Effects of Intraoperative Opioid Administration on Postoperative Pain and Pain Threshold: A Randomized Controlled Study.

Fentanyl and short-acting remifentanil are often used in combination. We evaluated the effect of intraoperative opioid administration on postoperative pain and pain thresholds when the two drugs were used. Patients who underwent gynecological laparoscopic surgery were randomly assigned into two groups (15 patients each) to receive either sufficient (group A) or minimum (group B) fentanyl (maximum estimated effect site concentration: A: 7.

Phase I study of graft-versus-host disease prophylaxis including bortezomib for allogeneic hematopoietic cell transplantation from unrelated donors with one or two HLA loci mismatches in Japanese patients.

This phase I study was designed for graft-versus-host disease (GVHD) prophylaxis including bortezomib in allogeneic hematopoietic cell transplantation (allo-HCT) from human leukocyte antigen (HLA)-mismatched unrelated donors in Japanese patients. Patients were administered bortezomib on days 1, 4, and 7, with short-term methotrexate and tacrolimus. Three bortezomib dose levels were prepared (1.

Nonpeptide Orexin-2 Receptor Agonist Attenuates Morphine-induced Sedative Effects in Rats.

Background: Sleepiness and decrease in attention are dose-limiting side effects of opioids. The orexin/hypocretin system plays an important role in maintaining wakefulness. This study aimed to explore the potential of a nonpeptide orexin receptor agonist to alleviate morphine-induced sedative effects.

Retrospective evaluation of the effect of carotid artery stenosis on cerebral oxygen saturation during off-pump coronary artery bypasses grafting in adult patients.

Background: It is unknown whether cerebral oxygenation in patients with carotid artery stenosis (CAS) undergoing off-pump coronary artery bypass grafting (CABG) differs from that in patients without CAS. Thus, the effect of the presence of CAS ≥ 50 % on cerebral oxygenation during off-pump CABG in adult patients was evaluated retrospectively.

Methods: Eleven patients with CAS ≥ 50% and 14 patients without CAS ≥ 50% were enrolled.

Perfusion index derived from a pulse oximeter can predict the incidence of hypotension during spinal anaesthesia for Caesarean delivery.

Background: Hypotension during spinal anaesthesia for Caesarean delivery is a result of decreased vascular resistance due to sympathetic blockade and decreased cardiac output due to blood pooling in blocked areas of the body. Change in baseline peripheral vascular tone due to pregnancy may affect the degree of such hypotension. The perfusion index (PI) derived from a pulse oximeter has been used for assessing peripheral perfusion dynamics due to changes in peripheral vascular tone.

Endogenous endomorphin-2 contributes to spinal ĸ-opioid antinociception.

Background/aims: Multiple opioid receptor (OR) types and endogenous opioid peptides exist in the spinal dorsal horn and there may be interactions among these receptor types that involve opioid peptides. In a previous study we observed that antinociceptive effects of the selective κ-opioid receptor (κOR) agonist, U50,488H, was attenuated in μ-opioid receptor (μOR) knockout mice as compared to wild-type mice when administered spinally. This suggests that an interaction between κORs and μORs exits in the spinal cord.

Sitting posture decreases collapsibility of the passive pharynx in anesthetized paralyzed patients with obstructive sleep apnea.

Background: Obstructive sleep apnea (OSA) is an independent risk factor for difficult and/or impossible mask ventilation during anesthesia induction. Postural change from supine to sitting improves nocturnal breathing in patients with OSA. The purpose of this study was to evaluate the effect of patient position on collapsibility of the pharyngeal airway in anesthetized and paralyzed patients with OSA.

Differential analgesic effects of a mu-opioid peptide, [Dmt(1)]DALDA, and morphine.

Aims: H-Dmt-D-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA), a highly selective micro-opioid peptide, is potently analgesic after systemic and intrathecal administration but is less potent given intracerebroventricularly. This study was performed to further characterize the analgesic effects of [Dmt(1)]DALDA.

Methods: We compared the effects of [Dmt(1)]DALDA and morphine after systemic administration in two different acute pain tests, the tail flick test and the paw withdrawal test, and examined how antagonizing the spinal opioid actions would affect their analgesic effects.

Lung volume and collapsibility of the passive pharynx in patients with sleep-disordered breathing.

Lung volume dependence of pharyngeal airway patency suggests involvement of lung volume in pathogenesis of obstructive sleep apnea. We examined the structural interaction between passive pharyngeal airway and lung volume independent of neuromuscular factors. Static mechanical properties of the passive pharynx were compared before and during lung inflation in eight anesthetized and paralyzed patients with sleep-disordered breathing.

Airway protective reflexes evoked by laryngeal instillation of distilled water under sevoflurane general anesthesia in children.

To investigate how sevoflurane modifies airway protective reflexes in anesthetized children, we recruited patients younger than 12-yr-old for our study. Anesthesia was induced with inhaled sevoflurane in oxygen. The airway was managed with a laryngeal mask airway and the patient breathing spontaneously.

Sniffing position improves pharyngeal airway patency in anesthetized patients with obstructive sleep apnea.

Background: Appropriate bag-and-mask ventilation with patent airway is mandatory during induction of general anesthesia. Although the sniffing neck position is a traditionally recommended head and neck position during this critical period, knowledge of the influences of this position on the pharyngeal airway patency is still inadequate.

Methods: Total muscle paralysis was induced with general anesthesia in 12 patients with obstructive sleep apnea, eliminating neuromuscular factors contributing to pharyngeal patency.

Phenotypic variation in cardiovascular responses to acute hypoxic and hypercapnic exposure in mice.

The impact of genetic variation on cardiovascular responses to hypoxia and hypercapnia is not well understood. Therefore, we determined the acute changes in systemic arterial blood pressure (P(SA)) and heart rate (HR) in seven strains of commonly used inbred mice exposed to acute periods of hypoxia (10% O(2)), hypercapnia (5% CO(2)), and hypoxia/hypercapnia (10% O(2) + 5% CO(2)) during wakefulness. Hypercapnia induced an essentially homogeneous response across strains, with P(SA) maintained at or slightly above baseline and with HR exhibiting a typical baroreceptor-mediated bradycardia.

Influences of head positions and bite opening on collapsibility of the passive pharynx.

A collapsible tube surrounded by soft material within a rigid box was proposed as a two-dimensional mechanical model for the pharyngeal airway. This model predicts that changes in the box size (pharyngeal bony enclosure size anatomically defined as cross-sectional area bounded by the inside edge of bony structures such as the mandible, maxilla, and spine, and being perpendicular to the airway) influence patency of the tube. We examined whether changes in the bony enclosure size either with head positioning or bite opening influence collapsibility of the pharyngeal airway.

Ventilatory load compensation response to long-term chest compression in rat model.

Short-term chest compression has been shown to decrease tidal volume and increase respiratory frequency. The present study was designed to assess and characterize the effect of long-term chest compression on breathing pattern and blood gases in awake rats. Chest compression was carried out by inflating a pneumatic cuff placed around the chest to a pressure of 25 mmHg and the pressure was maintained for 28 days.

Ventilating with tracheal gas insufflation and periodic tracheal occlusion during sleep and wakefulness.

Introduction: The current invasive and noninvasive methods for delivering long-term ventilatory support rely on cumbersome patient interfaces that may interfere with upper airway function. To overcome these limitations, a novel system was developed to ventilate conscious, spontaneously breathing dogs through a self-contained cuffed cannula that was used for tracheal gas insufflation (TGI) and periodic tracheal occlusion (PTO). We hypothesized that TGI + PTO would provide greater ventilatory support than would TGI alone and that its effect would be more pronounced during sleep than wakefulness.

Phenotypic differences in the hemodynamic response during REM sleep in six strains of inbred mice.

The pattern of cardiovascular changes that occur at nighttime can have an impact on morbidity and mortality. Rapid-eye-movement (REM) sleep, in particular, represents a period of increased risk due to marked cardiovascular instability. We hypothesized that genetic differences between inbred strains of mice would affect the phenotypic expression of cardiovascular responses that occur in REM sleep.

A model of sleep-disordered breathing in the C57BL/6J mouse.

To investigate the pathophysiological sequelae of sleep-disordered breathing (SDB), we have developed a mouse model in which hypoxia was induced during periods of sleep and was removed in response to arousal or wakefulness. An on-line sleep-wake detection system, based on the frequency and amplitude of electroencephalograph and electromyograph recordings, served to trigger intermittent hypoxia during periods of sleep. In adult male C57BL/6J mice (n = 5), the sleep-wake detection system accurately assessed wakefulness (97.

Usefulness of continuous oxygen insufflation into trachea for management of upper airway obstruction during anesthesia.

Background: Severe complications associated with upper airway obstruction often occur during the perioperative period. Development of a simple and reliable technique for reversing the impaired airway patency may improve airway management. The purpose of the current study is to evaluate the usefulness of transtracheal oxygen insufflation (TTI) for management of upper airway obstruction during anesthesia and to explore the mechanisms of TTI in detail.

Efficacy of endoscopic static pressure/area assessment of the passive pharynx in predicting uvulopalatopharyngoplasty outcomes.

Objectives/hypothesis: Although uvulopalatopharyngoplasty (UPPP) is an attractive surgical treatment for obstructive sleep apnea (OSA), the unpredictable outcome limits application of the procedure. Since UPPP corrects only retropalatal airway (RP) patency, we hypothesized that response to UPPP is determined by collapsibility of the retroglossal airway (RG), where UPPP does not correct.

Methods: We estimated closing pressure (Pclose) for each pharyngeal segment by endoscopically obtaining the static pressure/area relationship of the passive pharynx in completely paralyzed and anesthetized patients with sleep-disordered breathing (n = 41) before UPPP.

Upper airway reflexes during a combination of propofol and fentanyl anesthesia.

Background: The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. The purpose of the present study was to characterize respiratory and laryngeal responses to laryngeal irritation during increasing doses of fentanyl under propofol anesthesia.

Methods: Twenty-two female patients anesthetized with propofol and breathing through the laryngeal mask airway were randomly allocated to three groups: (1) eight patients who received cumulative total doses of 200 microg fentanyl given in the form of two doses of 50 microg and one dose of 100 microg spaced 6 min under mechanical controlled ventilation while end-tidal carbon dioxide tension (PCO2) was maintained at 38 mmHg (fentanyl-controlled ventilation group), (2) eight patients who received cumulative total doses of 200 microg fentanyl while breathing spontaneously while end-tidal PCO2 was allowed to increase spontaneously (fentanyl-spontaneous ventilation group), and (3) six spontaneously breathing patients who were anesthetized with propofol alone (propofol group).

Pharyngeal patency in response to advancement of the mandible in obese anesthetized persons.

Background: During anesthesia in humans, anterior displacement of the mandible is often helpful to relieve airway obstruction. However, it appears to be less useful in obese patients. The authors tested the possibility that obesity limits the effectiveness of the maneuver.

Nasal inhalation of l-menthol reduces respiratory discomfort associated with loaded breathing.

To test the hypothesis that stimulation of cold receptors in the upper airway may alleviate the sensation of respiratory discomfort, we investigated the effects of nasal inhalation of l-menthol (a specific stimulant of cold receptors) on the respiratory sensation and ventilation during the loaded breathing in 11 normal subjects. Subjects were asked to rate their sensation of respiratory discomfort using a visual analog scale (VAS) while breathing on a device with a flow-resistive load (180 cm H2O/L/s) or with an elastic load (75.5 cm H2O/L).

Cough and other reflexes on irritation of airway mucosa in man.

Both human and animal studies show that irritation of airway mucosa elicits a variety of reflex responses such as coughing, apnoea, and laryngeal closure. Most of the information concerning these reflex responses were obtained in anesthetized conditions with little applicability to awake conditions. Various aspects of cough and other reflexes on irritation of the airway mucosa are discussed.