Supplemental O2 Research Articles

Pulmonary hypertension is present in a rodent model of bronchopulmonary dysplasia at 21 days but not 6 months of age (715.1)

In preterm infants, mechanical ventilation with supplemental O2 can cause bronchopulmonary dysplasia (BPD), characterized by dysmorphic pulmonary vasculature and simplified alveoli. Although vascular cross‐sectional area is diminished, contributing to right ventricular hypertension (RVH), it is unknown whether this improves with age. We hypothesized that RVH would continue into adulthood in a rat model of BPD. Rats were exposed to 21% or 95% O2 from birth to postnatal day 8. At 21 days or 6 months of age, a fluid‐filled catheter was placed in the RV to measure RV pressure and inject 2x108 4μm fluorescent spheres. At the conclusion of the experiment, lungs were harvested, air dried, and imaged using laser scanning confocal microscopy to investigate capillary density. At 21 days, rats exposed to 95% O2 demonstrated RVH (31±5 mmHg), which was absent in both 21 day controls (16±2 mmHg, p=0.028) and 6 month old rats exposed to 95% O2 (20±10 mmHg, p=0.014). Interestingly, the density and distribution of spheres was not different between 6 month old rats exposed to 95% or 21%, suggesting that the normalization of right heart pressure by 6 months is the result of improved alveolar capillary density. Our findings indicate that children and infants with BPD may be at high risk for RVH, but that this resolves with age.Grant Funding Source: Supported by NIH 5R01HL115061

Enhanced SpO2 in Response to Intermittent Normobaric Hypoxia in a Patient (Case Study) with COPD (LB787)

Recent studies by Cardoso et al (The FASEB Journal, April 9, 2013; v27, 938.7) using hypoxic pre‐conditioning (HP) add support to its value in the management of T2D, CV and pulmonary disease. We now report enhancement of SpO2 levels (P<0.0001) for a 75 yr old patient with Stage IV COPD when we intermittently employed a set of pre and post conditioning 1 hr interruption (at rest with SpO2 recorded at 1 min intervals) of her 24/7 nasal oxygen flow from Mar 2012 through Dec 2013 (interventions were repeated at 1‐3 month intervals at the patient’s discretion). Normalization of SpO2 was recorded when in late Dec 2013 we added bicycling at 6 mph (off supplemental O2 during exercise) 24 hrs after our 1 hr hypoxic interventions. Mean SpO2 on Dec 30, 2013 = 87.1±3.4 and Jan 6, 9, 14 and 18, 2014 = 91.9±2.3; 95.1± 1.71; 95.7±1.1; 87.9±3.6, respectively (Dec 2013 vs Jan 2014, P<0.0001). All observations were re‐confirmed Feb 14, 2014. The results suggest patients with COPD respond to HP with improved quality of life, and increased tolerance to exercise that may lead, as in our patient, to significantly lower frequency of prescribed medication.Grant Funding Source: San Pedro Univ. Peru; Federal Univ. COPPE, RJ, Brazil, Private donations

ECG Response: March 25, 2014

ECG Challenge: A 72-year-old man with a history of chronic obstructive pulmonary disease presents with an increase in shortness of breath that began 2 weeks ago after experiencing an upper respiratory infection presenting with a cough productive of yellowish sputum, pleuritic chest pain, and a low grade fever with temperatures of up to 100°. He did not seek medical attention, but because of worsening shortness of breath he presented to the emergency room. On physical examination he has bilateral rhonchous sounds and wheezing. A chest x-ray showed evidence of chronic obstructive pulmonary disease with hyperaeration and fibrous streaking. His O2 saturation was 88% on room air. He was placed on supplemental O2 via a nasal cannula at 4 L/min. He received albuterol therapy via a nebulizer. Shortly after his first treatment he was noted to have a transient increase in heart rate and an ECG was obtained. The first 4 QRS complexes have a …

Need for Supplemental Oxygen at Discharge in Infants with Bronchopulmonary Dysplasia Is Not Associated with Worse Neurodevelopmental Outcomes at 3 Years Corrected Age

ObjectivesTo determine if chronic oxygen dependency (discharge home on supplemental oxygen) in children with bronchopulmonary dysplasia (BPD; defined as requirement for supplemental O2 at 36 weeks postmenstrual age) predicts neurodevelopmental disability rates and growth outcomes at 36 months corrected age (CA).Study DesignLongitudinal cohort study.SettingSouthern Alberta regional center located at high altitude.ParticipantsPreterm infants weighing ≤1250 grams with no BPD, BPD, and BPD with chronic oxygen dependency.Main outcome measuresNeurodevelopmental and growth outcomes.ResultsOf 1563 preterm infants admitted from 1995–2007, 1212 survived. Complete follow-up data were available for 1030 (85%) children. Children in BPD and BPD with chronic oxygen dependency groups had significantly lower birth weights, gestational ages, prolonged mechanical ventilation and oxygen supplementation and received more postnatal steroids, compared to those without BPD. Children with BPD and BPD with chronic oxygen dependency were more likely to be below the 5th centile in weight and height compared to those without BPD but there was little difference between the BPD and BPD with chronic oxygen dependency groups. After controlling for confounding variables, children who had BPD and BPD with chronic oxygen dependency had higher odds of neurodevelopmental disability compared to those without BPD [OR (odds ratio) 1.9 (95%CI 1.1 to 3.5) and OR 1.8 (1.1 to 2.9), respectively], with no significant difference between BPD and BPD with chronic oxygen dependency [OR 0.9 (95% CI 0.6 to 1.5)].ConclusionsBPD and BPD with chronic oxygen dependency in children predicts abnormal neurodevelopmental outcomes at 36 months CA. However, the neurodevelopmental disability rates were not significantly higher in BPD with chronic oxygen dependency children compared to children with BPD only. Compared to those without BPD, growth is impaired in children with BPD and BPD with chronic oxygen dependency, but no difference between the latter two groups.

Bronchiolitis obliterans with allogeneic hematopoietic cell transplantation: a 10-year experience of the Okayama BMT Group

Bronchiolitis obliterans (BO) is a devastating complication of allogeneic hematopoietic stem cell transplantation (HSCT). We retrospectively studied 465 patients who underwent HSCT in the Okayama BMT Group between 2000 and 2009, and describe the detailed clinical features of 13 patients with BO. The 5-year cumulative incidence of BO was 3.43 %. The median time from transplantation to onset of BO was 15 months. In seven of the 13 patients, the primary symptom was only cough, indicating that cough was an important initial symptom for early diagnosis. The median duration from the onset of BO to the requirement of O2 supplementation was 13 months and the main cause of death was respiratory failure. History of chronic graft-versus-host disease was a significant risk factor. Furthermore, female recipients were at greater risk of BO than male recipients; however, no other previously reported risk factors were detected. It is currently difficult to prevent BO on the basis of the reported risk factors. A novel strategy for the early diagnosis and treatment of BO is required.

Hypoxia, not hypercapnia, induces cardiorespiratory failure in rats

Mechanical respiratory loads induce cardiorespiratory failure, presumably by increasing O2 demand concurrently with decreases in O2 availability (decreased PaO2). We tested the hypothesis that asphyxia alone can cause cardiorespiratory failure (“failure”) in pentobarbital-anesthetized rats. We also tested the hypothesis that hypoxia, not hypercapnia, is responsible by supplying supplemental O2 during mechanical loading in a separate group of rats. Asphyxia (mean PaO2 and PaCO2 of 43 and 69mmHg, respectively) resulted in failure, evident as a slowing of mean respiratory frequency (133–83breaths/min) and a sudden and large drop in mean arterial pressure (71–47mmHg), after 214±66min (n=16; range 117–355min). Neither respiratory drive nor heart rate decreased, indicating that failure was peripheral, not central. Of 8 rats tested after 3h of asphyxia for the presence in blood of cardiac troponin T, all were positive. In an additional 6 rats, normocapnic hypoxia (mean PaCO2 and PaO2 were 39±2.2 and 41±3.1mmHg, respectively) caused failure after an average 205min (range 181–275min), no different from that of asphyxic rats. In the 6 rats that breathed O2 during an initially moderate inspiratory resistive load, endurances exceeded 7h (failure occurring only because we increased the load after 6h) and tracheal pressure and left ventricular dP/dt were maintained despite supercarbia (PaCO2>150mmHg). Thus, asphyxia alone can induce failure, the failure is due to hypoxia, not hypercapnia, and hypercapnia has minimal effects on cardiac and respiratory muscle function in the presence of hyperoxia.

Routine post-operative intensive care is not necessary for children with obstructive sleep apnea at high risk after adenotonsillectomy

ObjectivesPost-operative respiratory adverse events (AE) are frequent in children having adenotonsillectomy (AT) for obstructive sleep apnea (OSA). Many hospitals have a policy of routine admission to the intensive care unit (ICU) after surgery for children at highest risk. We aimed to determine the frequency and severity of post-operative AE in children admitted to ICU, to assess the appropriateness of this care plan. MethodsA retrospective chart review was carried out all children admitted to the pediatric intensive care unit after AT for OSA from January 2007 to December 2009. AE were classified as mild, including requirement for supplemental O2 or repositioning to improve airway or severe, including bag and mask ventilation, CPAP, re-intubation, placement of oropharyngeal airway or unplanned ICU admission for airway compromise. Results72 children were identified (21 female, median age 2.8 years). There were 29 AE in 26 patients (36%), including 23 (31.9%) who suffered a mild AE and 6 (8.3%) who had a severe AE. Age, sex, the presence of co-morbidity or the presence of severe OSA did not predict severe AE in this group. Median time to first AE was 165min. Four of the six severe AE occurred in the post-anesthetic care unit (PACU). There were 60 children who did not have an AE in PACU, of whom 59 did not have a severe AE in the post-operative period, giving a negative predictive value for no worse than a mild AE following an uncomplicated course in PACU of 98.3%. ConclusionsOur data confirm high rates of AE after AT for high risk patients, however, only 8% suffered a severe AE truly necessitating care in ICU. This outcome was very unlikely if an AE did not occur in PACU. We therefore conclude that routine post-operative ICU care for high risk children may be avoided if prolonged monitoring in the PACU is possible, with admission to ICU reserved for high-risk children with an early AE.

Successful management in a pregnant woman with Eisenmenger's syndrome undergoing emergency cesarean section under general anesthesia.

Successful management in a pregnant woman with Eisenmenger's syndrome undergoing emergency cesarean section under general anesthesia.

O2 supplementation to secure the near-infrared spectroscopy determined brain and muscle oxygenation in vascular surgical patients: a presentation of 100 cases

This study addresses three questions for securing tissue oxygenation in brain (rScO2) and muscle (SmO2) for 100 patients (age 71 ± 6 years; mean ± SD) undergoing vascular surgery: (i) Does preoxygenation (inhaling 100% oxygen before anesthesia) increase tissue oxygenation, (ii) Does inhalation of 70% oxygen during surgery prevent a critical reduction in rScO2 (<50%), and (iii) is a decrease in rScO2 and/or SmO2 related to reduced blood pressure and/or cardiac output?Intravenous anesthesia was provided to all patients and the intraoperative inspired oxygen fraction was set to 0.70 while tissue oxygenation was determined by INVOS 5100C. Preoxygenation increased rScO2 (from 65 ± 8 to 72 ± 9%; P < 0.05) and SmO2 (from 75 ± 9 to 78 ± 9%; P < 0.05) and during surgery rScO2 and SmO2 were maintained at the baseline level in most patients. Following anesthesia and tracheal intubation an eventual change in rScO2 correlated to cardiac output and cardiac stroke volume (coefficient of contingence = 0.36; P = 0.0003) rather to a change in mean arterial pressure and for five patients rScO2 was reduced to below 50%. We conclude that (i) increased oxygen delivery enhances tissue oxygenation, (ii) oxygen supports tissue oxygenation but does not prevent a critical reduction in cerebral oxygenation sufficiently, and (iii) an eventual decrease in tissue oxygenation seems related to a reduction in cardiac output rather than to hypotension.

5% CO2 inhalation suppresses hyperventilation-induced absence seizures in children

Hyperventilation can cause respiratory alkalosis by exhaling CO2, and is often used to confirm diagnosis of absence epilepsy. CO2 has long been known for its anticonvulsant properties since the 1920s. In this pilot study, we aimed to determine whether inhaling medical carbogen containing 5% CO2 and 95% O2 can suppress hyperventilation-induced absence seizures and spike-and-wave discharges (SWDs). We examined 12 patients whose absence seizures were induced by hyperventilation using video electroencephalographic recording for at least 4h. The patients were asked to hyperventilate for 3 min while breathing the following gases: (1) room air (12 patients); (2) carbogen (12 patients); and (3) 100% O2 (8 patients). Eight out of twelve patients were also examined in room air through pretreatment with carbogen for 3 min before the 3 min hyperventilation. Compared with hyperventilation in room air, hyperventilation supplemented with 5% CO2 had the following effects: (a) decrease in the number and duration of seizures; (b) prolonged appearance of epileptic discharges; and (c) reduction in the number and duration of SWDs (P<0.001). However, pretreatment with 5% CO2 and 100% O2 supplement did not yield similar effects. We demonstrated that 5% CO2 could suppress hyperventilation-induced absence seizures and SWDs, supporting the claim that 5% CO2 is an effective anticonvulsant agent. Our pilot study provides clinical basis that 5% CO2 inhalation could be a therapeutic approach for hyperventilation-related seizures.

Asthma and hemoglobinopathy: When is supplemental oxygen required?

Asthma is the most common reason for referral to the emergency department in childhood. In severe attacks, supplemental O2 is given when oxygen saturation level is <90%. Described herein is the case of a child with persistent low oxygen saturation as measured on pulse oximetry (S(p)O2) after full clinical recovery from an asthma attack. Simultaneously, P(a)O2 was normal. A diagnosis of abnormal hemoglobin with decreased oxygen affinity (hemoglobin Seattle) was made on hemoglobin electrophoresis and genetic analysis. To ascertain when supplemental oxygen was needed, an oxygen dissociation curve was plotted using the tonometer technique, and it was found that an S(p)O2 of 70% is parallel to a P(a)O2 of 60 mmHg. Plotting an oxygen dissociation curve is a simple reproducible method to determine when supplemental oxygen is required for a child with a hemoglobinopathy.

Surfactant Administration via Thin Catheter during Spontaneous Breathing: Randomized Controlled Trial in Alzahra hospital

Introduction Respiratory distress syndrome (RDS) is a current cause of morbidity in premature infants resulted from surfactant deficiency. The primary aim of this randomized study was to describe the feasibility of early administration of surfactant via a thin catheter during spontaneous breathing (TEC) and compare its outcomes with the InSurE (Intubate, Surfactant, Extubate) procedure Materials and Methods Premature infants with RDS, who were ≤ 32 weeks old and stabilized with nasal continuous positive airway pressure (nCPAP), were randomized to receive surfactant either by the TEC or InSurE technique. Tracheal instillation of 200 mg/kg Curosorf via 5-F catheter during spontaneous breathing under nCPAP was performed in the intervention group (n=38). In the InSurE group (n=40), infants were intubated, received positive pressure ventilation for 30 seconds after surfactant instillation, and placed on nCPAP immediately Results Necrotizing enterocolitis rate was significantly lower in TEC group, than InSurE group, [p<0.02, RR=0.49, CI=%95(0.39_0.62)]. But rate of other morbidities did not significant difference between two groups. Although Mechanical ventilation duration did not significant different between two groups (p=0.2), but Total CPAP duration was shorter in TEC group, significantly [P<0.01, RR=8.2, CI=%95 (-37.9_-4.8)]. Need for O2 supplement and mean of total hospital duration was also lower in TEC group, but was not significant, statistically Conclusion The TEC technique is feasible for the treatment of respiratory distress syndrome in infants with very low birth weight and decreases total nCPAP duration, significantly. But Judgment of substitution TEC instead of InSurE as a routine technique need to more studies.

Central sleep-disordered breathing and the effects of oxygen therapy in infants with Prader-Willi syndrome

ObjectivesTo describe breathing patterns in infants with Prader-Willi Syndrome (PWS), as well as the effects of supplemental oxygen (O2) on breathing patterns. Children with PWS commonly have sleep-disordered breathing, including...

Pulmonary hypertension and the right ventricle in hypoxia

Hypoxia causes pulmonary vasoconstriction. Regional hypoxic vasoconstriction improves the matching of perfusion to alveolar ventilation. Global hypoxic vasoconstriction increases right ventricular afterload. The hypoxic pulmonary pressor response is universal in mammals and in birds, but with considerable interspecies and interindividual variability. Chronic hypoxia induces pulmonary hypertension in proportion to initial vasoconstriction. Prolonged hypoxic exposure is also associated with an increase in red blood cell mass, which aggravates pulmonary hypertension by an increase in blood viscosity. Hypoxic pulmonary hypertension in humans is usually mild to moderate, but pulmonary vascular pressure-flow relationships are steep, which corresponds to a substantial afterload on the right ventricle during exercise. A partial recovery of 10-25% of the hypoxia-induced decrease in maximal oxygen uptake has been reported with intake-specific pulmonary vasodilating interventions. Hypoxia has been reported to decrease myocardial fibre contractility in vitro. However, the acutely hypoxic right ventricle remains able to preserve the coupling of its contractility to increased afterload in intact animals. Echocardiographic studies of the right ventricle in healthy hypoxic human subjects show altered diastolic function, but systolic function that is preserved or even increased acutely and slightly depressed chronically. These findings are more pronounced in patients with chronic mountain sickness. Their clinical significance remains incompletely understood. Almost no imaging studies of right ventricular function have been reported in a minority of subjects who develop severe pulmonary hypertension and clinical right ventricular failure in hypoxia. No imaging studies of right ventricular function during hypoxic exercise in normal subjects are yet available. Thus, while it is plausible that the right ventricle limits exercise capacity in hypoxia, this still needs to be firmly established.

In Vitro Evaluation of Heat and Moisture Exchangers Designed for Spontaneously Breathing Tracheostomized Patients

Heat and moisture exchangers (HMEs) are commonly used in chronically tracheostomized spontaneously breathing patients, to condition inhaled air, maintain lower airway function, and minimize the viscosity of secretions. Supplemental oxygen (O2) can be added to most HMEs designed for spontaneously breathing tracheostomized patients. We tested the efficiency of 7 HMEs designed for spontaneously breathing tracheostomized patients, in a normothermic model, at different minute ventilations (VE) and supplemental O2 flows. HME efficiency was evaluated using an in vitro lung model at 2 VE (5 and 15 L/min) and 4 supplemental O2 flows (0, 3, 6, and 12 L/min). Wet and dry temperatures of the inspiratory flow were measured, and absolute humidity was calculated. In addition, HME efficiency at 0, 12, and 24 h use was evaluated, as well as resistance to flow at 0 and 24 h. The progressive increase in O2 flow from 0 to 12 L/min was associated with a reduction in temperature and absolute humidity. Under the same conditions, this effect was greater at lower VE. The HME with the best performance provided an absolute humidity of 26 mg H2O/L and a temperature of 27.8 °C. No significant changes in efficiency or resistance were detected during the 24 h evaluation. The efficiency of HMEs in terms of temperature and absolute humidity is significantly affected by O2 supplementation and V(E).

Longitudinal neurodevelopmental and neuromotor outcome in congenital diaphragmatic hernia patients in the first 3 years of life

The objective of this study was to longitudinally evaluate the neurodevelopmental (ND) outcome in congenital diaphragmatic hernia (CDH) survivors during the first 3 years of life. The study cohort consists of 47 CDH survivors that were enrolled in our prospective, follow-up program between July 2004 and September 2010, and underwent serial ND evaluations during the first 3 years of life. ND outcomes were evaluated using the Bayley Scales of Infant Development (BSID)-II or BSID-III. Persistent ND impairment was defined as a score that remained 79 for the cognitive, language and psychomotor domains at the most recent follow-up visit compared with the first assessment. The median age at first and last evaluation was 8 (range, 5 to 15) and 29 (range, 23 to 36) months, respectively. During the follow-up, ND scores improved to average in 17%, remained average in 60%, remained delayed in 10%, improved from severely delayed to mildly delayed in 2% and deteriorated from average to delayed in 15%. Motor scores improved to average in 26%, remained average in 55%, remained delayed in 8% and improved from severely delayed to mildly delayed in 11%. Intrathoracic liver position (P=0.004), preterm delivery (P=0.03), supplemental O2 requirement at day of life 30 (P=0.007), age at discharge (P=0.03), periventricular leukomalacia (PVL; P=0.004) and initial neuromuscular hypotonicity (P=0.01) were associated with persistent motor delays. No relationship was found between patient's characteristics and the risk of persistent cognitive and language delays. (1) The majority of children with CDH are functioning in the average range by early preschool age, (2) most children who had early delays showed improvement in their ND outcome, (3) children showing delays in all the three domains were the least likely to show improvement and (4) CDH severity appears to be predictive of persistent psychomotor delays.

Cerebral oxygenation during hyperoxia-induced increase in exercise tolerance for untrained men

This study aimed to investigate the involvement of cerebral oxygenation in limitation of maximal exercise. We hypothesized that O2 supplementation improves physical performance in relation to its effect on cerebral oxygenation during exercise. Eight untrained men (age 27 ± 6 years; VO2 max 45 ± 8 ml min(-1) kg(-1)) performed two randomized exhaustive ramp exercises on a cycle ergometer (1 W/3 s) under normoxia and hyperoxia (FIO2 = 0.3). Cerebral (ΔCOx) and muscular (ΔMOx) oxygenation responses to exercise were monitored using near-infrared spectroscopy. Power outputs corresponding to maximal exercise intensity, to threshold of ΔCOx decline (ThCOx) and to the respiratory compensation point (RCP) were determined. Power output (W max = 302 ± 20 vs. 319 ± 28 W) and arterial O2 saturation estimated by pulse oximetry (SpO2 = 95.7 ± 0.9 vs. 97.0 ± 0.5 %) at maximal exercise were increased by hyperoxia (P < 0.05). However, the ΔMOx response during exercise was not significantly modified with hyperoxia. RCP (259 ± 17 vs. 281 ± 25 W) and ThCOx (259 ± 23 vs. 288 ± 30 W) were, however, improved (P < 0.05) with hyperoxia and the ThCOx shift was related to the W max improvement with hyperoxia (r = 0.71, P < 0.05). The relationship between the change in cerebral oxygenation response to exercise and the performance improvement with hyperoxia supports that cerebral oxygenation is limiting the exercise performance in healthy young subjects.

CPAP for Obstructive Sleep Apnea in the Post-Operative Setting: An Oximetry Evaluation Study

Objective: To study the prevalence and associations of nocturnal hypoxia following surgery in PAP-treated (CPAP or bilevel pressure support) OSA patients. Patients and Methods: PAP-treated OSA patients presenting for elective surgery (n=38) between August 2007 and October 2008 underwent overnight oximetry monitoring on their prescribed PAP therapy on postoperative night one. The lowest oxygen (O2) saturation (SpO2), time spent with SpO2 <89% and the presence of sleep disordered breathing (saw-tooth oscillations) were determined from the oximetry tracings. Need for supplemental O2, nursing/ respiratory interventions, and complications were recorded. Records were reviewed for the type and duration of surgery and anesthesia, net fluid balance, narcotic / sedative use, demographics and co-morbidities. Results: Seven of 38 subjects (18.4%) spent at least 30 minutes with SpO2 <90% during the night (hypoxic group=HG) on their prescribed PAP therapy. The severity of baseline OSA (total and supine apnea-hypopnea index), pre-CPAP SpO2 (asleep on diagnostic PSG and awake evening after surgery), net fluid balance, and total IV narcotic dose were associated with the HG. Nursing interventions and addition of O2 were more common in the HG, though other adverse events were not. Review of the oximetry tracings suggested 71% of the HG, and 42% of the non-hypoxic group, had findings of uncontrolled sleep apnea. Conclusions: Despite the use of prescribed PAP therapy the night following surgery, some OSA patients become hypoxic. Postoperative oximetry monitoring may be indicated in PAP-treated OSA patients undergoing surgery

L‐carnitine improves hydrogen peroxide‐induced impairment of nuclear maturation in porcine oocytes

We investigated the effect of oxidative stress induced by hydrogen peroxide (H2 O2 ) on lipid peroxide (LPO) level and nuclear maturation in porcine oocytes cultured with or without cumulus cells. After 22 h of pre-culture, oocytes with attached cumulus cells (COC group) or denuded oocytes (DO group) were cultured with H2 O2 , and intra-oocyte H2 O2 and LPO levels were quantitatively analyzed using immunofluorescence. This is the first report evaluating LPO levels in porcine oocytes. After H2 O2 supplementation, the DO group showed severe accumulation of H2 O2 and LPO in the oocytes. Similarly, while inhibition of progression of nuclear maturation was observed in both groups, the effect was more severe in the DO group. These results demonstrate that cumulus cells reduce the accumulation of H2 O2 stress in oocytes. Furthermore, we attempted to reduce the oxidative stress by H2 O2 with L-carnitine, a H2 O2 scavenger. L-carnitine decreased H2 O2 and LPO levels in the oocytes in both groups, and improvement in the progression of impaired nuclear maturation was observed. These effects were different by the presence of cumulus cells. Our results provide that L-carnitine is useful for alleviating H2 O2 -induced oxidative stress by reducing LPO levels and improving the progression of nuclear maturation.

Treatment of Central Sleep Apnea in US Veterans

There are no standard therapies for the management of central sleep apnea (CSA). Either positive pressure therapy (PAP) or supplemental oxygen (O(2)) may stabilize respiration in CSA by reducing ventilatory chemoresponsiveness. Additionally, increasing opioid use and the presence of comorbid conditions in US veterans necessitates investigations into alternative titration protocols to treat CSA. The goal was to report on the effectiveness of titration with PAP, used alone or in conjunction with O(2), for the management of CSA associated with varying comorbidities and opioid use. This was a retrospective chart review over 3 years, performed at a VA sleep disorders center. The effects of CPAP, CPAP+O(2), and BPAP+O(2), used in a step-wise titration protocol, on consecutive patients diagnosed with CSA were studied. CSA was diagnosed in 162 patients. The protocol was effective in eliminating CSA (CAI ≤ 5/h) in 84% of patients. CPAP was effective in 48%, while CPAP+O(2) combination was effective in an additional 25%, and BPAP+O(2) in 11%. The remaining 16% were non-responders. Forty-seven patients (29%) were on prescribed opioid therapy for chronic pain, in whom CPAP, CPAP+O(2), or BPAP+O(2) eliminated CSA in 54%, 28%, and 10% cases, respectively. CPAP, CPAP+O(2), and BPAP+O(2) each produced significant declines in the AHI, CAI, and arousal index, and an increase in the SpO(2). The data demonstrate that using a titration protocol with CPAP and then PAP with O(2) effectively eliminates CSA in individuals with underlying comorbid conditions and prescription opioid use. Comparative studies with other therapeutic modalities are required.