High Positive Pressure Ventilation Research Articles

Clinical characteristics of pneumothorax and pneumomediastinum in mechanical ventilated patients with coronavirus disease 2019: a case series

BackgroundPneumothorax (PTX) and pneumomediastinum (PM) have been reported as potential complications in patients with coronavirus disease 2019 (COVID-19); however, their risk factors and etiology remain unknown. Herein, we investigated the clinical characteristics of mechanically ventilated patients with COVID-19 with PTX or PM.MethodsWe examined patients with severe COVID-19 requiring mechanical ventilation who were admitted to the intensive care unit of a tertiary-level emergency medical center in Tokyo, Japan between April 1, 2020. and October 31, 2021. We collected and analyzed the clinical characteristics of the patients who presented with either PTX or PM during mechanical ventilation.ResultsDuring the study period, a total of 165 patients required mechanical ventilation, and 15 patients with PTX/PM during mechanical ventilation were selected. Three patients with obvious causes were excluded, and the remaining 12 patients were analyzed (7.3%). The mortality rate in these patients was as high as 50%, demonstrating the difficulty of treatment in the presence of PTX/PM. PTX/PM occurred 14.5 days after intubation. A peak pressure of > 30 cmH2O was only apparent in one patient, suggesting that high positive pressure ventilation may be less involved than mentioned in the literature. In addition, the inspiratory effort was not strong in our group of patients. (P0.1 was 2.1 cm H2O [1.0–3.8]).ConclusionVarious factors are associated with the development of PTX/PM in patients on mechanical ventilation for COVID-19. We did not find a strong correlation between PTM/PM and barotrauma or strong inspiratory efforts, which have been identified as potential causes in previous studies.

NONCARDIOGENIC NEGATIVE PRESSURE FLASH PULMONARY EDEMA IN A YOUNG ADULT PATIENT AFTER LARYNGOSPASM: A CASE REPORT

TOPIC: Respiratory Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Laryngospasm is a sudden involuntary muscular spasm of the vocal cords, it can lead to cardiac arrest due to hypoxia if not timely treated. Negative pressure flash pulmonary edema (NPPE) is a rare complication secondary to laryngospasm in adults after the acute treatment, which results from forceful inspiration against blocked airways and the resulting high negative pressure in alveoli, causing fluids to flux to the interstitial and alveolar spaces. Healthy individuals are more prone for NPPE due to the strength to induce higher intrathoracic negative pressure to challenge an obstruction. This case illustrates a young adult developed postoperative laryngospasm resulting in a flash NPPE. CASE PRESENTATION: A 40 year-old male, with a history of type 1 diabetes and recent mild COVID-19 Pneumonia was admitted for minor surgery. Pre-operative assessment concluded with ASA class 2, and moderate functional status. He has no history of anesthetic complications. Surgery was done under general anesthesia with a laryngeal mask (LMA). During Recovery after the LMA was removed, he started to desaturate, with audible stridor, cyanosis and retractions. High flow oxygen mask and IV Succinylcholine were given with no response. He was immediately intubated, ET tube suctioning showed large amounts of frothy pink secretions, his saturation had improved immediately to 100% with manual positive pressure ventilation. Sustained closure of the vocal cords was observed during intubation. However, his oxygen requirement didn't improve during the first day, and he failed a spontaneous breathing trial(SBT). Chest radiograph showed diffuse haziness suggestive of pulmonary edema. Chest CT showed pulmonary edema more significant in the dependent areas with atelectasis, it also showed diffuse ground glass opacities of recent COVID-19 pneumonia. He was started on parenteral furosemide, negative fluid balance of five liters was achieved in 24 hours. Surprisingly, his breathing effort was significantly improving with fluid elimination, oxygen requirements was weaned to minimum, passed SBT on CPAP mode, and later extubated. Patient was discharged with no evidence persistent airways pathology. DISCUSSION: Laryngospasm is less common in adults, usually it results from physical manipulation of the airways. Forceful inspiration against obstructed airways results in negative intrathoracic pressure above physiological limit, which disrupts the balance of hydrostatic pressures of alveoli, interstitium and the capillaries, leading to fluid accumulation in the alveolar space, it manifest clinically with desaturation, and diffuse opacities on imaging. High negative pressure increases the permeability as well, which drive the RBCs to extravasate and manifest as bloody mucous secretions. CONCLUSIONS: Fortunately, if NPPE gets timely recognized, patients respond magically to treatment with higher positive pressure ventilation and diuretics. REFERENCE #1: Bhattacharya M, Kallet RH, Ware LB, Matthay MA. Negative-Pressure Pulmonary Edema. Chest. 2016 Oct;150(4):927-933. doi: 10.1016/j.chest.2016.03.043. Epub 2016 Apr 8. PMID: 27063348. DISCLOSURES: No relevant relationships by Hasan Abuamsha, source=Web Response No relevant relationships by Hadeel Abuteer, source=Web Response No relevant relationships by Abdul Rahman Al Armashi, source=Web Response No relevant relationships by Isaac Alsallamin, source=Web Response No relevant relationships by Ameed Bawwab, source=Web Response No relevant relationships by Faris Hammad, source=Web Response No relevant relationships by Seshma Ramsawak, source=Web Response No relevant relationships by Francisco Somoza-Cano, source=Web Response

Clinical study on the treatment of acute pulmonary edema with high positive pressure ventilation at the end of expiratory

目的 评价高呼气末正压通气(PEEP)治疗各种突发性急性肺水肿的临床疗效.方法 50例突发性急性肺水肿患者,在药物治疗基础上,加用高PEEP(15～25 cm H2O)机械通气治疗,对比治疗前后呼吸(R)、心率(HR)、血压(BP)、氧饱和度(SaO2)等动脉血气指标及胸片变化,同时与50例常规药物治疗组进行对比.结果 经高PEEP机械通气治疗1～2 h后,48例呼吸频率减慢、心率减慢,血压明显下降,SaO2上升,血气指标好转,低氧血症明显改善,胸片示肺部阴影减少或消失,仅2例无效死亡,总有效率达96%.结论 高PEEP是治疗各种突发性急性肺水肿快速、有效的方法。

Airway Sealing Effect and Gastroesophageal Regurgitation of Laryngeal Mask Airway-Proseal in Laparoscopy

Background: The laryngeal mask airway Proseal (LMA-Proseal) is a renewed airway device with a modified cuff to improve the mask seal around the larynx. The classic LMA is known to have an incomplete mask seal during high positive pressure ventilation. Therefore, we examined whether the ventilation via a LMA-Proseal during laparoscopic surgery may be adequate and also observed the complications associated with a LMA-Proseal. Methods: Thirty four patients undergoing elective gynecological laparoscopies were studied. After the insertion of a LMA-Proseal, we measured the peak airway pressure, plateau airway pressure, oropharyngeal leakage pressure, and the leakage around the neck before and after intra-abdominal insufflation. After extubation, we observed the complications, including the gastroesophageal regurgitation using a methylene blue staining method. Results: The peak and plateau airway pressures after pneumoperitoneum increased significantly (P ＜ 0.05), compared with those before insufflation. However, the oropharyngeal leakage pressure was not changed and leakages around the neck were not observed. After extubation, a cuff stained with methylene blue occurred in 10 of 34 patients. Sore throat and dysphagia occurred in 8 and 4 of 34 patients, respectively. Conclusions: A LMA-Proseal during laparoscopic surgery permits adequate airway pressure, but does not protect the gastroesophageal regurgitation.

Effects of positive pressure ventilation and inspired oxygen on pulmonary vascular resistance and tissue oxygen delivery in neonatal pigs.

Management of pulmonary vascular resistance in neonates with congenital heart disease is important for stabilization before and after surgical interventions. Thus, we determined which combination of positive end-expiratory pressure ventilation and fraction of oxygen in the inspired air increases pulmonary vascular resistance without compromising delivery of oxygen to the tissue. Eight piglets were anesthetized, intubated and ventilated. Pulmonary flow and pulmonary arterial and left atrial pressures were monitored continuously. At all levels of inspired oxygen (1.00, 0.21 and 0.15), ventilation at a pressure of 15 cm of water increased pulmonary vascular resistance. At all levels of positive pressure ventilation, a fraction of 0.15 of inspired oxygen increased pulmonary vascular resistance. The combination of a ventilatory pressure of 15 cm of water and inspired oxygen of 1.00, or ventilatory pressure at 5 cm of water and oxygen delivery of 0.15, produced similar changes in pulmonary vascular resistance (19.1 +/- 2.8 vs. 20.0 +/- 3.8 mmHg/(L/min)) and cardiac output (0.78 +/- 0.07 vs. 0.93 +/- 0.10 L/min) but, the higher level of positive pressure plus 1.00 inspired oxygen gave a significantly higher arterial oxygen saturation (0.99 +/- 0.03 vs. 0.72 +/- 0.19%) and delivery of oxygen to the tissues (13.7 +/- 2.9 vs. 7.4 +/- 1.5 ml O2/min, p < 0.05). Thus, both high positive pressure ventilation and hypoxia increase pulmonary vascular resistance. Only high pressure ventilation plus high concentrations of inspired oxygen, however, increased pulmonary vascular resistance without compromising delivery of oxygen, suggesting that this combination is a superior means of increasing pulmonary vascular resistance.