Hyperoxia and Antioxidants for Myocardial Injury in Noncardiac Surgery: A 2 × 2 Factorial, Blinded, Randomized Clinical Trial.

BACKGROUND: Hyperoxia and oxidative stress may be associated with increased risk of myocardial injury. The authors hypothesized that a perioperative inspiratory oxygen fraction of 0.80 versus 0.30 would increase the degree of myocardial injury within the first 3 days of surgery, and that an antioxidant intervention would reduce degree of myocardial injury versus placebo. METHODS: A 2 × 2 factorial, randomized, blinded, multicenter trial enrolled patients older than 45 yr who had cardiovascular risk factors undergoing major noncardiac surgery. Factorial randomization allocated patients to one of two oxygen interventions from intubation and at 2 h after surgery, as well as antioxidant intervention or matching placebo. Antioxidants were 3 g IV vitamin C and 100 mg/kg N-acetylcysteine. The primary outcome was the degree of myocardial injury assessed by the area under the curve for high-sensitive troponin within the first 3 postoperative days. RESULTS: The authors randomized 600 participants from April 2018 to January 2020 and analyzed 576 patients for the primary outcome. Baseline and intraoperative characteristics did not differ between groups. The primary outcome was 35 ng · day/l (19 to 58) in the 80% oxygen group; 35 ng · day/l (17 to 56) in the 30% oxygen group; 35 ng · day/l (19 to 54) in the antioxidants group; and 33 ng · day/l (18 to 57) in the placebo group. The median difference between oxygen groups was 1.5 ng · day/l (95% CI, -2.5 to 5.3; P = 0.202) and -0.5 ng · day/l (95% CI, -4.5 to 3.0; P = 0.228) between antioxidant groups. Mortality at 30 days occurred in 9 of 576 patients (1.6%; odds ratio, 2.01 [95% CI, 0.50 to 8.1]; P = 0.329 for the 80% vs. 30% oxygen groups; and odds ratio, 0.79 [95% CI, 0.214 to 2.99]; P = 0.732 for the antioxidants vs. placebo groups). CONCLUSIONS: Perioperative interventions with high inspiratory oxygen fraction and antioxidants did not change the degree of myocardial injury within the first 3 days of surgery. This implies safety with 80% oxygen and no cardiovascular benefits of vitamin C and N-acetylcysteine in major noncardiac surgery.

A reduced gastric corpus microvascular blood flow during Ivor-Lewis esophagectomy detected by laser speckle contrast imaging technique.

BACKGROUND: Reduced microvascular blood flow is related to anastomotic insufficiency following esophagectomy, emphasizing a need for intraoperative monitoring of the microcirculation. This study evaluated if laser speckle contrast imaging (LSCI) was able to detect intraoperative changes in gastric microcirculation. METHODS: Gastric microcirculation was assessed prior to and after reconstruction of gastric continuity in 25 consecutive patients operated for adenocarcinoma with open Ivor-Lewis esophagectomy while hemodynamic variables were recorded. RESULTS: During upper laparotomy, microcirculation at the corpus decreased by 25% from baseline to mobilization of the stomach (p = .008) and decreased further (to a total decrease of 40%) following gastric pull to the thorax (p = .013). On the other hand, microcirculation at the antrum did not change significantly after gastric mobilization (p = .091). The decrease in corpus microcirculation took place unrelated to central cardiovascular variables. CONCLUSION: Using LSCI technique, we identified a reduced microcirculation at the corpus area during open Ivor-Lewis esophagectomy. LSCI provides an option for real-time assessment of gastric microcirculation and could form basis for intraoperative stabilization of the microcirculation.

Thoracic epidural analgesia reduces gastric microcirculation in the pig.

BACKGROUND: Thoracic epidural analgesia (TEA) is used for pain relief during and after abdominal surgery, but the effect of TEA on the splanchnic microcirculation remains debated. We evaluated whether TEA affects splanchnic microcirculation in the pig. METHODS: Splanchnic microcirculation was assessed in nine pigs prior to and 15 and 30 min after induction of TEA. Regional blood flow was assessed by neutron activated microspheres and changes in microcirculation by laser speckle contrast imaging (LSCI). RESULTS: As assessed by LSCI 15 min following TEA, gastric arteriolar flow decreased by 22 % at the antrum (p = 0.020) and by 19 % at the corpus (p = 0.029) of the stomach. In parallel, the microcirculation decreased by 19 % at the antrum (p = 0.015) and by 20 % at the corpus (p = 0.028). Reduced arteriolar flow and microcirculation at the antrum was confirmed by a reduction in microsphere assessed regional blood flow 30 min following induction of TEA (p = 0.048). These manifestations took place along with a drop in systolic blood pressure (p = 0.030), but with no significant change in mean arterial pressure, cardiac output, or heart rate. CONCLUSION: The results indicate that TEA may have an adverse effect on gastric arteriolar blood flow and microcirculation. LSCI is a non-touch technique and displays changes in blood flow in real-time and may be important for further evaluation of the concern regarding the effect of thoracic epidural anesthesia on gastric microcirculation in humans. TRIAL REGISTRATIONS: Not applicable, non-human study.

Evaluation of Gastric Microcirculation by Laser Speckle Contrast Imaging During Esophagectomy.

BACKGROUND: Thoracic epidural anesthesia (TEA) may provoke hypotension, and that, as well as the use of vasopressors and the surgical technique, could affect splanchnic microcirculation, in which the surgical target organ is of particular interest. This study used laser speckle contrast imaging (LSCI) to monitor gastric microcirculation during esophagectomy. STUDY DESIGN: Forty-five patients undergoing open esophagectomy were randomized to primary activation (EA; 25 patients) or no intraoperative activation (LA; 20 patients) of TEA. Phenylephrine managed intraoperative hypotension and gastric microcirculation was assessed at antrum and corpus area by LSCI. RESULTS: Antrum microcirculation (mean ± SD) was lower in the EA group at baseline (1,150 ± 189 laser speckle perfusion units [LSPU] vs LA group: 1,265 ± 163 LSPU; p = 0.036). In both groups, antrum microcirculation tended to decrease in response to anesthesia, TEA, and surgical procedure (LA: 1,265 ± 163 to 1,097 ± 184 LSPU, p = 0.021; EA: 1,150 ± 189 to 1,064 ± 177 LSPU, p = 0.093), with no difference between groups during the remaining laparotomy. Corpus microcirculation decreased in both groups from baseline to gastric pull-up in response to anesthesia, TEA, and surgery (LA: 1,081 ± 236 to 649 ± 165 LSPU, p < 0.001; EA: 1,011 ± 208 to 675 ± 178 LSPU, p < 0.001), but recovered after gastric continuity was re-established (EA to 795 ± 162 LSPU, p = 0.027; LA to 815 ± 166 LSPU, p = 0.014), with no significant differences between groups (p > 0.05). The EA group needed continued phenylephrine support to maintain blood pressure (216 ± 86 vs 58 ± 91 minutes; p < 0.001). CONCLUSIONS: During esophagectomy, gastric microcirculation can be followed in real-time by LSCI. Flow changes in the stomach seemed related more to surgery than to TEA/vasopressor support. Laser speckle contrast imaging could form basis for directing procedures to maintain the microcirculation.

[Heat stroke and burns resulting from use of sauna]. / Hedeslag og brandsår i forbindelse med saunaophold.

We describe a case of severe heat stroke resulting from exposure to extreme heat in a sauna for an unknown period of time. The patient sustained 20% 2nd degree burns. On arrival at the emergency department, the patient's temperature was 40.5 degrees C. At the critical care unit, the patient developed severe multi-organ failure and critical polyneuropathy. Severe heat stroke is a rare diagnosis in Denmark. The treatment is symptomatic and the prognosis is grave, especially in combination with severe burns.

[Resuscitation of severely hypothermic and multitraumatised female following long-term cardiac arrest]. / Dybt hypoterm og multitraumatiseret kvinde genoplivet efter langvarigt hjertestop.

We describe the case of a patient who was severely hypothermic after 45 minutes of submersion. The patient received about 90 minutes of basic and advanced life support before being connected to extra corporal heart lung assistance (ECHLA). The core temperature was 28.9 degrees C, plasma potassium was 3.7 mmol/l. The patient stabilized and was discharged without significant sequelae after four weeks. This case report describes the importance of basic life support in the hypothermic patient and the use of ECHLA.