Seven-day services in surgery and the "weekend effect" at a Japanese teaching hospital: a retrospective cohort study.

BACKGROUND: Hospitals deliver 24-h, 7-day care on a 5-day workweek model, as fewer resources are available on weekends. In prior studies, poorer outcomes have been observed with weekend admission or surgery. The purpose of this study was to investigate the effect of 7-day service at a hospital, including outpatient consultations, diagnostic examinations and elective surgeries, on the likelihood of the "weekend effect" in surgery. METHODS: This was a retrospective cohort study of patients who underwent surgery between April 2014 and October 2016 at an academic medical centre in Tokyo, Japan. The main outcome measure was 30-day in-hospital mortality from the index surgery. The characteristics of the participants were compared using the Mann-Whitney U test or the chi-squared test as appropriate. Logistic regression was used to test for differences in the mortality rate between the two groups, and propensity score adjustments were made. RESULTS: A total of 7442 surgeries were identified, of which, 1386 (19%) took place on the weekend. Of the 947 emergency surgeries, 25% (235) were performed on the weekend. The mortality following emergency weekday surgery was 21‰ (15/712), compared with 55‰ (13/235) following weekend surgery. Of the 6495 elective surgeries, 18% (1151) were performed on the weekend. The mortality following elective weekday surgery was 2.3‰ (12/5344), compared with 0.87‰ (1/1151) following weekend surgery. After adjustment, weekend surgeries were associated with an increased risk of death, especially in the emergency setting (emergency odds ratio: 2.7, 95% confidence interval: 1.2-6.5 vs. elective odds ratio: 0.4, 95% confidence interval: 0.05-3.2). CONCLUSIONS: Patients undergoing emergency surgery on the weekend had higher 30-day mortality, but showed no difference in elective surgery mortality. These findings have potential implications for health administrators and policy makers who may try to restructure the hospital workweek or consider weekend elective surgery.

Noncontact Phased-Array Ultrasound Facilitates Acute Wound Healing in Mice.

BACKGROUND: The authors developed a noncontact low-frequency ultrasound device that delivers high-intensity mechanical force based on phased-array technology. It may aid wound healing because it is likely to be associated with lower risks of infection and heat-induced pain compared with conventional ultrasound methods. The authors hypothesized that the microdeformation it induces accelerates wound epithelialization. Its effects on key wound-healing processes (angiogenesis, collagen accumulation, and angiogenesis-related gene transcription) were also examined. METHODS: Immediately after wounding, bilateral acute wounds in C57BL/6J mice were noncontact low-frequency ultrasound- and sham-stimulated for 1 hour/day for 3 consecutive days (10 Hz/90.6 Pa). Wound closure (epithelialization) was recorded every 2 days as the percentage change in wound area relative to baseline. Wound tissue was procured on days 2, 5, 7, and 14 (five to six per time point) and subjected to histopathology with hematoxylin and eosin and Masson trichrome staining, CD31 immunohistochemistry, and quantitative polymerase-chain reaction analysis. RESULTS: Compared to sham-treated wounds, ultrasound/phased-array-treated wounds exhibited significantly accelerated epithelialization (65 ± 27 percent versus 30 ± 33 percent closure), angiogenesis (4.6 ± 1.7 percent versus 2.2 ± 1.0 percent CD31 area), and collagen deposition (44 ± 14 percent versus 28 ± 13 percent collagen density) on days 5, 2, and 5, respectively (all p < 0.05). The expression of Notch ligand delta-like 1 protein (Dll1) and Notch1, which participate in angiogenesis, was transiently enhanced by treatment on days 2 and 5, respectively. CONCLUSIONS: The authors' noncontact low-frequency ultrasound phased-array device improved the wound-healing rate. It was associated with increased early neovascularization that was followed by high levels of collagen-matrix production and epithelialization. The device may expand the mechanotherapeutic proangiogenesis field, thereby helping stimulate a revolution in infected wound care.

Developmental changes in the balance of glycolytic ATP production and oxidative phosphorylation in ventricular cells: A simulation study.

The developmental program of the heart requires accurate regulation to ensure continuous circulation and simultaneous cardiac morphogenesis, because any functional abnormalities may progress to congenital heart malformation. Notably, energy metabolism in fetal ventricular cells is regulated in a manner that differs from adult ventricular cells: fetal cardiomyocytes generally have immature mitochondria and fetal ventricular cells show greater dependence on glycolytic ATP production. However, although various characteristics of energy metabolism in fetal ventricular cells have been reported, to our knowledge, a quantitative description of the contributions of these factors to fetal ventricular cell functions has not yet been established. Here, we constructed a mathematical model to integrate various characteristics of fetal ventricular cells and predicted the contribution of each characteristic to the maintenance of intracellular ATP concentration and sarcomere contraction under anoxic conditions. Our simulation results demonstrated that higher glycogen content, higher hexokinase activity, and lower creatine concentration helped prolong the time for which ventricular cell contraction was maintained under anoxic conditions. The integrated model also enabled us to quantitatively assess the contributions of factors related to energy metabolism in ventricular cells. Because fetal cardiomyocytes exhibit similar energy metabolic profiles to stem cell-derived cardiomyocytes and those in the failing heart, an improved understanding of these fetal ventricular cells will contribute to a better comprehension of the processes in stem cell-derived cardiomyocytes or under pathological conditions.

Platelet-derived Factor Concentrates with Hyaluronic Acid Scaffolds for Treatment of Deep Burn Wounds.

A deep burn wound is a critical condition that generally necessitates vascularized tissue coverage. We performed the injection of platelet-derived factor concentrates combined with non-cross-linked hyaluronic acid scaffolds for 2 patients with critical burn wounds with bone and tendon exposure and achieved successful healing. Hyaluronic acid was considered to have served as a controlled-release carrier of platelet-derived factors, being clinically effective for the treatment of deep burn wounds.

The Stainless Steel Wire-based Method of Sogawa Effectively Corrects Severe Ingrown Nails.

Ingrown nails are defined as inflammation of the lateral nail fold that is caused by penetration by the nail plate and associates with pain and/or infection. The pain associated with ingrown nail hampers walking, raises the risk of falls, and decreases the quality of life. The Sogawa method is a novel conservative medical treatment for ingrown nails that is based on stainless steel wire. It was first reported in 2012 by Sogawa, and we have found that it is very effective for ingrown nails, especially in difficult cases. Here, we show the beneficial effects of the Sogawa method in 2 extremely difficult cases where ingrown nails had recurred after partial nail ablation. We found the Sogawa method to be a quick and easy technique that rapidly improves the pain associated with ingrown nails and later produces properly configured nails. Our experience suggests that it is suitable for severe ingrown nails, such as too short ingrown nails and ingrown nails that have strong inflammation and granulation tissue formation. This is significant because it is difficult to treat such cases with conventional conservative methods, which means that the only remaining therapeutic option is surgery. Thus, the Sogawa method is a novel and highly effective ingrown nail treatment that obviates the need for invasive surgical treatment.

A novel nonsurgical treatment for pincer nail that involves mechanical force control.

We hypothesize that nails have an automatic curvature feature and that their flat shape is maintained by the daily upward mechanical forces from the finger/toe pad. Thus, nail deformities, such as pincer nail, spoon nail, and koilonychias, may be caused by an imbalance between these forces and can be treated by controlling these forces. Here, we report the case of a 55-year-old man whose severe pincer nail was effectively treated by thinning the nail, which reduced the automatic curvature force. This is the first report to show that pincer nail can be treated by a nonsurgical method that reduces the automatic curvature force, thus obviating the need for surgery. This supports the notion that mechanical stimulus-based treatments have high therapeutic potential for nail deformities.

Influence of oxygen on wound healing dynamics in healing-impaired diabetic mice.

A previous experiment using an in vivo mouse model has proved that hypoxia increased angiogenesis during wound healing. It was hypothesised that one of the mechanisms for wound healing impairment in diabetes includes insufficient angiogenic ability in response to hypoxia. The current study aims to investigate the influence of hypoxia on wound healing in diabetic mice. Oxygen-impermeable (hypoxic group) and -permeable membranes (normoxic group) were used to control topical oxygen tension. Membranes were applied to symmetrical excisional wounds on diabetic mice. Wound area, granulated tissue thickness, and vascular density were analyzed. As results, a decrease in wound size on day 7 was observed in the normoxic group (20.7 ± 3.64%) compared with the hypoxic group (34.1 ± 4.98%). The normoxic group also showed significantly thicker granulated tissue than the hypoxic group (225.7 ± 54.7 vs 128.7 ± 42.4 µm). There was no significant difference in mean vascular density between normoxic and hypoxic groups (0.046 ± 0.022 vs 0.038 ± 0.017 mm(2)/mm(2), p = 0.80). Contrary to healthy mice, diabetic mice have shown no enhancement of angiogenesis in hypoxic condition. The findings illustrate that neovascularisation in response to hypoxia is diminished in diabetic wounds.

Great toe necrosis predicts an unfavorable limb salvage prognosis.

SUMMARY: The initial location of necrosis may affect the limb salvage rate. This study of 130 patients with chronic toe ulcers or gangrene was performed to assess whether the location of initial necrosis in the toes affected limb salvage prognosis. The patients were divided into 2 groups according to whether the initial necrosis was in the great toe or in other toes. Limb salvage prognosis was determined retrospectively. In the great toe group, the rates of total toe loss and major amputation were 50.0% and 24.4%, respectively. When the initial necrosis was in other toes, these rates were 27.3% and 9.3%, respectively. Great toe necrosis is associated with significantly higher rates of total toe loss (odds ratio = 3.10; P = 0.003; 95% confidence interval, 1.43-6.68) and major amputation (odds ratio = 3.66; P = 0.007; 95% confidence interval, 1.37-9.79). The great toe is supplied by 3 source arteries, whereas the lesser toes are fed by 1 or 2 arteries. Therefore, necrosis initiating from the great toe may reflect the presence of severe vascular disorders. The great toe is also anatomically connected to much of the foot via the tendons. Infection is more likely to spread along these tendons, which may reduce limb prognosis. Thus, the initial location of necrosis may be predictive of limb prognosis.

Clinical Evidence for the Relationship between Nail Configuration and Mechanical Forces.

SUMMARY: Mechanobiology is an emerging field of science that focuses on the way physical forces and changes in cell or tissue mechanics contribute to development, physiology, and disease. As nails are always exposed to physical stimulation, mechanical forces may have a particularly pronounced effect on nail configuration and could be involved in the development of nail deformities. However, the role of mechanobiology in nail configuration and deformities has rarely been assessed. This review describes what is currently understood regarding the effect of mechanical force on nail configuration and deformities. On the basis of these observations, we hypothesize that nails have an automatic curvature function that allows them to adapt to the daily upward mechanical forces. Under normal conditions, the upward daily mechanical force and the automatic curvature force are well balanced. However, an imbalance between these 2 forces may cause nail deformation. For example, pincer nails may be caused by the absence of upward mechanical forces or a genetic propensity increase in the automatic curvature force, whereas koilonychias may occur when the upward mechanical force exceeds the automatic curvature force, thereby causing the nail to curve outward. This hypothesis is a new concept that could aid the development of innovative methods to prevent and treat nail deformities.

Effect of mechanical forces on finger nail curvature: an analysis of the effect of occupation on finger nails.

BACKGROUND: We studied the relationship between mechanical force and nail curvature. METHODS: The effect of different frequencies and strengths of mechanical force on nail curvature was assessed. In Study 1, 63 carpenters and 63 office workers were enrolled, and the configurations of their thumb nails were assessed by measuring the curve index (defined as nail height/width) and pinch strength. In Study 2, nail curvature and pinch strength of jazz bassists, who characteristically do not use the right fourth and fifth fingers but use the left fifth finger a lot, were compared. In Study 3, the thumb nail curvature and pinch strength of the dominant and nondominant sides of the 126 participants from Study 1 were compared. RESULTS: Study 1: Carpenters had a significantly lower mean thumb nail curve index and higher mean pinch strength. Study 2: The nails of the unused right fourth and fifth fingers were much more curved than the nails of the frequently used left fourth and fifth fingers. The pinch strength of the right fifth finger was much weaker than the pinch strength of the left fifth finger. Study 3: The dominant side had a significantly lower nail curve index and higher pinch strength. CONCLUSION: The frequency and strength of mechanical forces on finger nails significantly affect nail appearance.

Elective use of an uncuffed small-bore cricothyrotomy tube with balloon occlusion of the subglottic airway.

PURPOSE: To conduct a qualitative observational study on positive pressure ventilation through a percutaneous uncuffed small-bore cricothyrotomy tube with balloon occlusion of the subglottic airway to minimize supraglottic leak. CLINICAL FEATURES: Ten consecutive procedures were performed in the nine men enrolled in this study. The demographics of the participants were: aged 50-73 yr, weight 48-87 kg, American Society of Anesthesiologists class I-II, and scheduled for endoscopic submucosal dissection via flexible endoscopy for en bloc resection of superficial meso- and hypopharyngeal cancer. The airway was initially secured with a supraglottic airway (SGA) under sevoflurane-based anesthesia, and a cricothyrotomy was then performed using a Portex(®) Minitrach II uncuffed cricothyrotomy tube (4-mm internal diameter). Following SGA removal, a Coopdech(®) bronchial blocker was orally or nasally inserted, and the balloon was inflated to occlude the trachea immediately beneath the glottis. The ventilator setting was initially based on observation of chest motion and end-tidal carbon dioxide tension and then readjusted according to arterial blood gas levels. All procedures were completed within a median time of 149 min. Effective ventilation was achieved in all patients despite mild hypercapnia (PaCO2 of 58 mmHg at maximum) in some patients. SpO2 levels were maintained at ≥ 98%. CONCLUSION: This technique provides effective intraoperative ventilation and easy endoscopic access, and it countermeasures against the likely complication of postoperative laryngeal edema. Moreover, there is no need for conventional tracheostomy or prolonged intubation. This approach establishes a curative and less invasive pharyngeal cancer therapy. Certain adverse outcomes can be avoided, including impaired speech and swallowing, possible delayed closure of the stoma, or a compromised cosmetic outcome.

Acellular adipose matrix as a natural scaffold for tissue engineering.

BACKGROUND: In conventional tissue-regeneration technologies, stem cells and/or other cells are injected into or incubated on scaffolds. In general, scaffolds can be classified into synthetic and natural polymers and natural matrices. Polymers are generally less suitable than natural matrices in terms of biocompatibility and biodegradability. A highly promising alternative may be the acellular adipose matrix (AAM), which is a natural scaffold that could mediate tissue regeneration without any artefacts. The optimal method for adipose-tissue decellularisation is described in this article. METHODS: Discarded human adipose tissues harvested from routine operations were used. In experiment 1, four different adipose-tissue-decellularisation methods were compared and modified. In experiment 2, the most effective method was tested by using adipose-tissue blocks from various donor sites (the abdomen, chest and forearm) and of different weights (0.8, 25 and 80 g). Haematoxylin and eosin (H &E) staining, immunohistochemistry (IHC) and scanning electron microscopy were used to determine the efficacy of decellularisation. RESULTS: In experiment 1, a method using an enzymatic digestion solution yielded complete decellularisation after some modifications. In experiment 2, the 0.8-g specimens were completely decellularised by the modified method. However, cell components remained in the 25- and 80-g specimens. The donor site had no effect on the degree of decellularisation. CONCLUSIONS: An optimal method for adipose-tissue decellularisation is reported. Because AAM is a natural collagen scaffold that is of human origin, this report describes an important first step in a tissue-engineering innovation that may be suitable for the regeneration of various tissues.

Comparison of collagen matrix treatment impregnated with platelet rich plasma vs bone marrow.

This study has reported the efficacy of an autologous bone marrow-impregnated collagen matrix experimentally and clinically. Then, it reflected that platelet rich plasma (PRP) was as good a source of growth factors as bone marrow and available in a less invasive procedure. This study aimed to compare the efficacy of a PRP-impregnated collagen matrix with that of a bone marrow-impregnated collagen matrix by quantifying wound size and capillary density using genetically diabetic db/db mice. Bone marrow cells were obtained from femurs of ddy mice. Then, a small amount of collagen matrix was immersed in bone marrow suspension. This is called a bone marrow-impregnated collagen matrix. PRP was obtained from healthy human blood and a small amount of collagen matrix was immersed in PRP. This is called a PRP-impregnated collagen matrix. A bone marrow-impregnated collagen matrix and PRP-impregnated collagen matrix were applied to excisional skin wounds on a genetically healing-impaired mouse (n = 6) and wounds were evaluated 6 days after the procedure. Wounds were divided into two groups: PRP (n = 6), in which a PRP-impregnated collagen matrix was applied; and bone marrow (n = 6), in which collagen immersed in a bone marrow suspension was applied. There was no significant difference between the PRP and bone-marrow groups in the rate of vascular density increase or wound size decrease. The present study suggested that the PRP-impregnated collagen matrix promotes repair processes at least as strongly as the bone marrow-impregnated collagen matrix. Given lower invasiveness, the PRP-impregnated collagen matrix would have advantages in clinical use.

[Sibling cases of severe infantile form of nemaline myopathy with ACTA1-gene mutation].

Severe infantile form of nemaline myopathy is clinically characterized by marked muscle hypotonia and weakness with respiratory and feeding difficulties since infancy. Recently, mutations in the skeletal muscle alpha-actine gene (ACTA1) have been identified in many patients with the nemaline myopathy. We experienced two cases of severe infantile form of nemaline myopathy with ACTA1 mutation (missence heterozygous mutation;c.553C>T, p.R185C) in siblings presenting with different clinical symptoms and courses. The elder brother was a typical "floppy infant" at birth. Because he could not suck and swallow at all, he was fed completely through a nasogastric tube. At 2 months of age, he developed respiratory insufficiency and was placed on a respirator all day. He was diagnosed with having nemaline myopathy from his muscle biopsy, which revealed marked variation in muscle fiber size with large numbers of nemaline bodies on Gomori-trichrome stain. In contrast, the younger brother presented with mild muscular hypotonia and feeding difficulty during the neonatal stage;therefore, he was partly fed through a nasogastric tube. At 2 months of age, he was admitted to our hospital because of respiratory distress, and he required nasal continuous positive airway pressure with oxygen followed by noninvasive positive pressure ventilation intermittently, mainly at night. He was followed at his home by parents with no serious problems;however he unexpectedly died at the age of 15 months. Although most cases of severe infantile form of nemaline myopathy caused by ACTA1 mutations are sporadic and have no family history, we emphasize that clinical symptoms are variable in siblings with the same mutation.

Preservation of the properties of elastic plasma protein plus platelet film for wound dressing.

Experimental results have previously been reported for a new biological dressing consisting of concentrated plasma proteins and platelet-rich plasma (PRP), which is named Platelet-Protein film (PPF). Based on the results of this experimental study, a clinical trial was begun to examine the usefulness of PPF. Although fresh autologous PPF is being used in the clinical trial, it is considered that the use of a preserved material prepared in advance would enable more convenient application. To verify the usefulness of preserved PPF, this preliminary study was conducted to examine the effects of fresh PPF, preserved PPF or blood clot, as control, applied to excisional skin defects in healing-impaired mice. The wound area and vascular density were analysed on day 9 after wound creation. Significant decrease of the wound size was observed in the preserved PPF and fresh PPF groups (4.2 (3.7), 2.2 (0.53)%) in comparison with that in the control group (38.5 (18.6)%, p < 0.05). Furthermore, a significant increase of the vascular density was also observed in the preserved PPF and fresh PPF groups (0.055 (0.021), 0.050 (0.019) mm(2)/mm(2)) as compared with that in the control group (0.016 (0.010) mm(2), p < 0.01). There was no significant difference in the effect on the wound size or vascular density between the preserved PPF and fresh PPF groups. The results showed that the properties of PPFs could be maintained for at least 1 week under appropriate storage conditions. The possibility of preservation of PPF for future use could be of practical advantage in actual clinical situations.

[Case of delayed awakening after remifentanil leakage out of a vein].

We report a case of delayed awakening with characteristic repeated loss of consciousness after remifentanil infusion complicated by leakage from an intravenous catheter. A 30-year-old male underwent microlaryngeal surgery for a vocal cord polyp. During anesthetic induction, infiltration from an intravenous (IV) line in the left forearm was observed 10 min after initiating a continuous infusion of remifentanil 0.5 microg x kg-1 x min -1. A second peripheral IV catheter was placed in the right forearm and general anesthesia was induced with remifentanil infusion at 0.3 microg x kg-1 x min- 1, propofol 120mg, fentanyl 100 microg, and rocuronium 70 mg. Anesthesia was maintained with remifentanil 0.05-0.3 microg x kg-1 x min -1and sevoflurane (1.5% in oxygen) for the 4 min of surgery. A few minutes after tracheal extubation, the patient developed respiratory arrest and loss of consciousness. We immediately ventilated him with a bag-valve-mask and administered naloxone 0.04 mg. Thereafter, he repeatedly awoke and was drowsy three times over the next 5hr. It was followed by an uneventful postoperative period. No remarkable deficit was observed in the patient. Blood gases, electrolytes, glucose values, and body temperature were within normal ranges throughout the perioperative period. Brain computed tomography, mag- netic resonance imaging, and electroencephalography showed no abnormalities. It was considered that the incidental subcutaneous remifentanil accumulation may have caused the respiratory suppression and delayed awakening.

Study of continuous irrigation negative-pressure treatment using an original ulceration model.

A continuous irrigation with intermittent aspiration (CIIA) method has previously been developed in the treatment of infected expander sites. For the purpose of treatment of infected wounds, a new intermittent negative pressure irrigation treatment (INPIT) has been developed that is a combination of CIIA with topical negative-pressure therapy. This study aims to investigate the efficacy of INPIT. The efficacy of irrigation was investigated by changing the conditions including the location and the number of irrigation tubes, flow volume, and the timetable of negative-pressure application using original ulcer models. Although the presence of side holes and increase in the number of tubes or flow volume improved the irrigation efficacy, non-washed-out areas remained. On the other hand, INPIT allowed more uniform and wide area washing even at low flow volume. The results suggest that INPIT is superior to general conventional continuous irrigation treatment in irrigation efficiency.

Treatment of chronic ulcer with elastic plasma protein and platelet film for wound dressing.

Experimental results have previously been reported for a new biological dressing consisting of concentrated plasma proteins and platelet-rich plasma (PRP), which is named Platelet-Protein film (PPF). This study reports clinical experience using PPF produced from the patients' own blood by the original technique. Ten patients with chronic wounds underwent PPF treatment and evaluated the transcutaneous oxygen tension (TcPO2) and vascular density. Eight of the 10 patients received a split-thickness skin graft on induced granulation tissue and have remained free from complications for more than 12 months since treatment. The TcPO2 values significantly increased at 4 days after treatment (before 38.4 (14.1) mmHg, after 55 (19.9) mmHg, p < 0.01). The vascular density at the ulcer base increased at 14 days after treatment in all the cases. The results showed that PPF has the potential to enhance chronic wound healing.

Treatment of venous ulcers with bone marrow-impregnated collagen matrix.

Bone marrow attracted our attention as a potentially beneficial material for the treatment of wounds, because it contains multipotential progenitor cells and produces growth factors. We impregnated autologous bone marrow cells on to a collagen matrix that had been used for the treatment of chronic wounds. The bone marrow-impregnated collagen matrix was then as a biomaterial scaffold for the treatment of wounds. This study was designed with the aim of clinically evaluating the effects of bone marrow-impregnated collagen matrix on wound healing of venous ulcers. We applied the matrix in 15 patients with chronic venous ulcers, and evaluated the transcutaneous oxygen tension (TcPO(2)) and vascular density. The application of the matrix induced healthy granulation tissue. All patients were given a split-thickness skin graft on to the induced granulation tissue, and have remained free from complications for more than eight months since the treatment. The mean (SD) vascular density at the ulcer base increased after the treatment (before 0.011 (0.006) mm(2)/mm(2), after 0.064 (0.036) mm(2)/mm(2), p < 0.001). The periwound TcPO(2) values tended to increase (before 17.1 (12.7) mmHg, after 30.6 (13.4) mmHg, p < 0.001). Our results have shown the efficacy of bone marrow-impregnated collagen matrix for the treatment of intractable venous ulcers.