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.

A semi-automated device rapidly determine circulating blood volume in healthy males and carbon monoxide uptake kinetics of arterial and venous blood.

We examined whether a semi-automated carbon monoxide (CO) rebreathing method accurately detect changes in blood volume (BV) and total hemoglobin mass (tHb). Furthermore, we investigated whether a supine position with legs raised reduced systemic CO dilution time, potentially allowing a shorter rebreathing period. Nineteen young healthy males participated. BV and tHb was quantified by a 10-min CO-rebreathing period in a supine position with legs raised before and immediately after a 900 ml phlebotomy and before and after a 900 ml autologous blood reinfusion on the same day in 16 subjects. During the first CO-rebreathing, arterial and venous blood samples were drawn every 2 min during the procedure to determine systemic CO equilibrium in all subjects. Phlebotomy decreased (P < 0.001) tHb and BV by 166 ± 24 g and 931 ± 247 ml, respectively, while reinfusion increased (P < 0.001) tHb and BV by 143 ± 21 g and 862 ± 250 ml compared to before reinfusion. After reinfusion BV did not differ from baseline levels while tHb was decreased (P < 0.001) by 36 ± 21 g. Complete CO mixing was achieved within 6 min in venous and arterial blood, respectively, when compared to the 10-min sample. On an individual level, the relative accuracy after donation for tHb and BV was 102-169% and 55-165%, respectively. The applied CO-rebreathing procedure precisely detect acute BV changes with a clinically insignificant margin of error. The 10-min CO-procedure may be reduced to 6 min with no clinical effects on BV and tHb calculation. Notwithstanding, individual differences may be of concern and should be investigated further.

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.

Efficacy and safety of sugammadex versus neostigmine in reversing neuromuscular blockade in adults.

BACKGROUND: Acetylcholinesterase inhibitors, such as neostigmine, have traditionally been used for reversal of non-depolarizing neuromuscular blocking agents. However, these drugs have significant limitations, such as indirect mechanisms of reversal, limited and unpredictable efficacy, and undesirable autonomic responses. Sugammadex is a selective relaxant-binding agent specifically developed for rapid reversal of non-depolarizing neuromuscular blockade induced by rocuronium. Its potential clinical benefits include fast and predictable reversal of any degree of block, increased patient safety, reduced incidence of residual block on recovery, and more efficient use of healthcare resources. OBJECTIVES: The main objective of this review was to compare the efficacy and safety of sugammadex versus neostigmine in reversing neuromuscular blockade caused by non-depolarizing neuromuscular agents in adults. SEARCH METHODS: We searched the following databases on 2 May 2016: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (WebSPIRS Ovid SP), Embase (WebSPIRS Ovid SP), and the clinical trials registries www.controlled-trials.com, clinicaltrials.gov, and www.centerwatch.com. We re-ran the search on 10 May 2017. SELECTION CRITERIA: We included randomized controlled trials (RCTs) irrespective of publication status, date of publication, blinding status, outcomes published, or language. We included adults, classified as American Society of Anesthesiologists (ASA) I to IV, who received non-depolarizing neuromuscular blocking agents for an elective in-patient or day-case surgical procedure. We included all trials comparing sugammadex versus neostigmine that reported recovery times or adverse events. We included any dose of sugammadex and neostigmine and any time point of study drug administration. DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts to identify trials for eligibility, examined articles for eligibility, abstracted data, assessed the articles, and excluded obviously irrelevant reports. We resolved disagreements by discussion between review authors and further disagreements through consultation with the last review author. We assessed risk of bias in 10 methodological domains using the Cochrane risk of bias tool and examined risk of random error through trial sequential analysis. We used the principles of the GRADE approach to prepare an overall assessment of the quality of evidence. For our primary outcomes (recovery times to train-of-four ratio (TOFR) > 0.9), we presented data as mean differences (MDs) with 95 % confidence intervals (CIs), and for our secondary outcomes (risk of adverse events and risk of serious adverse events), we calculated risk ratios (RRs) with CIs. MAIN RESULTS: We included 41 studies (4206 participants) in this updated review, 38 of which were new studies. Twelve trials were eligible for meta-analysis of primary outcomes (n = 949), 28 trials were eligible for meta-analysis of secondary outcomes (n = 2298), and 10 trials (n = 1647) were ineligible for meta-analysis.We compared sugammadex 2 mg/kg and neostigmine 0.05 mg/kg for reversal of rocuronium-induced moderate neuromuscular blockade (NMB). Sugammadex 2 mg/kg was 10.22 minutes (6.6 times) faster then neostigmine 0.05 mg/kg (1.96 vs 12.87 minutes) in reversing NMB from the second twitch (T2) to TOFR > 0.9 (MD 10.22 minutes, 95% CI 8.48 to 11.96; I2 = 84%; 10 studies, n = 835; GRADE: moderate quality).We compared sugammadex 4 mg/kg and neostigmine 0.07 mg/kg for reversal of rocuronium-induced deep NMB. Sugammadex 4 mg/kg was 45.78 minutes (16.8 times) faster then neostigmine 0.07 mg/kg (2.9 vs 48.8 minutes) in reversing NMB from post-tetanic count (PTC) 1 to 5 to TOFR > 0.9 (MD 45.78 minutes, 95% CI 39.41 to 52.15; I2 = 0%; two studies, n = 114; GRADE: low quality).For our secondary outcomes, we compared sugammadex, any dose, and neostigmine, any dose, looking at risk of adverse and serious adverse events. We found significantly fewer composite adverse events in the sugammadex group compared with the neostigmine group (RR 0.60, 95% CI 0.49 to 0.74; I2 = 40%; 28 studies, n = 2298; GRADE: moderate quality). Risk of adverse events was 28% in the neostigmine group and 16% in the sugammadex group, resulting in a number needed to treat for an additional beneficial outcome (NNTB) of 8. When looking at specific adverse events, we noted significantly less risk of bradycardia (RR 0.16, 95% CI 0.07 to 0.34; I2= 0%; 11 studies, n = 1218; NNTB 14; GRADE: moderate quality), postoperative nausea and vomiting (PONV) (RR 0.52, 95% CI 0.28 to 0.97; I2 = 0%; six studies, n = 389; NNTB 16; GRADE: low quality) and overall signs of postoperative residual paralysis (RR 0.40, 95% CI 0.28 to 0.57; I2 = 0%; 15 studies, n = 1474; NNTB 13; GRADE: moderate quality) in the sugammadex group when compared with the neostigmine group. Finally, we found no significant differences between sugammadex and neostigmine regarding risk of serious adverse events (RR 0.54, 95% CI 0.13 to 2.25; I2= 0%; 10 studies, n = 959; GRADE: low quality).Application of trial sequential analysis (TSA) indicates superiority of sugammadex for outcomes such as recovery time from T2 to TOFR > 0.9, adverse events, and overall signs of postoperative residual paralysis. AUTHORS' CONCLUSIONS: Review results suggest that in comparison with neostigmine, sugammadex can more rapidly reverse rocuronium-induced neuromuscular block regardless of the depth of the block. Sugammadex 2 mg/kg is 10.22 minutes (˜ 6.6 times) faster in reversing moderate neuromuscular blockade (T2) than neostigmine 0.05 mg/kg (GRADE: moderate quality), and sugammadex 4 mg/kg is 45.78 minutes (˜ 16.8 times) faster in reversing deep neuromuscular blockade (PTC 1 to 5) than neostigmine 0.07 mg/kg (GRADE: low quality). With an NNTB of 8 to avoid an adverse event, sugammadex appears to have a better safety profile than neostigmine. Patients receiving sugammadex had 40% fewer adverse events compared with those given neostigmine. Specifically, risks of bradycardia (RR 0.16, NNTB 14; GRADE: moderate quality), PONV (RR 0.52, NNTB 16; GRADE: low quality), and overall signs of postoperative residual paralysis (RR 0.40, NNTB 13; GRADE: moderate quality) were reduced. Both sugammadex and neostigmine were associated with serious adverse events in less than 1% of patients, and data showed no differences in risk of serious adverse events between groups (RR 0.54; GRADE: low quality).

Effect of systematic local infiltration analgesia on postoperative pain in vaginal hysterectomy: a randomized, placebo-controlled trial.

OBJECTIVE: To assess the effect of systematic local infiltration analgesia on postoperative pain in vaginal hysterectomy, and describe the technique in detail. DESIGN: A randomized, double-blind, placebo-controlled study following the CONSORT criteria. SETTING: A university hospital. PATIENTS: Thirty-seven patients undergoing vaginal hysterectomy. METHODS: Patients received high-volume (50 mL) ropivacaine 0.50% (n = 20) or saline (n = 17) infiltration using a systematic technique ensuring uniform delivery to all tissues incised, handled or instrumented during the procedure. MAIN OUTCOME MEASURES: Pain, nausea, vomiting and opioid requirements were assessed for 32 h as well as time spent in the post-anesthesia care unit and time to first mobilization. RESULTS: Pain at rest was significantly reduced after one, four and eight hours in the ropivacaine group (p ≤ 0.001-0.01). Pain during coughing was significantly reduced after one and four hours (p ≤ 0.001 and p ≤ 0.003), and pain during movement was significantly reduced after four hours (p ≤ 0.02). Opioid requirements and time spent in the post-anesthesia care unit were significantly reduced in the ropivacaine group (p < 0.001 and p < 0.001, respectively), as well as the time to first mobilization (p < 0.001). CONCLUSION: Intra-operative systematic local infiltration analgesia reduces postoperative pain in patients undergoing vaginal hysterectomy, facilities mobilization and improves early recovery.

Prostaglandin E2 induces vascular relaxation by E-prostanoid 4 receptor-mediated activation of endothelial nitric oxide synthase.

The present experiments were designed to test the hypothesis that prostaglandin (PG) E(2) causes vasodilatation through activation of endothelial NO synthase (eNOS). Aortic rings from mice with targeted deletion of eNOS and E-prostanoid (EP) receptors were used for contraction studies. Blood pressure changes in response to PGE(2) were measured in conscious mice. Single doses of PGE(2) caused concentration-dependent relaxations during contractions to phenylephrine (EC(50)=5*10(-8) mol/L). Relaxation after PGE(2) was absent in rings without endothelium and in rings from eNOS(-/-) mice and was abolished by N(G)-nitro-l-arginine methyl ester and the soluble guanylate cyclase inhibitor 1H(1,2,4)-oxadiazolo-[4,3-a]quinoxalin-1-one. In PGE(2)-relaxed aortic rings, the cGMP content increased significantly. PGE(2)-induced relaxations were abolished by the EP4 receptor antagonist AE3-208 (10(-8) mol/L) and mimicked by an EP4 agonist (AE1-329, 10(-7) mol/L) in the presence of endothelium and eNOS only. Relaxations were attenuated significantly in rings from EP4(-/-) mice but normal in EP2(-/-). Inhibitors of the cAMP-protein kinase A pathway attenuated, whereas the inhibitor of protein phosphatase 1C, calyculin (10(-8) mol/L), abolished the PGE(2)-mediated relaxation. In aortic rings, PGE(2) dephosphorylated eNOS at Thr(495). Chronically catheterized eNOS(-/-) mice were hypertensive (137+/-3.6 mm Hg, n=13, versus 101+/-3.9 mm Hg, n=9) and exhibited a lower sensitivity of blood pressure reduction in response to PGE(2) compared with wild-type mice. There was no difference in the blood pressure response to nifedipine. These findings show that PGE(2) elicits EP4 receptor-mediated, endothelium-dependent stimulation of eNOS activity by dephosphorylation at Thr(495) resulting in guanylyl cyclase-dependent vasorelaxation and accumulation of cGMP in aortic rings.