The Coronavirus Disease 2019 Pandemic's Effect on Critical Care Resources and Health-Care Providers: A Global Survey

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has severely affected ICUs and critical care health-care providers (HCPs) worldwide.

RESEARCH QUESTION

How do regional differences and perceived lack of ICU resources affect critical care resource use and the well-being of HCPs?

STUDY DESIGN AND METHODS

Between April 23 and May 7, 2020, we electronically administered a 41-question survey to interdisciplinary HCPs caring for patients critically ill with COVID-19. The survey was distributed via critical care societies, research networks, personal contacts, and social media portals. Responses were tabulated according to World Bank region. We performed multivariate log-binomial regression to assess factors associated with three main outcomes: limiting mechanical ventilation (MV), changes in CPR practices, and emotional distress and burnout.

RESULTS

We included 2,700 respondents from 77 countries, including physicians (41%), nurses (40%), respiratory therapists (11%), and advanced practice providers (8%). The reported lack of ICU nurses was higher than that of intensivists (32% vs 15%). Limiting MV for patients with COVID-19 was reported by 16% of respondents, was lowest in North America (10%), and was associated with reduced ventilator availability (absolute risk reduction [ARR], 2.10; 95% CI, 1.61-2.74). Overall, 66% of respondents reported changes in CPR practices. Emotional distress or burnout was high across regions (52%, highest in North America) and associated with being female (mechanical ventilation, 1.16; 95% CI, 1.01-1.33), being a nurse (ARR, 1.31; 95% CI, 1.13-1.53), reporting a shortage of ICU nurses (ARR, 1.18; 95% CI, 1.05-1.33), reporting a shortage of powered air-purifying respirators (ARR, 1.30; 95% CI, 1.09-1.55), and experiencing poor communication from supervisors (ARR, 1.30; 95% CI, 1.16-1.46).

INTERPRETATION

Our findings demonstrate variability in ICU resource availability and use worldwide. The high prevalence of provider burnout and its association with reported insufficient resources and poor communication from supervisors suggest a need for targeted interventions to support HCPs on the front lines.

Prognosticating Functional Outcome After Intracerebral Hemorrhage: The ICHOP Score

BACKGROUND

The morbidity, mortality, and monetary cost associated with intracerebral hemorrhage (ICH) is devastatingly high. Several scoring systems have been proposed to prognosticate outcomes after ICH, although the original ICH Score is still the most widely used. However, recent research suggests that systemic physiologic factors, such as those included in the Acute Physiology and Chronic Health Evaluation II score, may also influence outcome. In addition, no scoring systems to date have included premorbid functional status. Therefore, we propose a scoring system that incorporates these factors to prognosticate 3-month and 12-month functional outcomes.

METHODS

We used the Random Forest machine-learning technique to identify factors from a dataset of more than 200 data points per patient that were most strongly affiliated with functional outcome. We then used linear regression to create an initial model based on these factors and modified weightings to improve accuracy. Our scoring system was compared with the ICH Score for prognosticating functional outcomes.

RESULTS

Two separate scoring systems (Intracerebral Hemorrhage Outcomes Project 3 [ICHOP₃] and ICHOP₁₂) were developed for 3-month and 12-month functional outcomes using Glasgow Coma Scale, National Institutes of Health Stroke Scale, Acute Physiology and Chronic Health Evaluation II, premorbid modified Rankin Scale (mRS), and hematoma volume (3-month only). Patient outcomes were dichotomized into good (mRS score, 0-3) and poor (mRS score, 4-6) categories based on functional status. Areas under the curve in the derivation cohort for predicting mRS score were 0.89 (3-month) and 0.87 (12-month); both were significantly more discriminatory than the original ICH Score.

CONCLUSIONS

The ICHOP scores may provide more comprehensive evaluation of a patient's long-term functional prognosis by taking into account systemic physiologic factors as well as premorbid functional status.

An overview of burning mouth syndrome for the dermatologist

Burning mouth syndrome is characterized by an idiopathic burning pain affecting the oral mucosa, with no clinically apparent changes. It can present to a variety of health professionals including dermatologists. This article summarizes the important aspects of the condition, including theories of pathogenesis, diagnosis and management.

Retroperitoneal lymph node dissection for metastatic germ cell tumours

INTRODUCTION

In the North Trent Cancer network (NTCN) patients requiring retroperitoneal lymphadenectomy for metastatic testicular cancer have been treated by vascular service since 1990. This paper reviews our experience and considers the case for involvement of vascular surgeons in the management of these tumours.

PATIENTS AND METHODS

Patients referred by the NTCN to the vascular service for retroperitoneal lymphadenectomy between 1990 and 2009 were identified through a germ cell database. Data were supplemented by a review of case notes to record histology, intraoperative and postoperative details.

RESULTS

A total of 64 patients were referred to the vascular service for retroperitoneal lymph node dissection, with a median age of 29 years (16-63 years) and a median follow-up of 4.9 years. Ten patients died: eight from tumour recurrence, one from septicaemia during chemotherapy and one by suicide. Of the 54 who survived, 7 were alive with residual masses and 47 patients were disease-free at the last follow-up. Sixteen patients required vascular procedures: four had aortic repair (fascia), three had aortic replacement (spiral graft), four had inferior vena cava resection, two had iliac artery replacement and two had iliac vein resection.

CONCLUSIONS

Retroperitoneal lymph node dissection often involves mobilisation and/or the resection/replacement of major vessels. We recommend that a vascular surgeon should be a part of testicular germ cell multidisciplinary team.

The Effect of Hemispheric Synchronization on Intraoperative Analgesia

In this double-blinded randomized study, we sought to confirm that patients undergoing general anesthesia who were exposed to a hemispheric synchronization (Hemi-Sync) musical recording during surgery had a smaller analgesia requirement, as was suggested in a previous study. Bispectral index monitoring was used to adjust depth of hypnosis, and hemodynamic variables were used to determine analgesia administration. Consented patients underwent either laparoscopic bariatric or one-level lumbar disk surgery. After endotracheal intubation and application of headphones, baseline heart rate and arterial blood pressure were established. Isoflurane was titrated to maintain sedation on the basis of a target bispectral index range of 40-60, and 25-microg increments of fentanyl were administered in response to increases in heart rate and systolic arterial blood pressure. Bariatric patients who listened to Hemi-Sync required one-third less fentanyl than the control group (mean [SD]: 0.015 [0.01] vs 0.024 microg.kg(-1).min(-1) [0.01]) (P = 0.009). It is interesting to note that lumbar patients in the experimental and control groups required similar amounts of fentanyl (0.012 [0.01] vs 0.015 microg.kg(-1).min(-1) [0.01]). End-tidal isoflurane concentration was similar for Hemi-Sync and blank-tape patients (bariatric, 0.74% (0.14) vs 0.77% (0.21); lumbar, 0.36% [0.16] vs 0.39% [0.12]). The bariatric patients in this study demonstrated that Hemi-Sync may be an innovative intraoperative supplement to analgesia.

IMPLICATIONS

The purpose of this study was to determine the decrease in analgesia requirement for patients listening to hemispheric synchronization (musical tones) while under general anesthesia. We demonstrated that bariatric patients who listened to hemispheric synchronization had a smaller analgesia requirement than those who listened to a blank tape.

Heregulin enhances regenerative proliferation in postnatal rat utricular sensory epithelium after ototoxic damage

Hair cell loss due to acoustic and ototoxic damage often leads to hearing and balance impairments. Although a spontaneous event in chicks and lower vertebrates, hair cell replacement occurs at a much lower frequency in mammals presumably due to a very low rate of supporting cell proliferation following injury. We report here that heregulin, a member of the neuregulin family, dramatically enhances proliferation of supporting cells in postnatal rat utricular epithelial sheet cultures after gentamicin treatment, as revealed by bromo-deoxyuridine (BrdU) immunocytochemistry. A dose-dependent study shows that the maximal effects of heregulin are achieved at 3 nM. The mitogenic effects of heregulin are confirmed in utricular whole mount cultures. Autoradiography of the utricular whole mount cultures shows that heregulin also enhances the number of tritiated thymidine-labeled cells within the hair cell layer. TaqMan quantitative RT-PCR analysis and immunocytochemistry reveal that heregulin and its binding receptors (ErbB-2, ErbB-3 and ErbB-4) are expressed in the inner ear sensory epithelium. Of several ligands activating various ErbB receptors, including heregulin, neuregulin-3, beta-cellulin, heparin binding-epidermal growth factor (HB-EGF), transforming growth factor-alpha (TGF-alpha) and EGF, heregulin shows the most potent mitogenic effects on supporting cells. Because neuregulin-3 that signals only through ErbB-4 does not show an effect, these data suggest that activation of the ErbB-2-ErbB-3 heterodimeric complexes, rather than ErbB-4, is critical for the proliferative response in the utricular sensory epithelium. In addition, gentamicin treatment induces an upregulation of heregulin mRNA. Considered together, heregulin may play an important role in hair cell regeneration following ototoxic damage.

Distinct expression patterns of notch family receptors and ligands during development of the mammalian inner ear

The cochlea and vestibular structures of the inner ear labyrinth develop from the otic capsule via step-wise regional and cell fate specification. Each inner ear structure contains a sensory epithelium, composed of hair cells, the mechanosensory transducers, and supporting cells. We examined the spatio-temporal expression of genes in the Notch signaling pathway, Notch receptors (Notch1-4) and two ligands, Jagged1 and Delta1, in the developing mammalian inner ear. Our results show that Notch1 and Jagged1 are first expressed in the otic vesicle, likely involved in differentiation of the VIIIth nerve ganglion neurons, and subsequently within the inner ear sensory epithelia, temporally coincident with initial hair cell differentiation. Notch1 expression is specific to hair cells and Jagged1 to supporting cells. Their expression persists into adult. Notch2, Notch3, Notch4, and Delta1 are excluded from the inner ear epithelia. These data support the hypothesis that Notch signaling is involved in hair cell differentiation during inner ear morphogenesis.

Establishment of conditionally immortalized rat utricular epithelial cell lines using a retrovirus-mediated gene transfer technique

Supporting cells in the inner ear sensory epithelium are most likely hair cell progenitors. In an effort to establish an in vitro model system of hair cell differentiation, we developed immortalized epithelial cell lines by transferring the tsA58 allele of the SV40 large T antigen oncogene into neonatal rat utricular supporting cells using a retrovirus. The established cell lines have been stably maintained continuously for more than 25 passages and display many features similar to primary supporting cells. They grow in patches and assume a polygonal morphology. Immunocytochemical characterization of the established cell lines reveals that these cells can be labeled by epithelial cell markers, but not by fibroblast, glial or neuronal markers. The immortalized cells grow rapidly in serum medium at permissive temperature, but the majority cease proliferation when cultured in serum free medium at non-permissive temperature. These cells respond to mitogenic growth factors including bFGF, EGF and TGF-alpha and express growth factor receptors in a manner similar to the primary supporting cells. Furthermore, we find that the cells undergo a morphological differentiation when cultured in serum free medium at non-permissive temperature in the presence of bFGF. Under these conditions, the cells shrink in size, become elongated, and express early hair cell markers such as calretinin and calmodulin. The utricular epithelial cell line we have established may potentially provide an invaluable system for studying hair cell differentiation and regeneration.

Mammalian myosin I alpha is concentrated near the plasma membrane in nerve growth cones

To determine if unconventional myosins play a role in nerve outgrowth, antibodies specific for rat brain derived mammalian myosin I alpha (MMI alpha) were used to label cultured rat superior cervical ganglion nerve cells. Observations were made at both the light and electron microscopic level of resolution using preparative procedures designed to enhance the ability to precisely determine the relationship between antibody label and cellular structures in order to map the distribution and structural association of this myosin. Immunofluorescence showed that MMI alpha has a punctate distribution throughout the nerve cell body, neurites, and growth cones. In growth cones, MMI alpha staining is sometimes elevated in thin peripheral regions of high actin content at the leading edge. Immunoelectron microscopy using colloidal gold conjugated antibodies showed that in growth cones MMI alpha is absent from membranous organelles and is concentrated primarily in the cell cortex adjacent to the cell membrane. The cortical label is equally distributed between upper and lower membranes. The plasma membrane association of the MMI alpha label persists under conditions in which the actin cytoskeleton is perturbed or removed, suggesting a direct association between a fraction of MMI alpha and the plasma membrane. MMI alpha label is also associated with the non-cortical actin cytoskeleton. Partial disruption of the actin cytoskeleton using cytochalasin B causes redistribution of only a subset of MMI alpha label. These data suggest a complex relationship between MMI alpha, the actin cytoskeleton, and the plasma membrane in the growth cone. In contrast to its localization in the growth cone, in neuronal cell bodies MMI alpha is also associated with tubulovesicular structures. This suggests that at this location MMI alpha may either act as an organelle motor or is passively transported to the plasma membrane on vesicles.

Comparison of the ability of freeze etch and freeze substitution to preserve actin filament structure

In order to test the ability of freeze substitution to accurately preserve the ultrastructure of the actin component of the cytoskeleton, the structure of rotary shadowed actin filaments was compared following preparation by glutaraldehyde fixation and freeze etch or freeze substitution. Freeze substituted actin filaments were further processed by either etching away frozen organic solvent or critical-point-drying before rotary shadowing. Comparison of filament diameters showed no significant difference between actin filaments that were directly etched and those that were freeze substituted and then etched. However, freeze substituted and then critical-point-dried filaments were significantly larger in diameter than filaments that were directly etched in water. The long pitch (right-handed) two start helix was not affected by the different methods of preparation. However, the left-handed "genetic" helical repeat that was prominent in actin filaments prepared by freeze etch was more difficult to detect in freeze substituted specimen, especially following critical-point-drying. Although the organization and distribution of actin filaments in extracted cells was similar in both freeze substituted and freeze etched specimens, there were some detectable differences. In cells that were freeze substituted and then critical-point-dried, filaments appeared to intersect at greater angles and seemed more "taut." These results suggest that freeze substitution can preserve the overall morphology of actin filaments, but some chemical or physical modification of macromolecular surface structure may occur during the substitution process and these changes may be further exaggerated by subsequent processing steps.

Nerve growth cone lamellipodia contain two populations of actin filaments that differ in organization and polarity

The organization and polarity of actin filaments in neuronal growth cones was studied with negative stain and freeze-etch EM using a permeabilization protocol that caused little detectable change in morphology when cultured nerve growth cones were observed by video-enhanced differential interference contrast microscopy. The lamellipodial actin cytoskeleton was composed of two distinct subpopulations: a population of 40-100-nm-wide filament bundles radiated from the leading edge, and a second population of branching short filaments filled the volume between the dorsal and ventral membrane surfaces. Together, the two populations formed the three-dimensional structural network seen within expanding lamellipodia. Interaction of the actin filaments with the ventral membrane surface occurred along the length of the filaments via membrane associated proteins. The long bundled filament population was primarily involved in these interactions. The filament tips of either population appeared to interact with the membrane only at the leading edge; this interaction was mediated by a globular Triton-insoluble material. Actin filament polarity was determined by decoration with myosin S1 or heavy meromyosin. Previous reports have suggested that the polarity of the actin filaments in motile cells is uniform, with the barbed ends toward the leading edge. We observed that the actin filament polarity within growth cone lamellipodia is not uniform; although the predominant orientation was with the barbed end toward the leading edge (47-56%), 22-25% of the filaments had the opposite orientation with their pointed ends toward the leading edge, and 19-31% ran parallel to the leading edge. The two actin filament populations display distinct polarity profiles: the longer filaments appear to be oriented predominantly with their barbed ends toward the leading edge, whereas the short filaments appear to be randomly oriented. The different length, organization and polarity of the two filament populations suggest that they differ in stability and function. The population of bundled long filaments, which appeared to be more ventrally located and in contact with membrane proteins, may be more stable than the population of short branched filaments. The location, organization, and polarity of the long bundled filaments suggest that they may be necessary for the expansion of lamellipodia and for the production of tension mediated by receptors to substrate adhesion molecules.

Isolation and molecular characterization of a highly polymorphic centromeric tandem repeat in the family Falconidae

An abundant tandem repeat has been cloned from genomic DNA of the merlin (Falco columbarius). The cloned sequence is 174 bp in length, and maps by in situ hybridization to the centromeric regions of several of the large chromosomes within the merlin karyotype. Complementary sequences have been identified within a variety of falcon species; these sequences are either absent or in very low copy number in the family Accipitridae. The cloned merlin repeat reveals highly polymorphic restriction patterns in the peregrine falcon (Falco peregrinus). These polymorphisms, which have been shown to be stably inherited within a family of captive peregrines, can be used to differentiate the Greenland and Argentina populations of this endangered raptor species.