in prolonged recovery. The aim of this study was to investigate the effects of a single preoperative high dose of intravenous dexamethasone on the inflammatory response and recovery after emergency laparotomy. METHODS: In this double-blinded placebo-controlled trial, patients were prospectively stratified according to surgical pathology (intestinal obstruction and perforated viscus) and randomized to preoperative 1 mg/kg dexamethasone or placebo at a ratio of 1 : 1. The primary outcome was C-reactive protein on postoperative day 1. Secondary outcomes were postoperative recovery, morbidity, and mortality. RESULTS: A total of 120 patients were included in the trial. On postoperative day 1, the C-reactive protein response was significantly lower in the dexamethasone group (a median of 170 versus 220 mg/l for dexamethasone and for placebo respectively; P = 0.015; mean difference = 49 (95% c.i. 13 to 85) mg/l) and when stratified according to intestinal obstruction (a median of 60 versus 160 mg/l for dexamethasone and for placebo respectively; P = 0.002) and perforated viscus (a median of 230 versus 285 mg/l for dexamethasone and for placebo respectively; P = 0.035). Dexamethasone administration was associated with improved recovery (better haemodynamics, better pulmonary function, less fatigue, and earlier mobilization). Furthermore, the dexamethasone group had a lower 90-day mortality rate (7% versus 23% for dexamethasone and for placebo respectively; relative risk 0.33 (95% c.i. 0.11 to 0.93); P = 0.023) and a decreased incidence of postoperative major complications (27% versus 45% for dexamethasone and for placebo respectively; relative risk 0.62 (95% c.i. 0.37 to 1.00); P = 0.032). CONCLUSION: A single preoperative high dose of intravenous dexamethasone significantly reduces the inflammatory response after emergency laparotomy and is associated with enhanced recovery and improved outcome. REGISTRATION NUMBER: NCT04791566 (http://www.clinicaltrials.gov).

Peripheral perfusion index stratifies risk in patients with intraoperative anemia: A multicentre cohort study.

STUDY OBJECTIVE: Evidence for red blood cell (RBC) transfusion thresholds in the intraoperative setting is limited, and current perioperative recommendations may not correspond with individual intraoperative physiological demands. Hemodynamics relevant for the decision to transfuse may include peripheral perfusion index (PPI). The objective of this prospective study was to assess the associations of PPI and hemoglobin levels with the risk of postoperative morbidity and mortality. DESIGN: Multicenter cohort study. SETTING: Bispebjerg and Hvidovre University Hospitals, Copenhagen, Denmark. PATIENTS: We included 741 patients who underwent acute high risk abdominal surgery or hip fracture surgery. INTERVENTIONS: No interventions were carried out. MEASUREMENTS: Principal values collected included measurements of peripheral perfusion index and hemoglobin values. METHODS: The study was conducted using prospectively obtained data on adults who underwent emergency high-risk surgery. Subjects were categorized into high vs. low subgroups stratified by pre-defined PPI levels (PPI: > 1.5 vs. < 1.5) and Hb levels (Hb: > 9.7 g/dL vs. < 9.7 g/dL). The study assessed mortality and severe postoperative complications within 90 days. MAIN RESULTS: We included 741 patients. 90-day mortality was 21% (n = 154), frequency of severe postoperative complications was 31% (n = 231). Patients with both low PPI and low Hb had the highest adjusted odds ratio for both 90-day severe postoperative complications (2.95, [1.62-5.45]) and 90-day mortality (3.13, [1.45-7.11]). A comparison of patients with low PPI and low Hb to those with high PPI and low Hb detected significantly higher 90-day mortality risk in the low PPI and low Hb group (OR 8.6, [1.57-162.10]). CONCLUSION: High PPI in acute surgical patients who also presents with anemia was associated with a significantly better outcome when compared with patients with both low PPI and anemia. PPI should therefore be further investigated as a potential parameter to guide intraoperative RBC transfusion therapy.

Postoperative orthostatic intolerance following fast-track unicompartmental knee arthroplasty: incidence and hemodynamics-a prospective observational cohort study.

BACKGROUND: Early postoperative mobilization is essential for early functional recovery but can be inhibited by postoperative orthostatic intolerance (OI). Postoperative OI is common after major surgery, such as total knee arthroplasty (TKA). However, limited data are available after less extensive surgery, such as unicompartmental knee arthroplasty (UKA). We, therefore, investigated the incidence of OI as well as cardiovascular and tissue oxygenation responses during early mobilization after UKA. METHODS: This prospective single-centre observational study included 32 patients undergoing primary UKA. Incidence of OI and cardiovascular and tissue oxygenation responses during mobilization were evaluated preoperatively, at 6 and 24 h after surgery. Perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain during mobilization and opioid usage were recorded. RESULTS: During mobilization at 6 h after surgery, 4 (14%, 95%CI 4-33%) patients experienced OI; however, no patients terminated the mobilization procedure prematurely. Dizziness and feeling of heat were the most common symptoms. OI was associated with attenuated systolic and mean arterial blood pressure responses in the sitting position (all p < 0.05). At 24 h after surgery, 24 (75%) patients had already been discharged, including three of the four patients with early OI. Only five patients were available for measurements, two of whom experienced OI; one terminated the mobilization procedure due to intolerable symptoms. We observed no statistically significant differences in perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain, or opioid usage between orthostatic intolerant and tolerant patients. CONCLUSIONS: The incidence of orthostatic intolerance after fast-track unicompartmental knee arthroplasty is low (~ 15%) and is associated with decreased orthostatic pressure responses. Compared to the previously described orthostatic intolerance incidence of ~ 40% following total knee arthroplasty, early orthostatic intolerance is uncommon after unicompartmental knee arthroplasty, suggesting a procedure-specific component. TRIAL REGISTRATION: Prospectively registered at ClinicalTrials.gov; registration number: NCT04195360, registration date: 13.12.2019.

Orthostatic intolerance after acute mild hypovolemia: incidence, pathophysiologic hemodynamics, and heart-rate variability analysis-a prospective observational cohort study.

PURPOSE: Early postoperative mobilization can be hindered by orthostatic intolerance (OI). Postoperative OI has multifactorial pathogenesis, possibly involving both postoperative hypovolemia and autonomic dysfunction. We aimed to investigate the effect of mild acute blood loss from blood donation simulating postoperative hypovolemia, on both autonomic function and OI, thus eliminating confounding perioperative factors such as inflammation, residual anesthesia, pain, and opioids. METHODS: This prospective observational cohort study included 26 blood donors. Continuous electrocardiogram data were collected during mobilization and night sleep, both before and after blood donation. A Valsalva maneuver and a standardized mobilization procedure were performed immediately before and after blood donation, during which cardiovascular and tissue oxygenation variables were continuously measured by LiDCOrapid™ and Massimo Root™, respectively. The incidence of OI, hemodynamic responses during mobilization and Valsalva maneuver, as well as heart rate variability (HRV) responses during mobilization and sleep were compared before and 15 min after blood donation. RESULTS: Prior to blood donation, no donors experienced OI during mobilization. After blood donation, 6/26 (23%; 95% CI, 9 to 44) donors experienced at least one OI symptom. Three out of 26 donors (12%; 95% CI, 2 to 30) terminated the mobilization procedure prematurely because of severe OI symptoms. Cardiovascular and cerebral tissue oxygenation responses were reduced in patients with severe OI. After blood loss, HRV indices of total autonomic power remained unchanged but increased sympathetic and decreased parasympathetic outflow was observed during mobilization, but also during sleep, indicating a prolonged autonomic effect of hypovolemia. CONCLUSION: We describe a specific hypovolemic component of postoperative OI, independent of postoperative autonomic dysfunction, inflammation, opioids, and pain. STUDY REGISTRATION: ClinicalTrials.gov (NCT04499664); registered 5 August 2020.

RéSUMé: OBJECTIF: La mobilisation postopératoire précoce peut être entravée par une intolérance orthostatique (IO). L'IO postopératoire a une pathogenèse multifactorielle, impliquant peut-être à la fois une hypovolémie postopératoire et un dysfonctionnement autonome. Notre objectif était d'étudier l'effet d'une légère perte de sang aiguë due au don de sang simulant une hypovolémie postopératoire, à la fois sur la fonction autonome et sur l'IO, éliminant ainsi les facteurs périopératoires confondants tels que l'inflammation, l'anesthésie résiduelle, la douleur et les opioïdes. MéTHODE: Cette étude de cohorte observationnelle prospective comprenait 26 personnes ayant donné leur sang. Des données d'électrocardiogramme continu ont été recueillies pendant la mobilisation et le sommeil nocturne, avant et après le don de sang. Une manœuvre de Valsalva et une procédure de mobilisation standardisée ont été réalisées immédiatement avant et après le don de sang, au cours desquelles les variables d'oxygénation cardiovasculaire et tissulaire ont été mesurées en continu avec les moniteurs LiDCOrapid™ et Massimo Root™, respectivement. L'incidence d'IO, les réponses hémodynamiques pendant la mobilisation et la manœuvre de Valsalva, ainsi que les réponses de variabilité de la fréquence cardiaque (VFC) pendant la mobilisation et le sommeil ont été comparées avant et 15 minutes après le don de sang. RéSULTATS: Avant le don de sang, aucune personne ayant fait un don de sang n'a ressenti d'IO pendant la mobilisation. Après le don de sang, 6/26 (23 %; IC 95 %, 9 à 44) des donneurs et donneuses ont manifesté au moins un symptôme d'IO. Trois personnes sur 26 (12 %; IC 95 %, 2 à 30) ont interrompu prématurément la procédure de mobilisation en raison de symptômes graves d'IO. Les réponses d'oxygénation des tissus cardiovasculaires et cérébraux ont été réduites chez les personnes atteintes d'IO sévère. Après la perte de sang, les indices de VFC de la puissance totale autonome sont demeurés inchangés, mais une augmentation du flux sympathique et une diminution du flux parasympathique ont été observées pendant la mobilisation, mais également pendant le sommeil, indiquant un effet autonome prolongé de l'hypovolémie. CONCLUSION: Nous décrivons une composante spécifique hypovolémique de l'IO postopératoire, indépendante du dysfonctionnement autonome postopératoire, de l'inflammation, des opioïdes et de la douleur. ENREGISTREMENT DE L'éTUDE: www.ClinicalTrials.gov (NCT04499664); enregistrée le 5 août 2020.

Psychological predictors of acute postoperative pain after total knee and hip arthroplasty: A systematic review.

BACKGROUND: Identifying patients at high risk of acute postoperative pain after total knee or hip arthroplasty (TKA/THA) will facilitate individualized pain management and research on the efficacy of treatment options. Numerous studies have reported that psychological patient factors may influence acute postoperative pain, but most reviews have focused on chronic pain and functional outcomes. This systematic review aims to evaluate which psychological metrics are associated with acute postoperative pain after TKA and THA. METHODS: A systematic search was conducted using the databases PubMed, EMBASE, Web of Science, and Cochrane Library until June 2022. Full-text articles reporting associations of preoperative psychological factors with acute pain within 48 h of TKA or THA surgery were identified. Quality was assessed using the Quality in Prognostic Studies tool. RESULTS: Eighteen studies containing 16 unique study populations were included. TKA was the most common procedure, and anxiety and depression were the most evaluated psychological metrics. Several different anesthetic techniques and analgesic regimens were used. The studies were generally rated as having a low to moderate risk of bias. Catastrophizing was associated with acute pain in six studies (of nine), mainly after TKA. In contrast, three studies (of 13) and two studies (of 13) found anxiety and depression, respectively, to be associated with acute postoperative pain. CONCLUSION: Pain catastrophizing seemed to be the most consistent psychological predictor of acute postoperative pain after TKA. The results for other psychological factors and THA were inconsistent. However, the interpretation of results was limited by considerable methodological heterogeneity.

High dose dexamethasone in high pain responders undergoing total hip arthroplasty: A randomized controlled trial.

BACKGROUND: Postoperative pain after total hip arthroplasty (THA) may delay postoperative mobilization and discharge. Postoperative pain has been shown to be higher in pain catastrophisers and patients receiving opioids. A single dose of glucocorticoid reduces pain after THA, and an increased dose of glucocorticoids has been found to be effective in patients at high risk of postoperative pain after total knee arthroplasty (TKA), however, the ideal dose in THA remains unknown. OBJECTIVE: To evaluate the effect of a high dose (1 mg kg -1 ) vs. intermediate dose (0.3 mg kg -1 ) of dexamethasone on pain after THA. DESIGN: A randomized double-blind controlled study. SETTING: A two-centre study including two large arthroplasty sites in Denmark was conducted from February 2019 to August 2020. PATIENTS: A total of 160 patients undergoing THA by neuraxial block with multimodal analgesia, having a Pain Catastrophising Scale score >20 and/or preoperative opioid use were included. INTERVENTION: Patients were randomly assigned to receive dexamethasone 1 mg kg -1 or 0.3 mg kg -1 before THA. MAIN OUTCOME MEASURES: Primary outcome was percentage of patients experiencing moderate to severe pain (visual analogue scale, VAS > 30 mm on a 0 to 100 mm scale) on ambulating 24 h after surgery. Secondary outcomes included cumulated pain scores, C-reactive protein (CRP), opioid use, postoperative recovery scores, length of stay, complications, and re-admission within 30 and 90 days. RESULTS: No difference was found in percentage of VAS >30 mm 24 h after surgery in the 5-m walk test (VAS > 30/VAS ≤ 30%); 33/42 (44%) vs. 32/43 (43%), relative risk = 1.04 (95% confidence interval 0.72-1.51; P  = 0.814) in 1 mg kg -1vs. 0.3 mg kg -1 respectively. No differences were found in CRP and opioid use between groups. Also, no intergroup differences were found in recovery scores, re-admissions, or complications. CONCLUSION: 1 mg kg -1vs. 0.3 mg kg -1 dexamethasone improved neither postoperative pain nor recovery in THA in a cohort of predicted high pain responders. TRIAL REGISTRATION: ClinicalTrials.gov ID-number NCT03763760 and EudraCT-number 2018-2636-25.

Associations between clinical interventions and transcutaneous blood gas values in postoperative patients.

PURPOSE: Postoperative monitoring of circulation and respiration is pivotal to guide intervention strategies and ensure patient outcomes. Transcutaneous blood gas monitoring (TCM) may allow for noninvasive assessment of changes in cardiopulmonary function after surgery, including a more direct assessment of local micro-perfusion and metabolism. To form the basis for studies assessing the clinical impact of TCM complication detection and goal-directed-therapy, we examined the association between clinical interventions in the postoperative period and changes in transcutaneous blood gasses. METHODS: Two-hundred adult patients who have had major surgery were enrolled prospectively and monitored with transcutaneous blood gas measurements (oxygen (TcPO2) and carbon dioxide (TcPCO2)) for 2 h in the post anaesthesia care unit, with recording of all clinical interventions. The primary outcome was changes in TcPO2, secondarily TcPCO2, from 5 min before a clinical intervention versus 5 min after, analysed with paired t-test. RESULTS: Data from 190 patients with 686 interventions were analysed. During clinical interventions, a mean change in TcPO2 of 0.99 mmHg (95% CI-1.79-0.2, p = 0.015) and TcPCO2 of-0.67 mmHg (95% CI 0.36-0.98, p < 0.001) was detected. CONCLUSION: Clinical interventions resulted in significant changes in transcutaneous oxygen and carbon dioxide. These findings suggest future studies to assess the clinical value of changes in transcutaneous PO2 and PCO2 in a postoperative setting. TRIAL REGISTRY: Clinical trial number: NCT04735380. CLINICAL TRIAL REGISTRY: https://clinicaltrials.gov/ct2/show/NCT04735380.

Repeat dose steroid in high pain responders after total knee arthroplasty: A study protocol.

Pain after total knee arthroplasty (TKA) is a well-known clinical problem potentially delaying ambulation and recovery. Perioperative glucocorticoids reduce pain and facilitate early recovery, but the optimal timing and dose are still unknown. High pain catastrophizers have an increased risk of poorly controlled postoperative pain, and moderate to severe pain at 24 h is associated with a risk of pain relapse at 48 h. To evaluate the effect of a repeat moderate dose of glucocorticoids after TKA in high pain catastrophizers presenting with moderate to severe pain 24 h postoperatively, having received preoperative high-dose glucocorticoids. High pain catastrophizers (Pain Catastrophizing Scale > 20) undergoing TKA are screened 24 h postoperatively and are included if they experience moderate to severe pain (VAS > 30) during a 5 m walk test. The included patients will receive either oral 24 mg dexamethasone (n = 55) or placebo (n = 55) on the evening of Day 1 (~30-37 h) after surgery. In addition, patients receive a standard multimodal analgesic regimen, including paracetamol, celecoxib, local infiltration analgesia, and preoperative dexamethasone (1 mg/kg). Patients will fill out a pain diary for 7 days after surgery. The primary outcome is moderate to severe pain (VAS > 30) during a 5 m walk test on the morning of Day 2 after surgery. The secondary outcomes include cumulated pain at rest and during ambulation, cumulated use of rescue analgesics, quality of sleep, lethargy, dizziness, nausea, satisfaction with the analgesic regimen, length of stay, morbidity, mortality, and reasons for readmissions. Follow-up is at 8 and 30 days. The data from this study will provide evidence for the effect of a repeated dose of dexamethasone as an analgesic adjuvant in patients undergoing TKA with a high risk of postoperative pain.

High-dose dexamethasone in low pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

BACKGROUND: Postoperative pain after total knee arthroplasty (TKA) is a continuing problem despite optimised multimodal analgesia. Previous studies have shown preoperative glucocorticoids to reduce postoperative pain, but knowledge about specific doses and effects in specific patient groups is lacking. METHODS: A two-centre, double-blind, two-arm study comparing preoperative dexamethasone (1 mg kg-1vs 0.3 mg kg-1 i.v.) on postoperative pain in 160 planned TKA subjects with low preoperative pain catastrophising and no opioid use. Subjects received multimodal analgesia with paracetamol, cyclooxygenase-2 inhibitors, local anaesthetic infiltration analgesia, and rescue opioids. The primary outcome was percentage of subjects experiencing moderate to severe pain (visual analogue scale >30 mm) upon ambulation at 24 h. Secondary outcomes included pain scores, postoperative inflammation (C-reactive protein), opioid and antiemetics use, and 'Quality of Recovery-15' and 'Opioid-Related Symptom Distress Scale', length of stay, readmissions, and complications up to Day 90. RESULTS: A total of 157 subjects (80 vs 77) were included. No difference was found between groups in the incidence of subjects experiencing visual analogue scale >30 on ambulation 24 h after surgery (56% vs 53%, relative risk =1.07, confidence interval: 0.8-1.4, P=0.65). No differences in other pain outcomes or use of rescue opioids and antiemetics, in Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, length of stay, readmissions, or complications. C-reactive protein values were comparable at 24 h (13 [6-25] mg L-1vs 16 [9-38] mg L-1, P = 0.07), but lower at 48 h (26 [9-52] mg L-1vs 50 [30-72] mg L-1, P<0.01) in the high-dose group. CONCLUSION: Use of 1 mg kg-1vs 0.3 mg kg-1 i.v. dexamethasone in low pain responders after TKA did not improve early postoperative pain or other outcomes in contrast to benefits in a high pain responder population. CLINICAL TRIAL REGISTRATION: NCT03758170 (first registration 29-11-2018).

Orthostatic intolerance after fast-track knee arthroplasty: Incidence and hemodynamic pathophysiology.

BACKGROUND: Early postoperative mobilization can be hindered by orthostatic intolerance (OI) due to failed orthostatic cardiovascular regulation. The underlying mechanisms are not fully understood and specific data after total knee arthroplasty (TKA) are lacking. Therefore, we evaluated the incidence of OI and the cardiovascular response to mobilization in fast-track TKA. METHODS: This prospective observational cohort study included 45 patients scheduled for primary TKA in spinal anesthesia with a multimodal opioid-sparing analgesic regime. OI and the cardiovascular response to sitting and standing were evaluated with a standardized mobilization procedure preoperatively, and at 6 and 24 h postoperatively. Hemodynamic variables were measured non-invasively (LiDCO™ Rapid). Perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, opioid use, and pain during mobilization were recorded. RESULTS: Eighteen (44%) and 8 (22%) patients demonstrated OI at 6 and 24 h after surgery, respectively. Four (10%) and 2 (5%) patients experienced severe OI and terminated the mobilization procedure prematurely. Dizziness was the most common OI symptom during mobilization at 6 h. OI was associated with decreased orthostatic responses in systolic, diastolic, mean arterial pressures, and heart rate (all p < .05), while severe OI patients demonstrated impaired diastolic, mean arterial pressures, heart rate, and cardiac output responses (all p < .05). No statistically significant differences in perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, pain, or opioid use were observed between orthostatic tolerant and intolerant patients. CONCLUSION: Early postoperative OI is common following fast-track TKA. Pathophysiologic mechanisms include impaired orthostatic cardiovascular responses. The progression to severe OI symptoms appears to be primarily due to inadequate heart rate response.

The effect of vasoconstriction on intestinal perfusion is determined by preload dependency: A prospective observational study.

BACKGROUND: The effects of vasoconstriction on cardiac stroke volume (SV) and indices of peripheral and intestinal perfusion are insufficiently described. METHODS: In a non-randomized clinical study, 30 patients undergoing elective rectal surgery were exposed to modulation of preload. The primary endpoint was intestinal perfusion (flux), measured by single-point laser Doppler flowmetry. Secondary endpoints were central cardiovascular variables obtained by the LiDCO rapid monitor, the peripheral perfusion index (PPI) derived from the pulse oximetry signal and muscle (StO2 ) and cerebral oxygenation (ScO2 ) determined by near-infrared spectroscopy. RESULTS: For the whole cohort (n = 30), administration of Phenylephrine during HUT induced a median [IQR] increase in SV by 22% [14-41], p = .003 and in mean arterial pressure (MAP) by 54% [31-62], p < .001, with no change in PPI, StO2 and ScO2 or flux. In patients who were preload dependent during HUT (stroke volume variation; SSV >10%; n = 23), administration of phenylephrine increased SV by 29% [12-43], p = .01 and MAP by 54% [33-63], p < .001, followed by an increase in intestinal perfusion flux by 60% [15-289], p = .05, while PPI, StO2 and ScO2  remained unchanged. For non-preload dependent patients (SSV <10%; n = 7), no changes in hemodynamic indices were seen besides an increase in MAP by 54% [33-58], p = .002. CONCLUSION: The reflection of vasoconstrictive modulation of preload in systemic cardiovascular variables and indices of perfusion was dependent on preload responsiveness. Administration of phenylephrine to increase preload did not appear to compromise organ perfusion.

High-dose steroids in high pain responders undergoing total knee arthroplasty: a randomised double-blind trial.

BACKGROUND: Total knee arthroplasty (TKA) is associated with moderate-to-severe postoperative pain despite multimodal opioid-sparing analgesia. Pain catastrophising or preoperative opioid therapy is associated with increased postoperative pain. Preoperative glucocorticoid improves pain after TKA, but dose-finding studies and benefit in high pain responders are lacking. METHODS: A randomised double-blind controlled trial with preoperative high-dose intravenous dexamethasone 1 mg kg-1 or intermediate-dose dexamethasone 0.3 mg kg-1 in 88 patients undergoing TKA with preoperative pain catastrophising score >20 or regular opioid use was designed. The primary outcome was the proportion of patients experiencing moderate-to-severe pain (VAS >30) during a 5 m walk 24 h postoperatively. Secondary outcomes included pain at rest during nights and at passive leg raise, C-reactive protein, opioid use, quality of sleep, Quality of Recovery-15 and Opioid-Related Symptom Distress Scale, readmission, and complications. RESULTS: Moderate-to-severe pain when walking 24 h postoperatively was reduced (high dose vs intermediate dose, 49% vs 79%; P<0.01), along with pain at leg raise at 24 and 48 h (14% vs 29%, P=0.02 and 12% vs 31%, P=0.03, respectively). C-reactive protein was reduced in the high-dose group at both 24 and 48 h (both P<0.01). Quality of Recovery-15 was also improved (P<0.01). CONCLUSIONS: When compared with preoperative dexamethasone 0.3 mg kg-1 i.v., dexamethasone 1 mg kg-1 reduced moderate-to-severe pain 24 h after TKA and improved recovery in high pain responders without apparent side-effects. CLINICAL TRIAL REGISTRATION: NCT03763734.

Association of the intraoperative peripheral perfusion index with postoperative morbidity and mortality in acute surgical patients: a retrospective observational multicentre cohort study.

BACKGROUND: We hypothesised that in acute high-risk surgical patients, a lower intraoperative peripheral perfusion index (PPI) would indicate a higher risk of postoperative complications and mortality. METHODS: This retrospective observational study included 1338 acute high-risk surgical patients from November 2017 until October 2018 at two University Hospitals in Denmark. Intraoperative PPI was the primary exposure variable and the primary outcome was severe postoperative complications defined as a Clavien-Dindo Class ≥III or death, within 30 days. RESULTS: intraoperative PPI was associated with severe postoperative complications or death: odds ratio (OR) 1.12 (95% confidence interval [CI] 1.05-1.19; P<0.001), with an association of intraoperative mean PPI ≤0.5 and PPI ≤1.5 with the primary outcome: OR 1.79 (95% CI 1.09-2.91; P=0.02) and OR 1.65 (95% CI 1.20-2.27; P=0.002), respectively. Each 15-min increase in intraoperative time spend with low PPI was associated with the primary outcome (per 15 min with PPI ≤0.5: OR 1.11 (95% CI 1.05-1.17; P<0.001) and with PPI ≤1.5: OR 1.06 (95% CI 1.02-1.09; P=0.002)). Thirty-day mortality in patients with PPI ≤0.5 was 19% vs 10% for PPI >0.5, P=0.003. If PPI was ≤1.5, 30-day mortality was 16% vs 8% in patients with a PPI >1.5 (P<0.001). In contrast, intraoperative mean MAP ≤65 mm Hg was not significantly associated with severe postoperative complications or death (OR 1.21 [95% CI 0.92-1.58; P=0.2]). CONCLUSIONS: Low intraoperative PPI was associated with severe postoperative complications or death in acute high-risk surgical patients. To guide intraoperative haemodynamic management, the PPI should be further investigated.

Inflammatory response, fluid balance and outcome in emergency high-risk abdominal surgery.

BACKGROUND: The main disease etiologies requiring emergency high-risk abdominal surgery are intestinal obstruction and perforated viscus and the differences in immune response to these pathologies are largely unexplored. In search of improvement of patient assessment in the perioperative phase, we examined the inflammatory response in this setting, focusing on potential difference in pathophysiology. METHODS: The electronic medical records of 487 patients who underwent emergency abdominal surgery from year 2013-2015 for intestinal obstruction and perforated viscus were reviewed. We evaluated the relationship between pre- and postoperative C-reactive protein (CRP) trajectory, fluid balance, and perioperative morbidity and mortality according to type of surgery, intervention, and surgical pathology. RESULTS: A total of 418 patients were included. Pre- and postoperative absolute CRP values were significantly higher in patients with perforated viscus (n = 203) than in intestinal obstruction (n = 215) (P < .0001). Relative changes at hour 6 and POD 1 were non-significant (P = .716 and P = .816 respectively). There was significant association between both pre- (quartile 1 vs 4, OR 5.11; P < .01) and postoperative (quartile 1 vs 4, OR 4.10; P < .001) CRP and adverse outcome, along with fluid balance and adverse outcome in patients with obstruction but not in those with perforation. Fluid balance and CRP had statistically significant positive correlation in patients with obstruction. CONCLUSIONS: In this explorative study, a high pre- and postoperative CRP and a high positive fluid balance were associated with worse outcome in patients with intestinal obstruction, but not in patients with perforated viscus. Future studies should address the different inflammatory and fluid trajectories in these specific pathologies.

Peripheral nerve block anaesthesia and postoperative pain in acute ankle fracture surgery: the AnAnkle randomised trial.

BACKGROUND: Peripheral nerve blocks (PNBs) are increasingly popular in acute ankle fracture surgery but rebound pain may outweigh the benefits. The AnAnkle Trial was designed to assess the postoperative pain profile of PNB anaesthesia compared with spinal anaesthesia (SA). METHODS: The AnAnkle Trial was a randomised, two-centre, blinded outcome analysis trial. Eligible adults booked for primary ankle fracture surgery were randomised to PNB or SA. The PNBs were ultrasound-guided popliteal sciatic and saphenous blocks with ropivacaine and SAs were with hyperbaric bupivacaine. Postoperatively, all subjects received paracetamol, ibuprofen, and patient-controlled i.v. morphine for pain. The primary endpoint was 27 h Pain Intensity and Opioid Consumption (PIOC) score. Secondary endpoints included longitudinal pain scores and morphine consumption separately, and questionnaires on quality of recovery. RESULTS: This study enrolled 150 subjects, and the PNB success rate was >94%. PIOC was lower with PNB anaesthesia (median, -26.5% vs +54.3%; P<0.001) and the probability of a better PIOC score with PNB than with SA was 74.8% (95% confidence interval, 67.0-82.6). Pain scores and morphine consumption analysed separately also yielded a clear benefit with PNB, despite substantial rebound pain when PNBs subsided. Quality of recovery scores were similar between groups, but 99% having PNB vs 90% having SA would choose the same anaesthesia form again (P=0.03). CONCLUSIONS: PNB anaesthesia was efficient and provided a superior postoperative pain profile compared with SA for acute ankle fracture surgery, despite potentially intense rebound pain after PNB. CLINICAL TRIAL REGISTRATION: Clinicaltrialsregister.eu, EudraCT number: 2015-001108-76.

Population pharmacokinetics of ropivacaine used for local infiltration anaesthesia during primary total unilateral and simultaneous bilateral knee arthroplasty.

BACKGROUND: Ropivacaine is commonly used in local infiltration anaesthesia (LIA) as pain management after total knee arthroplasty (TKA). Although considered safe, no studies evaluated the pharmacokinetics of high-dose ropivacaine infiltration in simultaneous bilateral TKA. METHODS: We studied 13 patients undergoing unilateral and 15 undergoing bilateral TKA. Standard LIA technique was used with ropivacaine 0.2%, 200 ml (400 mg) injected peri-articularly in each knee. Free and total plasma concentrations of ropivacaine were measured within 24 h using liquid chromatography-mass spectrometry. A population pharmacokinetic model was built using non-linear mixed-effects models. RESULTS: Peak free ropivacaine concentration was 0.030 (0.017-0.071) µg ml-1 (mean [99% confidence interval]) vs 0.095 (0.047-0.208) µg ml-1, and peak total ropivacaine concentration was 0.756 (0.065-1.222) µg ml-1vs 1.695 (0.077-3.005) µg ml-1 for unilateral and bilateral TKA, respectively. The pharmacokinetics was ascribed a one-compartment model with first-order absorption. The main identified covariates were protein binding, allometrically scaled body weight on clearance and volume, and unilateral or bilateral surgery on volume. CONCLUSIONS: This is the first study to investigate the pharmacokinetics of free and total ropivacaine after unilateral and bilateral TKA. A population model was successfully built and peak free ropivacaine concentration stayed below previously proposed toxic thresholds in patients undergoing unilateral and bilateral TKA receiving LIA with high-dose ropivacaine. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04702282.