Chih-Cherng Lu

Minimal low-flow isoflurane-based anesthesia benefits patients undergoing coronary revascularization via preventing hyperglycemia and maintaining metabolic homeostasis.

BACKGROUNDnThe objectives of this study were to determine whether minimal low-flow isoflurane-based anesthesia could be a feasible technique for patients undergoing coronary artery bypass graft surgery. It is hypothesized that isoflurane-based anesthesia facilitates an agreeable recovery from surgery is mediated through preventing hyperglycemia and metabolic disturbance associated with cardiopulmonary bypass.nnnMETHODSn107 consecutive patients were randomly assigned to two groups, i.e., isoflurane-based anesthesia group (n = 54) and fentanyl-based anesthesia group (control group, n = 53). In isoflurane-based anesthesia group, patients received isoflurane from induction up till departure from operating room to intensive care unit (ICU). In the control group, fentanyl (66.4 +/- 3.2 micrograms/kg) and midazolam (320 +/- 20 micrograms/kg) were administered to anesthetize the patients during the operation.nnnRESULTSnPatients with isoflurane-based anesthesia required less dopamine (0.6 +/- 0.2 vs. 4.2 +/- 0.4 micrograms/min) and dobutamine (0.4 +/- 0.2 vs. 4.1 +/- 0.5 micrograms/min); they could be extubated earlier (7.9 +/- 1.0 vs. 35.1 +/- 2.9 h), and had a shorter stay at ICU (2.2 +/- 0.2 vs. 4.8 +/- 0.4 days). In addition, occurrence of hyperglycemia (167 +/- 7.7 vs. 243 +/- 9.5 mg/dl) and bicarbonate requirement (128 +/- 7.0 vs. 313 +/- 22.0 mEq) were less in patients with isoflurane-based anesthesia as compared with those in fentanyl group.nnnCONCLUSIONSnThese results demonstrate that isoflurane, not fentanyl, benefits patients undergoing coronary artery bypass grafting surgery. This benefit perhaps is mediated through maintaining hemodynamic stability and metabolic homeostasis and preventing hyperglycemia.

Role of locus coeruleus and serotonergic drug actions on schedule-induced polydipsia.

Schedule-induced polydipsia (SIP) poses a general buffering property to reduce the heightened arousal produced by a schedule of intermittent feeding. It thus provides a unique opportunity to study CNS integration in stress-coping reactions. In the present study, we examined the role of the locus coeruleus (LC) and the pharmacological actions of serotonergic (5-HT2) analogs on SIP. Water intake, licking, and bar presses per minute in rats were recorded as indices of SIP activity after they had been subjected to 1-h performance of a fixed-interval 1-min operant pellet conditioning. Our results showed that SIP was progressively decreased after lesions were placed bilaterally in the LC areas and then followed by further lesioning in the bilateral ventral tegmental area. Neurotoxin DSP-4 also had an inhibitory action on the SIP potency. In addition, SIP was attenuated by 2,5-dimethoxy-4-iodoamphetamine (0.1, 0.5, or 1.0 mg/kg, IP), a 5-HT2 agonist, and activated by ritanserin (2.5 mg/kg, IP), a 5-HT2 agonist. After bilateral LC lesions, SIP was attenuated and the activating effect of RIT was abolished. Our data suggest that the LC is involved in the central integration of SIP and that the modulating effects of 5-HT2 receptors on SIP depend upon the integrity of LC function.

Eclampsia Following Cesarean Section with HELLP Syndrome and Multiple Organ Failure

We present a rare case of postpartum eclampsia with overt acute heart and renal failure, in the absence of any precursive signs of preeclampsia. A 41-year-old parturient underwent elective cesarean section for the delivery of twins under spinal anesthesia. Prior to the procedure, preoperative laboratory examination revealed only traceable proteinuria but she had hypertension perioperatively. Approximately 8 hours after the cesarean section, she developed seizures, followed by evident acute heart and renal failure. The diagnosis of postpartum eclampsia with HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome was established and she was admitted to the surgical intensive care unit for close care. Fortunately, the patient recovered fully and was discharged 26 days later. From this illustrative example, unexplainable and sustained hypertension following cesarean section should serve as a signal to warn the health care staff concerned about the possibility of impending life-threatening postpartum eclampsia.

Intrapleural Misplacement of a Thoracic Epidural Catheter in an Anesthetized Patient

Thoracic epidural analgesia provides adequate postoperative pain relief and favorable outcomes in major operations. However, a small number of devastating complications have been reported. Here we present a case of asymptomatic but potentially life-threatening intrapleural insertion of a thoracic epidural catheter intended for postoperative analgesia. A 39-year-old male diagnosed with esophageal carcinoma was scheduled for esophageal reconstruction. After induction of general anesthesia, a thoracic epidural catheter was inserted with a paramedian approach at the T8-9 interspace, using loss of resistance to ensure correct placement. The administration of a test dose of 2% lidocaine with epinephrine was unremarkable. After right thoracotomy, the epidural catheter was found in the right pleural cavity and was instantly removed. The patient underwent the operation smoothly and was discharged 10 days later without any sequelae. We recommend practitioners estimate the depth from the skin to the epidural space by computed tomography scan before operation and perform the placement of thoracic epidural catheter while the patient is awake to avoid accidental intrapleural misplacement.

Single Vital-capacity and Successive Tidal-volume Breathing of Sevoflurane in Induction of Anesthesia for Tracheal Intubation in Gynecologic Patients

BACKGROUNDnThe optimal end-tidal concentrations of sevoflurane in induction of anesthesia for tracheal intubation have been widely studied and discussed. Single vital-capacity breathing of a high concentration of inspiratory sevoflurane rapidly elevates the end-tidal concentration to cause loss of consciousness, although it does not bear relation to proportional body or brain uptake. This study was designed to investigate the time effect of fast wash-in of alveolar sevoflurane in induction of anesthesia for tracheal intubation with single vital-capacity and ensuing tidal-volume breathing in gynecologic patients.nnnMETHODSnThirty-six ASA I-II patients undergoing gynecologic surgeries under general anesthesia were included in the study. Prior to anesthesia, they were instructed on the vital capacity technique for induction with prior primed 7.2% inspiratory sevoflurane in 6 L/min oxygen in the breathing circuit. Immediately after loss of consciousness, assisted ventilation with fixed 3.5% sevoflurane in oxygen was applied to patients in groups 1 and 2 for 3 minutes, and for 4.5 minutes in group 3. Patients in group 2 received fentanyl 1.5 mug/kg before induction. In all patients, tracheal intubation was performed following succinylcholine 1.5 mg/kg. Inspiratory and end-tidal concentrations of sevoflurane, blood pressure and heart rate were recorded.nnnRESULTSnAll patients achieved vital capacity induction uneventfully, of whom two-thirds needed a second or third breath. The induction time was 60.6 +/- 19.2 seconds and could be reduced to 48.3 +/- 17.9 seconds with fentanyl pretreatment. The end-tidal concentration of sevoflurane was 2.68 +/- 0.20% after 4.5 minutes of ventilation with 3.5% sevoflurane, at which concentration the intubation-induced hemodynamic responses could not be suppressed.nnnCONCLUSIONnThis study demonstrated that vital-capacity induction with a high concentration of sevoflurane is a safe and feasible technique for our female patients. The end-tidal 1.5 minimum alveolar concentration sevoflurane following 4.5 minutes of tidal-volume ventilation did not suppress intubation-induced hemodynamic responses. Pretreatment with fentanyl helped to shorten the induction time and provide better hemodynamic control for tracheal intubation.

Lower Body Negative Pressure–Induced Vagal Reaction: Role for the Osmopressor Response?

BACKGROUNDnWater ingestion elicits an osmopressor response in patients with impaired baroreflexes. In young, healthy subjects, water elicits sympathetic vasoconstriction. This study investigated the effect of water on the lower body negative pressure (LBNP)-induced vasovagal reaction and also analyzed its effect on the change of regional cerebral blood flow during LBNP.nnnMETHODSnTwelve young healthy subjects underwent LBNP (40 mm Hg) tolerance testing for 45 minutes or until presyncopal symptoms occurred. Subjects received either LBNP or no LBNP with or without prior water ingestion. The severity of vasovagal reaction was determined by participant self-report rating of orthostatic symptoms during the LBNP test. Changes of regional cerebral blood flow (rCBF) between LBNP and water ingestion with LBNP groups were assessed using statistical parametrical mapping analyses.nnnRESULTSnWater ingestion attenuated the severity of symptomatic scores during LBNP (P = 0.004). Water ingestion increased Total peripheral vascular resistance (P < 0.001) and attenuated the blood pressure drop (P < 0.001) at the cessation of study. LBNP decreased rCBF over the left superior prefrontal gyrus, limbic-parahippocampal gyrus, left sublobar-caudate body, and hypothalamus (P < 0.001). Water increased rCBF significantly over the right frontal lobe, including the inferior and medial prefrontal gyrus, subcallosal, and sublobar insula, during LBNP stimulation (P < 0.001).nnnCONCLUSIONSnWater ingestion strongly reduces symptomatic burden of the vasovagal reaction induced by LBNP stimulation. The cortical activation of limbic and prefrontal cortex likely indicates the involvement of osmopressor response in central autonomic cardiovascular physiology. The central cortical activation of osmopressor response might provide insight into the mechanisms by which water ingestion reduces the vasovagal reaction.

Isoflurane compared with fentanyl-midazolam-based anesthesia in patients undergoing heart transplantation: A retrospective cohort study.

AbstractInhalation anesthetics provide myocardial protection for cardiac surgery. This study was undertaken to compare the perioperative effects between isoflurane and fentanyl-midazolam-based anesthesia for heart transplantation. A retrospective cohort study was conducted by reviewing the medical records of heart transplantation in a single medical center from 1990 to 2013. Patients receiving isoflurane or fentanyl-midazolam-based anesthesia were included. Those with preoperative severe pulmonary, hepatic, or renal comorbidities were excluded. The perioperative variables and postoperative short-term outcomes were analyzed, including blood glucose levels, urine output, inotropic use, time to extubation, and length of stay in the intensive care units. After reviewing 112 heart transplantations, 18 recipients with fentanyl-midazolam-based anesthesia, and 29 receiving isoflurane anesthesia with minimal low-flow technique were analyzed. After cessation of cardiopulmonary bypass, recipients with isoflurane anesthesia had a significantly lower mean level and a less increase of blood glucose, as compared with those receiving fentanyl-based anesthesia. In addition, there was less use of dobutamine upon arriving the intensive care unit and a shorter time to extubation after isoflurane anesthesia. Compared with fentanyl-midazolam-based anesthesia, isoflurane minimal low-flow anesthesia maintained better perioperative homeostasis of blood glucose levels, less postoperative use of inotropics, and early extubation time among heart-transplant recipients without severe comorbidities.

Awakening arterial blood and end-tidal concentrations of isoflurane in female surgical patients.

AbstractDelayed extubation occurs after isoflurane anesthesia, especially following prolonged surgical duration. We aimed to determine the arterial blood concentrations of isoflurane and the correlation with end-tidal concentrations for predicting emergence from general anesthesia.Thirty-four American Society of Anesthesiologists physical status class I–II gynecologic patients were included. General anesthesia was maintained with a fixed 2% inspiratory isoflurane in 6u200aL/minute oxygen, which was discontinued after surgery. One milliliter of arterial blood was obtained for the determination of isoflurane concentration by gas chromatography at 20 and 10 minutes before and 0, 5, 10, 15, and 20 minutes after discontinuation, in addition to the time of eye opening to verbal command, defined as awakening. Inspiratory and end-tidal concentrations were simultaneously detected by an infrared analyzer.The mean awakening arterial blood concentration of isoflurane was 0.20%, which was lower than the simultaneous end-tidal concentration 0.23%. The differences between arterial and end-tidal concentrations during emergence fell into an acceptable range (±1.96 standard deviation). After receiving a mean time of 108-minute general anesthesia, the time to eye opening after discontinuing isoflurane was 18.5 minutes (range 11–30, median 18 minutes), without statistical significance with anesthesia duration (Pu200a=u200a0.078) and body mass index (Pu200a=u200a0.170).We demonstrated the awakening arterial blood concentration of isoflurane in female patients as 0.20%. With well-assisted ventilation, the end-tidal concentration could be an indicator for the arterial blood concentration to predict emergence from shorter duration of isoflurane anesthesia.

Clearance of meperidine and its metabolite normeperidine in hemodialysis patients with chronic noncancer pain.

CONTEXTnNormeperidine accumulates in patients with impaired renal function and may cause central neurotoxicity. However, some uremic patients still undergo meperidine treatment for chronic pain.nnnOBJECTIVESnTo prevent normeperidine side effects and complications, we investigated the clearance rate and extraction ratio of meperidine and normeperidine in hemodialysis patients with chronic pain.nnnMETHODSnThree hemodialysis patients, with diagnoses of chronic pancreatitis, chronic back pain, and intractable intra-abdominal pain, received long-term (more than six months) administration of meperidine for chronic noncancer pain. During regular hemodialysis, 72 blood samples in total were collected from the afferent port, efferent port, and ultradiafiltrate port at eight time points. The plasma concentrations of meperidine and normeperidine were determined by high-performance liquid chromatography.nnnRESULTSnThe prehemodialysis plasma concentrations of meperidine and normeperidine were 2963xa0±xa0315 and 2369xa0±xa01974xa0ng/mL, which declined to 591xa0±xa0109 and 853xa0±xa0765xa0ng/mL, with 80% and 65% reduction, respectively. The plasma clearance and extraction ratios of meperidine were 22.7xa0±xa09.8xa0mL/minute and 10.1xa0±xa05.6% and for normeperidine 26.0xa0±xa011.4xa0mL/minute and 10.8xa0±xa02.5%, respectively.nnnCONCLUSIONnHemodialysis can efficiently remove meperidine and its active metabolite, normeperidine, in uremic patients receiving long-term meperidine therapy for chronic noncancer pain.

Early recognition of an entrapped pulmonary artery catheter by blood leaking into the syringe and thermistor connector during cardiac surgery

An 84-year-old male was scheduled for coronary artery bypass graft surgery under general anesthesia. During cardiopulmonary bypass, the leakage of blood into the syringe being used for balloon inflation and the thermistor connector of the pulmonary artery catheter (PAC) was detected. Resistance was encountered when trying to withdraw the PAC. A surgical suture of the right atrium cannulation was stitched to PAC and was immediately released. Early detection of surgical damage to PAC and recognition of the entrapped PAC by gently withdrawing it avoided possible life-threatening complications, including pulmonary air embolism, and the inevitable of resternotomy. Transesophageal echocardiography, chest radiography, and fluoroscopy can help confirm any postoperative surgical damage following closure of the sternum or while in the intensive care unit.