The Effects of Chronically Increased Intra-abdominal Pressure on the Rabbit Diaphragm

Respiratory physiology in pregnancy and assessment of pulmonary function

A progressive chest wall adaptation occurs during pregnancy driven by the hormones and the expanding uterus. The effect of the former is more prevalent in the first weeks of pregnancy, while the latter is more evident in the last trimester. The combination of the hormonal-induced joint loosening together with the progressively enlarging uterus produces changes in the whole chest wall geometry, with the thoracic alterations being the most fundamental. The ribcage changes in size, but not in volume, secondary to an upward bucket handle shift centred in the xiphoidal process so that the lung is not restricted. A virtuous cycle of stretching and muscle conditioning seems to be established between the enlarging uterus, the diaphragm, and the abdominal muscles to prepare these muscles for the expulsive phase. From the respiratory point of view, the supine position seems to hinder the action of the abdominal muscles during forced expiration at the end of pregnancy.

Diaphragmatic dysfunction in sepsis due to severe acute pancreatitis complicated by intra-abdominal hypertension

Objective

This study aimed to examine the mechanism of diaphragmatic dysfunction in sepsis due to severe acute pancreatitis (SAP) with intra-abdominal hypertension (IAH) in a rat model.

Methods

The rats were assigned at random to four groups: (1) control (n = 5), (2) SAP (n = 5), (3) SAP+IAH (n = 5), and (4) SAP+IAH+SS-31 (n = 5). Length and force output of the diaphragm were analysed in vivo. Histopathological examinations were performed by haematoxylin–eosin. Oxidative stress levels related to protease in diaphragmatic mitochondria were detected with a colorimetric technique.

Results

In the septic rat model due to SAP complicated by IAH, myofibres were increased. Muscle contractile function was significantly lower in the SAP+IAH group compared with the SAP and control groups. Glutathione peroxidase and superoxide dismutase levels were significantly lower and malondialdehyde levels were higher in the SAP and SAP+IAH groups compared with the control group. Notably, SS-31 could reverse atrophy of myofibres in SAP+IAH rats, as well as contractile dysfunction and mitochondrial dysfunction in the diaphragm.

Conclusions

Diaphragmatic structure and biomechanics are altered in septic rats due to SAP and IAH. This finding is mainly due to an increase in release of mitochondrial reactive oxygen species.

Preliminary Evaluation of the Viability of Peritoneal Drainage Catheters Implanted in Rats for Extended Durations

Purpose/Aim: In developing a novel peritoneal oxygenation therapy, catheters implanted into the peritoneal cavity became obstructed with omental tissue and prevented the infusion and removal of fluid from the peritoneal cavity. The obstruction of peritoneal catheters is a significant failure in researching various peritoneal treatments as further fluid administration is no longer possible. The purpose of this preliminary study was to determine the most effective catheter design for infusion and removal of fluid into the peritoneal cavity of rats. Materials and Methods: Four types of catheters were tested including the Jackson-Pratt, round fluted drain, flat fluted drain, and an original design. Three of each catheter type were surgically placed into the peritoneal cavity of rats (n = 12). In order to test the efficacy of each catheter, saline was infused and extracted twice daily. Catheters were scored on a weighted scale based on the amount of time they remained patent, the subjective force needed for extraction/infusion, and the amount of saline removed. Results: The round and flat fluted drain catheters remained patent for the full duration of the study (12 days) compared to the other models which failed after 7 days. These catheters also yielded a high average for extracted saline volume and an easy extraction/infusion. Conclusions: The round and flat fluted drain catheters were recognized as viable options to be used in rats for peritoneal drain studies of up to 12 days.

Effects of bariatric surgery on inspiratory muscle strength

Background

The respiratory function is affected by obesity due to an increased deposition of fat on the chest wall. The objective of this study was to investigate the strength of the inspiratory respiratory muscles of obese individuals and the possible influence of bariatric surgery on it by measuring the maximum inspiratory pressure (MIP).

Methods

Patients referred to a bariatric centre between the 3rd of October 2011 and the 3rd of May 2012 were screened preoperatively by a multidisciplinary team. Their MIP was measured at screening and 3, 6 and 9 months postoperative. In case of a preoperative MIP lower than 70% of predicted pressure training was provided supervised by a physiotherapist.

Results

The mean age of 124 included patients was 42.9 ± 11.0 years and mean BMI was 43.1 ± 5.2 kg/m². The mean predicted MIP preoperatively was 127 ± 31 in cm H₂O and the mean measured MIP was 102 ± 24 in cm H₂O. Three patients (2.4%) received training. Three months after surgery the MIP was 76 ± 26 cm H₂O, after 6 months 82 ± 28 cm H₂O and after 9 months 86 ± 28 cm H₂O. All postoperative measurements were significant lower than preoperatively (P < 0.05). The only influencing factor for the preoperative MIP was age (p = 0.014).

Conclusion

The preoperative MIP values were significantly lower than the predicted MIP values, probably due to altered respiratory mechanics.

Body mass index is associated with hospital mortality in critically ill patients: an observational cohort study

OBJECTIVE

Obesity is associated with a variety of diseases, which results in a decreased overall life expectancy. Nevertheless, some studies suggest that being overweight may reduce hospital mortality of certain patient groups, referred to as obesity paradox. Conflicting results for critically ill patients are reported. Therefore, we wished to investigate the association of body mass index and hospital mortality in critically ill patients.

DESIGN

Observational cohort study in Dutch critically ill patients.

SETTING

A dataset from the Dutch National Intensive Care Evaluation registry that includes patients admitted to Dutch ICUs was used.

PATIENTS

One hundred fifty-four thousand three hundred and eight ICU patients of teaching and nonteaching units in urban and nonurban hospitals.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We used logistic regression analysis, correcting for case mix (Simplified Acute Physiology Score II, age, gender, admission type, neoplasm, AIDS, hematologic malignancy, immunologic insufficiency, mechanical ventilation, and calendar year), to determine the relationship between body mass index and hospital mortality. Body mass index was included in the model as a continuous nonlinear covariate in a restricted regression spline transformation. To facilitate interpretation, adjusted odds ratios were calculated for the World Health Organization-based body mass index classes. Body mass index was found to be significantly associated with hospital mortality, with risks quickly increasing for underweight patients (body mass index < 18.5 kg/m). Obese and seriously obese patients, with a body mass index of 30-39.9 kg/m, had the lowest risk of death with an adjusted odds ratio of 0.86 (0.83-0.90).

CONCLUSIONS

This large observational database shows an inverse association between obesity and hospital mortality in critically ill patients that could not be explained by a variety of known confounders.

Body mass index is not associated with cytokine induction during experimental human endotoxemia

A higher body mass index (BMI) appears to be associated with lower mortality in critically ill patients, possibly explained by an altered innate immune response. However, the precise relationship between BMI and the innate immune response in humans in vivo is unknown. We investigated the relationship between BMI and the systemic cytokine response during experimental human endotoxemia. Endotoxemia was induced in 112 healthy male volunteers by intravenous administration of 2 ng/kg Escherichia coli endotoxin. Plasma concentrations of TNF-α, IL-6, IL-10 and IL-1RA were serially determined. The relationship between BMI and the cytokine response, as well as body temperature, was investigated. The BMIs of the participants ranged from 18.3 to 33.6 kg/m2, (median: 22.7 kg/m2). All participants showed a marked increase in plasma cytokine levels [median (interquartile range)] peak levels: TNF-α 509 (353–673) pg/ml; IL-6 757 (522–1098) pg/ml; IL-10 271 (159–401) pg/ml; IL-1RA 4882 (3927–6025) pg/ml; and an increase in body temperature [1.8(1.4–2.2)℃] during endotoxemia. No significant correlations were found between BMI and levels of any of the cytokines or body temperature. No relationship between BMI and the cytokine response was found in healthy volunteers subjected to experimental endotoxemia. These data question the relationship between BMI and cytokine responses in critical illness.

Laparoscopic repair of secondary parahiatal hernia with incarceration of the stomach: a case report

Introduction

Parahiatal hernia is an extremely rare subtype of hiatal hernia, which in turn is a type of diaphragmatic hernia in adults, and only a few cases have been reported to date. We report the case of a patient who suffered from gastric incarceration through an anatomically separate diaphragmatic defect, immediately lateral to a structurally normal esophageal hiatus, that developed after treatment of a malignant mesothelioma.

Case presentation

A 70-year-old Japanese man, who had undergone treatment for a left malignant pleural mesothelioma a year ago at another hospital, was referred to our institution following a 4-day history of epigastric pain. Esophagogastroscopy demonstrated a normal esophagogastric junction, with remarkable stenosis and active gastric ulcer of the gastric body. Histopathological examination of the gastric biopsy specimen confirmed a gastric ulcer. Furthermore, computed tomography revealed a large fluid-filled structure in the retrocardiac space. On the basis of preoperative data, we decided to attempt laparoscopic repair for the gastric volvulus. During surgery, gastric and omental herniation was observed within a peritoneal lined defect immediately lateral to the esophageal hiatus. Dissection near the esophageal hiatus revealed a discrete extrahiatal defect 3cm in diameter immediately adjacent to the left crus of the diaphragm. The parahiatal defect was closed using interrupted nonabsorbable heavy suture. The patient’s postoperative course was uneventful, and anastomotic leakage was not observed at postoperative barium swallowing.

Conclusions

Although preoperative diagnosis of parahiatal hernia is difficult, a laparoscopic approach can be a useful therapeutic procedure not only for paraesophageal hernia but also for parahiatal hernia.