Intraluminal oxygen mitigates acute mesenteric ischaemia: a systematic review of methods and outcomes in animal studies.

BACKGROUND: Acute Mesenteric Ischaemic (AMI) is a rare condition with significant morbidity and mortality. Many causes of AMI exist, which usually begin with mucosal injury. Onset is insiduous and there is frequent diagnostic delay. Current treatments can only control established injury and prevent propagation, hence new interventions are needed. The prevention and treatment of AMI by intraluminal delivery of oxygen has yet to be investigated in the clinical setting. This article aims to systemically review experimental studies investigating this novel therapy. METHODS: Following the PRISMA guidelines, searches of PubMed and Ovid MEDLINE databases were performed up to June 2022. Two independent investigators extracted the data. RESULTS: There were 20 experimental studies, 16 of which used an occlusive ischaemia reperfusion model. Six different formulations were used to deliver intraluminal oxygen, with perflurocarbon being the most common. Studies consistently showed local and systemic benefits. Intraluminal oxygen therapy improved histological severity of mucosal injury in all studies when oxygen was delivered during the ischaemia phase, but could cause harm if given during the reperfusion phase. Improvement was also demonstrated in endpoints assessing intestinal function, biomarkers of intestinal damage, measures of systemic physiological derangement and mortality. CONCLUSION: Intraluminal oxygenation appears to be an effective treatment for AMI. There remain significant questions regarding optimal timing and delivery formulation before clinical translation of this treatment strategy.

Admission, management and outcomes of acute pancreatitis in intensive care.

BACKGROUND: A review of the management of acute pancreatitis (AP) at a tertiary intensive care unit (ICU) in Auckland, New Zealand, was published in 2004. This paper aims to update this series and identify changes in admission criteria, management and outcomes. METHODS: A retrospective review of patients admitted to the Department of Critical Care Medicine, Auckland City Hospital, with AP from 2003 to 2014 was undertaken and data compared with the previous study (1988-2001). RESULTS: Eighty-four patients (male 53, mean ± SD age = 56.9 ± 15 years) with 85 admissions to ICU from 2003 to 2014 were compared with 112 patients in the previous study. Maori were over-represented. Median duration of symptoms prior to admission to ICU decreased from 7 to 3 days. The proportion of total AP patients admitted to ICU halved and the mean Acute Physiology and Chronic Health Evaluation II score on admission decreased from mean 19.9 ± 8.2 SD to 15.4 ± 7.3 (P < 0.001). Two thirds of patients had persistent organ failure. The use of enteral feeding doubled from 46/112 (41%) to 71/85 (84%) (P < 0.001). The use of primary percutaneous drainage increased from 14/112 (13%) to 24/85 (28%) (P = 0.007). Rate of necrosectomy was similar (36/112 (32%) versus 20/85 (24%), P = 0.205), although minimally invasive necrosectomy was introduced. Overall hospital mortality decreased by 29% (P = 0.198). CONCLUSION: There have been changes to the admission criteria and management in line with evolving guidelines and, overall, outcomes have improved.

Mesenteric lymph: the bridge to future management of critical illness.

Toxic factors released from the intestine have been implicated in the pathophysiology of severe acute illness, including acute pancreatitis, trauma and hemorrhagic shock, and burns. Toxic factors in mesenteric lymph may induce an inflammatory systemic response while bypassing the portal circulation and liver. This paper reviews current knowledge of the anatomy, physiology and pathophysiology of mesenteric lymph and focuses on factors influencing its composition and flow, and potential therapeutic interventions. A search of the Ovid MEDLINE database up until the end of January 2006 yielded 1,761 relevant publications, the references of which were then searched manually to identify further related publications. A wide range of factors potentially affecting mesenteric lymph flow and composition were identified. Targeted interventions have been similarly broad, including medical therapy, nutritional support and surgery. Of the available surgical interventions, thoracic duct external drainage has been the most widely studied. This systematic review highlights significant gaps in our present understanding of the role of mesenteric lymph in health and disease. Further research is needed to identify factors responsible for the generation of biologically active mesenteric lymph, the role of agents modulating its flow and composition, the importance of intrinsic pump activity, the potential therapeutic role of lipophilic antioxidant agents, the comparative effects of low-fat enteral nutrition and standard enteral nutrition, and the therapeutic outcomes of thoracic duct ligation versus thoracic duct external drainage.

Can true monocular keratoconus occur?

Evidence increasingly supports keratoconus as an inherited, genetic disorder. If this is the case, it would be expected to express itself as a binocular condition even though variable expression of the gene may show differing levels in the two eyes. It is a common occurrence in specialist contact lens practices to see pseudo-monocular keratoconus, that is, an overt clinical level of the condition in one eye and forme fruste keratoconus in the other. The advent of videokeratoscopy has shown almost every case of apparent monocular keratoconus to be different expressions of the condition in the two eyes. Nevertheless, rare cases of the condition are seen that appear to be truly monocular. Such a case is presented in which the condition has been present for more than 23 years. The age of the subject makes the future onset of keratoconus highly unlikely and videokeratoscopy does not show the presence of forme fruste in the 'good' eye. There is no history of monocular eye rubbing. Pachymetry shows the normal eye to be well within the range of normal corneal thickness, while the keratoconus in the other eye is sufficiently advanced to warrant corneal grafting. Thus, it is a case of true monocular keratoconus and represents an extreme example of variable gene expression.

Stickler syndrome.

Stickler syndrome is a relatively rare condition (approximately 1 in 10,000), caused by a defective collagen gene and characterised by high myopia, high risk of retinal detachment and flattened facial features. An outline of the condition, its systemic and ocular manifestations and optometric management are described.