The effect of fresh gas flow during induction of anaesthesia on sevoflurane usage: a quality improvement study.

Reducing fresh gas flow during inhalational anaesthesia results in cost savings and decreases environmental impact. We are interested in the influence of fresh gas flow on the early (induction) phase of overall fresh gas flow and vapour consumption. This stage is often excluded in studies of fresh gas flow. Data were collected from 3199 sevoflurane anaesthetics over an 11-month period in four operating theatres. We determined fresh gas flow at different stages of anaesthesia, and developed an explanatory model for the influence of the 'induction' period. Following a three-month collection of baseline data we emphasised the importance of the early phase to our department repeatedly over a two-week period. We explored the relationship between fresh gas flow and total vapour usage, and used a simple mathematical model to explore the effect of changes in the fresh gas flow and duration of the 'induction' phase. Mean fresh gas flow was 1.15 l.min-1 in the baseline period and 0.91 l.min-1 in the two months following our educational effort (p = 0.0005). In the following six months, mean fresh gas flow was 1.17 l.min-1 (p = 0.7726 compared with baseline). These results were driven by changes in both fresh gas flow and duration of the initial high-flow period. We found some correlation (R2  = 0.85) between overall fresh gas flow and vapour consumption; a 1 l.min-1 increase in fresh gas flow consumes an additional 18 ml.hr-1 of liquid sevoflurane. This preliminary study demonstrates that an episode of high fresh gas flow at the start of anaesthesia has a large and modifiable effect on overall fresh gas flow and vapour consumption. We also confirmed the linear relationship between fresh gas flow and vapour usage.

A ten-year audit of fresh gas flows in a New Zealand hospital: the influence of the introduction of automated agent delivery and comparisons with other hospitals.

Reducing fresh gas flow (FGF) rates with volatile anaesthetics reduces waste, with positive financial and environmental consequences. We have audited FGF since 2001 by analysis of data collected from anaesthetic machines. We recently introduced Aisys(®) (GE Healthcare, Madison, WI, USA) machines that allow automated control of end-tidal levels of volatile anaesthetics. In 2009 the mean FGF was 1.27 l/minute, which was lower than 2001 (2.05 l/minute) and 2006 (1.43 l/minute) and similar to two other New Zealand hospitals. Following introduction of the Aisys(®), mean FGF initially increased to 1.5 l/minute, but fell to 1.09 l/minute over the following 12 months. Median FGF showed a similar pattern and is now <600 ml/minute. Since introduction of the Aisys(®) workstation the proportion of time with flow rates >4 l/minute has increased. The proportion of time spent in automated delivery mode has increased from 35% to 63%. Users valued the workload reduction with end-tidal control. Our findings suggest that in daily practice, with a wide range of practitioners at different levels of training and a broad patient mix, mean flow rates of around 1.3 l/minute with median flows in the range 0.5 to 1.0 l/minute are achievable targets.

Effective size of a wild salmonid population is greatly reduced by hatchery supplementation.

Many declining and commercially important populations are supplemented with captive-born individuals that are intentionally released into the wild. These supplementation programs often create large numbers of offspring from relatively few breeding adults, which can have substantial population-level effects. We examined the genetic effects of supplementation on a wild population of steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, by matching 12 run-years of hatchery steelhead back to their broodstock parents. We show that the effective number of breeders producing the hatchery fish (broodstock parents; N(b)) was quite small (harmonic mean N(b)=25 fish per brood-year vs 373 for wild fish), and was exacerbated by a high variance in broodstock reproductive success among individuals within years. The low N(b) caused hatchery fish to have decreased allelic richness, increased average relatedness, more loci in linkage disequilibrium and substantial levels of genetic drift in comparison with their wild-born counterparts. We also documented a substantial Ryman-Laikre effect whereby the additional hatchery fish doubled the total number of adult fish on the spawning grounds each year, but cut the effective population size of the total population (wild and hatchery fish combined) by nearly two-thirds. We further demonstrate that the Ryman-Laikre effect is most severe in this population when (1) >10% of fish allowed onto spawning grounds are from hatcheries and (2) the hatchery fish have high reproductive success in the wild. These results emphasize the trade-offs that arise when supplementation programs attempt to balance disparate goals (increasing production while maintaining genetic diversity and fitness).

A New Zealand based cohort study of anaesthetic trainees' career outcomes compared with previously expressed intentions.

Predicting workforce requirements is a difficult but necessary part of health resource planning. A 'snapshot' workforce survey undertaken in 2002 examined issues that New Zealand anaesthesia trainees expected would influence their choice of future workplace. We have restudied the same cohort to see if that workforce survey was a good predictor of outcome. Seventy (51%) of 138 surveys were completed in 2009 compared with 100 (80%) of 138 in the 2002 survey. Eighty percent of the 2002 respondents planned consultant positions in New Zealand. We found 64% of respondents were working in New Zealand (P < 0.01). We found that family ties were an important influence on the choice of country of residence for 80% of New Zealand based respondents but only 40% of those living outside New Zealand agreed or strongly agreed with this statement (P < 0.01). Remuneration influenced country of residence for 76% of those living outside New Zealand but was important for only 2% of those resident in New Zealand (P < 0.01). Salaries in New Zealand were predominantly between NZ$150,000 and $200,000 while those overseas received between NZ$300,000 and $400,000. Of those that are resident in New Zealand, 84% had studied in a New Zealand medical school compared with 52% of those currently working overseas (P < 0.01). Our study shows that stated career intentions in a group do not predict the actual group outcomes. We suggest that 'snapshot' studies examining workforce intentions are of little value for workforce planning. However we believe an ongoing program matching career aspirations against career outcomes would be a useful tool in workforce planning.

The development of a system to guide volatile anaesthetic administration.

We have developed and deployed within our operating rooms a system which provides real-time estimates of effect-site levels of inhalational anaesthetic agents along with forward predictions of end-tidal and effect-site concentrations. The initial aim of this project was to provide users of inhalational agents with tools similar to those available in target-controlled infusion systems. This paper describes the development and implementation of the system and outlines evaluation and uses of the system. The prototype was developed by combining a locally developed data logging and trend display system with a model of uptake developed as a teaching tool in 1982. This uptake model performs as well as contemporary models of propofol uptake and distribution. Following initial evaluation, the system has been deployed in over half our operating rooms and uses data gathered from the Datex/GE Anaesthesia Delivery Unit anaesthetic machines. We have conducted a number of studies of the system itself explored aspects of the underlying models, and used the system to investigate effect-site guided anesthesia and as a tool for data collection in other studies. The system has been well accepted locally and has been shown to facilitate faster changes in inhalational levels. We have also seen a significant decrease in fresh gas flow rates over recent years and attribute this in part to the predictive system, which simplifies the task of determining the appropriate combination of gas flow and vapour dial setting. The system also provides a useful platform for a range of research projects.

Mortality of one-week-old chickens during naturally occurring Marek's disease virus infection.

Marek's disease (MD) is a disease of chickens that occurs worldwide and has serious economic consequences. MD can present as one of several forms, with the most commonly occurring forms being the lymphoproliferative diseases. Under experimental conditions, an early mortality syndrome has been recognized following infection by some but not all strains of MD virus (MDV). This is the first report of a confirmed case of mortality due to naturally occurring MDV infection in 1-week-old, nonvaccinated, chickens. Necrotizing lesions were observed in the bursa of Fabricius, lung, duodenum, jejunum, and proventriculus, and large intranuclear inclusion bodies were a striking feature in tissues with lesions in all birds. Immunohistochemical staining for the pp38 protein of MDV revealed abundant pp38 antigen in the affected tissues, confirming the presence of MDV within the lesions. PCR yielded an amplicon with 97% homology to the meq gene of MDV. No evidence of co-infection by either of the immunosuppressive agents chicken anemia virus and infectious bursal disease virus was detected.

Neoplasia and granulomas surrounding microchip transponders in Damaraland mole rats (Cryptomys damarensis).

Damaraland mole rats (Cryptomys damarensis) are among the longest-living rodents, with a maximum longevity of approximately 16 years. As one of the few mammals termed eusocial, these animals have been used in behavioral, genetic, metabolic, and physiologic research at the University of Connecticut since 1997. For individual identification at 3 to 4 months of age, mole rats were subcutaneously implanted with microchip transponders (11 mm in length) in the dorsal cervical region. In 2007, 2 of the 90 implanted adults, 10-year-old and 9-year-old females, developed subcutaneous masses at the site of the implant. Histopathological and immunohistochemical examinations revealed amelanotic melanoma and fibrosarcoma, respectively, with metastasis of the amelanotic melanoma. In 2008, a total of 3 adult males were castrated as part of a sex behavior study; 3 months later, all 3 castrated males developed subcutaneous masses around their implants, whereas none of the noncastrated males had masses. After an additional 9 months, these masses were found to be granulomas. To the authors' knowledge, this is the first report of neoplasia in this species. Both the tumors and the granulomas surrounded the microchip transponder.

The effect of predictive display on the control of step changes in effect site sevoflurane levels.

Graphical displays of past and future levels of drugs may be a useful adjunct to manual dosing. We have previously found that a display of predicted future values speeds step changes in end-tidal sevoflurane. In this study anaesthetists made step changes of 0.3% in effect site sevoflurane, with and without the display and as increases and decreases. We analysed 91 changes. When the predictive display was present, users made larger vaporiser dial changes of 3.9% vs 3.1% (95% CI for the difference -1.3% to -0.01%, p = 0.046) reflected in larger end-tidal changes (95% CI for the difference -0.009 vol% to -0.34 vol%, p = 0.06). There was no difference in the speed of change (220 vs 227 s (95% CI for the difference -51 to 32 s)), or in the accuracy of the change. In this study the predictive display influenced the magnitude of the step changes made by anaesthetists but did not affect the speed or overall accuracy of the change.

The use of epidural analgesia in a New Zealand tertiary hospital before and after publication of the MASTER study.

We audited the total number of perioperative epidural techniques performed at Christchurch Hospital, New Zealand, for three years, before and after The Lancet published the MASTER Anaesthesia Trial in 2002. We also looked specifically at the number of epidural anaesthetic and analgesic techniques performed in combination with general anaesthesia for colonic surgery over the same period. In both cases we found a statistically significant fall in epidural rate in the years after the publication (P < 0.001). A subsequent survey of local specialist anaesthetists, who have worked throughout this period, revealed the majority (75%) were knowingly performing fewer epidural techniques and that the findings of the MASTER Anaesthesia Trial had influenced their decisions.

Rapid preclinical detection of sheeppox virus by a real-time PCR assay.

Sheeppox virus (SPPV) is a member of the Capripoxvirus (CaPV) genus of the Poxviridae family. Members of this genus, which also include goatpox and lumpy skin disease viruses, cause economically significant disease in sheep, goats, and cattle. A rapid diagnostic assay for CaPV would be useful for disease surveillance as well as for detection of CaPV in clinical samples and for outbreak management. Here we describe a fluorogenic probe hydrolysis (TaqMan) PCR assay designed for rapid detection of CaPV and tested on sheep experimentally infected with a virulent strain of SPPV. This assay can detect SPPV in buffy coats, nasal swabs, oral swabs, scabs, and skin lesions as well as in lung and lymph nodes collected at necropsy. This single-tube diagnostic assay can be performed in 2 h or less and can detect viral DNA in preclinical, clinical, and postmortem samples.

Extraintestinal pathogenic Escherichia coli-induced acute necrotizing pneumonia in cats.

Extraintestinal pathogenic Escherichia coli (ExPEC) are pathogens involved in several disease conditions, ranging from urinary tract infection to meningitis in humans and animals. They comprise epidemiologically and phylogenetically distinct strains, affecting most species and involving any organ or anatomical site. Here, we report fatal cases of necrotizing pneumonia in cats. Over a 1-week period, 13 cats from an animal shelter in Stamford, Connecticut were presented for necropsy. All had a clinical history of acute respiratory disease. The gross and microscopic findings for all the cats were consistent. Escherichia coli was uniformly isolated from the lungs of all the tested cats. All the isolates were haemolytic, genetically related as determined by enterobacterial repetitive intergenic consensus PCR, and harboured genes encoding for cytotoxic necrotizing factor-1 and fimbriae and adhesions that are characteristic of ExPEC, implying a point source clonal outbreak. As cats are common household pets, this report raises concerns regarding zoonotic potential (in either direction) for these ExPEC strains.

Sheeppox virus kelch-like gene SPPV-019 affects virus virulence.

Sheeppox virus (SPPV), a member of the Capripoxvirus genus of the Poxviridae, is the etiologic agent of a significant disease of sheep in the developing world. Genomic analysis of pathogenic and vaccine capripoxviruses identified genes with potential roles in virulence and host range, including three genes with similarity to kelch-like genes of other poxviruses and eukaryotes. Here, a mutant SPPV with a deletion in the SPPV-019 kelch-like gene, DeltaKLP, was derived from the pathogenic strain SPPV-SA. DeltaKLP exhibited in vitro growth characteristics similar to those of SPPV-SA and revertant virus (RvKLP). DeltaKLP-infected cells exhibited a reduction in Ca(2+)-independent cell adhesion, suggesting that SPPV-019 may modulate cellular adhesion. When inoculated in sheep by the intranasal or intradermal routes, DeltaKLP was markedly attenuated, since all DeltaKLP-infected lambs survived infection. In contrast, SPPV-SA and RvKLP induced mortality approaching 100%. Lambs inoculated with DeltaKLP exhibited marked reduction or delay in fever response, gross lesions, viremia, and virus shedding compared to parental and revertant viruses. Together, these findings indicate that SPPV-019 is a significant SPPV virulence determinant in sheep.

Fluorescent antibody test for rapid detection of West Nile virus antigen in avian tissues.

An indirect fluorescent antibody test (IFA) was developed to detect West Nile virus (WNV) antigens in tissues from avian species. The test samples used in the study consisted of 100 sets of tissues from dead crows that had been collected during the 2001 surveillance in Connecticut. The test tissues were punctured with a fine point Dacron cotton-tipped applicator and smeared in duplicate on 10-well diagnostic printed glass slides. Among several fixatives tested, 4% paraformaldehyde was the best. Reagent calibration for the IFA test was done in WNV-infected Vero cells and control uninfected Vero cells. Optimized antibody and fluorescent conjugate concentrations were then applied for the detection of WNV antigen on fixed tissue impression smears. Several tissues, including brain, heart, liver, kidney, and spleen were tested by the IFA test. The brain and heart seemed to be unsuitable for the test because of excessive background. Both virus isolation and reverse transcription-polymerase chain reaction (RT-PCR) were used for validation, with the latter technique having a higher sensitivity. Therefore, IFA results were compared with RT-PCR results. The diagnostic sensitivity was 96.8% for liver, 96.4% for kidney, and 100% for spleen. The diagnostic specificity was 69% for liver, 95.3% for kidney and 95.8 for spleen. The IFA test performed best with spleen and kidney. The IFA test described here is a useful, practical, and rapid test for screening for WNV.

An evaluation of the GlideScope, a new video laryngoscope for difficult airways: a manikin study.

BACKGROUND AND OBJECTIVES: The GlideScope is a new video laryngoscope. The aim of our study was to assess its use compared to a Macintosh blade in airway scenarios on the Airman airway simulator. The scenarios were: 'normal' or resting state of the manikin, pharyngeal obstruction, cervical rigidity and tongue oedema. METHODS: Thirty anaesthetists from the Christchurch Anaesthetic Department attempted to pass a bougie or stylet through the vocal cords of the manikin with a size 3 Macintosh blade, then the GlideScope. View at laryngoscopy, ease of 'intubation' and whether they thought the GlideScope would be useful in clinical practice were recorded. RESULTS: Forty three percent (P = 0.02) found an improved view with the GlideScope in the pharyngeal obstruction scenario. In the other scenarios there was no significant difference in view. Reportage of ease of intubation showed no statistical difference in any scenarios. However, 93% of anaesthetists considered having the GlideScope would be useful if faced clinically with one or more of the studied scenarios. CONCLUSIONS: The GlideScope improved the view in one of three difficult airway situations when used by anaesthetists with no formal training in its use. No single airway device offers a solution to all scenarios, however, we consider that the GlideScope is a useful addition to the range of difficult airway devices available.

Mutation of E1 glycoprotein of classical swine fever virus affects viral virulence in swine.

Transposon linker insertion mutagenesis of a full-length infectious clone (IC) (pBIC) of the pathogenic classical swine fever virus (CSFV) strain Brescia was used to identify genetic determinants of CSFV virulence and host range. Here, we characterize a virus mutant, RB-C22v, possessing a 19-residue insertion at the carboxyl terminus of E1 glycoprotein. Although RB-C22v exhibited normal growth characteristics in primary porcine macrophage cell cultures, the major target cell of CSFV in vivo, it was markedly attenuated in swine. All RB-C22v-infected pigs survived infection remaining clinically normal in contrast to the 100% mortality observed for BICv-infected animals. Comparative pathogenesis studies demonstrated a delay in RB-C22v spread to, and decreased replication in the tonsils, a 10(2) to 10(7) log10 reduction in virus titers in lymphoid tissues and blood, and an overall delay in generalization of infection relative to BICv. Notably, RB-C22v-infected animals were protected from clinical disease when challenged with pathogenic BICv at 3, 5, 7, and 21 days post-RB-C22v inoculation. Viremia, viral replication in tissues, and oronasal shedding were reduced in animals challenged at 7 and 21 DPI. Notably BICv-specific RNA was not detected in tonsils of challenged animals. These results indicate that a carboxyl-terminal domain of E1 glycoprotein affects virulence of CSFV in swine, and they demonstrate that mutation of this domain provides the basis for a rationally designed and efficacious live-attenuated CSF vaccine.

The E2 glycoprotein of classical swine fever virus is a virulence determinant in swine.

To identify genetic determinants of classical swine fever virus (CSFV) virulence and host range, chimeras of the highly pathogenic Brescia strain and the attenuated vaccine strain CS were constructed and evaluated for viral virulence in swine. Upon initial screening, only chimeras 138.8v and 337.14v, the only chimeras containing the E2 glycoprotein of CS, were attenuated in swine despite exhibiting unaltered growth characteristics in primary porcine macrophage cell cultures. Additional viral chimeras were constructed to confirm the role of E2 in virulence. Chimeric virus 319.1v, which contained only the CS E2 glycoprotein in the Brescia background, was markedly attenuated in pigs, exhibiting significantly decreased virus replication in tonsils, a transient viremia, limited generalization of infection, and decreased virus shedding. Chimeras encoding all Brescia structural proteins in a CS genetic background remained attenuated, indicating that additional mutations outside the structural region are important for CS vaccine virus attenuation. These results demonstrate that CS E2 alone is sufficient for attenuating Brescia, indicating a significant role for the CSFV E2 glycoprotein in swine virulence.

Preclinical diagnosis of African swine fever in contact-exposed swine by a real-time PCR assay.

A fluorogenic probe hydrolysis (TaqMan) PCR assay for African swine fever virus (ASFV) was developed and evaluated in experimentally infected swine. This sensitive and specific one-step single-tube assay, which can be performed in 2 h or less, detected viral DNA in tonsil scraping samples 2 to 4 days prior to onset of clinical disease. Thus, the assay would have application for preclinical diagnosis of African swine fever and surveillance and/or emergency management of a disease outbreak.

A breathing circuit disconnection detected by anesthetic agent monitoring.

PURPOSE: To describe a case involving a spontaneously breathing patient where a circuit disconnection was detected by a change in monitored anesthetic agent parameters. CLINICAL FEATURES: A patient undergoing shoulder surgery was breathing spontaneously from a circle type anesthesia circuit via a laryngeal mask. A disconnection occurred between the heat and moisture exchanger (HME) and the circle system's Y-piece. As the gas sampling port was integrated into the HME a near normal pattern of CO2 continued to be displayed. The disconnection was noted because of a change in the graphical display of the volatile agent concentration. CONCLUSIONS: Anesthetic circuit disconnection can be difficult to detect, especially in the spontaneously breathing patient. Capnometry may not detect a disconnection on the machine side of the gas sampling port. Changes in oxygen and volatile agent concentrations may provide an early indication of these types of disconnection.

The West Nile virus: its recent emergence in North America.

West Nile fever emerged in New York in the summer of 1999 when seven people, several horses and thousands of wild birds died. It was soon established that the human disease and the mortality of birds were related. Continued surveillance detected West Nile virus in mosquitoes, birds, horses, small mammals, bats and humans, and has shown its spread to several northeastern states. These events confirm the establishment of West Nile virus endemically in the United States.

Development of a multiplex PCR for the detection of Haplosporidium nelsoni, Haplosporidium costale and Perkinsus marinus in the eastern oyster (Crassostrea virginica, Gmelin, 1971).

Haplosporidium costale (SSO), Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo) have caused oyster mortality on the North American east coast since the 1950s. Currently, the monitoring of oyster populations for these pathogens depends on histopathology for H. nelsoni, H. costale and the Ray/Mackin assay for P. marinus. In this study we describe the development and optimization of a multiplex polymerase chain reaction (MPCR) for the detection of H. nelsoni, H. costale and P. marinus. In addition, we determine its specificity and sensitivity. The MPCR clearly detects and differentiates the protozoan pathogens. There was no cross-reactivity between these species. The MPCR was able to detect DNA from H. nelsoni as low as 10 fg and P. marinus and H. costale as low as 1 pg. The MPCR allows for the detection of H. nelsoni, H. costale and P. marinus in a single PCR reaction.