Myxedema in Both Hyperthyroidism and Hypothyroidism: A Hormetic Response?

Myxedema is a potentially life-threatening condition typically observed in severe hypothyroidism. However, localized or diffuse myxedema is also observed in hyperthyroidism. The exact cause and mechanism of this paradoxical situation is not clear. We report here the analysis of body fluid distribution by bioelectrical impedance analysis (BIA) in 103 thyroid patients, subdivided according to their functional status. All BIA parameters measured in subclinical thyroid dysfunctions did not significantly differ from those observed in euthyroid controls. On the contrary, they were clearly altered in the two extreme, opposite conditions of thyroid dysfunctions, namely overt hyperthyroidism and severe hypothyroidism, indicating the occurrence of a typical hormetic condition. Surprisingly, differences in BIA parameters related to fluid body composition were even more evident in hyperthyroidism than in hypothyroidism. A hormetic response to thyroid hormone (TH)s was previously reported to explain the paradoxical, biphasic, time- and dose-dependent effects on other conditions. Our results indicate that myxedema, observed in both hypothyroid and hyperthyroid conditions, represents another example of a hormetic-type response to THs. BIA offers no additional valuable information in evaluating fluid body composition in subclinical thyroid dysfunctions, but it represents a valuable method to analyze and monitor body fluid composition and distribution in overt and severe thyroid dysfunctions.

Opioid Use and Gut Dysbiosis in Cancer Pain Patients.

Opioids are commonly used for the management of severe chronic cancer pain. Their well-known pharmacological effects on the gastrointestinal system, particularly opioid-induced constipation (OIC), are the most common limiting factors in the optimization of analgesia, and have led to the wide use of laxatives and/or peripherally acting mu-opioid receptor antagonists (PAMORAs). A growing interest has been recently recorded in the possible effects of opioid treatment on the gut microbiota. Preclinical and clinical data, as presented in this review, showed that alterations of the gut microbiota play a role in modulating opioid-mediated analgesia and tolerability, including constipation. Moreover, due to the bidirectional crosstalk between gut bacteria and the central nervous system, gut dysbiosis may be crucial in modulating opioid reward and addictive behavior. The microbiota may also modulate pain regulation and tolerance, by activating microglial cells and inducing the release of inflammatory cytokines and chemokines, which sustain neuroinflammation. In the subset of cancer patients, the clinical meaning of opioid-induced gut dysbiosis, particularly its possible interference with the efficacy of chemotherapy and immunotherapy, is still unclear. Gut dysbiosis could be a new target for treatment in cancer patients. Restoring the physiological amount of specific gut bacteria may represent a promising therapeutic option for managing gastrointestinal symptoms and optimizing analgesia for cancer patients using opioids.

Preoperative SARS-CoV-2 Infection Screening before Thoracic Surgery during COVID-19 Pandemic: A Multicenter Retrospective Study.

Objectives: During coronavirus disease (COVID-19) pandemic, preoperative screening before thoracic surgery is paramount in order to protect patients and staff from undetected infections. This study aimed to determine which preoperative COVID-19 screening tool was the most effective strategy before thoracic surgery. Methods: This retrospective cohort multicenter study was performed at 3 Italian thoracic surgery centers. All adult patients scheduled for thoracic surgery procedures from 4th March until 24th April, 2020, and submitted to COVID-19 preoperative screenings were included. The primary outcome was the yield of screening of the different strategies. Results: A total of 430 screenings were performed on 275 patients; 275 anamnestic questionnaires were administered. 77 patients were screened by an anamnestic questionnaire and reverse transcriptase polymerase chain reaction (RT-PCR). 78 patients were selected to combine screening with anamnestic questionnaire and chest computed tomography (CT). The positive yield of screening using a combination of anamnestic questionnaire and RT-PCR was 7.8% (95% CI: 2.6-14.3), while using a combination of anamnestic questionnaire and chest CT was 3.8% (95% CI: 0-9). Individual yields were 1.1% (95% CI: 0-2.5) for anamnestic questionnaire, 5.2% (95% CI: 1.3-11.7) for RT-PCR, and 3.8% (95% CI: 0-9). Conclusions: The association of anamnestic questionnaire and RT-PCR is able to detect around 8 positives in 100 asymptomatic patients. This combined strategy could be a valuable preoperative SARS-CoV-2 screening tool before thoracic surgery.

A Closer Look at Opioid-Induced Adrenal Insufficiency: A Narrative Review.

Among several opioid-associated endocrinopathies, opioid-associated adrenal insufficiency (OIAI) is both common and not well understood by most clinicians, particularly those outside of endocrine specialization. OIAI is secondary to long-term opioid use and differs from primary adrenal insufficiency. Beyond chronic opioid use, risk factors for OIAI are not well known. OIAI can be diagnosed by a variety of tests, such as the morning cortisol test, but cutoff values are not well established and it is estimated that only about 10% of patients with OIAI will ever be properly diagnosed. This may be dangerous, as OIAI can lead to a potentially life-threatening adrenal crisis. OIAI can be treated and for patients who must continue opioid therapy, it can be clinically managed. OIAI resolves with opioid cessation. Better guidance for diagnosis and treatment is urgently needed, particularly in light of the fact that 5% of the United States population has a prescription for chronic opioid therapy.

Bilateral Ultrasound-Guided Erector Spinae Plane Block for Pectus Excavatum Surgery: A Retrospective Propensity-Score Study.

OBJECTIVE: Pectus excavatum (PE) repair is burdened by severe postoperative pain. This retrospective study aimed to determine whether the analgesic effect of ultrasound-guided erector spinae plane block (ESPB) plus standard intravenous analgesia (SIVA) might be superior to SIVA alone in pain control after PE surgical repair via Ravitch or Nuss technique. DESIGN: A retrospective cohort study. SETTING: At a university hospital. PARTICIPANTS: All participants were scheduled for surgical repair of PE. INTERVENTIONS: From January 2017 to December 2019, all patients who received ESPB plus SIVA or SIVA alone were investigated retrospectively. A 2:1 propensity-score matching analysis considering preoperative variables was used to compare analgesia efficacy in 2 groups. All patients received a 24-hour continuous infusion of tramadol, 0.1 mg/kg/h, and ketorolac, 0.05 mg/kg/h, via elastomeric pump, and morphine, 2 mg, intravenously as a rescue drug. The ESPB group received preoperative bilateral ESPB block. Postoperative pain, reported using a numerical rating scale at 1, 12, 24, and 48 hours after surgery; the number of required rescue doses; total postoperative morphine milligram equivalents consumption; and the incidence of postoperative nausea and vomit were analyzed. MEASUREMENT AND MAIN RESULTS: A total of 105 patients were identified for analysis. Propensity-score matching resulted in 38 patients in the SIVA group and 19 patients in the ESPB group. Postoperative pain, the number of rescue doses, and postoperative nausea and vomit incidences were lower in the ESPB group (p < 0.005). CONCLUSIONS: Erector spinae plane block may be an effective option for pain management after surgical repair of PE as part of a multimodal approach. This study showed good perioperative analgesia, opioid sparing, and reduced opioid-related adverse effects.

The Impact of P-Glycoprotein on Opioid Analgesics: What's the Real Meaning in Pain Management and Palliative Care?

Opioids are widely used in cancer and non-cancer pain management. However, many transporters at the blood-brain barrier (BBB), such as P-glycoprotein (P-gp, ABCB1/MDR1), may impair their delivery to the brain, thus leading to opioid tolerance. Nonetheless, opioids may regulate P-gp expression, thus altering the transport of other compounds, namely chemotherapeutic agents, resulting in pharmacoresistance. Other kinds of painkillers (e.g., acetaminophen, dexamethasone) and adjuvant drugs used for neuropathic pain may act as P-gp substrates and modulate its expression, thus making pain management challenging. Inflammatory conditions are also believed to upregulate P-gp. The role of P-gp in drug-drug interactions is currently under investigation, since many P-gp substrates may also act as substrates for the cytochrome P450 enzymes, which metabolize a wide range of xenobiotics and endobiotics. Genetic variability of the ABCB1/MDR1 gene may be accountable for inter-individual variation in opioid-induced analgesia. P-gp also plays a role in the management of opioid-induced adverse effects, such as constipation. Peripherally acting mu-opioid receptors antagonists (PAMORAs), such as naloxegol and naldemedine, are substrates of P-gp, which prevent their penetration in the central nervous system. In our review, we explore the interactions between P-gp and opioidergic drugs, with their implications in clinical practice.

The Normobaric Oxygen Paradox-Hyperoxic Hypoxic Paradox: A Novel Expedient Strategy in Hematopoiesis Clinical Issues.

Hypoxia, even at non-lethal levels, is one of the most stressful events for all aerobic organisms as it significantly affects a wide spectrum of physiological functions and energy production. Aerobic organisms activate countless molecular responses directed to respond at cellular, tissue, organ, and whole-body levels to cope with oxygen shortage allowing survival, including enhanced neo-angiogenesis and systemic oxygen delivery. The benefits of hypoxia may be evoked without its detrimental consequences by exploiting the so-called normobaric oxygen paradox. The intermittent shift between hyperoxic-normoxic exposure, in addition to being safe and feasible, has been shown to enhance erythropoietin production and raise hemoglobin levels with numerous different potential applications in many fields of therapy as a new strategy for surgical preconditioning aimed at frail patients and prevention of postoperative anemia. This narrative review summarizes the physiological processes behind the proposed normobaric oxygen paradox, focusing on the latest scientific evidence and the potential applications for this strategy. Future possibilities for hyperoxic-normoxic exposure therapy include implementation as a synergistic strategy to improve a patient's pre-surgical condition, a stimulating treatment in critically ill patients, preconditioning of athletes during physical preparation, and, in combination with surgery and conventional chemotherapy, to improve patients' outcomes and quality of life.

Nonthyroidal illness syndrome (NTIS) in severe COVID-19 patients: role of T3 on the Na/K pump gene expression and on hydroelectrolytic equilibrium.

BACKGROUND: Nonthyroidal Illness Syndrome (NTIS) can be detected in many critical illnesses. Recently, we demonstrated that this condition is frequently observed in COVID-19 patients too and it is correlated with the severity the disease. However, the exact mechanism through which thyroid hormones influence the course of COVID-19, as well as that of many other critical illnesses, is not clear yet and treatment with T4, T3 or a combination of both is still controversial. Aim of this study was to analyze body composition in COVID-19 patients in search of possible correlation with the thyroid function. METHODS AND FINDINGS: We report here our experience performed in 74 critically ill COVID-19 patients hospitalized in the intensive care unit (ICU) of our University Hospital in Rome. In these patients, we evaluated the thyroid hormone function and body composition by Bioelectrical Impedance Analysis (BIA) during the acute phase of the disease at admission in the ICU. To examine the effects of thyroid function on BIA parameters we analyzed also 96 outpatients, affected by thyroid diseases in different functional conditions. We demonstrated that COVID-19 patients with low FT3 serum values exhibited increased values of the Total Body Water/Free Fat Mass (TBW/FFM) ratio. Patients with the lowest FT3 serum values had also the highest level of TBW/FFM ratio. This ratio is an indicator of the fraction of FFM as water and represents one of the best-known body-composition constants in mammals. We found an inverse correlation between FT3 serum values and this constant. Reduced FT3 serum values in COVID-19 patients were correlated with the increase in the total body water (TBW), the extracellular water (ECW) and the sodium/potassium exchangeable ratio (Nae:Ke), and with the reduction of the intracellular water (ICW). No specific correlation was observed in thyroid patients at different functional conditions between any BIA parameters and FT3 serum values, except for the patient with myxedema, that showed a picture similar to that seen in COVID-19 patients with NTIS. Since the Na+/K+ pump is a well-known T3 target, we measured the mRNA expression levels of the two genes coding for the two major isoforms of this pump. We demonstrated that COVID-19 patients with NTIS had lower levels of mRNA of both genes in the peripheral blood mononuclear cells (PBMC)s obtained from our patients during the acute phase of the disease. In addition, we retrieved data from transcriptome analysis, performed on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM)s treated with T3 and we demonstrated that in these cells T3 is able to stimulate the expression of these two genes in a dose-dependent manner. CONCLUSIONS: In conclusion, we demonstrated that measurement of BIA parameters is a useful method to analyze water and salt retention in COVID-19 patients hospitalized in ICU and, in particular, in those that develop NTIS. Our results indicate that NTIS has peculiar similarities with myxedema seen in severe hypothyroid patients, albeit it occurs more rapidly. The Na+/K+ pump is a possible target of T3 action, involved in the pathogenesis of the anasarcatic condition observed in our COVID-19 patients with NTIS. Finally, measurement of BIA parameters may represent good endpoints to evaluate the benefit of future clinical interventional trials, based on the administration of T3 in patients with NTIS.

The role of teicoplanin in the treatment of SARS-CoV-2 infection: A retrospective study in critically ill COVID-19 patients (Tei-COVID study).

Teicoplanin has a potential antiviral activity expressed against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was suggested as a complementary option to treat coronavirus disease 2019 (COVID-19) patients. In this multicentric, retrospective, observational research the aim was to evaluate the impact of teicoplanin on the course of COVID-19 in critically ill patients. Fifty-five patients with severe COVID-19, hospitalized in the intensive care units (ICUs) and treated with best available therapy were retrospectively analysed. Among them 34 patients were also treated with teicoplanin (Tei-COVID group), while 21 without teicoplanin (control group). Crude in-hospital Day-30 mortality was lower in Tei-COVID group (35.2%) than in control group (42.8%), however not reaching statistical significance (p = .654). No statistically significant differences in length of stay in the ICU were observed between Tei-COVID group and control group (p = .248). On Day 14 from the ICU hospitalization, viral clearance was achieved in 64.7% patients of Tei-COVID group and 57.1% of control group, without statistical difference. Serum C-reactive protein level was significantly reduced in Tei-COVID group compared to control group, but not other biochemical parameters. Finally, Gram-positive were the causative pathogens for 25% of BSIs in Tei-COVID group and for 70.6% in controls. No side effects related to teicoplanin use were observed. Despite several limitations require further research, in this study the use of teicoplanin is not associated with a significant improvement in outcomes analysed. The antiviral activity of teicoplanin against SARS-CoV-2, previously documented, is probably more effective at early clinical stages.

Antibiotic Prophylaxis for Percutaneous Endoscopic Gastrostomy in Children: A Randomised Controlled Trial.

OBJECTIVES: Paediatric studies on the role of antibiotic prophylaxis in the prevention of postoperative infections in children undergoing percutaneous endoscopic gastrostomy (PEG) are lacking. The aim of this study was to assess if a single dose of co-amoxiclav before PEG can decrease the rate of peristomal wound and systemic infection in children. METHODS: In this prospective, randomised, double-blind, multicentre trial, children undergoing PEG were randomized to antibiotic prophylaxis with co-amoxiclav versus placebo and the rate of local and systemic infections were assessed. RESULTS: Of the 106 patients considered for inclusion, 49 patients were randomized. In the per-protocol analysis, the occurrence of wound infection was 5% (1/20) in the antibiotic group and 21% (4/19) in the placebo group (P = 0.13, 16% difference in proportions, odds ratio [OR] 0.19, 95% confidence interval [CI] 0.02-1.9). The occurrence of systemic infection was 9% (2/22) in the antibiotic group and 27.2% (6/25) in the placebo group [P = 0.17, 18% difference in proportions, OR 0.32, 95% CI 0.06%-1.80%]. Similar results were obtained in intention-to-treat analysis. Interestingly, the overall infection rate was significantly higher in the placebo group as compared with the antibiotic group (40% vs 13.6%; P = 0.04) and the duration of hospital stay was significantly longer in the placebo group as compared with the antibiotic group (4.4 ±â€Š1.6 vs 3.5 ±â€Š1.05; P = 0.02). The number-needed-to-treat (NTT) to prevent 1 peristomal infection on average are 6.7 patients. CONCLUSIONS: A preoperative dose of co-amoxiclav reduces the overall infection rate and the duration of hospital stay. Our data suggest that antibiotic prophylaxis should be recommended in every children undergoing PEG placement.

Cardiometabolic multimorbidity is associated with a worse Covid-19 prognosis than individual cardiometabolic risk factors: a multicentre retrospective study (CoViDiab II).

BACKGROUND: Cardiometabolic disorders may worsen Covid-19 outcomes. We investigated features and Covid-19 outcomes for patients with or without diabetes, and with or without cardiometabolic multimorbidity. METHODS: We collected and compared data retrospectively from patients hospitalized for Covid-19 with and without diabetes, and with and without cardiometabolic multimorbidity (defined as ≥ two of three risk factors of diabetes, hypertension or dyslipidaemia). Multivariate logistic regression was used to assess the risk of the primary composite outcome (any of mechanical ventilation, admission to an intensive care unit [ICU] or death) in patients with diabetes and in those with cardiometabolic multimorbidity, adjusting for confounders. RESULTS: Of 354 patients enrolled, those with diabetes (n = 81), compared with those without diabetes (n = 273), had characteristics associated with the primary composite outcome that included older age, higher prevalence of hypertension and chronic obstructive pulmonary disease (COPD), higher levels of inflammatory markers and a lower PaO2/FIO2 ratio. The risk of the primary composite outcome in the 277 patients who completed the study as of May 15th, 2020, was higher in those with diabetes (Adjusted Odds Ratio (adjOR) 2.04, 95%CI 1.12-3.73, p = 0.020), hypertension (adjOR 2.31, 95%CI: 1.37-3.92, p = 0.002) and COPD (adjOR 2.67, 95%CI 1.23-5.80, p = 0.013). Patients with cardiometabolic multimorbidity were at higher risk compared to patients with no cardiometabolic conditions (adjOR 3.19 95%CI 1.61-6.34, p = 0.001). The risk for patients with a single cardiometabolic risk factor did not differ with that for patients with no cardiometabolic risk factors (adjOR 1.66, 0.90-3.06, adjp = 0.10). CONCLUSIONS: Patients with diabetes hospitalized for Covid-19 present with high-risk features. They are at increased risk of adverse outcomes, likely because diabetes clusters with other cardiometabolic conditions.

Potential markers of healing from near infrared spectroscopy imaging of venous leg ulcer. A randomized controlled clinical trial comparing conventional with hyperbaric oxygen treatment.

The aim of this study is to ascertain whether the simultaneous measurement of hemoglobin O2 saturation (StO2 ) and dimension of venous leg ulcers (VLU) by near infrared spectroscopy (NIRS) imaging can predict the healing course with protocols employing a conventional treatment alone or in combination with hyperbaric oxygen therapy (HBOT). NIRS 2D images of wound region were obtained in 81 patients with hard-to-heal VLU that had been assigned, in a randomized controlled clinical trial, to the following protocols: 30 HBOT sessions, adjunctive to the conventional therapy, either twice daily over 3 weeks (group A) or once daily over 6 weeks (group B), and conventional therapy without HBOT (group C). Seventy-three patients completed the study with a total of 511 NIRS images being analyzed. At the end of treatment, wound area was significantly smaller in all three groups. However, at the 3-week mark the wound area reduction tended to be less evident in group A than in the other groups. This trend continued up to the 6-week end-point when a significantly greater area reduction was found with group B (65.5%) and group C (56.8%) compared to group A (29.7%) (P < .01). Furthermore, a higher incidence of complete healing was noted with group B (20%) than with group A (4.5%) and group C (3.8%). When using a final wound reduction in excess of 40% to distinguish healing from nonhealing ulcers, it was found that only the former present NIRS StO2 values abating over the study period both at center and edge of lesions. In conclusion, NIRS analysis of StO2 and wound area can predict the healing course of VLU. Adjunctive HBOT significantly facilitates VLU healing compared to the conventional treatment alone. This positive action, however, becomes manifest only with a longer and less intensive treatment schedule.

The Cutting Edge of Thoracic Anesthesia During the Coronavirus Disease 2019 (COVID-19) Outbreak.

Coronavirus disease 2019 (COVID-19) has quickly spread globally, causing a real pandemic. In this critical scenario, lung cancer patients scheduled for surgical treatment need to continue to receive optimal care while protecting them from an eventual severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Adequate use of personal protective equipment (PPE) during aerosol-generating procedures (AGPs) and a COVID-19 specific intraoperative management are paramount in order to prevent cross infections. New suggestions or improvement of existing contagion control guidance are needed, even in case of non-symptomatic patients, possibly responsible for virus spread.

Ultrasound-Guided Erector Spinae Plane Block Versus Intercostal Nerve Block for Post-Minithoracotomy Acute Pain Management: A Randomized Controlled Trial.

OBJECTIVE: Several nerve block procedures are available for post-thoracotomy pain management. DESIGN: In this randomized trial, the authors aimed to determine whether the analgesic effect of preoperative ultrasound-guided erector spinae plane block (ESPB) might be superior to that of intraoperative intercostal nerve block (ICNB) in pain control in patients undergoing minithoracotomy. SETTING: University hospital. PARTICIPANTS: Sixty consecutive adult patients scheduled to undergo minithoracotomy for lung resection were enrolled. INTERVENTIONS: Patients were allocated randomly in a 1:1 ratio to receive either single-shot ESPB or ICNB. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the intensity of postoperative pain at rest, assessed with the numeric rating scale (NRS). The secondary outcomes were (1) dynamic NRS values (during cough); (2) perioperative analgesic requirements; (3) patient satisfaction, on the basis of a verbal scale (Likert scale); and (4) respiratory muscle strength, considering the maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) variation from baseline. The ESPB group showed lower postoperative static and dynamic NRS values than the ICNB group (p < 0.05). Total remifentanil consumption and requirements for additional analgesics were lower in the ESPB group (p < 0.05). Patient satisfaction was higher in the ESPB group (p < 0.001). A significant overall time effect was found in MIP and MEP variation (p < 0.001); ESPB values were higher at all points, reaching a statistically significant level at the first and sixth hours for MIP, and at the first, 12th, 24th, and 48th hours for MEP (p < 0.05). CONCLUSIONS: ESPB was demonstrated to provide superior analgesia, lower perioperative analgesic requirements, better patient satisfaction, and less respiratory muscle strength impairment than ICNB in patients undergoing minithoracotomy.

Correction to: Inert gas narcosis in scuba diving, different gases different reactions.

The original version of this article unfortunately contained a mistake.

Inert gas narcosis in scuba diving, different gases different reactions.

PURPOSE: Underwater divers face several potential neurological hazards when breathing compressed gas mixtures including nitrogen narcosis which can impact diver's safety. Various human studies have clearly demonstrated brain impairment due to nitrogen narcosis in divers at 4 ATA using critical flicker fusion frequency (CFFF) as a cortical performance indicator. However, recently some authors have proposed a probable adaptive phenomenon during repetitive exposure to high nitrogen pressure in rats, where they found a reversal effect on dopamine release. METHODS: Sixty experienced divers breathing Air, Trimix or Heliox, were studied during an open water dive to a depth of 6 ATA with a square profile testing CFFF measurement before (T0), during the dive upon arriving at the bottom (6 ATA) (T1), 20 min of bottom time (T2), and at 5 m (1.5 ATA) (T3). RESULTS: CFFF results showed a slight increase in alertness and arousal during the deep dive regardless of the gas mixture breathed. The percent change in CFFF values at T1 and T2 differed among the three groups being lower in the air group than in the other groups. All CFFF values returned to basal values 5 min before the final ascent at 5 m (T3), but the Trimix measurements were still slightly better than those at T0. CONCLUSIONS: Our results highlight that nitrogen and oxygen alone and in combination can produce neuronal excitability or depression in a dose-related response.

Low-dose buprenorphine infusion to prevent postoperative hyperalgesia in patients undergoing major lung surgery and remifentanil infusion: a double-blind, randomized, active-controlled trial.

BACKGROUND: Postoperative secondary hyperalgesia arises from central sensitization due to pain pathways facilitation and/or acute opioid exposure. The latter is also known as opioid-induced hyperalgesia (OIH). Remifentanil, a potent µ-opioid agonist, reportedly induces postoperative hyperalgesia and increases postoperative pain scores and opioid consumption. The pathophysiology underlying secondary hyperalgesia involves N-methyl-D-aspartate (NMDA)-mediated pain pathways. In this study, we investigated whether perioperatively infusing low-dose buprenorphine, an opioid with anti-NMDA activity, in patients receiving remifentanil infusion prevents postoperative secondary hyperalgesia. METHODS: Sixty-four patients, undergoing remifentanil infusion during general anaesthesia and major lung surgery, were randomly assigned to receive either buprenorphine i.v. infusion (25 µg h-1 for 24 h) or morphine (equianalgesic dose) perioperatively. The presence and extent of punctuate hyperalgesia were assessed one day postoperatively. Secondary outcome variables included postoperative pain scores, opioid consumption and postoperative neuropathic pain assessed one and three months postoperatively. RESULTS: A distinct area of hyperalgesia or allodynia around the surgical incision was found in more patients in the control group than in the treated group. Mean time from extubation to first morphine rescue dose was twice as long in the buprenorphine-treated group than in the morphine-treated group: 18 vs 9 min (P=0.002). At 30 min postoperatively, patients receiving morphine had a higher hazard ratio for the first analgesic rescue dose than those treated with buprenorphine (P=0.009). At three months, no differences between groups were noted. CONCLUSIONS: Low-dose buprenorphine infusion prevents the development of secondary hyperalgesia around the surgical incision but shows no long-term efficacy at three months follow-up.

Bedside Assessment of the Microvascular Venous Compartment in Cardiac Surgery Patients With Valvular Diseases Undergoing Cardiopulmonary Bypass.

OBJECTIVE: Blood volume reserve for venous return and the effects of cardiopulmonary bypass (CPB) on microvascular bed partitioning and blood flow were examined in patients with valvular diseases. DESIGN: Prospective, consecutive, case-control study. SETTING: Single university hospital. PARTICIPANTS: The study comprised 20 adult cardiac surgery patients and 20 healthy volunteers. INTERVENTIONS: Cardiovascular and microvascular variables were collected soon after the induction of anesthesia, after commencement of CPB, 20 minutes after separation from CPB, and in the intensive care unit. MEASUREMENTS AND MAIN RESULTS: The unstressed and stressed volumes (Vu, Vs) and pressures therein (Pit, Ps) were measured in the brachioradial muscle with near-infrared spectroscopy, applying incremental venous occlusions. At the first time point, Vs and Pit showed lower and higher values, respectively, than those of control patients, but Vs increased with Vu during the study, whereas Pit remained unchanged. Fluid balance correlated with Pit (r = 0.83, p<0.001) and hemoglobin (r = 0.78, p = 0.004). A nonlinear regression was found between fluid balance and ΔVu (r = 0.90, p<0.001) [y = 1.85+37.43(-0.01×x)]. The Vu/Pit and Vs/Ps ratios were lower than those of the control patients. Blood flow correlated to Vs/Ps (r = 0.75, p<0.001). The time constant was lower than reference (p = 0.005) and increased 10 times after CPB. CONCLUSIONS: Cardiac surgery patients have a limited blood volume reserve for venous return due to a reduced microvascular bed capacitance. This study demonstrated that during CPB a positive fluid balance induced an extravascular pressure increase and further reduced blood volume reserve.