Rui Ping Li

Acupuncture for Pain Relief After Total Knee Arthroplasty: A Call for Clarification.

delivery system is measured over time and compared with 2 dosing strategies of OTMF. Whereas purchasing the bolus device represents a 1-time fixed cost, the cumulative cost of OTMF compounds over time. With once-daily, lowest-dose OTMF (squares), cost equivalence occurs after 2.75 months of continuous use, and after only 12 days when using 7 daily doses of OTMF (circles), a strategy most similar to the study population. Letters to the Editor Regional Anesthesia and Pain Medicine • Volume 40, Number 5, September-October 2015

Comparing intubation performance of Bonfils fiberscope and fiberoptic bronchoscope in difficult pediatric airways.

SIR—The recent article by Kaufmann et al. (1) comparing performance of the Bonfils fiberscope (Bonfils) and the fiberoptic bronchoscope (FOB) for tracheal intubation in difficult pediatric airways was of great interest to us. Their findings have potential implications for selection of fiberoptic intubation tools in managing the difficult pediatric airway. In our view, however, there are several aspects of this study that need to be clarified. First, in their study design, Kaufmann et al. stated that the intubation procedure using the Bonfils or the FOB was started following confirmation of a difficult intubation by repeated direct laryngoscopy in anesthetized, paralyzed children. According to definitions of difficult pediatric airways (2), all airway problems included in this study should be classified into unexpected difficult airway. However, in their Table 1, most of the studied patients were classified as expected difficult airway. We are very interested in knowing the inclusion criterion of expected difficult airway used in this study and how the author differentiated the expected and unexpected difficult airways in their study design. Did difficult intubation with direct laryngoscopy occur in all 21 children with preoperatively suspected difficult airways? Second, in the intubation technique, Kaufmann et al. described: ‘After oral suctioning, if required and visualization of the larynx, the Bonfils was placed under continuous visualization into the middle of the trachea. While an assistant then fixed the tube, the Bonfils was removed’. Due to the narrow pediatric trachea and a 40-degree curved tip of the Bonfils, it is impossible to advance the Bonfils into the middle of the trachea. With the blade of the direct laryngoscope in position, the anesthesiologist often introduces the Bonfils with the right hand in the midline and advances it until its tip reaches the glottis. Then, the tracheal tube is advanced into the trachea along with the stylet of the Bonfils under direct vision (3). We caution against the technique of advancing the tip of the Bonfils through the glottis, because the risk of the laryngeal and tracheal injuries may increase. Furthermore, the time required to obtain the best laryngeal view was not significantly different between the two groups. However, the time required for advancement and correct placement of the tracheal tube into the trachea in the FOB group was more two times of that in the Bonfils group. Apart from the one case where the tracheal tube was accidentally lodged against an arytenoid cartilage while advancing through the glottis, we would like to know what other factors resulted in this prolonged intubation time with the FOB. We believe that such information would be helpful for others who would like to try tracheal intubation using the FOB in pediatric patients with difficult airways. Lastly, this study included pediatric patients with a great age range (0–16 years) and difficult airways due to different factors. As the authors had pointed out in their study limitations, early termination of the study had lowered the power of the study. For example, this study was not powered to show possible differences between the two groups in some of demographic data and difficult airway characteristics, such as age, weight, underlying causes of difficult airways, incidence of restricted mouth opening, average mouth opening, etc. Thus, we cannot exclude the possibility that any imbalance in the above factors would have confounded interpretation of their results.

Is Airwayscope more effective than Macintosh laryngoscope

To the Editor: In a manikin study comparing the Pentax-AWS Airwayscope (AWS) and the Macintosh laryngoscope (MLS) during chest compressions, Kohama et al. [1] showed that the AWS was superior to the MLS. Also, they reported the same results in previous manikin studies simulating chest compressions. However, their results are not supported by a randomized controlled trial in prehospital patients primarily with cardiac arrest, in which the AWS was inferior to the MLS in intubation time, success rate, and difficulty of intubation [2]. In this clinical study, an important cause of failed intubation with AWS on the first attempt is oral contamination, which occurs in 45 of 109 patients. When the AWS lens is obscured by contamination, it needs to be removed and cleaned. Obviously, this requires extra time and affects intubation time and success rate. During intubation with MLS, however, use of a suction device to clean oral contamination is easy, and the MLS does not need to be removed to clean the contamination. Actually, vomitus or secretions cannot be modeled by simple or even sophisticated manikins. Rai and Popat [3] have pointed out that manikin studies often reveal results that are impossible to interpret or are even contradictory to subsequent human studies. Thus, we wish to echo Behringer and Kristensen [4] that manikin studies are of negligible value as sole predictor of any given airway device’s value in the clinical setting.

Nasotracheal intubation with airway scope

To the Editor: In a study assessing the performance of the airway scope (AWS) for nasotracheal intubation (NTI), Ono et al. [1] reported 100 % success with cuff inflation among patients undergoing dental and maxillofacial surgery. They should be congratulated for their efforts in extending use of the AWS in airway management. However, several aspects of this study must be clarified. We believe such information would be useful for others who would like to try NTI with the AWS. First, the design of the AWS used for orotracheal intubation. One of the most important features of the AWS, which facilitates intubation, is a target mark on the monitor. Before advancing the oral tube, the glottis must be positioned at the centre of the target mark. We would like to know whether the same relative positioning of the target mark and the glottis is required for successful NTI. Second, the AWS blade is designed to be inserted posterior to the epiglottis, directly elevating it out of the way. In this study the AWS blade tip was positioned in the vallecula or epiglottis. The detailed reasons for the two blade positions were unclear. Did they affect the laryngoscopic view and subsequent NTI? Third, cuff inflation was used as an aid to NTI with the AWS, but the authors did not specify in which situation this technique was used. In our experience, cuff inflation is effective only when the tube tip is excessively posterior or lateral to the glottis [2]. However, it is ineffective for anterior placement of the tube tip, which must be corrected by other means.

Assessing risk factors for in-hospital acute myocardial infarction after total joint arthroplasty

To the Editor, With great interest we read the recent article by Menendez et al. [1] assessing risk factors for in-hospital acute myocardial infarction (AMI) after total joint arthroplasty in a retrospective cohort study. They showed that advanced age, male gender, Elixhauser comorbidity score, total joint arthroplasty, low household income, history of cardiac disease, valvular disease, diabetes, pulmonary circulation disorders, cerebrovascular disease, peripheral vascular disorders, coagulopathy, AIDS/HIV infection, deficiency anaemia, fluid and electrolyte disorders and the occurrence of concomitant post-operative complications were the independent risk factors for the development of AMI. The strength of this retrospective nationwide study is its use of the Nationwide Inpatient Sample database that includes both a large number of patients with total joint arthroplasty and most of the known factors affecting inhospital morbidity and mortality of such surgical patients. Furthermore, the authors used appropriate statistical methods to identify the independent risk factors for in-hospital AMI. However, one limitation of this study is only the inclusion of pre-operative factors and post-operative complications in multivariate logistic regression analysis for peri-operative factors associated with the development of in-hospital AMI. Some important surgical and intra-operative factors for the development of in-hospital AMI are evidently missed. In patients with total knee or hip arthroplasty, both revision surgery, bilateral surgery and urgent surgery have been identified as independent predictors of post-operative cardiac complications includingAMI [2]. As the weighted mean volume of blood loss is more than 1,000 ml, total joint arthroplasty is one of the leading indications for surgical transfusions, especially for patients with severe comorbidities. In patients undergoing noncardiac surgery, major surgical haemorrhage has been associated independently with an increased risk of post-operative AMI [3]. Furthermore, it has been shown that intra-operative hypotension, tachycardia and hypertension are also associated independently with adverse cardiac events and mortality following noncardiac surgery [4, 5]. Actually, even short durations of an intra-operative mean artery pressure <55 mmHg can result in post-operative myocardial injury, and there is an independent graded relationship between duration of intraoperative hypotension and post-operative myocardial injury and cardiac morbidity [5]. In comparison with pre-operative risk stratification indices alone, the inclusion of intra-operative elements can improve the ability to predict peri-operative mortality and adverse cardiac events [6]. Thus, we believe that their results would have been more informative if the surgical and intra-operative factors were taken into account.

Comparing Postoperative Outcomes for Epidural Versus Intravenous Patient-Controlled Analgesia.

To the Editor: With great interest, we read the recent article by Winer et al comparing influences of epidural versus intravenous patient-controlled analgesia on outcomes after radical cystectomy in a retrospective cohort study. They showed that, despite significant improvements in initial postoperative pain control and less opioid requirement with patient-controlled epidural analgesia, there was no association between 2 analgesic methods in the length of stay, return of bowel function, or postoperative complications. In our view, certain issues in addition to the limitations described may have confounded interpretation of the study’s findings. First, the age of patients in this study ranged from 59 to 74 years. We would like to know whether comorbidities in addition to diabetes were comparable between the 2 groups, particularly cardiovascular and pulmonary comorbidities. It has been shown that baseline comorbidity status is associated with increased postoperative complications, prolonged length of stay, and perioperative mortality in patients undergoing radical cystectomy. Furthermore, in elderly patients with radical cystectomy, impaired preoperative cardiopulmonary reserve is closely related to postoperative major morbidity, prolonged length of hospital stay, and increased use of critical care resource. Second, preoperative hemoglobin and albumin levels were not included in the demographic data of patients. Actually, preoperative anemia caused by hematuria that results from bladder cancer is highly prevalent in patients undergoing radical cystectomy, with an incidence of 75%. In patients with noncardiac surgery, even mild degrees of preoperative anemia have been associated with an increased risk of postoperative mortality and morbidity. Furthermore, hypoalbuminemia is another common problem in patients with cancer. In patients undergoing radical cystectomy, preoperative hypoalbuminemia (<3.5 g/dL) has been identified as an independent predictor of postoperative complications and mortality when controlling for sex, race, ageadjusted Charlson score, body mass index,

Intravenous fenoldopam for acute kidney injury

demographic and surgical variables were comparable between the two series. Furthermore, the small sample size of this study may not exclude a high risk of α statistical error. Because of these limitations, it is difficult to differentiate whether the improved renal function parameters obtained in this study are attributable to the natural recovery process of AKI or the efficiency of fenoldopam. To address this issue, multicentre randomized controlled trials with a large sample size are still needed.

Topical treatments for postoperative sore throat.

To the Editor: In their recent study comparing the effectiveness of Siccoral spray, Stomatovis gargle, and Strefen lozenges on postoperative sore throat (POST), Aydin et al. [1] used a 4-point scale to grade the severity of POST. However, these authors only reported the incidence of POST in the Results section of their publication and did not include data on the severity of POST, such as the median and range of the POST scale. It is therefore unclear—based on the data presented—whether these three topical treatments can significantly attenuate the severity of POST. In the Stomatovis group, patients gargled with Stomatovis gargle for at least 60 s before anesthesia induction. The results showed that gargling with Stomatovis did not significantly reduce POST relative to the control treatment, but the authors did not provide the onset time (interval between treatment and intubation procedure) of this treatment group. In addition to the factors proposed by the authors to contribute to their findings, reported in the Results section, we speculate that a short interval between treatment application and intubation procedure may also affect the efficacy of the treatment. In a previous study evaluating the effectiveness of topical treatments for POST, intubation was performed at least 5 min after gargling [2], which allows for an adequate contact time and in turn enables topical medicine to penetrate into the airway mucosa for maximal effect. Aydin et al. reported that the incidence of POST was similar in all groups at 6 and 24 h post-extubation. Because the effective times of the three topical medicines tested are not provided in their publication, it is difficult to determine whether the results can be attributed to the natural course of POST or to the efficiency of the topical treatments.

Effects of remote ischaemic preconditioning on clinical outcomes after cardiac surgery

To the Editor, In a recent article of Candilio et al 1 assessing the effect of remote ischaemic preconditioning (RIPC) on postoperative outcomes in patients undergoing cardiac surgery, they showed that RIPC reduced the amount of perioperative myocardial injury by 26% and the incidence of acute kidney injury by 48%. They should be applauded for trying to control most of the risk factors affecting postoperative myocardial and kidney injury. However, to differentiate the effects of one factor on study endpoints, all other factors have to be standardised. In this study, several …

Short- and long-term neurologic outcome of elderly patients with out-of-hospital cardiac arrest.

Critical Care Medicine www.ccmjournal.org e33 First, preformed Angpt-2 protein is stored in endothelial cells and is thought to be released into the circulation by early events of systemic inflammation—for example, induction of tumor necrosis factor-α. In turn, released Angpt-2 protein then potentiates the inflammatory response of the endothelium. However, this paradigm fails to explain why the sickest individuals often exhibit a progressive elevation of circulating Angpt-2 as their clinical status deteriorates over days toward death (3). In this light, our recent study provides first-in-kind evidence that sustained biosynthesis of Angpt-2, not simply release of preformed protein, is itself pathological in sepsis. Angpt-2-directed RNAi reduced mortality whether it was administered before or after the induction of experimental sepsis. This new observation also stresses the need to investigate mechanisms that regulate ANGPT2 gene expression in inflammation. Second, heterogeneity—both between affected individuals and within the time course experienced by a single patient— continues to confound efforts to develop novel treatments in sepsis. Personalized treatments may thus be highly desirable. Angpt-2 concentration is easily measured in the blood, and its elevation is strongly associated with other measures of vascular leakage and with hard outcomes such as the future risk of shock or death (3). Measurement of circulating Angpt-2 may thus be a promising approach for identifying patients with sepsis whose molecular pathophysiology is driven by vascular leakage. More broadly, Angpt-2 measurements may be used in future trials not only as an inclusion criterion but also as a means to follow response to therapies targeting the vasculature (whether or not such therapies directly target Angpt-2 itself). Lastly, Zhang et al (1) introduce the concept of a dualaxis vascular therapy, suggesting that combined inhibition of Angpt-2 and vascular endothelial growth factor signaling may yield benefits beyond either approach applied singly. Although preclinical studies offer encouragement regarding such an approach (4), one might worry about the emergence of vascular toxicity from compound approaches as well (5). A careful assessment of the risks and benefits is highly desirable. Ms. Thamm received support for travel. Dr. Parikh consulted for Eunoia Biotech, ICON clinical research, Boston Clinical Research Institute, and Vasomune; has a patent with Beth Israel Deaconess Medical Center; and received support for article research from the National Institutes of Health. Dr. David consulted for Silence Therapeutics. Mr. Stiehl has disclosed that he does not have any potential conflicts of interest.