Paykel Healthcare Research Articles

Nasal High Flow in Children with Acute Hypoxemic Respiratory Failure. A Paediatric Acute Respiratory Intervention Study (Paris)

Background: High-flow oxygen-therapy is increasingly used in children with acute hypoxic respiratory failure (AHRF), despite limited high-quality evidence of efficacy outside intensive care units. Methods: An open labelled RCT feasibility design was used in emergency departments and general wards of two tertiary children's hospitals. Over a period of 1-year, children aged 0-16 years with AHRF were randomised (1:1) to either high-flow or standard-oxygen. Children on the standard-oxygen could receive rescue high-flow in the general wards if their conditions met treatment failure criteria. The primary efficiency-endpoints were feasibility, recruitment rates and safety followed by the efficacy-endpoints measuring the proportion escalation of care. We measured the duration of hospital stay, duration of oxygen therapy and rates of ICU admission. Findings: Of 563 randomised, 283 received high-flow and 280 standard-oxygen with no adverse events. The proportion of children receiving escalation of care was 11.7% (32/283 children) on the high-flow and 18.1% (50/280 infants) on standard-oxygen (risk difference -6.4 percentage points; 95% CI -12.4%, -0.5%; p=0.04). In children with obstructive airway disease 9.7% on high-flow and 17.4% on standard-oxygen required escalation (risk difference -7.7% percentage points; 95% CI -14.3%, -1.1%; p=0.03), whereas in children with non-obstructive disease no difference was observed. No difference in length of hospital stay was observed. 40% of children who failed standard-oxygen responded to rescue high-flow. Interpretation: High-flow outside ICU appears to be safe in children with AHRF and the required proportion of escalation was lower compared to standard-oxygen. The trial design can be applied in a future large RCT. Trial Registration: The study protocol was registered with the Australian and New Zealand Clinical Trials Registry. (ACTRN12615001305516). Funding Statement: The study was supported by a grant provided by Thrasher Research Fund and a project grant provided by the National Health and Medical Research Council. The high-flow equipment and consumables for both trial sites were donated by Fisher & Paykel Healthcare, which had no involvement in the design and conduct of the trial, the analysis of the data, or in the preparation of the manuscript. Declaration of Interests: DF and AS report financial support for travel and accommodation provided by Fisher&Paykel Healthcare, Auckland, New Zealand Ethics Approval Statement: The study was approved by Children’s Health Queensland Human Research Ethics Committee (HREC/15/QRCH/159) and the authors used a consent to continue process.

Nasal High-Flow Preoxygenation for Endotracheal Intubation in the Critically Ill Patient: A Randomized Clinical Trial

Background: Although performed daily, intubation in intensive care units (ICU) remains a critical procedure with life-threatening adverse events. High-flow therapy by nasal cannulae (HFNC) is now widespread in the operating room and in the ICU, especially for preoxygenation before intubation in non-hypoxemic patients. However, no large randomized study has assessed its relevance in this population. Methods: The PROTRACH study is a randomized, multicenter open-labelled, controlled trial, including non-severely hypoxemic patients requiring intubation in medical or surgical ICU. Patients were randomly allocated to receive 4-minute preoxygenation delivered by HFNC or standard high-flow face mask (HFFM) before intubation. HFNC was maintained throughout the intubation procedure whereas HFFM was removed to perform laryngoscopy. The primary outcome was the lowest pulse oximetry throughout the intubation procedure. Secondary outcomes included drop in pulse oximetry, adverse events related to intubation, and outcome in the ICU. Main Findings: A total of 192 patients were randomized. In the intent-to-treat analysis, 184 patients (HFNC n = 95; HFFM n = 89), the median [IQR] lowest pulse oximetry was 100% [97;100] for HFNC and 99 % [95;100] for the HFFM group (P = 0.30). Mild desaturation below 95% was more frequent with HFFM (23%) than with HFNC (12%) (relative risk 0.51, CI 95% [0.26 to 0.99], P = 0.045). There were fewer adverse events in the HFNC group (6%) than in the HFFM group (19%) (relative risk 0.31, CI 95% [0.13 to 0.76], P = 0.007), including significantly fewer severe adverse events, respectively 6 (6%) and 14 (16%) with HFNC and HFFM (relative risk 0.38, CI 95% [0.15 to 0.95], P = 0.03). There was no difference in the outcome in the ICU with a mortality rate of 27% in both groups (P = 0.90). Interpretation: Compared with HFFM, preoxygenation with HFNC in the ICU did not improve the lowest level of pulse oximetry during intubation in the non-severely hypoxemic patients but led to a reduction in severe and moderate intubation-related adverse events. Clinical Trial Number: Clinicaltrials.gov identifier: NCT02700321, Eudra CT: 2015-A00145-44 Funding Statement: The French Ministry of Health (Interregional French Clinical Hospital Research Program grant (PHRCi 2014 - API12/N/077), a grant for research & innovation missions (University Hospital of Nantes) and by Fisher & Paykel Healthcare. Declaration of Interests: Declaration of Interest: Christelle Volteau, Gwenael Colin, Adel Maamar, Vanessa Jean Michel, Pierre Joachim Mahe, Mickael Landais, Noelle Brule, Cedric Bretonniere, Olivier Zambon and Christophe Guitton declare no conflict of interest. Stephan Ehrmann declares receiving consultancy fees from Aerogen Ltd, La Diffusion Technique Francaise and Baxter healthcare and unrestricted research support from Fisher and Paykel, Aerogen Ltd and Hamilton medical. Mickael Vourc’h declares personal fees from MSD, Pfizer, Baxter, grants from Fisher Paykel, outside the submitted work. Ethics Approval Statement: Three methods of consent were available. When possible, capable patients were included after written informed consent. Most patients were included after the written informed consent of their next-of-kin or following an emergency inclusion procedure if not available at the time of inclusion. Then, consent was obtained from all patients as soon as possible after recovery. The appropriate ethics committee (Comite de Protection des Personnes, Rennes, France) approved this study protocol in September 2015 (15/13-975).

ガス供給と電源容量の問題が解決されhigh flow nasal cannula呼吸補助下に施設間陸路搬送した1例(A case of interhospital ground transport with a high flow nasal cannula for respiratory support enabled by the resolution of gas and power supply capacity problems)

要旨High flow nasal cannula（HFNC）療法は様々な医療場面での使用が増加しているが，HFNCを用いた施設間搬送の報告は少ない。これまで当院では，HFNCシステムへの酸素・混合ガス供給とドクターカーの電源容量の問題によりHFNC呼吸補助下の施設間陸路搬送が実施できなかった。しかし，新たなHFNCシステムの導入と，ドクターカーの電源容量増加と補助電源の確保により，HFNCを用いた施設間搬送が可能となった。今回，我々はHFNC呼吸補助下に施設間陸路搬送した症例を経験したので報告する。症例は11か月の男児。Respiratory syncytial virus（RSV）細気管支炎による急性呼吸不全のため当院へ転院し，pediatric intensive care unit（PICU）でHFNC療法が導入された。その後症状が軽快しHFNC呼吸補助下に医療機関へ転院搬送となった。搬送中，呼吸状態の悪化や重篤な副作用を認めず，安全に搬送が行われた。搬送にHFNCを用いる場合，デバイスによっては呼吸器設定に限界があること，屋外使用時はデバイスへの外気温の影響を考慮すること，および複数の医療機器を同時に使用する場合の総電源容量と搬送車両の電源容量を把握するなど留意すべき点がある。今後，症例を蓄積し施設間搬送におけるHFNC療法の安全性と有効性を評価する必要がある。

High Risk Characteristics for Recurrent Cardiovascular Events among Patients with Obstructive Sleep Apnoea in the SAVE Study

BackgroundObstructive sleep apnoea (OSA) is a common comorbidity in patients with cardiovascular (CV) disease. We aimed to identify specific OSA clinical phenotypes relating to risks of serious CV events and response to continuous positive airway pressure (CPAP) treatment. MethodsPost-hoc analyses of the Sleep Apnea Cardiovascular Endpoints (SAVE) study in participants with moderate-to-severe OSA and coronary artery disease (CAD) and/or cerebrovascular disease (CeVD) randomised to CPAP plus usual care or usual care alone. Latent class analysis (LCA) was used to identify OSA clinical phenotypes among 2649 (out of 2687 total) patients with complete data on 19 patient-centered variables, supported by Bayesian information criteria and clinical interpretability. Cox regression models were used to evaluate risks of composite cardiac and stroke outcome events in phenotype groups. Preferential response to CPAP treatment was evaluated using interaction terms as well as the Chi-square test. FindingsLCA identified four OSA clinical phenotypes: CAD alone and with diabetes mellitus (CAD+DM), and CeVD alone and with DM (CeVD+DM), in 39%, 15%, 37% and 9% of participants, respectively. The rates of composite CV events were the highest in CAD+DM phenotype (HR 2.08, 95% CI 1.57–2.76) and for stroke were highest in CeVD+DM phenotype (HR 6.84, 95% CI 3.77–12.42). Adherence to CPAP treatment (nil or <4 h vs ≥4 h in the first two years of the study) was shown to influence the risk of composite CV outcome in the phenotypes (P-interaction = 0.04); CPAP adherent patients of the CeVD+DM phenotype had the lowest risk of CV outcome (P = 0.02). InterpretationHigh risk clinical phenotypes were identified in relation to CV events and response to CPAP treatment, which may allow improved targeting of therapies in OSA patients. FundingThe National Health and Medical Research Council (NHMRC) of Australia, Fisher & Paykel Healthcare, and ResMed.

High‐flow apnoeic oxygenation delivered by LMA or tracheal tube for tracheal resection and reconstruction surgery

SummaryAirway management for tracheal resection and reconstruction can be challenging. 'LET Flow' is a novel technique using a high‐flow oxygen delivery device attached directly to a laryngeal mask or tracheal tube that may provide apnoeic oxygenation during surgery on an open trachea.We report a case where a high‐flow oxygen device, AIRVOTM 2 (Fisher &amp; Paykel Healthcare, Aukland, New Zealand), was attached to a size three laryngeal mask airway and 100% oxygen at a flow‐rate of 40 l.min‐1 delivered across an open trachea. This permitted 42 minutes of uninterrupted surgery in an apnoeic female patient with subglottic tracheal stenosis. Oxygen saturations remained above 96% during the apnoeic period and arterial blood gas parameters within acceptable limits. To avoid possible barotrauma or volutrauma as complete tracheal closure approached, flow was reduced to 10 l.min‐1 followed by laryngeal mask cuff deflation. Mechanical ventilation recommenced at tracheal closure. 'LET Flow' provided optimal surgical conditions by removing an airway device from the operative field. No urgent interruption of surgery or rescue mechanical ventilation was required.

The Optiflow™ interface for chronic CPAP use in children

Continuous positive airway pressure (CPAP) is being increasingly used in children of all age ranges. The limited number of commercially available masks especially in infants and young children may complicate its use and compliance. In this report, we describe our experience with the use of the Optiflow™ (Fisher and Paykel Healthcare) Nasal Cannula attached to a regular CPAP device in the setting of chronic CPAP use. This interface consists of a nasal cannula and was originally designed for the delivery of high-flow oxygen therapy. We could show an objective improvement in breathing parameters in several children selected for CPAP mainly because of obstructive sleep apnea syndrome (OSAS). However, this interface cannot be used for bilevel non-invasive ventilation due to insufficient triggering.

Humidification mitigates acute mucosal toxicity during radiotherapy when factoring volumetric parameters. Trans Tasman Radiation Oncology Group (TROG) RadioHUM 07.03 substudy

Purpose/Objective(s)To model in a subset of patients from TROG 07.03 managed at a single site the association between domiciliary based humidification use and mucositis symptom burden during radiotherapy (RT) for head and neck cancer (HNC) when factoring in volumetric radiotherapy parameters derived from tumour and normal tissue regions of interest. Materials/MethodsFrom June 2008 through June 2011, 210 patients with HNC receiving RT were randomised to either a control arm or humidification using the Fisher & Paykel Healthcare MR880 humidifier. This subset analysis involves patients recruited from Auckland City Hospital treated with a prescribed dose of ≥70 Gy. Regression models included control variables for Planning Target Volume 70 GY (PTV70Gy); Equivalent Uniform Dose (EUD) MOIST and TSV (surrogates of total mucosal and total swallowing volumes respectively). ResultsThe analysis included 39 patients (humidification 20, control 19). There was a significant odds reduction in CTCAE v3.0 functional mucositis score of 0.29 associated with the use of humidification (p<.001). Within the parameters of the model therefore, the risk of a humidification patient being scored as experiencing a one-step increase in functional mucositis was 3.45 times lower (1/0.29) than for control patients. A control patient was 4.17 times more likely to receive an unfavourable nutritional mode score (p<.001). The risk of being admitted to hospital decreased by a factor of 11.11 for humidification patients (p=.013). ConclusionThe results support the hypothesis that humidification can help mitigate mucositis symptom burden. Radiotherapy dosimetric parameters assist in the evaluation of toxicity interventions.

A Preliminary Analysis of the Incidence of Transfusion-Related Acute Lung Injury (TRALI) in a Sheep Model Following Transfusion with the Supernatant from Leukodepleted Red Cell Units

IntroductionDespite the introduction of risk reduction strategies, transfusion-related acute lung injury (TRALI) continues to be a significant cause of morbidity and mortality. TRALI development may be associated with the transfusion of anti-leucocyte antibodies or biological response modifiers (BRMs). Our group has previously developed a model in which the development of TRALI in lipopolysaccharide (LPS) treated sheep was precipitated by the transfusion of pooled supernatant from date-of-expiry (day (d) 42) packed red blood cell (PRBC) units. This work pre-dated the introduction of pre-storage leukodepletion of PRBCs in Australia, therefore we investigated whether TRALI would still develop in LPS-treated sheep transfused with supernatant from d42 leukodepleted PRBCs.MethodsOn either d2 (n=75 units) or d42 (n=113 units) of storage, leukodepleted PRBCs underwent dual centrifugation to obtain acellular supernatants. Two supernatant pools (d2 and d42) were then prepared by pooling and heat-treating (56°C for 30min) the supernatants. Levels of potential BRMs in the PRBC supernatant pools were characterised using cytometric bead array and ELISA. Instrumented sheep (n=14) were infused with LPS then transfused (10% v/v) with either d2 (n=7) or d42 (n=7) pooled PRBC supernatant. Two hours later sheep were euthanized and post-mortem lung samples were collected. Physiological data were recorded continuously and then averaged in 30 minute blocks for these preliminary analyses. Blood and broncoalveolar lavage (BAL) fluid samples were collected at specific intervals. Blood samples were used for arterial blood gas analyses, coagulation tests (ROTEM), platelet function tests (MultiPlate) and ELISAs. TRALI was defined by hypoxemia (PaO2/FiO2 < 300 on arterial blood gas) and histological evidence of pulmonary edema (by two blinded histopathological assessments of hematoxylin and eosin stained lung sections). Data were compared by group (sheep transfused with d2 PRBC supernatant vs. d42 PRBC supernatant) and by outcome (sheep who developed TRALI vs. those who did not) with either t-tests or 2-way ANOVAs as appropriate.Results and DiscussionStorage duration of leukodepleted PRBC was associated with increased levels of the potential BRMs 5-HETE, 12-HETE, 15-HETE and IL-8, but not soluble CD40 ligand. Only 3 sheep developed TRALI: one transfused with d2 leukodepleted PRBC supernatant and two transfused with d42 leukodepleted PRBC supernatant corresponding to an incidence of 14% and 29% respectively. This indicated a reduced incidence of TRALI in the sheep model compared to previous data using supernatant from d42 non-leukodepleted PRBC which resulted in an incidence of 75% (Tung et al. Vox Sanguinis. 2011). Preliminary analyses of the physiological data revealed a number of differences. Heart rate (P<0.001), blood pressure (P=0.003), pulmonary artery pressure (P<0.001), cardiac output (P<0.001) and PaO2/FiO2 (P<0.001) were different between sheep transfused with either d2 or d42 PRBC supernatant. Heart rate (P<0.001), pulmonary artery pressure (P<0.001), pulse oximeter oxygen saturation (P=0.003), cardiac output (P<0.001) and PaO2/FiO2 (P<0.001) were different between sheep that developed TRALI and sheep that did not. However, given the complexity of these data, further analyses using mixed effects modelling are required to better understand these differences. Sheep transfused with d42 PRBC supernatant had reduced IL-1β lung gene expression and reduced ADP-induced platelet aggregation (both total and area under curve) compared to sheep transfused with d2 PRBC supernatant (P=0.047, 0.012 and 0.028 respectively). In addition, sheep that developed TRALI had worse lung histology scores as well as reduced collagen-induced platelet aggregation (both total and area under curve) compared to sheep who did not develop TRALI (P=0.024, 0.049 and 0.018 respectively).ConclusionsComparison of these results to previously published data from the sheep model is suggestive that pre-storage leukodepletion of PRBCs is associated with a reduced incidence of TRALI. Unsurprisingly, the development of TRALI was associated with worsened respiratory function (oxygen saturation and PaO2/FiO2) and lung histology scores, while changes in hemodynamics and platelet function were also observed. DisclosuresFraser:Fisher and Paykel Healthcare: Consultancy, Other: Provision of equipment for research use, Research Funding; De Motu Cordis: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Optimizing the success of surgeons innovating and commercializing ideas: 10 lessons learned

Michael Blackhurst is a salaried employee in the role of General Manager of the Surgical Product Group of Fisher and Paykel Healthcare Limited.

Postoperative hypothermia and surgical site infection following peritoneal insufflation with warm, humidified carbon dioxide during laparoscopic colorectal surgery: a cohort study with cost-effectiveness analysis

BackgroundSurgical Site Infection (SSI) occurs in 9 % of laparoscopic colorectal surgery. Warming and humidifying carbon dioxide (CO2) used for peritoneal insufflation may protect against SSI by avoiding postoperative hypothermia (itself a risk factor for SSI). This study aimed to assess the impact of CO2 conditioning on postoperative hypothermia and SSI and to perform a cost-effectiveness analysis.MethodsA retrospective cohort study of patients undergoing elective laparoscopic colorectal resection was performed at a single UK specialist centre. The control group (n = 123) received peritoneal insufflation with room temperature, dry CO2, whereas the intervention group (n = 123) received warm, humidified CO2 (using HumiGard™, Fisher & Paykel Healthcare). The outcomes were postoperative hypothermia, SSI and costs. Multivariate analysis was performed.ResultsA total of 246 patients were included in the study. The mean age was 68 (20–87) and mean BMI 28 (15–51). The primary diagnosis was cancer (n = 173), and there were no baseline differences between the groups. CO2 conditioning significantly decreased the incidence of postoperative hypothermia (odds ratio 0.10, 95 % CI 0.04–0.23), with hypothermic patients found to be at increased risk of SSI (odds ratio 4.0, 95 % CI 1.25–12.9). Use of conditioned CO2 significantly decreased the incidence of SSI by 66 % (p = 0.04). The intervention group incurred costs of £155 less per patient. The incremental cost-effectiveness ratio was negative.Conclusion CO2 conditioning during laparoscopic colorectal surgery is a safe, feasible and a cost-effective intervention. It improves the quality of surgical care relating to SSI and postoperative hypothermia.

Effect of non-invasive oxygenation strategies in immunocompromised patients with severe acute respiratory failure: a post-hoc analysis of a randomised trial

The use of non-invasive ventilation is controversial in immunocompromised patients with acute respiratory failure, whereas the use of high-flow nasal cannula oxygen therapy is growing as an alternative to standard oxygen. We aimed to compare outcomes of immunocompromised patients with acute respiratory failure treated with standard oxygen with those treated with high-flow nasal cannula oxygen alone or high-flow nasal cannula oxygen associated with non-invasive ventilation. We did a post-hoc subgroup analysis in a subset of immunocompromised patients with non-hypercapnic acute respiratory failure from a multicentre, randomised, controlled trial. In the trial, patients from 23 intensive care units in France and Belgium were randomly assigned (1:1:1) to receive either standard oxygen, high-flow nasal cannula alone, or non-invasive ventilation interspaced with high-flow nasal cannula between non-invasive ventilation sessions (non-invasive ventilation group). Patients with profound neutropenia, acute-on-chronic respiratory failure, cardiogenic pulmonary oedema, shock, or altered consciousness were excluded. The primary outcome was the proportion of patients who required endotracheal intubation within 28 days after randomisation. Of the 82 immunocompromised patients, 30 were treated with standard oxygen, 26 with high-flow nasal cannula alone, and 26 with non-invasive ventilation plus interspaced high-flow nasal cannula. 8 (31%) of 26 patients treated with high-flow nasal cannula alone, 13 (43%) of 30 patients treated with standard oxygen, and 17 (65%) of 26 patients treated with non-invasive ventilation required intubation at 28 days (p=0·04). Odds ratios (ORs) for intubation were higher in patients treated with non-invasive ventilation than in those treated with high-flow nasal cannula: OR 4·25 (95% CI 1·33-13·56). ORs were not significantly different between patients treated with high-flow nasal cannula alone and standard oxygen: OR 1·72 (0·57-5·18). After multivariable logistic regression, the two factors independently associated with endotracheal intubation and mortality were age and use of non-invasive ventilation as first-line therapy. Non-invasive ventilation might be associated with an increased risk of intubation and mortality and should be used cautiously in immunocompromised patients with acute hypoxaemic respiratory failure. French Ministry of Health, the French societies of intensive care (Société de Réanimation de Langue Française, SRLF) and pneumology (Société de Pneumologie de Langue Française, SPLF), La Mutuelle de Poitiers, AADAIRC (Association pour l'Assistance à Domicile Aux Insuffisants Respiratoires Chroniques), and Fisher&Paykel Healthcare.

Use of Optiflow high flow nasal oxygen therapy in a patient requiring emergency neurosurgery

SummaryA patient in their ninth decade of life presented with a life threatening head injury resulting in a reduced level of consciousness and severe pneumonia. Invasive ventilation and peri‐operative critical care were deemed not in the patient's best interest. We utilised high flow nasal oxygen therapy via an Optiflow device (Fisher and Paykel Healthcare, New Zealand) that significantly addressed hypoxic respiratory failure, allowing emergency neurosurgical intervention to be performed under local anaesthesia and sedation. The patient survived to hospital discharge.

The use of nasal high flow oxygen to aid the management of respiratory failure and obesity in a district general maternity unit

SummaryNasal high flow (NHFTM) oxygen using the OptiflowTM system (Fisher &amp; Paykel Healthcare Limited, Panmure, Auckland, New Zealand) is frequently used in our hospital in the management of type one respiratory failure. We present two cases where we have used NHFTM in our maternity unit. In the first case, this was used in the management of respiratory failure and as an adjunct at induction of general anaesthesia, and in the second, to facilitate safe neuraxial anaesthesia in a morbidly obese patient. Our experience of this equipment has prompted our department to consider its use beyond managing respiratory failure in critical care but also an adjunct for use in the operating theatres and maternity unit.

Raising the standard of care for oxygen delivery with nasal high flow in high-acuity areas—a controlled study

Nasal high-flow therapy and dispersion of nasal aerosols in an experimental setting Sally Roberts, N. Kabaliuk, Cjt Spence, Jane O'Donnell, Z. Zulkhairi Abidin, R. Dougherty, S. Roberts, Y. Jiang, Mc Jermy University of Canterbury, New Zealand Fisher & Paykel Healthcare, New Zealand University of KS, USA Auckland District Health Board, New Zealand University of Auckland, New Zealand Background/Purpose: Nasal high-flow (NHF) therapy delivers flows of heated and humidified gases up to 60 L/min via a nasal cannula. NHF is widely used to support patients, including those who may be infectious. It is thought that NHF gas flow velocities may increase cross-infection risk. Methods: Aerosols within the exhaled breath of healthy volunteers were imaged. Experimental breathing conditions deemed as typical patient breathing conditions were tested: at rest, with a violent exhalation (snorting), both with and without NHF, at flows of 30 and 60 L/min, and for both separate nostrils. The number, diameter, evaporation rates, and velocity of exhaled aerosols were collected. Results: The numbers of aerosols measured were greatest during a violent exhalation without NHF and reduced with NHF. The numbers of aerosols were higher at 60 than 30 L/min, suggesting that higher gas flow rates may be associated with increased aerosol production; however, the numbers were on average 43% and 56% less than without NHF, respectively. During breathing at rest, no differences were imaged between with and without NHF, except at 60 L/min where numbers of aerosols produced were equivalent to 10% of a violent exhalation. Aerosol trajectory and evaporation rates observed both with and without NHF predicted that aerosols between 25 and 250 μm may travel up to 4.4 m and remain airborne for 43 seconds. Conclusions: NHF use does not increase the risk of dispersing infectious aerosols above the risk of typical patient breathing with violent exhalation, which is the worst-case clinical scenario; therefore, standard risk control measures should apply.

Nasal high-flow therapy and dispersion of nasal aerosols in an experimental setting

Nasal high-flow therapy and dispersion of nasal aerosols in an experimental setting Sally Roberts, N. Kabaliuk, Cjt Spence, Jane O'Donnell, Z. Zulkhairi Abidin, R. Dougherty, S. Roberts, Y. Jiang, Mc Jermy University of Canterbury, New Zealand Fisher & Paykel Healthcare, New Zealand University of KS, USA Auckland District Health Board, New Zealand University of Auckland, New Zealand Background/Purpose: Nasal high-flow (NHF) therapy delivers flows of heated and humidified gases up to 60 L/min via a nasal cannula. NHF is widely used to support patients, including those who may be infectious. It is thought that NHF gas flow velocities may increase cross-infection risk. Methods: Aerosols within the exhaled breath of healthy volunteers were imaged. Experimental breathing conditions deemed as typical patient breathing conditions were tested: at rest, with a violent exhalation (snorting), both with and without NHF, at flows of 30 and 60 L/min, and for both separate nostrils. The number, diameter, evaporation rates, and velocity of exhaled aerosols were collected. Results: The numbers of aerosols measured were greatest during a violent exhalation without NHF and reduced with NHF. The numbers of aerosols were higher at 60 than 30 L/min, suggesting that higher gas flow rates may be associated with increased aerosol production; however, the numbers were on average 43% and 56% less than without NHF, respectively. During breathing at rest, no differences were imaged between with and without NHF, except at 60 L/min where numbers of aerosols produced were equivalent to 10% of a violent exhalation. Aerosol trajectory and evaporation rates observed both with and without NHF predicted that aerosols between 25 and 250 μm may travel up to 4.4 m and remain airborne for 43 seconds. Conclusions: NHF use does not increase the risk of dispersing infectious aerosols above the risk of typical patient breathing with violent exhalation, which is the worst-case clinical scenario; therefore, standard risk control measures should apply.

PTH-334 Cost-effectiveness of warm humidified co2 to reduce surgical site infections in laparoscopic colorectal surgery: a cohort study

Introduction Surgical Site Infections (SSI) are a common complication which negatively impact on patient quality of life and constitute a financial burden to healthcare providers. The objective of this study is to evaluate whether using warmed, humidified carbon dioxide for peritoneal insufflation decreases the incidence of SSIs, improves patient safety and provides value for money. Method A retrospective cohort study of patients undergoing elective laparoscopic colorectal resection for both benign and malignant disease was performed at a single UK specialist centre from September 2012 to July 2014. The control group (n = 126) received peritoneal insufflation with standard cold, dry carbon dioxide whereas the intervention group (n = 126) received peritoneal insufflation with warmed, humidified carbon dioxide (using HumiGard TM , Fisher&Paykel Healthcare). All patients had standard prophylactic antibiotic therapy on induction. The primary outcome measures were incidence of SSI and costs (standard-of-care costs, intervention costs and SSI treatment costs incurred at an average cost of £2000 per SSI). The intervention was assessed by calculating the Risk Ratio (RR), Odds Ratio (OR) and incremental cost-effectiveness ratio (ICER) per infection-free patient gained. Results Median age was 68 (20–87). The median BMI was 27 (SD 5.98). The mean operation time was 211 min (SD 92.7), M:F ratio was 1:1. The primary diagnoses were as follows: cancer n = 174, diverticulitis n = 31, Crohn’s n = 15, ulcerative colitis n = 10, other n = 22. There was no significant variation in age, BMI, sex, smoking status, operation time or conversion rates between groups. Introduction of warmed, humidified carbon dioxide for peritoneal insufflation reduced the incidence of SSI from 12% to 4.7% (RR = 0.40; p = 0.049; 95% CI: 0.160 – 0.997 and OR = 0.37; p = 0.047; 95% CI = 0.138 – 0.987). Treatment costs including SSI costs for patients in the control group amounted to approximately £31000 compared to £21500 in the intervention group. The ICER for the intervention is -£1226, the negative number indicating a net reduction in costs in addition to decreased SSI incidence. It costs on average £1226 less to generate each additional infection-free patient using the intervention. Conclusion This study indicates that warmed, humidified carbon dioxide is superior to cold, dry carbon dioxide for peritoneal insufflation in laparoscopic colorectal surgery. The intervention appears to be cost-effective whilst decreasing surgical morbidity. Disclosure of interest None Declared.

Volume Oscillations Delivered to a Lung Model Using 4 Different Bubble CPAP Systems.

High-frequency pressure oscillations created by gas bubbling through an underwater seal during bubble CPAP may enhance ventilation and aid in lung recruitment in premature infants. We hypothesized that there are no differences in the magnitude of oscillations in lung volume (ΔV) in a preterm neonatal lung model when different bubble CPAP systems are used. An anatomically realistic replica of an infant nasal airway model was attached to a Silastic test lung sealed within a calibrated plethysmograph. Nasal prongs were affixed to the simulated neonate and supported using bubble CPAP systems set at 6 cm H2O. ΔV was calculated using pressure measurements obtained from the plethysmograph. The Fisher & Paykel Healthcare bubble CPAP system provided greater ΔV than any of the other devices at all of the respective bias flows (P < .05). The Fisher & Paykel Healthcare and Babi.Plus systems generally provided ΔV at lower frequencies than the other bubble CPAP systems. The magnitude of ΔV increased at bias flows of > 4 L/min in the Fisher & Paykel Healthcare, Airways Development, and homemade systems, but appeared to decrease as bias flow increased with the Babi.Plus system. The major finding of this study is that bubble CPAP can provide measureable ventilation effects in an infant lung model. We speculate that the differences noted in ΔV between the different devices are a combination of the circuit/nasal prong configuration, bubbler configuration, and frequency of oscillations. Additional testing is needed in spontaneously breathing infants to determine whether a physiologic benefit exists when using the different bubble CPAP systems.

Phase 3 Trial of Domiciliary Humidification to Mitigate Acute Mucosal Toxicity During Radiation Therapy for Head-and-Neck Cancer: First Report of Trans Tasman Radiation Oncology Group (TROG) 07.03 RadioHUM Study

To assess the impact of domicile-based humidification on symptom burden during radiation therapy (RT) for head-and-neck (H&N) cancer. From June 2007 through June 2011, 210 patients with H&N cancer receiving RT were randomized to either a control arm or to receive humidification using the Fisher & Paykel Healthcare MR880 humidifier. Humidification commenced on day 1 of RT and continued until Common Terminology Criteria for Adverse Events (CTCAE), version 3.0, clinical mucositis (CMuc) grade ≤1 occurred. Forty-three patients (42%) met a defined benchmark for humidification compliance and contributed to per protocol (PP) analysis. Acute toxicities, hospitalizations, and feeding tube events were recorded prospectively. The McMaster University Head and Neck Radiotherapy Questionnaire (HNRQ) was used for patient-reported outcomes. The primary endpoint was area under the curve (AUC) for CMuc grade ≥2. There were no significant differences in AUC for CMuc ≥2 between the 2 arms. Humidification patients had significantly fewer days in hospital (P=.017). In compliant PP patients, the AUC for CTCAE functional mucositis score (FMuc) ≥2 was significantly reduced (P=.009), and the proportion who never required a feeding tube was significantly greater (P=.04). HNRQ PP analysis estimates also in the direction favoring humidification with less symptom severity, although differences at most time points did not reach significance. TROG 07.03 has provided efficacy signals consistent with a role for humidification in reducing symptom burden from mucositis, but the influence of humidification compliance on the results moderates recommendations regarding its practical utility.

Successful Nasal Continuous Positive Airway Pressure for Newborn Respiratory Distress in a Regional Centre

We wish to present our experience using nasal continuous positive airway pressure (nCPAP) in a regional town over a 5-year period. Kalgoorlie is located 595 km east of Perth in Western Australia, with a population of 31 107. With over 800 deliveries each year, around 100 infants require nursery care annually. The level 2 nursery caters for babies born 34 weeks and over with the intent to transfer those <34 weeks gestation in utero to the tertiary centre. Prior to 2008, most neonates presenting with respiratory distress were transferred to Perth. In 2008, the team of three paediatricians started offering nCPAP therapy for infant respiratory distress. The Western Australian Neonatal Network facilitated up-skilling of nurses with CPAP training as well as a 1–2 week rotation at the tertiary hospital. A process of ongoing training for nurses and junior doctors supervised by a paediatrician and neonatal nurse was commenced at Kalgoorlie. Bubble CPAP was commenced using Hudson prongs and Fisher and Paykel Healthcare Bubble CPAP System. We adhered to the King Edward Memorial Hospital Neonatal guidelines for CPAP.1 A paediatrician was available on site during working hours and as Kalgoorlie is a small town geographically could attend to emergencies out of hours within10 min. Fifty-five babies were treated with CPAP when they developed respiratory distress. Of these, over half were term gestation, 14 (25%) 35–37 weeks gestation and 11 (20%) 32–34 weeks. The conditions requiring nCPAP were transient tachypnoea of the newborn, hyaline membrane disease, meconium aspiration syndrome, sepsis and birth asphyxia. None of the babies developed nasal trauma or pneumothorax while on CPAP. The majority 37 (67%) were discharged home without needing transfer to a tertiary centre (Fig. 1). Eighteen babies (33%) were transferred to the tertiary hospital. In eight instances, there was shortage of nursing staff; seven were sent for further investigations and management of complex conditions. Disposition of babies treated with nCPAP. Nasal CPAP is safe and effective therapy for infant respiratory distress even in a regional hospital.2 With adequate training of the staff and availability of paediatrician cover, nCPAP therapy reduces the number of transfers to tertiary facility. Although we acknowledge there was a small number treated over 5 years, our experience suggests that nCPAP is a feasible treatment option for late preterm and term infants even in regional centres.

Comparison of the pharyngeal pressure provided by two heated, humidified high‐flow nasal cannulae devices in premature infants

This study aims to determine if there is a difference in the pharyngeal pressure, measured as a surrogate for continuous positive distending airway pressure, delivered to premature infants between two commonly used heated, humidified high-flow nasal cannulae (HHHFNC) devices: Fisher & Paykel Healthcare HHHFNC and Vapotherm 2000i. Pharyngeal pressure measurements were taken from stable premature infants receiving HHHFNC for respiratory support. Flow rates of 2-8 L/min were studied. Nine infants had pharyngeal pressure measurements recorded with both HHHFNC devices at flow rates of 2-8 L/min. There was no difference in pharyngeal pressures recorded between devices at flow rates of 2-6 L/min; measured pressure was linearly associated with flow (R(2) = 0.9). At flow rates of 7 L/min, Vapotherm delivered a mean (standard deviation) pharyngeal pressure of 4.7 (2.2) cmH2 O compared with 4.23 (2.2) cmH2 O by the Fisher & Paykel device (P = 0.04). At a flow of 8 L/min, the mean pharyngeal pressure via Vapotherm was 4.9 (2.2) cmH2 O compared with 4.1 (2.3) cmH2 O with the Fisher & Paykel device (P = 0.05). Both HHHFNC delivered similar pharyngeal pressures at flow rates of 2-6 L/min. The pressure limiter valve of the Fisher & Paykel device attenuated the pharyngeal pressures at flows of 7 and 8 L/min. Vapotherm trended towards higher delivered pharyngeal pressure at flow rates 7 and 8 L/min, but the clinical significance of the difference remains unclear.