The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery

The Association between Two-Stage Tourniquet Application during Total Knee Replacement and Blood Loss: A Retrospective Cohort Study

Tourniquet use during total knee arthroplasty improves the surgical field, but is associated with several complications. The medical records of 506 patients who underwent elective total knee arthroplasty or total knee replacement from January 2017 to December 2020 were reviewed. A total of 331 patients who had undergone total knee arthroplasty were included. In the first half course group, the tourniquet was inflated with a pressure of 300 mmHg after manual banding before the incision and deflated after cement insertion. In the two-stage group, the tourniquet was inflated and deflated at the same stages of the procedure as in the first half course group. However, in this second group, the tourniquet was deflated for 15 min and then inflated again, and, finally, it was deflated after skin closure. The estimated blood loss, the number of patients who needed medications to control their blood pressure, and opioid usage at the post-anesthesia care unit were similar in both groups. The two-stage tourniquet technique was not related to reduced total blood loss in total knee arthroplasty.

Tourniquet-induced tissue hypoxia characterized by near-infrared spectroscopy during ankle surgery: an observational study

BACKGROUND

Pneumatic tourniquet inflation during extremity surgery leads to profound and prolonged tissue ischemia. Its effect on tissue oxygenation is inadequately studied.

METHODS

Patients undergoing elective ankle surgery with tourniquet application participated in this observational cohort study. Somatic and cerebral tissue oxygen saturation (SstO₂ and SctO₂) were monitored using tissue near-infrared spectroscopy. Oxygenation was monitored distally (SstO₂-distal) and proximally to the tourniquet, on the contralateral leg, and the forehead (a total of 4 tissue beds). Tissue oxygenation at different time points was compared. The magnitude, duration, and load (product of magnitude and duration) of tissue desaturation during tourniquet inflation were correlated with tissue resaturation and hypersaturation after tourniquet deflation.

RESULTS

Data of 26 patients were analyzed. The tourniquet inflation time was 120 ± 31 mins. Following a rapid desaturation from 77 ± 8% pre-inflation to 38 ± 20% 10 mins post-inflation, SstO₂-distal slowly and continuously desaturated and reach the nadir (16 ± 11%) toward the end of inflation. After deflation, SstO₂-distal rapidly resaturated from 16 ± 11% to 91 ± 5% (i.e., hypersaturation); SstO₂ monitored proximally to the tourniquet and on contralateral leg had significant but small desaturation (~ 2-3%, p <  0.001); in contrast, SctO₂ remained stable. The desaturation load had a significant correlation with resaturation magnitude (p <  0.001); while the desaturation duration had a significant correlation with hypersaturation magnitude (p = 0.04).

CONCLUSIONS

Tissue dys-oxygenation following tourniquet application can be reliably monitored using tissue oximetry. Its outcome significance remains to be determined.

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

Near-infrared spectroscopy (NIRS) is used to monitor regional cerebral oxygenation (rScO₂) during cardiac surgery but is less established during non-cardiac surgery. This systematic review aimed (i) to determine the non-cardiac surgical procedures that provoke a reduction in rScO₂ and (ii) to evaluate whether an intraoperative reduction in rScO₂ influences postoperative outcome. The PubMed and Embase database were searched from inception until April 30, 2013 and inclusion criteria were intraoperative NIRS determined rScO₂ in adult patients undergoing non-cardiac surgery. The type of surgery and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO₂ is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparoscopic surgery with the patient placed in anti-Tredelenburg's position. Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery (ICA) also cause pronounced cerebral desaturation. A >20% reduction in rScO₂ coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery, major orthopedic, and abdominal surgery the occurrence of postoperative cognitive dysfunction (POCD) might be related to intraoperative cerebral desaturation. In conclusion, certain non-cardiac surgical procedures is associated with an increased risk for the occurrence of rScO₂. Evidence for an association between cerebral desaturation and postoperative outcome parameters other than cognitive dysfunction needs to be established.

Acute pulmonary edema following inflation of arterial tourniquet

Arterial tourniquets are used as one of the methods for reducing blood loss and for allowing blood free surgical field. A 20-year-old, 45 kg healthy female with a sphere shaped pendunculated hemangioma in the popliteal fossa of her left lower limb was applied with arterial tourniquet after exsanguination. The procedure was performed under general anesthesia. Soon after exsanguination and tourniquet inflation, the patient developed pulmonary edema which subsided after deflating the tourniquet. The clinical evolution, treatment and pathophysiology of this complication are described.