Implementing a Family-Centered Rounds Intervention Using Novel Mentor-Trios.

BACKGROUND AND OBJECTIVES: Patient and Family Centered I-PASS (PFC I-PASS) emphasizes family and nurse engagement, health literacy, and structured communication on family-centered rounds organized around the I-PASS framework (Illness severity-Patient summary-Action items-Situational awareness-Synthesis by receiver). We assessed adherence, safety, and experience after implementing PFC I-PASS using a novel "Mentor-Trio" implementation approach with multidisciplinary parent-nurse-physician teams coaching sites. METHODS: Hybrid Type II effectiveness-implementation study from 2/29/19-3/13/22 with ≥3 months of baseline and 12 months of postimplementation data collection/site across 21 US community and tertiary pediatric teaching hospitals. We conducted rounds observations and surveyed nurses, physicians, and Arabic/Chinese/English/Spanish-speaking patients/parents. RESULTS: We conducted 4557 rounds observations and received 2285 patient/family, 1240 resident, 819 nurse, and 378 attending surveys. Adherence to all I-PASS components, bedside rounding, written rounds summaries, family and nurse engagement, and plain language improved post-implementation (13.0%-60.8% absolute increase by item), all P < .05. Except for written summary, improvements sustained 12 months post-implementation. Resident-reported harms/1000-resident-days were unchanged overall but decreased in larger hospitals (116.9 to 86.3 to 72.3 pre versus early- versus late-implementation, P = .006), hospitals with greater nurse engagement on rounds (110.6 to 73.3 to 65.3, P < .001), and greater adherence to I-PASS structure (95.3 to 73.6 to 72.3, P < .05). Twelve of 12 measures of staff safety climate improved (eg, "excellent"/"very good" safety grade improved from 80.4% to 86.3% to 88.0%), all P < .05. Patient/family experience and teaching were unchanged. CONCLUSIONS: Hospitals successfully used Mentor-Trios to implement PFC I-PASS. Family/nurse engagement, safety climate, and harms improved in larger hospitals and hospitals with better nurse engagement and intervention adherence. Patient/family experience and teaching were not affected.

Effect of Patient and Family Centered I-PASS on adverse event rates in hospitalized children with complex chronic conditions.

BACKGROUND: Children with complex chronic conditions (CCCs) are at risk for adverse events (AEs) during hospitalizations. OBJECTIVE: We compared the effect of Patient and Family Centered (PFC)I-PASS on AE rates in children with and without CCCs. DESIGNS, SETTINGS, AND PARTICIPANTS: Patients were drawn from the PFCI-PASS study, which included 3106 hospitalized children from seven North American pediatric hospitals between December 2014 and January 2017. MAIN OUTCOME AND MEASURES: An effect modification analysis did not show difference in the intervention on children with and without CCCs (RRR 0.81, 95% CI [0.59-1.10]; p = .2). RESULTS: In multivariable analysis, the adjusted incidence rate ratiofor AEs in children with CCCs was 0.5 (95% CI = 0.3-0.9, p = .01) with PFC I-PASS exposure; there was no statistically significant change in AEs for children without CCCs [IRR 0.6 (95% CI = 0.3-1.2; p = .1)].

Implementation of the I-PASS handoff program in diverse clinical environments: A multicenter prospective effectiveness implementation study.

BACKGROUND: Handoff miscommunications are a leading source of medical errors. Harmful medical errors decreased in pediatric academic hospitals following implementation of the I-PASS handoff improvement program. However, implementation across specialties has not been assessed. OBJECTIVE: To determine if I-PASS implementation across diverse settings would be associated with improvements in patient safety and communication. DESIGN: Prospective Type 2 Hybrid effectiveness implementation study. SETTINGS AND PARTICIPANTS: Residents from diverse specialties across 32 hospitals (12 community, 20 academic). INTERVENTION: External teams provided longitudinal coaching over 18 months to facilitate implementation of an enhanced I-PASS program and monthly metric reviews. MAIN OUTCOME AND MEASURES: Systematic surveillance surveys assessed rates of resident-reported adverse events. Validated direct observation tools measured verbal and written handoff quality. RESULTS: 2735 resident physicians and 760 faculty champions from multiple specialties (16 internal medicine, 13 pediatric, 3 other) participated. 1942 error surveillance reports were collected. Major and minor handoff-related reported adverse events decreased 47% following implementation, from 1.7 to 0.9 major events/person-year (p < .05) and 17.5 to 9.3 minor events/person-year (p < .001). Implementation was associated with increased inclusion of all five key handoff data elements in verbal (20% vs. 66%, p < .001, n = 4812) and written (10% vs. 74%, p < .001, n = 1787) handoffs, as well as increased frequency of handoffs with high quality verbal (39% vs. 81% p < .001) and written (29% vs. 78%, p < .001) patient summaries, verbal (29% vs. 78%, p < .001) and written (24% vs. 73%, p < .001) contingency plans, and verbal receiver syntheses (31% vs. 83%, p < .001). Improvement was similar across provider types (adult vs. pediatric) and settings (community vs. academic).

Patient and Family-Centered I-PASS SCORE Program: Resident and Advanced Care Provider Training Materials.

Introduction: Patient and family-centered rounds (PFCRs) are an important element of family-centered care often used in the inpatient pediatric setting. However, techniques and best practices vary, and faculty, trainees, nurses, and advanced care providers may not receive formal education in strategies that specifically enhance communication on PFCRs. Methods: Harnessing the use of structured communication, we developed the Patient and Family-Centered I-PASS Safer Communication on Rounds Every Time (SCORE) Program. The program uses a standardized framework for rounds communication via the I-PASS mnemonic, principles of health literacy, and techniques for patient/family engagement and bidirectional communication. The resident and advanced care provider training materials, a component of the larger SCORE Program, incorporate a flipped classroom approach as well as interactive exercises, simulations, and virtual learning options to optimize learning and retention via a 90-minute workshop. Results: Two hundred forty-six residents completed the training and were evaluated on their knowledge and confidence regarding key elements of the curriculum. Eighty-eight percent of residents agreed/strongly agreed that after training they could activate and engage families and all members of the interprofessional team to create a shared mental model; 90% agreed/strongly agreed that they could discuss the roles/responsibilities of various team members during PFCRs. Discussion: The Patient and Family-Centered I-PASS SCORE Program provides a structured framework for teaching advanced communication techniques that can improve provider knowledge of and confidence with engaging and communicating with patients/families and other members of the interprofessional team during PFCRs.

Twelve Tips for Teaching with Virtual Learning Platforms.

This article was migrated. The article was marked as recommended. Met with the challenge of physical distancing during the escalation of the COVID-19 pandemic, medical educators rapidly pivoted their educational repertoires to virtual learning platforms. While selection and utilization of virtual platforms may vary amongst medical educators, elements of evidence-based educational theories, collaborative learning, and learner engagement are essential to the success of learning for any format. In this piece we outline 12 tips for virtual learning, drawing on concepts from available literature and our collective experience as medical educators. As virtual learning platforms continue to evolve, medical educators should leverage different modalities, without compromising the fundamental elements and theories that promote learner success.

Evidence-Based Medicine in the Clinical Learning Environment of Pediatric Hospital Medicine.

The article begins with an overview of evidence-based medicine (EBM), including its history and core principles. Next, the article discusses how the current clinical learning environment has shaped EBM, including the accessibility and portability of technology; the access to electronic search engines and libraries; and the movement toward applying the best evidence through order sets, clinical guidelines, and pathways to work toward standardizing care. The article ends with a focus on how educators can influence a trainee's knowledge, skills, attitudes, and behaviors regarding EBM.

Patient safety after implementation of a coproduced family centered communication programme: multicenter before and after intervention study

OBJECTIVE: To determine whether medical errors, family experience, and communication processes improved after implementation of an intervention to standardize the structure of healthcare provider-family communication on family centered rounds. DESIGN: Prospective, multicenter before and after intervention study. SETTING: Pediatric inpatient units in seven North American hospitals, 17 December 2014 to 3 January 2017. PARTICIPANTS: All patients admitted to study units (3106 admissions, 13171 patient days); 2148 parents or caregivers, 435 nurses, 203 medical students, and 586 residents. INTERVENTION: Families, nurses, and physicians coproduced an intervention to standardize healthcare provider-family communication on ward rounds ("family centered rounds"), which included structured, high reliability communication on bedside rounds emphasizing health literacy, family engagement, and bidirectional communication; structured, written real-time summaries of rounds; a formal training programme for healthcare providers; and strategies to support teamwork, implementation, and process improvement. MAIN OUTCOME MEASURES: Medical errors (primary outcome), including harmful errors (preventable adverse events) and non-harmful errors, modeled using Poisson regression and generalized estimating equations clustered by site; family experience; and communication processes (eg, family engagement on rounds). Errors were measured via an established systematic surveillance methodology including family safety reporting. RESULTS: The overall rate of medical errors (per 1000 patient days) was unchanged (41.2 (95% confidence interval 31.2 to 54.5) pre-intervention v 35.8 (26.9 to 47.7) post-intervention, P=0.21), but harmful errors (preventable adverse events) decreased by 37.9% (20.7 (15.3 to 28.1) v 12.9 (8.9 to 18.6), P=0.01) post-intervention. Non-preventable adverse events also decreased (12.6 (8.9 to 17.9) v 5.2 (3.1 to 8.8), P=0.003). Top box (eg, "excellent") ratings for six of 25 components of family reported experience improved; none worsened. Family centered rounds occurred more frequently (72.2% (53.5% to 85.4%) v 82.8% (64.9% to 92.6%), P=0.02). Family engagement 55.6% (32.9% to 76.2%) v 66.7% (43.0% to 84.1%), P=0.04) and nurse engagement (20.4% (7.0% to 46.6%) v 35.5% (17.0% to 59.6%), P=0.03) on rounds improved. Families expressing concerns at the start of rounds (18.2% (5.6% to 45.3%) v 37.7% (17.6% to 63.3%), P=0.03) and reading back plans (4.7% (0.7% to 25.2%) v 26.5% (12.7% to 7.3%), P=0.02) increased. Trainee teaching and the duration of rounds did not change significantly. CONCLUSIONS: Although overall errors were unchanged, harmful medical errors decreased and family experience and communication processes improved after implementation of a structured communication intervention for family centered rounds coproduced by families, nurses, and physicians. Family centered care processes may improve safety and quality of care without negatively impacting teaching or duration of rounds. TRIAL REGISTRATION: ClinicalTrials.gov NCT02320175.

Families as Partners in Hospital Error and Adverse Event Surveillance.

Importance: Medical errors and adverse events (AEs) are common among hospitalized children. While clinician reports are the foundation of operational hospital safety surveillance and a key component of multifaceted research surveillance, patient and family reports are not routinely gathered. We hypothesized that a novel family-reporting mechanism would improve incident detection. Objective: To compare error and AE rates (1) gathered systematically with vs without family reporting, (2) reported by families vs clinicians, and (3) reported by families vs hospital incident reports. Design, Setting, and Participants: We conducted a prospective cohort study including the parents/caregivers of 989 hospitalized patients 17 years and younger (total 3902 patient-days) and their clinicians from December 2014 to July 2015 in 4 US pediatric centers. Clinician abstractors identified potential errors and AEs by reviewing medical records, hospital incident reports, and clinician reports as well as weekly and discharge Family Safety Interviews (FSIs). Two physicians reviewed and independently categorized all incidents, rating severity and preventability (agreement, 68%-90%; κ, 0.50-0.68). Discordant categorizations were reconciled. Rates were generated using Poisson regression estimated via generalized estimating equations to account for repeated measures on the same patient. Main Outcomes and Measures: Error and AE rates. Results: Overall, 746 parents/caregivers consented for the study. Of these, 717 completed FSIs. Their median (interquartile range) age was 32.5 (26-40) years; 380 (53.0%) were nonwhite, 566 (78.9%) were female, 603 (84.1%) were English speaking, and 380 (53.0%) had attended college. Of 717 parents/caregivers completing FSIs, 185 (25.8%) reported a total of 255 incidents, which were classified as 132 safety concerns (51.8%), 102 nonsafety-related quality concerns (40.0%), and 21 other concerns (8.2%). These included 22 preventable AEs (8.6%), 17 nonharmful medical errors (6.7%), and 11 nonpreventable AEs (4.3%) on the study unit. In total, 179 errors and 113 AEs were identified from all sources. Family reports included 8 otherwise unidentified AEs, including 7 preventable AEs. Error rates with family reporting (45.9 per 1000 patient-days) were 1.2-fold (95% CI, 1.1-1.2) higher than rates without family reporting (39.7 per 1000 patient-days). Adverse event rates with family reporting (28.7 per 1000 patient-days) were 1.1-fold (95% CI, 1.0-1.2; P = .006) higher than rates without (26.1 per 1000 patient-days). Families and clinicians reported similar rates of errors (10.0 vs 12.8 per 1000 patient-days; relative rate, 0.8; 95% CI, .5-1.2) and AEs (8.5 vs 6.2 per 1000 patient-days; relative rate, 1.4; 95% CI, 0.8-2.2). Family-reported error rates were 5.0-fold (95% CI, 1.9-13.0) higher and AE rates 2.9-fold (95% CI, 1.2-6.7) higher than hospital incident report rates. Conclusions and Relevance: Families provide unique information about hospital safety and should be included in hospital safety surveillance in order to facilitate better design and assessment of interventions to improve safety.

EEG slow waves in traumatic brain injury: Convergent findings in mouse and man.

OBJECTIVE: Evidence from previous studies suggests that greater sleep pressure, in the form of EEG-based slow waves, accumulates in specific brain regions that are more active during prior waking experience. We sought to quantify the number and coherence of EEG slow waves in subjects with mild traumatic brain injury (mTBI). METHODS: We developed a method to automatically detect individual slow waves in each EEG channel, and validated this method using simulated EEG data. We then used this method to quantify EEG-based slow waves during sleep and wake states in both mouse and human subjects with mTBI. A modified coherence index that accounts for information from multiple channels was calculated as a measure of slow wave synchrony. RESULTS: Brain-injured mice showed significantly higher theta:alpha amplitude ratios and significantly more slow waves during spontaneous wakefulness and during prolonged sleep deprivation, compared to sham-injured control mice. Human subjects with mTBI showed significantly higher theta:beta amplitude ratios and significantly more EEG slow waves while awake compared to age-matched control subjects. We then quantified the global coherence index of slow waves across several EEG channels in human subjects. Individuals with mTBI showed significantly less EEG global coherence compared to control subjects while awake, but not during sleep. EEG global coherence was significantly correlated with severity of post-concussive symptoms (as assessed by the Neurobehavioral Symptom Inventory scale). CONCLUSION AND IMPLICATIONS: Taken together, our data from both mouse and human studies suggest that EEG slow wave quantity and the global coherence index of slow waves may represent a sensitive marker for the diagnosis and prognosis of mTBI and post-concussive symptoms.

EEG slow waves in traumatic brain injury: Convergent findings in mouse and man.

OBJECTIVE: Evidence from previous studies suggests that greater sleep pressure, in the form of EEG-based slow waves, accumulates in specific brain regions that are more active during prior waking experience. We sought to quantify the number and coherence of EEG slow waves in subjects with mild traumatic brain injury (mTBI). METHODS: We developed a method to automatically detect individual slow waves in each EEG channel, and validated this method using simulated EEG data. We then used this method to quantify EEG-based slow waves during sleep and wake states in both mouse and human subjects with mTBI. A modified coherence index that accounts for information from multiple channels was calculated as a measure of slow wave synchrony. RESULTS: Brain-injured mice showed significantly higher theta:alpha amplitude ratios and significantly more slow waves during spontaneous wakefulness and during prolonged sleep deprivation, compared to sham-injured control mice. Human subjects with mTBI showed significantly higher theta:beta amplitude ratios and significantly more EEG slow waves while awake compared to age-matched control subjects. We then quantified the global coherence index of slow waves across several EEG channels in human subjects. Individuals with mTBI showed significantly less EEG global coherence compared to control subjects while awake, but not during sleep. EEG global coherence was significantly correlated with severity of post-concussive symptoms (as assessed by the Neurobehavioral Symptom Inventory scale). CONCLUSION AND IMPLICATIONS: Taken together, our data from both mouse and human studies suggest that EEG slow wave quantity and the global coherence index of slow waves may represent a sensitive marker for the diagnosis and prognosis of mTBI and post-concussive symptoms.

Low-temperature dynamic nuclear polarization of gases in Frozen mixtures.

PURPOSE: To present a new cryogenic technique for preparing gaseous compounds in solid mixtures for polarization using dynamic nuclear polarization (DNP). METHODS: (129) Xe and (15) N2 O samples were prepared using the presented method. Samples were hyperpolarized at 1.42K at 5 Tesla. (129) Xe was polarized at 1.65K and 1.42K to compare enhancement. Polarization levels for both samples and T1 relaxation times for the (129) Xe sample were measured. Sample pulverization for the (129) Xe and controlled annealing for both samples were introduced as additional steps in sample preparation. RESULTS: Enhancement increased by 15% due to a temperature drop from 1.65K to 1.42K for the (129) Xe sample. A polarization level of 20 ± 3% for the (129) Xe sample was achieved, a two-fold increase from 10 ± 1% after pulverization of the sample at 1.42K. T1 of the (129) Xe sample was increased by more than three-fold by means of annealing. In the case of (15) N2 O, annealing led to a ∼two-fold increase in the signal level after DNP. CONCLUSION: The presented technique for producing and manipulating solid gas/glassing agent/radical mixtures for DNP led to high polarization levels in (129) Xe and (15) N2 O samples. These methods show potential for polarizing other gases using DNP technology. Magn Reson Med 76:1007-1014, 2016. © 2015 Wiley Periodicals, Inc.

Versatile pulse sequence device to conserve hyperpolarization for NMR and MRI studies.

PURPOSE: Levitt and co-workers have described the M2S pulse sequence which transfers between longitudinal and singlet spin order. Building on this work, we describe the construction of a portable M2S pulse sequence generator to increase the relaxation time of polarized compounds. Additionally, we investigate the efficiency of spin order transfer under conditions where physical parameters of the system are not known precisely. THEORY AND METHODS: A portable M2S generator is built. Longitudinally polarized N2O is converted to the singlet state by both adiabatic transfer and by the M2S sequence. Density matrix simulations are used to model the effects of mismatched chemical shift, flip angle, and scalar couplings. RESULTS: Density matrix simulations suggest that to convert 95% of the longitudinal m = 1 triplet state population to the singlet order we must match the Larmor precession frequency to the excitation radiofrequency field by 10%, the scalar couplings must be determined to better than 0.6%, and the flip angle must be calibrated to better than 2%. CONCLUSION: The sequence is robust against many mismatched physical parameters of the species we are converting. Additionally, the instrument's portability allows for the conversion of hyperpolarized species near a polarizer. The lifetime is increased by ∼12-fold. This is highly advantageous in systems where the hyperpolarized media relax rapidly.

Dietary therapy mitigates persistent wake deficits caused by mild traumatic brain injury.

Sleep disorders are highly prevalent in patients with traumatic brain injury (TBI) and can significantly impair cognitive rehabilitation. No proven therapies exist to mitigate the neurocognitive consequences of TBI. We show that mild brain injury in mice causes a persistent inability to maintain wakefulness and decreases orexin neuron activation during wakefulness. We gave mice a dietary supplement of branched-chain amino acids (BCAAs), precursors for de novo glutamate synthesis in the brain. BCAA therapy reinstated activation of orexin neurons and improved wake deficits in mice with mild brain injury. Our data suggest that dietary BCAA intervention, acting in part through orexin, can ameliorate injury-induced sleep disturbances and may facilitate cognitive rehabilitation after brain injury.

Positive end-expiratory pressure increments during anesthesia in normal lung result in hysteresis and greater numbers of smaller aerated airspaces.

BACKGROUND: Although it is recognized that pulmonary hysteresis can influence the effects of positive end-expiratory pressure (PEEP), the extent to which expansion of previously opened (vs. newly opening) peripheral airspaces contribute to increased lung volume is unknown. METHODS: Following a recruitment maneuver, rats were ventilated with constant tidal volumes and imaged during ascending and descending ramps of PEEP. RESULTS: The authors estimated peripheral airspace dimensions by measuring the apparent diffusion coefficient of He in 10 rats. In a separate group (n = 5) undergoing a similar protocol, the authors used computerized tomography to quantify lung volume. Hysteresis was confirmed by larger end-inspiratory lung volume (mean ± SD; all PEEP levels included): 8.4 ± 2.8 versus 6.8 ± 2.0 ml (P < 0.001) and dynamic compliance: 0.52 ± 0.12 versus 0.42 ± 0.09 ml/cm H2O (P < 0.001) during descending versus ascending PEEP ramps. Apparent diffusion coefficient increased with PEEP, but it was smaller during the descending versus ascending ramps for corresponding levels of PEEP: 0.168 ± 0.019 versus 0.183 ± 0.019 cm/s (P < 0.001). Apparent diffusion coefficient was smaller in the posterior versus anterior lung regions, but the effect of PEEP and hysteresis on apparent diffusion coefficient was greater in the posterior regions. CONCLUSIONS: The authors' study results suggest that in healthy lungs, larger lung volumes due to hysteresis are associated with smaller individual airspaces. This may be explained by opening of previously nonaerated peripheral airspaces rather than expansion of those already aerated. Setting PEEP on a descending ramp may minimize distension of individual airspaces.

A variability study of regional alveolar oxygen tension measurement in humans using hyperpolarized (3) He MRI.

PURPOSE: A systematic study of the short-term and long-term variability of regional alveolar partial pressure of oxygen tension (pA O2 ) measurements using (3) He magnetic resonance imaging was presented. Additionally, the repeatability of the average evaluated pA O2 was compared with that of the standard pulmonary function tests. METHODS: Pulmonary function test and pA O2 imaging were performed on 4 nonsmokers (1 M, 3 F, 56 ± 1.7 years) and 4 smokers (3 M, 1 F, 52 ± 7.5 years) during three visits over the course of 2 weeks. Two measurements were performed per visit. Variability of pA O2 was assessed using a mixed-effect model, with an intraclass correlation coefficient calculated for each group. The coefficient of variation of pA O2 over the 3-day period was also compared with the coefficient of variation of pulmonary function test results. RESULTS: Short-term regional variability based on intraclass correlation coefficient was 0.71 for nonsmokers, and 0.63 for smokers, with long-term variability significantly lower at 0.59 and 0.47, respectively. While the coefficient of variation of the average pA O2 was similar to the repeatability of the diffusing capacity of CO, it was significantly higher than that of Forced Vital Capacity (P = 0.02). CONCLUSION: Short-term and long-term pA O2 variability differences were used as an indication of true physiological changes in order to measure technical reproducibility. Smokers show higher physiologic variability and less technical reproducibility. The suggested pA O2 -imaging technique showed a reasonable regional repeatability in nonsmokers as well as the ability to detect differences between the two groups with similar reproducibility and superior discriminatory ability when compared with pulmonary function tests.

Imaging the interaction of atelectasis and overdistension in surfactant-depleted lungs.

OBJECTIVE: Atelectasis and surfactant depletion may contribute to greater distension-and thereby injury-of aerated lung regions; recruitment of atelectatic lung may protect these regions by attenuating such overdistension. However, the effects of atelectasis (and recruitment) on aerated airspaces remain elusive. We tested the hypothesis that during mechanical ventilation, surfactant depletion increases the dimensions of aerated airspaces and that lung recruitment reverses these changes. DESIGN: Prospective imaging study in an animal model. SETTING: Research imaging facility. SUBJECTS: Twenty-seven healthy Sprague Dawley rats. INTERVENTIONS: Surfactant depletion was obtained by saline lavage in anesthetized, ventilated rats. Alveolar recruitment was accomplished using positive end-expiratory pressure and exogenous surfactant administration. MEASUREMENTS AND MAIN RESULTS: Airspace dimensions were estimated by measuring the apparent diffusion coefficient of He, using diffusion-weighted hyperpolarized gas magnetic resonance imaging. Atelectasis was demonstrated using computerized tomography and by measuring oxygenation. Saline lavage increased atelectasis (increase in nonaerated tissue from 1.2% to 13.8% of imaged area, p < 0.001), and produced a concomitant increase in mean apparent diffusion coefficient (~33%, p < 0.001) vs. baseline; the heterogeneity of the computerized tomography signal and the variance of apparent diffusion coefficient were also increased. Application of positive end-expiratory pressure and surfactant reduced the mean apparent diffusion coefficient (~23%, p < 0.001), and its variance, in parallel to alveolar recruitment (i.e., less computerized tomography densities and heterogeneity, increased oxygenation). CONCLUSIONS: Overdistension of aerated lung occurs during atelectasis is detectable using clinically relevant magnetic resonance imaging technology, and could be a key factor in the generation of lung injury during mechanical ventilation. Lung recruitment by higher positive end-expiratory pressure and surfactant administration reduces airspace distension.

Determination of the singlet state lifetime of dissolved nitrous oxide from high field relaxation measurements.

Longitudinal spin relaxation due to modulation of dipolar interactions often limits the development of hyperpolarized magnetic tracers. Recently, it has been demonstrated that transferring spin order to a singlet state significantly increases the polarization lifetimes in systems where nitrous oxide is dissolved in a liquid solvent. Additionally, previous studies have suggested that the longitudinal relaxation of nitrous oxide is largely dominated by the spin-rotation interaction. Models of spin-relaxation under Brownian motion naïvely predict the angular momentum reorienting correlation time of the spin rotation interaction to be inversely proportional to the viscosity of the solution. This dependence implies the singlet lifetime can be lengthened by increasing the dissolving solvent's viscosity-an extension which is not observed. Our work formulates a model which describes the relaxation of nitrous oxide dissolved in various solvents. We investigate the effect of altering the temperature of the solvent, as well as the effect of varying solute-solvent interactions on the singlet state as well as the longitudinal polarization lifetime. We predict the singlet lifetime for nitrous oxide dissolved in several solvents by fitting rotational and angular momentum correlation times measured at high magnetic field, and relate singlet relaxation to translational diffusion constants.