Respiratory Management Strategies Research Articles

Perioperative respiratory complications: current evidence and strategy discussed in 2017 JA symposium.

Respiratory management during general anesthesia aims to safely secure the airway and maintain adequate ventilation to deliver oxygen to the vital organs, maintaining homeostasis even during surgery. Despite its clinical importance, anesthesiologists often encounter difficulties in properly managing respiration during the perioperative period, leading to severe respiratory complications. In this year's JA symposium, 5 editorial board members of Journal of Anesthesia (JA) who are experts in the field of respiratory management in anesthesia discussed the following topics: quitting smoking before surgery: exposure to passive smoke is damaging to children, ventilator-associated pneumonia, high inspiratory oxygen concentration and lung injury, aspiration pneumonia, and postoperative respiratory management strategy in patients with obstructive sleep apnea. We hope that this special article regarding this year's JA symposium may be useful for JA readers to manage clinical anesthesia on a daily basis.

The survival of extremely and very preterm infants and advance in respiratory support

Extremely and very preterm infants(EPI and VPI) have high mortality and morbidity mainly caused by their lung immaturity and easy to develop bronchopulmonary dysplasia.Antenatal and postnatal respiratory management strategies are associated with their survival and long term outcomes.Antenatal steroids, surfactant therapy and ventilation strategies have shown the potential to improving the outcomes of EPI and VPI.Non-invasive ventilation especially continuous positive airway pressure started at or soon after birth with subsequent selective surfactant administration may be considered as an alternative to routine intubation with prophylactic or early surfactant administration in such preterm infants.New strategies of ventilation such as high frequency oscillatory ventilation, neutrally adjusted ventilator assist and volume targeted ventilation will be explored. Key words: Extremely preterm infants; Very preterm infants; Mortality; Respiratory management

Evidence-based respiratory management strategies required to prevent complications and improve outcome in acute spinal cord injury patients

Spinal injuries without neurological damage have little effects on respiratory function unless associated with injury to the chest wall. Early verticalisation or mobilisation of these patients is safe and likely to improve vital capacity. Spinal injury with cord damage has a profound effect on the mechanics of respiration and on respiratory function particularly in cervical cord injuries. Around 40% of spinal cord injuries occur in the cervical spine, a trend that is steadily increasing, with respiratory causes being responsible for death in over 20% of individuals. Loss of lung volumes and relative hypoxemia contribute to global hypoxaemia, exacerbating cord ischaemia in the acute period. Respiratory compromise results in the loss of muscle strength generation capacity and reduced lung volumes and in particular vital capacity, of up to 70%, ineffective cough and secretion clearance abilities; reductions in both lung and chest wall compliance and an additional oxygen cost of breathing due to changes in respiratory mechanics, with obstructive sleep apnoea evident in over 50% of acute tetraplegics. While some countries have specialist spinal centres to manage such catastrophic trauma with a demonstrable improvement in health outcomes attributed to their contribution, many individuals are initially admitted to local hospitals where healthcare professionals are less likely to fully appreciate the significant and continued vulnerabilities of such individuals. This article aims to provide a basic understanding of the causes and identification of the main principles of the respiratory management strategies required to maintain pulmonary health for cervical spinal cord injury patients during the initial and early post trauma phase.

TH-AB-303-08: Dealing with Erratic Motion: Respiratory Gating Using Internal Surrogates in Pancreatic SBRT

Purpose: The pancreas undergoes erratic and unstable respiratory-induced motion, which hinders respiratory gating and makes dose escalation difficult. In this study, we demonstrate the accuracy and dosimetric impact of respiratory gating using the instantaneous location of fiducial markers (internal gating) compared to conventional techniques for pancreatic tumors during SBRT. Methods: Motion data from 97 pancreatic SBRT treatments were retrospectively analyzed. In each, the daily trajectory of the tumor was reconstructed by calculating a Gaussian probability density function using the location of gold fiducial markers in the CBCT projections. The uncertainty in position for each phase of the respiratory cycle was given as the mean width of the Gaussian PDF. Using the calculated trajectories, we investigated the dosimetric impact of several respiratory motion management strategies, including conventional gating using an external chest block, and internal gating using the fiducial marker location. Results: End-exhale was the most consistent phase, with a mean variance of 0.14±0.14 mm (95% CI 0.04–0.65 mm), whereas max inhale was the least consistent (mean variance 0.34±0.36 mm, 95% CI 0.06–1.46 mm). In a simulated clinical scenario, fiducial-based internal gating using a 2mm superior-inferior window greatly outperformed the conventional approach using external markers (p<0.001), with a mean target D95 of 99.0±2.0%, 95% CI 92.7–100% (conventional gating – D95 96.6±7.4%, 95% CI 68.4–100%). Internal gating also increased the duty cycle from 30% to 45%. Conclusions: Pancreatic motion correlates weakly with chest wall motion, and makes conventional gating less accurate. Fiducial markers are easily discernable in kV imaging, and can provide accurate information regarding the instantaneous tumor location. By acquiring sequential kV images during pancreatic SBRT, the tumor location can be measured, and the treatment beam can be gated using this information. In a clinical dataset of 97 SBRT treatments, this protocol resulted both greater accuracy and a higher duty cycle. This work was funded in part by the National Institutes of Health, the American Cancer Society, and Varian Medical Systems.

Perioperative management of carinal pneumonectomy: a retrospective review of 13 patients.

Carinal pneumonectomy is a challenging procedure because of the difficulties in surgical technique, intraoperative airway management, and postoperative respiratory and anastomotic complications. However, information regarding the anesthetic and intraoperative respiratory management of this procedure is scarce. This report describes our routine anesthetic and respiratory management strategy in patients undergoing carinal pneumonectomy. Medical records of 13 patients who underwent carinal pneumonectomy under combined general and epidural anesthesia between 2008 and 2012 were analyzed retrospectively. Eleven patients underwent right carinal pneumonectomy and two underwent left carinal pneumonectomy. A left double-lumen tube was used in all but one case, in which endobronchial intubation was difficult because of intrabronchial invasion of the tumor. A 6.0-mm-long reinforced endobronchial tube was intubated into the main bronchus of the non-operative side from the surgical field during carinal resection. There were no episodes of severe hypoxemia or hypercapnia during surgery. Twelve patients were extubated immediately after surgery. No patient developed post-thoracotomy acute lung injury or required postoperative reintubation despite poor preoperative respiratory function. The 30-day mortality rate was 0%. Our airway management protocol for carinal pneumonectomy enables positive surgical outcomes.

Modifiable risk factors for preterm brain injury

Abstract The prevalence of preterm birth is increasing globally and it is a leading cause of neurodevelopmental impairment in childhood. Preterm brain injury consists predominantly of: white matter disease, which may be diffuse or cystic and is usually accompanied by grey matter alterations; and haemorrhagic lesions (germinal matrix haemorrhage–intraventricular haemorrhage). The evidence base for neuroprotective strategies has grown in recent years. Antenatal interventions include the use of corticosteroids and magnesium sulphate, and organisation of maternity services so that early postnatal transfer is avoided. Postnatal interventions associated with improved neurological outcome include delayed clamping of the umbilical cord, respiratory management strategies that reduce the incidence of pneumothorax and bronchopulmonary dysplasia, avoidance of hypotension and hypocarbia, feeding practices that promote human milk intake, caffeine therapy, avoidance of early relatively high dose postnatal dexamethasone, and minimising the incidence of postnatal sepsis. In this review, we describe the predominant forms of preterm brain injury in the current era and consider the evidence base for clinical practices designed to reduce brain injury and adverse outcome after preterm birth.

The potential role of respiratory motion management and image guidance in the reduction of severe toxicities following stereotactic ablative radiation therapy for patients with centrally located early stage non-small cell lung cancer or lung metastases.

Image guidance allows delivery of very high doses of radiation over a few fractions, known as stereotactic ablative radiotherapy (SABR). This treatment is associated with excellent outcome for early stage non-small cell lung cancer and metastases to the lungs. In the delivery of SABR, central location constantly poses a challenge due to the difficulty of adequately sparing critical thoracic structures that are immediately adjacent to the tumor if an ablative dose of radiation is to be delivered to the tumor target. As of current, various respiratory motion management and image guidance strategies can be used to ensure accurate tumor target localization prior and/or during daily treatment, which allows for maximal and safe reduction of set up margins. The incorporation of both may lead to the most optimal normal tissue sparing and the most accurate SABR delivery. Here, the clinical outcome, treatment related toxicities, and the pertinent respiratory motion management/image guidance strategies reported in the current literature on SABR for central lung tumors are reviewed.

Transitional hemodynamics in preterm infants with a respiratory management strategy directed at avoidance of mechanical ventilation

BackgroundEarly respiratory management of very low birth weight infants has changed over recent years to a practice of early use of CPAP with early selective surfactant administration, and decreased use of mechanical ventilation. One strategy is to use the combination of surfactant and prompt extubation to nasal continuous positive airway pressure (INtubate, SURfactant, Extubate, or INSURE). The aim of this study is to describe blood flow and ductal flow in a prospective cohort during the transitional period when this respiratory management strategy is used. MethodsInborn infants <29week gestation underwent INSURE within 30min of birth using 200mg/kg Curosurf. Blood pressure and blood flow parameters (RVO, LVO, SVC flow, ductus arteriosus) were measured at 6, 24 and 72h of age and information on morbidity was collected. ResultsSixty-eight infants with a median (range) weight of 940 (450–1380) g were studied. 13 (19%) patients needed mechanical ventilation within 72h of life (INSURE failure). Blood flows and blood pressure were within reported ranges. Eleven (16%) patients had a blood pressure <gestational age and 9 (13%) patients had low blood flow. ConclusionThese data show a low prevalence of low blood pressure and low blood flow in the first 3days after INSURE as compared to cohorts where mechanical ventilation was preferred during transition. We speculate that altered ventilation strategies have helped decrease the incidence of low blood flow and low blood pressure.

The role of non-invasive ventilation in blunt chest trauma: systematic review and meta-analysis.

Respiratory support is the mainstay for the management of patients with pulmonary contusion following blunt chest trauma. In patients not requiring immediate intubation and ventilation, the optimal respiratory management strategy is not clear. This systematic review and meta-analysis aimed to determine the efficacy of non-invasive ventilation (NIV), as compared to traditional respiratory support strategies (i.e., high-flow facemask oxygen or pre-emptive intubation and ventilation), in adult patients with blunt chest trauma. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing NIV to traditional forms of respiratory support (i.e., facemask oxygen or intubation and ventilation) in an adult trauma population. For each eligible trial, we extracted the outcomes of all-cause mortality, length of intensive care unit (ICU) stay, length of hospital stay, and pneumonia. We identified 643 citations, selected 17 for full-text evaluation, and identified three eligible RCTs. Patients receiving NIV had a non-significant reduction in the risk of death (OR 0.55; 95% CI 0.18-1.70; I (2)=0%), but significant reductions in length of ICU stay (mean difference -2.45days; 95% CI -4.27 to -0.63; I (2)=66%), length of hospital stay (mean difference -4.60days; 95% CI -8.81 to -0.39; I (2)=85%), and risk of pneumonia (OR 0.20; 95% CI 0.09-0.47; I (2)=0%). This meta-analysis suggests that NIV is superior to both high-flow facemask oxygen or pre-emptive intubation and ventilation in patients with blunt chest trauma who have no contraindication to NIV.

Safety and Long Term Outcomes with High Flow Nasal Cannula Therapy in Neonatology: A Large Retrospective Cohort Study.

High flow nasal cannula therapy (HFT) has been shown to be similar to nasal continuous positive airway pressure (nCPAP) in neonates with respect to avoiding intubation. The objective of the current study is to determine if there are trends for adverse safety and long-term respiratory outcomes in very low birth weight infants (<1500 g) from centers using HFT as their primary mode of non-invasive respiratory support compared to data from the largest neonatal outcomes database (Vermont Oxford Network; VON). A multicenter, retrospective analysis of pulmonary outcomes data was performed for the calendar years 2009, 2010 and 2011. Performance of five HFT centers was compared with population outcomes from the VON database. The five HFT centers routinely use flow rates between 4-8 L/min as described by the mechanistic literature. Weighted average percentages from the five HFT centers were calculated, along with the 95% confidence intervals (CI) to allow for comparison to the VON means. Patient characteristics between the HFT centers and the VON were not different in any meaningful way, despite the HFT having a greater percentage of smaller infants. The average VON center primarily used nCPAP (69% of all infants) whereas the HFT centers primarily used HFT (73%). A lesser percentage of VLBW infants in the HFT cohort experienced mortality and nosocomial infection. Compared to VON data, an appreciably lesser percent of the HFT cohort were receiving oxygen at 36 weeks and less went home on oxygen. Considering there was no trend for adverse events, and there was a trend for better outcomes pertaining to long-term oxygen use, these data support claims of safety for HFT as a routine respiratory management strategy in the NICU.

The Role of Active Breathing Control-Moderate Deep Inspiration Breath-Hold (ABC-mDIBH) Usage in non-Mastectomized Left-sided Breast Cancer Radiotherapy: A Dosimetric Evaluation

The aim of this study is to evaluate the dosimetric impact of utilizing Active Breathing Control-moderate deep inspiration breath-hold (ABC-mDIBH) technique in early-stage left-sided breast cancer radiotherapy (RT). Twenty-five patients with left-sided early-stage breast cancer undergoing breast-conserving surgery referred to our department for adjuvant radiotherapy between October 2010 and October 2011 were scanned with computed tomography (CT)-simulator at free breathing (FB) and ABC-mDIBH for radiation treatment planning. Two separate treatment plans were generated for each patient, with and without ABC-mDIBH to comparatively evaluate dose-volume parameters of both plans. Dose-volume parameters of lung, heart, left anterior descending artery (LAD), contralateral breast and spinal cord were significantly reduced with ABC-mDIBH compared to free breathing (p< 0.001). The use of ABC-mDIBH technique in the practice of early-stage left-sided breast cancer radiotherapy improves critical organ sparing with the dosimetrically-confirmed potential to decrease treatment-related morbidity and mortality. This respiratory management strategy is a promising tool that may be routinely used for the tre

Respiratory management strategies for Duchenne muscular dystrophy: practice variation amongst canadian sub‐specialists

Respiratory management of Duchenne muscular dystrophy (DMD) is not well studied and may vary across centers and practitioners. Our objective was to describe and compare the respiratory management practices of Canadian Pediatric Respirologists and Neuromuscular specialists for children with DMD. A web-based survey was sent to all 56 practicing Canadian Pediatric Respirologists and to all 24 members of the Canadian Pediatric Neuromuscular Group (CPNG) who follow children with neuromuscular diseases. The survey included 28 questions about timing and indications for respiratory consultation, sleep disordered breathing (SDB) assessments, and treatments. Thirty eight (68%) pediatric respirologists and 17 (71%) CPNG members responded. Respirologists provide initial consultation after a patient's first admission to hospital with respiratory complications (14/38, 37%) and when symptoms of SDB are present (14/38, 37%). Half of the CPNG members request initial Respirology consultation at the time of DMD diagnosis. Both groups request routine pulmonary function tests. Ninety-six percent of respirologists use maximal inspiratory (MIP) and expiratory pressures (MEP) to assess respiratory muscle strength, whereas 82% of CPNG members additionally use peak cough flow. Assessment for SDB is requested by both groups when pulmonary function is abnormal or patients are symptomatic. Respirologists favor polysomnography, whereas CPNG members use overnight pulse oximetry. Nocturnal non-invasive ventilation and lung volume recruitment (LVR) are used in a minority of patients. Respirologists and CPNG members provide similar respiratory management of DMD patients, but differ in timing of consultation and choice of tests for pulmonary function and SDB. Canadian practices differ from the American Thoracic Society and Centre for Disease Control guidelines.

Respiration-Correlated Image Guidance Is the Most Important Radiotherapy Motion Management Strategy for Most Lung Cancer Patients

The purpose of this study was to quantify the effects of four-dimensional computed tomography (4DCT), 4D image guidance (4D-IG), and beam gating on calculated treatment field margins in a lung cancer patient population. Images were acquired from 46 lung cancer patients participating in four separate protocols at three institutions in Europe and the United States. Seven patients were imaged using fluoroscopy, and 39 patients were imaged using 4DCT. The magnitude of respiratory tumor motion was measured. The required treatment field margins were calculated using a statistical recipe (van Herk M, et al. Int J Radiat Oncol Biol Phys 2000;474:1121-1135), with magnitudes of all uncertainties, except respiratory peak-to-peak displacement, the same for all patients, taken from literature. Required margins for respiratory motion management were calculated using the residual respiratory tumor motion for each patient for various motion management strategies. Margin reductions for respiration management were calculated using 4DCT, 4D-IG, and gated beam delivery. The median tumor motion magnitude was 4.4 mm for the 46 patients (range 0-29.3 mm). This value corresponded to required treatment field margins of 13.7 to 36.3 mm (median 14.4 mm). The use of 4DCT, 4D-IG, and beam gating required margins that were reduced by 0 to 13.9 mm (median 0.5 mm), 3 to 5.2 mm (median 5.1 mm), and 0 to 7 mm (median 0.2 mm), respectively, to a total of 8.5 to 12.4 mm (median 8.6 mm). A respiratory management strategy for lung cancer radiotherapy including planning on 4DCT scans and daily image guidance provides a potential reduction of 37% to 47% in treatment field margins. The 4D image guidance strategy was the most effective strategy for >85% of the patients.

Canadian survey of pediatric respiratory management strategies for Duchenne muscular dystrophy

Canadian survey of pediatric respiratory management strategies for Duchenne muscular dystrophy

Permissive hypercapnia practices among neonatologists in the United States: Results of a national survey

Objective: There is no consensus among practicing neonatologists regarding the definition of permissive hypercapnia and yet its practice is commonly employed to prevent lung injury from excessive ventilation. The goal of this study was to determine clinical practice among neonatologists regarding a definition of permissive hypercapnia in a preterm infant based upon gestational age at birth, degree of respiratory support, and acute vs. chronic management. Methods: Surveys were e-mailed to neonatologists who are members of the AAP Section on Perinatal Pediatrics containing a link to an on-line survey company (www.surveymonkey.com). Responses were compared using Pearson X 2 analyses. Results: Of 2689 individuals surveyed, 747 (28%) completed the survey. 97% of those respondents reported practicing permissive hypercapnia. Regardless of stated permissive hypercapnia practice preferences, the majority of neonatologists accept 45-55 mm Hg as their target PaCO2 levels on the first day of life and 55-65 mm Hg thereafter. Conclusions: Our data suggest most neonatologists surveyed employ a permissive hypercapnia respiratory management strategy, as they accept higher than normal PaCO2 levels for preterm infants . Our findings highlight the need for continuing studies to document whether the values of targeted PaCO2 reported here provide lung protection without compromising overall safety and long-term complications.

Early Nasal Continuous Positive Airway Pressure and Necrotizing Enterocolitis in Preterm Infants

The use of early nasal continuous positive airway pressure (ENCPAP) as the mode of initial respiratory support for very low birth weight (VLBW) infants has been increasing. The impact of CPAP and oxygen on gut mucosa and perfusion in premature infants is not known. The relation between ENCPAP and necrotizing enterocolitis (NEC) has not been adequately addressed. To evaluate if the use of an individualized respiratory management strategy encouraging the use of ENCPAP is associated with an increased risk of NEC, and to determine risk factors for NEC in premature infants supported by CPAP. A retrospective analysis was conducted on VLBW infants (birth weight < 1500 g) managed at 2 institutions that use an ENCPAP respiratory management strategy for premature infants. Data on the use of oxygen and mode of ventilatory support were collected during the first 3 days of life. Diagnosis of NEC was used as the dependent variable in a logistic regression model. Birth weight, gender, prenatal steroid use, mode of respiratory support (CPAP versus ventilator) and fraction of inspired oxygen, umbilical artery catheter placement, partial pressure of oxygen, patent ductus arteriosus, early sepsis, hospital, and delivery room management (ENCPAP versus initial intubation) were controlled for in the model. Data on 343 premature infants were collected for this study. Mean birth weight was 999 +/- 289 g and gestational age was 28 +/- 2.6 weeks. The majority of patients were managed with ENCPAP, with only 13% of patients intubated in the delivery room. The overall incidence of NEC was 7% (n = 24). The exposure to ENCPAP did not increase the risk for NEC compared with the use of a ventilator. CONCLUSIONS. The risk of NEC in VLBW premature infants was not increased by the use of ENCPAP. Initial respiratory support with ENCPAP seems to be a safe alternative to routine intubation and mechanical ventilation in premature infants.

Strategies for preventing bronchopulmonary dysplasia

Neonatologists and pulmonary biologists have long sought preventive treatments for bronchopulmonary dysplasia (BPD). The purpose of this review is to highlight recent reports of a number of potential treatments intended to prevent BPD and to discuss the controversies surrounding preventive strategies. The evolution of BPD from a disorder of pulmonary injury affecting moderately preterm infants, to one characterized by a developmental pulmonary arrest among survivors of extreme prematurity has important implications for BPD prevention. Recent recognition that the pathogenesis of BPD might have prenatal origins raises new challenges and opportunities for studies of BPD prevention; however, most current preventive strategies for BPD focus on respiratory management. Neither past nor current clinical trials have shown a conclusive benefit of a single preventive treatment strategy. Promising but still largely unproven preventive respiratory treatments include: high frequency oscillatory ventilation, permissive hypercapnea, and inhaled nitric oxide. Observational and recent laboratory data support the need for randomized clinical trials of continuous positive airway pressure versus mechanical ventilation. Additionally, clinical trials are needed to address the deficit in our knowledge of the potential benefits and risks of postnatal low dose corticosteroid treatment. Further study of superoxide dismutase, inositol, and alpha-1 proteinase inhibitor also are warranted on the basis of recent clinical trials or meta-analyses. Only Vitamin A has proven a safe and effective preventive treatment for BPD. Additional studies of respiratory technologies, management strategies, and protective molecules are needed. Directed cytokine and genetic therapies are on the horizon.