COVID-19 presenting with spontaneous massive pneumomediastinum in a three-month-old child.

A three-month-old child presented to our district general hospital with acute respiratory distress. He was found to have massive spontaneous pneumomediastinum and extensive surgical emphysema overlying the neck. Tracheal intubation using the GlideScope® was difficult, and the patient's trachea was ultimately intubated with a direct laryngoscope. Computed tomography revealed bilateral lung consolidation and reverse transcriptase-polymerase chain reaction swab was positive for SARS-CoV-2. There was no other precipitating factor to explain the presence of pneumomediastinum. The patient was treated with pleural and mediastinal drains, required five days of mechanical ventilation on a paediatric intensive care unit and subsequently made a full recovery. We outline our initial differential diagnosis, airway management plan, and propose a mechanism for the development of spontaneous pneumomediastinum in this case. We suggest that clinicians should consider pneumomediastinum as a potential cause of surgical emphysema, particularly in the context of COVID-19, even in infants. To our knowledge, this is the first reported case of COVID-19 in this age group with spontaneous pneumomediastinum as the presenting feature.

Extreme hyperthermia tolerance in the world's most abundant wild bird.

The thermal tolerances of vertebrates are generally restricted to body temperatures below 45-47 °C, and avian and mammalian critical thermal maxima seldom exceed 46 °C. We investigated thermoregulation at high air temperatures in the red-billed quelea (Quelea quelea), an African passerine bird that occurs in flocks sometimes numbering millions of individuals. Our data reveal this species can increase its body temperature to extremely high levels: queleas exposed to air temperature > 45 °C increased body temperature to 48.0 ± 0.7 °C without any apparent ill-effect, with individual values as high as 49.1 °C. These values exceed known avian lethal limits, with tolerance of body temperature > 48 °C unprecedented among birds and mammals.

Bat thermoregulation in the heat: Limits to evaporative cooling capacity in three southern African bats.

High environmental temperatures pose significant physiological challenges related to energy and water balance for small endotherms. Although there is a growing literature on the effect of high temperatures on birds, comparable data are scarcer for bats. Those data that do exist suggest that roost microsite may predict tolerance of high air temperatures. To examine this possibility further, we quantified the upper limits to heat tolerance and evaporative cooling capacity in three southern African bat species inhabiting the same hot environment but using different roost types (crevice, foliage or cave). We used flow-through respirometry and compared heat tolerance limits (highest air temperature (Ta) tolerated before the onset of severe hyperthermia), body temperature (Tb), evaporative water loss, metabolic rate, and maximum cooling capacity (i.e., evaporative heat loss/metabolic heat production). Heat tolerance limits for the two bats roosting in more exposed sites, Taphozous mauritianus (foliage-roosting) and Eptesicus hottentotus (crevice-roosting), were Ta = ~44 °C and those individuals defended maximum Tb between 41 °C and 43 °C. The heat tolerance limit for the bat roosting in a more buffered site, Rousettus aegyptiacus (cave-roosting), was Ta = ~38 °C with a corresponding Tb of ~38 °C. These interspecific differences, together with a similar trend for higher evaporative cooling efficiency in species occupying warmer roost microsites, add further support to the notion that ecological factors like roost choice may have profound influences on physiological traits related to thermoregulation.

High temperatures are associated with substantial reductions in breeding success and offspring quality in an arid-zone bird.

During hot weather, terrestrial animals often seek shaded thermal refugia. However, this can result in missed foraging opportunities, loss of body condition and impaired parental care. We investigated whether such costs could compromise breeding success in a widespread southern African bird: the Southern Yellow-Billed Hornbill Tockus leucomelas. We predicted that hornbills might be especially vulnerable to temperature-dependant reductions in parents' foraging capacity due to extreme asymmetry in sex-specific roles during breeding: females are confined within the nest cavity for most of the nesting period and the burden of provisioning falls solely on the male during this time. We followed 50 hornbill nesting attempts in the Kalahari Desert between 2012 and 2015, collecting data on provisioning rates, adult and nestling body mass, fledging success and size of fledglings. Mean daily maximum air temperatures (Tmax) during nesting attempts ranged from 33.2 to 39.1 °C. The likelihood of successful fledging fell below 50% at mean Tmax > 35.1 °C; a threshold now regularly exceeded at our study site due to recent climate warming. Additionally, offspring fledging following the hottest nesting attempts were > 50% lighter than those fledging following the coolest. Sublethal costs of keeping cool including loss of body condition, production of poor-quality offspring and breeding failure are likely to become issues of serious conservation concern as climate change progresses; even for currently widespread species. Missed-opportunity costs associated with behavioral thermoregulation and direct sublethal costs of temperature exposure should not be overlooked as a potential threat to populations, especially in environments that are already hot.

Temporal Trends and Future Predictions of Regional EMS System Utilization Using Statistical Modeling.

INTRODUCTION: Trends in utilization of Emergency Medical Services (EMS) systems can be used to extrapolate future use of an EMS system, which will be valuable for the budgeting and planning of finances and resources. The best model for incorporation of seasonal and regional fluctuations in utilization to predict future utilization is unknown. PROBLEM: Authors aimed to trend patterns of utilization in a regional EMS system to identify the needs of a growing population and to allow for a better understanding of how the EMS system is used on a basis of call volume and frequency of EMS transportation. The authors then used a best-fitting prediction model approach to show how the studied EMS system will be used in future years. METHODS: Systems data were retrospectively extracted by using the electronic medical records of the studied EMS system and its computer-assisted dispatch (CAD) database from 2010 through 2017. All EMS dispatches entering the system's 9-1-1 public service access point were captured. Annual utilization data were available from 2010 through 2017, while quarterly data were available only from 2013 through 2017. The 9-1-1 utilization per capita, Advanced Life Support (ALS) utilization per capita, and ALS cancel rates were calculated and trended over the study period. The methods of prediction were assessed through a best-fitting model approach, which statistically suggested that Additive Winter's approach (SAS) was the best fit to determine future utilization and ALS cancel rates. RESULTS: Total 9-1-1 call volume per capita increased by 32.46% between 2010 and 2017, with an average quarterly increase of 0.78% between 2013 and 2017. Total ALS call volume per capita increased by 1.93% between 2010 and 2017. Percent ALS cancellations (cancelled en route to scene) increased by eight percent between 2010 and 2017, with an average quarterly increase of 0.42% (2013-2017). Predictions to end of 2019 using Additive Winter's approach demonstrated increasing trends in 9-1-1 call volume per capita (R2 = 0.47), increasing trends of ALS utilization per capita (R2 = 0.71), and increasing percent ALS cancellation (R2 = 0.93). Each prediction showed increasing future trends with a 95% confidence interval. CONCLUSIONS: The authors demonstrate paramount per capita increases of 9-1-1 call volume in the studied ALS system. There are concomitant increases of ALS cancellations prior to arrival, which suggests a potential burden on this regional ALS response system.

Antiplatelet drugs: a review of pharmacology and the perioperative management of patients in oral and maxillofacial surgery.

INTRODUCTION: An increasing number of patients are taking oral antiplatelet agents. As a result, there is an important patient safety concern in relation to the potential risk of bleeding complications following major oral and maxillofacial surgery. Surgeons are increasingly likely to be faced with a dilemma of either continuing antiplatelet therapy and risking serious haemorrhage or withholding therapy and risking fatal thromboembolic complications. While there are national recommendations for patients taking oral antiplatelet drugs undergoing invasive minor oral surgery, there are still no evidence-based guidelines for the management of these patients undergoing major oral and maxillofacial surgery. METHODS: MEDLINE and EMBASE databases were searched to retrieve all relevant articles published to 31 December 2017. FINDINGS: A brief outline of the commonly used antiplatelet agents including their pharmacology and therapeutic indications is discussed, together with the haemorrhagic and thromboembolic risks of continuing or altering the antiplatelet regimen in the perioperative period. Finally, a protocol for the management of oral and maxillofacial patients on antiplatelet agents is presented. CONCLUSIONS: Most current evidence to guide decision making is based upon non-randomised observational studies, which attempts to provide the safest possible management of patients on antiplatelet therapy. Large randomised clinical trials are lacking.

The costs of keeping cool: behavioural trade-offs between foraging and thermoregulation are associated with significant mass losses in an arid-zone bird.

Avian responses to high environmental temperatures include retreating to cooler microsites and/or increasing rates of evaporative heat dissipation via panting, both of which may affect foraging success. We hypothesized that behavioural trade-offs constrain the maintenance of avian body condition in hot environments, and tested predictions arising from this hypothesis for male Southern Yellow-billed Hornbills (Tockus leucomelas) breeding in the Kalahari Desert. Operative temperatures experienced by the hornbills varied by up to 13 °C among four microsite categories used by foraging males. Lower prey capture rates while panting and reductions associated with the occupancy of off-ground microsites, resulted in sharp declines in foraging efficiency during hot weather. Consequently, male body mass (Mb) gain between sunrise and sunset decreased with increasing daily maximum air temperature (Tmax), from ~ 5% when Tmax < 25 °C to zero when Tmax = 38.4 °C. Overnight Mb loss averaged ~ 4.5% irrespective of Tmax, creating a situation where nett 24-h Mb loss approached 5% on extremely hot days. These findings support the notion that temperature is a major determinant of body condition for arid-zone birds. Moreover, the strong temperature dependence of foraging success and body condition among male hornbills provisioning nests raises the possibility that male behavioural trade-offs translate into equally strong effects of hot weather on female condition and nest success. Our results also reveal how rapid anthropogenic climate change is likely to substantially decrease the probability of arid-zone birds like hornbills being able to successfully provision nests while maintaining their own condition.

Ten thousand steps: a pedometer study of junior dentists in a major British teaching hospital and a district general hospital.

Sedentary behaviour is widely associated with deleterious health outcomes that in modern medicine have similar connotations to smoking tobacco and alcohol misuse. The integration of e-portfolio, e-logbook, British National Formulary (BNF) and encrypted emails has made smartphones a necessity for trainees. Smartphones also have the ability to record the amount of exercise taken, which allows activity at work to be monitored. The aim of this study to compare the activity of the same group of dental core trainees when they worked within a large multisite teaching hospital and a smaller district general hospital, to find out if supplementary activity was needed outside work. Data were collected from smartphones. To ensure continuity, data were collected only from those who had calibrated iPhones (n=10). At the teaching hospital six of the trainees walked over 10 000 steps a day while working (mean (SD) 10 004 (639)). At the district hospital none of the trainees walked 10 000 steps. The mean (SD) number of steps completed by all trainees was 6265 (119). Walking at work provides the full quota of recommended daily exercise most of the time for those working in the teaching hospital, but additional exercise is occasionally required. While working at the district hospital they walk less, meaning that they should try to increase their activity outside work. Trainees working in the teaching hospital walk significantly more steps than in the district hospital.

Scheduling terminology for oral and maxillofacial surgery. Are we speaking a universal language?

Use of a universal vocabulary to assist with the scheduling of operations has been shown to considerably reduce delays and improve the use of theatre resources. Within the UK the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) has established a classification to assist with the triage of both emergency and non-emergency operating lists. We completed a survey to assess the uptake and understanding of this classification when scheduling maxillofacial operations. From a list of eight scheduling terms, respondents had to choose one each for 20 different clinical situations (that represented equally) immediate, urgent, expedited, and elective operations as defined by them. A total of 50 surveys were collated. Only 65% of answers selected represented NCPOD terms. 25% of answers represented a term higher and 18% a term lower, on the scale of intervention for the same category of situation. Current NCEPOD terms do not seem to be used universally and are poorly understood. Considerable variation in terminology exists when scheduling maxillofacial operations.

Regulation of Heat Exchange across the Hornbill Beak: Functional Similarities with Toucans?

Beaks are increasingly recognised as important contributors to avian thermoregulation. Several studies supporting Allen's rule demonstrate how beak size is under strong selection related to latitude and/or air temperature (Ta). Moreover, active regulation of heat transfer from the beak has recently been demonstrated in a toucan (Ramphastos toco, Ramphastidae), with the large beak acting as an important contributor to heat dissipation. We hypothesised that hornbills (Bucerotidae) likewise use their large beaks for non-evaporative heat dissipation, and used thermal imaging to quantify heat exchange over a range of air temperatures in eighteen desert-living Southern Yellow-billed Hornbills (Tockus leucomelas). We found that hornbills dissipate heat via the beak at air temperatures between 30.7°C and 41.4°C. The difference between beak surface and environmental temperatures abruptly increased when air temperature was within ~10°C below body temperature, indicating active regulation of heat loss. Maximum observed heat loss via the beak was 19.9% of total non-evaporative heat loss across the body surface. Heat loss per unit surface area via the beak more than doubled at Ta > 30.7°C compared to Ta < 30.7°C and at its peak dissipated 25.1 W m(-2). Maximum heat flux rate across the beak of toucans under comparable convective conditions was calculated to be as high as 61.4 W m(-2). The threshold air temperature at which toucans vasodilated their beak was lower than that of the hornbills, and thus had a larger potential for heat loss at lower air temperatures. Respiratory cooling (panting) thresholds were also lower in toucans compared to hornbills. Both beak vasodilation and panting threshold temperatures are potentially explained by differences in acclimation to environmental conditions and in the efficiency of evaporative cooling under differing environmental conditions. We speculate that non-evaporative heat dissipation may be a particularly important mechanism for animals inhabiting humid regions, such as toucans, and less critical for animals residing in more arid conditions, such as Southern Yellow-billed Hornbills. Alternatively, differences in beak morphology and hardness enforced by different diets may affect the capacity of birds to use the beak for non-evaporative heat loss.

Adaptive thermoregulation during summer in two populations of an arid-zone passerine.

Heterothermy plays an important role in lowering the costs of thermoregulation in endotherms by reducing water and energy requirements. We tested predictions that birds in arid habitats should express fine-scale variation in their thermoregulatory patterns as a function of prevailing climatic conditions. We assessed effects of air temperature (Tair) and water vapor pressure deficit (D) on body temperature (Tb) in free-living White-browed Sparrow-Weavers (Plocepasser mahali) during summer in two arid habitats in the Kalahari Desert, South Africa, using data from a dry period at a hot, desert site (n=7 birds), and during a dry period (n=4 birds) and a wet period (n=5 birds) at a milder, semi-desert site. The desert birds maintained a significantly higher set-point Tb (41.5 degrees+/-0.2 degrees C, mean-SD) than semi-desert birds (40.2 degrees+/-0.2 degrees C). During the warmest part of day (12:00-18:00 hours), Tb increased significantly during periods of high Tair and/or high humidity, and mean and maximum Tb were up to 1.40 and 2.3 degrees C, respectively, above normal levels. However, as Tair increased, birds at the desert site maintained Tb at or below set-point levels for a greater proportion of the time than birds at the semi-desert site. Birds at the desert site also expressed a greater magnitude of daily heterothermy (heterothermy index, HI=2.4 degrees+/-0.3 degrees C, mean+/-SD) than birds at the semi-desert site: the latter population showed a greater magnitude of heterothermy during a dry period (HI=2.1 degrees+/-0.3 degrees C) than during a wet period (HI=1.6 degrees+/-0.2 degrees C). Birds continued foraging throughout the warmest part of the day, despite the fact that heat dissipation (percentage of time spent panting and wing-spreading) increased significantly with increasing Tair. Our findings reveal that populations can vary in their thermoregulatory responses in both space and time and suggest that small changes in Tair can have significant effects on thermoregulation in free-ranging desert birds, even when Tair

Vaccination and malignant disease: promising therapeutic approach.

Immunotherapy of cancer is now entering its second century. Much of our understanding of the complex interaction between tumours and the host immune system has come about because of technological and immunobiological advances in very recent years. For some malignancies, such as bladder cancer and malignant melanoma, immunotherapy is becoming an accepted form of adjuvant therapy. However, for most types of cancer, immunotherapy remains experimental and the majority of surgeons will have had little experience of immunotherapy in the clinical setting. This review provides a background to the scientific basis of immunotherapy, how different forms of immunotherapy are delivered and how their effects are monitored.

Immunological aspects of head and neck cancer: biology, pathophysiology and therapeutic mechanisms.

Advanced cancer and head and neck cancer, in particular, remains a major clinical challenge with its associated morbidity and inevitable mortality. Local control of early disease is achievable in many solid tumours with current surgical and radiotherapeutic techniques but metastatic disease is associated with poor outcome and prognosis. It is known that, by the time of presentation, many patients will already have occult microscopic metastatic disease, and surgery and radiotherapy will not result in long-term survival. What little effect modern chemotherapeutic agents have on microscopic disease is, however, limited by systemic toxicity and multi-drug resistance. Immune surveillance is postulated to be operative in man. There is evidence, however, that patients with progressive tumour growth have failure of host defences both locally and systemically. Various possible defects and tumour escape mechanisms are discussed in the review. Immunotherapy and, in particular adoptive T cell therapy and DC therapy, show promise as putative tumour-specific therapy with clinical benefits. These techniques are undergoing development and evaluation in phase 1 clinical trials. Preliminary data suggest that the treatments are well tolerated. Unfortunately, there is limited evidence of significant and prolonged improvements in clinical outcome. Further developments of beneficial protocols (adjuvants, mode and frequency of vaccination etc) and multicentre studies of the use of immunotherapy in cancer are now required.

Facultative hypothermic responses in an Afrotropical arid-zone passerine, the red-headed finch (Amadina erythrocephala).

We investigated thermoregulation and facultative hypothermic responses to food deprivation in the red-headed finch (Amadina erythrocephala), a 22-g passerine endemic to the arid regions of southern Africa. We predicted that, like most other passerines investigated, A. erythrocephala exhibits shallow rest-phase hypothermia, but not torpor. We observed significant reductions in rest-phase energy expenditure and body temperature (Tb) in response to restricted feeding. The maximum extent of Tb reduction (ca. 5 degrees C) and energy savings (ca. 10%) were consistent with those reported for a number of other passerine species. The lowest Tb we observed in a bird able to arouse spontaneously was 34.8 degrees C. The parameters of facultative hypothermic responses in A. erythrocephala were indicative of shallow rest-phase hypothermia, but not torpor. The limited available data on hypothermic responses in passerines suggest that many species do not possess the capacity for torpor. In passerines, torpor appears to be restricted to a few nectarivores and aerial insectarivores, and may have evolved independently of the torpor observed in non-passerine taxa such as the Trochiliformes and Caprimulgidae. The basal metabolic rate (BMR) of A. erythrocephala was 30-46% lower than predicted by various allometric equations, but was similar to the predicted BMR for a 22-g desert bird.