The effects of chest drainage on pressure-controlled ventilation.

BACKGROUND: The use of pressure-controlled ventilation (PCV) for anesthesia management is becoming more commonly used. Chest drainage is commonly performed after thoracic surgery, and the negative pressure it generates might affect the transpulmonary pressure (TPP). In the present study, we investigated how chest drainage could affect ventilating conditions during PCV. METHODS: We created a hand-made simple thoracic and lung model, which was connected to an anesthesia machine. The tidal volume (TV) was measured with positive end-expiratory pressure (PEEP) 0 and no chest drainage (baseline), followed by 10 cmH2O PEEP/no drainage, 10 cmH2O PEEP/drainage with - 10 cmH2O and 10 cmH2O PEEP/drainage with - 20 cmH2O. Finally, TV with 20 cmH2O and 30 cmH2O PEEP/no drainage was measured. Driving (inspiratory) pressure was maintained at 20 cmH2O during the whole experiment. RESULTS: TV was significantly increased by applying 10 cmH2O PEEP compared with baseline, further increased by applying - 10 cmH2O by drainage, similar to the value with PEEP 20 cmH2O with no drainage (end-tidal TPP of 20 cmH2O for both). TV decreased to < 50% of the baseline by applying 10 cmH2O PEEP with - 20 cmH2O by drainage, which was similar to that with 30 cmH2O PEEP with no drainage (end-tidal TPP of 30 cmH2O for both). CONCLUSIONS: TV was maintained at similar levels with the same TPP, regardless of PEEP or negative pressure by chest drainage change, suggesting that negative intrapleural pressure by the chest tube drainage system might mimic PEEP from the point of TV.

A case requiring re-thoracotomy due to a significant reduction of tidal volume after commencement of chest tube drainage under pressure control ventilation following lower lobectomy.

BACKGROUND: The use of pressure-controlled ventilation (PCV) during one lung ventilation (OLV) has been popular to avoid high airway pressure. We experienced a case of a significant reduction of tidal volume (TV) after commencement of chest tube drainage under PCV following lower lobectomy, which required re-thoracotomy to evaluate the degree of air leak. CASE PRESENTATION: A 70-year-old man was scheduled for a lower lobectomy. OLV was managed by PCV. The driving pressure was set at 15-20 cmH2O with 4 cmH2O of positive end-expiratory pressure (PEEP). A chest drainage tube was placed after completion of lobectomy. To switch OLV to two lung ventilation (TLV), PCV settings were changed to the driving pressure at 10 cmH2O with 4 cmH2O of PEEP, which generated 450 ml of TV. Immediately after applying drainage (-10 cmH2O), TV decreased down to 250 ml. To maintain 450 ml of TV, PCV was switched to volume-controlled ventilation with 450 ml of TV, which raised the plateau pressure close to 24 cmH2O. Re-thoracotomy was done; however, significant findings were not detected. CONCLUSIONS: We experienced a case of a significant reduction of TV immediately after chest tube drainage following lower lobectomy. Probably, negative intrapleural pressure increased the residual volume, which might have significantly affected the limited lung volume after lobectomy, resulting in decreasing TV during PCV.

Update on the SedLine® algorithm for calculating the Patient State Index of older individuals during general anesthesia: a randomized controlled trial.

BACKGROUND: The SedLine® sensor processes (Masimo Corporation; Irvine, CA, USA) raw electroencephalogram (EEG) signals and displays the depth of sedation as a Patient State Index (PSi). Reliance on standard processed EEG data and failure to recognize age-related effects can lead to an erroneous interpretation that low-amplitude EEG findings in an older patient signify an insufficient depth of anesthesia presented as abnormally high PSi values (AHPSi). We hypothesized that the incidence of AHPSi would decrease with the use of the recently-updated version of the SedLine® sensor, in which the Bispectral Index (BIS) values were used to titrate anesthesia. METHODS: Thirty-three patients undergoing sevoflurane-remifentanil anesthesia were randomized into two groups. SedLine® sensors designed based on an old (v.1203) or updated (v.2000) algorithms were used. The BIS (v.4.1) and absolute index of total EEG power (TP) were simultaneously recorded. The attending anesthesiologists titrated the anesthetics, and BIS was maintained at 40-60. The incidence of AHPSi (PSi>50 with BIS 40-60) was calculated during the first 30 min after the start of surgery. RESULTS: Compared to the old algorithm group, the incidence of AHPSi was significantly lower in the updated algorithm group (26.7% vs. 4.2%, P<0.001). Lower TP values and the use of the old algorithm have significant effect on increased PSi values (P<0.001). CONCLUSIONS: The incidence of AHPSi decreased with the use of the updated version of the SedLine® algorithm.

Adjustment of oxygen reserve index (ORi™) to avoid excessive hyperoxia during general anesthesia.

The Oxygen Reserve Index (ORi™) is a non-invasive variable that reflects oxygenation continuously. The aims of this study were to examine the relationship between arterial partial pressure of oxygen (PaO2) and ORi during general anesthesia, and to investigate the usefulness of ORi as an indicator to avoid hyperoxia. Twenty adult patients who were scheduled for surgery under general anesthesia with arterial catheterization were enrolled. After induction of general anesthesia, inspired oxygen concentration (FiO2) was set to 0.33, and arterial blood gas analysis was performed. The PaO2 and ORi at the time of blood collection were recorded. After that, FiO2 was changed to achieve an ORi around 0.5, 0.2, and 0, followed by arterial blood gas analysis. The relationship between ORi and PaO2 was then investigated using the data obtained. Eighty datasets from the 20 patients were analyzed. When PaO2 was less than 240 mmHg (n = 69), linear regression analysis showed a relatively strong positive correlation (r2 = 0.706). The cut-off ORi value obtained from the receiver operating characteristic curve to detect PaO2 ≥ 150 mmHg was 0.21 (sensitivity 0.950, specificity 0.755). Four-quadrant plot analysis showed that the ORi trending of PaO2 was good (concordance rate was 100.0%). Hyperoxemia can be detected by observing ORi of patients under general anesthesia, and thus unnecessary administration of high concentration oxygen can possibly be avoided.

Usefulness of oxygen reserve index (ORi™), a new parameter of oxygenation reserve potential, for rapid sequence induction of general anesthesia.

The oxygen reserve index (ORi™) is a new parameter for monitoring oxygen reserve noninvasively. The aim of this study was to examine the usefulness of ORi for rapid sequence induction (RSI). Twenty adult patients who were scheduled for surgical procedures under general anesthesia were enrolled. After attaching a sensor capable of measuring ORi, oxygen (6 L/min) and fentanyl (2 µg/kg) were administered. After 3 min, propofol 2 mg/kg and rocuronium 1 mg/kg were administered without ventilation. Regardless of changes in ORi, tracheal intubation was performed either 2 min after administration of propofol or when percutaneous oxygen saturation (SpO2) reached 98%. Ventilation was then provided with oxygen at 6 L/min, and trends in ORi and SpO2 during RSI were observed. Data from 16 of the 20 patients were analyzed. Before oxygen administration, the median SpO2 was 98% [interquartile range (IQR) 97-98] and ORi was 0.00 in all patients. At 3 min after starting oxygen administration, the median SpO2 was 100% (IQR 100-100) and the median ORi was 0.50 (IQR 0.42-0.57). There was an SpO2 decline of 1% or more from the peak value after propofol administration in 13 patients, and 32.5 s (IQR 18.8-51.3) before the SpO2 decrease, ORi began to decline in 10 of the 13 (77%) patients. The ORi trends enable us to predict oxygenation reduction approximately 30 s before SpO2 starts to decline. By monitoring ORi, the incidence related to hypoxemia during RSI could be reduced.

Effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) measurement.

To retrospectively investigate the effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) in 20 patients who underwent elective gynecologic surgery under general anesthesia. The study subjects were patients who underwent elective gynecologic surgery under general anesthesia between April 2016 and January 2017, and were administered a 5-ml intravenous injection of 0.4% indigo carmine for clinical purposes during surgery with ORi monitoring. Changes in ORi within 20 min after indigo carmine injection were observed. A relevant decrease in ORi was defined as ≥ 10% reduction in ORi from pre-injection level. ORi rapidly decreased after indigo carmine intravenous injection in all patients. In 10 of 19 patients, ORi decreased to 0 after indigo carmine injection. The median lowest value of ORi was 0 (range 0-0.16) and the median time to reach the lowest value of ORi was 2 min (range 1-4 min) after injection. ORi values returned to pre-injection levels within 20 min in 13 of 19 patients, and the median time to return to pre-injection levels was 10 min (range 6-16 min) after injection. During ORi monitoring it is necessary to consider the rapid reduction in ORi after intravenous injection of indigo carmine.

Effects of indigo carmine intravenous injection on noninvasive and continuous total hemoglobin measurement with using the Revision L sensor.

The effects of intravenous injection of indigo carmine on noninvasive and continuous total hemoglobin (SpHb) measurement were retrospectively evaluated with the Revision L sensor. The subjects were 18 patients who underwent elective gynecologic surgery under general anesthesia. During surgery, 5 mL of 0.4 % indigo carmine was injected intravenously, and changes in SpHb concentrations between before and after the injection were evaluated. The mean age was 52.4 ± 12.8 years. Before injection, the median SpHb level was 10.1 (range, 6.8-13.4) g/dL. The results demonstrated no change in SpHb concentration between before and after indigo carmine injection as detected by the Revision L sensor. SpHb measurements as determined with the Revision L sensor were not affected, even after the intravenous injection of indigo carmine.

Effects of indigo carmine intravenous injection on noninvasive and continuous total hemoglobin measurement.

The effects of an intravenous injection of indigo carmine on noninvasive and continuous total hemoglobin (SpHb) measurement were retrospectively evaluated. The subjects were 21 patients who underwent elective gynecologic surgery under general anesthesia. During surgery, 5 mL of 0.4 % indigo carmine was intravenously injected, and subsequent changes in SpHb concentrations were evaluated. The results demonstrate that the pre-injection SpHb level was 10 g/dL, and the minimum post-injection SpHb level was 8.3 g/dL. The amount of decrease was 1.8 g/dL. The time to reach the minimum value was 4 min, and the time to return to the pre-injection value was 15 min. The decrease in SpHb was greater in the group with a perfusion index (PI) < 1.4 than in the group with a PI > 1.4. The assessment of SpHb after an intravenous injection of indigo carmine necessitates caution.

Life-threatening urethral hemorrhage after placement of a Foley catheter in a patient with uroseptic disseminated intravascular coagulation due to chronic urinary retention induced by untreated benign prostatic hyperplasia.

Case: A 77-year-old man with severe septic disseminated intravascular coagulation following urinary infection was transported to our hospital. He had developed urinary retention induced by untreated prostatic hyperplasia. Immediate drainage with a Foley catheter was successfully carried out, but the hematuria progressed to life-threatening hemorrhage. Outcome: Complete hemostasis was impossible by surgical treatment because the tissue around the prostatic urethra was very fragile and hemorrhagic. Organized treatments (continuous hemodiafiltration combined with polymyxin-B immobilized fiber column hemoperfusion and systemic treatment with antibiotics and coagulation factors) were commenced soon after the operation. The patient eventually recovered from the septic disseminated intravascular coagulation. Conclusion: This case report illustrates the risk of placement of Foley catheters in patients with severe septic disseminated intravascular coagulation.

THE EFFECT OF OBESITY ON DOSE OF DEXMEDETOMIDINE WHEN ADMINISTERED WITH FENTANYL DURING POSTOPERATIVE MECHANICAL VENTILATION--RETROSPECTIVE.

We carried out a retrospective investigation on the effect of obesity on dexmedetomidine (DEX) requirements when administered with fentanyl (FEN) during mechanical ventilation after major surgeries. After Institutional Review Board approval, 14 obese patients with a body mass index (BMI) ≥ 30 kg/m(2) and the same number of non-obese patients with similar backgrounds to the obese patients were selected from medical records. Doses of DEX in the first 48 h or until the end of sedation or extubation were calculated for comparison. In addition to comparison of dosing between the groups, associations between total body weight (TBW), BMI, and lean body mass (LBM) values and doses of DEX (mcg/h), between BMI and various indices (i.e., amount per TBW per hour and amount per LBM per hour) of DEX doses, and between above indices of DEX and FEN doses were also examined. There were no significant differences in DEX dose indices between the groups. However, DEX requirements (mcg/h) were significantly increased with TBW (kg) (r = 0.51, P = 0.003), BMI (r = 0.49, P = 0.006) and LBM (kg) (r = 0.42, P = 0.02), which might have enhanced the DEX metabolism with physiological changes with obesity. These findings will be beneficial for future clinical pharmacological analysis of DEX.

Plasma ropivacaine concentration following ultrasound-guided subcostal transversus abdominis plane block in adults.

Ultrasound-guided subcostal transversus abdominis plane block (TAPB) is widely used for abdominal surgery; however, arterial plasma concentration of the anesthetic ropivacaine after the blockade is still unclear. We evaluated ropivacaine concentration after subcostal TAPB in adult patients undergoing upper abdominal surgery. Twelve patients with American Society of Anesthesiologists physical status 1-2 were enrolled. They received ultrasound-guided subcostal TAPB with 0.45 % ropivacaine at 3 mg/kg. Arterial plasma samples were collected at 15, 30, 45, 60, 90, and 120 min after the blockade and analyzed for total ropivacaine concentration using liquid chromatography and mass spectrometry. At every time point, the maximum concentrations (C(max)), and time to the C max (T(max)) were recorded. The mean C(max) and T(max) were 1.87 (0.78) µg/ml and 31.3 (16.7) min, respectively. No adverse events or clinical symptoms indicating systemic toxicity were observed during this study. The study demonstrated that administration of ropivacaine at 3 mg/kg during subcostal TAPB led to rapid increases in plasma concentration of the anesthetic during the first 2 h after the blockade. C(max) nearly reached the threshold for systemic toxicity.

[A case of newly diagnosed moyamoya disease in a pregnant patient with a ruptured aneurysm of the distal anterior choroidal artery embolized using N-butyl cyanoacrylate].

Here we describe a rare case of a pregnant patient with a ruptured aneurysm of the distal anterior choroidal artery(AChA)that was embolized using n-butyl cyanoacrylate(NBCA). The 32-year-old patient was 24 weeks pregnant. She suddenly suffered from headache and vomiting. On admission, she was somnolent with left hemiparalysis and had a manual muscle test score of 1/5. Computed tomography(CT)images revealed a cerebral hemorrhage from the right temporal lobe to the lateral ventricle with intraventricular hemorrhage. Cerebral angiography showed severe stenosis at the terminal portion of the right internal carotid artery and a surrounding abnormal vascular network. She was diagnosed with unilateral moyamoya disease, and a direct surgical evacuation of the hemorrhage was performed on the same day. The following day, cerebral angiography showed enlargement of a distal AChA aneurysm that, as suspected, had caused the hemorrhage. The aneurysm was treated by the injection of 20% NBCA into the distal AChA and the aneurysm. After surgery, magnetic resonance imaging showed ischemic changes in the ventral posterolateral nucleus of the thalamus without neurological deficits. The patient became lucid, and the left hemiparalysis improved. The rest of the pregnancy was uneventful. At 37 weeks, she delivered a normal baby by elective caesarean section. When treating pregnant patients with moyamoya disease and a ruptured cerebral artery aneurysm, it is extremely important to cooperate with obstetricians to ensure a safe pregnancy and delivery.

[A case of respiratory distress due to massive pleural effusion after surgery for ovarian tumor].

A 59-year-old woman with ovarian tumor was scheduled for radical hysterectomy under general anesthesia. Preoperative examination showed massive ascites and slight pleural effusion. Since respiratory status had improved by oxgen therapy, she underwent a surgery as scheduled, although she complained of slight dyspnea and low Sp(O2). Induction of anesthesia was uneventful. However, oxygenation deteriorated and airway pressure increased after suction of ascites during the operation. We treated it with increased FI(O2). After surgery, we found bilateral massive pleural effusion on the chest X-ray and drained it. Oxygenation improved, and the endotracheal tube was removed. Patients with ovarian tumor with pleural effusion and ascites may have desaturation due to increased pleural effusion during the operation, or pleural effusion might increase preoperatively. Therefore, we need to be cautious about anesthetic management of them and examine chest X-ray and arterial blood gas frequently.

Validation of continuous and noninvasive hemoglobin monitoring by pulse CO-oximetry in Japanese surgical patients.

We evaluated the accuracy of noninvasive and continuous total hemoglobin (SpHb) monitoring with the Radical-7(®) Pulse CO-Oximeter in Japanese surgical patients before and after an in vivo adjustment of the first SpHb value to match the first reference value from a satellite laboratory CO-Oximeter. Twenty patients undergoing surgical procedures with general anesthesia were monitored with Pulse CO-Oximetry for SpHb. Laboratory CO-Oximeter values (tHb) were compared to SpHb at the time of the blood draws. Bias, precision, limits of agreement and correlation coefficient of SpHb compared to tHb were calculated before and after SpHb values were adjusted by subtracting the difference between the first SpHb and tHb value from all subsequent SpHb values. Trending of SpHb to tHb and the effect of perfusion index (PI) on the agreement of SpHb to tHb were also analyzed. Ninety-two tHb values were compared to the SpHb. Bias ± 1SD was 0.2 ± 1.5 g/dL before in vivo adjustment and -0.7 ± 1.0 g/dL after in vivo adjustment. Bland-Altman analysis showed limits of agreement of -2.8 to 3.1 g/dL before in vivo adjustment and -2.8 to 1.4 g/dL after in vivo adjustment. The correlation coefficient was 0.76 prior to in vivo adjustment and 0.87 after in vivo adjustment. In patients with adequate perfusion (PI ≥1.4) the correlation coefficient was 0.89. In vivo adjustment of SpHb significantly improved the accuracy in our cohort of Japanese surgical patients. The strongest correlation between SpHb and tHb values was observed in patients with adequate peripheral perfusion suggesting that low perfusion may affect the accuracy of SpHb monitoring.

Examination of the usefulness of non-invasive stroke volume variation monitoring for adjusting fluid supplementation during laparoscopic adrenalectomy in patients with pheochromocytoma.

PURPOSE OF THE STUDY: The measurement of stroke volume variation (SVV) using the FloTrac™ system (Edwards Lifescience, USA) is useful to estimate cardiac preload. We evaluated the benefits of SVV monitoring for adjusting fluid supplementation during laparoscopic adrenalectomy under anesthesia in patients with pheochromocytoma. SUBJECTS AND METHODS: Among 10 patients who underwent laparoscopic adrenalectomy for pheochromocytoma in our institution from June 2004 to December 2009, SVV was not monitored in 5 patients (group I) and in the other 5 patients (group II), SVV monitoring was performed. Subject age, height and body weight, total volume of fluid supplemented, blood loss, urine output and net fluid in-out balance during the procedure were retrospectively assessed. In those with SVV monitoring, infusion volume was adjusted for SVV less than 13%. RESULTS: There were significant differences in the patient age and body weight between the two groups (group I: 64.2 years old and 55.1 kg; group II: 43.6 years old and 71.7 kg). Both total infusion volume and urine output were significantly higher in group I compared with group II (5,610 vs. 2,400 ml and 1,125 vs. 750 ml, respectively). Total blood loss was similar between the two groups. Values of the net fluid balance divided by the body weight and total anesthesia period (hr) were significantly lower in group II compared with group I (I; +13.2 in group I and +6.2 in group II, ml/kg/hr). CONCLUSIONS: These data suggest that SVV monitoring is helpful to estimate the optimal volume for fluid supplementation and could prevent excessive fluid infusion during surgical procedures.