scholarly journals Computed tomographic assessment of lung aeration at different positive end-expiratory pressures in a porcine model of intra-abdominal hypertension and lung injury

2020 ◽  
Author(s):  
Adrian Regli ◽  
Siavash Ahmadi-Noorbakhsh ◽  
Gabrielle Christine Mask ◽  
David Joseph Reese ◽  
Peter Herrmann ◽  
...  
Keyword(s):  
Lung Injury ◽  
Peep Level ◽  
Large Animal Model ◽  
Arterial Oxygen ◽  
Abdominal Pressure ◽  
High Peep ◽  
Large Animal ◽  
Computed Tomographic ◽  
Abdominal Hypertension ◽  
The Impact

Abstract Background Intra-abdominal hypertension (IAH) is common in critically ill patients and is associated with increased morbidity and mortality. High positive end-expiratory pressures (PEEP) can reverse lung volume and oxygenation decline caused by IAH in the setting of injured lungs. The impact of high PEEP levels on alveolar overdistension in IAH and lung injury is unknown. We aimed to define an optimal PEEP range during IAH and lung injury that would be high enough to reduce atelectasis formation while low enough to minimize alveolar overdistention. Methods Five anesthetized pigs received standardized anesthesia and mechanical ventilation. Peritoneal insufflation of air was used to generate intra-abdominal pressure of 27cmH2O (20 mmHg). Lung injury was created by intravenous oleic acid. PEEP levels of 5, 12, 17, 22, and 27cmH2O were applied. We performed computed tomography and measured arterial oxygen levels, respiratory mechanics, and cardiac output 5 min after each new PEEP level. The proportion of overdistended, normally aerated, poorly aerated, and non-aerated atelectatic lung tissue was calculated based on Hounsfield units. Results PEEP decreased poorly aerated and atelectatic lung whilst increasing normally aerated lung. Overdistension increased with each incremental increase in applied PEEP. Conclusions Our findings in a large animal model suggest that an optimal PEEP level which maximally recruits atelectatic lung without causing overdistension or hemodynamic compromise may not exist.

scholarly journals Computed tomographic assessment of lung aeration at different positive end-expiratory pressures in a porcine model of intra-abdominal hypertension and lung injury

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Adrian Regli ◽  
Siavash Ahmadi-Noorbakhsh ◽  
Gabrielle Christine Musk ◽  
David Joseph Reese ◽  
Peter Herrmann ◽  
...  
Keyword(s):  
Lung Injury ◽  
Respiratory Mechanics ◽  
Peep Level ◽  
Large Animal Model ◽  
Arterial Oxygen ◽  
Abdominal Pressure ◽  
Large Animal ◽  
Computed Tomographic ◽  
Abdominal Hypertension ◽  
Alveolar Overdistension

Abstract Background Intra-abdominal hypertension (IAH) is common in critically ill patients and is associated with increased morbidity and mortality. High positive end-expiratory pressures (PEEP) can reverse lung volume and oxygenation decline caused by IAH, but its impact on alveolar overdistension is less clear. We aimed to find a PEEP range that would be high enough to reduce atelectasis, while low enough to minimize alveolar overdistention in the presence of IAH and lung injury. Methods Five anesthetized pigs received standardized anesthesia and mechanical ventilation. Peritoneal insufflation of air was used to generate intra-abdominal pressure of 27 cmH2O. Lung injury was created by intravenous oleic acid. PEEP levels of 5, 12, 17, 22, and 27 cmH2O were applied. We performed computed tomography and measured arterial oxygen levels, respiratory mechanics, and cardiac output 5 min after each new PEEP level. The proportion of overdistended, normally aerated, poorly aerated, and non-aerated atelectatic lung tissue was calculated based on Hounsfield units. Results PEEP decreased the proportion of poorly aerated and atelectatic lung, while increasing normally aerated lung. Overdistension increased with each incremental increase in applied PEEP. “Best PEEP” (respiratory mechanics or oxygenation) was higher than the “optimal CT inflation PEEP range” (difference between lower inflection points of atelectatic and overdistended lung) in healthy and injured lungs. Conclusions Our findings in a large animal model suggest that titrating a PEEP to respiratory mechanics or oxygenation in the presence of IAH is associated with increased alveolar overdistension.

Endotracheal suctioning: ventilator vs manual delivery of hyperoxygenation breaths

1996 ◽  
Vol 5 (3) ◽  
pp. 192-197 ◽  
Author(s):  
MJ Grap ◽  
C Glass ◽  
M Corley ◽  
T Parks
Keyword(s):  
Clinical Practice ◽  
Lung Injury ◽  
Arterial Pressure ◽  
Oxygen Saturation ◽  
Arterial Oxygen ◽  
Suction Catheter ◽  
Endotracheal Suctioning ◽  
Arterial Blood ◽  
Before And After ◽  
The Impact

BACKGROUND: Despite a large number of studies on endotracheal suctioning, there is little data on the impact of clinically practical hyperoxygenation techniques on physiologic parameters in critically ill patients. OBJECTIVE: To compare the manual and mechanical delivery of hyperoxygenation before and after endotracheal suctioning using methods commonly employed in clinical practice. METHODS: A quasi-experimental design was used, with twenty-nine ventilated patients with a lung injury index of 1.54 (mild-moderate lung injury). Three breaths were given before and after each of two suction catheter passes using both the manual resuscitation bag and the ventilator. Arterial pressure, capillary oxygen saturation, heart rate, and cardiac rhythm were monitored for 1 minute prior to the intervention to obtain a baseline, continuously throughout the procedure, and for 3 minutes afterward. Arterial blood gases were collected immediately prior to the suctioning intervention, immediately after, and at 30, 60, 120, and 180 seconds after the intervention. Data were analyzed with repeated measures analysis of variance. RESULTS: Arterial oxygen partial pressures were significantly higher using the ventilator method. Peak inspiratory pressures during hyperoxygenation were significantly higher with the manual resuscitation bag method. Significant increases were observed in mean arterial pressure during and after suctioning, with both delivery methods, with no difference between methods. Maximal increases in arterial oxygen partial pressure and arterial oxygen saturation occurred 30 seconds after hyperoxygenation, falling to baseline values at 3 minutes for both methods. CONCLUSION: Using techniques currently employed in clinical practice, these findings support the use of the patient's ventilator for hyperoxygenation during suctioning.

scholarly journals Autoregulation assessment by direct visualisation of pial arterial blood flow in the piglet brain

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. P. Klein ◽  
V. De Sloovere ◽  
G. Meyfroidt ◽  
B. Depreitere
Keyword(s):  
Blood Flow ◽  
Brain Injury ◽  
Therapeutic Interventions ◽  
Arterial Blood Flow ◽  
Large Animal Model ◽  
Large Animal ◽  
Main Site ◽  
Cranial Window ◽  
Arterial Blood ◽  
The Impact

Abstract Impairment of cerebrovascular autoregulation (CAR) is common after brain injury, although the pathophysiology remains elusive. The mechanisms of vascular dysregulation, their impact on brain function, and potential therapeutic implications are still incompletely understood. Clinical assessment of CAR remains challenging. Observational studies suggest that CAR impairment is associated with worse outcomes, and that optimization of cerebral blood flow (CBF) by individual arterial blood pressure (ABP) targets could potentially improve outcome. We present a porcine closed cranial window model that measures the hemodynamic response of pial arterioles, the main site of CBF control, based on changes in their diameter and red blood cell velocity. This quantitative direct CAR assessment is compared to laser Doppler flow (LDF). CAR breakpoints are determined by segmented regression analysis and validated using LDF and brain tissue oxygen pressure. Using a standardized cortical impact, CAR impairment in traumatic brain injury can be studied using our method of combining pial arteriolar diameter and RBC velocity to quantify RBC flux in a large animal model. The model has numerous potential applications to investigate CAR physiology and pathophysiology of CAR impairment after brain injury, the impact of therapeutic interventions, drugs, and other confounders, or to develop personalized ABP management strategies.

scholarly journals Ex VivoFluorescence Molecular Tomography of the Spine

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Monish Pimpalkhare ◽  
Jin Chen ◽  
Vivek Venugopal ◽  
Xavier Intes
Keyword(s):  
Ex Vivo ◽  
Imaging Study ◽  
Intervertebral Disk ◽  
Large Animal Model ◽  
Data Sets ◽  
Large Animal ◽  
Wide Field ◽  
Accurate Localization ◽  
Quantification Accuracy ◽  
The Impact

We investigated the potential of fluorescence molecular tomography to imageex vivosamples collected from a large animal model, in this case, a dog spine. Wide-field time-gated fluorescence tomography was employed to assess the impact of multiview acquisition, data type, and intrinsic optical properties on the localization and quantification accuracy in imaging a fluorescent inclusion in the intervertebral disk. As expected, the TG data sets, when combining early and late gates, provide significantly better performances than the CW data sets in terms of localization and quantification. Moreover, the use of multiview imaging protocols led to more accurate localization. Additionally, the incorporation of the heterogeneous nature of the tissue in the model to compute the Jacobians led to improved imaging performances. This preliminary imaging study provides a proof of concept of the feasibility of quantitatively imaging complexex vivosamples nondestructively and with short acquisition times. This work is the first step towards employing optical molecular imaging of the spine to detect and characterize disc degeneration based on targeted fluorescent probes.

scholarly journals Effect of intra-abdominal hypertension on the strength of the postoperative scar of a laparotomic wound

2020 ◽  
Vol 24 (2) ◽  
pp. 223-226
Author(s):  
I. K. Morar
Keyword(s):  
Mechanical Strength ◽  
Negative Impact ◽  
Abdominal Cavity ◽  
Study Groups ◽  
Laboratory Animals ◽  
Abdominal Pressure ◽  
Abdominal Hypertension ◽  
Laparotomy Wound ◽  
The Impact ◽  
Postoperative Scar

Annotation. One of the main factors of postoperative eventration is intra-abdominal hypertension, which occurs in various surgical pathologies of the abdominal cavity. Despite the presence of a large number of scientific papers on the negative effect of intra-abdominal hypertension on the morphological state of granulation tissue in the area of the laparotomy wound, there are no publications on the impact on the strength of the postoperative scar. Therefore, the study aimed to investigate in an experiment on small laboratory animals the effect of intra-abdominal hypertension on the mechanical strength of the postoperative scar of a laparotomy wound. The experiment was performed on 120 laboratory rats, which underwent a median laparotomy and brought together the edges of the musculoaponeurotic layer of the anterior abdominal wall with simple nodal sutures. The main group consisted of 72 animals who developed intra-abdominal hypertension by inserting a container (condom) with a certain amount of Furacilin into the abdominal cavity. The comparison group consisted of 48 animals who had an empty condom inserted into the abdominal cavity after laparotomy. The mechanical strength of the postoperative scar of the laparotomy wound was determined by the method of G. V. Petrovich (2010) on the 1st, 3rd, and 5th day after the creation of intra-abdominal hypertension, by measuring the level of intra-abdominal pressure at the time of rupture of the postoperative scar of the laparotomy wound. Statistical analysis of the results was performed using Microsoft Excel spreadsheets and a package of statistical processing software PAST. Differences between study groups were determined using Mann-Whitney criteria. The results of the study indicate that the created intra-abdominal hypertension leads to a decrease in the mechanical strength of the postoperative scar of the laparotomy wound. The degree of the negative impact of intra-abdominal hypertension on the strength of the postoperative scar is inversely proportional to the level of intra-abdominal pressure.

scholarly journals Correlation of intra-abdominal pressure with the outcome of perforation peritonitis

2017 ◽  
Vol 4 (5) ◽  
pp. 1584
Author(s):  
Saurabh Agrawal ◽  
Tarun Chaudhary ◽  
Shantanu Kumar Sahu
Keyword(s):  
Surgical Site Infection ◽  
Pearson Correlation ◽  
Wound Dehiscence ◽  
Bladder Pressure ◽  
Abdominal Pressure ◽  
Emergency Laparotomy ◽  
Site Infection ◽  
Abdominal Hypertension ◽  
Perforation Peritonitis ◽  
The Impact

Background: A progressive increase in intra-abdominal pressure (IAP) may cause abdominal compartment syndrome (ACS) with organ dysfunction. Studies have documented the impact of Intra-abdominal hypertension (IAH) on virtually every organ. However, it remains strangely underdiagnosed. Present study was aimed to correlate Intra- abdominal pressure with the outcome in perforation peritonitis patients.Methods: This study was done on 50 patients with perforation peritonitis and patients undergoing intervention in the form of either emergency laparotomy or drain placement. The abdominal pressures were indirectly determined by measuring urinary bladder pressure with a Foley's catheter. Pearson correlation was used to see relation between intra-abdominal pressure and outcome of peritonitis.Results: Mean intra-abdominal pressure during time of presentation to the hospital was 26.7±3.2cm H2O. Among various morbidities following operation, surgical site infection was most common (38%) followed by wound dehiscence (24%). There was weak linear correlation between intra-abdominal pressure and factors determining morbidity such as surgical site infection, wound dehiscence, burst abdomen, prolonged ileus, ARDS and ARF. However, this was not statistically significant.Conclusions: There is weak correlation of various co morbidities with increased intra-abdominal pressure in patients with perforation peritonitis which was not significant statistically.

scholarly journals Long-term endoscopic submucosal dissection with postoperative lung injury: a case report

BMC Surgery ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qian-Mei Zhu ◽  
Hong Tu ◽  
Bing Hu ◽  
Xiao Wang
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Endoscopic Submucosal Dissection ◽  
Operation Time ◽  
Gastric Tumor ◽  
Greater Omentum ◽  
Invasive Technique ◽  
Submucosal Dissection ◽  
Abdominal Hypertension ◽  
The Impact

Abstract Background Endoscopic submucosal dissection (ESD) has been recognized as a safe and minimally invasive technique for the removal of early gastric cancer. Here, we describe a case of extended-duration ESD for a gastric tumor associated with intraoperative perforation and bleeding. Unfortunately, the patient developed acute lung injury (ALI) after the operation. Case presentation: A 72-year-old woman received ESD for a gastric tumor under general anesthesia. Preoperatively, endoscopic ultrasonography (EUS) showed a 3.1 × 3.5 cm hypoechoic, well-defined mass at the junction of the antrum and body of the stomach on the greater curvature, originating in the muscularis propria layer. During the ESD procedure, when the submucosal mass was stripped, it was found to be closely adhered to the muscular layer and serosa layer, and a full-thickness incision was performed. The abdominal cavity was gradually filled with carbon dioxide gas, and abdominal puncture was performed to reduce intra-abdominal hypertension (IAH). Because the mass adhered to the greater omentum and there was more bleeding during the operation, a long duration of hemostasis and suturing of the wound was required. The whole operation lasted nearly 9 h, and total blood loss was 800 ml. After surgery, acute lung injury was suspected, and the patient was sent to the intensive care unit (ICU) for further treatment. Conclusions The operation time of ESD and IAH caused by perforation are closely related to a poor prognosis. We should pay attention to the impact of operation time on patients and improve awareness regarding protecting important organ functions.

Sign in / Sign up

Export Citation Format

Share Document