Sterile Foam Research Articles

The nasal microbiome of predicting bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity and may cause substantial long-term disabilities. To characterize and compare the nasal swabs microbiome of early stage in premature infants and determine whether microbial diversity or composition in the nostrils associated with BPD disease. We performed a prospective observational cohort design. Preterm neonates less than or equal to 30 weeks of gestation were recruited from NICU, Children's Hospital, Zhejiang University School of Medicine from 2019 to 2020. Sterile foam swabs were collected from anterior nares at 1 and 3 weeks of postnatal age. We used PCR amplification and 16S rDNA sequencing. Neonatal demographic data including gestational age, birth weight, medication administration history and discharge outcomes were recorded. A total of 49 nasal swab samples were collected from 28 premature infants. Thirteen infants with BPD and 15 controls were finally involved in the study. Birth weights ranged from 700 to 1550 g. Gestational age ranged from 252/7 to 30. We found increased in the expression of Prevotella and decreased of Caulobacter in BPD group at both times. Prevotella and Caulobacter were correlated with the severity of BPD (Spearman r = 0.551, r = − 0.545; P = 0.00005, 0.00006; respectively). Receiver operating characteristic analysis showed that the area under characteristic curve of Caulobacter model at first week reached 0.821 and Prevotella model at third week was 0.796. Moreover, microbial functional prediction analysis revealed that ABC-type transports were distinctively changed in BPD group. In summary, the use of non-invasive nasal swabs of microbiome to explore the pathophysiology in BPD is a compelling method worthy continuing to expand and research.

Creation of a novel inflatable vaginal stent for McIndoe vaginoplasty

To describe how to create an inflatable vaginal stent for use in McIndoe vaginoplasty that can be constructed using standard operating room supplies. Step-by-step video instructions that demonstrate how to construct and use an inflatable vaginal stent. (This video article was exempt from institutional review board approval.) SETTING: Academic hospital. A woman presenting with vaginal agenesis requiring a McIndoe vaginoplasty for the creation of a neovagina. A novel inflatable vaginal stent compliant with operating room procedures that is radio-opaque, functional, and can be used for patients with or without a functional uterus. The device is modeled after the effective inflatable vaginal stent that was previously commercially available but is no longer produced. Although a vaginal stent may be created in the operating room by placing surgical sponges inside a sterilized condom, many operating rooms have restrictions on equipment that can be brought into the operating room and special criteria for how to sterilize this equipment, and there are also restrictions against leaving non-radio-opaque objects "inside" the patient. The novel inflatable vaginal stent we have developed has multiple advantages compared with a rigid dilator: it is deflatable, so it does not cause trauma or interrupt the delicate tissue graft during insertion, removal, or repositioning; it is firm enough to conform and circumferentially press the tissue graft against the dissected vaginal space but is soft enough to decrease the risk of pressure necrosis or damage to the urethra; and it has a drainage port to prevent the buildup of a fluid pocket that could interfere with graft adherence. Our stent incorporates all these unique properties and can be easily constructed using sterile operating room supplies. The construction of this device requires a silicone Foley catheter, sterile foam sponges from a vaginal prep kit, a sterile radio-opaque sponge, a sterile vaginal ultrasound probe cover, a long Kelly, a 60-cc catheter tip syringe, a ruler, scissors, 0-vicryl suture, and sterile gloves. Effectiveness of a self-made inflatable vaginal stent using standard operating room supplies that meets operating room protocol standards. A standard dose of prophylactic antibiotics should be administered preoperatively to prevent surgical site infection. After placement of the tissue graft in the dissected neovagina cavity, the vaginal stent is placed and slowly inflated to circumferentially apply the tissue graft against the dissected vaginal space. The stent remains in place for 7 days and then should be removed in the operating room to allow for an examination under anesthesia, which provides the ideal setting to best evaluate the initial graft adherence. After careful inspection of the neovagina and tissue graft, a standard silicone vaginal mold is placed to maintain vaginal patency and prevent stricture of the tissue graft. The silicone mold should remain in place continuously until complete graft adherence occurs (approximately 4 to 6 weeks), and then it can be worn nightly until the patient is regularly sexually active. If at any point the patient discontinues nightly use of the silicone mold before regular sexual activity, vaginal stricture and a decrease in vaginal caliber will occur. Our novel inflatable vaginal stent is useful to surgeons performing a McIndoe vaginoplasty for vaginal agenesis with or without a uterus. It is compliant with operating room protocols and restrictions, as it is constructed from operating room supplies and is radio-opaque. Moreover, it is adjustable in size and effective in applying circumferential pressure for graft adherence. When used for segmental vaginal agenesis, the Foley catheter may be advanced through the cervix, then the balloon can be inflated, to stabilize the position of the stent during the first week postoperatively. The main limitation of this device is that it must be constructed by the surgeon, but the advantage of self-constructing the stent is that the size and shape can be tailored to conform to each individual patient. We prefer this inflatable vaginal stent to a rigid vaginal dilator in the first week of tissue healing to allow for easy insertion and removal of the stent without disrupting the tissue graft, to help prevent tissue necrosis, and to provide a fluid drainage port during graft adherence. We recommend this device as an ideal option for surgeons to consider when performing a McIndoe vaginoplasty.

Smile - Secure my intravenous line effectively: A pilot randomised controlled trial of peripheral intravenous catheter securement in paediatrics

AimEvaluate the feasibility of an efficacy randomised control trial (RCT) of paediatric peripheral intravenous catheter (PIVC) securement to prevent failure without resultant skin damage. MethodsA 3-arm, pilot RCT in an Australian paediatric hospital. Random assignment of 330 children to receive (i) bordered polyurethane dressing (BPU) + non-sterile foam (NSF), (ii) integrated securement dressing (ISD) + sterile foam (SF), or (iii) tissue adhesive (TA)+ NSF. Primary outcomes were feasibility and PIVC failure. Secondary outcomes included: skin/bloodstream infection; occlusion; infiltration; dislodgement; phlebitis; dwell; serious adverse events; acceptability and microbial colonisation of catheter tips, wound site, and foam. ResultsMost feasibility outcomes were confirmed; 98% of eligible patients consented, 96% received their allocated dressing and no patients were lost to follow up. Eligilbility feasibility (58%) was not met. 11 randomised patients did not require a PIVC. Of 319 patients receiving a PIVC (20,716 PIVC-hours), a significant reduction in PIVC failure was demonstrated with ISD, 31/107 (29%, p = 0.017) compared to BPU, 47/105 (45%). Although not statistically significant, compared to BPU, TA 34/107 (32%, p = 0.052) was associated with less PIVC failure. On Cox regression, no securement intervention significantly reduced PIVC failure. Older age (HR 0.92; 95% confidence interval [CI] 0.88–0.96; p = <0.01), no infection at baseline (HR 0.51; 95% CI 0.34–0.78) and insertion by vascular access specialist (HR 0.40; 95% CI 0.26–0.64) were significantly associated with reduced failure (p < 0.05). ConclusionISD and TA had reduced PIVC failure compared to BPU. A large efficacy trial to test statistical differences is feasible and needed.

Formation of local protection of the respiratory tract in Holstein calves

The processes of formation of the local protection of the respiratory tract in nasal secretion samples of Holstein calves from birth to 6 months of age that were born from clinically healthy cows were examined. Only clinically healthy animals were involved in the experiment. Nasal secretion samples were collected with the help of a sterile foam tampon with a fixing thread in order to assess local immunity in animals at the age of 1, 5, 10, 30, 60, 90, 120, 150, and 180 days. Total protein, mucin, lysozyme activity, and alkaline phosphatase (ALP) were determined using commercially available methods. The amounts of immunoglobulins were studied using disk electrophoresis in polyacrylamide gel with commercial marker proteins. Studies have shown that the primary potential of local protection of the respiratory tract is formed during intrauterine development. The main factors of primary potential are mucin, lysozyme, alkaline phosphatase, and secretory immunoglobulins of classes A (SIgA) and M (SIgM), which provide safety of adaptation in newborns to the new conditions of existence. There is a decrease in mucin level by 47.3% (P < 0.001), in SIgA by a factor of 6.7 (P < 0.001), and in SIgM by a factor of 6 (P < 0.001) during the first week of life. However, the risk of immunodeficiency is mitigated by the preservation of relatively high levels of lysozyme, ALP, and IgG, creating optimal conditions for the processes of formation of respiratory functions in young animals during the first 2 months of life. After that, SIgA increases by 70% (P > 0.05) at the age of 60 days and mucin level increases by 56.7% (P < 0.001) between 2 and 6 months.

Role of vacuum assisted suction drainage in management of deep sternal wound infection: Experience in one center

BackgroundDeep sternal wound infection (DSWI) is a life threatening complication of a median sternotomy. This study was conducted in Zagazig University Hospital in the period from Marsh 2014 to September 2016, to evaluate use of vacuum (VAC) in treatment of DSWI. MethodsTwelve patients with DSWI out of 840 median sternotomy procedures for coronary artery bypass graft (CABG), valve replacement, valve repair, adult congenital heart disease and mediastinal tumors which needed median sternotomy were collected; Radical debridement of the wounds was performed; sterile foam with drain was placed in the wound which was covered with sterile OPSITE dressing; the drain being connected to a suction unit maintaining −100 mmHg pressure except wounds in which the cardiac surface directly touches the device we used minimum low negative pressure of −50 mmHg because of the fear of hemorrhage and impairment of cardiac function.Follow up for 3–6 months after vacuum therapy was done to detect any morbidity or recurrence. ResultsPatients with DSWI in our study were managed with this therapy. They were twelve patients. 7 were males and 5 females. Mean age was 66 years. Excellent wound healing occurred in eleven patients (91.7%), with no mortality while one patient (8.3%) had relapse (multiple sinuses appeared). This patient had multiple risk factors. The organisms isolated from his wound were Staphylococcus epidermis, Pseudomonas aeruginosa and Candida albicans. This patient required omental flap to fill the defect after radical debridement of the wound combined with a VAC therapy system and intravenous antifungal therapy, these led to this patient's favorable outcome. ConclusionsThe incidence of DSWI was similar in our center to that in other cardiothoracic centers. Various risk factors were found to be associated with DSWI. The DSWI pathogens in our center are similar to those in other reports most of our patients were treated successfully with this technique with excellent wound healing. So, vacuum therapy is safe and effective method for treating DSWI.

Foam padding in casts accommodates soft tissue swelling and provides circumferential strength after fixation of supracondylar humerus fractures.

Varying casting techniques are used after surgical treatment of pediatric supracondylar humerus fractures. The goals are to maintain fracture reduction, while accommodating soft tissue swelling and minimizing the risk of compartment syndrome. A retrospective chart review of consecutive patients aged 0 to 14 years who underwent surgical treatment of supracondylar humerus fractures over a 9½-year period at a pediatric trauma center was performed. A new method of casting, in which one half inch sterile foam is applied directly to the skin and overwrapped by circumferential fiberglass, is presented and compared with traditional casts. A total of 541 consecutive patients were included. Foam had been used in 35% (190/541) of patients. Foam was used significantly more frequently in Gartland type 3 fractures (133/314 patients, 42%) than in type 2 fractures (57/227 patients, 25%) (P<0.001). Foam was also used more often in patients with preoperative neurovascular deficits (34/57, 60%) than in those without (156/484, 32%) (P<0.001). No patient in either group developed compartment syndrome postoperatively. Both patients in the study who required revision closed reduction and pinning were casted without foam, and one of these casts had been split. Reoperation was not associated with cast splitting (P=0.216) or foam use (P=0.543). For postoperative immobilization of supracondylar humerus fractures we present a new method of placing foam directly on the skin, followed by circumferential fiberglass casting. This method offers the theoretical advantage of the strength of a circumferential cast, plus the benefit of allowing for swelling. Although the novel foam and cast combination was used in more severe fractures, results were comparable to traditional casts and may reduce the need for cast splitting. Therapeutic-Level III.

Combined Endoscopic Transanal Vacuum-Assisted Rectal Drainage: A Novel Therapy for Colorectal Anastomotic Leak after TME for Cancer

Introduction: Low colorectal and colo-anal anastomosis leakage after anterior resection of rectum occurs in up to 24% of cases. Leak is the main cause of morbidity and mortality in postoperative period and can result in a permanent stoma in up to 25% of cases. Loop ileostomy or colostomy does not reduce the percentage of fistulas, but reduces flow rate. Conservative management imply long times to heal. Endosponge® system (B. Braun Aesculap AG, Germany) was recently acquired in clinical practice. This system accelerates healing process through vacuum creation, removal of fluids and edema, infection control, local increase of blood flow and stimulation of granulation tissue formation. The device consists of a cylindrical polyurethane sponge, with 400 to 600 micron pores, standard dimension of 7 cm, which can be cut to fit the estimated size of the abscess cavity. The drain tube is connected to a Redyrob Trans Plus®bottle which exerts a constant suction during the therapy. Materials and Methods: From November 2012 and March 2014 four patients were treated with Endosponge® system, all of them underwent operation of anterior resection of rectum for cancer and developed anastomotic leakage during postoperative course. All patients had loop ileostomy, none presented signs of sepsis. The Endosponge® system was then placed endoscopically. In all cases, after the first placing, the authors utilized sterile foam dressing from negative pressure wound therapy kit, tailored to better fill the abscess cavity and connected with Redyrob Trans Plus?bottle. Device changes were performed every 5 - 7 days, according to the size of the cavity and the amount of secretions produced. The treatment was started during hospitalization first and then continued as outpatient. Results: There was no mortality. The amount of secretions was related to the initial size and the degree of contamination of the abscess cavity. Antibiotic therapy was discontinued after an average of 21 days, with a range between 14 and 32 days. Complete healing was achieved in a median of 82 days (30 to 148) in all patients with good functional results, no further surgery was required. Conclusions: The results of therapy with Endosponge® seem encouraging. Success of therapy is higher if initiated as soon possible after the intervention and is also related to the size of dehiscence and abscess cavity. In cases with large abscesses, it is not clear whether this new treatment leads to reduction in healing time, however, can prevent the packaging of a (often definitive) colostomy. Further studies will be able to select patients who will most benefit from the procedure.

Improvising Vaginoplasty Using Fibrin Glue with Vacuum Expandable Condom Mold

Background: Innovations in vaginoplasty aim at creating a cosmetically and functionally near normal vaginas with minimal morbidity. One such innovation is the use of fibrin glue to fix the graft in a neovagina. It is simple, effective, not time consuming, and leads to better hemostasis and tissue apposition. Additional use of a vacuum expandable mold can further improve the outcome. Case: A 25-year-old married woman presented with primary amenorrhea and coital difficulty. Examination revealed normal secondary sexual characters and absent vagina. Ultrasound confirmed absent uterus and vagina, and normal ovaries. With the diagnosis of Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome having been made, McIndoe vaginoplasty was planned. A split thickness skin graft was taken from the thigh. A vaginal mold was created by using sterile foam with a rubber tube in the center and covered by condom. After spreading the graft over the mold, the edges of graft were approximated using fibrin glue, instead of conventional use of sutures, and glue was applied over rest of the graft. The diameter of the mold could be decreased by creating negative pressure in the rubber tube, which helped in its easy placement in the neovagina. The mold was removed on the 7th postoperative day. Results: The cavity was inspected and the graft appeared to be taken up well. The patient was able to lead a normal sexual life. Conclusions: The use of fibrin glue with a vacuum expandable mold in vaginoplasty appears to be promising. (J GYNECOL SURG 29:265)

Curativo à vácuo para cobertura temporária de peritoneostomia

The advances in patient care with trauma or severe intra-abdominal infections, brought important gains in survival with the use of peritoneostomies. But the management of patients brought a difficult problem: the primary closure without tension of the abdominal cavity. To present a proposal for temporary coverage of peritoneostomies in patients undergoing damage control laparotomy or decompressive laparotomy for abdominal compartment syndrome. Isolation of the small intestine loops from abdominal internal; coverage of the intestinal surface with a polyethylene film multiperforated with sterile scissors or scalpel blade, to prevent direct contact with the foam. It is placed below the edges of the defect between the parietal and visceral peritoneum. Over it, a polyurethane sterile foam is fixed to the edges, leaving the defect tension free to the vacuum be applied. Another coverage with a plastic adhesive polyester impregnated with iodine stuck to skin is done, and, at the end, is added a drainage continuous aspiration system. The dressing is changed between three and five days. It was used successfully in four patients with primary closure of the abdominal cavity after seven to 21 days. Of these, three had open abdomen after laparotomy for trauma (two due to damage control and one for lack of primary closure); the fourth had been previously submitted to decompressive laparotomy for abdominal compartment syndrome. The vacuum dressing proved to be good choice for temporary coverage of peritoneostomies allowing faster closure of the abdominal wound, reducing the number of reoperations and providing protection against bacterial contamination of the intestinal loops.

Use of Improvised Vaccum Assisted Suction Drainage for Cases of Deep Sternal Wound Infection

To devise a simple, cheap and effective improvised method of treating deep sternal wound infections (DSWI) by negative pressure obviating high cost of patented systems. Records of ten post CABG patients operated via median sternotomy approach over a two and half year period and treated for DSWI were analysed. Sterile foam with drain was placed in the wound, which was covered with Ioban (Steridrape), the drain being connected to a suction unit maintaining 100mmHg pressure (<$12 cost). Ten (10) patients of DSWI were managed with this therapy. Mean age was 60.4 years. Pseudomonas found in 1 (10%), Acinetobacter and Pseudomonas in 1 (10%) with Escherichia coli in 1 (10%). Five (50%) patients had diabetes mellitus. Mean hospitalisation period was 43 days. Seven (70%) patients underwent secondary suturing. Two (22%) patients had relapse, which was managed with dressings and secondary intention suturing. One patient who underwent a muscle flap cover had major recurrence with multiple sinuses. Excellent wound healing in 9 (90%) patients with no (0%) 90-day mortality. Improvised components can be safely employed to provide effective negative pressure therapy for DSWI with excellent results.

An Innovative, Cost-Effective, Negative Pressure Device for Management of Bedsores in Traumatic Paraplegia

Introduction Management of bedsores in traumatic paraplegia has been a challenge since time immemorial. Conventional serial debridement and dressings require prolong hospitalization, imply posible complications and are an economic burden. Modalities like hyperbaricoxygen, electrical stimulation, altered cultured keratinocytes are cumbersome, expensive, and not readily available. Negative pressure to promote wound healing is under evolution. This study evaluates the effect of negative pressure in bedsore management. Methods The Negative Pressure Device (NPD) included sterilized foam, a low power continuous suction apparatus (Romovac) and a transparent polyurethane adhesive dressing. NPD was exclusively a bedside procedure. The perforated end of a drainage tube was placed on the wound surface and other end exited 10 cms away from wound margin, connected to Romovac. Sterilized foam was trimmed to size and geometry of wound as cover. Opsite closed the wound with an airtight seal. The bellow of Romovac was charged to attain negative pressure. Recharging was done after five to six hours. The wound inspected and dressings changed every five to seven days. Results NPD converted an open wound into a close controlled wound. By drawing away fluid from the wound it prevented collection of secretions and decreased purulence. Negative pressure increased vascularity, enhanced granulation tissue and rapidly reduced the size and depth of wound. Airtight sealing prevented soiling and odor enabling universal acceptance. In controlled based study, NPD: Reduced the frequency of dressing from once daily to once in five to seven days (cost effective). Reduced bacterial contamination and substantially increased granulation tissue. Serial microbial assessment of wound revealed efficacy in controlling bacterial growth and achieving a sterile culture within 10 days. Prooved itself to be an efficient and painless method of serial debridement. Reduced wound size and depth to one third of the original within three weeks. Was well tolerated by patients. The drawbacks of NPD were: Failure in low sacral bedsores close to the natal cleft. Difficulty in getting an airtight seal using Opsite. The tendency of the sterile foam to disintegrate, making the secretions viscous and clogging the drain. Tendency to increase bleeding, during changes of dressings, from the exuberant granulation tissue which formed. Conclusions NPD is a bedside procedure, easy to apply, with minimal side effects. It reduces the frequency of dressings and duration of hospitalization. By converting an open wound into a close-controlled wound it decreases purulence, hastens recovery and prevents soiling and the characteristic odor. The NPD apparatus suggested is innovative, cost-effective.

Melanopsin-Expressing Retinal Ganglion Cells Are More Injury-Resistant in a Chronic Ocular Hypertension Model

To investigate the survival of melanopsin-expressing retinal ganglion cells (mRGCs) after the induction of chronic ocular hypertension. Intraocular pressure (IOP) was elevated in adult Sprague-Dawley rats using an argon laser to photocoagulate the episcleral and limbal veins. IOP was measured with a calibrated tonometer and monitored for a period. Seven days before the animals were killed, a piece of sterile foam soaked with gold fluorescent dye was placed onto the superior colliculus (SC) to label the SC-projecting retinal ganglion cells (scRGCs) retrogradely. mRGCs were visualized by free floating immunohistochemistry on whole-mounted retinas. The number of surviving scRGCs and mRGCs were counted on flatmounted retinas. The branching pattern of dendrites and soma size of mRGCs were examined. An approximately 1.7-fold increase of IOP and a significant loss of scRGCs were found in experimental eyes after laser photocoagulation. However, no significant cell loss or morphologic changes on mRGCs and their dendrites after the induction of chronic ocular hypertension are noticed over a 12-week period. Although the degeneration of retinal ganglion cells (RGCs) is a major concern in glaucomatous damage, the findings show that mRGCs are less susceptible to death after the induction of chronic ocular hypertension. This result indicates that mRGCs carry some unique properties that are different from those of other subpopulations of RGCs. The immunohistochemistry approach can be used to distinguish easily these mRGCs from other subtypes. This method provides a useful tool to investigate their injury-resistant properties that are informative for the development of effective neuroprotective treatment for glaucoma.

The K247R Substitution in ABL Tyrosine Kinase Domain Is Not a Mutation Leading to Imatinib Resistance but a Polymorphism Rarely Present in CML Patients and in Normal Subjects.

Abstract The major mechanism for resistance to imatinib mesylate (IM) is the onset of ABL point mutations altering functional inhibition of the tyrosine kinase activity by IM. Biochemical, cellular assays and clinical studies have demonstrated that different BCR-ABL mutations exhibit various degrees of resistance, and mutations occurring in the ATP-binding loop may be correlated with subsequent disease progression. In this study, we investigated the status of the K247R ABL polymorphism and correlated it to disease outcome. Patients and methods: Two patients (P1 and P2) were diagnosed with CML based on peripheral blood findings, karyotyping analysis (showing t(9;22)(q34;q11)) and molecular analysis for BCR-ABL (indicating M-BCR fusion transcripts) in 2,000 and 1,994, respectively. P1, a 54 years old male, enrolled in the Novartis IRIS study, was randomly assigned to the interferon + AraC arm after informed consent. The patient achieved a complete hematologic remission (CHR) at 3 months and a complete cytogenetic response (CCR) at 24 months. At time of cytogenetic relapse (2 years later), P1 had never received IM which was introduced in April 2,005. P2 received IM (400mg to 600mg/day) during 82 months and had shown only CHR during 14 months with no MCR. Epithelial cells were collected in the mouth through sterile foam tipped applicators for both patients. DNA was obtained from blood samples of 232 individuals, including 124 patients with CML, 72 patients with acute myeloid leukemias (AML) and 36 normal healthy donors. The K247R change was studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique (AluI restriction enzymatic site abolished) and was confirmed by direct sequencing. Results: Both patients, showing the K247R substitution located close to the P-loop, were retrospectively investigated during disease progression. We found that this change accounted for 100% of the BCR-ABL transcripts at CML diagnosis (and in all the further samples) for P1 (no material was yet available from P2 at this time) and for 50% of the ABL gene in extracted DNA from epithelial cells in the 2 patients. P1, despite of the K247R substitution received IM (400 mg/day) and achieved a CHR, a CCR and a good molecular response (one log reduction after two months of IM). IM resistance observed in P2 was probably due to the presence of an additional F317L mutation, known to induce a very strong resistance to IM. The F317L mutation accounted for 100% of the BCR-ABL transcripts at the resistance, was absent in DNA from epithelial cells. The screening showed the K247R exchange in 1 normal subject (heterozygote), in 2 CML patients (P1 and P2: at heterozygous state in normal cells and at homozygous state in BCR-ABL transcripts) and in none AML samples. According to that, the incidence of this polymorphism seems to reach nearly 1 to 1.5%. Conclusion: This study demonstrates that the K247R substitution in ABL tyrosine kinase domain is not a mutation leading to IM resistance but only a rare polymorphism. Detailed analysis of this polymorphism status will be reported.

Effects of Vacuum-assisted Closure on Wound Microcirculation: An Experimental Study

To study the mechanism through which vacuum-assisted closure (VAC) induces an increase in blood flow and reduces oedema on skin wounds. Thirty-two Japanese large-ear white rabbits were used. A round full-thickness skin defect (retaining the perichondrium), 2 cm in diameter, was created on each dorsal ear. The wound on the left ear was assigned to the experimental group, and the wound on the right ear to the control group. In the experimental group, the sterile foam dressing was trimmed to the appropriate size and geometry for the given wound and placed into the wound defect. The surface of the wound containing the foam dressing was covered with an adhesive drape to create an airtight seal. Afterwards, negative pressures of -5, -10, -15 and -20 kPa were exerted on the same wound, each lasting for 20 minutes, at intervals of 10 minutes. In the control group, the wound was treated with petrolatum gauze only. At different time points, the microcirculation microscope and image pattern analysis were used to observe the variation in wound microcirculation through a detective window. It was found that VAC promoted capillary blood flow velocity, increased capillary calibre and blood volume, stimulated endothelial proliferation and angiogenesis, narrowed endothelial spaces, and restored the integrity of the capillary basement membrane. By increasing capillary calibre and blood volume and by stimulating angiogenesis, VAC could improve blood circulation in wounds. By narrowing endothelial spaces and by restoring the integrity of capillary basement membranes, VAC could decrease the permeability of blood vessels and wound oedema.

Patient with compartment syndrome of the lower extremity

J Vasc Nurs 2003;21:24-9.

Patient with compartment syndrome of the lower extremity

Case Situation A 54-year-old man was admitted to our hospital for treatment of compartment syndrome of the left lower extremity. He gave a history of sustaining a puncture wound from an injection of equine steroid to his left medial thigh. He immediately felt pain and noted pallor in the left lower leg, and the extremity soon became edematous. He went to his local emergency department, was treated with an oral steroid dosepak, and was released. The pain and edema increased during the next 2 days, and the patient came to our emergency department with mottling of the left lower leg, severe pain, edema, and numbness of his toes. The patient’s dorsalis pedis and posterior tibial pulses were not palpable but were audible with a Doppler. The Doppler ultrasound showed no deep venous thrombosis or arterial injury but did show compression of the popliteal and tibial veins because of severe swelling of the left calf. The arterial component of the Doppler ultrasound was not completed because of severe leg pain. The anterior lateral compartment pressure was 100 mm Hg, and the medial compartment pressure was 99 mm Hg. Pressures from 40 to 80 mm Hg sustained for 12 hours or more can cause significant muscle necrosis and permanent neurologic changes.1 The patient’s serum glutamate oxaloacetate transaminase level was 1386 (normal, 0-37), his serum glutamate pyruvate transaminase level was 590 (normal, 0-40), and his white blood cell count was 21,160 (normal, 3.5-11,000). The patient was given cefazolin (Kefzol), 1 gm intravenously every 8 hours for 6 doses, and intravenous morphine sulfate for pain management. Phillips1 defined the pathophysiology of compartment syndrome as an insult to normal local tissue homeostasis that results in increased tissue pressure, decreased capillary blood flow, and local tissue necrosis caused by oxygen deprivation. Physical signs of acute compartment syndrome are extreme pain out of proportion to the injury, pallor of the extremity, and paresthesia. Passive stretch of the muscle causes increased pain. Muscle weakness, paralysis, and an absent extremity pulse are late findings. When compartmental pressures are greater than 30 mm Hg in the presence of clinical findings, the recommended treatment is to perform a fasciotomy to decompress the leg compartments. The prognosis is good when a fasciotomy is performed 25 to 30 hours after onset. After the third or fourth day, a fasciotomy may be contraindicated because severe infections can occur in the necrotic muscle.1 The patient underwent medial and lateral fasciotomies of the left lower extremity and debridement of necrotic tissue. The orthopedic surgeon ordered that the wounds be packed with dressings moistened with 0.25% Dakin’s solution. The dressings were changed at least every 4 hours because of copious amounts of serosanguineous drainage. The patient’s bed linens were often saturated. The dressing changes were painful, and each change took 30 minutes. Foot drop was already present, and a splint was used for treatment. A plastic surgeon and the WOC nurse were consulted for wound care recommendations. Linda Wessel, BSN, RN, CWOCN: Following debridement by the plastic surgeon, the medial and lateral wounds measured 32 cm and 30 cm in length and 8 cm in width. Extensive ecchymosis was present in the periwound tissue, and tendons were exposed in both wounds (Figures 1 and 2). Because of the copious amount of serosanguineous drainage, the need to reduce edema, and the need to promote granulation tissue, it was decided to treat the wound with the Vacuum Assisted Closure (VAC) system (Kinetic Concepts, Inc, San Antonio, Tex). The VAC system uses a sterile foam dressing connected to a suction pump that applies negative pressure to the wound. The negative pressure removes wound debris, fluid, and bacteria. It increases tissue perfusion, thus promoting granulation of the tissue.2 The foam dressing is placed in the wound and secured with an occlusive film dressing that decreases bacterial contamination.3 Figure 3 shows the medial calf wound with the VAC dressing in place. The suction canisters are either stationary or portable and can be handled easily by the nursing staff. Pain medication was administered prior to the VAC dressing change if needed. Supplies listed in the Box were used. Universal precautions were followed. The dressing tubing was clamped and disconnected from the canister tubing. Allkare Adhesive Removal Wipes (ConvaTec, Princeton, NJ) were used to help loosen the film dressing. Sterile normal saline solution was Linda C. Wessel, BSN, RN, CWOCN, is Patient Educator and Consultant for the Wound Care and Hyperbaric Medicine Center, Southeast Missouri Hospital, Cape Girardeau, Missouri.

Vacuum-Assisted Wound Closure

E dwina Paolo, 68, is hospitalized with a nonhealing saphenous vein donor site on her left leg three months after a coronary artery bypass graft. The distal portion of her wound is covered with fibrin, and bone is exposed. After several weeks of traditional wound care and moist dressings, vacuumassisted closure (VAC) therapy is initiated to prepare the wound bed for a skin graft. The nurse caring for Ms. Paolo cuts a piece of sterile polyurethane foam sponge to fit the wound cavity. She places a tube with end and side ports inside the sponge and connects it to a disposable canister loaded into a programmable vacuum pressure pump.1.2 She covers the foam dressing and the embedded evacuation tube with a transparent film to hold the sponge and tubing in place, to ensure an airtight seal and to maintain a moist environment. X Negative suction pressure-pressure lower i than that of the atmosphere at sea level-is applied by the VAC pump at 75 mmHg, increasing in increments of 25 mmHg (to prevent pain during therapy) to a target pressure of 125 mmHg. The device can be programmed to deliver an amount of negative pressure appropriate to a patient's comfort level and the characteristics of the wound. Continuous negative pressure is applied for 48 hours; then the sponge is changed and treatment is continued. For two weeks, Ms. Paolo receives therapy with intermittent negative pressure-suction is turned on for five minutes and off for two minutesto remove excess fluids, promote formation of granulation tissue, and restore capillary flow.

Development of a sterile cultivation system for rooting of shoot tip cultures (red raspberries) in duroplast foam

In order to improve the availability of oxygen for shoot tip cultures during the course of rooting and to overcome some further agar-related problems a sterile foam cultivation system was developed. Three commercially available foam substrates have been tested, but only a wide pore phenol resin foam proved to be useful in the rooting of red raspberry shoots ( Rubus idaeus cv. ‘Gigant’). In comparison to root growth in agarous medium, the newly developed foam cultivation system improved the ramification of the root system, increased the number of root hairs significantly and reduced the friability (lignification) of roots. Also shoot length increased significantly. From the growth experiments it can be concluded that the chemical rather than physical properties of the foam substrate are growth limiting. Still some efforts must be made to improve and standardize the properties of the foam substrate for routine use in mass propagation of organ cultures in vitro.

Exposure treatment of burns

LTHOUGH exposure of a burnt surface is not a modern concept, it has only become widely accepted in the past fifteen years. Hunter, writing in 1793, stated th.at : " Many wounds ought to be allowed to scab in which this process is now prevented, and this arises, I believe, from the conceit of surgeons who think themselves possessed of powers superior to nature and therefore have introduced the practice of making sores of all wounds." Wallace (1949) suggested that burnt surfaces be exposed on the assumption that a dry cool slough would no~t offer a favourable medium for the growth of pathogenic organisms. His experiments in Edinburgh were confirmed by other centres and so exposure is an accepted form of treatment to-day. Some workers are still doubtful of the value of exposure. Sevitt (1957), Lowbury et al. (1954) considered that pyocyaneus can be cultured from the deep surface of the slough and both streptococcal and staphylococcal infections were more common than when closed dressings and topical antibiotics were used. On the other hand Clarkson and Evans (1954) found that the exposure technique reduced the average in-patient stay at the Basingstoke Burns Centre (now at Roehampton) from 43 to 32 days. Artz and Gaston (1960) report very satisfactory results, using exposure for the past ten years. They maintain that the infection is effectively limited and a deep partial skin burn will not be converted to a full thickness skin loss, as sometimes occurs when closed dressings are employed. The technique described is that which is currently employed at the Burns Centre of Queen Mary's Hospital, Roehampton. When shock permits, usually within an hour or two of admission, the burnt surface is cleansed with ]% Savlon; all blisters and necrotic materials are excised. The patient is nursed on a special nylon frame which is cushioned by a h,alf inch thick layer of sterile polyurethene foam. The latter is sprayed with silicone to limit adhesion to the burnt surface. A temperature of approximately 75 ~ F. is maintained in the room and a flow of air through the polyurethene and around the burnt surfaces is assured by means of an electric fan heater placed on the floor under the frame. Burnt limbs are elevated on Cramer wire splints padded with polyurethene foam; this limits the amount of oedema. After sw.ab testing the burnt surfaces and the nose and throat, the patient is prescribed systemic penicillin for five days and topical penicillin powder until the slough is dry. *Read at a Meeting of the Section of Surgery, Royal Academy of Medicine in Ireland,