Hypotension during induction of anaesthesia is neither a reliable nor a useful quality measure for comparison of anaesthetists' performance.

BACKGROUND: Identification of statistically reliable outcomes for comparison among anaesthetists is challenging. Time-weighted intraoperative mean arterial pressure <65 mm Hg (AUC 65 ) is associated with increased odds for myocardial damage. We explored retrospectively whether such hypotension before incision was statistically reliable for peer comparison. METHODS: We retrieved electronic data between 2006 and 2015 at a tertiary care, academic hospital in the USA for patients at risk for myocardial damage (inpatient after surgery, ASA physical status ≥III, ≥50 yr of age, and case duration ≥60 min). We determined the percentage of anaesthetists comparable based on caseload and case-mix. The AUC 65 was compared amongst anaesthetists supervising ≥100 cases involving at-risk patients during the last 12 months. RESULTS: Only 14.1% [95% confidence interval (CI) 13.6-14.5%] of cases involved patients who were 'at risk' during the 10 yr study period. A yearly average of 49 ( sd 6) anaesthetists supervised ≥100 cases of any type, of whom only 52% (95% CI 47.1-56.0%) supervised ≥100 cases involving at-risk patients. Thus, nearly half the anaesthetists would have been excluded from peer comparison. During the last 12 months, there were two outliers among 34 evaluable anaesthetists ( P <0.05, controlling for false discovery). However, their contribution to total hypotension amongst cases for all patients was small, because hypotension was widely distributed (e.g. 80% of hypotension attributable to 61.8% of anaesthetists, 95% CI 59.8-63.7%). There was no relationship between the AUC 65 and propofol induction dose. CONCLUSIONS: The AUC 65 of time-weighted pre-incision hypotension is not a suitable metric for comparing anaesthetists. There were few at-risk patients, half the anaesthetists were not evaluable because of their case-mix and caseload, and hypotension was widely distributed.

Hospitals with briefer than average lengths of stays for common surgical procedures do not have greater odds of either re-admission or use of short-term care facilities.

We considered whether senior hospital managers and department chairs need to be concerned that small reductions in average hospital length of stay (LOS) may be associated with greater rates of re-admission, use of home health care, and/or transfers to short-term care facilities. The 2013 United States Nationwide Readmissions Database was used to study surgical Diagnosis Related Groups (DRG) with 1) national median LOS ≥3 days and 2) ≥10 hospitals in the database that each had ≥100 discharges for the DRG. Dependent variables were considered individually: 1) re-admission within 30 days of discharge, 2) discharge disposition to home health care, and/or 3) discharge disposition of transfer to short-term care facility (i.e., inpatient rehabilitation hospital or skilled nursing facility). While controlling for DRG, each one-day decrease in hospital median LOS was associated with an odds of re-admission nationwide of 0.95 (95% confidence interval [CI] 0.92-0.99; P=0.012), odds of disposition upon discharge being home care of 0.95 (95% CI 0.83-1.10; P=0.64), and odds of transfer to short-term care facility of 0.68 (95% CI 0.54-0.85; P=0.0008). Results were insensitive to the addition of patient-specific data. In the USA, patients at hospitals with briefer median LOS across multiple common surgical procedures did not have a greater risk for either hospital re-admission within 30 days of discharge or transfer to an inpatient rehabilitation hospital or a skilled nursing facility. The generalisable implication is that, across many surgical procedures, DRG-based financial incentives to shorten hospital stays seem not to influence post-acute care decisions.

Mediated interruptions of anaesthesia providers using predictions of workload from anaesthesia information management system data.

Perioperative interruptions generated electronically from anaesthesia information management systems (AIMS) can provide useful feedback, but may adversely affect task performance if distractions occur at inopportune moments. Ideally such interruptions would occur only at times when their impact would be minimal. In this study of AIMS data, we evaluated the times of comments, drugs, fluids and periodic assessments (e.g. electrocardiogram diagnosis and train-of-four) to develop recommendations for the timing of interruptions during the intraoperative period. The 39,707 cases studied were divided into intervals between: 1) enter operating room; 2) induction; 3) intubation; 4) surgical incision; and 5) end surgery. Five-minute intervals of no documentation were determined for each case. The offsets from the start of each interval when >50% of ongoing cases had completed initial documentation were calculated (MIN50). The primary endpoint for each interval was the percentage of all cases still ongoing at MIN50. Results were that the intervals from entering the operating room to induction and from induction to intubation were unsuitable for interruptions confirming prior observational studies of anaesthesia workload. At least 13 minutes after surgical incision was the most suitable time for interruptions with 92% of cases still ongoing. Timing was minimally affected by the type of anaesthesia, surgical facility, surgical service, prone positioning or scheduled case duration. The implication of our results is that for mediated interruptions, waiting at least 13 minutes after the start of surgery is appropriate. Although we used AIMS data, operating room information system data is also suitable.

Observational study of anaesthetists' fresh gas flow rates during anaesthesia with desflurane, isoflurane and sevoflurane.

Reducing excessive fresh gas flow rates (FGF) is an established and simple strategy to reduce the administration of volatile anaesthetic agents. We studied clinicians' FGF use to understand better why two previous clinical trials achieved significant reductions in FGF by using feedback to anaesthetists. Anaesthesia information management system data from a US academic medical centre were analysed retrospectively. One year of data starting from July 2008 had 11,170 cases. Fresh gas flow rates were measured each minute during cases. Anaesthetists were more likely to choose FGF of multiples of 1 l/minute and 0.5 l/minute than random. However the pattern was too inconsistent to be of economic or psychological importance and thus is not needed when describing a target FGF. Cumulative distributions of FGF were shifted to the left for desflurane and isoflurane compared to sevoflurane (i.e. cost comparisons among agents may need to use different target FGF). Variation in mean FGF among anaesthetists was small. Even if all anaesthetists had identical mean FGF, the standard deviation of FGF among cases would be reduced by less than 0.1 l/minute for all agents. Most of the achievable reductions in FGF were small reductions in FGF for the many cases with < 3 l/minute. These results show that departments choosing to use inexpensive automatic email feedback on FGF should target all anaesthetists and focus on variation in FGF among anaesthetists' cases.

[Allocating and scheduling operating room time]. / Zuweisung und Planung von Operationsraumkapazitäten Maximierung der Operationsraumeffizienz am Beispiel einer deutschen Universitätsklinik.

During the past decade many scientific advances have been made concerning the development of methodologies to maximize efficiency of surgical facilities through allocating and scheduling of operating rooms. In this article such a methodology is described. Using the analysis of historical data of surgical activity in a facility, future demand is predicted and planned. Part of the methodology includes principles and rules needed for the daily organization and operative management of surgical facilities. They are also derived from the same science and therefore the basis for rational and structured decision making. Medical aspects such as patient safety and free choice of day for surgery have higher priority than the economic goal of maximizing operating room efficiency.

Reducing family members' anxiety while waiting on the day of surgery: systematic review of studies and implications of HIPAA health information privacy rules.

STUDY OBJECTIVE: To investigate changes that most surgical suites will need to make in the process of giving reports to family members on the day of surgery by the compliance date (April 14, 2003) of the privacy regulations of the Health Insurance Portability and Accountability Act (HIPPA) of 1996. DESIGN: Systematic review of the medical literature on ways in which providing information to family members changes their anxiety. MEASUREMENTS: The endpoints of the controlled studies included Spielberger State Anxiety. The observational studies reported percentages of family members with a specific concern. MAIN RESULTS: An in-person progress report can reduce family members' anxiety, but this is not always. A personal approach is superior to providing pagers or a phone call. Observational studies suggest that family members want information specific to their relative, particularly if the case is running later than expected. Statistical methods exist to provide such an estimate of the time remaining in surgical cases. CONCLUSIONS: Surgical facilities should strive to provide in-person progress reports to family members while their relatives are undergoing surgery. To satisfy HIPAA regulations, the staff and physicians who talk to family members in the waiting room will need to determine first if the patient has agreed to the release of information. As hospital information systems are updated to assure that this process is HIPAA-compliant, facilities can also incorporate the relevant statistical methods.

A statistical analysis of weekday operating room anesthesia group staffing costs at nine independently managed surgical suites.

UNLABELLED: At many surgical suites, surgeons and patients schedule elective cases on whatever future workday they choose, resulting in there being no limit on the number of cases performed each day. Staff are then scheduled in the manner that satisfies the marketing guarantee to the surgeons, satisfies labor contracts, and minimizes staffing costs. We assessed weekday nurse anesthesia group staffing at nine such suites to determine whether statistical methods can identify staffing solutions whereby all the cases are covered but for which staffing costs are less than those obtained using the staffing plans implemented by anesthesia groups' managers. Two years of operating room information system case duration and staffing data were analyzed. First- and second-shift staffing was assessed using previously published algorithms. The statistical methods identified staffing solutions with significantly decreased labor costs than those currently being used at eight of the nine surgical suites. The statistical methods relied more on overtime than second-shift staffing. The incremental decrease in staffing costs achievable by using overlapping 8-, 10-, and 13-h shifts was negligible. Overall, we found that statistical methods can identify, for some surgical suites, staffing solutions whereby all the cases are covered but for which costs are significantly less and productivity significantly more than those obtained using the plans developed by the managers based on their experience and the data. IMPLICATIONS: Statistical methods can identify, for some surgical suites, anesthesia staffing solutions whereby all the cases are covered but for which labor costs are significantly less than those obtained using the staffing plans developed by the managers based on data and their experience.

Speed of recovery and side-effect profile of sevoflurane sedation compared with midazolam.

BACKGROUND: Sedation for surgical procedures performed with regional or local anesthesia has usually been achieved with intravenous medications, whereas the use of volatile anesthetics has been limited. The use of sevoflurane for sedation has been suggested because of its characteristics of nonpungency, rapid induction, and quick elimination. The purpose of this investigation was to assess the quality, recovery, and side effects of sevoflurane sedation compared with midazolam. METHODS: One hundred seventy-three patients undergoing surgery with local or regional anesthesia were enrolled in a multicenter, open-label, randomized investigation comparing sedation with sevoflurane versus midazolam. Sedation level was titrated to an Observer's Assessment of Alertness--Sedation score of 3 (responds slowly to voice). Recovery was assessed objectively by Observer's Assessment of Alertness--Sedation, Digit Symbol Substitution Test (DSST), and memory scores, and subjectively by visual analog scales. RESULTS: Significantly more patients in the sevoflurane group had to be converted to general anesthesia because of excessive movement (18 sevoflurane and 2 midazolam; P = 0.043). Of remaining patients, 141 were assessable for efficacy and recovery data (93 sevoflurane and 48 midazolam). Sevoflurane and midazolam produced dose-related sedation. Sevoflurane patients had higher DSST and memory scores during recovery. Seventy-six percent (sevoflurane) compared with 35% (midazolam) returned to baseline DSST at 30 min postoperatively (P < 0.05). More frequent excitement-disinhibition was observed with sevoflurane (15 [16%] vs. midazolam; P = 0.008). CONCLUSIONS: Sevoflurane for sedation produces faster recovery of cognitive function as measured by DSST and memory scores compared with midazolam. However, sevoflurane for sedation is complicated by a high incidence of intraoperative excitement.

Economic analysis of linking operating room scheduling and hospital material management information systems for just-in-time inventory control.

UNLABELLED: Operating room (OR) scheduling information systems can decrease perioperative labor costs. Material management information systems can decrease perioperative inventory costs. We used computer simulation to investigate whether using the OR schedule to trigger purchasing of perioperative supplies is likely to further decrease perioperative inventory costs, as compared with using sophisticated, stand-alone material management inventory control. Although we designed the simulations to favor financially linking the information systems, we found that this strategy would be expected to decrease inventory costs substantively only for items of high price ($1000 each) and volume (>1000 used each year). Because expensive items typically have different models and sizes, each of which is used by a hospital less often than this, for almost all items there will be no benefit to making daily adjustments to the order volume based on booked cases. We conclude that, in a hospital with a sophisticated material management information system, OR managers will probably achieve greater cost reductions from focusing on negotiating less expensive purchase prices for items than on trying to link the OR information system with the hospital's material management information system to achieve just-in-time inventory control. IMPLICATIONS: In a hospital with a sophisticated material management information system, operating room managers will probably achieve greater cost reductions from focusing on negotiating less expensive purchase prices for items than on trying to link the operating room information system with the hospital's material management information system to achieve just-in-time inventory control.

Preventing mediastinal shift after pneumonectomy does not abolish physiological compensation.

To determine the role of mediastinal shift after pneumonectomy (PNX) on compensatory responses, we performed right PNX in adult dogs and replaced the resected lung with a custom-shaped inflatable silicone prosthesis. Prosthesis was inflated (Inf) to prevent mediastinal shift, or deflated (Def), allowing mediastinal shift to occur. Thoracic, lung air, and tissue volumes were measured by computerized tomography scan. Lung diffusing capacities for carbon monoxide (DL(CO)) and its components, membrane diffusing capacity for carbon monoxide (Dm(CO)) and capillary blood volume (Vc), were measured at rest and during exercise by a rebreathing technique. In the Inf group, lung air volume was significantly smaller than in Def group; however, the lung became elongated and expanded by 20% via caudal displacement of the left hemidiaphragm. Consequently, rib cage volume was similar, but total thoracic volume was higher in the Inf group. Extravascular septal tissue volume was not different between groups. At a given pulmonary blood flow, DL(CO) and Dm(CO) were significantly lower in the Inf group, but Vc was similar. In one dog, delayed mediastinal shift occurred 9 mo after PNX; both lung volume and DL(CO) progressively increased over the subsequent 3 mo. We conclude that preventing mediastinal shift after PNX impairs recruitment of diffusing capacity but does not abolish expansion of the remaining lung or the compensatory increase in extravascular septal tissue volume.

High concentration versus incremental induction of anesthesia with sevoflurane in children: a comparison of induction times, vital signs, and complications.

STUDY OBJECTIVE: To compare sevoflurane induction times and complications in children during a high concentration, primed-circuit method and an incremental induction technique. DESIGN: Randomized, prospective open-label study. SETTING: Academic university hospital. PATIENTS: 40 unpremedicated ASA physical status I and II children age 4 months to 15 years undergoing elective surgical procedures with general anesthesia. INTERVENTIONS: Patients were randomized to one of two study groups. In the high concentration group, the anesthesia circuit was primed with 8% sevoflurane in a 2:1 nitrous oxide:oxygen (N2O:O2) mixture. Patients breathed this gas mixture spontaneously until loss of the eyelash reflex. In the incremental group, the face mask was applied and 1% sevoflurane in a 2:1 N2O:O2 mixture was administered. In this group, the sevoflurane concentration was increased by 1% every 2 to 3 breaths. Gas flows of 6 L/min were administered to both groups during the study period. Following loss of the eyelash reflex, the sevoflurane concentration was decreased to 5% until a depth of anesthesia sufficient to start an intravenous catheter was achieved. MEASUREMENTS AND MAIN RESULTS: Induction cooperation, induction time (face mask application to loss of the eyelash reflex), one-minute vital signs [blood pressure, heart rate, oxygen saturation via pulse oximetry (SpO2)], induction complications. Induction of anesthesia was faster in the high concentration group than in the incremental group (mean (SD) 42 (9) sec vs. 66 (12) sec, respectively; p < 0.001). Induction complications were minor and occurred with similar frequencies (4/20 patients vs. 3/20 patients). There were no significant intergroup heart rate, blood pressure, or SpO2 differences during induction. No patients required treatment for hypotension or bradycardia. CONCLUSIONS: In healthy pediatric patients undergoing mask induction of general anesthesia with sevoflurane, the induction time can be significantly shortened without an increase in the frequency of airway or vital sign complications using a high concentration, primed circuit technique compared with a conventional, incremental induction method.

In vivo assessment of changes in air and tissue volumes after pneumonectomy.

We examined the progression and topographical distribution of postpneumonectomy volume changes in immature foxhounds undergoing right pneumonectomy (R-Pnx, n = 5) or sham pneumonectomy (Sham, n = 6) at 2 mo of age and subsequently raised to maturity. Volumes of lung air (Vair) and tissue (Vti) were estimated by computerized tomography (CT) scan at 7, 22, and 52 wk after surgery at a transpulmonary pressure of 20 cmH2O. Estimates of Vti by CT scan included both septal tissue as well as nonseptal tissue (small- and medium-sized airways and blood vessels); these were compared with estimates of septal Vti by an acetylene rebreathing (Rb) method. We found significant correlations between these techniques (Vair(CT) = 0.83 Vair(Rb) + 275, R = 0.97; Vti(CT) = 1.62 Vti(Rb) - 30, R = 0.81). Extravascular septal Vti returned to normal 7 wk after R-Pnx and remained normal up to maturity. Nonseptal Vti remained significantly below normal. The greatest increase in Vti occurred in the midlung region just cephalad and caudal to the heart. After an early period of accelerated tissue growth after R-Pnx, the rate of septal tissue growth matched that of somatic growth, whereas nonseptal tissue growth lagged behind. Compensatory growth of the remaining left lung was not associated with selective alterations in thoracic development.

The safety and efficacy of oral transmucosal fentanyl citrate for preoperative sedation in young children.

Oral transmucosal fentanyl citrate (OTFC) is a labeled preoperative pediatric sedative. Doses greater than 15 micrograms/kg are associated with a high incidence of post-operative nausea and vomiting and occasional respiratory depression. We studied the safety and efficacy of OTFC in children 6 yr old and younger at a dose of 15 micrograms/kg. Nineteen patients undergoing surgery associated with postoperative pain were randomized to receive OTFC/intravenous (IV) saline or placebo lozenge/IV fentanyl. After 45 min, patients receiving OTFC became more sedated than the placebo group, but there were no differences in cooperation, apprehension, parental separation, or induction cooperation scores. Preoperatively, neither respiratory depression nor oxygen desaturation occurred. Nine of 10 OTFC patients developed mild pruritus, and three of 10 OTFC patients vomited preoperatively; neither complication occurred in the placebo group. (The high incidence of preoperative vomiting led to the termination of the protocol before the anticipated enrollment of 40 patients.) General anesthesia was induced via a mask, followed by a propofol infusion. Spo2 and respiratory rate were monitored, and sedation, apprehension, cooperation, ease of parental separation, and induction cooperation were scored. One OTFC patient developed rigidity during induction. Emergence and recovery were not delayed by OTFC despite a 50% incidence of postoperative vomiting. We do not recommend the use of OTFC in a 15 micrograms/kg dose as a routine preoperative sedative in children 6 yr old and younger.

Airway sealing pressures of the laryngeal mask airway in pediatric patients.

STUDY OBJECTIVES: To determine if the laryngeal mask airway (LMA) seal is maintained during surgery, to evaluate the safety of an LMA leak test, and to determine the time course of the increase in LMA cuff pressure in vivo in the presence of nitrous oxide (N2O). STUDY DESIGN: Descriptive clinical study. SETTING: University teaching hospital. PATIENTS: 78 ASA Physical Status I and II pediatric patients, aged 3 months to 17 years, undergoing general anesthesia with an LMA; 14 patients were studied on two occasions approximately 2 months apart. INTERVENTIONS: The airway pressure at which the LMA seal was broken (leak pressure) was determined immediately following insertion of the LMA and at the end of surgery. In 17 patients, the LMA cuff pressure was continuously measured during surgery, during which 67% N2O was administered. The mean duration of surgery was 29.5 minutes. MEASUREMENTS AND MAIN RESULTS: The LMA leak pressure was determined by closing the circuit popoff valve and recording the pressure at which gas was first heard to escape around the LMA at the mouth. The LMA cuff pressure was determined by connecting the check valve of the LMA pilot balloon to a sphygmomanometer. The elastance of the LMA was determined from the slopes of the regression lines of pressure versus volume for the various sized LMAs in vitro (Sizes 1-4) and in vivo (sizes 2 and 2 1/2). The initial LMA leak pressure was 25.9 cm H2O, and it increased to 31.2 cm H2O during surgery (p < 0.001). 146 leak tests were performed without causing gastric dilatation or LMA dislodgement. The mean LMA cuff pressure increased during surgery from 106.2 mmHg to 132.8 mmHg (p < 0.001), a pressure increase that corresponds to a volume increase of 1.4 ml. CONCLUSIONS: The LMA leak test can be safely performed. The airway seal provided by the LMA is well maintained during surgery. The increase in LMA cuff pressure during surgery in the presence of N2O is small and probably is not a cause for clinical concern. If positive pressure is to applied in the presence of an LMA, one should limit this pressure to below the LMA leak pressure so as to lower the risk of inflating the stomach with gas that may than leak around the LMA.

Sevoflurane versus halothane for general anesthesia in pediatric patients: a comparative study of vital signs, induction, and emergence.

STUDY OBJECTIVE: To compare vital signs and the speed of induction and emergence with sevoflurane versus halothane in pediatric patients. DESIGN: Prospective, randomized, open study. SETTING: Thomas Jefferson University Hospital. PATIENTS: 40 unpremedicated ASA Physical Status I and II children age 9 months to 16 years undergoing elective inpatient otorhinolaryngologic or orthopedic surgery. INTERVENTIONS: Standardized induction of anesthesia with sevoflurane (start: 1%, maximum: 7%) or halothane (start: 0.5%, maximum: 5%) in nitrous oxide/oxygen (N2O/O2). Intubation following vecuronium and 4 minutes of controlled ventilation with 2 minimum alveolar concentration (MAC) drug in O2; 1.5 MAC drug in N2O/O2 delivered for 20 minutes; then 0.75 MAC until the end of surgery. Fentanyl 1 mcg/kg was administered 15 minutes before the anticipated end of surgery, at which time anesthetics were stopped and mechanical ventilation continued until eye opening (emergence). MEASUREMENTS AND MAIN RESULTS: Blood pressure, heart rate (HR), oxygen saturation, end-tidal gas concentrations, and temperature were recorded. Induction and emergence times were measured to the nearest second. Induction (loss of eyelash reflex) was faster with sevoflurane (97 +/- 31 sec) than halothane (120 +/- 36 sec; p < 0.05), despite a lower inspired sevoflurane MAC. Emergence was faster with sevoflurane (9.9 +/- 2.9 min vs. 12.5 +/- 4.7 min; p < 0.05), despite a higher MAC multiple of end-tidal sevoflurane concentration at the end of surgery. Following intubation, HR (compared with the preinduction value in the operating room) was significantly higher in the halothane group (136.8% +/- 16.3% vs. 115.0% +/- 25.6%), as was mean arterial pressure (113.2% +/- 25.5% vs. 87.8% +/- 22.6%). This finding corresponded with a higher MAC multiple of end-tidal concentration in the sevoflurane group than in the halothane group. CONCLUSIONS: Induction of and emergence from anesthesia was faster with sevoflurane than halothane. Airway complications were low in both groups. Vital signs were more stable with sevoflurane during induction through intubation, and were comparable during maintenance. Sevoflurane is an excellent drug for inhalational induction in pediatric patients.