Comparison of Anterior Suprascapular, Supraclavicular, and Interscalene Nerve Block Approaches for Major Outpatient Arthroscopic Shoulder Surgery A Randomized, Double-blind, Noninferiority Trial
Background The interscalene nerve block provides analgesia for shoulder surgery, but is associated with diaphragm paralysis. One solution may be performing brachial plexus blocks more distally. This noninferiority study evaluated analgesia for blocks at the supraclavicular and anterior suprascapular levels, comparing them individually to the interscalene approach.Methods One hundred-eighty-nine subjects undergoing arthroscopic shoulder surgery were recruited to this double-blind trial and randomized to interscalene, supraclavicular, or anterior suprascapular block using 15  ml, 0.5% ropivacaine. The primary outcome ...
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Supplemental Carbon Dioxide Stabilizes the Upper Airway in Volunteers Anesthetized with Propofol
We present a prespecified, secondary analysis of previously published experiments in 12 volunteers breathingvia a high-flow respiratory circuit used to control upper airway pressure under propofol anesthesia at two levels, with the deep level titrated to suppression of motor response. Ventilation, mask pressure, negative pharyngeal pressure, upper airway closing pressure, genioglossus electromyogram, bispectral index, and change in end-expiratory lung volume were measured as a function of elevation of Petco2 above baseline and depth of propofol anesthesia.Results Petco2 augmentation dose-dependently lowered upper airway cl...
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Differentiating Drug-related and State-related Effects of Dexmedetomidine and Propofol on the Electroencephalogram
Conclusions Electroencephalogram effects of dexmedetomidine and propofol are strongly drug- and state-dependent. Changes in slow-wave and alpha activity seemed to best detect different states of consciousness. (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Noninvasive Tracking of Anesthesia Neurotoxicity in the Developing Rodent Brain
Conclusions Our data demonstrate the feasibility of using the biomarker N-acetyl-aspartate, measured noninvasively using proton magnetic resonance spectroscopy, for longitudinally monitoring anesthesia-induced neurotoxicity. These results also indicate that the neonatal rodent brain is more vulnerable to multiple anesthesia exposures than to a single exposure of the same cumulative duration. (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

γ-Aminobutyric Acid Type A Receptor Potentiation Inhibits Learning in a Computational Network Model
Conclusions Memory formation is widely thought to depend on changes in neuronal connection strengths during learning that enable neuronal groups to respond with greater facility to familiar stimuli. This experiment suggests the ability to form such groups is sensitive to alteration in the balance between excitation and inhibition such as that resulting from administration of a γ-aminobutyric acid–mediated anesthetic agent. (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

History of the Development of Anesthesia for the Dolphin A Quest to Study a Brain as Large as Man ’s
It is important for academic-minded human anesthesiologists to have an interdisciplinary perspective when engaging in cutting-edge research as well as the practice of human anesthesiology. This was a philosophy promoted by Dr. Robert Dripps, former pioneering Chairman of the Anesthesiology Department at the University of Pennsylvania (Philadelphia, Pennsylvania). Many human and veterinary anesthesiologists as well as biomedical engineers and neuroscientists benefited from Dr. Dripps ’s constructive outlook personified in the quest to develop dolphin anesthesiology. The motivation to anesthetize dolphins came from the...
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Should We Stop for Growth Arrest-specific 6 in Acute Respiratory Distress Syndrome?
“…[D]esensitization of anti -inflammatory pathways … may be involved in the inflammatory response seen in ventilator-induced lung injury.” (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Immunotherapy for Sepsis A Good Idea or Another Dead End?
“…[W]hat causes mortality from sepsis?” (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Editor ’s Note: A nesthesiology 2018 Inspiring Investigation and Education
“Being the trusted, authoritative source for quality science and credible information is exactly our goal.” (Source: Anesthesiology)
Source: Anesthesiology - June 20, 2018 Category: Anesthesiology Source Type: research

Acknowledgment
The Editor-in-Chief and the Editors of Anesthesiology would like to thank the following individuals for their participation in the editorial review process. Their contributions are sincerely appreciated. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Instructions for Obtaining A nesthesiology Continuing Medical Education (CME) Credit
(Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Anesthesiology
(Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Protamine-induced Cardiotoxicity Is Prevented by Anti-TNF- α Antibodies and Heparin: Erratum
In the article beginning on page 1389 in the December 2001 issue, Dr. Loker ’s name was listed incorrectly in the byline. It should have appeared as Chaim Locker, M.D. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Inhalational versus Intravenous Induction of Anesthesia in Children with a High Risk of Perioperative Respiratory Adverse Events: A Randomized Controlled Trial: Erratum
In the Online First article published on March 2, 2018, there were several errors in the article ’s abstract. The first sentence of the Methods paragraph should read: “Children (N = 300; 0 to 8 yr) with at least two clinically relevant risk factors for perioperative respiratory adverse events and deemed suitable for either technique of anesthesia induction were recruited and randomized to e ither intravenous propofol or inhalational sevoflurane.” (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Bearing Witness to Anger and Loss
“When we speak, we say only what we know already. When we listen, we may learn something new.”—Dalai Lama (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

On Coming Back
Sound returns (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Neuroimaging of Pain Human Evidence and Clinical Relevance of Central Nervous System Processes and Modulation
Neuroimaging research has demonstrated definitive involvement of the central nervous system in the development, maintenance, and experience of chronic pain. Structural and functional neuroimaging has helped elucidate central nervous system contributors to chronic pain in humans. Neuroimaging of pain has provided a tool for increasing our understanding of how pharmacologic and psychologic therapies improve chronic pain. To date, findings from neuroimaging pain research have benefitted clinical practice by providing clinicians with an educational framework to discuss the biopsychosocial nature of pain with patients. Future a...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Tracheal A-frame Deformity: A Challenging Variant of Tracheal Stenosis
TRACHEAL stenosis after tracheostomy has a reported incidence of 6 to 21% and most commonly occurs secondary to granulation tissue around the stoma or cuff site or circumferential scarring ensuing due to pressure necrosis.1,2 Alternatively, a variant known as a tracheal “A-frame” deformity (see image) can develop, which results from loss of anterior support from tracheal rings.3 Consequently, there is inward collapse of the lateral tracheal walls, which gives the trachea the characteristic “A” shape at the previous stoma site. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Obstructing Respiratory Papillomatosis
LARYNGEAL papillomatosis is a rare condition.1 The image presented is from a 60-yr-old female with a 5-yr history of dysphagia and progressive dyspnea who presented to an outside hospital for pharyngeal biopsy. Intraoperatively, she had complete airway obstruction, an urgent tracheostomy was performed, and she was transferred to our institution for definitive management. See image of intraoperative laryngoscopy demonstrating the exophytic and proliferative growth of laryngeal papillomatosis lesions that contribute to the risk of complete airway obstruction. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Enhanced Needle Visibility by Micro Air Bubble Contrast in Ultrasound-guided Nerve Block
ENSURING optimal needle visualization is paramount for safe and successful ultrasound-guided nerve block.1 Although a variety of technologies have been tried to increase needle visibility during puncture, it is still a challenge to clearly visualize the needle at steep insertion angles, even for experienced practitioners.2 (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Images in Anesthesiology: A Clogged Dialysis Filter Caused by Severe Acutely Induced Hypertriglyceridemia
THE image shows a massive amount of serum fat clogging a dialysis filter in a 55-yr-old cirrhotic surgical patient, who required sedation with propofol for mechanical ventilation after developing hypoxemic respiratory failure. The propofol drip was used for a total of 40  h at an infusion rate of 60 µg · kg–1· min–1 or less, yet serum triglycerides were found to be markedly elevated. Clogging is caused by a triglyceride-induced procoagulant state, with fibrin and clot deposition in the dialysis membrane.1 (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

This Month in Anesthesiology
(Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Big Decisions for Our Little Patients: Mask vs. IV Inductions
Complex Information for Anesthesiologists Presented Quickly and Clearly (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Science, Medicine, and the Anesthesiologist
Key Papers from the Most Recent Literature Relevant to Anesthesiologists (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Streams of Unconsciousness III: Analgesia Reflected in the Acheron …or by Charon?
As depicted in Dante ’sDivine Comedy by French illustrator Gustave Dor é (1832 to 1883), “Charon, the Ferryman of Hell” steered (above) the newly dead across the Underworld ’s River of Woe or Pain or, yes, the River of Aches—the Acheron. To pay Charon to ferry them across, the properly buried dead supplied the oarsman with coins that had been placed under their lifeless tongues. According to Greco-Roman mythology, the plutonic rivers Lethe and Styx supplied amnesia and hypnosis, respectively—properties later prized as hallmarks of general anesthesia. Another such property, analges...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

The McKesson Oxygen Tent: The Role of the Rubber Sheet
By the early 1930s, physician-anesthetist Elmer Isaac “Ira” McKesson, M.D. (1881 to 1935), was developing the concepts behind his McKesson Oxygen Tent (above). To “prevent oxygen from passing through the mattress and escaping from the tent,” a rubber sheet was placed underneath the patient’s sheets and mattress cover. Through a large door in the cabinet, an ice box was completely filled “with cracked ice, the size of one’s fist.” Then, through a s maller door in some hospital-model cabinets, the carbon-dioxide absorber was filled with soda lime and returned to the cabinet. In...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Troup to Waters: Save the Date, August of 1940 …Better Make That 1948
“To Dr.& Mrs. Ralph M. Waters / With all best wishes / from Gilbert Troup. ” So reads a handwritten note (outlined on the right in red) inside this 1939 holiday greeting card from Australian anesthetist Gilbert R. Troup (1896 to 1962) to American anesthesiologist Ralph M. Waters (1883 to 1979). The front of the card wishes “A Merry Christmas and Prosperous New Year…and a Happy Landing in Perth in 1940” for the planned “Australasian Medical Congress (B.M.A.), Perth, August, 1940.” As illustrated on the front of the card, besides flying by plane or sailing directly to Perth, con...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

The French Connection of Somnoforme: Rolland and Rousseau of Bordeaux
For producing analgesia or general anesthesia, the Dental School of Bordeaux ’s Professor Georges Rolland pioneered the use in 1901 of “Soemnoforme.” A 12:7:1 mixture of ethyl chloride, methyl chloride, and ethyl bromide, respectively, this unusual anesthetic was manufactured for worldwide distribution by chemist A. Roussseau, also of Bordeaux. To reassure purchasers a nd frustrate his competitors, that chemist supplied markets worldwide with a green-colored glass bottle for Rolland’s eclectic mixture with raised letters (middle bottle) reading: LE SOEMNOFORME / ANESTHESIQUE GENERAL / A. ROUSSEAU DE...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Gas, Ether, and Jingles from Dr. C. A. Smith of Oneida
Die-cut in the shape of a tambourine with six pairs of jingles, the obverse (left) of this trade card distributed by Dr. C. A. Smith features two egg-filled shoes. Another classic from the Wood Library-Museum ’s Ben Z. Swanson Collection, the card’s reverse (right) invites patients to Dr. Smith ’s dental office (and residence) on Main Street in Oneida, New York. Among his advertising jingles for Oneida residents, Dr. Smith advertised that there was a “Lady always in attendance when Ladies desire Gas or Ether.” (Copyright © the American Society of Anesthesiologists’ Wood Library-Mu s...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Handbook of Anaesthesia & amp; Peri-operative Medicine.
Creating a handbook for all of anesthesia is an undoubtedly daunting task. Cyprian Mendonca and Chandrashekar Vaidyanath should be congratulated for even attempting the feat with theirHandbook of Anaesthesia& Peri-operative Medicine. On one hand, it would have to cover incredibly broad topics with enough detail to be useful to a student, resident, or practicing physician. This book does cover huge swaths of content, with seven major sections totaling 37 chapters covering applied science, perioperative medicine, airway management, specialty-specific procedures, perioperative emergencies, critical care medicine, and pain...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

In Reply
We thank Dr. Hogan for his interest in our article1 and for offering his interpretation of our findings. He is correct that 94% of our subjects exposed to general anesthesia received nitrous oxide. However, the duration of nitrous oxide exposure was variable and often brief. During the time that our cohort of subjects underwent their surgical procedures as infants, it was a common and prevailing practice at our study site to use nitrous oxide during induction only and discontinue it during maintenance. All subjects who received nitrous oxide also received one or more other anesthetics during their surgery. Therefore, our s...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Nitrous Oxide and Decreased White Matter Integrity and Volume during Childhood
(Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

In Reply
We appreciate Dr. Aldwinckle ’s interest in our report1 describing the technique of insertion of a supraclavicular catheter through an infraclavicular entry point. With this approach to the brachial plexus we aim for the fixation of an infraclavicular-access catheter using the flat surface of the pectoral musculature cited by Jeng and Rosenblatt2 and the effectiveness of a supraclavicular single shot, leaving the tip in the corner pocket.3 (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Costoclavicular Approach to the Supraclavicular Fossa: Journey behind the Dark Side of the Moon (Clavicle)
(Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Peripherally Acting μ-Opioid Receptor Agonists Attenuate Ongoing Pain-associated Behavior and Spontaneous Neuronal Activity after Nerve Injury in Rats
Conclusions Peripherally acting μ-opioids may attenuate ongoing pain-related behavior and its neurophysiologic correlates. Yet, repeated administrations cause antiallodynic tolerance. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Endothelin Signaling Contributes to Modulation of Nociception in Early-stage Tongue Cancer in Rats
Background Patients with early stage tongue cancer do not frequently complain of tongue pain. Endothelin-1 signaling is upregulated in the cancerous tongue at the early stage. We tested the hypothesis that endothelin-1 signaling contributes to the modulation of tongue nociception.Methods Squamous cell carcinoma cells were inoculated into the tongue under general anesthesia. Lingual mechanical sensitivity under light anesthesia using forceps from days 1 to 21 (n = 8) and the amounts of endothelin-1 and β-endorphin in the tongue on days 6, 14, and 21 (n = 5 to 7) were examined after the inoculation. The effect of endoth...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Biologic Impact of Mechanical Power at High and Low Tidal Volumes in Experimental Mild Acute Respiratory Distress Syndrome
Conclusions In experimental mild ARDS, even at low VT, high mechanical power promoted ventilator-induced lung injury. To minimize ventilator-induced lung injury, low VT should be combined with low power. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Effects of Prone Positioning on Transpulmonary Pressures and End-expiratory Volumes in Patients without Lung Disease
Background The effects of prone positioning on esophageal pressures have not been investigated in mechanically ventilated patients. Our objective was to characterize effects of prone positioning on esophageal pressures, transpulmonary pressure, and lung volume, thereby assessing the potential utility of esophageal pressure measurements in setting positive end-expiratory pressure (PEEP) in prone patients.Methods We studied 16 patients undergoing spine surgery during general anesthesia and neuromuscular blockade. We measured airway pressure, esophageal pressures, airflow, and volume, and calculated the expiratory reserve vol...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

In Vitro Negative Inotropic Effect of Low Concentrations of Bupivacaine Relates to Diminished Ca 2+ Sensitivity but Not to Ca 2+ Handling or β-Adrenoceptor Signaling
Conclusions We provide evidence that the negative inotropic effect of bupivacaine may be caused mainly by a reduction in myofilament sensitivity to Ca2+. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Ketamine Action in the In Vitro Cortical Slice Is Mitigated by Potassium Channel Blockade
In this study we tested the hypothesis that potassium leak channels contribute to the anesthetic action of ketamine.Methods Adult mouse cortical slices (400 µm) were exposed to no-magnesium artificial cerebrospinal fluid to generate seizure-like event activity. The reduction in seizure-like event frequency after exposure to ketamine (n = 14) was quantified as a signature of anesthetic effect. Pharmacologic manipulation of hyperpolarization-activated cy clic nucleotide-gated and potassium channels using ZD7288 (n = 11), cesium chloride (n = 10), barium chloride (n = 10), low-potassium (1.5 mM) artificial cerebr...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Sodium Channel Nav1.3 Is Expressed by Polymorphonuclear Neutrophils during Mouse Heart and Kidney Ischemia In Vivo and Regulates Adhesion, Transmigration, and Chemotaxis of Human and Mouse Neutrophils In Vitro
Conclusions Nav1.3 is expressed in neutrophilsin vivo; regulates attachment, transmigration, and chemotaxisin vitro; and may serve as a relevant target for antiinflammatory effects of lidocaine. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Association of Polypharmacy with Survival, Complications, and Healthcare Resource Use after Elective Noncardiac Surgery A Population-based Cohort Study
Conclusions Older patients with polypharmacy represent a high-risk stratum of the perioperative population. However, the authors ’ findings call into question the causality and generalizability of the polypharmacy-adverse outcome association that is well documented in nonsurgical patients. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Hyperinsulinemic Normoglycemia during Cardiac Surgery Reduces a Composite of 30-day Mortality and Serious In-hospital Complications A Randomized Clinical Trial
Background Hyperinsulinemic normoglycemia augments myocardial glucose uptake and utilization. We tested the hypothesis that hyperinsulinemic normoglycemia reduces 30-day mortality and morbidity after cardiac surgery.Methods This dual-center, parallel-group, superiority trial randomized cardiac surgical patients between August 2007 and March 2015 at the Cleveland Clinic, Cleveland, Ohio, and Royal Victoria Hospital, Montreal, Canada, to intraoperative glycemic management with (1) hyperinsulinemic normoglycemia, a fixed high-dose insulin and concomitant variable glucose infusion titrated to glucose concentrations of 80 to 11...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Positive End-expiratory Pressure Alone Minimizes Atelectasis Formation in Nonabdominal Surgery A Randomized Controlled Trial
Conclusions During nonabdominal surgery, adequate PEEP is sufficient to minimize atelectasis in healthy lungs and thereby maintain oxygenation. Thus, routine recruitment maneuvers seem unnecessary, and the authors suggest that they should only be utilized when clearly indicated.Visual Abstract An online visual overview is available for this article athttp://links.lww.com/ALN/B728. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Pharmacokinetic/Pharmacodynamic Model of CW002, an Investigational Intermediate Neuromuscular Blocking Agent, in Healthy Volunteers
Conclusions CW002 has predictable pharmacokinetics and is likely to have a rapid onset with an intermediate duration of action at 3 × ED95. This model provides information to inform critical decisions (e.g., dose, study design) for continued development of CW002. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Amisulpride Prevents Postoperative Nausea and Vomiting in Patients at High Risk A Randomized, Double-blind, Placebo-controlled Trial
Background Postoperative nausea and vomiting causes distress for patients and can prolong care requirements. Consensus guidelines recommend use of multiple antiemetics from different mechanistic classes as prophylaxis in patients at high risk of postoperative nausea and vomiting. The prophylactic efficacy of the dopamine D2/D3 antagonist amisulpride in combination with other antiemetics was investigated.Methods This double-blind, randomized, placebo-controlled, international, multicenter trial was conducted in 1,147 adult surgical patients having three or four postoperative nausea and vomiting risk factors. Patients were r...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Does Equi –Minimum Alveolar Concentration Value Ensure Equivalent Analgesic or Hypnotic Potency? A Comparison between Desflurane and Sevoflurane
This study was designed to compare the surgical pleth index and BIS values produced by equi-MAC of desflurane and sevoflurane in patients undergoing single-agent volatile anesthesia.Methods Eighty-nine patients were randomly allocated to two groups receiving either desflurane (n = 44) or sevoflurane (n = 45). Anesthesia was only maintained with assigned volatile anesthetic of age-corrected 1.0 MAC. Surgical pleth index values as an analgesic estimate and BIS values as a hypnotic estimate were obtained under standard tetanic stimulation.Results Post-stimulation surgical pleth index values (mean ± SD), the primary out...
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Etiology of Acute Coronary Syndrome after Noncardiac Surgery
Conclusions The dominant mechanism of perioperative acute coronary syndrome in our cohort was demand ischemia. A subset of patients had no evidence of obstructive coronary artery disease, but findings were consistent with stress-induced cardiomyopathy. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research

Can Mathematical Modeling Explain the Measured Magnitude of the Second Gas Effect?
Conclusions Modeling of ventilation-perfusion inhomogeneity confirms that the second gas effect is greater in blood than in expired gas. Gas-based minimum alveolar concentration readings may therefore underestimate the depth of anesthesia during nitrous oxide anesthesia with volatile agents. The effect on minimum alveolar concentration is likely to be most pronounced for the less soluble volatile agents in current use. (Source: Anesthesiology)
Source: Anesthesiology - May 15, 2018 Category: Anesthesiology Source Type: research