Hypertonic saline reduces skeletal muscle injury and associated remote organ injury following ischemia reperfusion injury

Efficacy of non-surgical interventions for promoting improved functional outcomes following acute compartment syndrome: A systematic review

Background

Acute compartment syndrome (ACS) is a devastating complication which develops following a traumatic extremity injury that results in increased pressure within osteofascial compartments, thereby leading to ischemia, muscle and nerve necrosis, and creates a life-threatening condition if left untreated. Fasciotomy is the only available standard surgical intervention for ACS. Following fasciotomy the affected extremity is plagued by prolonged impairments in function. As such, an unmet clinical need exists for adjunct, non-surgical therapies which can facilitate accelerated functional recovery following ACS. Thus, the purpose of this systematic review was to examine the state of the literature for non-surgical interventions that aim to improve muscle contractile functional recovery of the affected limb following ACS.

Methods

English language manuscripts which evaluated non-surgical interventions for ACS, namely those which evaluated the function of the affected extremity, were identified as per PRISMA protocols via searches within three databases from inception to February 2022. Qualitative narrative data synthesis was performed including: study characteristics, type of interventions, quality, and outcomes. Risk of bias (RoB) was assessed using the Systematic Review Centre for Laboratory Animal Experimentation’s (SYRCLE) RoB tool and reported level of evidence for each article.

Results

Upon review of all initially identified reports, 29 studies were found to be eligible and included. 23 distinct non-surgical interventions were found to facilitate improved muscle contractile function following ACS. Out of 29 studies, 15 studies which evaluated chemical and biological interventions, showed large effect sizes for muscle function improvement.

Conclusions

This systematic review demonstrated that the majority of identified non-surgical interventions facilitated an improvement in muscle contractile function following pathological conditions of ACS.

Comparison of Ischemic Preconditioning and Systemic Piracetam for Prevention of Ischemia-Reperfusion Injury in Musculocutaneous Flaps

BACKGROUND

 Ischemia-reperfusion injury plays an important role in flap failure. Ischemic preconditioning technique is the only proven method for preventing ischemia-reperfusion injury, but it is not used widely in daily practice because of difficulties such as prolonging the operation time, need for surgical experience, and increasing the risk of complications. This study has been performed with the assumption that piracetam may be a simple and inexpensive alternative to the preconditioning technique due to its antioxidant, antiaggregant, rheological, anti-inflammatory, antiapoptotic, cytoprotective, and immune modulating effects.

METHODS

 Thirty-two rats were divided into four groups and latissimus dorsi musculocutaneous flaps were raised. No extra procedure was applied, and no treatment was given to the control group. Four hours of ischemia was created by clamping the thoracodorsal pedicle in the second group. The animals in the third group were treated with 10 minutes of ischemia and reperfusion periods as a preconditioning procedure before the 4 hours of ischemia. Animals in the fourth group received systemic piracetam 30 minutes before and 6 days after reperfusion. Nitric oxide and myeloperoxidase levels in serum and tissue, acute inflammatory cell response, and vascular proliferation in tissue were examined at the postoperative 24th hour and 10th day.

RESULTS

 Myeloperoxidase activity in both preconditioning and piracetam groups, was significantly lower than the ischemia-reperfusion group. Acute inflammatory cell response was similarly decreased in both preconditioning and piracetam groups compared with ischemia-reperfusion group. Tissue measurements of nitric oxide were also significantly higher in both preconditioning and piracetam groups than in the ischemia-reperfusion group. However, vascular proliferation increased in the preconditioning group, while it did not show any significant change in the piracetam group.

CONCLUSION

 This study shows that systemic piracetam treatment provides protection against ischemia-reperfusion injury in musculocutaneous flaps and can offer a simple and inexpensive alternative to the preconditioning technique.

Surgical embolectomy in a cat with cardiogenic aortic thromboembolism

A seven-year-old, spayed female, domestic longhair cat was referred for management of a sudden aortic thromboembolism (ATE). Echocardiography showed hypertrophic cardiomyopathy with severe left atrial enlargement. Ultrasonography of the abdominal aorta confirmed a large thrombus at the level of the aortic trifurcation, involving both iliac arteries. Considering the recent onset and bilateral involvement of the iliac arteries, the cat underwent emergent surgical embolectomy (SE) of the aortoiliac embolus. A standard caudal celiotomy was performed and the abdominal aorta was identified. Vessel loops with tourniquets were placed around the abdominal aorta proximal to the thrombus and on both iliac arteries distal to the thrombus. A full-thickness incision was made in the ventral surface of the aorta. The aortic thromboembolus was removed. The trifurcation was subsequently flushed with sterile saline. The SE resulted in a good outcome, with both clinical and ultrasound signs of complete reperfusion of the rear limbs within a few hours. Long-term treatment included antiplatelet drugs, furosemide and benazepril. Eighteen months after surgery, the cat was free of clinical signs, without recurrence of ATE or congestive heart failure. Based on the present case, SE could be considered as a feasible alternative to traditional conservative treatment in cats with a very recent onset of bilateral ATE.

Fatal early peripheral post-reperfusion syndrome and the role of cutaneous signs

The purpose of this report is to present the case of a 75-year-old male affected by right common femoral artery and abdominal aortic aneurysms. His clinical history was also characterised by post-ischaemic cardiomyopathy, arterial hypertension, chronic respiratory disease and peripheral arterial disease. We performed two surgical procedures: right femoral aneurysmectomy and femoro-femoral bypass and subsequently a femoro-femoral crossover bypass plus right femoro-popliteal bypass below the knee. The second operation became necessary in order to treat acute occlusion of the right iliac-femoral arterial axis. The patient developed a progressive and aggressive lower limb post-perfusion syndrome associated to frank peripheral oedema, myocardial stunning, reperfusion arrhythmias, renal failure and respiratory distress. Cutaneous alterations (oedema of the leg, mottled skin and cyanosis of the foot) were more specific compared with Doppler ultrasound that showed the presence of adequate blood flow in the early phase. On the basis of this experience and of pertinent literature, this study represents a challenge for the understanding of the exact mechanism of origin and progression of post-reperfusion syndrome.

Reperfusion strategies in the management of extremity vascular injury with ischaemia

BACKGROUND

Extremity injury with ischaemia is the most common pattern of vascular trauma and is a challenge for surgeons who must make decisions about the timing and mechanism of limb reperfusion. In modern military conflicts, effective use of limb tourniquets and rapid transport of the injured have increased the number of casualties who reach a medical service with potentially survivable vascular trauma. This report provides a review of extremity ischaemia and reperfusion following vascular trauma.

METHODS

A review was undertaken of extremity vascular injury with ischaemia, including a focus on adjuncts aimed at reducing reperfusion injury and improving neuromuscular recovery and limb salvage.

RESULTS

Findings from basic and clinical research support the need to restore perfusion to an ischaemic limb as soon as possible in order to achieve optimal neuromuscular recovery. Large-animal studies demonstrate that haemorrhagic shock worsens the impact of ischaemia on the neuromuscular structures of the limb and reduces the ischaemic threshold to as little as 1 h. Surgical adjuncts such as vascular shunts, fasciotomy, regional limb cooling and ischaemic conditioning may reduce the severity of ischaemic injury. Medical therapies have also been described including hypertonic saline, statins and ethyl pyruvate, which reduce the inflammatory response following limb reperfusion.

CONCLUSION

Contemporary translational research refutes a casual approach to extremity vascular injury with ischaemia, instead emphasizing expedited reperfusion. Surgical and medical adjuncts exist to expedite reperfusion and mitigate reperfusion injury. Additional research and development of these adjuncts is necessary to improve quality or functional limb salvage after vascular trauma.

The protective efficacy of magnolol in hind limb ischemia-reperfusion injury

We investigated the protective effects of magnolol, an active antioxidant and free radical scavenger extracted from Magnolia officinalis, in a hind limb ischemic-reperfusion animal model. Adult male Sprague-Dawley rats were subjected to hind limb ischemic insult for 2 hours and were intravenously treated with magnolol at 0.01 mg/kg (n=8), 0.3 mg/kg (n=8) mg/kg or 1 mg/kg (n=8) mg/kg, or vehicle (n=8). At 24 h post-insult, the levels of nitrite/nitrate (NOX), malondialdehyde (MDA) and myeloperoxidase (MPO), as well as the degree of muscle damage, were assessed. Relative to controls, animals treated with magnolol (0.3 and 1 mg/kg) had attenuated muscular inflammation, edema and damage. Magnolol (0.3-1 mg/kg) also effectively reduced postischemic rises in the MDA, NOx and MPO levels (p<0.05, respectively). Magnolol administrated at 0.01 mg/kg, however, failed to protect against the ischemic-perfusion limb injury. In addition, magnolol (0.01-1 mg/kg) did not affect local muscular blood reperfusion or other physiological parameters, including hematocrit, glucose, arterial blood gases and mean arterial blood pressure. Thus, intravenous administration with magnolol at 0.3-1 mg/kg protects against ischemic limb damage in rats. This cytoprotection may be attributed to its antioxidant, anti-nitrosative and anti-inflammatory actions.