Reduction Of Dead Space Research Articles

Asymmetrical high-flow nasal cannula performs similarly to standard interface in patients with acute hypoxemic post-extubation respiratory failure: a pilot study

BackgroundStandard high-flow nasal cannula (HFNC) is a respiratory support device widely used to manage post-extubation hypoxemic acute respiratory failure (hARF) due to greater comfort, oxygenation, alveolar recruitment, humidification, and reduction of dead space, as compared to conventional oxygen therapy. On the contrary, the effects of the new asymmetrical HFNC interface (Optiflow® Duet system (Fisher & Paykel, Healthcare, Auckland, New Zealand) is still under discussion. Our aim is investigating whether the use of asymmetrical HFNC interface presents any relevant difference, compared with the standard configuration, on lung aeration (as assessed by end-expiratory lung impedance (EELI) measured by electrical impedance tomography (EIT)), diaphragm ultrasound thickening fraction (TFdi) and excursion (DE), ventilatory efficiency (estimated by corrected minute ventilation (MV)), gas exchange, dyspnea, and comfort.MethodsPilot physiological crossover randomized controlled study enrolling 20 adults admitted to the Intensive Care unit, invasively ventilated for at least 24 h, and developing post-extubation hARF, i.e., PaO2/set FiO2 < 300 mmHg during Venturi mask (VM) within 120 min after extubation. Each HFNC configuration was applied in a randomized 60 min sequence at a flow rate of 60 L/min.ResultsGlobal EELI, TFdi, DE, ventilatory efficiency, gas exchange and dyspnea were not significantly different, while comfort was greater during asymmetrical HFNC support, as compared to standard interface (10 [7–10] and 8 [7–9], p-value 0.044).ConclusionsIn post-extubation hARF, the use of the asymmetrical HFNC, as compared to standard HFNC interface, slightly improved patient comfort without affecting lung aeration, diaphragm activity, ventilatory efficiency, dyspnea and gas exchange.Clinical trial numberClinicalTrial.gov. Registration number: NCT05838326 (01/05/2023).New & noteworthyThe asymmetrical high-flow nasal cannula oxygen therapy (Optiflow® Duet system (Fisher & Paykel, Healthcare, Auckland, New Zealand) provides greater comfort as compared to standard interface; while their performance in term of lung aeration, diaphragm activity, ventilatory efficiency, dyspnea, and gas exchange is similar.

Low-flow ECCO2R conjoined with renal replacement therapy platform to manage pulmonary vascular dysfunction with refractory hypercapnia in ARDS

BackgroundHypercapnia worsens lung vascular dysfunction during acute respiratory distress syndrome (ARDS). We tested whether an extracorporeal carbon dioxide removal (ECCO2R) device based on a renal replacement therapy platform (Prismalung®) may reduce PaCO2 and alleviate lung vascular dysfunction in ARDS patients with refractory hypercapnia. MethodsWe planned to prospectively include 20 patients with moderate-to-severe ARDS, pulmonary vascular dysfunction on echocardiography, and PaCO2 ≥ 48 mmHg despite instrumental dead space reduction and the increase in respiratory rate. Hemodynamics, echocardiography, respiratory mechanics, and arterial blood gases were recorded at 2 (H2), 6 (H6) and 24 (H24) hours as ECCO2R treatment was continued for at least 24 h. ResultsOnly eight patients were included, and the study was stopped due to worldwide shortage of ECCO2R membranes and the pandemic. Only one patient fulfilled the primary endpoint criterion (decrease in PaCO2 of more than 20 %) at H2, but this objective was achieved in half of patients (n = 4) at H6. The percentage of patients with a PaCO2 value < 48 mmHg increased with time, from 0/8 (0 %) at H0, to 3/8 (37.5 %) at H2 and 4/8 (50 %) at H6 (p = 0.04). There was no major change in hemodynamic and echocardiographic variables with ECCO2R, except for a significant decrease in heart rate. ECCO2R was prematurely discontinued before H24 in five (62.5 %) patients, due to membrane clotting in all cases. ConclusionsThis pilot study testing showed a narrow efficacy and high rate of membrane thrombosis with the first version of the system. Improved versions should be tested in future trials. Trial registrationRegistered at clinicaltrials.gov, identifier: NCT03303807, Registered: October 6, 2017, https://clinicaltrials.gov/ct2/show/NCT03303807.

Drain-free donor site in Deep Inferior Epigastric Perforator free flap: A single-surgeon experience

Donor-site seroma and wound dehiscence in Deep Inferior Epigastric Perforator (DIEP) free flaps can be problematic. The value of donor-site drains is debated, with alternative closure techniques demonstrating good outcomes. However, no literature exists on patient outcomes in which no drain or dead space reduction technique is used. The senior author of this paper has opted for a drain-free, simple layered closure without adjuncts since 2016. We evaluate the outcomes of this technique against the literature. A single-center, single-surgeon, prospective study of all DIEP flap breast reconstruction between January 2016 and March 2020, whereby the donor site was closed without drains or alternative dead space reduction measures. One hundred and thirty-eight patients with a mean age of 50.72±9.16 (range 26-73) underwent DIEP breast reconstruction (78% unilateral (n=107), 22% bilateral (n=31). The incidence of drain-free specific donor-site complications was 8.7%, with wound breakdown being the most common (9/138, 6.5%). However, only one patient required secondary closure. The average length of hospital stay was 4.2±1 days (range 2-9). Abdominal drains may serve as a psychological barrier for patients in expediting discharge and can be painful and cumbersome. This translates into significant cost implications. Evidence suggests that superior outcomes are achieved when dead space-reducing adjuncts rather than drains are used. However, our data suggest that DIEP donor sites can also be safely closed without these adjuncts, which may unnecessarily lengthen procedure time, consume more resources, and increase localized foreign body tissue reactions, without good indication.

Exercise Tolerance in Patients With Idiopathic Pulmonary Fibrosis, Effect of Supplemental Oxy-Gen.

Exercise tolerance in patients with idiopathic pulmonary fibrosis IPF is mainly limited by mechanical constrain of ventilation and high physiologic dead space. Oxygen enriched gas inhalation seems to increase ventilatory efficiency by reduction of dead space to tidal volume ratio (VD/VT) which probably mirrors improved pulmonary capillary flow and leads to longer physical tolerance at lower level of minute ventilation. The effect is noticeable at FIO2 that can be delivered in rehabilitation purposes or daily living activities.

Early prolonged prone position in noninvasively ventilated patients with SARS-CoV-2-related moderate-to-severe hypoxemic respiratory failure: clinical outcomes and mechanisms for treatment response in the PRO-NIV study

BackgroundWhether prone position (PP) improves clinical outcomes in COVID-19 pneumonia treated with noninvasive ventilation (NIV) is unknown. We evaluated the effect of early PP on 28-day NIV failure, intubation and death in noninvasively ventilated patients with moderate-to-severe acute hypoxemic respiratory failure due to COVID-19 pneumonia and explored physiological mechanisms underlying treatment response.MethodsIn this controlled non-randomized trial, 81 consecutive prospectively enrolled patients with COVID-19 pneumonia and moderate-to-severe (paO2/FiO2 ratio < 200) acute hypoxemic respiratory failure treated with early PP + NIV during Dec 2020–May 2021were compared with 162 consecutive patients with COVID-19 pneumonia matched for age, mortality risk, severity of illness and paO2/FiO2 ratio at admission, treated with conventional (supine) NIV during Apr 2020–Dec 2020 at HUMANITAS Gradenigo Subintensive Care Unit, after propensity score adjustment for multiple baseline and treatment-related variables to limit confounding. Lung ultrasonography (LUS) was performed at baseline and at day 5. Ventilatory parameters, physiological dead space indices (DSIs) and circulating inflammatory and procoagulative biomarkers were monitored during the initial 7 days.ResultsIn the intention-to-treat analysis. NIV failure occurred in 14 (17%) of PP patients versus 70 (43%) of controls [HR = 0.32, 95% CI 0.21–0.50; p < 0.0001]; intubation in 8 (11%) of PP patients versus 44 (30%) of controls [HR = 0.31, 95% CI 0.18–0.55; p = 0.0012], death in 10 (12%) of PP patients versus 59 (36%) of controls [HR = 0.27, 95% CI 0.17–0.44; p < 0.0001]. The effect remained significant within different categories of severity of hypoxemia (paO2/FiO2 < 100 or paO2/FiO2 100–199 at admission). Adverse events were rare and evenly distributed. Compared with controls, PP therapy was associated with improved oxygenation and DSIs, reduced global LUS severity indices largely through enhanced reaeration of dorso-lateral lung regions, and an earlier decline in inflammatory markers and D-dimer. In multivariate analysis, day 1 CO2 response outperformed O2 response as a predictor of LUS changes, NIV failure, intubation and death.ConclusionEarly prolonged PP is safe and is associated with lower NIV failure, intubation and death rates in noninvasively ventilated patients with COVID-19-related moderate-to-severe hypoxemic respiratory failure. Early dead space reduction and reaeration of dorso-lateral lung regions predicted clinical outcomes in our study population.Clinical trial registrationISRCTN23016116. Retrospectively registered on May 1, 2021.

Advanced cuff pressure control ventilation (ACPCV); a bench study of a new concept of mechanical ventilation

The concept of advanced cuff pressure control ventilation (ACPCV) is that the endotracheal tube (ETT) cuff volume could be controlled and allowed to exhale the gas through the vocal cords. The potential advantages of ACPCV are reduction of dead space, reduction of expiratory airway resistance, and preservation of vocal cord function. We developed the ACPCV system and investigated its performance in bench studies. The ETT cuff volume was regulated via four steps, depending on airway pressure and tracheal pressure. Two ventilatory settings were examined under several rates of spontaneous breathing efforts. Imposed expiratory resistance (RE ), imposed expiratory work of breathing (WOB), and auto-PEEP of ACPCV were compared with continuous mandatory ventilation (CMV). RE of ACPCV (2.6 ± 0.5 cm H2O/l/s) was significantly lower than that of CMV (11.6 ± 1.6 cm H2O/l/s) (p < 0.001). Expiratory WOB of ACPCV (0.25 ± 0.02 J/l) was significantly lower than that of CMV (0.54 ± 0.10 J/l) (p < 0.001). Auto-PEEP of ACPCV (−0.6 ± 0.2 cm H2O) was significantly lower than that of CMV (1.1 ± 0.7 cm H2O) (p < 0.001). ACPCV can significantly reduce RE and expiratory WOB by controlling the ETT cuff volume in synchronisation with mechanical ventilation.

In Response.

We thank Dr A. K. Jha1 for his valuable comments regarding our article.2 Although there is a correlation between the relative perfusion to the operative lung as assessed by lung scans and the partial pressure of oxygen in arterial blood (Pao2), it is unclear whether this variable is clinically relevant for patients undergoing thoracic surgery.3 Because not all the patients enrolled in our trial underwent lung perfusion scans, we did not perform a between-group comparison. We also did not measure Pao2 levels by arterial blood gas analysis during 2-lung ventilation (TLV). Because the Pao2 level during 1-lung ventilation (OLV) strongly and positively correlates with Pao2 during TLV, we were able to predict hypoxemia during OLV for patients in both groups that presented with an average room air saturation of 93% before general anesthesia. Nonetheless, we acknowledge that the TLV parameters and preoperative perfusion scans may give more insight on the impact of OLV, peak inspiratory pressure (PIP) and Pao2/fractional inspiration of oxygen (Fio2) (P/F) ratio. Hypoxic pulmonary vasoconstriction (HPV) during OLV mitigates the shunt fraction. HPV is blunted by sevoflurane and suppressed by the pathologic effects of chronic obstructive pulmonary disease (COPD). Although we did measure sevoflurane concentrations, we administered balanced anesthesia that included a remifentanil infusion. Thus, the actual concentration of sevoflurane was probably less than 1 minimum alveolar concentration (MAC), a concentration thought to have limited impact on HPV.4 Also, the treatment of OLV-induced increase in pulmonary hypertension may have been beneficial, as Dr A. K. Jha1 commented in the letter. Unfortunately, as we mentioned in the limitation section, we can only speculate there was an OLV-induced rise in pulmonary artery pressure because it was not possible to obtain accurate measurements of pulmonary arterial pressure in our clinical practice. We agree with the view that iloprost-induced pulmonary arteriolar vasodilation in the ventilated lung resulted in blood diversion from nonventilated lung to the ventilated lung with physiological dead space reduction and P/F ratio augmentation. Indeed, as our study results indicate, inhaled iloprost improves oxygenation and dead space ventilation during OLV in COPD patients with poor lung oxygenation. Considering that atelectasis in the operated lung persists in the postoperative period,5 it can be deduced that the difference in P/F ratio in the postanesthetic care unit in both groups may be due to the residual intrapulmonary shunt fraction and the residual effects of iloprost inhalation, which ameliorates the ventilation/perfusion matching. In this regard, we speculate that the beneficial effects of iloprost during OLV may persist even after TLV or spontaneous ventilation is restored, but this needs to be clarified. We think that the comments provided by Dr A. K. Jha1 are valuable and should be considered when planning further studies. Namo Kim, MD, PhDDepartment of Anesthesiology and Pain MedicineAnesthesia and Pain Research InstituteYonsei University College of MedicineSeoul, Republic of Korea Su Hyun Lee, MDDepartment of Anesthesiology and Pain MedicineYonsei Sarang HospitalSeoul, Republic of Korea Young Jun Oh, MD, PhDDepartment of Anesthesiology and Pain MedicineAnesthesia and Pain Research InstituteYonsei University College of MedicineSeoul, Republic of Korea[email protected]

Tidal Volume Lowering by Instrumental Dead Space Reduction in Brain-Injured ARDS Patients: Effects on Respiratory Mechanics, Gas Exchange, and Cerebral Hemodynamics.

BackgroundLimiting tidal volume (VT), plateau pressure, and driving pressure is essential during the acute respiratory distress syndrome (ARDS), but may be challenging when brain injury coexists due to the risk of hypercapnia. Because lowering dead space enhances CO2 clearance, we conducted a study to determine whether and to what extent replacing heat and moisture exchangers (HME) with heated humidifiers (HH) facilitate safe VT lowering in brain-injured patients with ARDS.MethodsBrain-injured patients (head trauma or spontaneous cerebral hemorrhage with Glasgow Coma Scale at admission < 9) with mild and moderate ARDS received three ventilatory strategies in a sequential order during continuous paralysis: (1) HME with VT to obtain a PaCO2 within 30–35 mmHg (HME1); (2) HH with VT titrated to obtain the same PaCO2 (HH); and (3) HME1 settings resumed (HME2). Arterial blood gases, static and quasi-static respiratory mechanics, alveolar recruitment by multiple pressure–volume curves, intracranial pressure, cerebral perfusion pressure, mean arterial pressure, and mean flow velocity in the middle cerebral artery by transcranial Doppler were recorded. Dead space was measured and partitioned by volumetric capnography.ResultsEighteen brain-injured patients were studied: 7 (39%) had mild and 11 (61%) had moderate ARDS. At inclusion, median [interquartile range] PaO2/FiO2 was 173 [146–213] and median PEEP was 8 cmH2O [5–9]. HH allowed to reduce VT by 120 ml [95% CI: 98–144], VT/kg predicted body weight by 1.8 ml/kg [95% CI: 1.5–2.1], plateau pressure and driving pressure by 3.7 cmH2O [2.9–4.3], without affecting PaCO2, alveolar recruitment, and oxygenation. This was permitted by lower airway (− 84 ml [95% CI: − 79 to − 89]) and total dead space (− 86 ml [95% CI: − 73 to − 98]). Sixteen patients (89%) showed driving pressure equal or lower than 14 cmH2O while on HH, as compared to 7 (39%) and 8 (44%) during HME1 and HME2 (p < 0.001). No changes in mean arterial pressure, cerebral perfusion pressure, intracranial pressure, and middle cerebral artery mean flow velocity were documented during HH.ConclusionThe dead space reduction provided by HH allows to safely reduce VT without modifying PaCO2 nor cerebral perfusion. This permits to provide a wider proportion of brain-injured ARDS patients with less injurious ventilation.

Use of Calender Extract Cream in Equine Lacerate Wound

Background: Wounds and lacerations are constant in the clinical routine of horses. The treatment of wounds by the second intention is the most common in the equine clinic; it consists in addition to surgical debridement, the use of allopathic or phytotherapeutic healing. In this context, several phytotherapics used in folk medicine have been used with promising results in the equine species, especially marigold (Calendula officinalis L.), recognized by the German scientific committee as antiseptic and healing. The objective of this study was to evaluate the efficacy of the nonionic cream of Calendula officinalis at 2% in an extensive lacerating wound in an equine.Case: A 6-month-old female Quarter Horse, weighing 160 kg, a lacerating wound in the pectoral region of unknown traumatic origin, was treated in the large animal sector of the Veterinary Hospital of Universidade Paranaense (UNIPAR). Clinical examination revealed an exudative wound in the pectoral region, complicated by the presence of environmental organic matter and myiasis, involving transverse pectoral and descending pectoral muscles, with a large tissue separation and exposure of part of the first sternum. After an initial evaluation, a trichotomy was performed around the wound, removal of myiasis and sanitization of the wound with water and PVP-I, which was filled with sterile dressings and covered with a dressing using a tubular mesh. Antibiotic therapy was instituted, along with anti-inflammatory medication and antitetanic serum (5,000 IU). Due to the need for surgical debridement, after previous fasting and general anesthesia followed by site antisepsis, surgical debridement was performed, followed by reduction of dead space with application of standard "Wolf" sutures, for re-approximation of the wound edges was applied suture in Wolf pattern captonated with segments of equipment. In the post-surgical period, topical treatment with nitrofurazone ointment and crystal sugar was instituted. However, after five days of the surgical procedure, there was dehiscence of the wound, at which time another intervention was chosen. After sedation remaining in standard anatomical position, sutures of the same pattern and wire were applied, but captonated with polyester buds and wound dressing was instituted, followed by the application of nonionic cream of marigold (C. officinalis) extract, in the concentration of 2%, twice a day until complete healing of the wound.Discussion: The use of nonionic marigold cream (C. officinalis) 2% showed a significant efficacy, in the case reported, corroborating with literature data that marigold presented an advantage in the inflammatory phase of the healing process, when compared to the other two substances, favored epithelization and demonstrated bactericidal action. This activity is reported to the substances present in C. officinalis, especially the flavonoids, which are phenolic compounds derived from the secondary metabolism of plants. In addition to phenolic compounds such as triterpenes, faradiol esters and taraxasterol are considered responsible for antioxidant, anti-inflammatory, antimicrobial and angiogenic activities, actions that contribute directly or indirectly to the healing process. The present report contributes positively to the use of alternative treatments in wounds as the phytotherapeutic in question, since it proved feasible, besides avoiding the use of allopathic ones with higher associated costs and environmental impact in its production and use, as well as the emergence of bacterial resistance.

Factors affecting seroma formation after mastectomy among West African patients: a single center experience in North West Nigeria

Introduction: seroma is a collection of serous fluid in the dead space of skin flaps or axilla following mastectomy. There have been various methods for preventing seroma, such as prolonged suction drainage, shoulder immobilization, reduction of dead space, among others. We present our experience on factors affecting seroma formation after mastectomy among West African patients.

MEDICAL MANAGEMENT OF BILATERAL FLAIL CHEST CAUSED BY PROLONGED CPR

SESSION TITLE: Wednesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Flail chest is a life-threatening condition caused by blunt trauma to the chest resulting in fractures of three or more consecutive ribs in two or more places with paradoxical motion. We present a rare case of bilateral flail chest secondary to trauma from manual CPR that recovered without surgical intervention. CASE PRESENTATION: A 65-year-old man presented to our hospital with MI, complicated by VF and cardiac arrest. He was emergently intubated and after 42 minutes of manual CPR he had ROSC. Several attempts at weaning the AC/PC were unsuccessful due to agitation, desaturation, tachypnea. CT chest showed acute fractures of lateral right fourth, anterior right fifth, anterior right sixth, lateral left fourth, anterior left fifth, and anterior left sixth ribs in addition to inward movement of the chest. There was a conservative strategy due to the high risk of bleeding on Ticagrelor and persistent fever (pan-sensitive MSSA on respiratory culture). Pain was managed with Precedex, Hydromorphone, and Midazolam drips then transitioned to Propofol and Gabapentin. He was then started on Oxycodone and Seroquel. On hospital day 25 the patient was weaned off Propofol, was A&O, and transitioned to tracheostomy collar/Fentanyl Patch. DISCUSSION: It is believed that the mortality from flail chest is secondary to complications rather than the flail chest itself, although visceral chest wall injuries such as pulmonary contusions and hemothorax are common. Nevertheless, without proper sedation/pain management (successive use of analgesics/sedatives with different pharmacological properties), and cautious attention to possible complications (VAP, mucous plugging, pulmonary contusions), this patient may have suffered from increased M&M.Pain control was difficult in an awake state; hence he was placed on Propofol for almost the entirety of his stay. At one point he was receiving high dose Hydromorphone, Oxycodone, Precedex, and Propofol. While there may be significant morbidity and additive effect of multiple opioids/sedatives, it was only with meticulous and slow discontinuation of these sedatives that the patient was able to successfully wake up with good pain control and relatively minimal delirium. While epidural/paravertebral blocks were considered, the patient’s DAPT precluded the their use. Secondly, because of the patient’s unusual distribution of fracture, regional anesthesia, would have also been difficult and short-lived. Early tracheostomy was warranted in this situation for comfort, pulmonary toilet, reduction of dead space, and sedative needs. CONCLUSIONS: Rib fractures and flail chest can produce significant morbidity for the elderly. Pain control, pulmonary toilet, and volume expansion measures are critical to reducing complications and further M&M. While surgical fixation continues to be controversial, medical management of even the most severe cases of flail chest can be successful. Reference #1: Phillips B, Murray E, Holzmer S . Bilateral Flail Chest: A review. Journal of Trauma and Orthopaedic Surgery.April - June 2017;12(2):2-7. Reference #2: Dehghan N, de Mestral C, McKee MD, et al. Flail chest injuries: a review of outcomes and treatment practices from the National Trauma Data Bank. J Trauma Acute Care Surg 2014; 76:462. Reference #3: R.S. Hoke, D. Chamberlain. Skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation, 63 (2004), pp. 327-338. DISCLOSURES: No relevant relationships by Hany Abdallah, source=Web Response no disclosure on file for Leila Hosseinian

Aligning Lung Function Equipment and Reference Values in Adults

Background: When introducing new equipment or reference equations into the lung function laboratory, systematic z-score deviations could arise due to local differences in population or equipment. Objective: To propose a workable method for aligning reference equations with lung function equipment. Method: Using two cases of equipment transition in our laboratory as a test case, we first performed lung function testing after the transition, on a control group of 40 normal young adults (20 male/20 female; 20–30 years old). For those indices with an average z-score in excess of ±0.5, adapted reference values were obtained by an offset or scaling factor on the M coefficient with the so-called lambda-mu-sigma (LMS) method recommended by the Global Lung Function Initiative, and the z-scores were computed again. Results: Following a transition involving instrumental dead space reduction, the lung clearance index was predictably reduced, resulting in a mean (±SD) z-score of –1.9 (±1.1) in the control group; by adapting the reference values with an offset on M, the z-score became –0.1 (±1.1). Applying the same method to a transition of standard lung function equipment, the z-scores became centered around zero in the control group, but also became properly aligned in a test group of 81 other subjects spanning a wider age range (20–80 years). Conclusions: We proposed and verified a method for aligning local equipment with reference values obtained elsewhere, or following a local change in equipment. The key is to measure a relatively small young adult group, identifying those lung function indices that need adaptation based on z-scores, in order to then obtain laboratory-specific reference values that can be applied over the entire age range.

Primary soft tissue management in open fracture

Debridement of soft tissue and bone in an open fracture situation to minimize infection risk and achieve primary skin closure, or to provide conditions for early soft tissue coverage. Indications are Gustilo-Anderson gradeI-III A-C open fractures. Contraindications are injuries requiring amputation, burns, and life-threatening injuries which make appropriate treatment temporarily impossible. Removal of gross contamination and macroscopic contaminants; debridement of the wound; complete resection of contaminated and dirty tissue; sparse step-by-step resection of contaminated or non-vital wound and bone margins until vital, bleeding tissue begins; low-pressure irrigation with isotonic irrigation fluid; diagnostic biopsies for microbiological testing; reduction of dead space by interpositioning of muscle or cement spacers loaded with local antibiotics; primary wound closure if tension-free closure possible; otherwise, if resources and knowhow permit and satisfactory clean debridement was achieved, local flap; if flap impossible, debridement not satisfactory, secondary tissue necrosis likely, potential remaining contamination or contamination with fecal matter, then vacuum-assisted closure therapy. Wound inspection on the second postoperative day, generous indication for second-look surgery after 36-48 h, wound inspection on the second postoperative day, wound inspection every other day, primary antibiotic prophylaxis with afirst- or second-generation cephalosporin (e. g., cefuroxime), and adaptation of antibiotic therapy according to susceptibility screening. Infection rates of 2-4.7% are reported for immediate primary wound closure in Gustilo-Anderson gradeI, II, and III A open fractures. For Gustilo-Anderson gradeIII B, good wound healing, bony consolidation, and no need for secondary surgery was reported in 86.7% when primary wound closure was achieved.

0769 Polysomnographic Analysis Of Post-stimulation Titration In Children With Down Syndrome And Hypoglossal Nerve Implant

Hypoglossal nerve stimulator implantation (HGN) can significantly improve obstructive sleep apnea and neurocognitive development in children with Down syndrome (DS). Effective stimulation requires postoperative titration with serial polysomnography and outcomes are measured based on reduction of apnea- hypopnea index (AHI). Given the novelty of the procedure, objective guidelines for post- stimulation titration are still lacking. Polysomnographic analysis of adverse events during post- stimulation polysomnography in adolescent DS patients with HGN. The American Academy of Sleep Medicine (AASM) pediatric scoring system was used to quantify respiratory events and evaluate treatment success. We examined four complications seen during titration polysomnography: Adverse events included 1) titration induced central apneas likely due to dead space reduction that resolved during continued stimulation, 2) insufficient response to increasing voltage stimulation with residual apnea burden requiring repeated recalibration, 3) aberrant electric cardiac stimulation at higher voltage stimulation; and 4) neuropathic pain with deactivated device. Polysomnography is invaluable for post-stimulation titration to reduction of respiratory events and oxygen desaturations and evaluate treatment Stringent criteria should be used to evaluate treatment success of HGN on post-stimulation polysomnography. Our data suggest that inefficient titration can leave patients with a central or obstructive apnea burden and stimulation induced side effects. Titration parameters need to be better defined and since effectiveness of titration is based on AHI, pediatric (rather than adult) scoring criteria should be considered for adolescents with DS. none.

English

English

Efficacy of Target Drug Delivery and Dead Space Reduction Using Antibiotic-loaded Bone Cement for the Treatment of Complex Spinal Infection.

A retrospective study. We have treated complex cases of surgical site infection (SSI) successfully using antibiotic-loaded bone cement to avoid the need for implant removal. In the present study, we describe a new treatment option for SSI. Although there are several treatment options for SSI after spinal surgery involving instrumentation, several types of problems may arise and are difficult to cure. Eleven patients with SSI after undergoing spinal surgery involving instrumentation were studied. All had been refractory to conventional treatments, including intravenous antibiotic administration and conventional debridement and irrigation. Antibiotic-loaded bone cement was placed on and around the instrumentation to cover them and to occupy the surrounding dead space. Two general types of antibiotics were loaded into the polymethylmethacrylate bone cement. The recipes for the mixture were changed depending on the bacterial cultures. Sensitive antibiotics were administered generally for 2-6 weeks until the C-reactive protein level was normalized. All patients were treated successfully using antibiotic-loaded bone cement. Only 1 patient needed a repeat of this procedure to treat an infection. Antibiotic-loaded bone cement was placed in situ in all patients during the follow-up period and there were no significant adverse events. Antibiotic-loaded bone cement treatment reduces the dead space and achieves the targeted drug delivery simultaneously. Treatment using antibiotic-loaded bone cement is an effective treatment option for complex spinal SSI.

Implantation of Thickened Artificial Bone for Reduction of Dead Space and Prevention of Infection Between Implant and Dura in Secondary Reconstruction of the Skull.

For the treatment of skull defect compensation after neurosurgery, a customized artificial bone is often employed owing to its toughness and the relative ease of producing cosmetically good result. However, implants are vulnerable to infection and removal of implant is sometimes necessary. Several other treatment options such as autologous bone graft or free flap are likely to be considered for the secondary reconstruction to avoid reinfection; however, reimplantation of artificial bone is beneficial for the patients, being not concerned with donor site morbidity. The authors consider one of risk factors of infection of artificial bone as dead space between the implant and dura. To attain reduction of the dead space, we have employed thickened artificial bone.Between 2010 and 2014, 6 patients underwent implantation of thickened artificial bone for the secondary reconstruction.First, the infected artificial material was removed with proper debridement. More than 3 months after the closure of the infected wound, tissue expander was inserted beneath the surrounding scalp to ensure the coverage of subsequently implanted artificial bone without skin tension. The thickened artificial bone was designed from the computed tomography findings so as not to leave any dead space between the implant and dura. After optimal expansion of the scalp, the artificial bone was implanted.Postoperative courses were uneventful and the appearance of the cranial vault was satisfactory in all patients.The authors consider the use of the thickened artificial bone is easier and more suitable for patients having a skull defect, particularly in secondary reconstruction.

Nasal high flow reduces dead space.

Recent studies show that nasal high flow (NHF) therapy can support ventilation in patients with acute or chronic respiratory disorders. Clearance of dead space has been suggested as being the key mechanism of respiratory support with NHF therapy. The hypothesis of this study was that NHF in a dose-dependent manner can clear dead space of the upper airways from expired air and decrease rebreathing. The randomized crossover study involved 10 volunteers using scintigraphy with 81mKrypton (81mKr) gas during a breath-holding maneuver with closed mouth and in 3 nasally breathing tracheotomized patients by volumetric capnography and oximetry through sampling CO2 and O2 in the trachea and measuring the inspired volume with inductance plethysmography following NHF rates of 15, 30, and 45 l/min. The scintigraphy revealed a decrease in 81mKr gas clearance half-time with an increase of NHF in the nasal cavities [Pearson’s correlation coefficient cc = −0.55, P < 0.01], the pharynx (cc = −0.41, P < 0.01), and the trachea (cc = −0.51, P < 0.01). Clearance rates in nasal cavities derived from time constants and MRI-measured volumes were 40.6 ± 12.3 (SD), 52.5 ± 17.7, and 72.9 ± 21.3 ml/s during NHF (15, 30, and 45 l/min, respectively). Measurement of inspired gases in the trachea showed an NHF-dependent decrease of inspired CO2 that correlated with an increase of inspired O2 (cc = −0.77, P < 0.05). NHF clears the upper airways of expired air, which reduces dead space by a decrease of rebreathing making ventilation more efficient. The dead space clearance is flow and time dependent, and it may extend below the soft palate.NEW & NOTEWORTHY Clearance of expired air in upper airways by nasal high flow (NHF) can be extended below the soft palate and de facto causes a reduction of dead space. Using scintigraphy, the authors found a relationship between NHF, time, and clearance. Direct measurement of CO2 and O2 in the trachea confirmed a reduction of rebreathing, providing the actual data on inspired gases, and this can be used for the assessment of other forms of respiratory support.

Novel Method of Surgical Incision Management in Patients Undergoing Colorectal Surgery

We previously demonstrated that subcutaneous drain is effective for preventing incisional surgical site infection (SSI) in patients with thick subcutaneous fat in colorectal surgery. We have recently attempted a novel closure technique in colorectal surgery for the prevention of incisional SSI. In the current study, we described this novel method for prevention of incisional SSI and share our assessment of efficiency of this incision management in patients undergoing colorectal surgery. The procedure “wound dressing with temporary negative pressure” using Opsite Post-Op Visible and an Atom Multipurpose Tube, is a simple and easy method. Immediately after incisions were closed, Opsite Post-Op Visible dressing was applied over the incision site with an Atom Multipurpose catheter, and negative pressure was applied through the catheter. We analyzed the cases of 203 patients who underwent colorectal resection. In 60 cases, we performed this negative pressure system for prevention of SSI. We reviewed the clinical features of these cases treated by this novel method and found that the incisional SSI rate in patients who underwent colorectal resection was significantly reduced following the use of the new method. There were no complications in any of the cases due to DNP. This dressing with negative pressure (DNP) may lead to wound drainage and a reduction of dead space in a subcutaneous wound area. These findings indicate that the use of DNP is safe, easy, and effective for preventing incisional SSI in patients undergoing colorectal surgery.

Reduction of Endotracheal Tube Connector Dead Space Improves Ventilation: A Bench Test on a Model Lung Simulating an Extremely Low Birth Weight Neonate.

The reduction of instrumental dead space is a recognized approach to preventing ventilation-induced lung injury in premature infants. However, there are no published data regarding the effectiveness of instrumental dead-space reduction in endotracheal tube (ETT) connectors. We tested the impact of the Y-piece/ETT connector pairs with reduced instrumental dead space on CO2 elimination in a model of the premature neonate lung. The standard ETT connector was compared with a low-dead-space ETT connector and with a standard connector equipped with an insert. We compared the setups by measuring the CO2 elimination rate in an artificial lung ventilated via the connectors. The lung was connected to a ventilator via a standard circuit, a 2.5-mm ETT, and one of the connectors under investigation. The ventilator was run in volume-controlled continuous mandatory ventilation mode. The low-dead-space ETT connector/Y-piece and insert-equipped standard connector/Y-piece pairs had instrumental dead space reduced by 36 and 67%, respectively. With set tidal volumes (VT) of 2.5, 5, and 10 mL, in comparison with the standard ETT connector, the low-dead-space connector reduced CO2 elimination time by 4.5% (P < .05), 4.4% (P < .01), and 7.1% (not significant), respectively. The insert-equipped standard connector reduced CO2 elimination time by 13.5, 25.1, and 16.1% (all P < .01). The low-dead-space connector increased inspiratory resistance by 17.8% (P < .01), 9.6% (P < .05), and 5.0% (not significant); the insert-equipped standard connector increased inspiratory resistance by 9.1, 8.4, and 5.9% (all not significant). The low-dead-space connector decreased expiratory resistance by 6.8% (P < .01) and 1.8% (not significant) and increased it by 1.4% (not significant); the insert-equipped standard connector decreased expiratory resistance by 1.5 and 1% and increased it by 1% (all not significant). The low-dead-space connector increased work of breathing by 4.7% (P < .01), 3.8% (P < .01), and 2.5% (not significant); the insert-equipped standard connector increased it by 0.8% (not significant), 2.5% (P < .01), and 2.8% (P < .01). Both methods of instrumental dead-space reduction led to improvements in artificial lung ventilation. Negative effects on resistance and work of breathing appeared minimal. Further testing in vivo should be performed to confirm the lung model results and, if successful, translated into clinical practice.