Electrical Safety in the Operating Room: Dry Versus Wet

Electrical Safety in the Operating Room: Dry Versus Wet Skip to main page content

HOME CURRENT ISSUE PAST ISSUES CME SUBSCRIBE ONLINE HELP SUBMIT TO A&A ACTIVATE MY ACCOUNT Search GO Advanced Search ? User Name Password Sign In Electrical Safety in the Operating Room: Dry Versus Wet Steven J. Barker, PhD, MD* and D. John Doyle, MD, PhD, FRCPC?

From the *Department of Anesthesiology, University of Arizona College of Medicine, Tucson, Arizona; and ?Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio. Address correspondence and reprint requests to Steven J. Barker, PhD, MD, Department of Anesthesiology, University of Arizona College of Medicine, P.O. Box 245114, Tucson, AZ 85724-5114. Address e-mail to sjbarker{at}u.arizona.edu. A case report in this issue of Anesthesia & Analgesia by Wills et al.1 demonstrates that even today, the operating room (OR) is not always a safe working environment. Despite years of education on electrical safety, combined with policies and precautions dictated by national watchdog agencies such as the National Fire Prevention Agency, a nurse sustained a serious, life-threatening electrical shock while performing her duties in the OR. How could this happen, given our advanced understanding of both the physics and hazards of electricity? To understand and learn from this important case report, we begin with a brief review of some relevant electrical safety principles.

Electricity can stimulate muscle cells to contract, and can thus be used therapeutically in devices such as pacemakers or defibrillators. Electrical current can also trigger grand mal seizures, and this effect is used beneficially in electroconvulsive therapy. However, contact with a large electrical current, whether alternating current (AC) or direct current, can lead to injury or death.

Utility companies supply electrical energy in the form of AC of 120 or 230 V at a frequency of 60 Hz (50 Hz in Europe). The 60 Hz refers to the number of times that the current cycles per second. A typical power cord consists of two conductors. One designated as “hot” carries the current to the load; the other is neutral or “ground” and it returns the current to the source. The root mean square potential difference between the two is 120 V.

To receive a shock, one must contact an electrical circuit at two points, and there must be a potential difference that causes current to flow between those points. When an individual contacts a source of electricity, damage usually occurs in one of two ways. First, the electrical current can disrupt the normal electrical function of cells. Depending on its magnitude, the current can contract muscles, paralyze respiration, cause seizures, or lead to ventricular fibrillation. The second mechanism involves the dissipation of electrical energy throughout the tissues. An electrical current passing through any resistance increases the temperature of that substance. The power dissipated as heat equals the square of the current multiplied by the resistance (P = I2 ? R). If enough thermal energy is released, the temperature will increase sufficiently to produce a burn or cause cellular death.

The severity of an electrical shock is determined by the amount of current (amperes, A) and the duration of the current flow. In medical terms, electrical shocks are usually divided into two categories. Macroshock refers to larger currents (typically more than 10 mA) flowing through a person, which can cause harm or death. Microshock refers to very small currents (as little as 10–50 ?A) and applies only to the electrically susceptible patient, such as an individual who has an internal conduit that is in direct contact with the heart. This conduit can be a pacing wire or a saline-filled central venous or pulmonary artery catheter. In the electrically susceptible patient, even minute amounts of current (10 ?A) may cause ventricular fibrillation.

To understand electrical shock hazards and their prevention, one must have knowledge of grounding. This concept is probably the most confusing aspect of electrical safety, because the same term is used to describe several different principles. By definition, a “ground” is an infinite source or sink for electrons. That is, a ground can absorb or provide infinite amounts of current in response to an applied electrical potential. In practical terminology, grounding refers to two separate principles. The first is the grounding of an electrical power supply and the second is the grounding of electrical equipment. Although electrical power is normally grounded in the home, it is usually ungrounded in the OR. In the home, electrical equipment may be grounded or ungrounded, but it should always be grounded in the OR.

What does all this mean? In an ungrounded or “floating” power supply, a specified potential difference or voltage (e.g., 120 V) is provided between the two power lines or “sides” of the supply. Neither side is connected to ground, and there is thus no potential difference between either side and ground. Conversely, in a grounded power supply, one of the two power lines is physically connected to ground and is thus maintained at zero potential. The “hot” side of the supply will then have the full specified voltage (120 V) between it and the other side, and also between it and any ground source. If one side of a floating power supply accidentally becomes grounded through an equipment fault, no current will flow, but the other side of the supply now becomes hot with respect to ground. In this situation, the unfortunate individual who comes into contact with the hot side of the supply while also being in contact with some sort of ground (standing in a puddle of water usually suffices) will receive a serious macroshock.

The line isolation monitor (LIM) is a device that continuously monitors the integrity of an isolated or floating power system. As noted above, in such a power supply there should be zero potential difference between either side of the supply and ground. The LIM effectively measures this potential difference (technically, it measures the leakage current through a fixed resistance), and gives an alarm when this is significantly greater than zero. If a faulty piece of equipment is connected to the isolated power system, this can ground one side of the supply and change the system back to a grounded system. The faulty piece of equipment will usually continue to function normally. Therefore, it is essential that a warning system be in place to alert the personnel that the power is no longer ungrounded.

Because all AC wiring and electrical devices have some internal capacitance (i.e., have the ability to hold an electrical charge), small leakage currents are normally present, and these will partially degrade the isolation of the system. (For those unfamiliar with capacitance, think of it as a resistance to ground that is infinite for direct current, but gradually decreases with increasing frequency of AC.) The meter of the LIM will indicate (in mA) the total amount of leakage current resulting from stray capacitance, electrical wiring, and any devices plugged into the isolated power system. The reading on the LIM meter does not mean that current is actually flowing; rather, it indicates how much current would flow in the event of a first fault. The LIM is generally set to alarm at 2 or 5 mA, depending on the age and brand of the system. Once this preset limit is exceeded, visual and audible alarms are triggered to indicate that the isolation from ground has been degraded beyond the predetermined limit. This does not necessarily mean that there is an immediate hazard, but rather that the system is no longer totally isolated from ground. It would require a second fault to create a dangerous situation. A ground fault circuit interrupter (GFCI) is a simpler device, and can be thought of as a “poor man's LIM.” Rather than actually measuring the leakage current, the GFCI will trip and shut off all power in that circuit when the leakage current to ground exceeds a critical value.

Thus, armed with knowledge, what can we conclude about the case reported here by Wills et al.? The exact mechanism of the macroshock to this OR nurse may never be known, but we agree with the authors' conclusion that she was “grounded” by kneeling in puddled water on the OR floor. Any faulty piece of equipment or power cord that compromised the isolation of the power supply would provide the remainder of the equation for shock in this operating suite with neither LIMs nor GFCIs. The crucial point here is that inadvertent grounding of both equipment and personnel will occur in an OR. One reason for this is the almost universal presence of liquids (water, blood, gastrointestinal contents, urine, etc.) on the floor. It seems to us that anyone (or any agency) who believes that the OR is a “dry location” has never spent any time in one. On this point, we fully agree with the authors. Yes, there may be ORs that can usually be kept dry. But “usually” is not good enough for this situation, wherein the hazard is great and the precautions for avoiding said hazard are rather simple and inexpensive. LIMs and/or GFCIs seem like inexpensive insurance to us, and yet many (most?) ORs built in the past 25 yr do not have them.

The American Society of Anesthesiologists House of Delegates is about to consider a recommendation from the Committee on Equipment and Facilities regarding this issue (Report 511-1.3). This report recommends to the National Fire Prevention Agency that ORs be considered “wet locations,” but it allows for “opt-out” exceptions if hospitals can offer evidence that their own ORs are dry. We support the primary recommendation to designate ORs as wet, but we are concerned about the opt-out provision, because it might allow hospitals to continue business as usual by claiming that their own ORs are dry.

We would like to see this discussion continue, and the Wills et al. case report provides a good starting point. Our bias at the outset of the discussion is that ORs are never dry locations. Disagree if you wish, but offer evidence to the contrary. And tell it to this unfortunate OR nurse.

Accepted April 17, 2009. Copyright ? 2010 International Anesthesia Research Society REFERENCE 1.? Wills JH, Ehrenwerth J, Rogers D . Electrical injury to a nurse due to conductive fluid in an operating room designated as a dry location. Anesth Analg 2010;110:1647–9 Abstract/FREE Full Text ? Previous | Next Article ?Table of Contents This Article doi: 10.1213/?ANE.0b013e3181ac1d69 A & A June 2010 vol. 110 no. 6 1517-1518 ? Full Text Full Text (PDF) Classifications Editorial Services Email this article to a colleague Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in PubMed Download to citation manager Request Permissions Citing Articles Load citing article information Citing articles via Google Scholar Google Scholar Articles by Barker, S. J. Articles by Doyle, D. J. Search for related content PubMed PubMed citation Articles by Barker, S. J. Articles by Doyle, D. J. Related Content Operating Rooms Equipment Patient Safety Load related web page information Navigate This Article Top REFERENCE Current Issue June 2011, 112 (6) Alert me to new issues of A & A Join the IARS About A&A Mission Editorial Board For Authors For Reviewers Cover Art Sign up Sign up for eTOCs Sign up for RSS feeds Browse by Topic Permissions and Copyright Press Room OpenAnesthesia Advertise in A&A Career Center Most Read Special Article: 2010 Anesthesia & Analgesia Guide for Authors: 2009-2010 Editorial Board, Anesthesia & Analgesia Hand Contamination of Anesthesia Providers Is an Important Risk Factor for Intraoperative Bacterial Transmission Review Article: The Role of the Perioperative Period in Recurrence After Cancer Surgery Postoperative Sore Throat: More Answers Than Questions Electrical Safety in the Operating Room: Dry Versus Wet ? View all Most Read articles Cited The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials ASE/SCA Guidelines for Performing a Comprehensive Intraoperative Multiplane Transesophageal Echocardiography Examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography Consensus Guidelines for Managing Postoperative Nausea and Vomiting Cerebral Autoregulation and Flow/Metabolism Coupling during Cardiopulmonary Bypass: The Influence of Paco2 A Postanesthetic Recovery Score ? View all Most Cited articles Copyright ? 2011 by the International Anesthesia Research Society

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Postoperative Sore Throat: More Answers Than Questions

Postoperative Sore Throat: More Answers Than Questions Skip to main page content

HOME CURRENT ISSUE PAST ISSUES CME SUBSCRIBE ONLINE HELP SUBMIT TO A&A ACTIVATE MY ACCOUNT Search GO Advanced Search ? User Name Password Sign In Postoperative Sore Throat: More Answers Than Questions Phillip E. Scuderi, MD

From the Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina. Address correspondence and reprint requests to Phillip E. Scuderi, MD, Department of Anesthesiology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1009. Address e-mail to pscuderi{at}wfubmc.edu. Postoperative sore throat (POST) is a common adverse event after general anesthesia. Typically, the incidence of POST is highest in patients who are tracheally intubated; however, POST also occurs when a laryngeal mask airway (LMA) is used.1 Even patients who are managed with a facemask are not immune.1 Most of the measures that have been recommended for reducing this complication have been directed at limiting the physical trauma that might result from airway instrumentation and manipulation. Surprisingly few investigations have evaluated pharmacologic interventions as a means of reducing POST. Furthermore, no single drug has achieved widespread acceptance in the clinical community. In this issue of Anesthesia & Analgesia, 4 articles describe simple prophylactic measures that seem to significantly reduce the incidence of POST.2–5 Two of these articles evaluate the effectiveness of topical benzydamine hydrochloride applied to the cuff of the endotracheal tube, directly to the pharyngeal mucosa, or both.2,3 A third article evaluates the efficacy of inhaled fluticasone propionate.4 The fourth article evaluates Strepsils?, a nonprescription lozenge that contains 2 active ingredients, amylmetacresol and 2,4-dichlorobenzyl alcohol.5

When considered in aggregate, these 4 articles raise a number of interesting questions. The expression “sore throat” is obviously common to the vernacular of many different cultures, yet it provides at best a parsimonious description of the actual phenomena. Consequently, the expression “postoperative sore throat” likely represents a broad constellation of signs and symptoms. For instance, in its simplest form, sore throat is a lay description of pharyngitis, which in itself can have a variety of causes. However, sore throat may also include a variety of symptoms including laryngitis, tracheitis, hoarseness, cough, or dysphagia. Postoperatively, it seems most plausible that the symptoms are the result of mucosal injury with resulting inflammation caused by the process of airway instrumentation (i.e., laryngoscopy and suctioning) or the irritating effects of a foreign object (i.e., endotracheal tube, LMA, or oral airway). The site or sites of mucosal injury would obviously vary depending on the airway device. For instance, endotracheal intubation can result in injury to any portion of the pharynx as well as injury to the larynx and trachea. Placement of an LMA can reasonably be expected to cause injury to pharyngeal mucosa in the supraglottic regions only, whereas the use of a facemask with an oral airway should result in injury to only the oropharynx, assuming that no other injuries occurred because of suctioning or other airway maneuvers. It is therefore somewhat surprising to note that the reported incidence of POST after LMA insertion is, at least in some studies, remarkably similar to that seen with endotracheal intubation.6,7 Although this might lead one to infer that the mechanism and location of injury must also be similar, a number of facts seem to contradict this assumption. For instance, reducing the size of endotracheal tubes results in a significant decrease in the incidence of POST.8 The design of tube cuffs has also been an area of intense research. The size, pressure/volume characteristics, and shape of cuff have all been implicated in tracheal mucosal injury and resultant POST.9–12 Conversely, it has been suggested that cuff inflation pressure has less of a role in POST when an LMA is used.6 Both airway devices are clearly capable of inducing mucosal irritation and both can cause POST in patients at rates that are not strikingly different. Yet, anatomically, the site or sites of injury cannot be the same.

There are several interesting observations that arise when one examines the data presented in the 4 articles published in this issue of Anesthesia & Analgesia. The data from Tazeh-kand et al.4 demonstrate that inhalation of fluticasone propionate before the induction of anesthesia significantly reduces the incidence of POST at 1 hour and 24 hours after surgery compared with a placebo control. This is not necessarily an unexpected result. Topical13,14 and systemic steroids15 have been demonstrated to reduce the incidence of POST presumably because of their systemic antiinflammatory effects. More puzzling are the data presented by Ebneshahidi and Mohseni.5 Patients who received a Strepsils lozenge before the induction of anesthesia had a significantly lower incidence of POST and hoarseness both in the postanesthesia care unit and at 24 hours after surgery than did the placebo control group that received a flavored lozenge without the active ingredient. Unless one postulates a systemic effect from the active ingredients in the Strepsils lozenge (i.e., amylmetacresol and 2,4-dichlorobenzyl alcohol), the effect site must be the pharyngeal mucosa. Whereas it is plausible to postulate a reduction on pharyngeal irritation due to the lozenge, it is harder to postulate a mechanism for the reduction in “hoarseness” that was reported in this study. It is also difficult to understand how a preoperative lozenge could reduce a reaction to injury to the larynx and trachea and the resultant laryngotracheitis that must have a role in POST that occurs after intubation.

Conversely, 2 of the articles2,3 describe a reduction in POST with the application of benzydamine hydrochloride to the endotracheal tube cuff alone compared with a placebo control (normal saline and distilled water, respectively). It seems unlikely that the small dose of benzydamine hydrochloride (1.5 and 0.75 mg, respectively) used would have resulted in a systemic effect. Therefore, the reduction in POST that was observed in both of these studies must be assumed to have resulted from a localized decrease in mucosal injury and/or inflammatory response. The incidence of and reduction in POST is strikingly similar when Strepsils lozenges were used when compared with the application of benzydamine hydrochloride to the endotracheal tube cuff. There are unavoidable questions that must be asked: How can a lozenge that is administered orally result in a similar reduction in POST when compared with the topical application of benzydamine hydrochloride to the endotracheal tube cuff? In addition, How can either an oral lozenge or topical antiinflammatory agent applied to an endotracheal tube cuff yield reductions in POST that compare favorably with a more widespread application of topical steroids to both the pharyngeal and laryngotracheal mucosa?

POST is unquestionably a common adverse event after general anesthesia. A number of physical factors have been implicated as noted above. Most notable would seem to be endotracheal tube and cuff design and the approach to airway management (i.e., endotracheal tube, LMA, or mask anesthesia). In addition, female gender, younger patients, gynecologic surgery, and the use of succinylcholine also seem to increase the incidence.16 Of particular note, the use of topical lidocaine appears to confer no benefit and may in fact make POST worse,17,18 a fact that seems to have been confirmed by Hung et al.2 However, what actually causes POST remains something of a mystery. Hoarseness is a physical sign and can certainly be evaluated objectively by a careful observer. Dysphagia, although a symptom, is perhaps less likely to be influenced by intersubject variation in reporting, particularly if questioning is done by a trained observer and is consistently applied. Sore throat is more problematic. As noted above, the location of mucosal injury can vary widely but still result in a subject complaining of a “sore throat.” The 4 articles presented in this issue of Anesthesia & Analgesia describe very different strategies yet all achieved positive results. However, we are no closer to understanding the actual etiology of POST than we were before. A reasonable question to ask is “Does it matter?” I believe that the answer is “yes.” If the precise etiology (or etiologies) of pain after airway management can be determined, it increases the likelihood that a specific therapy or therapies could be recommended that would decrease symptoms and improve outcomes. POST is not the most important adverse event to avoid, at least from a patient's perspective.19 Nevertheless, it is an adverse event that could easily be significantly decreased or even potentially eliminated. The 4 studies presented here may provide the impetus for a more careful evaluation of POST resulting in more precisely targeted therapies.

 Next Section AUTHOR CONTRIBUTIONS PES designed and conducted the study, analyzed the data, and wrote the manuscript. This author approved the final manuscript.

Previous SectionNext Section Footnotes Disclosure: The author reports no conflicts of interest.

Accepted June 14, 2010. Copyright ? 2010 International Anesthesia Research Society Previous Section  REFERENCES 1.? Higgins PP, Chung F, Mezei G . Postoperative sore throat after ambulatory surgery. Br J Anaesth 2002;88:582–4 Abstract/FREE Full Text 2.? Hung NK, Wu CT, Chan SM, Lu CH, Hang YS, Yeh CC, Lee MS, Cherng CH . The effect on postoperative sore throat of spraying the endotracheal tube cuff with benzydamine hydrochloride, 10% lidocaine, and 2% lidocaine. Anesth Analg 2010;111:882–6 Abstract/FREE Full Text 3.? Huang YS, Hung NK, Lee MS, Kuo CP, Yu JC, Huang GS, Cherng CH, Wong CS, Chu CH, Wu CT . The effectiveness of benzydamine hydrochloride spray on the endotracheal tube cuff or oral mucosa for postoperative sore throat. Anesthesia Analg 2010;111:887–91 4.? Tazeh-kand NF, Eslami B, Mohammadian K . Inhaled fluticasone propionate reduces postoperative sore throat, cough and hoarseness. Anesth Analg 2010;111:895–8 Abstract/FREE Full Text 5.? Ebneshahidi A, Mohseni M . Strepsils? tablets reduce sore throat and hoarseness after tracheal intubation. Anesth Analg 2010;111:892–4 Abstract/FREE Full Text 6.? Wakeling HG, Butler PJ, Baxter PJ . The laryngeal mask airway: a comparison between two insertion techniques. Anesth Analg 1997;85:687–90 Abstract/FREE Full Text 7.? Joshi GP, Inagaki Y, White PF, Taylor-Kennedy L, Wat LI, Gevirtz C, McCraney JM, McCulloch DA . Use of the laryngeal mask airway as an alternative to the tracheal tube during ambulatory anesthesia. Anesth Analg 1997;85:573–7 Abstract/FREE Full Text 8.? Stout DM, Bishop MJ, Dwersteg JF, Cullen BF . Correlation of endotracheal tube size with sore throat and hoarseness following general anesthesia. Anesthesiology 1987;67:419–21 CrossRefMedline 9.? Loeser EA, Kaminsky A, Diaz A, Stanley TH, Pace NL . The influence of endotracheal tube cuff design and cuff lubrication on postoperative sore throat. Anesthesiology 1983;58:376–9 Medline 10.? Loeser EA, Bennett GM, Orr DL, Stanley TH . Reduction of postoperative sore throat with new endotracheal tube cuffs. Anesthesiology 1980;52:257–9 CrossRefMedline 11.? Loeser EA, Hodges M, Gliedman J, Stanley TH, Johansen RK, Yonetani D . Tracheal pathology following short-term intubation with low- and high-pressure endotracheal tube cuffs. Anesth Analg 1978;57:577–9 Medline 12.? Loeser EA, Orr DL II., Bennett GM, Stanley TH . Endotracheal tube cuff design and postoperative sore throat. Anesthesiology 1976;45:684–7 Medline 13.? Ayoub CM, Ghobashy A, Koch ME, McGrimley L, Pascale V, Qadir S, Ferneini EM, Silverman DG . Widespread application of topical steroids to decrease sore throat, hoarseness, and cough after tracheal intubation. Anesth Analg 1998;87:714–6 FREE Full Text 14.? Sumathi PA, Shenoy T, Ambareesha M, Krishna HM . Controlled comparison between betamethasone gel and lidocaine jelly applied over tracheal tube to reduce postoperative sore throat, cough, and hoarseness of voice. Br J Anaesth 2008; 100:215–8 Abstract/FREE Full Text 15.? Park SH, Han SH, Do SH, Kim JW, Rhee KY, Kim JH . Prophylactic dexamethasone decreases the incidence of sore throat and hoarseness after tracheal extubation with a double-lumen endobronchial tube. Anesth Analg 2008;107:1814–8 Abstract/FREE Full Text 16.? McHardy FE, Chung F . Postoperative sore throat: cause, prevention and treatment. Anaesthesia 1999;54:444–53 CrossRefMedline 17.? Herlevsen P, Bredahl C, Hindsholm K, Kruh?ffer PK . Prophylactic laryngo-tracheal aerosolized lidocaine against postoperative sore throat. Acta Anaesthesiol Scand 1992;36:505–7 Medline 18.? Loeser EA, Stanley TH, Jordan W, Machin R . Postoperative sore throat: influence of tracheal tube lubrication versus cuff design. Can Anaesth Soc J 1980;27:156–8 Medline 19.? Macario A, Weinger M, Carney S, Kim A . Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg 1999;89:652–8 Abstract/FREE Full Text ? Previous | Next Article ?Table of Contents This Article doi: 10.1213/?ANE.0b013e3181ee85c7 A & A September 24, 2010 vol. 111 no. 4 831-832 ? Full Text Full Text (PDF) Classifications Editorial Services Email this article to a colleague Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in PubMed Download to citation manager Request Permissions Citing Articles Load citing article information Citing articles via Google Scholar Google Scholar Articles by Scuderi, P. E. Search for related content PubMed PubMed citation Articles by Scuderi, P. E. Related Content Ambulatory Postanesthetic Care Unit Complications Load related web page information Navigate This Article Top AUTHOR CONTRIBUTIONS Footnotes REFERENCES Current Issue June 2011, 112 (6) Alert me to new issues of A & A Join the IARS About A&A Mission Editorial Board For Authors For Reviewers Cover Art Sign up Sign up for eTOCs Sign up for RSS feeds Browse by Topic Permissions and Copyright Press Room OpenAnesthesia Advertise in A&A Career Center Most Read Special Article: 2010 Anesthesia & Analgesia Guide for Authors: 2009-2010 Editorial Board, Anesthesia & Analgesia Hand Contamination of Anesthesia Providers Is an Important Risk Factor for Intraoperative Bacterial Transmission Review Article: The Role of the Perioperative Period in Recurrence After Cancer Surgery Postoperative Sore Throat: More Answers Than Questions Electrical Safety in the Operating Room: Dry Versus Wet ? View all Most Read articles Cited The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials ASE/SCA Guidelines for Performing a Comprehensive Intraoperative Multiplane Transesophageal Echocardiography Examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography Consensus Guidelines for Managing Postoperative Nausea and Vomiting Cerebral Autoregulation and Flow/Metabolism Coupling during Cardiopulmonary Bypass: The Influence of Paco2 A Postanesthetic Recovery Score ? View all Most Cited articles Copyright ? 2011 by the International Anesthesia Research Society

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