Seminars in anesthesia最新文献

Upper airway obstruction is a common problem during both sleep and anesthesia, and these tendencies are related in individuals. Patency of the upper airway is determined by the balance of forces across the pharyngeal wall. Airway narrowing, increased extra luminal tissue pressure, and increased airway wall compliance predispose to collapse, particularly during inspiration as negative intraluminal pressures are generated. The tendency to collapse is resisted by airway muscle activation, which is driven by a combination of influences including state-related wakeful stimulation, negative pressure reflexes, and respiratory neuronal activity. This activation decreases with both sleep and anesthesia increasing the tendency to obstruction, and there are substantial overlaps in the way in which these states modulate this neuronal compensatory activity. The common ground between sleep and anesthesia in all these considerations emphasizes the importance of seeking and applying information regarding breathing during sleep to everyday anesthesiology practice.

Maintenance of the pharyngeal airway is an essential task assigned to anesthesiologists for patients’ oxygenation and ventilation during the perioperative period. Based on preoperative identification of risk factors of pharyngeal obstruction such as obstructive sleep apnea (OSA), optimal positioning of the head, neck, mandible, and body is the key for accomplishment of this task. In this context, accumulated knowledge on changes of pharyngeal closing pressures in response to various positional interventions is helpful for determining airway management strategy. Combination of the triple airway maneuver (mandible advancement, head extension, and mouth opening) with sniffing position in the Fowler’s (semi-sitting) position is optimal for anesthesia induction in morbidly obese patients with severe OSA. Disturbance of any one of the elements of the triple airway maneuver indicates tracheal intubation during wakefulness in these patients. Sitting or lateral position is advantageous over supine position for pharyngeal airway maintenance, whereas nasal CPAP should be applied in severe OSA patients.

Despite recent publication of societal guidelines on the perioperative management of obstructive sleep apnea (OSA) patients, the postoperative management of analgesia for patients with OSA is controversial. There are a number of systemic and regional analgesic techniques which may be used for the management of pain in the patient with a diagnosis of OSA but it is unclear if there are advantages of one agent over another. Although the analgesic options for patients with OSA are similar to the options to other surgical patients (e.g., systemic opioids, systemic non-opioids, and regional analgesic techniques), there is a smaller margin for error and the potential for a higher likelihood of complications in the postoperative period for OSA patients. The choice of postoperative analgesia should be tailored to the individual patient’s need including the type of surgical procedure, co-existing diseases, and location of recovery. Although common sense suggests that the postoperative use of opioids and sedative should be minimized while that for non-opioid agents and regional analgesic techniques should be maximized, there is little randomized data to support these notions. Nevertheless, patients with OSA who undergo surgical procedures should receive regional analgesia and non-opioid agents (e.g., NSAIDs) if there are no contraindications for their use. Further studies are needed to examine the different analgesic regimens on OSA patient outcomes.

Obstructive sleep apnea (OSA) is a prevalent condition in the general population. However, a majority of individuals with moderate to severe OSA remain undiagnosed. The polysomnogram (PSG) remains the standard test used in the diagnosis of OSA. However, the time, labor, and costs associated with PSG preclude its widespread use as a routine preoperative screening tool. Increased awareness of signs and symptoms associated with OSA and more standardized methods for screening for the condition may help decrease the disparity between prevalence and diagnosis. The authors discuss polysomnography, breathing disorders associated with sleep, signs and symptoms associated with OSA, and associated co-morbidities.

During sedation and recovery the airway of children with obstructive sleep apnea is vulnerable to collapse. This vulnerability arises from both an inherent collapsibility of the pharyngeal airway in these children and a heightened sensitivity to sedative and anesthetic agents. Pharmacologic and non-pharmacologic support may be required to defend pharyngeal airway patency in children with obstructive sleep apnea both during sedation and recovery.

Venous lactate is a valuable diagnostic test for the evaluation of shock and suspected shock states. Lactate level has been found to correlate with poor prognosis in perioperative, intraoperative, SICU, MICU, and Emergency Department patients, even when vital signs are normal. Patients who respond to resuscitative measures with a decrease in lactate level have a better prognosis than those with persistently elevated lactate levels. In interpreting lactate values it is important to be aware of clinical states, especially liver disease and antiretroviral therapy, which can cause elevations of lactate in the absence of hypoperfusion.

Efferent signaling from the sympathetic nervous system integrates myriad vital functions. Modulation of sympathetic neuron signaling occurs in part by feedback inhibition of neurotransmitter release, mediated largely via α2a and/or α2c adrenergic receptors (α2a&c ARs). This review will describe an overview of our current understanding of α2a&c AR biology, clinical implications of these findings, and the possible clinical importance of genetic variants of α2a&c ARs.

The human genome project may revolutionize our understanding of many cardiovascular diseases and the medications we use to treat them. Why are there variations in disease severity? What causes disease progression in some individuals but not others? Why are there such dramatic differences in response to some therapeutic agents? The human genome project may soon help us answer these questions for patients with disorders ranging from hypertension to congestive heart failure.

Evidence for a relationship between the autonomic nervous system and the immune system has been accumulating. This review will provide a brief overview on the current understanding of how the sympathetic nervous system regulates and modulates the differentiation and function of cells involved in host immune response. In addition, questions regarding the relationship between the sympathetic nervous system and rheumatic as well as other inflammatory disease states will be briefly discussed.