Biomedical subjects

S M Lin

Publications and source records attributed to S M Lin.

At least 55 records · Page 3Linked to original sources

PubMed1998

Right ventricular dysfunction after tetralogy repair in a pediatric patient with successful ECMO support--a case report.

Right ventricular dysfunction after surgical repair of tetralogy is a serious life threatening complication. Although pulmonary vasodilators and inotropes can be used for cardiac support in tetralogy repair, these drugs may be ineffective in some patients. To date extracorporeal membrane oxygenation (ECMO) support may be used effectively in these patients when medical therapy fails. We report a case with successful ECMO support in right ventricular dysfunction and pulmonary hypertension after total surgical correction of Fallot's tetralogy. ECMO circuit was instituted in the operating room due to difficulty in weaning from cardiopulmonary bypass in spite of aggressive medical therapy. We reviewed and discussed the indications, contraindications of application of ECMO and patient survival with treatment of ECMO. At the same time we wish to share our limited experience we gained in our first attempt of ECMO support.

Extracorporeal Membrane Oxygenation↗

PubMed1998

The neuromuscular effects of mivacurium in adults with priming technique during nitrous oxide-fentanyl anesthesia: a randomized comparative study with succinylcholine.

BACKGROUND: We investigated the neuromuscular effects of equipotent dose (3 x ED90) of mivacurium either given as a single bolus or under the influence of priming technique, comparing with that of succinylcholine in adults undergoing elective surgery during nitrous oxide-narcotic anesthesia. METHODS: Sixty ASA class I patients of either sex with age between 16 to 49 years were randomly assigned to 3 groups for a trial of mivacurium under nitrous oxide-narcotic anesthesia. Group I (non-priming group, n = 20) received mivacurium 0.25 mg/kg straight as a single intubating dose; Group II (priming group, n = 20) received an intubating dose of 0.225 mg/kg mivacurium which was preceded by 0.025 mg/kg 3 min earlier; and Group III received an intubating bolus of succinylcholine 1 mg/kg. Thenar electromyogram response to supramaximal train-of-four stimulation of the ulnar nerve at 12-s intervals was used to determine neuromuscular blockade. Blood pressure and heart rate were recorded before and at 1-min interval for 3 min after injection of drugs. Data were presented as mean +/- standard deviation. P value < 0.05 was considered statistically significant. RESULTS: The onset time of mivacurium was accelerated by priming procedure in comparison with the nonpriming technique (2.0 min vs. 2.7 min), but it was much slower than that of succinylcholine (0.8 min). The priming procedure did not influence the duration of action or recovery. Side effects of mivacurium, such as cutaneous flushing and hypotension, were minimal at this dose in our patients. CONCLUSIONS: Priming technique (with 10% of the total dose as the priming dose, and 3 min as the priming interval) can hasten the onset of mivacurium in adults during nitrous oxide-narcotic anesthesia without influencing the duration of action and recovery time.

Adolescent↗

PubMed1998

Thyrotropin-secreting pituitary adenoma.

Thyrotropin (TSH)-secreting pituitary adenoma (TSPA) is a rare cause of hyperthyroidism and detailed reports of this entity in Taiwan are uncommon. We report a patient with TSPA with symptoms of hyperthyroidism and describe the presentation, endocrine and histologic findings, and treatment. The patient, a 42-year-old man, presented with a 2-year history of weight loss, palpitation, anxiety, and bad temper. He had increased basal serum thyroxine (T4, 18.3 micrograms/dL) and triiodothyronine (T3, 250 ng/dL) concentrations. The TSH concentration was normal (4.6 microIU/mL) and showed impaired response to stimulation by TSH-releasing hormone. Tests for antithyroid antibodies were negative. Thyroid scintigraphy showed mild thyroid enlargement. The thyroid uptake of radioactive iodine (131I) was high at 2 hours (34%) and 24 hours (63%) after 131I administration. Other serum hormone concentrations were within normal limits. Magnetic resonance imaging of the brain showed a microadenoma in the pituitary region. Octreotide and bromocriptine tests showed 78.4% and 58.3% inhibition of TSH, respectively. The patient underwent trans-sphenoidal pituitary tumor excision, and the symptoms of hyperthyroidism subsided after surgery. Six months after the operation, there was no evidence of recurrence of the tumor or symptoms of hyperthyroidism. Hormonal supplements were also not necessary. In conclusion, TSPA is a rare cause of hyperthyroidism. However, in patients with symptoms of hyperthyroidism and increased basal serum T1 and T3 concentrations, but normal or even elevated serum TSH concentrations, TSPA should be considered in the differential diagnosis.

Adenoma↗

PubMed1997

Surgical treatment of thoracic arachnoiditis with multiple subarachnoid cysts caused by epidural anesthesia.

We report on a 36 year-old woman who had sensorimotor and sphincter dysfunction 0.5 day after having an epidural anesthesia to deliver her baby. The patients' neurological deficits recovered gradually and she could walk without support 1.5 months after the operation. However, her neurological function deteriorated 4 months after anesthesia and a magnetic resonance imaging (MRI) study revealed spinal arachnoiditis with multiple subarachnoid cysts at the T5-7 levels. Surgical treatment consisted of lysis of adhesions and wide opening of the subarachnoid cysts. Her motor function improved after operation and she could walk without support after a 1 year follow-up. However, her sphincter and sensory abnormalities persisted for the most part. The literature on the surgical treatment of arachnoiditis with myelopathy is reviewed and the surgical indications are discussed.

Adult↗

PubMed1997

Response of patients with dual hepatitis B virus and C virus infection to interferon therapy.

Patients with dual infection with hepatitis B virus (HBV) and delta virus (HDV) responded poorly to interferon (IFN) therapy. Little is known about the effect of IFN therapy in patients with HBV and hepatitis C virus (HCV) dual infection. The patients in two randomized controlled trials with chronic HBV infection were retrospectively assayed for HCV markers. The HBV responses to IFN therapy in patients with and without HCV markers were compared. An open trial was conducted in 4 patients who had lost their serum HBV surface antigen (HBsAg) but had continuing HCV viremia and hepatitis. Of the 15 patients seropositive for HCV marker(s), only 1 (6.7%) responded with seroclearance of HBV DNA and HBV e antigen, as compared with 46 (28%) of 164 HCV-negative patients (p = 0.058). Icteric hepatitis developed in 1 patient on emergence of serum HCV RNA in association with seroclearance of HBV DNA. In contrast, good response was demonstrated in 3 of the 4 patients who had lost serum HBsAg before therapy. The results suggest that IFN therapy is not only of limited value in patients with dual infection with HBV and HCV but also has a potential risk of severe hepatitis if the clearance of one virus removes its suppressive effect on and facilitates the emergence of the other. However, patients with continuing HCV hepatitis after termination of the chronic HBsAg carrier state responded well to IFN therapy.

Adult↗

PubMed1997

Induction of antitumor immunity by intracerebrally implanted rat C6 glioma cells genetically engineered to secrete cytokines.

To test whether cytokine gene therapy can be applied to an immunologically privileged site, such as the brain, we investigated antitumor immunity in the brain induced by cytokine-secreting glioma cells. Three cytokine genes, interleukin-2 (IL-2), interleukin-4 (IL-4), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were transduced into a rat C6 glioma cell line via a retroviral vector, S2. Rats intracerebrally (IC) implanted with the C6 cells genetically engineered to secrete the cytokines, especially GM-CSF, manifested significantly higher survival rates than those with C6 cells or with C6 cells bearing the control vector (p < 0.002). In vivo, C6 tumors bearing the cytokine genes grew more slowly than wild-type tumors at any time point, and eventually diminished within 6 weeks after tumor cell implantation. Histopathological and immunohistochemical studies revealed that different cytokines induced diverse immune reactions. In the IL-2 group, CD4+ and CD8+ T cells dominated from day 3 to week 4, but disappeared at week 6. Some granulocytes were noted between weeks 2 and 4. In the IL-4 group, eosinophils were noted from day 3 to week 4, and CD4+ and CD8+ T cells, as well as macrophages at week 2. At week 6, only residual levels of macrophages and CD8+ T cells remained. In the GM-CSF group, granulocytes appeared as early as day 1 post-IC tumor implantation, and macrophages at day 2. CD4+ and CD8+ T cells were found from day 3 to week 4. At week 6, only residual CD4+ T cells and macrophages remained. Long-lasting antitumor immunity was confirmed in all groups by rechallenging surviving rats with wild-type C6 cells in the brain 100 days after implanting cytokine gene-bearing C6 cells. In vivo depletion of GM-CSF by anti-GM-CSF antibody further confirmed that the immune reaction induced by GM-CSF-secreting tumor cells were mainly from the action of GM-CSF, rather than the immunogenicity of C6 cells.

Animals↗

PubMed1997

Non-surgical treatment of hepatocellular carcinoma.

A decade ago, surgery was the only satisfactory treatment modality for hepatocellular carcinoma (HCC), but it was limited only to selected cases. For the majority of cases of HCC, systemic chemotherapy was one of the few treatment alternatives, but provided only marginal benefit. In the past 20 years, diagnostic methods have improved to an extent that small HCC less than 1 cm can be detected. Moreover, non-surgical treatment is available, of which regional therapy has been shown to prolong patients' survival, and may even replace surgical resection in some cases. Regional therapy is indicated for the treatment of HCC when there is no extrahepatic metastasis and the patient has adequate liver function reserve, thus permitting repeated therapy. Transcatheter hepatic arterial embolization (TAE) using various embolizers has been well documented to include controlled studies. However, it is not indicated for patients with thrombosed main portal veins. Its therapeutic effect is also doubtful when the tumour is infiltrative in nature or is hypovascular, too large or too small. Additional chemotherapeutic agents mixed into the embolizer with lipiodol and degraded starch microspheres or styrene-maleic acid-neocarzinostatin in which chemotherapeutic agents are embedded, are used with a better response, but the survival rate has not shown significant improvement. Ultrasound-guided local injection therapy is another new method of treatment of HCC. Of these techniques, percutaneous ethanol injection therapy (PEIT) is widely used with excellent results for small, encapsulated tumours in livers with less than three HCC. Percutaneous ethanol injection therapy can also be used in cases with portal vein thrombosis, but it is not suitable for patients having coagulopathy or ascites. Using acetic acid, OK-432, interferon or anti-cancer drugs in the injection therapy shows no further benefit over ethanol alone. Transcatheter echoguided thermotherapy or cryotherapy has been reported in small series of patients, as has target therapy with immune or radiotherapy and conformal radiotherapy. Preliminary studies show encouraging results. Systemic therapy with either single drug or multidrugs is ineffective, with a response rate of less than 20%. Immunotherapy, such as with interferon or other cytokines, is not beneficial. Hormone therapy has not been promising, except for treatment with tamoxifen, which has been reported to show some beneficial effect. Gene therapy is still in its infancy. In summary, recent progress in non-surgical treatment of HCC has resulted in a breakthrough of regional therapy looking quite promising. Moreover, a combination of different types of regional therapies may yield better outcomes in selected individuals.

Antineoplastic Agents↗

PubMed1997

Priming technique accelerates the onset time of mivacurium in children during halothane anesthesia.

BACKGROUND: Mivacurium is considered a relaxant suitable for tracheal intubation in children due to its rapid onset. We compared the neuromuscular effects of mivacurium, with and without priming, in children undergoing elective surgery during halothane anesthesia. METHODS: Forty pediatric patients (2-10 yr, ASA class I) were randomly into 2 groups and studied under halothane anesthesia. The non-priming group (n = 20) received mivacurium 0.25 mg/kg, and the priming group (n = 20) received a priming dose of mivacurium 0.025 mg/kg, followed by an intubating dose of 0.225 mg/kg 3 min later. Thenar Electromyogram responsive to supramaximal train-of-four stimulation of the ulnar nerve at 12 s intervals was used as neuromuscular monitoring. RESULTS: The onset time in the priming group was significantly faster than in the non-priming group (1.04 min vs. 1.7 min). The mean time from injection of intubating dose to spontaneous recovery to 25%, 50% and 75% twitch were not influenced by priming technique. Side effects, such as cutaneous flushing and hypotension, were unremarkable at this dose in children. CONCLUSIONS: Priming technique can significantly accelerates the onset of mivacurium in the pediatric patients under halothane anesthesia.

Anesthesia, Inhalation↗

PubMed1997

Disseminated miliary cerebral candidiasis.

We present a case of disseminated intracranial infection by Candida albicans in a 5-year-old girl who had fever and a change of consciousness after surgery for complex congenital heart malformation. MR imaging revealed multiple small ring-enhancing hemorrhagic abscesses. One year after antifungal treatment, the abscesses and ventriculomegaly were almost completely resolved. The patient was discharged in a stable but vegetative condition.

Amphotericin B↗

PubMed1996

Measurement of motor conduction in the thoracolumbar cord. A possible predictor of surgical outcome in cervical spondylotic myelopathy.

STUDY DESIGN: A prospective motor-evoked potential study with measurement of spinal cord motor conduction velocity in the thoracolumbar cord was performed before and after decompression surgery in 30 patients with cervical spondylotic myelopathy. OBJECTIVES: To evaluate the neurofunctional integrity of the spinal motor pathways in cervical spondylotic myelopathy in patients compared with age-matched control subjects; to assess any changes after posterior surgical decompression; and to correlate such changes with functional outcomes so that the predictability of preoperative motor-evoked potentials could be determined. SUMMARY OF BACKGROUND DATA: Previous studies evaluating neurologic function and predictability of surgical results in cervical spondylotic myelopathy patients always depended on the morphologic changes of the cord and spinal structures. The recently developed motor-evoked potential study and noninvasive measurement of spinal cord motor conduction velocity may provided an objective method to evaluate physiologic motor function in cervical spondylotic myelopathy patients. METHODS: Spinal cord motor conduction velocity in the thoracolumbar cord was measured using percutaneous magnetic stimulation over the motor cortices and F-wave studies in median and peroneal nerves. Motor function of cervical spondylotic myelopathy patients was graded according to evaluation of signs of cord involvement, ambulation, and degree of dependence in activities of daily living. Evaluation was performed at 6 months, 1 year, and 2 years after decompression surgery. RESULTS: Motor functional improvement accompanied by increased spinal cord motor conduction velocity occurred in Grade I patients with a mild neurologic dysfunction but not in Grade II or III patients with a moderate-to serve neurologic deficit. Neurologic improvement does not appear to occur until 6 months after surgery. CONCLUSIONS: Measurement of spinal cord motor conduction velocity may provide an objective and quantitative approach to assessing the motor functional integrity of the spinal cord and serving as a predictor in evaluating surgical outcome in patients with cervical spondylotic myelopathy.

Aged↗

PubMed1996

Primary hemangiopericytoma in the axis bone: case report and review of literature.

OBJECTIVE AND IMPORTANCE: To the best of our knowledge, this is the first reported case of primary hemangiopericytoma in the axis bone. With this report, we attempt to better characterize this uncommon lesion in the vertebral column. CLINICAL PRESENTATION: This report describes a case of primary heman-giopericytoma in the axis bone of a 16-year-old female patient who presented with acute torticollis. Her neurological status was unimpaired. A lateral radiograph of the cervical spine demonstrated an odontoid neck fracture and a C1-C2 rotatory deformity. The magnetic resonance imaging study showed a hypodense lesion with moderate enhancement on T1- and T2-weighted images on the dens and body of the axis with an odontoid neck fracture. Reviewing the literature, primary hemangiopericytoma in the spine is rare; 9 cases of hemangiopericytoma with vertebral bone involvement and 44 cases of this tumor with intraspinal meningeal involvement have been reported. INTERVENTION: The patient was treated with odontoidectomy via the transoral approach, along with posterior fixation using the Halifax clamp. She was followed up 17 months after surgery, and no evidence of tumor recurrence was found. CONCLUSION: The treatment for osseous hemangiopericytoma is still controversial. At present, adequate surgical removal with postoperative radio-therapy is recommended. In addition, although hemangiopericytoma is rare in the spine, it should be kept in mind in the differential diagnosis of spinal tumors.

Adolescent↗

PubMed1996

Severe clinical rebound upon withdrawal of corticosteroid before interferon therapy: incidence and risk factors.

To analyse the incidence and risk factors of clinical rebound and hepatic decompensation during or upon withdrawal of prednisolone pretreatment before interferon (IFN) therapy, two series of Taiwanese patients with chronic viral hepatitis from two independent randomized controlled trails were compared. Group 1 included 41 patients with chronic hepatitis B who were pretreated with daily prednisolone (30 mg) for 3 weeks, 15 mg for 1 week and no prednisolone for 2 weeks prior to lymphoblastoid IFN therapy. Group 2 consisted of 59 patients with chronic hepatitis B who were pretreated with daily prednisolone (40 mg) for 2 weeks, 30 mg prednisolone for 2 weeks, 20 mg prednisolone for 2 weeks and no prednisolone for 2 weeks prior to INF alpha-2a therapy. Clinical rebound developed more frequently in group 2 (67.8%) than in group 1 patients (41.5%; P < 0.01). The peak serum transaminase levels of group 1 and 2 patients during clinical rebound were similar. Icteric and symptomatic clinical rebound occurred in four (one cirrhotic) group 2 patients. The incidence of hepatic decompensation was 3.4% in group 2 patients, or 5.0% in group 2 patients with clinical rebound. Patients pretreated with a higher dose (40 mg) of prednisolone (odds ratio 3.0; 95% CI 1.3-6.6; P < 0.01) and non-cirrhotic patients (odds ratio 6.2; 95% CI 1.2-32.1; P < 0.02) tended to suffer from clinical rebound more frequently. However, once clinical rebound develops in cirrhotic patients, the relative risk of decompensation is 16 times that of non-cirrhotic patients. These results suggest that clinicians should be cautious in prescribing a short course of corticosteroids for patients with chronic viral hepatitis, because hepatic decompensation might occur in Oriental people with or without cirrhosis.

Adult↗

PubMed1995

Lack of effect of flumazenil on the reversal of propofol anaesthesia.

Propofol, like the benzodiazepines, activates the GABAA receptor-chloride ionophore complex; they potentiate one another. Since neither pharmacodynamic nor pharmacokinetic data concerning drug interaction between flumazenil and propofol is available, and especially considering the relationship of binding sites, flumazenil, the antagonist of benzodiazepines, was investigated to determine its effect upon recovery from propofol anaesthesia. Forty women receiving dilatation and curettage procedures were included in this double-blind test. After 50 micrograms fentanyl, propofol 2 mg.kg-1 was injected for induction and followed by infusion at the rate of 15 mg.kg-1.hr-1. After the operation, patients were given normal saline (Group A) or flumazenil 10 micrograms.kg-1 (Group B) randomly. Recovery time in Group A was 15.2 +/- 5.1 min and Group B 15.8 +/- 4.8 min. Propofol concentrations at the end of infusion were 4.17 +/- 1.33 micrograms.ml-1 (Group A) and 4.03 +/- 1.45 micrograms.ml-1 (Group B); these then declined to 1.22 +/- 0.17 micrograms.ml-1 (Group A) and 1.18 +/- 0.15 micrograms.ml-1 (Group B) when patients were able to open their eyes on command. No significant differences were found between the groups based on propofol concentrations and recovery time, nor did haemodynamic changes differ between them after administration of reversal agents. It was concluded that flumazenil 10 micrograms.kg-1 does not influence recovery from propofol anaesthesia.

Adult↗

PubMed1995

Initiator elements and regulated expression of the herpes simplex virus thymidine kinase gene.

Regulated expression of thymidine kinase mRNA in herpes simplex virus mutants harboring thymidine kinase promoters that lacked functional TATA boxes was largely unaffected by additional sequence alterations around the transcriptional start site. A strong initiator element increased the regulated expression of a TATA-containing promoter by 50% but did not affect that of the TATA-less promoter. Thus, initiator elements exert only small effects in this promoter context.

Animals↗

PubMed1995

Continuous, on-line, real-time spectral analysis of SAP signals during cardiopulmonary bypass.

We communicated the application of continuous, on-line, real-time power spectral analysis of systemic arterial pressure (SAP) signals during cardiopulmonary bypass when the heart was functionally but reversibly disconnected from the blood vessels. Based on observations from 15 cases of successfully completed coronary artery bypass grafting procedures, we found that the very low (0.00-0.08 Hz), low (0.08-0.15 Hz)-, high (0.15-0.25 Hz)-, and very high (0.80-1.60 Hz) frequency components of SAP signals exhibited differential changes before, during, and after cardiopulmonary bypass. In particular, the very low-frequency component, which purportedly represents the contribution of vasomotor activity to SAP, presented only a mild decrease in power during hypothermic cardioplegia. Interestingly, the total peripheral resistance also manifested only a slight reduction during the same period. On the other hand, the low-, high-, and very high frequency components were essentially eliminated. These results unveiled an active role for the blood vessels in the maintenance of SAP during cardiopulmonary bypass, possibly as a result of a maintained vasomotor tone as reflected by the sustained very low frequency component of the SAP signals.

Aged↗

PubMed1995

Intraoperative monitoring of motor function by magnetic motor evoked potentials.

Under etomidate anesthesia, motor evoked potentials produced by magnetic stimulation were successfully recorded from 10 thenar muscles and 10 anterior tibial muscles of eight patients who had undergone surgery on the medulla oblongata and the cervical and thoracic spinal cords. Recordings taken before placing the neural tissue at risk were assessed for variability in amplitude and latency. The lower limit in amplitude was approximately one-third (25-43%) of the baseline. The latencies were more difficult to monitor than were the amplitudes. The latency variations were 2.56 +/- 0.50 milliseconds for the hand and 6.84 +/- 1.37 milliseconds for the leg. During surgery, the unilateral recordings of two patients were transiently lost but partially recovered after a pause in the operation. No obvious postoperative weaknesses in the corresponding limbs occurred. One patient, who showed a permanent loss of unilateral recording, had transient monoplegia with a complete recovery. None of the remaining five patients who had amplitudes larger than one-third of the baseline at the end of the operation had additional motor deficits. Our conclusions are that under etomidate anesthesia, the magnetic motor evoked potentials can be convenient and reliable monitors of motor function, that changes in the amplitude may be superior to those in the latency for intraoperative warning, that the criterion for potential neural damage under magnetic motor evoked potential monitoring might be an amplitude reduction of two-thirds of the control value, and that the magnetic stimulation seems to be more sensitive than the electrical stimulation in the monitoring of motor function and also allows more time and opportunities for the motor function to recover.

Adolescent↗

PubMed1995

The effect of intrathecal bupivacaine with combined fentanyl in cesarean section.

BACKGROUND: The use of neuraxial opioids has gained popularity over the last few years; they may augment the analgesia produced by the local anesthetic through direct binding with the specific spinal receptors. Morphine, a lipophobic opioid, may not be optimal as an intrathecal drug for intraoperative analgesia because of its slow onset. The lipophilic opioid, fentanyl for instance, if administered intrathecally, its onset is fast and many of its merits by virtue of its lipophilic property may be seen intraoperatively. METHODS: Seventy five healthy pregnant women who sustained cesarean section under spinal anesthesia were assessed in a randomized fashion. The spinal anesthetic used was 0.5% hyperbaric bupivacaine. Patients were divided into 5 groups, 15 in each group. Fentanyl 0 (Group I), 7.5 (Group II), 10 (Group III), 12.5 (Group IV) and 15 (Group V) micrograms was respectively added to normal saline to make a total volume of 0.3 ml, which was then added to bupivacaine and administered to patients in a randomized fashion. The effect of analgesia, vital signs and side effects were observed every 5 min during operation and every 30 min after operation. RESULTS: It was disclosed that all patients in group V and IV had excellent analgesia intraoperatively, while only 33.3% patients in the control group had an analgesia which was qualified as excellent. Complete analgesia (time from injection to first report of pain) also lasted longer in group IV (201.3 +/- 16.4 min, mean +/- SEM) and group V (210.3 +/- 18.6 min) compared with group I (118.9 +/- 10.4 min). The duration of effective analgesia (time from injection to first parental opioid) was increased with the dose of intrathecal fentanyl above 12.5 micrograms (293 +/- 22.4 min). Both complete analgesia and effective analgesia were not significantly different between group IV and group V. Pruritus was the most common side effect. The incidence of shivering decreased significantly in group IV & V as compared with control group. CONCLUSIONS: The combination of bupivacaine with a dose of fentanyl as low as 7.5 micrograms did not produce actual clinical effects. As the dose of fentanyl was increased to 12.5 micrograms or 15 micrograms the quality of surgical analgesia was better and the postoperative analgesia lasted longer. It seemed that the clinical effect might reach its ceiling at the dose of 12.5 micrograms. Pruritus was the most common side effect, but it was mild.

Adult↗

PubMed1995

Power spectral analysis of systemic arterial pressure signals during open heart surgery.

BACKGROUND: The close relationship between the balance of sympathetic and parasympathetic tones and the results of power spectral analysis (PSA) of systemic arterial pressure (SAP) has been suggested recently. The purpose of this study was to further describe the changes of balance between the two autonomic nervous components during open heart surgery for coronary arterial disease (CAD) or valvular heart disease (VHD) with the PSA technique of SAP. METHODS: By relaying the SAP signals to a personal computer utilizing a power spectral analysis algorithm, radial arterial pressure signals of 27 patients (11 with CAD for coronary artrial bypass graft, as CAD groups; 16 with VHD, as VHD group, including 8 for aortic valve replacement and 8 for mitral valve replacement) during open heart surgery were monitored in a continuous, on-line and real-time manner. On-line power spectral analysis was performed according to the five different stages of the operation. RESULTS: Power density tended to increase in the high frequency (HF) band during the ventilator-supported stages of the open heart procedures, i.e., the pre-cardiopulmonary bypass (CPB) and the off-CPB periods. The power density in other frequency bands during the whole course of general anesthesia otherwise decreased significantly, with the lowest values occurring during CPB. The power density in very low frequency (VLF) band was much higher than in other bands during CPB, and became the major component of total power density in this period. CONCLUSIONS: The balance between sympathetic and parasympathetic components of autonomic nervous system changes rapidly during open heart surgery and needs careful monitoring. By utilizing PSA of SAP, mathematical error might be an obstacle of using LF:HF ratio as an index of autonomic balance during the CPB period when the HF density approaches zero.

Aged↗