The Airway Management Guideline is supposed to serve as a tool for orientation and decision -making and as such it contributes to the optimal treatment of anesthaesiology and intensive medical care patients: A preanaesthesiological evaluation searches for anatomical and physiological indications for a difficult mask ventilation and intubation. This includes the evaluation of the patient's mouth opening, dental status, protrusion of the lower jaw, range of motion of the cervical spine and existing pathologies. Securing the aiways should proceed while spontaneous breathing is maintained, provided that predictors or anamnestical indications of a difficult or impossible mask ventilation and / or endotraheal intubaton exist. Various techniques may be applied to this end. In case of an unexpected difficult airway, using a videolaryngoscope will be recommended after an unsuccessful direct laryngoscopy. For this reason, a videolyarygoscope should be available at each and every anaesthesiological workplace. In case of patients who are at risk of aspiration or patients who are critically ill, the airways should be primarily secured with the aid of a videolaryoscope. Se- curing the airways by translaryngeal and transtracheal techniques is the last resort in airway management. The execution and / or supervision of securing airways at the ICU lies in the competence of the medical and nursing staff who are experienced in securing airways. Both a solid qualification and regular training courses are essential. Clear communica- tion and interactions among team mem- bers are obligatory prior to every single airway securement. Once an airway has been secured the correct position of the endotracheal tube must be ascertained by means of capnography.

The German airway management guidelines are intended to serve as an orientation and decision-making aid and thus contribute to the optimal care of patients undergoing anesthesiologic- and intensive medical care. As part of the pre-anesthesiologic evaluation, anatomical and physiological indications for difficult mask ventilation and intubation shall be evaluated. This includes the assessment of mouth opening, dental status, mandibular protrusion, cervical spine mobility and existing pathologies. The airway shall be secured while maintaining spontaneous breathing if there are predictors or anamnestic indications of difficult or impossible mask ventilation and/or endotracheal intubation. Various techniques can be used here. If there is an unexpectedly difficult airway, a video laryngoscope is recommended after unsuccessful direct laryngoscopy, consequently a video laryngoscope must be available at every anesthesiology workplace. The airway shall primarily be secured with a video laryngoscope in critically ill- and patients at risk of aspiration. Securing the airway using translaryngeal and transtracheal techniques is the “ultima ratio” in airway management. The performance or supervision of airway management in the intensive care unit is the responsibility of experienced physicians and nursing staff. Appropriate education and regular training are essential. Clear communication and interaction between team members are mandatory before every airway management procedure. Once the airway has been secured, the correct position of the endotracheal tube must be verified using capnography.

BACKGROUND:The evaluation of German postanesthesia questionnaires is often restricted to inpatient medical care. The anesthesiological questionnaire for patients (ANP) has previously been validated only after medical care of inpatients. Therefore, the aim of the present study was to evaluate the validity of the ANP in the context of outpatient surgery and anesthesia. METHODS:Data from 4547 patients (mean age 18-89 years, sex: m/f, 55%/45%), scheduled for ambulatory orthopedic and trauma surgery, were analyzed. All patients received a standard induction of anesthesia with propofol, sufentanil and 4 mg dexamethasone. Maintenance of anesthesia was achieved with a balanced technique comprising volatile anesthesia (either sevoflurane or desflurane) and sufentanil. In addition, patients undergoing operations on the anterior cruciate ligament received a femoral nerve block with 12-15 ml 0.5% ropivacaine. Of the patients 13% remained in hospital overnight as a result of complex operations (combined anterior and posterior cruciate ligament repair, hip arthroscopy and 10% of those undergoing shoulder operations). Before discharge from the recovery room, patients were asked to answer questions with respect to postoperative symptoms 1h after anesthesia (ESNA 19 items), at the time of interview (ABZ 17 items) and about overall patient satisfaction (10 items). These results were matched with the type of procedure and time data from the patient administration system. All data were analyzed descriptively using parametrical tests. RESULTS:At both time points, pain in the area of the operation was the predominant symptom (ESNA: 77,1%; ABZ: 74,3%). Pain after shoulder arthroscopy was more severe compared to knee arthroscopy, both with and without repair of the anterior cruciate ligament. Most of the adverse symptoms decreased significantly (p ≤ 0.001) with time, demonstrating progressive recovery of the patient. Patient discomfort was more likely to occur in female than in male patients, and female patients were more likely to be dissatisfied with the progress of recovery. The risk of experiencing adverse symptoms after anesthesia was higher for female than for male patients; this was most apparent for feeling cold (odds ratio, OR 4.08) and nausea and vomiting (OR 3.45). Younger patients (18-40 years) were more likely to express discomfort than both groups of older patients (41-60 years and 61-89 years). Accordingly, younger patients had lower satisfaction levels with respect to both anesthesia and overall perioperative care, and the progress of recovery. Postoperative nausea and vomiting (PONV) were linked to younger age, female sex, and longer procedure times (>40 min). CONCLUSION:The individual analyses delivered plausible results, which support the validity of the ANP. The ANP may also be used for assessment of postoperative discomfort and patient satisfaction in the setting of outpatient surgery. In view of the short time interval between the two measurement points, the ANP for outpatients could in future be reduced to a single postoperative questionnaire.

Die Evaluation deutschsprachiger postanästhesiologischer Fragebogen zur Versorgungsqualität beschränkt sich häufig auf den stationären Bereich. Auch der Anästhesiologische Nachbefragungsbogen für Patienten (ANP) wurde bisher nur im stationären Kontext verwendet. Ziel dieser Untersuchung war die Validierung des ANP für den ambulanten Bereich. Es wurden die Daten von 4547 Patienten (18 bis 89 Jahre; 55,2 % Männer, 44,5 % Frauen), welche einen ambulanten orthopädischen oder unfallchirurgischen Eingriff erhielten, analysiert. Kurz vor ihrer Entlassung beantworteten die Patienten Fragen zu postoperativen Symptomausprägungen in der ersten Stunde nach Anästhesie (ESNA) und zum aktuellen Befragungszeitpunkt (ABZ) sowie Fragen zur Patientenzufriedenheit. Zudem wurden aus dem Abrechnungssystem Daten zur Eingriffsart und den Versorgungszeiten bezogen und mit den ANP-Daten in eine gemeinsame Analysedatei konvertiert. Die Datenauswertung erfolgte deskriptiv. Es wurden parametrische Testverfahren eingesetzt. Zu beiden Befragungszeitpunkten waren Schmerzen im Operationsgebiet (ESNA: 77,1 %; ABZ: 74,3 %) die häufigsten Beschwerden der Patienten. Nach Schulterarthroskopien äußerten die Patienten vergleichsweise stärkere Schmerzen als nach einer Kniearthroskopie oder vorderen Kreuzbandplastik. Die meisten negativen Symptome zeigten sich im zeitlichen Verlauf signifikant (p ≤ 0,001) rückläufig. Frauen und junge Patienten (18–40 J.) äußerten mehr postoperative Beschwerden als Männer und ältere Patienten (>40 J.) und gaben geringere Zufriedenheitswerte an. Das weibliche Geschlecht, ein junges Alter und lange Operationszeiten (>40 min) ließen sich als Einflussvariablen für postoperative Übelkeit und Erbrechen identifizieren. Insgesamt ergaben die Analysen der Einzelaspekte plausible Ergebnisse und sprechen somit für die Validität und Praxistauglichkeit des ANP im ambulanten Bereich.

Editor—We read with interest the article by Kleine-Brueggeney and colleagues,1Kleine-Brueggeney M Greif R Schoettker P Savoldelli GL Nabecker S Theiler LG. Evaluation of six videolaryngoscopes in 720 patients with a simulated difficult airway: a multicentre randomized controlled trial.Br J Anaesth. 2016; 116: 670-679Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar who compared six videolaryngocopes during routine airway management in patients with simulated difficult airways. We congratulate the authors for undertaking this study, because a comparison of six different devices in a clinical setting is ambitious. In addition, because of the growing availability of different videolaryngoscopes on the market, a comparison of both intubation success and handling between the different devices is of great importance. Nevertheless, after carefully reading the article, we believe that there are some aspects that need to be addressed further. These authors compared the videolaryngoscopes by A.P. Advance, C-MAC D-Blade, McGrath, KingVision, Airtraq, and GlideScope in patients with simulated limited mouth opening and neck movement. The videolaryngoscopes that performed best were the McGrath and the C-MAC D-Blade; the McGrath was the only videolaryngoscope that reached the hypothesized first-attempt success rate of 0.9 within the predefined confidence interval. According to the authors, the videolaryngoscopes were chosen to represent three channelled and three non-channelled devices. However, the blade design of the videolaryngoscopes differed in another important aspect that is not addressed further by the authors. Of the six videolaryngoscopes, there are five with highly angulated blades, namely C-MAC D-Blade, GlideScope, KingVision, Airtraq, and A.P. Advance with difficult airway blade. In contrast, the McGrath as the sixth videolaryngoscope was chosen with a MAC blade. Even though the authors stated in their methodology paper2Theiler L Hermann K Schoettker P et al.SWIVIT–Swiss video-intubation trial evaluating video-laryngoscopes in a simulated difficult airway scenario: study protocol for a multicenter prospective randomized controlled trial in Switzerland.Trials. 2013; 14: 94Crossref PubMed Scopus (18) Google Scholar that the McGrath MAC is a further development of the original McGrath Series 5, the blade design of the two series differs significantly. The McGrath MAC used in the present study has a Macintosh-type blade that is very similar to a conventional laryngoscope blade that anaesthesiologists use in their daily practice. In contrast, the McGrath Series 5 has a highly angulated blade that would have compared much better with the other five videolaryngoscopes in the present study. Thus, one Macintosh-type blade almost every anaesthesiologist is familiar with was compared with five curved blades. Proper handling of curved blades requires a significant amount of training. The important difference between Macintosh-type and highly angulated blades with regard to handling and intubation success has been addressed by several studies.3Teoh WHL Saxena S Shah MK Sia ATH. Comparison of three videolaryngoscopes: Pentax Airway Scope, C-MAC™, Glidescope® vs the Macintosh laryngoscope for tracheal intubation.Anaesthesia. 2010; 65: 1126-1132Crossref PubMed Scopus (82) Google Scholar4Alvis BD Hester D Watson D Higgins M St Jacques P. Randomized controlled trial comparing the McGrath MAC video laryngoscope with the King Vision video laryngoscope in adult patients.Minerva Anestesiol. 2016; 82: 30-35PubMed Google Scholar However, this aspect was not addressed further in the present study. Readers might become puzzled because of the incomplete description of the videolaryngoscopes used in this study. In the flowchart, use of the C-MAC is clearly stated as D-Blade, both GlideScope and Airtraq are self-explainable curved blades, and the McGrath blade type has been discussed above. However, A.P. Advance and KingVision have no further description of their blade types, at least in the flowchart, so that it is not clear whether the A.P. Advance is used with the Mac-blade (as usually done) or the difficult airway blade, and the KingVision could also be used with a non-channelled blade. Exact classification of the studied material is of paramount importance, especially for A.P. Advance and KingVision, for which few data are available. Finally, the number of missing data for insertion of the device into the oropharynx, quality of view, and ease of tube insertion are not proportional between the different devices tested, and ranges between 9 (A.P. Advance) and 0 (McGrath). None declared.

Seit der ersten deutschen „Leitlinie Atemwegsmanagement“ im Jahr 2004 haben sich neue Techniken im klinischen Alltag etabliert, und es wurden neue Erkenntnisse zu bestehenden Strategien publiziert. Konsequenterweise stellt die neue „Leitlinie Atemwegsmanagement“ der Deutschen Gesellschaft für Anästhesiologie und Intensivmedizin den aktuellen Stand der Wissenschaft dar und integriert die derzeit empfohlenen Techniken und Strategien. Die vorliegende Leitlinie soll dazu beitragen, eine optimale Versorgung der anästhesiologisch betreuten Patienten zu gewährleisten. Sie soll dem Anwender zur Orientierung und als Entscheidungshilfe dienen.

Since the publication of the first German guidelines on airway management in 2004 new techniques have been established in the clinical routine and new insights into existing strategies have been published. As a consequence the new guidelines on airway management of the German Society of Anesthesiology and Intensive Care Medicine represent the current state of scientific knowledge and integrate the currently recommended techniques and strategies. The aim of these guidelines is to guarantee an optimal care of patients undergoing anesthesiological procedures and serve as an orientation and decision aid for users.

Purpose of the Study: The i-gel is a new single-use, noninflatable supraglottic airway for use in anesthesia during spontaneous or intermit tent positive pressure ventilation (1). Its wider and shorter stem suggest that it may be an ideal conduit for intubation using a fibrescope or blindly. A size 4 i-gel has a channel length of 192 mm and an internal diameter of 12.3 mm and will accept a 6.5-7.0-mm cof fed trachel tube. Materials and methods: Af ter approval of our IRB and writ ten informed consent was obtained, in 56 patients (ASA 1-3), undergoing minor routine gynaecologic surgery, standardised anesthesia was induced (Remifentanil and Propofol). A size 4 i-gel was inserted in all. Af ter insertion, the position of both devices was controlled using a fiberoptic bronchoscope (FOS) (4=only vocal cords visible; 3=vocal cords plus posterior epiglot tis; 2=vocal cords plus anterior epiglot tis; 1=vocal cords not visible but functions adequately; 0=vocal cords not visible and functions inadequately) and af ter suf ficient ventilation the patient were relaxation with 0.6 mg kg rocuronium. All patients were randomly allocated to an intubation at tempt via the i-gel device using either an ID 6.5 mm silicon’s Portex (PT-group) or an 6.5 mm Mallinckrodt ETT (MT-group) made of conventional clear polyvinylchloride (PVC). Both ETTs were inserted blindly by a single experienced anesthesiologist. In 20 patients with Portex ETT and in the other 29 patients, the Malinckrodt ETT was inserted. Failure rate and time to successful intubation were recoded. Results: Fiberoptic control of the position of the devices was comparable in both groups. In the PT-group, intubation was successful in 17 patients (FOS 4-8patients, FOS 3-8 patients, FOS1-1) and failed in 6 cases (FOS4-2, FOS3-1, FOS2-1 and FOS1-1). In MT-Group successful intubation was performed in 10 patients (FOS 4-3, FOS 3-3, FOS 2-1 and FOS 1-3) and intubation failed in 23 patients (FOS4-13, FOS3-3, FOS2-1 and FOS1-3). Successful intubation was significant higher in PT group (P< 0,001). Time to intubation with Portex ETT and with Mallinckrodt ETT was (mean ± standard deviation) 11±9 seconds and 14±8 seconds, respectively. Conclusions: The successful intubation with ETT via i-gel is not depended from fibreoptic score. Significantly higher failed rate sagest, that the i-gel is not suitable for intubation blindly with conventional PVC ETTs. References: Levitan et al.: Anaesthesia 2005; 60:1022-6

1University Hospital Schleswig-Holstein, Campus Kiel, Dept of Anaesthesiology & Intensive Care, Kiel, Germany, 2Hospital Links der Weser, Dept of Anaesthesiology & Intensive Care, Bremen, Germany, 3Sana Clinics Ost-Holstein, Dept of Anaesthesiology & Intensive Care, Eutin, Germany

Background. Recently, indirect videolaryngoscopes have become increasingly important devices in difficult airway management. The aim of the present study was to investigate laryngoscopic view and intubation success using the new C-MAC* D-Blade in comparison to the established GlideScope* videolaryngoscope and conventional direct laryngoscopy in a randomized controlled trial.Methods. Ninety-six adult patients with expected difficult airways undergoing elective ear, nose and throat surgery (ENT) requiring general anesthesia were investigated. Repeated laryngoscopy was performed using a conventional direct Macintosh laryngoscope (DL), C-MAC D-Blade (DB) and GlideScope (GS) in a randomized sequence before patients were intubated with the last device used.Results. Both videolaryngoscopes showed significantly better C/L (Cormack-Lehane) classes than DL. Insufficient laryngoscopic view, defined as C/L >= III, was experienced in 18 patients (19.2%) with DL, in two patients with GS (2.1%) and in none with DB (0%). Time to best achievable laryngoscopic view did not differ between devices. Intubation time was significantly longer with both videolaryngoscopes (Median [Range] DB: 18 [8-33] s, and GS: 19 [9-34] s) than with DL (11 [5-26] s). However, intubation success was 100% for both DB and GS, whereas four patients could not be intubated using conventional direct laryngoscopy.Conclusion. Compared to direct Macintosh laryngoscopy, both C-MAC* D-Blade and GlideScope* comparably resulted in an improved view of the glottic opening with successful tracheal intubation in all patients. (Minerva Anestesiol 2013;79:121-9)

Die endotracheale Intubation in einer Notfallsituation stellt die anspruchsvollste Aufgabe für den präklinisch tätigen Notarzt im Bereich der Atemwegssicherung dar. Insbesondere bei äußerlichen Patientenmerkmalen oder Einsatzbedingungen, die das Vorhandensein eines schwierigen Atemweges nahelegen, kann die Videolaryngoskopie zum Einsatz kommen mit der Möglichkeit, die Visualisierung des Atemweges zu optimieren und damit den Intubationserfolg sowie die Patientensicherheit zu erhöhen. Dabei erscheint für den präklinischen Einsatz unter erschwerten Intubationsbedingungen die Verwendung macintoshbasierter Videolaryngoskope besonders sinnvoll. Für die wenigen Einzelfälle, in denen ein macintoshbasiertes Videolaryngoskop aus anatomischen Gründen keine ausreichende Glottisvisualisierung ermöglicht, bietet die Möglichkeit zum Umstieg auf ein stärker gekrümmtes Spatelblatt innerhalb desselben Videolaryngoskopsystems ohne größeren Zeitverlust einen zusätzlichen Vorteil.

We enrolled 114 patients, aged 65-83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy.

The recently introduced C-MAC® dBlade (Karl Storz, Tuttlingen, Germany) is a new videolaryngoscope blade that adds to the existing C-MAC system. The aim of the present study was to compare for the first time the C-MAC® dBlade with the GlideScope videolaryngoscope, and conventional direct laryngoscopy during routine induction of anesthesia. After approval of the institutional review board and written informed consent, 33 patients (ASA I-III) of either sex (24 male) scheduled for routine surgery under general anesthesia, in whom tracheal intubation was mandatory (mean±SD [range] age 61±16 [18-85], weight 85±17 [52-144]), were randomly assigned in a crossover design to direct laryngoscopy with a Macintosh blade (DL group), to videolaryngoscopy with the GlideScope (GS group), or to videolaryngoscopy with the C-MAC dBlade (CM group). With DL, GS, and CM, a Cormack-Lehane class (C/L) 1 view of the glottis was seen in 11, 28, and 30 patients, class 2a view in 10, 4, and 2, class 2b in 5, 1, and 1, class 3 in 6, 0, and 0, and class IV in 1, 0, 0 patients, respectively. In those patients with difficult conventional laryngoscopy (C/L III and IV; n=7), view improved with GS and CM to C/L I in 3 and 5 patients, and to C/L IIa in 4 and 2 patients, respectively. For every patient, the median time taken until optimal visualization of the glottis in the DL, GS, and CM groups was 13 sec (range, 4-27 sec), 11 sec (range, 7-18 sec), and 10 sec (range, 6-24 sec), respectively. The median time taken for tracheal intubation in the DL, GS, and CM groups was 9 sec (range, 5-17 sec; n=11), 17 sec (range, 9-29 sec; n=11), and 14 sec (range, 8-29 sec; n=10), respectively. Our preliminary data suggest that both C-MAC dBlade and GlideScope showed comparable visualization of the glottis and intubation success, but improved visualization of the glottis compared with conventional laryngoscopy.

Summary We enrolled 114 patients, aged 65–83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy.

The term C-MAC Miller is confusing. I had read this over several times thinking that Storz had in fact produced a C-Miller blade. Perhaps the authors would consider abbreviating this as C-MAC/MT (for Miller technique) so that the Miller blade design is not so strongly suggested. We greatly appreciate this reviewers’ comment, since we were not aware of the current description being a basis for misinterpretation. Accordingly, we changed the abbreviation as suggested by the reviewer to C-MAC/SBT (SBT for “straight blade technique”). “no optimal glottic view with DL” is awkward phrasing. Thank you for this advice. We chanced the wording to “suboptimal”. “impeded glottic view”-consider “suboptimal” or Cormack-Lehane>1 Thank you for this advice. We chanced the wording to “suboptimal”. Methods include Results (eg age, gender, weight) According to the reviewers’ advice we have moved patient data to the results section.

Introduction: Management of the unexpected difficult airway poses still one of the most important challenges to anaesthesiologists. Recently, videolaryngoscopes have gained increasing interest especially for this purpose. In our study we investigated whether the use of the C-MAC videolaryngoscope blade 4 using the straight-blade-technique, described by Miller,1Miller R.A. A new laryngoscope.Anesthesiology. 1941; 2: 317-320Crossref Google Scholar may improve laryngoscopic view compared to conventional laryngoscopy without uploading the epiglottis. Material and methods: From January to March 2010, 205 consecutive patients (ASA classification 1–3) underwent elective minor surgery requiring general anaesthesia and endotracheal intubation. Direct laryngoscopy was performed using a Macintosh blade 3 or 4, as appropriate (DL). If conventional laryngoscopy resulted in glottic view classes III or IV according to Cormack and Lehane, modified by Yentis and Lee (CL),2Yentis Lee Anaesthesia. 1996; 53: 1041-1044Crossref Scopus (212) Google Scholar patients underwent additional laryngoscopy with the C-MAC videolaryngoscope blade 4 combined with straight-blade-technique (C-MAC4). Time from touching the device until achievement of the best laryngoscopic view was also recorded. Results: In fourteen patients of either gender (10 male), aged (median [range]) 64 [33–80] years, weighing 84 [70–101] kg (BMI 29 [24–40] kg/m2) conventional laryngoscopic view resulted in CL III (n = 11) and CL IV (n = 3). Subsequent videolaryngoscopy enhanced glottic view; in 11 out of 14 patients that showed CL ≥ III with the DL, the use of C-MAC4 with straight-blade-technique improved laryngoscopic view. Comparing C-MAC4 to DL CL view improved by 1 class in 1 patient, 2 in 5, 3 in 4 and 4 classes in 1 patient, respectively. The median (range) time from touching the device to best laryngoscopic view was 15 s (8–25 s) with DL, and 14 s (4–33 s) with C-MAC4, respectively. Conclusion: The C-MAC video laryngoscope blade 4 combined with the use of straight-blade-technique as described by Miller may be a helpful rescue device for management of the unexpected difficult airway.

Study Objectives: Emergency department (ED) crowding appears to contribute to ED medication errors.Our prior analysis suggested that error frequency increases disproportionately with crowding.To clarify more precisely the relation between crowding and error occurrence, we measured the association between medication errors and crowding in the ED over discrete time intervals while controlling for the number of charts reviewed and the presence of ambulance diversion status.We hypothesized that errors would occur significantly more frequently as crowding increased, even after controlling for higher patient volumes.Methods: We performed a prospective, observational study in a large, community hospital ED from May to October of 2009.Our ED has full-time pharmacists who review orders of patients to help identify errors prior to their causing harm.Research volunteers shadowed our ED pharmacists over discrete 4-hour time periods during their reviews of orders on patients in the ED.The total numbers of charts reviewed and errors identified were documented along with details for each error type, severity, and category.We then measured the correlation between error rate (number of errors divided by total number of charts reviewed) and ED occupancy rate while controlling for diversion status during the observational period.We estimated a sample size requirement of at least 45 errors identified to allow detection of an effect size of 0.6 based on our historical data.Results: A total of 1171 charts were reviewed during 324 hours of error surveillance, in which 87 errors were identified.Errors occurred throughout the spectrum of care and included incorrect doses, routes, and medications as well as medication duplications and delays in therapy.Median error rate per 4-hour block was 5.8% of charts reviewed (IQR 0-13).No significant change was seen with ED occupancy rate (Spearman's rho ϭ -.08, pϭ.49).Median error rate during times on ambulance diversion was almost twice as large (11%, IQR 0-17), but this rate did not reach statistical significance in univariate or multivariate analysis.Conclusion: Error frequency appears to remain relatively constant across the range of crowding in our ED when controlling for patient volume via the quantity of orders reviewed.Error quantity therefore increases with crowding, but not at a rate greater than the expected baseline error rate that occurs in uncrowded conditions.These findings suggest that crowding will increase error quantity in a linear fashion.