Correspondence Fire Risk with Nasal Cannula Oxygen Dear Editor: Huddleston et al1 raise awareness of fire hazards with supplemental oxygen during ophthalmic plastic surgery and succinctly outline the variables that contribute to devastating operating room fires. We question the conclusion that “insisting on nasal cannula use should be our next step toward eliminating surgical fires.” Several studies demonstrate the fire dangers of oxygen supplementation via nasal cannula. The number of locations in the facial field that breach thresholds for combustion risk may correlate directly with flow rate.2-4 Huddleston et al do not provide flow rates that may be relevant. Nevertheless, even at low flow rates, nasal cannulated oxygen may still cause serious fire hazards during oculofacial surgery with ignition sources such as cautery or laser in close proximity. Although there are limitations with each, we are aware of 3 strategies to reduce the risk of fire with nasal cannulated oxygen: (1) The Emergency Care Research Institute recommends stopping supplemental oxygen 1 minute before and during the use of electrocautery devices or lasers, (2) Engel et al5 describe a modified nasopharyngeal tube to direct oxygen into the posterior pharynx, and (3) we described the use of a midfacial seal drape to achieve a barrier between excess oxygen and the surgical field.2 Operating room fires are underreported and represent a preventable cause of morbidity and mortality. Further attention to the topic may clarify the safest methods for oxygen delivery during oculofacial surgery and forestall further devastating events.

KRISTIN E. HIRABAYASHI, BA JEREMIAH P. TAO, MD, FACS University of California, Irvine, California

References 1. Huddleston S, Hamadani S, Phillips ME, Fleming JC. Fire risk during ophthalmic plastic surgery. Ophthalmology 2013;120: 1309. 2. Tao JP, Hirabayashi KE, Kim BT, et al. The efficacy of a midfacial seal drape in reducing oculofacial surgical field fire risk. Ophthal Plast Reconstr Surg 2013;29:109–12. 3. Meneghetti SC, Morgan MM, Fritz J, et al. Operating room fires: optimizing safety. Plast Reconstr Surg 2007;120:1701–8. 4. Orhan-Sungur M, Komatsu R, Sherman A, et al. Effect of nasal cannula oxygen administration on oxygen concentration at facial and adjacent landmarks. Anaesthesia 2009;64:521–6. 5. Engel SJ, Patel NK, Morrison CM, et al. Operating room fires: part II. Optimizing safety. Plast Reconstr Surg 2012;130: 681–9.

Author reply Dear Editor: We appreciate the opportunity to discuss the recent report on innovative draping methods to minimize elevated oxygen concentrations in ophthalmic surgical fields.1 We agree that using a standard nasal cannula does not absolutely eliminate the risk of fire during ophthalmic surgery, but we still

assert that it is safer than using a face mask. One of the studies cited by Tao and Hirabayashi found oxygen levels higher than atmospheric (25.8%) at the left lateral canthus when delivering oxygen via nasal cannula at relatively high flow rates (6 liters/min).2 Readings were performed on supine volunteers simulating patients undergoing cervical node biopsy.2 Near atmospheric oxygen levels were found around the eyes at low to normal flow rates between 2 and 4 liters/min O2.2 However, Tao et al1 found average oxygen levels up to 31.3% in the ophthalmic surgical field using patient simulator mannequins at high flow rates (6 liters/min). In our investigation, we prospectively studied openface draped patients undergoing ophthalmic plastic surgery receiving oxygen via nasal cannula or face mask.3 We found that patients receiving oxygen via nasal cannula at normal flow rates had near atmospheric oxygen levels in the periocular area.3 To put these results into perspective, when we delivered oxygen via face mask at 5 liters/min O2, we obtained average readings up to 38.9% O2 in the periocular area. Our highest average reading was 63.7% O2 at the glabella, which occurred when providing oxygen at 10 liters/min via face mask. Our original manuscript went into greater detail on the effect of flow rate, but its scope was limited at the journal’s request. We also agree with recommendations put forth by The Emergency Care Research Institute, and find promise in the techniques outline in the recent article by Tao et al.1 They clearly provide another way to make oculofacial surgery safer. We still stand by our original statement that nasal cannula is a better choice over face mask for ophthalmic plastic surgery.

STEPHEN HUDDLESTON, MD JAMES C. FLEMING, MD, FACS MARGARET E. PHILLIPS, MD SYEDA HAMADANI, MD Department of Ophthalmology, University of Tennessee Ophthalmology, Memphis, Tennessee

References 1. Tao JP, Hirabayashi KE, Kim BT, et al. The efficacy of a midfacial seal drape in reducing oculofacial surgical field fire risk. Ophthal Plast Reconstr Surg 2013;29:109–12. 2. Orhan-Sungur M, Komatsu R, Sherman A, et al. Effect of nasal cannula oxygen administration on oxygen concentration at facial and adjacent landmarks. Anaesthesia 2009;64:521–6. 3. Huddleston S, Hamadani S, Phillips ME, Fleming JC. Fire risk during ophthalmic plastic surgery. Ophthalmology 2013;120. 1309-9.

Temporal Artery Biopsy Dear Editor: The recent article describing the clinical practice patterns for temporal artery biopsy as a mean of diagnosing giant cell arteritis (GCA) by Schallhorn et al1 provides important data that can inform the current practice. This article evaluated the preferred approach to diagnose GCA by temporal artery biopsy through a survey sent to oculoplastic surgeons, neuro-ophthalmologists, and rheumatologists. However, we believe additional information missed in the article is required to interpret their results.

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Ophthalmology Volume 120, Number 12, December 2013 Giant cell arteritis is a systemic vasculitis of large and mediumsized blood vessels.2 It does not involve small blood vessels as stated in the companion manuscript. There are 2 distinguished clinical phenotypes observed in patients with GCA. Cranial vessel GCA can cause unilateral temporal headache, jaw claudication, facial pain, anterior ischemic optic neuropathy, or amaurosis fugax. This is the most frequent clinical phenotype that oculoplastic surgeons and neuro-ophthalmologists encounter. Moreover, GCA can present with musculoskeletal symptoms or arm claudication. This large-vessel GCA is linked to the HLAeDRB1*0404 allele, which has also been associated with rheumatoid arthritis.3 Rheumatologists face more often large-vessel GCA than ophthalmologists. It is known that temporal artery biopsy has a higher diagnostic yield for cranial GCA,2 especially when visual symptoms are present.4 The lower diagnostic yield of temporal artery biopsy for large-vessel GCA may explain that 22% of rheumatologists indicated primarily bilateral biopsy, compared with 8% and 6% of neurologists and oculoplastic surgeons. We believe that the great variation in practice patterns pointed out by Schallhorn et al1 may be a reflection of the different phenotypes of GCA that those physicians encounter in their daily practice. Furthermore, a big flaw of the Schallhorn’s study was to disregard the role of imaging modalities (high-resolution color duplex ultrasonography, magnetic resonance angiography, positron emission tomography) in the management of GCA. Despite temporal artery biopsy is still considered the gold standard for GCA diagnosis, color duplex ultrasonography has been proposed as a noninvasive tool for guidance of temporal artery biopsy, GCA diagnosis, and monitoring treatment response in patients with GCA.5 There is an ongoing debate, especially among rheumatologists, about the usefulness of color duplex ultrasonography, and that was not tested in the survey. Maybe the low response rate among subspecialists, particularly low among rheumatologists is linked to the incorporation of this tool or other imaging modalities to their preferred clinical practice algorithm, which was not evaluated in the survey.

ANA M. SUELVES, MD ENRIQUE ESPAÑA GREGORI, MD, PhD MANUEL DÍAZ-LLOPIS, MD, PhD Department of Ophthalmology, University and Polytechnic Hospital La Fe, Valencia, Spain

References 1. Schallhorn J, Haug SJ, Yoon MK. A national survey of practice patterns: temporal artery biopsy. Ophthalmology 2013;120:1930–4. 2. Brack A, Martinez-Taboada V, Stanson A, et al. Disease pattern in cranial and large-vessel giant cell arteritis. Arthritis Rheum 1999;42:311–7. 3. Charpin C, Balandraud N, Guis S, et al. HLA-DRB1*0404 is strongly associated with high titers of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis. Clin Exp Rheumatol 2008;26:627–31. 4. Suelves AM, España-Gregori E, Aviñó J, et al. Analysis of factors that determine the diagnostic yield of temporal artery biopsy. Arch Soc Esp Oftalmol 2013;88:127–9. 5. Arida A, Kyprianou M, Kanakis M, et al. The diagnostic value of ultrasonography-derived edema of the temporal artery wall in giant cell arteritis: a second meta-analysis. BMC Musculoskelet Disord 2010;11:44.

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Author reply Dear Editor: We appreciate Suelves, Gregori, and Diaz-Llopis’ interest in our recent article “A National Survey of Practice Patterns: Temporal Artery Biopsy.”1 In this study, we surveyed neuroophthalmologists, oculoplastic surgeons, and rheumatologists regarding temporal artery biopsy practices in the assessment of patients suspected to have giant cell arteritis (GCA). Specifically, we questioned practitioners as to whether they favored unilateral or bilateral temporal artery biopsy and their thoughts regarding the effect of prior corticosteroid therapy on biopsy findings. In short, responses varied greatly within and between specialists. Of slightly >1000 respondents, 37% recommended unilateral biopsy alone, 29% recommended initial unilateral biopsy with biopsy of the contralateral side if the first side is negative, 18% recommended bilateral biopsy in all cases, and 16% stated that their preference depended on the degree of suspicion. Most respondents believed that biopsies remained accurate for >14 days after initiating steroid therapy. Seulves et al raise 2 questions. First, they state, “We believe that the great variation in practice patterns pointed out by Schallhorn et al may be a reflection of the different phenotypes of GCA that those physicians encounter in their daily practice.” Although our understanding of the specifics of the proposed GCA subtypes is evolving and somewhat controversial, differences do exist.2 We agree that “phenotype” influences to whom patients present, and may explain at least in part differences observed in practice patterns. We refer Seulves et al to the Discussion in our article,1 where we state that: Different subspecialists often treat different subsets of patients and play different roles in patient management. Although rheumatologists treat patients with severe GCA, they also tend to manage patients with mild disease, when an acute ischemic event may not have occurred. Ophthalmologists tend to treat GCA patients with more advanced or rapidly progressive disease after ocular ischemic events . these varying provider roles may explain in part the differences in TAB practice patterns. Suelves’ suggestion that the sensitivity and specificity of temporal artery biopsies varies among patients with different phenotypes is noteworthy and interesting. We respectfully disagree with the second assertion by Suelves et al, “a big flaw of the Schallhorn’s study was to disregard the role of imaging modalities.” Our study design was tailored to assess temporal artery biopsy practice patterns, and was clearly stated as such. It was not designed to assess or compare temporal artery biopsy with other diagnostic modalities. We acknowledge that despite being a relatively benign procedure, complications do occur with temporal artery biopsy.3 To maximize patient safety as well as to control healthcare costs, as is the trend in many fields of medicine, less invasive techniques are being sought. Several modalities, such as ultrasonography, have been proposed as alternatives to temporal artery biopsy. Although less invasive tests may gain more widespread acceptance and use, at present their appropriate role is still being defined. Regardless, this does not alter or influence the findings of our study, in which we illustrate and emphasize the lack of agreement with regard to temporal artery biopsy practice patterns among physicians caring for patients with possible GCA.

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