Adequate Oxygenation State Maintained during Electroconvulsive Therapy in Nonobese Patients Using the Oxygen Reserve Index: A Pilot Study.

Some controversial reports have observed oxygen desaturation (defined as percutaneous oxygen saturation (SpO2) < 90%) during electroconvulsive therapy (ECT). The purpose of this pilot study was to examine oxygenation states in eight patients during ECT. In addition to the usual hemodynamic monitors and pulse oximeter, the oxygen reserve index (ORi) was monitored using a pulse oximeter. Patients received either no preoxygenation or preoxygenation with 100% oxygen via a tight-fitting mask for 1 or 3 min before induction of anesthesia. ORi increased after preoxygenation. ORi differed significantly between 3 min of preoxygenation and the other two methods before restarting mask ventilation. SpO2 was significantly increased with all methods before stopping manual mask ventilation or before restarting manual mask ventilation compared with that before preoxygenation. No oxygen desaturation was observed at any time with any treatment methods. In nonobese patients, the adequate oxygenation state as shown by SpO2 and ORi was maintained during ECT even without preoxygenation.

Rat model of attention-deficit hyperactivity disorder exhibits delayed recovery from acute incisional pain due to impaired descending noradrenergic inhibition.

Chronic pain and attention-deficit hyperactivity disorder (ADHD) frequently coexist. However, the common pathology is still unclear. Attenuated noradrenergic endogenous analgesia can produce acute pain chronification, and dysfunction of noradrenergic systems in the nervous system is relevant to ADHD symptoms. Noxious stimuli-induced analgesia (NSIA) is measured to estimate noradrenergic endogenous analgesia in spontaneously hypertensive rats (SHR) as an ADHD model and control. Recovery of pain-related behaviors after paw incision was assessed. Contributions of noradrenergic systems were examined by in vivo microdialysis and immunohistochemistry. The SHR showed attenuated NSIA and needed a more extended period for recovery from acute pain. These results suggest ADHD patients exhibit acute pain chronification due to pre-existing attenuated noradrenergic endogenous analgesia. Immunohistochemistry suggests abnormal noradrenaline turnover and downregulation of the target receptor (alpha2a adrenoceptor). Standard ADHD treatment with atomoxetine restored NSIA and shortened the duration of hypersensitivity after the surgery in the SHR. NSIA protocol activated the locus coeruleus, the origin of spinal noradrenaline, of both strains, but only the control exhibited an increase in spinal noradrenaline. This result suggests dysfunction in the noradrenaline-releasing process and can be recognized as a novel mechanism of attenuation of noradrenergic endogenous analgesia.

Randomized active-controlled study of a single preoperative administration of duloxetine to treat postoperative pain and numbness after posterior lumbar interbody fusion surgery.

BACKGROUND: This prospective, randomized, double-blinded, active controlled trial assessed whether a single preoperative administration of 40 mg of duloxetine could decrease postoperative pain and numbness after posterior lumbar interbody fusion surgery (PLIF). METHODS: Patients with an American Society of Anesthesiologists physical status I or II undergoing PLIF were included. At 2 hours before inducing anesthesia, patients were administered 40 mg duloxetine or 4 mg diazepam (control drug). Postoperative pain and other symptoms were evaluated on the basis of a visual analog scale, amount of fentanyl used, fentanyl dose request times, rate of use of adjunctive analgesics (diclofenac sodium or pentazocine), and lower limb numbness score (0-3) during the first 2 postoperative days. RESULTS: Forty-six patients were randomly assigned to the duloxetine and diazepam groups (n = 23 each); 6 were lost to follow-up, and analysis was performed on data from 22 patients in the duloxetine group and 18 in the diazepam group. No significant differences were detected in the patient background, postoperative visual analog scale score at rest in the lumbar region and lower limbs, fentanyl use, rate of analgesic adjuvant use, or incidence of side effects. The numbness score in the lower limbs, however, was significantly lower in the duloxetine group. CONCLUSION: A single preoperative 40-mg dose of duloxetine did not improve postoperative pain after PLIF, but did improve lower limb numbness. Duloxetine may suppress neuropathic pain-like symptoms after PLIF surgery.

Pseudo-intestinal obstruction after transsphenoidal surgery for craniopharyngioma.

Craniopharyngioma surgery is frequently associated with the occurrence of central diabetes insipidus, and oral rehydration therapy is reliable for postoperative management if the patient's thirst is normal. A 61-year-old Japanese male patient underwent extended endoscopic transsphenoidal surgery for craniopharyngioma. He was undergoing acute treatment for postoperative central diabetes insipidus and hypopituitarism in the intensive care unit. Two days after the surgery, he started to vomit occasionally, despite receiving oral rehydration therapy for central diabetes insipidus. Despite increasing the dose of parenteral hydrocortisone, the periodic vomiting persisted during fasting periods and progressed to aspiration pneumonia and severe sepsis. Abdominal computed tomography was performed to identify the cause of persistent vomiting and revealed the presence of a pseudo-intestinal obstruction extending from the small to large intestine. When oral rehydration therapy for central diabetes insipidus is accompanied by vomiting symptoms suggestive of hypopituitarism, a holistic evaluation of the gastrointestinal system is advisable.

Spinal γ-Aminobutyric Acid Interneuron Plasticity Is Involved in the Reduced Analgesic Effects of Morphine on Neuropathic Pain.

Systemic administration of morphine increases serotonin (5-HT) in the spinal dorsal horn (SDH), which attenuates the analgesic effects of morphine on neuropathic pain through spinal 5-HT3 receptors. We hypothesized that dysfunction of the descending serotonergic system, including the periaqueductal gray (PAG), contributes to attenuate the efficacy of morphine on neuropathic pain through spinal 5-HT3 receptors and GABA neurons. Morphine (100 ng) injected into the PAG produced analgesic effects in normal rats, but not in spinal nerve ligation (SNL) rats. In vivo microdialysis showed that PAG morphine increased the SDH 5-HT concentration in both groups. Intrathecal injection of the 5-HT3 receptor antagonist ondansetron and the GABAA receptor antagonist bicuculline attenuated the analgesic effects of PAG morphine in normal rats, but increased the effects in SNL rats. The increased analgesic effect of PAG morphine induced by bicuculline was reversed by pretreatment with the tropomyosin receptor kinase B (TrkB) antagonist K252a. Activation of spinal 5-HT3 receptors by 2-methyl-5-HT increased the GABA concentration in both groups. Morphine activates GABAergic interneurons in the SDH by activating descending serotonergic neurons. Functional changes in GABAA receptors from inhibitory to facilitatory through the activation of TrkB receptors may contribute to the attenuated efficacy of morphine against neuropathic pain. PERSPECTIVE: Although morphine provides strong analgesia against acute pain, it has limited efficacy against neuropathic pain. This article demonstrates that functional changes in GABAA receptors in the spinal dorsal horn after nerve injury might strongly contribute to the attenuation of opioid-induced analgesia for neuropathic pain.

Hemodynamically adjusted infrahepatic inferior venous cava clamping can reduce postoperative deterioration in renal function: a retrospective observational study.

PURPOSE: Infrahepatic inferior vena cava (IIVC) clamping is beneficial for reducing the amount of bleeding during hepatic surgery, although the associated systemic circulatory deterioration is noticeable. The relationship between changes in the degree of IIVC clamping and postoperative renal function was retrospectively evaluated. METHODS: A total of 59 patients who underwent elective hepatic surgery with surgical IIVC clamping in the two years were analyzed. In 2016, constant 80% clamping of the IIVC was performed (29 cases), and in 2017, hemodynamically adjusted IIVC clamping was performed (30 cases). Intraoperative parameters, including total blood loss and number of blood transfusions, were examined. The use of each vasoactive agents was analyzed. Renal function in the acute postoperative phase was evaluated using serum creatinine (Cr) and estimated glomerular filtration rate (eGFR) values. RESULTS: Comparison of the two groups showed that bolus doses of both ephedrine and phenylephrine were significantly higher in the 2016 group (P = 0.0221, 0.0017). Continuous doses of dopamine were significantly higher in the 2016 group, while those of noradrenaline were not. Postoperative serum Cr levels relative to baseline (%) were significantly higher in the 2016 group immediately after surgery and on postoperative day (POD) 1 (P = 0.0143, 0.0012). Postoperative eGFR relative to baseline (%) was significantly higher in the 2016 group immediately postoperatively and on PODs 1 and 2 (P = 0.0042, 0.0003, 0.0382). CONCLUSION: Hemodynamically adjustable IIVC clamping might be superior to uniformly fixed clamping in preserving renal function without compromising the desired effect on hemostasis.

Loss of endogenous analgesia leads to delayed recovery from incisional pain in a rat model of chronic neuropathic pain.

BACKGROUND: Preoperative pain and impaired endogenous analgesia are risk factors of chronic postsurgical persistent pain (CPSP). A Chronic neuropathic pain model induced by spinal nerve ligation (SNL6W) shows impaired endogenous analgesia and delayed recovery from incisional pain. Repeated amitriptyline treatment can restore the endogenous analgesia, but its effects on delayed recovery are not clear. METHODS: A plantar incision was made on the side contralateral to the nerve ligation in SNL6W rats. Withdrawal thresholds were measured by von Frey filament test until 28 d after surgery. Amitriptyline (10 mg·kg-1·d-1) or vehicle was administered for 13 d perioperatively. To examine the roles of noradrenergic and cholinergic signals in the spinal dorsal horn, pharmacological antagonism, measurement of each neurotransmitter concentration, and immunohistochemistry were conducted. RESULTS: Recovery of the withdrawal threshold of SNL6W animals to pre-incision values required 28 d after surgery, while naive animals recovered within 14 d. Intrathecal injection of alpha2 adrenoceptor antagonist (idazoxan) or muscarinic cholinergic receptor antagonist (atropine) decreased the withdrawal threshold on POD14 and 21 in naive animals, but not in SNL6W rats. Repeated amitriptyline treatment attenuated the delayed recovery in SNL6W rats, and the effect was antagonized by muscarinic cholinergic receptor antagonist. Beside the concentration of acetylcholine and its synthetic enzyme were not altered by the treatment. CONCLUSIONS: Noradrenergic and cholinergic analgesia, which is necessary for normal recovery, is lost in the SNL6W rats. A strategy to enhance endogenous analgesia using antidepressants, rather than simple analgesia, may help to prevent CPSP in chronic pain patients.