Peri-operative COVID-19 infection in urgent elective surgery during a pandemic surge period: a retrospective observational cohort study

Maintaining safe elective surgical activity during the global coronavirus disease 2019 (COVID-19) pandemic is challenging and it is not clear how COVID-19 may impact peri-operative morbidity and mortality in this population. Therefore, adaptations to normal care pathways are required. Here, we establish if implementation of a bespoke peri-operative care bundle for urgent elective surgery during a pandemic surge period can deliver a low COVID-19-associated complication profile. We present a single-centre retrospective cohort study from a tertiary care hospital of patients planned for urgent elective surgery during the initial COVID-19 surge in the UK between 29 March and 12 June 2020. Patients asymptomatic for COVID-19 were screened by oronasal swab and chest imaging (chest X-ray or computed tomography if aged ≥ 18 years), proceeding to surgery if negative. COVID-19 positive patients at screening were delayed. Postoperatively, patients transitioning to COVID-19 positive status by reverse transcriptase polymerase chain reaction testing were identified by an in-house tracking system and monitored for complications and death within 30 days of surgery. Out of 557 patients referred for surgery (230 (41.3%) women; median (IQR [range]) age 61 (48-72 [1-89])), 535 patients (96%) had COVID-19 screening, of which 13 were positive (2.4%, 95%CI 1.4-4.1%). Out of 512 patients subsequently undergoing surgery, 7 (1.4%) developed COVID-19 positive status (1.4%, 95%CI 0.7-2.8%) with one COVID-19-related death (0.2%, 95%CI 0.0-1.1%) within 30 days. Out of these seven patients, four developed pneumonia, of which two required invasive ventilation including one patient with acute respiratory distress syndrome. Low rates of COVID-19 infection and mortality in the elective surgical population can be achieved within a targeted care bundle. This should provide reassurance that elective surgery can continue, where possible, despite high community rates of COVID-19.

Logistic early warning scores to predict death, cardiac arrest or unplanned intensive care unit re-admission after cardiac surgery

NHS England recently mandated that the National Early Warning Score of vital signs be used in all acute hospital trusts in the UK despite limited validation in the postoperative setting. We undertook a multicentre UK study of 13,631 patients discharged from intensive care after risk‐stratified cardiac surgery in four centres, all of which used VitalPAC^TM to electronically collect postoperative National Early Warning Score vital signs. We analysed 540,127 sets of vital signs to generate a logistic score, the discrimination of which we compared with the national additive score for the composite outcome of: in‐hospital death; cardiac arrest; or unplanned intensive care admission. There were 578 patients (4.2%) with an outcome that followed 4300 sets of observations (0.8%) in the preceding 24 h: 499 out of 578 (86%) patients had unplanned re‐admissions to intensive care. Discrimination by the logistic score was significantly better than the additive score. Respective areas (95%CI) under the receiver‐operating characteristic curve with 24‐h and 6‐h vital signs were: 0.779 (0.771–0.786) vs. 0.754 (0.746–0.761), p < 0.001; and 0.841 (0.829–0.853) vs. 0.813 (0.800–0.825), p < 0.001, respectively. Our proposed logistic Early Warning Score was better than the current National Early Warning Score at discriminating patients who had an event after cardiac surgery from those who did not.

Sensitometric comparison of speed group E and F dental radiographic films

OBJECTIVE

To evaluate the sensitometric characteristics of Insight, (Eastman Kodak, Rochester, NY, USA) a new F-speed film, in fresh and depleted processing solutions and compare them with Ektaspeed Plus.

METHODS

Two sets each of Insight (IP) and Ektaspeed Plus (EP) films were exposed to radiation levels ranging from 10.7 to 685.2 microGy. One set of films was processed in fresh chemicals while the other set was processed in solutions that had been used for 5 days to process over 500 radiographs. Unexposed films of both types were processed in both solutions to determine base-plus-fog density. Speed and contrast were measured according to ISO definitions and at other levels of density.

RESULTS

IP was in speed group F as measured at optical density 1 above base-plus-fog when processed under both conditions. It was 25% faster than EP when both were processed in new solutions and 35% faster in the old solutions, permitting a 20-24% reduction in exposure time. The speeds of both film types decreased when processed in used solutions, but the decrease was smaller for IP than for EP. Speeds at other density levels were greater for IP than EP. Contrast as defined by ISO, and over other density ranges, was similar for both films.

CONCLUSIONS

Insight is an F-speed film with a speed at least 25% greater than Ektaspeed Plus. IP is more resistant than Ektaspeed Plus to decreases in speed when processed in used chemicals. Contrast of IP and EP is comparable over several density ranges.

Tissue radiation dosages using the RVG-S with and without niobium filtration

Tissue doses for a modified Rando head- and-neck phantom were measured for imaging with speed group E film with standardized aluminium filtration and the RVG-S both with and without added niobium filtration. Cylindrical holes drilled into the phantom's tissue-equivalent material permitted the placement of a small ionization chamber into anatomically correct sites representing the thyroid, parotid, submandibular and sublingual glands. To establish the necessary cone positions, angulations and time settings for each exposure, diagnostically acceptable images of six teeth, representative of different intraoral regions, were made for a DXXTR mannequin. Entrance and exit points were marked and transferred to the phantom to allow reproducible repeat exposures. The RVG-S provided reductions in average skin entrance dose of 31 per cent to 39 per cent with standard aluminium filtration and 51 per cent to 60 per cent with the addition of niobium filtration to attenuate the beam. While dose reductions relative to E-speed film usage were found for deep tissue sites, these were site and projection specific. The cumulative reduction from use of the RVG-S without niobium filtration was 32 per cent. It was 42 per cent with additional niobium filtration. It should be noted, however, that adding niobium filtration resulted in increased dosages to the deeper soft tissues such as the thyroid gland.

Imaging of the temporomandibular joint: a position paper of the American Academy of Oral and Maxillofacial Radiology

Various imaging techniques for the temporomandibular joint are discussed with respect to uses, strengths, and limitations. An imaging protocol is outlined for evaluating patients with a wide variety of temporomandibular joint related signs and symptoms.

Adaptation of the temporomandibular joint to altered mandibular function

This pilot study describes responses of Sprague Dawley rats to mandibular retrusion. Lingually overcontoured crowns were cemented onto maxillary incisors to produce 3.5 mm of autoretrusion. Monitoring data indicate that activity was suppressed and nutritional intake was reduced. Histological evaluation of the 2-, 4-, 7-, and 59-day test specimens detected only a monocytic infiltrate response in the 4-day group.

Evaluation of the potential of a polylactic acid barrier for correction of periodontal defects in baboons: a clinical and histologic study

Created periodontal defects in baboons were treated with one of four possible treatment modes: (1) root preparation and Epi-Guide biodegradable polylactic acid barrier, (2) root preparation and Gore-Tex e-PTFE membrane, (3) root preparation only (no barrier), and (4) no root preparation and no barrier (control). Root preparation consisted of hand instrumentation and use of finishing burs. Measurements of gingival recession were recorded from color photographic slides taken weekly for 6 weeks following barrier placement. Block sections were removed from one animal 6 weeks after barrier placement and prepared for histologic evaluation. Significantly more gingival recession was observed at the Gore-Tex sites than at the Epi-Guide sites. There were no significant differences in gingival recession between the Epi-Guide sites and root preparation-only sites or control sites. Both types of barriers were histologically acceptable. At 6 weeks, the Epi-Guide material was present histologically in a partially resorbed state. There was a mild inflammatory reaction in the surrounding connective tissues.

Lateral cephalometric analysis of skeletal patterns in patients with and without internal derangement of the temporomandibular joint

Twenty-three female volunteers with normal temporomandibular joints (TMJ) were compared with 24 female patients with documented TMJ internal derangements. Magnetic resonance imaging and lateral cephalometric radiographs were used to investigate the relationship between TMJ disk displacement and skeletal facial form. Results indicated that the patients with internal derangements have significantly smaller mandibles and maxillae. However, these sagittal measurements of jaw length were not associated with disproportionate changes in other cephalometric variables. In general, no district relationship was found between the morphologic features of the face and the internal derangements of the temporomandibular joint.

Combination treatment using decalcified freeze-dried bone allograft with guided tissue regeneration in human periodontal defects: two case reports

The ultimate goal of periodontal therapy should not be limited to the establishment and maintenance of periodontal health. The potential regeneration of the hard and soft periodontal tissues lost to disease also should be considered. Two case reports are presented to demonstrate the potential of guided tissue regeneration for this purpose.

Radiation doses of commonly used dental radiographic surveys

The purpose of this study was to evaluate and to compare the radiation dose associated with commonly used dental radiographic surveys including the following: (1) 20 film full-mouth survey, (2) bite-wing radiographs, (3) panoramic survey supplemented with bite-wing radiographs and (4) a common orthodontic radiographic survey (a lateral cephlometric radiograph supplemented with a panoramic radiograph). The effects of collimation and faster radiographic film speeds on dose were also investigated. The effective doses to selected anatomic sites were calculated from measured absorbed doses with the use of an improved, tissue-equivalent phantom fitted with lithium fluoride thermoluminescent dosimeters. It was demonstrated that converting from round to rectangular collimation reduced the radiation exposure by a factor of four. A panoramic survey supplemented with bite-wing radiographs uses approximately one third of the radiation exposure needed to expose a full-mouth survey made with E-speed film and rectangular collimation.

Condylar position as a predictor of temporomandibular joint internal derangement

Scout tomograms and arthrograms of 243 patients were separated and numbered. The location of the condyle within the fossa in the closed-mouth position was assessed by means of three evaluation techniques. Later, the arthrograms were interpreted and matched with the corresponding tomograms to evaluate the relationship between posterior displacement of the condyle and anterior displacement of the articular disk. The position of the disk within the fossa was found to be extremely variable whether disk position was normal or abnormal.

Radiation dosimetry in specific area radiography

An improved head-and-neck phantom was constructed from a human skull, cervical vertebrae, and Mix D, a mixture of wax, plastic, and metal oxides with x-ray absorbing and scattering properties similar to water and soft tissues. Lithium fluoride thermoluminescent dosimeters were calibrated and then exposed within the phantom. The doses at 17 anatomic sites were calculated for each of the 18 specific area radiographs in a complete intraoral radiographic survey.

An improved head-and-neck phantom for radiation dosimetry

To obtain accurate estimates of radiation doses within the head and neck, a phantom was constructed. The osseous structures were represented by a human skull and cervical vertebrae with Mix D simulating the soft tissues originally with the bone. The soft tissues of the head and neck were also represented by this mixture of wax, plastic, magnesium oxide, and titanium dioxide with the x-ray absorption and scattering properties nearly equal to water and soft tissue. Soft tissue thicknesses and facial contours were based on depths reported in the literature and supplemented by cadaver measurements. Air passages, air cells, sinuses, and the oral cavity were left open to accurately simulate the patient. The locations of 16 anatomic sites were based on cadaver dissection and measured relationships to osseous landmarks and the skin surface. To confirm the accuracy of the phantom, doses were measured with lithium fluoride thermoluminescent dosimeters and compared with the results of other investigations reported in the literature.

The effects of temporomandibular joint internal derangement and degenerative joint disease on tomographic and arthrotomographic images

In a blind study, 243 arthrograms were interpreted as showing normal disk position, anterior disk displacement with reduction, or anterior disk displacement without reduction. The presence or absence of a perforation of the posterior attachment or disk was recorded. Later, tomograms of the same patient were interpreted. The presence or absence of evidence of temporomandibular degenerative joint disease (TMDJD) was recorded. The condyle-to-fossa relationship was characterized as retropositioned or not retropositioned. O the 106 cases with tomographic evidence of TMDJD, 100 (94%) had arthrographic evidence of internal derangement (p less than 0.0001), whereas 47% of the cases with internal derangement (211) had evidence of TMDJD. Perforations were seen in 29 (27%) of the cases with degenerative joint disease and in none (0%) of the cases without TMDJD (p less than 0.001). In cases without TMDJD, 90% of the cases with internal derangement revealed condylar retropositioning (p less than 0.0001). With tomographic evidence of TMDJD present, the relationship between condylar position and disk position was not significant.

Interobserver reliability of methods for paleopathological diagnosis of dental caries

There is disagreement as to whether clinical methods of caries diagnosis will produce reliable results in skeletal material, and studies vary greatly in the extent to which such methods are employed. The purpose of this study is, therefore, to evaluate the interobserver reliability of visual, tactile, and radiographic methods of scoring dental caries in ancient populations. Thirty-three individuals from a Mogollon skeletal sample were scored on three occasions by pairs of examiners. The first exam employed visual criteria alone. In the second exam, visual methods were supplemented with the dental explorer. For the third exam, mesial and distal surfaces were scored from "intraoral" radiographs. Examiners worked independently, but did calibrate on material from clinical populations prior to the second and third exams. Exams were conducted on a "blind" basis, and analysis was delayed until all exams were completed. Caries scores were expressed as a percentage of total surfaces present per individual. Repeat-measures ANOVA and intraclass correlation coefficients (ICC) were used to estimate interobserver reliabilities. For visual scores, ICC = 0.97, and there is no significant difference between examiners (P = 0.897). For visual plus explorer scores, ICC drops to 0.90, and there is a significant difference between examiners (P = 0.003). For the radiographs, ICC = 0.86, and there is no significant difference between observers (P = 0.117). These results suggest that clinical methods are less reliable in skeletal populations.(ABSTRACT TRUNCATED AT 250 WORDS)