Effects of the Prophylactic Use of Amiodarone Infusion to Prevent Postoperative Atrial Fibrillation after Cardiac Surgery

Postoperative atrial fibrillation（AF）is associated with significant morbidity after cardiac surgery. We examined the effects of a prophylactic postoperative amiodarone infusion to prevent postoperative AF. A prospective randomized study was performed in patients with a high risk of postoperative AF between March 2016 and March 2019. High risk of AF was defined as combined valve surgery, aortic valve replacement（age＞70）, or off-pump coronary bypass grafting（age＞65）. Forty-two patients were enrolled and randomly assigned to receive prophylactic amiodarone infusion（amiodarone group, n＝20）or saline infusion（control group, n＝22）. In the amiodarone group, amiodarone was infused intravenously for 48hr postoperatively（initially 125mg/10min, then 288mg/6hr, then maintenance of 1,040mg/42hr）. There were no significant differences between the two groups in age, sex, body height, body weight, surgical procedure, and perioperative use of beta blockers. The occurrence of sustained AF for＞1hr was significantly lower in the amiodarone group（30.0％）than in the control group（63.6％, p＝0.04）. The total duration of AF over one week was also significantly shorter in the amiodarone group（296.8±676.9min）than in the control group（921.4±1641.6min, p＝0.04）, as was the postoperative hospital stay（17.3±6.1 vs. 24.5±11.3 days, respectively, p＝0.01）. There were no major side effects with amiodarone infusion except for one case of bradycardia. These results show the prophylactic use of intravenous amiodarone infusion for the first 48hr of the postoperative period is a safe and effective treatment to prevent postoperative AF after cardiac surgery and to shorten the hospital stay

Atrophy of the abdominal wall muscles after extraperitoneal approach to the aorta

AbstractObjectiveWe retrospectively assessed computed tomography (CT) scans to determine degree of anterolateral abdominal muscle atrophy in patients who underwent infrarenal aortic repair with 2 kinds of incisions for the extraperitoneal approach.MethodsCT scans obtained before surgery and final scans obtained 2 to 100 months after surgery were assessed in 12 patients with paramedian incision (PM group) and 27 patients with flank incision (F group) who could be followed up at our hospital. We considered muscle thickness before surgery on the incision side to be 100% thickness (baseline value), and we calculated, by measuring the incision side after surgery, the corrected percent thickness (CPT%), which represents percentage of remaining muscle thickness that has escaped incision-induced atrophy. CT scans obtained at the level of the third (L3) and fifth (L5) lumbar vertebrae and the center of the sacrum (S) were selected for CPT% measurement.ResultsDuration from surgery to final CT scan was 2 to 65 months (mean ± SD, 34.33 ± 21.38 months) in PM group and 3 to 96 months (27.85 ± 20.74 months) in F group. In PM group, mean CPT% values of the rectus abdominis muscle were 55.83 ± 21.65% at L3, 35.50 ± 10.79% at L5, and 31.92 ± 11.00% at S; these values were statistically much smaller than baseline (P < .01). Mean CPT% values of the lateral abdominal muscles were not statistically different from baseline. In F group, mean CPT% values of the rectus abdominis muscle were 82.19 ± 23.15% at L5 and 64.41 ± 31.34% at S; these values were statistically smaller than baseline (P < .01). Mean CPT% values of the lateral abdominal muscles were 87.59 ± 22.30% at L3 and 84.59 ± 26.90% at L5; these values were statistically smaller than baseline (P < .05).ConclusionsParamedian incision induced severe rectus abdominis muscle atrophy. Although flank incision induced various degrees of atrophy in both muscles, some patients had no muscle atrophy. These data indicate that further anatomic investigation into the relation between flank incision and abdominal wall innervation may contribute to prevention of muscle atrophy after flank incision

Clinical Implications of Determining Individualized Positive End-Expiratory Pressure Using Electrical Impedance Tomography in Post-Cardiac Surgery Patients: A Prospective, Non-Randomized Interventional Study

Optimal positive end-expiratory pressure (PEEP) can induce sustained lung function improvement. This prospective, non-randomized interventional study aimed to investigate the effect of individualized PEEP determined using electrical impedance tomography (EIT) in post-cardiac surgery patients (n = 35). Decremental PEEP trials were performed from 20 to 4 cmH2O in steps of 2 cmH2O, guided by EIT. PEEP levels preventing ventilation loss in dependent lung regions (PEEPONLINE) were set. Ventilation distributions and oxygenation before the PEEP trial, and 5 min and 1 h after the PEEPONLINE setting were examined. Furthermore, we analyzed the saved impedance data offline to determine the PEEP levels that provided the best compromise between overdistended and collapsed lung (PEEPODCL). Ventilation distributions of dependent regions increased at 5 min after the PEEPONLINE setting compared with those before the PEEP trial (mean &plusmn; standard deviation, 41.3 &plusmn; 8.5% vs. 49.1 &plusmn; 9.3%; p &lt; 0.001), and were maintained at 1 h thereafter (48.7 &plusmn; 9.4%, p &lt; 0.001). Oxygenation also showed sustained improvement. Rescue oxygen therapy (high-flow nasal cannula, noninvasive ventilation) after extubation was less frequent in patients with PEEPONLINE &ge; PEEPODCL than in those with PEEPONLINE &lt; PEEPODCL (1/19 vs. 6/16; p = 0.018). EIT-guided individualized PEEP stabilized the improvement in ventilation distribution and oxygenation. Individual PEEP varies with EIT measures, and may differentially affect oxygenation after cardiac surgery

短期間のうちにコルチゾールの自律的分泌能が明確となった副腎偶発腫瘍の一例

A 57-year-old woman was admitted to the hospital for the further evaluation of a left adrenal incidentaloma measuring 45 mm x 33 mm. She had no signs of the clinical manifestation of hypercortisolism. An endocrine evaluation revealed that her ACTH level was normal and cortisol values were almost normal pattern excluding the value at 9 PM slightly rising, however, the cortisol was not completely suppressed by the overnight administration of 1 mg dexamethasone. These findings indicated that subtle abnormalities of the hypothalamo-pituitary-adrenal axis were present in this case. After 3 months, surprisingly, the ACTH was suppressed to low levels. Further hormonal investigations revealed that the cortisol level was normal but had an abnormal diurnal rhythm and was not suppressed completely by a 1 mg or an 8 mg overnight dexamethasone dose. Adrenal scintigraphy revealed positive uptake in the left adrenal tumor with no uptake in the right adrenal gland. The patient underwent a left laparoscopic adrenalectomy. Microscopically, the tumor displayed histopathological features in common with ACTH-independent macronodular adrenocortical hyperplasia , including clear cell predominance, a pattern of small compact nests in clear cell areas, and a cord-like arrangement of small compact cells. An in situ hybridization study demonstrated the hybridization signals for P-450scc, 3β-HSD, P-450c21, P-45011β, and P-45017αwhich were observed in the clear cells as well as compact cells, the compact cells being more intensely stained. This case indicates the ability of autonomous cortisol production to become clear during a very short term and a more detailed and careful short-time follow-up should be recommended in patients with adrenal incidentalomas.症例は57 歳，女性．45 ｍｍｘ 33 ｍｍの左副腎偶発腫瘍の精査目的で当科に入院となった．高コルチゾール血症による身体所見は認めず，内分泌学的検査では，コルチゾールの夜間９時の値が軽度上昇している以外は，ACTH，コルチゾール値ともほぼ正常で日内リズムも保たれていた．しかしデキサメサゾン1mg 抑制試験ではコルチゾールは完全には抑制されなかった．よってわずかな間脳下垂体副腎系の異常が示唆され，腫瘍径も4cm を超えており摘出も検討したが，患者さんは保存的経過観察を希望され手術は施行しなかった．ところが３ケ月後の血液検査でACTH 値は感度以下の低値で，コルチゾール基礎値は正常であるが，デキサメサゾン1mgまたは8mg 抑制試験でコルチゾールは完全に抑制されなかった．アドステロール副腎シンチグラフィー検査では左副腎腫瘍に高集積を認め，右副腎には集積を認めなかった．そこで今回患者さんの同意を得て腹腔鏡下で左副腎摘出術を施行した．摘出副腎腫瘍は光顕像ではACTH-independent macronodularadrenocortical hyperplasia (AIMAH)の組織像であり，in situ hybridization studyではcompact cellにより強いP-450scc, 3β-HSD，P-450c21，P-45011βそしてP-45017αのシグナルが認めた．本症例は短期間のうちにコルチゾールの自律的分泌能が明確となった副腎偶発腫瘍の一例であり，より注意深い，詳細な，短期間のうちの内分泌学的経過観察が副腎偶発腫瘍に対して必要であることが示唆された