The Effect of a Surgery-Specific Cardiac Output–Guided Haemodynamic Algorithm on Outcomes in Patients Undergoing Pancreaticoduodenectomy in a High-Volume Centre: A Retrospective Comparative Study

In this retrospective observational study performed in a high-volume hepatobiliary–pancreatic unit, we evaluated the effect of a surgery-specific goal-directed therapy (GDT) physiologic algorithm on complications and length of hospital stay. We compared patients who underwent pancreaticoduodenectomy with either a standardised Enhanced Recovery After Surgery program (usual care group), or a standardised Enhanced Recovery After Surgery program in combination with a surgery-specific cardiac output–guided algorithm (GDT group). We included 145 consecutive patients: 47 in the GDT group and 98 in the usual care group. Multivariable associations between GDT and lengths of stay and complications were investigated using negative binomial regression. Postoperative complications were common and occurred at similar frequencies amongst the GDT and usual care groups: 64% versus 68% respectively, P=0.71; odds ratio 0.82; (95% confidence interval 0.39–1.70). There were fewer cardiorespiratory complications in the GDT group. Median (interquartile range) length of hospital stay was ten days (8.0–14.0) in the GDT group compared to 13 days (8.8–21.3) in the usual care group, P=0.01. Median (interquartile range) total intraoperative fluid was 3,000 ml (2,050–4,175) in the GDT group compared to 4,500 ml (3,275–5,325) in the usual care group, P <0.0001; but by day one, the median (interquartile range) fluid balance was similar (1,198 ml [700–1,729] in the GDT group versus 977 ml [419–2,044] in the usual care group, P=0.96). Use of vasoactive medications was higher in the GDT group. In our patients undergoing pancreaticoduodenectomy, GDT was associated with restrictive intraoperative fluid intervention, fewer cardiorespiratory complications and a shorter hospital length of stay compared to usual care. However, we could not exclude an influence of surgical caseload, which we have previously found to be an important variable. We also could not relate the increased hospital length of stay to cardiorespiratory complications in individual patients. Therefore, these observational retrospective findings would require confirmation in a prospective randomised study.

Steps on how a phantom can be 3D printed and embedded within a medium suitable for training of ultrasound-guided procedures

Practice is required for acquiring procedural proficiency and this can be obtained from clinical practice, or more sensibly, having novices first practice the skill on an inanimate phantom or trainer. Commercially produced phantoms are expensive and 3D printing is becoming more cost effective. In our example, we have used a 3D-printed thoracic spine. This allows practitioners to improve their ultrasound-guided regional anesthesia needle imaging skills through deliberate practice. In this report, we describe in detail the requirements for producing a 3D-printed phantom comprising a 3D segment of thoracic spine set within a semi-solid medium.

IV-VI semiconductor growth on silicon substrates and new mid-infrared laser fabrication methods

This paper reviews results from research conducted at the University of Oklahoma on the development of new IV-VI semiconductor (lead salt) epitaxial growth and laser fabrication procedures that can ultimately lead to dramatic increases in mid-IR laser operating temperatures. Work has focused on growth of IV-VI semiconductor laser structures on silicon substrates using buffer layers that contain BaF2. Recent experiments show that it is possible to obtain high crystalline quality IV-VI semiconductor layer structures on (111)-oriented silicon substrates using molecular beam epitaxy (MBE) or on (100)-oriented silicon using a combination of MBE and liquid phase epitaxy (LPE). Experimental data for IV-VI semiconductor layer structures grown on silicon substrates including crystalline quality information as determined by high resolution X-ray diffraction (HRXRD) measurements and absorption edge information as determined by Fourier transform infrared (FTIR) transmission measurements are presented. Results show that these materials can be used to fabricate lasers that cover the 3 microns (3333 cm-1) to 16 microns (625 cm-1) spectral range. Removal of IV-VI semiconductor laser structures from the silicon growth substrate by dissolving BaF2 buffer layers with water is also demonstrated. This allows epitaxially-grown laser structures to be sandwiched between two heat sinks with a minimum of thermally resistive IV-VI semiconductor material. Theoretical modeling predicts that IV-VI lasers fabricated this way will have maximum continuous wave (cw) operating temperatures at least 60 degrees higher than those of IV-VI lasers fabricated on PbSe or PbTe substrates.

Fullerene Isomerism: Isolation of C2v,-C78 and D3-C78

Early reports on the formation of the higher fullerenes C(76), C(78), C(84), C(90), and C(94) by resistive heating of graphite stimulated theoretical calculations of possible cage structures for these all-carbon molecules. Among the five fullerene structures with isolated pentagons found for C(78), a closed-shell D3h-isomer was predicted to form preferentially. Two distinct C(78)-isomers were formed in a ratio of approximately 5:1 and could be separated by high-performance liquid chromatography. The carbon-13 nuclear magnetic resonance (NMR) spectrum of the major isomer is uniquely consistent with a C2v-structure. The NMR data also support a chiral D(3)-structure for the minor isomer. The isolation of specifically these two isomers of C(78) provides insight into the stability of higher fullerene structures and into the mechanism for fullerene formation in general.

A statistical assessment of orthodontic practices, product usage, and the development of skin lesions

Recently there has been great interest in skin lesions on the hands of orthodontic personnel who are exposed to a wide variety of metals, bonding agents, and other materials. Thus this 1985 national survey of 448 Canadian orthodontists (response rate 49%) was undertaken to examine orthodontic practice activities, bonding agent and wire product use, and prevalence of skin lesions on the hands and their possible association with these products. About 13% of the 213 responding orthodontists and at least one other staff member in 18% of the orthodontic practices reported the occurrence of hand lesions (reactions) over the preceding 3 years typical of exposure to dental materials. In nearly one fourth of the offices, at least one person was affected. Regarding product use. Concise, Mono-Lok, and Endur bonding agents and stainless steel, Nitinol, and Elgiloy wires were used most often. The orthodontists reported frequent involvement in bonding activities and infrequent use of gloves. Of all the individual and combined materials and practice characteristics and activities tested singly and multivariately for statistical association with hand lesions, only the orthodontists' use of Mono-Lok, gloves, and the activity of frequently cleaning excess bonding agent were statistically related to the lesions. Multiple logistic regression suggested that the statistical effects of Mono-Lok use and removal of excess bonding agent were independent; thus removal of excess agent may have consequences for lesion development separate from Mono-Lok use.

Differences in oral health status between institutionalized and non-institutionalized older adults

Differences in oral health status between independent and institutionalized adults have been difficult to interpret because the latter population is typically older and has a higher proportion of women, confounding any association between institutionalization and disease levels. We undertook an analysis of oral disease amongst institutionalized (n = 149) and non-institutionalized (n = 246) samples of older adults randomly selected from the population in East York, Ontario. When the confounding effects of age and gender were controlled by constructing 67 matched pairs, institutionalized people were more than twice as likely to be edentulous (OR = 2.17, 95% CI = 1.09-4.29). This association was confirmed using data from all subjects in a logistic regression model. Analysis of covariance of data from dentate subjects revealed that the institutionalized seniors had fewer filled teeth (P less than 0.05, controlling for age and sex), but there were no statistically significant differences in the number of teeth which were missing, decayed, or requiring extraction. These findings suggest that antecedent, sociodemographic factors prior to institutionalization are responsible for the higher probability of oral disease in this group of older adults.

Results of the socio-dental survey of people aged 50 and older living in East York, Ontario

We determined the oral health status and treatment needs of the current and future elderly in East York and tested four enrollment strategies for community-based surveys. We selected our sample from the Municipal Composite Report and obtained the data using a multi-item questionnaire and a clinical examination. The examination protocol was based on World Health Organization (WHO) methodology but was expanded to provide tooth surface specific information. Of those contacted by telephone and repeated mailings, 35% participated. The sample appeared representative of the community as determined by a follow-up mail survey of non-respondents. 76% of those examined were dentate and 71% had visited the dentist within the last two years. Nonetheless, 27% had chewing impairment, 15% had discomfort with their teeth and 15% needed care urgently. Treatment needs were highest for the 187 dentate. They required 504 extractions or restorations and 113 denture services. Periodontal care for calculus and pockets was needed by 86% of the dentate. This report shows an apparent contradiction of high dental treatment needs remaining in the context of reported high care-seeking rates.