Negative Intrathoracic Pressure Research Articles

DESCENDING NECROTIZING MEDIASTINITIS (DNM) DISGUISING AS A MEDIASTINAL MASS

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: DNM is an uncommon infection arising in the head or neck which tracks between the cervical fascial planes into the mediastinum. We report a case of DNM with a challenging presentation. CASE PRESENTATION: A 56-year-old male on chronic hemodialysis recovering from COVID pneumonia, presented to the emergency department with 2 days of shortness of breath. He was hypertensive, tachycardic and hypoxic, in respiratory distress, requiring immediate initiation of noninvasive ventilation. Shortly after arrival, he went into cardiac arrest. Resuscitation efforts were successful. Intensive management included mechanical ventilation, broad spectrum antibiotics, vasopressors and continuous renal replacement therapy for suspected septic shock. Chest x-ray showed mediastinal widening, confirmed by CT, to be due to a 7.5 cm lobulated, soft tissue density in the mediastinum impinging on the trachea. Bronchoscopy via endotracheal tube showed no obstruction except for some dynamic airway collapse. Trans-bronchial needle aspiration of the mediastinal mass was non-diagnostic. In 2 days, he improved, was extubated but then emergently re-intubated due to acute upper airway obstruction. Repeat imaging revealed a large retropharyngeal abscess extending from C1 level to the thyroid gland. It wrapped around anteriorly and communicated with a large collection in the superior mediastinum surrounding the trachea. Also noted was an enlarging pleural effusion. Urgent surgical drainage of the retropharyngeal space, superior mediastinum and pleural fluid was performed. Cultures grew Staphylococcus aureus. Mediastinal exploration and tracheostomy followed. He steadily improved and was discharged. DISCUSSION: DNM is a life-threatening infection that originates in the neck;retropharyngeal abscess in this case. It spreads caudally through cervical fascial planes facilitated by gravity and negative intrathoracic pressures (1). Oral flora are the usual pathogens (2). Diagnosis needs a high index of suspicion to obtain necessary imaging. Favorable outcomes are seen with early diagnosis, airway protection, antibiotics and timely surgical drainage (3).Our patient had narrowing of the proximal trachea due to compression from the fluid collection requiring emergent re-intubation. His initial chest CT reported a soft tissue density concerning for malignancy. It was the second CT that suggested an abscess. Looking back, prior chest x-rays showed progressive mediastinal widening over 10 days, making malignancy less likely. Review of old imaging remains invaluable. CONCLUSIONS: Deep neck infection leading to mediastinitis requires early diagnosis, antibiotic administration as well as operative management for source control. REFERENCE #1: Benedetto C, et al. Catastrophic descending necrotizing mediastinitis of the anterior and posterior compartments: A case report. Radiol Case Rep. 2020;15(10):1832-1836 REFERENCE #2: Brook I, Frazier EH. Microbiology of mediastinitis. Arch Intern Med. 1996 Feb 12;156(3):333-6. Erratum in: Arch Intern Med 1996 May 27;156(10):1112. PMID: 8572845. REFERENCE #3: Ridder GJ, Maier W, Kinzer S, Teszler CB, Boedeker CC, Pfeiffer J. Descending necrotizing mediastinitis: contemporary trends in etiology, diagnosis, management, and outcome. Ann Surg. 2010 Mar;251(3):528-34. doi: 10.1097/SLA.0b013e3181c1b0d1. PMID: 19858699. DISCLOSURES: No relevant relationships by Rana Hejal, source=Web Response No relevant relationships by Willie McClure, source=Web Response No relevant relationships by Tanmay Panchabhai, source=Web Response No relevant relationships by Layla Sankari, source=Web Response No relevant relationships by Apoorwa Thati, source=Web Response

Characterization of fecal metabolome changes in patients with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a clinical syndrome characterized by recurrent episodes of apnea or hypopnea of the upper airway, leading to increased negative intrathoracic pressure, sleep fragmentation, intermittent hypoxia during sleep, and increased risk for morbidity and mortality of affected patients. The gut microbiome plays a key role in OSA pathogenesis, and fecal metabolic profiling reflects the gut microbial functional readout and mediates host-microbiome interactions. Herein, we conducted a cohort study to explore fecal metabolic signatures distinguishing OSA (44 patients) from healthy controls (22 healthy controls) by untargeted gas chromatography-time-of-flight mass spectroscopy. Significant metabolic signatures were detected in stool samples of patients with OSA: 246 metabolites of 24 ontology classes were identified, and 48 metabolites of 6 ontology classes were shifted. An enrichment of arachidonic acid, docosahexaenoic acid, and 11Z-eicosenoic acid and reduction in stearic acid, 5-hydroxyindoleacetic acid, gluconic acid, and α-hyodeoxycholic acid were observed in stool samples from patients with OSA. Fecal variance resulted in alterations in potential metabolic activities and was thereby strongly associated with host phenotypes, such as pulse blood oxygen saturation and apnea-hypopnea index. The prediction model based on feces metabolomics was established to distinguish OSA from healthy controls with high accuracy. This study revealed the metabolomic signatures of patients with OSA in feces, and the findings provide evidence of an association between metabolome and OSA. Dong Y, Wang P, Lin J, et al. Characterization of fecal metabolome changes in patients with obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):575-586.

Abstract P159: Moderate To Severe Obstructive Sleep Apnea Is Independently Associated With Inter-arm Systolic Blood Pressure Difference: Tokyo Sleep Heart Study

Objective: Obstructive sleep apnea (OSA) is recognized as an independent risk factor for cardiovascular disease. On the other hand, inter-arm systolic blood pressure difference (IAD), inter-ankle systolic blood pressure difference (IAND), and ankle-brachial index (ABI) are all known predictors of cardiovascular events. The aim of the present study was to investigate the association between OSA and four-limb blood pressure differences. Methods: We conducted this cross-sectional study in a large sleep cohort from Tokyo Sleep Heart Study. In 2643 consecutive patients who visited our sleep clinic for polysomnography between 2005 and 2017; all the subjects underwent blood pressure measurement simultaneously in all the four limbs by oscillometric methods. Results: The prevalence rate of IAD ≥ 10 mm Hg was significantly higher in the severe OSA (apnea-hypopnea index ≥ 30) group (4.6%) than in the no/mild (apnea-hypopnea index < 15) OSA group (1.6%). Multivariate logistic regression analysis also identified moderate to severe OSA as being significantly associated with IAD ≥ 10 mm Hg, even after adjustments for confounding variables [moderate OSA; odds ratio (OR): 3.627, 95% confidence interval (CI): 1.056-12.465, P = 0.041. Severe OSA; OR: 3.778, 95% CI: 1.113-12.595, P = 0.031]. However, there were no significant associations of the OSA severity with IAND ≥ 15 mm Hg or ABI < 0.9. Conclusions: Moderate to severe OSA was independently associated with the IAD, not but with the IAND or ABI. The plausible explanation is that the negative intrathoracic pressure caused by OSA may exert an adverse impact on the structural properties of the thoracic aorta. Our findings emphasized that physicians should be careful of IAD, easily applied clinical tool, to evaluate subclinical cardiovascular damage and cardiovascular risk in patients with OSA.

Impact of nocturnal oxygen and CPAP on the ventilatory response to hypoxia in OSA patients free of overt cardiovascular disease

A primary characteristic of obstructive sleep apnea (OSA) is chronic exposure to intermittent hypoxia (IH) due to repeated upper airway obstruction. Chronic IH exposure is believed to increase OSA severity over time by enhancing the acute ventilatory response to hypoxia (AHVR), thus promoting ventilatory overshoot when apnea ends and perpetuation of apnea during sleep. Continuous positive airway pressure (CPAP), the gold-standard treatment of OSA, reduces the AHVR, believed to result from correction of IH. However, CPAP also corrects ancillary features of OSA such as intermittent hypercapnia, negative intrathoracic pressure and surges in sympathetic activity, which may also contribute to the reduction in AHVR. Therefore, the objective of this study was to investigate the impact of nocturnal oxygen therapy (to remove IH only) and CPAP (to correct IH and ancillary features of OSA) on AHVR in newly diagnosed OSA patients. Fifty-two OSA patients and twenty-two controls were recruited. The AHVR was assessed using a 5 min iscopanic-hypoxic challenge before, and after, treatment of OSA by nocturnal oxygen therapy and CPAP. Following baseline measurements, OSA patients were randomly assigned to nocturnal oxygen therapy (Oxygen, n = 26) or no treatment (Air; n = 26). The AHVR was re-assessed following two weeks of oxygen therapy or no treatment, after which all patients were treated with CPAP. The AHVR was quantified following ~4 weeks of adherent CPAP therapy (n = 40). Both nocturnal oxygen and CPAP treatments improved hypoxemia (p < 0.05), and, as expected, nocturnal oxygen therapy did not completely abolish respiratory events (i.e., apneas/hypopneas). Averaged across all OSA patients, nocturnal oxygen therapy did not change AHVR from baseline to post-oxygen therapy. Similarly, the AHVR was not altered pre- and post-CPAP (p > 0.05). However, there was a significant decrease in AHVR with both nocturnal oxygen therapy and CPAP in patients in the highest OSA severity quartile (p < 0.05). Nocturnal oxygen therapy and CPAP both reduce the AHVR in patients with the most severe OSA. Therefore, IH appears to be the primary mechanism producing ventilatory instability in patients with severe OSA via enhancement of the AHVR.

A new approach to improve the hemodynamic assessment of cardiac function independent of respiratory influence

Cardiovascular and respiratory systems are anatomically and functionally linked; inspiration produces negative intrathoracic pressures that act on the heart and alter cardiac function. Inspiratory pressures increase with heart failure and can exceed the magnitude of ventricular pressure during diastole. Accordingly, respiratory pressures may be a confounding factor to assessing cardiac function. While the interaction between respiration and the heart is well characterized, the extent to which systolic and diastolic indices are affected by inspiration is unknown. Our objective was to understand how inspiratory pressure affects the hemodynamic assessment of cardiac function. To do this, we developed custom software to assess and separate indices of systolic and diastolic function into inspiratory, early expiratory, and late expiratory phases of respiration. We then compared cardiac parameters during normal breathing and with various respiratory loads. Variations in inspiratory pressure had a small impact on systolic pressure and function. Conversely, diastolic pressure strongly correlated with negative inspiratory pressure. Cardiac pressures were less affected by respiration during expiration; late expiration was the most stable respiratory phase. In conclusion, inspiration is a large confounding influence on diastolic pressure, but minimally affects systolic pressure. Performing cardiac hemodynamic analysis by accounting for respiratory phase yields more accuracy and analytic confidence to the assessment of diastolic function.

Trans-hyoid hyoidthyroidpexy: A modified technique for selected cases of obstructive sleep apnea

ObjectiveHypopharyngeal collapse (HC) considered a challenge in surgery of obstructive sleep apnea (OSA). Several procedures were presented to deal with HC indirectly via providing support to the lateral walls of the hypopharynx preventing transverse collapse but hyoidthryoidpexy had gained more popularity. The procedure aimed to fix the mobile hyoid bone to a rigid mid-line neck structure, thus preventing the bone and its attached muscles from collapsing during sleep with the negative intrathoracic pressure on inspiration. Study designA prospective case series study. MethodsFrom April 2018 to January 2020, A Modified Technique of Trans hyoid hyoidthyroidpexy was applied for all included patients (24) patients with symptoms of OSA showing predominant lateral wall collapse of the hypopharynx (with retro-palatal collapse) with other OSA surgery. Results6–8 months postoperatively, the Apnea Hypopnea index dropped from 43.75 ± 8.44 to 16.28 ± 7.35 (P < 0.0001; t = 10.6988). 14 patients (58.33%) were reported as successful while 7 patients (29.17%) were considered responders and three patients (12.5%) were considered non responders. The mean lowest oxygen desaturation elevated from 77.56 ± 5.64 to 92.38 ± 6.25 (p < 0.0001). Epworth Sleepiness Scale improved (P < 0.0001) from 16.85 ± 4.23 to 5.17 ± 3.89. ConclusionTrans-hyoid hyoidthyroidpwxy is a modified technique of hyoidthyroidpexy. The procedure reported good outcomes in treating OSA. It is a simple, cost-effective and less traumatic technique. It could be combined with other multilevel surgical procedures.

Intrathoracic calculous cholecystitis due to delayed iatrogenic diaphragmatic hernia

Iatrogenic diaphragmatic hernias is rare complications of abdominal or thoracic surgery. Depending on the location and size of the defect retroperitoneal or intra-abdominal organs and tissues can prolapse into thoracic cavity due to the negative intra-thoracic pressure. This can cause risk of obstruction or strangulation of abdominal contents, and may ischemia and perforation. We present a case of delayed presentation of a patient with iatrogenic diaphragmatic herniation of liver and gallbladder with stones into the thorax. A 62-year-old female was visited our hospital for complaining of right sided thoracic back pain during 3month. The pain had not been treated with analgesics. Three years ago, she has been diagnosed right diaphragmatic metastatic nodule from ovarian cancer. She was operated excisional biopsy of intrathoracic lymph nodes and parietal pleural by VATs (video-assisted thoracic surgery). A computed tomography-scan showed intrathoracic displacement of her liver and chronic cholecystitis with multiple stones. The patients underwent laparotomy via an abdominal approach with subcostal incision. Intraoperative findings confirmed that right diaphragmatic focal defect and liver and gallbladder herniated into the thoracic cavity. The organs were placed back into the thoracic cavity. A cholecystectomy was performed, and the defect in the diaphragm measuring 13 cm × 10 cm, was repaired with a Gortex graft. Postoperative recovery was uneventful. The patient was discharged seven days after the surgery without any problems.

Characteristics Of Patients Of Descending Necrotizing Mediastinitis Thoracic, Cardiac And Vascular Surgery Subsection Thoracic In Dr. Mohammad Hoesin From 1 November 2019 To 30 November 2020

Background: Acute mediastinitis is an infection of the connective tissue of the interpleural mediastinal space. The infection may spread through the cervical spaces to the mediastinum, via negative intrathoracic pressure and gravity.1 Management of DNM with minimally invasive drainage, namely video-assisted thoracic surgical drainage (VATS),6 mediastinoscopy,7 and percutaneous catheter drainage,8,9 have been widely used. During early 1920s, data showed subsequent to broad-spectrum antibiotics, the mortality rate was about 40%.12 Furthermore, without prompt diagnosis and aggressive surgery, the mortality rate can reach up to 60%.13&#x0D; Methods: This retrospective study has a descriptive research design. The number of samples is 19 subjects.&#x0D; Results: From January 1, 2019 to November 30, 2020 there were 19 DNM patients. In this study, most DNM patients were male, average age of 39 years, dental abscesses as the most common source of infection, neck exploration and sternotomy were the most common treatment option, most common outcome death, and the most common result of culture was Acinetobacter baumannii.&#x0D; Conclusion: Good non-operative and operative management can reduce mortality rate.

Edema polmonare da pressione negativa dopo settoplastica in un adolescente

Negative pressure pulmonary edema (NPPE) is a danger-ous and potentially fatal condition with a multifactorial pathogenesis. NPPE is frequently a manifestation of upper airway obstruction, indeed the large negative intrathoracic pressure generated by forced inspiration against an obstructed airway is thought to be the main mechanism involved. The early detection of the signs of this syndrome is vital to the treatment and to patient outcome. The paper presents a case of NPPE due to post-extubation laryngospasm in a 14-year-old patient.

Saving the brain after mild-to-moderate traumatic injury: A report on new insights of the physiology underlying adequate maintenance of cerebral perfusion.

Traumatic brain injury (TBI) is associated with increased morbidity and mortality in civilian trauma and battlefield settings. It has been classified across a continuum of dysfunctions, with as much as 80% to 90% of cases diagnosed as mild to moderate in combat casualties. In this report, a framework is presented that focuses on the potential benefits for acute noninvasive treatment of reduced cerebral perfusion associated with mild TBI by harnessing the natural transfer of negative intrathoracic pressure during inspiration. This process is known as intrathoracic pressure regulation (IPR) therapy, which can be applied by having a patient breath against a small inspiratory resistance created by an impedance threshold device. Intrathoracic pressure regulation therapy leverages two fundamental principles for improving blood flow to the brain: (1) greater negative intrathoracic pressure enhances venous return, cardiac output, and arterial blood pressure; and (2) lowering of intracranial pressure provides less resistance to cerebral blood flow. These two effects work together to produce a greater pressure gradient that results in an improvement in cerebral perfusion pressure. In this way, IPR therapy has the potential to counter hypotension and hypoxia, potentially significant contributing factors to secondary brain injury, particularly in conditions of multiple injuries that include severe hemorrhage. By implementing IPR therapy in patients with mild-to-moderate TBI, a potential exists to provide early neuroprotection at the point of injury and a bridge to more definitive care, particularly in settings of prolonged delays in evacuation such as those anticipated in future multidomain operations. Report.

Rumination syndrome. A review article.

Rumination syndrome is a functional gastrointestinal disorder characterized by effortless postprandial regurgitation of ingested food into the mouth. An unperceived postprandial contraction of the abdominal wall could be a key mechanism. In those patients, retrograde flow of the ingested gastric content into the mouth is produced due to a simultaneous combination of elevated intra-abdominal pressure and negative intrathoracic pressure. The estimated prevalence is around 2% in the general adult population. The main clinical characteristics include: a) early postprandial regurgitation, b) the effortlessly regurgitated material is similar to the ingested food, c) the regurgitated material is spit out or swallowed again. The clinical diagnosis of rumination syndrome relies on the clinical criteria. High resolution esophageal manometry, ideally including impedance monitoring, can be an important adjunct for making the clinical diagnosis. Its management is based on instruction as to the nature of the pathology, education in postprandial diaphragmatic breathing, and the assessment of possible psychiatric comorbidity. Baclofen use is reserved for second-line treatment in patients with refractory symptoms.

INTER-ARM BLOOD PRESSURE DIFFERENCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA

Objective: Obstructive sleep apnea (OSA) is an independent risk for cardiovascular disease. On the other hand, inter-arm systolic blood pressure difference (IAD) is noted as a marker for future cardiovascular events. However, underlying mechanisms of IAD has not been fully clarified. The present study was conducted to examine whether OSA is associated with IAD. Design and method: In 2645 consecutive patients aged over 30 {age: 56 ± 13 years old, mean apnea-hypopnea index (AHI): 39 ± 23 /h}, who visited sleep clinic to perform polysomnography in 2005–2017, blood pressure in both arms were measured simultaneously by oscillometric methods. The IAD was defined as absolute value of the systolic blood pressure difference in both arms. Results: In all included patients, patients with IAD over 10 mmHg were noted in 3.7%. When patients were divided into two groups: severe OSA (AHI over 30) group and mild to moderate OSA (AHI &lt; 30) group, the prevalence rate of IAD over 10 mmHg were higher in severe OSA group than those in mild to moderate group (4.6% vs 2.8%, P &lt; 0.05)(Figure). Multiple linear regression analysis demonstrated that AHI was an independent (P &lt; 0.05) determinant of IAD, even after the adjustments of age, gender, body mass index, hypertension, and another variables. Conclusions: OSA may be a risk for IAD. The plausible explanation is that pathophysiological abnormalities related with OSA, such as the negative intrathoracic pressure, may affect IAD.

63 Nocturia—An Underappreciated “Symptom” of Obstructive Sleep Apnoea?

Abstract Nocturia (&amp;gt;2 per night) is the most frequent cause of disturbed sleep in older people. Poor sleep results in reduced health related QoL, and is linked to the development of cognitive impairment. Nocturia can result in an increase risk of falls and fractures, and is also an independent risk factor for mortality. The prevalence of norturia is high in the elderly, and it has been reported to be around 77.1% in elderly women and 93% in men. Historically, this bothersome symptom is thought to be mainly a result of bladder outflow obstruction due to prostatic hypertrophy or overactive bladder. More recently, nocturia has been associated witsh nocturnal polyuria (NPu) and obstructive sleep apnoea (OSA). The relationship between OSA and NPu is not fully understood but it is thought that the negative intrathoracic pressure generated by OSA causes an increase in Atrial Natriuretic Peptide (ANP) secretion, resulting in NPu. Nocturia is highly prevalent in patients with severe OSA. However, patients are usually unaware that they have sleep apnoea, and are therefore more likely to present to urology or geriatric services. It is important that OSA is not overlooked in these clinics as intervention with CPAP is highly effective in reducing symptoms. Here, we present the result of using the STOP-Bang questionnaire in 71 consecutive patients presenting to our urology service with nocturia. The average age was 73 years (range 34-88), male-to-female ratio 14:1 and median nocturia frequency of 4. 42 patients were at risk of undiagnosed sleep apnoea (median STOP-Bang Score of 5)—35 were referred for sleep studies, 4 patients declined and 3 patients were not referred. Overall, 31 out of 35 sleep studies (88.6%) demonstrated the presence of OSA; of these 23 (74.2%) confirmed moderate or severe OSA. All patients with OSA were seen and treated by the respiratory service. Overall, median nocturia frequency decreased from 4 to 1 across the whole cohort, from a combination of CPAP therapy, bladder outlet procedures and desmopressin. Conclusion At least a third of patients (32%) with bothersome nocturia have an undiagnosed clinically-significant OSA. Identification of OSA improves outcomes across the whole cohort, because nocturia in patients without OSA is more likely to respond to bladder outlet procedures and desmopressin.

Systolic reserve maintains left ventricular-vascular coupling when challenged by adverse breathing mechanics and hypertension in healthy adults.

Augmented negative intrathoracic pressures (nITP) and dynamic hyperinflation (DH) are adverse breathing mechanics (ABM) associated with chronic obstructive pulmonary disease (COPD) that attenuate left ventricular (LV) preload and augment afterload. In COPD, hypertension (elevated systemic arterial load) commonly adds additional afterload to the LV. Combined ABM and hypertension may profoundly challenge ventricular-vascular coupling and attenuate stroke volume (SV), particularly if LV systolic reserve is limited. However, even in the healthy heart, the combined impact of ABM and systemic arterial loading on LV function and ventricular-vascular coupling has not been fully elucidated. Healthy volunteers (10 M/9 F, 24 ± 3 yr old) were challenged with mild (-10 cmH2O nITP and 25% DH) and severe (-20 cmH2O nITP and 100% DH) ABM, without and with postexercise ischemia (PEI) at each severity. LV SV, chamber geometry, end-systolic elastance (Ees), arterial elastance (Ea), and ventricular-vascular coupling (Ees:Ea) were quantified using echocardiography. Compared with resting control (58 ± 13 mL), SV decreased during mild ABM (51 ± 13 mL), mild ABM + PEI (51 ± 11 mL), severe ABM (50 ± 12 mL), and severe ABM + PEI (47 ± 11 mL) (P < 0.001); similar trends were observed for LV end-diastolic volume. The end-diastolic radius of septal curvature increased, indicating direct ventricular interaction, during severe ABM and severe ABM + PEI (P < 0.001). Compared with control (1.99 ± 0.41 mmHg/mL), Ea increased progressively with mild ABM (2.21 ± 0.47 mmHg/mL) and severe ABM (2.50 ± 0.56 mmHg/mL); at each severity, Ea was greater with superimposed PEI (P < 0.001). However, well-matched Ees increases occurred, and Ees:Ea was unchanged throughout. ABM pose a challenge to ventricular-vascular coupling that is accentuated by superimposed PEI; however, in healthy younger adults, the LV has substantial systolic reserve to maintain coupling.NEW & NOTEWORTHY In healthy younger adults, combined dynamic hyperinflation (DH) and negative intrathoracic pressures (nITP) attenuate left ventricular filling, but through different mechanisms at different severities. DH and nITP contribute to increased left ventricular afterload through mechanical effects in addition to presumed reflexive regulation, which can be further increased by elevated arterial loading. However, within this demographic, the left ventricle has substantial reserve to increase systolic performance, which matches contractility to afterload to preserve stroke volume.

The Impact of Time to Intubate Towards Mortality Rate Among Covid-19 Patients in Dr. Soetomo General Hospital Resuscitation and ICU

Backgrounds: The COVID-19 pandemic began to spread in Indonesia in March 2020 and continues to increase. Patients with severe symptoms are known to have impaired oxygenation leading to hypoxaemia. Severe oxygenation disorders can be seen from clinical symptoms of respiratory distress and examination of blood gas analysis with a low PF ratio. Patients with respiratory distress should be assisted by administering a High-Flow Nasal Cannula to mechanical ventilation. Patients who experience respiratory distress for a long time will cause a decrease in negative intrathoracic pressure which can cause interstitial pulmonary edema and will lead to an increase in mortality. Therefore, this study was prepared with the aim of analyzing the effect of intubation time on mortality of Covid-19 patients in a special resuscitation and infection room at a hospital in Indonesia. Methods: This study is a retrospective analytic observational study with a sample of 35 subjects. This study uses the criteria for respiratory distress through the 3rd edition of the COVID-19 Management Guidelines with the RR criteria&gt; 30 times per minute. Results: The results showed that the median mortality of patients during intubation was 8 hours, while the median mortality of patients from the time the patient entered the intensive care unit until intubation was 6 hours. Conclusion: Therefore, it can be concluded that the shorter the intubation time and the time to enter the intensive care unit until intubation is carried out in Covid-19 patients, the lower the patient mortality rate.

Gastroesophageal Intussusception in Canine

Background: Gastroesophageal intussusception is characterized by the invagination of the stomach into the esophagus, with or without the involvementof adjacent organs such as the spleen, pancreas, and omentum. In dogs, this condition has no breed or sex predisposition. As it is an infrequent disease in routine veterinary medical practice, this study reports a case of gastroesophageal intussusception in a dog necropsied at the Veterinary Hospital of the Federal Rural University of Pernambuco (HOVET - UFRPE), Recife, Brazil.Case: The body of a 12-year-old black mixed breed male dog was sent to the Pathology Department (Necropsy Sector of the Federal Rural University of Pernambuco - UFRPE) for a necropsy. The animal had a previous 4-year history of recurrent emesis and limb weakness, primarily in the anterior limbs, that worsened in the previous months and progressed to death. No previous treatments were reported by the owner. On external examination, the animal had a low body score (cachectic), forelimb joints with great flexibility, congested oral and ocular mucous membranes, enophthalmos, and increased volume in the perianal region. At the opening of the thoracic cavity, the final third of the esophagus was dilated and gastroesophageal intussusception, edema, and pulmonary congestion were noted. In the abdominal cavity, there was hepatic and renal congestion and large intestine and rectal ampoule dilation, with a large amount of solid and retained feces (fecaloma), perianal hernia, and testicular neoformation. These findings were consistent with those observed in death caused by cardiorespiratory failure secondary to gastroesophageal intussusception.Discussion: The pathophysiology of gastroesophageal intussusception is still not elucidated and is probably multifactorial. This condition causes reverse gastric peristalsis associated with a sudden and sustained increase in abdominal pressure. Some probable predisposing factors for this pathological condition are esophageal motility disorders, lower esophageal sphincter dysfunction, and hiatal enlargement. In dogs, gastroesophageal intussusception is associated with increased intra-abdominal pressure owing to emesis or blunt trauma, negative intrathoracic pressure caused by respiratory, and previous esophageal diseases, especially megaesophagus. Partial or total obstruction caused by intussusception leads to circulatory disorders in the organs, especially decreased venous return. Persistence of this condition can lead to gastric necrosis and rupture followed by endotoxic (or septic) shock and release of inflammatory mediators that can cause cardiovascular and respiratory dysfunction and rapid death. Impaired circulation is macroscopically evident in several organs, characterized by mucosal, lung, liver, and kidney congestion, in addition to cardiac dilation and mitral valve endocardiosis. The occurrence of stomach invagination into the esophagus dilated in the final portion is characteristic of gastroesophageal intussusception. Moreover, death owing to cardiorespiratory failure is related to cardiac (dilatation and endocardiosis) and pulmonary (edema and congestion) involvement secondary to gastroesophageal intussusception. Since thispotentially fatal condition has a low incidence in small animals and often goes unnoticed by professionals, early and correct diagnosis along with surgical treatment are essential for a good prognosis and favorable progression.

Abstract 129: Gasping During Cardiac Arrest Before Cardiopulmonary Resuscitation Increases Cerebral Oximetry in a Swine Model

Introduction: Spontaneous gasping (SG) during cardiac arrest is associated with favorable neurological outcomes. SG lowers intrathoracic pressure (ITP), enhancing flow of respiratory gases to the lungs and venous blood to the heart, while simultaneously lowering intracranial pressure (ICP). The impact of SG on regional cerebral oximetry (rSO2) is unknown. Hypothesis: During untreated ventricular fibrillation (VF), SG will increase rSO2 until the gasping effort declines. Methods: Swine (~40 kg) were intubated and anesthetized with isoflurane. After 8 min of untreated VF, conventional mechanical CPR at 100 compressions/min was performed. Intrathoracic pressure (ITP), mean aortic pressure (MAP), ICP, right atrial pressure (RAP) and calculated cerebral perfusion pressure (CerPP) were measured continuously. rSO2 was measured continuously with near-infrared spectroscopy (Equanox 7600, Nonin Medical). These parameters were assessed before and during SG, and during CPR. Data are expressed as mean ± SD. A paired Student’s t- test was used. Results: SG occurred in 19/22 pigs during untreated VF, with 9.2 ± 4.3 gasps/pig. For pigs that gasped, the individual gasp duration was 1.74 ± 0.52 sec and the maximum negative ITP (mmHg) was -3.24 ± 1.93 mmHg. rSO2 increased in 9/19 (47%) pigs from 54.7% ± 4.1 to 57.8% ± 4.8 during SG (p&lt;0.001). Figure 1 shows rSO2 from 2 representative pigs, A) with and B) without SG. SG also decreased ITP (p&lt;0.001), RAP (p=0.02) and ICP (p&lt;0.001), and increased MAP (p&lt;0.001) and CerPP (p&lt;0.001). After 8 min of untreated VF, rSO2 for all 22 pigs was 49.3% ± 3.7. After 30 and 60 sec of CPR, rSO2 values were 54.6% ± 3.8 and 57.8% ± 3.8, respectively. Conclusions: rSO2 values increased in nearly half of animals with SG. This increase in rSO2 with SG was equal to the level of rSO2 achieved after 1 minute of CPR. Further study is warranted to determine potential prognostic and therapeutic implications of SG-induced increases rSO2 during cardiac arrest.

Rationale and Strategies for Development of an Optimal Bundle of Management for Cardiac Arrest.

To construct a highly detailed yet practical, attainable roadmap for enhancing the likelihood of neurologically intact survival following sudden cardiac arrest. Population-based outcomes following out-of-hospital cardiac arrest were collated for 10 U.S. counties in Alaska, California, Florida, Ohio, Minnesota, Utah, and Washington. The 10 identified emergency medical services systems were those that had recently reported significant improvements in neurologically intact survival after introducing a more comprehensive approach involving citizens, hospitals, and evolving strategies for incorporating technology-based, highly choreographed care and training. Detailed inventories of in-common elements were collated from the ten 9-1-1 agencies and assimilated. For reference, combined averaged outcomes for out-of-hospital cardiac arrest occurring January 1, 2017, to February 28, 2018, were compared with concurrent U.S. outcomes reported by the well-established Cardiac Arrest Registry to Enhance Survival. Most commonly, interventions and components from the ten 9-1-1 systems consistently included extensive public cardiopulmonary resuscitation training, 9-1-1 system-connected smart phone applications, expedited dispatcher procedures, cardiopulmonary resuscitation quality monitoring, mechanical cardiopulmonary resuscitation, devices for enhancing negative intrathoracic pressure regulation, extracorporeal membrane oxygenation protocols, body temperature management procedures, rapid cardiac angiography, and intensive involvement of medical directors, operational and quality assurance officers, and training staff. Compared with Cardiac Arrest Registry to Enhance Survival (n = 78,704), the cohorts from the 10 emergency medical services agencies examined (n = 2,911) demonstrated significantly increased likelihoods of return of spontaneous circulation (mean 37.4% vs 31.5%; p < 0.001) and neurologically favorable hospital discharge, particularly after witnessed collapses involving bystander cardiopulmonary resuscitation and shockable cardiac rhythms (mean 10.7% vs 8.4%; p < 0.001; and 41.6% vs 29.2%; p < 0.001, respectively). The likelihood of neurologically favorable survival following out-of-hospital cardiac arrest can improve substantially in communities that conscientiously and meticulously introduce a well-sequenced, highly choreographed, system-wide portfolio of both traditional and nonconventional approaches to training, technologies, and physiologic management. The commonalities found in the analyzed systems create a compelling case that other communities can also improve out-of-hospital cardiac arrest outcomes significantly by conscientiously exploring and adopting similar bundles of system organization and care.

The concatenation of association between gastroesophageal reflux and obstructive adenotonsillar hypertrophy

ObjectivesGastroesophageal reflux (GER) is frequently seen in patients with adenotonsillar hypertrophy. However, the sequential association between GER and adenotonsillar hypertrophy is unknown. This leads to unpredictable outcomes while treating patients of adenotonsillar hypertrophy with GER. The objective of this study is to evaluate the prevalence of GER and gastroesophageal reflux disease (GERD) in paediatric patients with obstructive adenotonsillar hypertrophy (OATH), and to assess the effect of adenotonsillectomy (AT) on GER as well as GERD. MethodsIn this prospective cohort study, consecutive pediatric patients with grade III/IV hypertrophy of adenoid or/and tonsillar tissue who were planned for AT were recruited after excluding comorbidities predisposing to GER. Symptoms of GERD using Gastro Esophageal Reflux Questionnaire for Young Children (GERQ-YC) and Reflux Indices (RI) obtained from 24-h ambulatory esophageal pH monitoring were evaluated in all patients pre-operatively and 12 weeks following AT. ResultsA total of 49 patients with OATH with average age of 6 years were included in this study. With a RI of >4.3% as the threshold for making the diagnosis of GER on esophageal pH monitoring, the prevalence of GER was 20.4%. The average RI preoperatively was 15.7% which reduced to 1.7% following AT (p = 0.004). Among the 10 patients with preoperative GER, 80% of the patients had no evidence of GER after surgery. New incidences of GER was not observed post operatively in this cohort. As per the GER symptom scoring system, 31% of the parents reported GERD pre-operatively which resolved completely in all patients following surgery. Conclusions– In this study, the prevalence of GER proven by 24 h ambulatory esophageal pH monitoring is 20% in pediatric patients with OATH. Following AT, GER resolved in 80% of cases and was reduced substantially in the remaining cases in the subset of patients with pre-operative GER. The symptoms of GERD based on parents' recall of child's previous symptoms may not accurately represent presence of GER. Our results suggest that OATH can result in GER due to increased negative intra-thoracic pressure as a result of breathing against an obstructed upper airway and hence, GER subsides following surgical removal of the obstructive pathology. To establish this concatenational association of OATH and GER, larger studies are mandated.

Respiratory cerebrospinal fluid flow is driven by the thoracic and lumbar spinal pressures.

Respiration plays a key role in the circulation of cerebrospinal fluid (CSF) around the central nervous system. During inspiration increased venous return from the cranium is believed to draw CSF rostrally. However, this mechanism does not explain why CSF has also been observed to move caudally during inspiration. We show that during inspiration decreased intrathoracic pressure draws venous blood from the cranium and lumbar spine towards the thorax. We also show that the abdominal pressure was associated with rostral CSF displacement. However, a caudal shift of cervical CSF was seen with low abdominal pressure and comparably negative intrathoracic pressures. These results suggest that the effects of epidural blood flow within the spinal canal need to be considered, as well as the cranial blood volume balance, to understand respiratory-related CSF flow. These results may prove useful for the treatment of CSF obstructive pathology and understanding the behaviour of intrathecal drug injections. It is accepted that during inspiration, cerebrospinal fluid (CSF) flows rostrally to compensate for decreased cranial blood volume, caused by venous drainage due to negative intrathoracic pressure. However, this mechanism does not explain observations of caudal CSF displacement during inspiration. Determining the drivers of respiratory CSF flow is crucial for understanding the pathophysiology of CSF flow disorders. To quantify the influence of respiration on CSF flow, real-time phase-contrast magnetic resonance imaging (MRI) was used to record CSF and blood flow, while healthy subjects (5:5 M:F, 25-50 years) performed either a brief expiratory or inspiratory effort between breaths. Transverse images were taken perpendicular to the spinal canal in the middle of the C3 and L2 vertebrae. The same manoeuvres were then performed after a nasogastric pressure catheter was used to measure the intrathoracic and abdominal pressures. During expiratory-type manoeuvres that elevated abdominal and intrathoracic pressures, epidural blood flow into the spinal canal increased and CSF was displaced rostrally. With inspiratory manoeuvres, the negative intrathoracic pressure drew venous blood from C3 and L2 towards the thoracic spinal canal, and cervical CSF was displaced both rostrally and caudally, despite the increased venous drainage. Regression analysis showed that rostral displacement of CSF at both C3 (adjusted R2 =0.53; P<0.001) and L2 (adjusted R2 =0.38; P<0.001) were associated with the abdominal pressure. However, with low abdominal pressure and comparably negative intrathoracic pressure, cervical CSF flowed caudally. These findings suggest that changes in both the cranial and spinal pressures need to be considered to understand respiratory CSF flow.