Use of laboratory testing for prediction of postoperative bleeding volume in cardiovascular surgery

BACKGROUND

Coagulopathy and following massive bleeding are complications of cardiovascular surgery, particularly occurring after procedures requiring prolonged cardiopulmonary bypass (CPB). Reliable and rapid tests for coagulopathy are desirable for guiding transfusion. Measuring multiple coagulation parameters may prove useful. The purpose of this study is to determine the laboratory parameters predicting massive bleeding.

METHODS

In a prospectively collected cohort of 48 patients undergoing cardiovascular surgery, markers of coagulation and fibrinolysis were measured using automated analyzer and their correlations with bleeding volume were determined.

RESULTS

Operation time was 318 (107-654) min. CPB time was 181 (58-501) min. Bleeding volume during surgery was 2269 (174-10,607) ml. Number of transfusion units during surgery were packed red blood cells 12 (0-30) units, fresh frozen plasma 12 (0-44) units, platelets 20 (0-60) units and intraoperative autologous blood collection 669 (0-4439) ml. Post-surgery activities of coagulation factors II (FII), FV, FVII, FVIII, FIX, FX, FXI and FXII were decreased. Values of fibrinogen, antithrombin, α2 plasmin inhibitor (α2PI) and FXIII were also decreased. Values of thrombin-antithrombin complex (TAT) were increased. Values of FII, FIX, FXI and α2PI before surgery were negatively correlated with bleeding volume (FII, r = - 0.506: FIX, r = - 0.504: FXI, r = - 0.580; α2PI, r = - 0.418). Level of FIX after surgery was negatively correlated with bleeding volume (r = - 0.445) and level of TAT after surgery was positively correlated with bleeding volume (r = 0.443).

CONCLUSIONS

These results suggest that several clinical and routine laboratory parameters of coagulation were individually associated with bleeding volume during cardiovascular surgery. Determining the patterns of coagulopathy may potentially help guide transfusion during cardiovascular surgery.

Desflurane for management of decompressive laminectomy in a patient with hereditary spastic paraplegia: a case report

Background

Hereditary spastic paraplegia (HSP) is a rare, genetic neurodegenerative condition. Thus far, ideal anesthetic management is not established for patients with HSP; therefore, careful selection and dosage of anesthetic agents is required.

Case presentation

A 54-year-old woman with HSP, who was diagnosed with severe lumbar spinal canal stenosis, underwent decompressive laminectomy to relieve her back pain. Preoperatively, she experienced slight difficulty in walking independently; however, she exhibited no other dysfunction. Anesthesia was maintained with desflurane after tracheal intubation. Rocuronium and sugammadex were used for neuromuscular blockade and reversal, respectively, with neuromuscular monitoring equipment. The patient showed uneventful postoperative recovery without signs of neurological deterioration after extubation.

Conclusions

Our successful experience in this case implies that, for patients with neuromuscular diseases, including HSP, desflurane may be an option for anesthetic management; moreover, careful assessment (e.g., medical condition, bispectral index, and train-of-four) should be performed prior to administration of anesthesia.

Transfer of a minimally invasive mitral valve repair program from a high-volume center to a very low volume center: how many cases are necessary to maintain acceptable results?

OBJECTIVE

To investigate whether minimally invasive mitral valve repair (MIMVR) can be transferred from a high-volume center into a very small volume center and to clarify how many cases are necessary for maintenance of this program, early outcomes of MIMVR in Asahikawa Medical University were compared with those results in patients operated by a single surgeon in Duesseldorf University Hospital.

METHODS

Sixty-five patients who underwent MIMVR in Asahikawa Medical University (group A) between May 2014 and July 2018 and 134 patients who underwent MIMVR in Duesseldorf University Hospital (group D) between September 2009 and January 2014 by a surgeon who started MIMVS later in Asahikawa were retrospectively analyzed.

RESULTS

In group D, there were more patients with ischemic mitral valve regurgitation and with annular calcification than in group A. Survival rate at 6 months and 1 year was 98.5% and 98.5% in group A and 92.9% and 91.3% in group D, respectively. EuroSCORE II was significantly higher in patients dead within 30 days and within the first year.

CONCLUSIONS

The present study demonstrated that MIMVR programs can be transferred with acceptable early results into very low volume centers, if the team is developed by surgeons who are well trained and experienced in MIMVR. Moreover, the present study suggested that case number for maintenance of acceptable results may be obviously less than the previous recognition that this kind of specialized surgery could be maintained with at least 50 cases annually. However, meticulous preparations for surgery are essential for satisfactory surgical outcomes.

Cerebral Circulation During Retrograde Cerebral Perfusion: Evaluation Using Laser Speckle Flowgraphy

BACKGROUND

The cerebroprotective effect of retrograde cerebral perfusion (RCP) and selective antegrade cerebral perfusion (SCP) still remains controversial. Laser speckle flowgraphy has shown much promise for novel perioperative neuromonitoring by assessing blood flow of the optic nerve head. This study aimed to evaluate the cerebral microcirculation in humans using laser speckle flowgraphy during simple circulatory arrest, RCP, and SCP under moderate hypothermia and to investigate whether RCP under moderate hypothermia is a reliable method of cerebral protection.

METHODS

A total of 23 consecutive patients who underwent a scheduled aortic arch or hemiarch surgical procedure on thoracic aorta aneurysm were enrolled. The laser speckle flowgraphy measurement that calculates mean blur ratio, a parameter of cerebral circulation, was obtained 6 times: after induction of anesthesia, baseline (T1), after initiation of cardiopulmonary bypass with cardiac arrest (T2), simple circulatory arrest (T3), RCP (T4), SCP (T5), and after the termination of cardiopulmonary bypass (T6).

RESULTS

Both mean blur ratios of simple circulatory arrest and RCP were significantly decreased compared with baseline. In contrast, no significant differences were observed between simple circulatory arrest and RCP. The mean blur ratio of SCP was significantly increased compared with both simple circulatory arrest and RCP.

CONCLUSIONS

In conclusion, no significant difference was observed in the cerebral circulation between RCP and simple circulatory arrest without adjunctive strategy under moderate hypothermia. In contrast, the cerebral circulation during SCP was significantly higher than simple circulatory arrest and RCP. These results suggest that cerebral microcirculation may not be adequate during RCP compared with SCP under moderate hypothermia.

Conservative management for iatrogenic gastric perforation by transesophageal echocardiography

Background

Though several cases of upper gastrointestinal tract injury caused by transesophageal echocardiography (TEE) have been reported, gastric perforation is very rare. Herein, we report the case of TEE-associated gastric perforation that was successfully treated conservatively.

Case presentation

An 82-year-old man underwent mitral valve repair. Postoperative esophagogastroduodenoscopy and computed tomography revealed gastric perforation. Surgical treatment was initially considered, but conservative management was selected to avoid increasing operative stress, to minimize the need for total gastrectomy (including the lower esophagus), and to minimize the risk of a potential intraperitoneal infection spreading to the thoracic cavity.

Conclusion

Conservative management of gastric perforation can be successful even when the perforation is recognized later than 12 h following the event, provided that there are no abdominal symptoms and no signs of peritoneal effusion or sepsis. Our experience suggests that conservative management is a feasible option for treating TEE-associated gastric perforation in appropriately selected cases.

Reliability of Cardiac Output Measurements Using LiDCOrapid and Calibration by Transesophageal Echocardiography With the Continuous Pulmonary Artery Thermodilution Method in Patients Undergoing Aortic Valve Replacement for Aortic Stenosis

OBJECTIVE

This study investigated the accuracy of arterial waveform analysis estimations of cardiac output (CO_AW) and the efficacy of calibrations involving transesophageal echocardiography with continuous cardiac output values obtained using a pulmonary artery catheter.

DESIGN

Prospective cohort study.

SETTING

University hospital operating room.

PARTICIPANTS

Twelve patients undergoing aortic valve replacement for aortic stenosis.

INTERVENTIONS

A pulmonary artery catheter was placed in each patient, and continuous cardiac output was determined using thermodilution principles. LiDCOrapid and transesophageal echocardiography were used to measure CO_AW and to perform the calibration, respectively.

MEASUREMENTS AND MAIN RESULTS

Simultaneous recording of continuous cardiac output and CO_AW values were performed every 20 minutes, after inducing anesthesia. CO_AW was calibrated using transesophageal echocardiography (CO_AW-cal) before and after initiating cardiopulmonary bypass (CPB); the CO_AW and CO_AW-cal were recorded concurrently using a LiDCOrapid monitor. For the pre-CPB dataset (34 data pairs), the mean bias and percentage error were, respectively, 0.10 L/min and 34% for CO_AW versus continuous cardiac output and -0.098 L/min and 27% for CO_AW-cal versus continuous cardiac output. Similarly, for the post-CPB (45 data pairs), the mean bias and percentage error were, respectively, 0.75 L/min and 34% for CO_AW and 0.059 L/min and 26% for CO_AW-cal. A 4-quadrant plot demonstrated an acceptable pre-CPB concordance rate of 93.3% for CO_AW and 93.8% for CO_AW-cal.

CONCLUSION

CO_AW measurements, using LiDCOrapid, have acceptable trending ability pre-CPB. The determination of cardiac output variations, using transesophageal echocardiography, is useful for managing patients undergoing aortic valve replacement for aortic stenosis.

Cerebral circulation estimated by laser speckle flowgraphy in retrograde femoral arterial perfusion during minimally invasive cardiac surgery

OBJECTIVES

Laser speckle flowgraphy (LSFG) is a novel modality to assess blood flow of the optic nerve head (ONH), which is reported to be a surrogate marker of cerebral microcirculation. We conducted LSFG measurements during minimally invasive cardiac surgery with retrograde femoral arterial perfusion and evaluated its feasibility and usability as a neuromonitor.

METHODS

We prospectively enrolled 7 patients who underwent mitral valve repair through a right minithoracotomy with retrograde femoral arterial perfusion. LSFG was used to analyse the ONH blood flow based on examinations of the mean blur rate (MBR). The MBR was measured after the induction of anaesthesia (time 1); after the initiation of cardiopulmonary bypass (time 2); during cardiac arrest (time 3) and after the termination of cardiopulmonary bypass (time 4).

RESULTS

All procedures were performed successfully, and there were no neurovascular complications or deaths. LSFG measurements were easily and uneventfully conducted without any related complications. The MBR was 11.2 ± 2.3 at time 1, 11.1 ± 1.8 at time 2, 11.3 ± 1.7 at time 3 and 13.6 ± 3.5 at time 4. Statistically, the MBR at time 4 was significantly higher than those at all other times ( P  < 0.05).

CONCLUSIONS

LSFG measurements were safely conducted during minimally invasive cardiac surgery and assessed ONH blood flow quantitatively. We consider this modality to be easy to manipulate and less operator dependent, resulting in good reproducibility. The results are well visualized and compared quantitatively. Our result suggests that LSFG might be an accurate neuromonitor.

Clinical trial registration

clinicaltrials.gov : 15102-2.

Preparing for the unexpected: special considerations and complications after sugammadex administration

Sugammadex, a modified gamma-cyclodextrin, has changed clinical practice of neuromuscular reversal dramatically. With the introduction of this selective relaxant binding agent, rapid and reliable neuromuscular reversal from any depth of block became possible. Sugammadex can reverse neuromuscular blockade without the muscarinic side effects typically associated with the administration of acetylcholinesterase inhibitors. However, what remained unchanged is the incidence of residual neuromuscular blockade. It is known that sugammadex cannot always prevent its occurrence, if appropriate dosing is not chosen based on the level of neuromuscular paralysis prior to administration determined by objective neuromuscular monitoring. Alternatively, excessive doses of sugammadex administered in an attempt to ensure full and sustained reversal may affect the effectiveness of rocuronium in case of immediate reoperation or reintubation. In such emergent scenarios that require onset of rapid and reliable neuromuscular blockade, the summary of product characteristics (package insert) recommends using benzylisoquinolinium neuromuscular blocking agents or a depolarizing agent. However, if rapid intubation is required, succinylcholine has a significant number of side effects, and benzylisoquinolinium agents may not have the rapid onset required. Therefore, prior administration of sugammadex introduces a new set of potential problems that require new solutions. This novel reversal agent thus presents new challenges and anesthesiologists must familiarize themselves with specific issues with its use (e.g., bleeding risk, hypermagnesemia, hypothermia). This review will address sugammadex administration in such special clinical situations.

Morphologic Evaluation of the Mitral Annulus During Displacement of the Heart in Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE

To evaluate the morphologic changes of the mitral annulus using 3-dimensional transesophageal echocardiography during heart displacement to expose the anastomosis site in off-pump coronary artery bypass surgery (OPCAB).

DESIGN

Prospective case series.

SETTING

Single center, university hospital.

PARTICIPANTS

The study comprised 34 consecutive patients who underwent OPCAB of the left circumflex artery (LCX) and the right coronary artery (RCA).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mitral annulus parameters were measured using the Mitral Valve Quantification program after sternotomy (physiologic position) and during displacement of the heart to expose the LCX (LCX position) and the RCA (RCA position). The height of the mitral annulus was significantly lower in the LCX (5.76 ± 0.90 mm) and RCA (5.92 ± 0.97 mm) positions than in the physiologic position (6.96 ± 0.99 mm; both p < 0.0001). The percent change in the height of the mitral annulus was significantly greater in the mitral regurgitation group than in the mitral regurgitation nondeterioration group when in the LCX (-16.3% ± 6.0% v -11.9% ± 3.3%, p = 0.0203) and RCA (-16.9% ± 6.3% v -12.1% ± 3.8%, p = 0.0207) positions. The anteroposterior and intercommissural diameters, annulus perimeter, and surface area of the mitral annulus did not differ significantly among all heart positions.

CONCLUSIONS

The mitral annulus flattened and lost its saddle shape without expanding while in the LCX and RCA positions. The greater percent change in the height of the mitral annulus may aggravate mitral regurgitation.

A case of iatrogenic pneumothorax in which chest tube placement could be avoided by intraoperative evaluation with transthoracic ultrasonography

We report a case of iatrogenic pneumothorax in which chest tube placement was avoided by continuous intraoperative evaluation with transthoracic ultrasonography. A 53-year-old man had undergone a subsegmentectomy. While attempting to place a central venous catheter in the right internal jugular vein after the induction of anesthesia, we identified gas absorption during the puncture and suspected a pneumothorax. Chest X-ray revealed an ~5-mm collapse of the right lung apex. Tension pneumothorax was a concern during surgery because of the long-term positive pressure ventilation, but we decided to start the operation without preventative chest tube placement. During the operation, we regularly observed the midclavicular line of the second intercostal space using ultrasound. The operation was completed uneventfully. In this case, we effectively utilized ultrasound and avoided preventive chest tube placement and the associated complications. Transthoracic ultrasonography could be performed easily and continuously during surgery and was effective for evaluating the progression of an intraoperative pneumothorax.

Cerebral Infarction by Paradoxical Gas Embolism During Laparoscopic Liver Resection with Injury of the Hepatic Vessels in a Patient without a Right-to-Left Systemic Shunt

Patient: Male, 60

Final Diagnosis: Hepatocellular carcinoma

Symptoms: None

Medication: —

Clinical Procedure: Hepatectomy

Specialty: Surgery

Comparison of caudal ropivacaine-morphine and paravertebral catheter for major upper abdominal surgery in infants

BACKGROUND

The caudal epidural block is one of the most commonly used regional anesthetic techniques in children. Administration of morphine via caudal injection enables analgesia, even for upper abdominal surgery. The thoracic paravertebral block has also been successfully used to treat perioperative pain during upper abdominal procedures in pediatric patients.

AIM

In the current study, we compared the two regional techniques for upper abdominal surgery in infants to determine whether one of them was preferable to the other.

METHODS

Consecutive patients under 12 months of age who underwent upper abdominal surgery were retrospectively divided according to the chosen postoperative analgesia: Group C, caudal ropivacaine-morphine; Group P, paravertebral catheter. We analyzed the following outcomes: requirement for additional analgesics, pain scores, need for mechanical ventilation and oxygen dosage, postoperative blood pressure and heart rate, time to pass first stool, time until first full meal, and complications.

RESULTS

Twenty-one consecutive patients were included: 10 in Group C and 11 in Group P. Median age at surgery was 80 (47.5-270.0) and 84.5 (34.3-287.5) days, respectively. No difference was found between the two groups in requirement for additional analgesics at 24 h after surgery (median 1 in Group C vs 1 in Group P, P = 0.288, 95% CI: -2 to 1). BOPS pain scores were only lower in Group P when compared to Group C at 24 h after surgery (median 1 vs 2, P = 0.041, 95% CI: -2 to 0). None of the patients had perioperative complications.

CONCLUSIONS

In this small series, there was no significant difference between caudal ropivacaine-morphine and paravertebral catheter for postoperative care in infants undergoing upper abdominal surgery. Further prospective studies are needed to compare the efficacy and incidence of complications of caudal block and paravertebral catheter for postoperative analgesia.

Pregnancy suppresses neuropathic pain induced by chronic constriction injury in rats through the inhibition of TNF-α

Purpose

Pregnancy-induced analgesia develops during late pregnancy, but it is unclear whether this analgesia is effective against neuropathic pain. The detailed molecular mechanisms underlying pregnancy-induced analgesia have not been investigated. We examined the antinociceptive effect of pregnancy-induced analgesia in a neuropathic pain model and the expression of tumor necrosis factor (TNF)-α, glial fibrillary acidic protein (GFAP), Iba-1, and c-Fos in the spinal dorsal horn just before parturition.

Materials and methods

Female Sprague Dawley rats (200–250 g) were randomly assigned to one of four groups (pregnant + chronic constriction injury [CCI]; pregnant + sham injury; not pregnant + CCI; and not pregnant + sham injury). Separate groups were used for the behavioral and tissue analyses. CCI of the left sciatic nerve was surgically induced 3 days after confirming pregnancy in the pregnancy group or on day 3 in the not pregnant group. The spinal cord was extracted 18 days after CCI. TNF-α, GFAP, Iba-1, and c-Fos expression levels in the spinal dorsal horn were measured by Western blot analysis. Mechanical threshold was tested using von Frey filaments.

Results

The lowered mechanical threshold induced by CCI was significantly attenuated within 1 day before parturition and decreased after delivery. TNF-α expression in CCI rats was decreased within 1 day before parturition. Further, GFAP, Iba-1, and c-Fos expression in the spinal dorsal horn was reduced in the pregnant rats. Serum TNF-α in all groups was below measurable limits.

Conclusion

Our findings indicate that pregnancy-induced analgesia suppresses neuropathic pain through reducing spinal levels of TNF-α, GFAP, Iba-1, and c-Fos in a rat model of CCI.

Gene therapy with HSV encoding p55TNFR gene for HIV neuropathic pain: an evidence-based mini-review

While effective antiretroviral treatment makes human immunodeficiency virus (HIV)-related death decreased dramatically, neuropathic pain becomes one of the most common complications in patients with HIV/acquired immunodeficiency syndrome (AIDS). The exact mechanisms of HIV-related neuropathic pain are not well understood yet, and no effective therapy is for HIV-pain. Evidence has shown that proinflammatory factors (e.g., tumor necrosis factor alpha (TNFα)) released from glia, are critical to contributing to chronic pain. Preclinical studies have demonstrated that non-replicating herpes simplex virus (HSV)-based vector expressing human enkephalin reduces inflammatory pain, neuropathic pain, or cancer pain in animal models. In this review, we describe recent advances in the use of HSV-based gene transfer for the treatment of HIV pain, with a special focus on the use of HSV-mediated soluble TNF receptor I (neutralizing TNFα in function) in HIV neuropathic pain model.

Evaluation of cerebral circulation during retrograde perfusion by laser speckle flowgraphy

Laser speckle flowgraphy (LSFG) is an ophthalmologic equipment that qualitatively detects the blood flow of the optic nerve head, which is known to be related with cerebral microcirculation. LSFG can also measure the mean blur rate, which quantitatively calculates the blood flow. We aimed to assess the utility of LSFG in the evaluation of cerebral perfusion during aortic surgery under hypothermic circulatory arrest with retrograde and antegrade cerebral perfusion. Two patients underwent total arch replacement for aneurysm. The blood flow of the optic nerve head was monitored with LSFG and the mean blur rate value was measured during the surgery. The LSFG could detect the blood flow quantitatively in the optic nerve head during both retrograde and antegrade cerebral perfusion; and the value was correlated with rSO2 value.

Detection of dexmedetomidine in human breast milk using liquid chromatography-tandem mass spectrometry: Application to a study of drug safety in breastfeeding after Cesarean section

Several analytical methods for dexmedetomidine (DEX) in human plasma have been published, but quantification of DEX in human breast milk has not been described. In this article, we describe a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method suitable for quantification of DEX in human breast milk. DEX and an internal standard were extracted in a single liquid-liquid extraction step with diethyl ether from 200μL of human breast milk. HPLC was performed on a TSK-gel ODS-100V column with isocratic elution at a flow rate of 0.3mL/min using a mobile phase of 5mM ammonium formate:0.1% formic acid in acetonitrile (60:40, v/v). Detection was performed using an API4000 mass spectrometer with positive electrospray ionization. The method was validated in the concentration range of 10pg/mL (lower limit of quantification) to 2000pg/mL. The intra- and inter-day accuracy were within ±5.8% and precision was <6.31% based on the coefficient of variation. The recoveries of DEX in human breast milk were 82.4-87.9%. Recovery and matrix effects were consistent and reproducible for human breast milk. The method is robust and was successfully used in a study of drug safety in breastfeeding in patients after administration of DEX.

[The Efficacy of Ultrasound-guided Radial Artery Catheterization.]

BACKGROUND

The goal of this study was to evaluate in patients with peripheral arterial disease (PAD) whether ultrasound-guided radial artery catheterization decreased procedural time and number of attempts compared with the traditional palpation technique.

METHODS

Ultrasonography was evaluated for arte- rial catheterization after the traditional palpation tech- nique was unsuccessful in 480 seconds in 10 patients with PAD. The vascular access was performed by a single anesthesiologist. The successful catheterization time and the number of attempts were recorded. We also measured the diameter of the radial artery, the skin-to-artery distance, and the distance between the linear probe and puncture site.

RESULTS

The mean overall time per patient for catheter insertion was 220.0?112.6 sec in the ultra- sound group vs. 480 sec in the palpation group (P= 0.0029). The mean number of attempts was 1.30?0.48 in the ultrasound group vs. 4.50?0.53 in the palpation group (P = 0.0024). All catheterizations were success- ful, and no failure was encountered in the ultrasound group.

CONCLUSIONS

Ultrasound-guided radial artery cath- eterization took less time to establish the arterial line, and it reduced the number of attempts when com- pared with the palpation technique.

A case of gait disturbance caused by low-dose gabapentin

Gabapentin, an anticonvulsant agent, is now often used for the treatment of neuropathic pain all over the world. It is unclear whether the combined use of gabapentin, sodium valproate, and flunitrazepam results in enhancement of the side effect, a gait disturbance. A 60-year-old man was taking oral sodium valproate for symptomatic epilepsy after a brain contusion and flunitrazepam to relieve insomnia. Oral gabapentin therapy was started for suspected neuropathic pain. Although the initial dose of oral gabapentin (200 mg) relieved the pain, the lower extremities became weak, resulting in a gait disturbance. The therapy was restarted with a halved dose, and this resolved the gait disturbance and relieved the pain.

Pulse oximetry-derived pleth variability index can predict dexmedetomidine-induced changes in blood pressure in spontaneously breathing patients

STUDY OBJECTIVE

Hypertension or hypotension in patients receiving continuous infusions of dexmedetomidine (DEX) is often due to changes in vascular resistance caused by α2 receptor stimulation. We investigated whether baseline perfusion index (PI) and pleth variability index (PVI), derived from pulse oximetry readings, could predict DEX-induced changes in the hemodynamic status in spontaneously breathing patients.

DESIGN

Observational study.

SETTING

Operating room.

PATIENTS

Patients (American Society of Anesthesiologists performance status 1 or 2) scheduled to undergo lower extremity or abdominal procedures under regional anesthesia were approached.

INTERVENTIONS

The PI and PVI were set as baseline upon arrival in theater and were then measured at 2.5-minute intervals. Upon attaining stable hemodynamic status under spontaneous breathing, intravenous administration of DEX was initiated at 6 μg kg(-1) h(-1) for 10minutes, followed by continuous infusion at 0.6 μg kg(-1) h(-1).

MEASUREMENTS

Blood pressure, heart rate, PI, and PVI were measured. Hypertension was defined as an increase in systolic blood pressure (SBP) >15% and hypotension as a decrease in SBP <15% from baseline.

MAIN RESULTS

Baseline PI and PVI correlated with the degree of change in SBP. The maximum percentage increase as well as the maximum percentage of decrease in SBP from baseline correlated with baseline PI (r=0.418 [P=.005] and r=0.507 [P<.001], respectively) and PVI (r=-0.658 [P<.001] and r=-0.438 [P=.003], respectively). PVI <15 identified DEX-induced hypertension (sensitivity 94%, specificity 85%) and PVI >16 identified DEX-induced hypotension (sensitivity 83%, specificity 64%).

CONCLUSIONS

PVI may predict DEX-induced changes in blood pressure in spontaneously breathing patients.

[Evaluation of the Effects of Remifentanil Doses on Hemodynamics and Perfusion Index at the Onset of Pneumoperitoneum during Laparoscopic Surgery]

BACKGROUND

The aim of this study was to investigate whether changes in perfusion index (PI) correlate with non-invasive haemodynamic parameters (HR, BP) following the onset of pneumoperitoneum under two doses (moderate-dose (MD) and high-dose (HD)) of remifentanil and to compare its reliability.

METHODS

We divided 33 patients who were scheduled for laparoscopic surgery under general anesthesia into two groups according to the dose of continuously infused remifentanil: moderate dose 0.5 μg x kg(-1) x min(1) (MD group, n = 16) and high dose 1.0 μg x kg(-1) x min(-1) (HD group, n = 17). Non-invasive blood pressure (NIBP), HR, and PI were measured before the start of surgery (time 1), after the start of surgery (time 2), before the start of pneumoperitoneum (time 3), and 1 min after the stable state of pneumoperitoneum (time 4).

RESULTS

PI decreased from the baseline after pneumoperitoneum in MD group, on the other hand PI did not change in HD group. Between the two groups, the magnitude of the PI changes was statistically different although MBP and HR were not statistically different

CONCLUSIONS

PI may be a reliable and easier alternative to conventional haemodynamic parameters for detection of stress response to pneumoperitoneum during remifentanil anaesthesia in adult patients.

Effects of remifentanil on the sphincter of Oddi in a 3-year-old child: a case report

Opioids cause spasm of the sphincter of Oddi. Remifentanil is metabolized enzymatically throughout the body. Its context-sensitive half-time is 3 to 4minutes. The effect of remifentanil on the sphincter of Oddi is unknown, especially in children. We recently encountered a patient in whom the administration of remifentanil caused spasm of the sphincter of Oddi, which resolved rapidly after discontinuation of remifentanil. A 3-year-old girl weighing 11.3kg was scheduled to undergo common bile duct excision with ductoplasty. Her diagnosis was congenital biliary dilatation. In the operating room, after achieving the initial induction through sevoflurane (5%) and intravenous rocuronium (10mg), she was intubated and administered a continuous paravertebral block by levobupivacaine (25mg/10mL +2.5mg/h). General anesthesia was maintained with sevoflurane (2%), remifentanil (0.5 μg kg(-1) min(-1)), and oxygen (fractional inspired oxygen tension, 0.33). The first intraoperative cholangiogram obtained via the cystic duct tube showed obstruction at the terminal end of the common bile duct. We injected scopolamine butylbromide (5mg, intravenous) to relax the sphincter of Oddi. However, the next cholangiogram obtained 3minutes later still showed an obstruction. We speculated that the obstruction may have been caused by remifentanil-induced spasm of the sphincter of Oddi. Therefore, we stopped administering remifentanil; 2minutes later, we achieved satisfactory passage of the contrast material to the duodenum. The predicted plasma concentrations of remifentanil at the time of stopping its administration and at the time of disobliteration were 6.38and 2.55ng/mL, respectively. The patient's postoperative course was uneventful. In patients who have spasms of the sphincter of Oddi during the administration of remifentanil, the resultant obstruction can be treated effectively by reducing the infusion rate of remifentanil.

Effect of fluid loading on left ventricular volume and stroke volume variability in patients with end-stage renal disease: a pilot study

Purpose

The aim of this study was to investigate fluid loading-induced changes in left ventricular end-diastolic volume (LVEDV) and stroke volume variability (SVV) in patients with end-stage renal disease (ESRD) using real-time three-dimensional transesophageal echocardiography and the Vigileo-FloTrac system.

Patients and methods

After obtaining ethics committee approval and informed consent, 28 patients undergoing peripheral vascular procedures were studied. Fourteen patients with ESRD on hemodialysis (HD) were assigned to the HD group and 14 patients without ESRD were assigned to the control group. Institutional standardized general anesthesia was provided in both groups. SVV was measured using the Vigileo-FloTrac system. Simultaneously, a full-volume three-dimensional transesophageal echocardiography dataset was acquired to measure LVEDV, left ventricular end-systolic volume, and left ventricular ejection fraction. Measurements were obtained before and after loading 500 mL hydroxyethyl starch over 30 minutes in both groups.

Results

In the control group, intravenous colloid infusion was associated with a significant decrease in SVV (13.8%±2.6% to 6.5%±2.6%, P<0.001) and a significant increase in LVEDV (83.6±23.4 mL to 96.1±28.8 mL, P<0.001). While SVV significantly decreased after infusion in the HD group (16.2%±6.0% to 6.2%±2.8%, P<0.001), there was no significant change in LVEDV.

Conclusion

Our preliminary data suggest that fluid responsiveness can be assessed not by LVEDV but also by SVV due to underlying cardiovascular pathophysiology in patients with ESRD.

[Efficacy of Ultrasound-guided Thoracic Paravertebral Block Compared with the Epidural Analgesia in Patients Undergoing Video-assisted Thoracoscopic Surgery]

BACKGROUND

Thoracic paravertebral block (TPVB) has proven to be safer by using ultrasound imaging. This prospective randomized study was designed to investigate postoperative pain relief and intraoperative hemodynamics in patients undergoing ultrasound-guided TPVB or epidural analgesia.

METHODS

Twelve patients scheduled for thoracoscopic surgery for lung cancer were randomly divided into two groups and received ultrasound guided TPVB (N=6) or epidural analgesia (N=6). Both groups received postoperative analgesia with continuous infusion of 0.2% ropivacaine 6 ml · hr(-1) via paravertebral or epidural block. Postoperative numeric rating score (NRS) and the data of intraoperative hemodynamics were collected.

RESULTS

In comparison with the epidural group, the level of NRS was higher in the TPVB group at 12 hr (4.5±1.05 vs 2.7±0.82, P<0.01), and 24 hr (4.5±1.05 vs 2.7±0.82, P<0.01) after surgery. In the TPVB group, the intraoperative amount of transfusion was smaller (1,331±147 ml vs 1,693±162 ml, P<0.01) and the lowest systolic pressure was higher (87±4.56 mmHg vs 73±4.34 mmHg, P<0.01) than that of the epidural group.

CONCLUSIONS

Ultrasound guided TPVB was performed affecting hemodynamics less than the epidural anesthetic. There was less postoperative analgesic effect on TPBV than on epidural analgesia after thora- coscopic surgery when continuously infusing 0.2% ropivacaine 6 ml · hr(-1).

Effect of fluid loading with normal saline and 6% hydroxyethyl starch on stroke volume variability and left ventricular volume

Purpose

The aim of this clinical trial was to investigate changes in stroke volume variability (SVV) and left ventricular end-diastolic volume (LVEDV) after a fluid bolus of crystalloid or colloid using real-time three-dimensional transesophageal echocardiography (3D-TEE) and the Vigileo-FloTrac™ system.

Materials and methods

After obtaining Institutional Review Board approval, and informed consent from the research participants, 22 patients undergoing scheduled peripheral vascular bypass surgery were enrolled in the study. The patients were randomly assigned to receive 500 mL of hydroxyethyl starch (HES; HES group, n=11) or normal saline (Saline group, n=11) for fluid replacement therapy. SVV was measured using the Vigileo-FloTrac system. LVEDV, stroke volume, and cardiac output were measured by 3D-TEE. The measurements were performed over 30 minutes before and after the fluid bolus in both groups.

Results

SVV significantly decreased after fluid bolus in both groups (HES group, 14.7%±2.6% to 6.9%±2.7%, P<0.001; Saline group, 14.3%±3.9% to 8.8%±3.1%, P<0.001). LVEDV significantly increased after fluid loading in the HES group (87.1±24.0 mL to 99.9±27.2 mL, P<0.001), whereas no significant change was detected in the Saline group (88.8±17.3 mL to 91.4±17.6 mL, P>0.05). Stroke volume significantly increased after infusion in the HES group (50.6±12.5 mL to 61.6±19.1 mL, P<0.01) but not in the Saline group (51.6±13.4 mL to 54.1±12.8 mL, P>0.05). Cardiac output measured by 3D-TEE significantly increased in the HES group (3.5±1.1 L/min to 3.9±1.3 L/min, P<0.05), whereas no significant change was seen in the Saline group (3.4±1.1 L/min to 3.3±1.0 L/min, P>0.05).

Conclusion

Administration of colloid and crystalloid induced similar responses in SVV. A higher plasma-expanding effect of HES compared to normal saline was demonstrated by the significant increase in LVEDV.

Target-controlled infusion and population pharmacokinetics of landiolol hydrochloride in patients with peripheral arterial disease

PURPOSE

We previously determined the pharmacokinetic (PK) parameters of landiolol in healthy male volunteers and gynecological patients. In this study, we determined the PK parameters of landiolol in patients with peripheral arterial disease.

METHODS

Eight patients scheduled to undergo peripheral arterial surgery were enrolled in the study. After inducing anesthesia, landiolol hydrochloride was administered at target plasma concentrations of 500 and 1,000 ng/mL for 30 minutes each. A total of 112 data points of plasma concentration were collected from the patients and used for the population PK analysis. A population PK model was developed using a nonlinear mixed-effect modeling software program (NONMEM).

RESULTS

The patients had markedly decreased heart rates at 2 minutes after initiation of landiolol hydrochloride administration; however, systolic blood pressures were lower than the baseline values at only five time points. The concentration time course of landiolol was best described by a two-compartment model with lag time. The estimates of PK parameters were as follows: total body clearance, 30.7 mL/min/kg; distribution volume of the central compartment, 65.0 mL/kg; intercompartmental clearance, 48.3 mL/min/kg; distribution volume of the peripheral compartment, 54.4 mL/kg; and lag time, 0.633 minutes. The predictive performance of this model was better than that of the previous model.

CONCLUSION

The PK parameters of landiolol were best described by a two-compartment model with lag time. Distribution volume of the central compartment and total body clearance of landiolol in patients with peripheral arterial disease were approximately 64% and 84% of those in healthy volunteers, respectively.

The dexmedetomidine concentration required after remifentanil anesthesia is three-fold higher than that after fentanyl anesthesia or that for general sedation in the ICU

Purpose

The general dexmedetomidine (DEX) concentration required for sedation of intensive care unit patients is considered to be approximately 0.7 ng/mL. However, higher DEX concentrations are considered to be required for sedation and/or pain management after major surgery using remifentanil. We determined the DEX concentration required after major surgery by using a target-controlled infusion (TCI) system for DEX.

Methods

Fourteen patients undergoing surgery for abdominal aortic aneurysms (AAA) were randomly, double-blindly assigned to two groups and underwent fentanyl- or remifentanil-based anesthetic management. DEX TCI was started at the time of closing the peritoneum and continued for 12 hours after stopping propofol administration (M0); DEX TCI was adjusted according to the sedation score and complaints of pain. The doses and concentrations of all anesthetics and postoperative conditions were investigated.

Results

Throughout the observation period, the predicted plasma concentration of DEX in the fentanyl group was stable at approximately 0.7 ng/mL. In contrast, the predicted plasma concentration of DEX in the remifentanil group rapidly increased and stabilized at approximately 2 ng/mL. The actual DEX concentration at 540 minutes after M0 showed a similar trend (0.54±0.14 [fentanyl] versus 1.57±0.39 ng/mL [remifentanil]). In the remifentanil group, the dopamine dose required and the duration of intubation decreased, and urine output increased; however, no other outcomes improved.

Conclusion

The DEX concentration required after AAA surgery with remifentanil was three-fold higher than that required after AAA surgery with fentanyl or the conventional DEX concentration for sedation. High DEX concentration after remifentanil affords some benefits in anesthetic management.

Population pharmacokinetics of olprinone in healthy male volunteers

BACKGROUND

Olprinone decreases the cardiac preload and/or afterload because of its vasodilatory effect and increases myocardial contractility by inhibiting phosphodiesterase III.

PURPOSE

The objective of this study was to characterize the population pharmacokinetics of olprinone after a single continuous infusion in healthy male volunteers.

METHODS

We used 500 plasma concentration data points collected from nine healthy male volunteers for the study. The population pharmacokinetic analysis was performed using the nonlinear mixed effect model (NONMEM®) software.

RESULTS

The time course of plasma concentration of olprinone was best described using a two-compartment model. The final pharmacokinetic parameters were total clearance (7.37 mL/minute/kg), distribution volume of the central compartment (134 mL/kg), intercompartmental clearance (7.75 mL/minute/kg), and distribution volume of the peripheral compartment (275 mL/kg). The interindividual variability in the total clearance was 12.4%, and the residual error variability (exponential and additive) were 22.2% and 0.129 (standard deviation). The final pharmacokinetic model was assessed using a bootstrap method and visual predictive check.

CONCLUSION

We developed a population pharmacokinetic model of olprinone in healthy male adults. The bootstrap method and visual predictive check showed that this model was appropriate. Our results might be used to develop the population pharmacokinetic model in patients.

[Case report of cardiac arrest during carotid body tumor resection]

We report a case of 30-second cardiac arrest that occurred during carotid body tumor resection due to the carotid sinus reflex. The patient was a 20-year-old man diagnosed with a carotid body tumor and scheduled for tumor resection. General anesthesia was induced and maintained with target controlled infusion of propofol. Analgesia was achieved with continuous administration of remifentanil. When the surgery was initiated, 1% lidocaine 3 ml was locally injected into the carotid bifurcation. When surgery was initiated in the neck region, the patient developed sudden cardiac arrest. Chest compression was immediately initiated, and atropine 0.5 mg was administered; subsequently circulation was restored. Surgery was resumed after placing a temporary pacemaker through the left subclavian vein. The surgery was successfully performed without any other bradycardia complications, and the patient recovered from general anesthesia without sequelae. Thus, the findings indicate the importance of considering the pacemaker placement before carotid body tumor resection.

Preoperative morphological analysis by transesophageal echocardiography and predictive value of plasma landiolol concentration during systolic anterior motion mitral valve repair : a report of three cases

We report three cases with systolic anterior motion (SAM) after mitral valve plasty. Preoperative mitral valve morphology is a risk factor for SAM. The morphological characteristics of SAM have been revealed in several studies. We found a small distance between coaptation and the interventricular septum in all cases, and cases 2, and 3 had a low AL/PL ratio, whereas case 3 had a large PML, which was revealed by transesophageal echocardiography. With the use of 3D transesophageal echocardiography, when mitral valve prolapse was investigated, in all three cases, it was easy to specify lesions. The issue for the future is 3D analysis when SAM is occurring.

[Intraoperative evaluation of visceral arteries by transesophageal echocardiography during aortic fenestration]

76-year-old man was diagnosed with DeBakey type IIIb acute aortic dissection, for which he underwent axillo-femoral bypass surgery. Two days postoperatively, hematochezia developed suddenly. Laboratory data revealed AST 5,088 IU x l(-1), ALT 3,822 IU x l(-1), and CK 27,746 IU x l(-1) suggesting intestinal malperfusion due to stenosis of the celiac artery (CEA) and superior mesenteric artery (SMA). The abdominal aorta and visceral arteries were evaluated by transesophageal echocardiography (TEE). Color Doppler imaging revealed increased blood flow velocity (4.0 m x sec(-1)) in CEA due to the stenosis, while that in SMA was decreased. Open abdominal aortic fenestration was performed. The aorta was clamped at the level of the infra-renal and inferior mesenteric arteries, and the septum between the false and true lumens was resected. On postoperative TEE assessment, CEA stenosis was resolved, and flow velocity was improved (3.0 m x sec(-1)). Color Doppler imaging demonstrated that fenestration resulted in recovery of SMA perfusion. Aortic fenestration is useful in the treatment of ischemic complications of aortic dissection. Its advantages include minimal invasiveness and short operative time. Bypass surgery and reoperation were avoided by evaluating visceral arteries by TEE in the case reported here.