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Biomedical subjects

T T Wei

Publications and source records attributed to T T Wei.

At least 19 recordsLinked to original sources

Dyspnea resulting from phrenic nerve paralysis after interscalene brachial plexus block in an obese male--a case report.

Phrenic nerve paralysis is a common complication in interscalene brachial plexus block. This complication is often ignored by most anesthesiologists because no clinical symptoms occur in patients who have no underlying lung disease. We present a case of an obese male suffering from dyspnea due to phrenic nerve block after interscalene brachial plexus block. The decreased respiratory reserve and direct compressing effect of the abdominal organs on the diaphragm in the supine position are thought to be the risk factors in this obese patient. Also discussed are the incidence, diagnostic methods, clinical presentation and treatments of phrenic nerve paralysis during interscalene brachial plexus block.

Adult

Effectiveness of a manually controlled infusion scheme of propofol and alfentanil mixture for endotracheal intubation in hypertensive patients: in comparison with thiamylal and nifedipine plus thiamylal.

BACKGROUND: Bolus administration of propofol for induction causes hypotension, especially in elderly hypertensive patient. Carefully titrated infusion of propofol minimizes adverse effects, such as hypotension, and permits a rapid recovery of its central effects. The objective of this study was to investigate the effect of a manually controlled infusion scheme of propofol and alfentanil mixture on hemodynamic stability during induction and endotracheal intubation for hypertensive patient. At the same time, the effectiveness of this scheme was compared with two other induction regimens (thiamylal or nifedipine plus thiamylal). METHODS: Sixty hypertensive patients undergoing orthopedic surgery were randomized into 3 groups (n = 20 per each group), None of the patients received premedication. Anesthesia was induced in group 1 (G1) with alfentanil 10 micrograms/kg. 30 s later, manual infusion of a mixture of propofol (10-12 mg/kg/h) and alfentanil (25 micrograms/kg/h) was performed for 2 min, followed by atracurium (5 mg) and propofol (1-1.5 mg/kg) as a bolus induction dose over 20 s, and then Suxamethonium (1.5 mg/kg) at 30-40 s later. Intubation was done while giving a continuous infusion of propofol and alfentanil. After intubation, the infusion rate was adjusted according to the blood pressure (BP) variation. Group 2 patients (G2) were induced with fentanyl (2 micrograms/kg), thiamylal (4-5 mg/kg), atracurium (5 mg) and succinylcholine (1.5 mg/kg). Induction of anesthesia in group 3 patients (G3) was the same as for G2, with additional sublingual nifedipine (1/2 capsule) 10 min prior to induction. Extra bolus dose of propofol (20 mg) or thiamylal (20 mg) was given at every 15 s if the systolic BP was still higher than 160 mmHg after induction by the above 3 regimens. The radial arterial pressure and electrocardiogram were continuously recorded for evaluation of hemodynamic changes. RESULTS: Post-intubation peak mean arterial pressure (MAP) in G1 and G3 were below to awake baseline values, while MAP of G2 was significantly higher than over awake baseline level (p < 0.001). The lowest MAP of G3 at post-intubation period before surgical stimulation were significantly lower than those of G1 and G2 (p < 0.001). Peak tachycardiac response to intubation in G2 was significantly higher than G1 (p < 0.05). After intubation, the peak rate pressure product were significantly higher in G2 compared with that in G1 (p < 0.05) and G3 (p < 0.001). CONCLUSIONS: The proposed manual infusion scheme of propofol and alfentanil mixture performed during induction and intubation attenuated the subsequent peak pressor response to incubation and reduced the hypotensive effect, in comparison to thiamylal or thiamylal plus nifedipine treatment, during post-intubation period. The same infusion scheme also attenuated the tachycardiac response to intubation.

Aged

[A proper size of endotracheal tube for infant and young child--a retrospective study in Mackay Memorial Hospital].

BACKGROUND: There are more than 2000 pediatric patients receiving surgery in Mackay Memorial Hospital each year. Most of these surgery were performed under general anesthesia with endotracheal tube; therefore choosing an appropriate size of endotracheal tube becomes an important issue in our daily practice. METHODS: Our principle is to choose an uncuffed Mallinckrodt endotracheal tube with a proper internal diameter (ID), ranging from 2.5 mm to 6.5 mm, which could be suitably and gently inserted into the trachea under full muscle relaxation. The tube would then be immediately removed and replaced with a smaller one if facing obvious resistance during intubation. After intubation, a leak test was applied to ascertain that there was no excessive gas leakage. We reviewed all anesthetic records of elective pediatric surgery in the recent 6 years, and the patients whose age above 8.5 years old and body weight (Wt) above 30 kg were excluded from this study. Using age (6476 cases) and Wt (6406 cases) as our parameters, we analyzed these data according to the distribution of each size of uncuffed endotracheal tube (UCETT) in different age and Wt intervals and compared them with the recommended Western reports. RESULTS: Our results revealed that (1) the UCETT size increases as age or Wt increases; (2) considerable spread of UCETT sizes for different age and Wt intervals and basically represent as normal distribution; (3) for the case of even age equal or above 2 years old (up to 8 years old), the ID of the most frequently used UCETT can be memorized as (18 + age in years) divided by 4 or the outer circumference (OC) of the Mallinckrodt UCETT (in French unit, Fr) = 19 + age in years; and (4) Wt as a parameter for tube size selection was as powerful as age (94.76% vs. 94.65%). CONCLUSIONS: From our results, we concluded that "whatever method of predicting tube size is used, tracheal tubes 0.5 mm larger and smaller should be available at the time of intubation so that the proper size can be chosen when the glottis is visualized."

Age Factors

Pulmonary edema induced by upper airway obstruction--report of 3 cases.

Pulmonary edema is a well-recognized complication of upper airway obstruction, and has been reported sporadically both in children and adults since 1977. Although the pathogenesis of pulmonary edema associated with upper airway obstruction is multifactorial, attention is primarily focused on excessive negative intrapleural and transpulmonary pressure produced by forceful inspiration against a closed glottis that results in transudation of fluid from the pulmonary capillary into the interstitial and alveolar spaces. We report 3 cases of pulmonary edema induced by upper airway obstruction after extubation following general anesthesia.

Adult

The use of intranasal nitroglycerin to prevent pressor responses during intubation in general anesthesia--a comparison of various doses.

BACKGROUND: Intranasal nitroglycerin (NTG) was first reported to successfully prevent an increase in arterial blood pressure following laryngoscopy and tracheal intubation by Hill et al. Various different effective dosages of NTG have been reported. Grover et al. indicated 0.75 mg of intranasal NTG to be the most suitable dose. However, no definite conclusion has yet been made. This study was designed to compare the efficacy of four different dosages of intranasal NTG (0.3, 0.5, 0.75, and 1.0 mg) in preventing pressor responses to laryngoscopy and tracheal intubation during the induction of general anesthesia. METHODS: One hundred patients (ASA I or II) scheduled for elective surgery were included. These study subjects were divided into five groups and randomly assigned to four different dosages of intranasal NTG and a placebo. Each group consisted of 20 patients. The NTG solution was administered 1 min before the injection of thiopental. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP) and heart rate (HR) were recorded before the induction of anesthesia (T1), before laryngoscopy (T2), and at 0, 3, and 5 min after tracheal intubation (T3, T4, and T5 respectively). RESULTS: In patients who received a placebo (control group), there were significant increases in SAP, MAP, HR and rate-pressure-product (RPP) associated with tracheal intubation. Tachycardia was noted in all experimental groups. The increases in MAP associated with tracheal intubation were significantly less in patients who received NTG of 0.5 mg or more but not 0.3 mg. Although 0.5 mg of NTG did attenuate the increases in SAP after tracheal intubation, the increases in SAP of the other three experimental groups were no less than that of the control group. Rate-pressure-product (RPP) values of the experimental groups were noted to be equal to or higher than those of the control group during the period of study. Contrary to the results of the study conducted by Grover et al., 0.75 mg of NTG did not attenuate the pressor responses. CONCLUSIONS: Intranasal NTG does not attenuate the pressor responses to laryngoscopy and tracheal intubation.

Administration, Intranasal

[4P- syndrome (Wolf-Hirschhorn syndrome) complicated with delay onset of malignant hyperthermia: a case report].

One 8-month-old female patient, weighted 5 kg, with congenital abnormality (4P- syndrome) underwent elective cheiloplasty for cleft lip and palate. Two hours later, with smooth anesthesia and operation, a life-threatening anesthetic complication of malignant hyperthermia occurred at pediatric intensive care unit. The immediate treatments were initially hyperventilating the patient with 100% O2 and cooling the patient with ice bags. Subsequently, intravenous dantrolene 2.5 mg/kg and symptomatic supportive care were administered successfully to treat the event. Upon reviewing the articles, we found that a congenital chromosome 4P deletion abnormality complicated with a delay onset of malignant hyperthermia has not been described previously.

Chromosome Aberrations

Comparative analgesic enhancement of alfentanil, fentanyl, and sufentanil to spinal tetracaine anesthesia for cesarean delivery.

Clinical investigations have shown that intrathecal local anesthetic combined with alfentanil, fentanyl, or sufentanil results in a synergetic interaction that improves perioperative analgesia. However, there are as yet few studies designed to compare equal potency dose of these three 4-anilinopiperidine analogues. This prospective study is an attempt to study the comparative analgesic properties of these three drugs. 156 parturients who had consented to spinal anesthesia for cesarean delivery, were anesthetized with 12 mg of tetracaine which was combined with various doses of these three opioids. The addition of these intrathecal opioids significantly improved analgesia. Intra-operatively, 26% of the control group had insufficient analgesia while all patients in the sufentanil or fentanyl groups had sufficient analgesia without needing any analgesic supplementation. Postoperatively 10 micrograms of sufentanil delayed the onset of any postoperative pain from 106 to 286 min. Side effects such as pruritus, respiratory depression, nausea, and vomiting were not different from those of the control group. This study indicates that 10ug sufentanil appears to be better than alfentanil or fentanyl in improving intra- and postoperative analgesia in parturient undergoing hyperbaric tetracaine spinal anesthesia for cesarean section.

Adolescent

[Anesthetic management of tetralogy of Fallot with absent pulmonary valve--a case report].

Tetralogy of Fallot is characterized by a VSD, overriding of the aorta, right ventricular hypertrophy, and pulmonary stenosis. Absence of the pulmonary valve occurs in 2.6-6% of patients with tetralogy of Fallot. Operative procedures to relieve respiratory symptoms have been described with an mortality of 35-100%. Respiratory compromise may be severe in these infants secondary to bronchial compression by the aneurysmally dilated pulmonary arteries and present a different hemodynamic profile than those with classic tetralogy of Fallot. An understanding of the anatomic and physiologic principles and their anesthetic implications will lead to improved management of these extremely ill infants. We reported the anesthetic considerations and management of a case of tetralogy of Fallot with absent pulmonary valve of an infant who experienced severe respiratory distress on the supine position.

Anesthesia

[Intrathecal meperidine attenuates shivering induced by spinal anesthesia].

Shivering is a common and complex phenomenon that occurs in many patients during spinal anesthesia. Shivering can increase oxygen consumption up to 500 per cent which may be detrimental to patients with decreased myocardial reserve. The metabolic costs and cardiorespiratory consequences of shivering are important particularly for patients with anemia, coronary arterial disease, cardiopulmonary insufficient, debilitated status or are elderly. We studied whether intrathecal meperidine could prevent shivering after spinal anesthesia. 60 patients with ASA class I-II were divided into intrathecal meperidine group (Group I) (n = 30) and control group (Group II) (n = 30). Group I received spinal tetracaine 12-16 mg with meperidine 0.2 mg/kg and Group II received spinal tetracaine 12-16 mg without meperidine. During operation the highest level of spinal anesthesia, ambient and rectal temperatures, blood pressure (BP) and heart rate (HR), presence or absence of shivering, intensity of shivering in both groups were recorded. Close observation for side effects was given post-operatively. There was a significant reduction (p < .005) in incidence of shivering in group I patients (16.7%) when compared with group II (56.7%). There was no or less side effects observed with other neuraxial opioids except nausea. We concluded that intrathecal meperidine could suppress shivering induced by spinal anesthesia.

Adult

[Nifedipine in preeclampsia for cesarean section].

The patients with preeclampsia undergoing emergent cesarean section is always a challenge to an anesthesiologist, because severe hypertensive response after laryngoscopy and tracheal intubation may result in life-threatening complication such as cerebral hemorrhage. Most of these patients receive magnesium sulfate for the prevention of convulsion. An ideal anti-hypertensive drug for preeclampsia should be effective, limited fall in blood pressure, rapid onset, maintaining uteroplacental blood flow, and less maternal and fetal side effects. We studied the efficacy of 10 mg sublingual nifedipine in attenuating the pressor response to intubation. We were also concerned about whether this calcium antagonist may inhibit uterine contraction and increase intra and postpartum hemorrhage when it is used with magnesium sulfate and general anesthesia. There were thirty-three patients in our study (16 in nifedipine group and 17 in control group). This study revealed that nifedipine attenuate the hypertensive response effectively. Uterine contraction response to oxytocic drugs was quite well in both groups. There was no significant difference in blood loss between nifedipine and control group. And no severe maternal and fetal adverse effect.

Adult

Is routine preanesthetic hemoglobin test necessary in minor pediatric surgery?

The value of preanesthetic assessment of anemia and analysis of the hemoglobin level prior to a minor pediatric surgery has been recently questioned in some reports. This study was to retrospectively analyse 8859 pediatric patients who underwent minor surgery in the period from January 1987 to December 1990 in our hospital. They were all ASA class I-II in physical status with age ranging from one month to 19 years. Those patients with their hemoglobin values determined at other laboratories or hospitals in spite of our recognition and those suspected of having an immune or oncologic disease were excluded from this study. The mean hemoglobin value of the patients under study was 12.99 +/- 0.82 g/dl. 0.62% of the patients (55) were found to have hemoglobin values less than 10 g/dl which were similar to the results obtained by Wood et al (0.7%) in 1981 and Roy et al (0.5%) in 1990. Among the 55 anemic patients, 41 (74.5%) were at the age between 2 to 4 months (within the physiologic anemic period of infancy). Sampling of blood for routine preanesthetic hemoglobin determination which caused discomfort and pain was often rejected by pediatric patients and struggle for escape also upset the children very much. Based on the results from our analysis, we suggest that in healthy pediatric patient scheduled for minor surgery routine hemoglobin test could be excluded. Hemoglobin test is selectively performed in a patient is anemic or under suspicious circumstances. The value and shortcomings of selective hemoglobin test before surgery require further evaluation.

Adolescent

[Intramuscular meperidine for the prevention of shivering in spinal anesthesia].

Intravenous meperidine 25mg has been employed effectively to treat shivering following regional anesthesia and general anesthesia. The study was designed to evaluate the effectiveness of intramuscular meperidine for the prevention of shivering in spinal anesthesia. The series consisted of 60 patients who were divided into 2 groups with 30 patients in each, undergoing lower abdominal or lower extremity surgery. All patients were given diazepam 0.1mg/kg i.v. for anxiolysis when they came to the operating room. In a double blind and randomized fashion, patients in the study (meperidine) group received meperidine 25mg IM (= 0.5ml). In the control group 0.9% N/S 0.5ml IM was given instead. All patients received spinal anesthesia 15 minutes later. Measurement of the levels of sensory loss to pinprick was made. The ambient temperature and the rectal temperature were continuously monitored to evaluate the effect of the change in body temperature on shivering during operation. The degree and the occurrence of shivering were carefully evaluated and recorded by a blind-trust observer. There was no significant difference in maximal analgesic level, ambient temperature and change of rectal temperature during operation between the groups. Shivering occurred in 17 patients (56.7%) in the saline group with an onset time of 7.9 +/- 2.5min following spinal anesthesia. In the meperidine group, shivering occurred only in 3 patients (10%) with an onset time of 54 +/- 29.5min after spinal anesthesia. There was a significantly lower incidence of shivering in the meperidine group than in the saline group (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen

[Clinical assessment of laryngeal mask airway in general anesthesia with spontaneous breathing].

The laryngeal mask airway (LMA) is a new form of oropharyngeal airway that provides an alternative to endotracheal intubation and face mask anesthesia in certain cases. Once the patient is adequately anesthetised, it can be inserted blindly without recourse to laryngoscopy. The advantages over standard mask anesthesia are: better airway control, minimal leakage of anesthetic gases, and it frees the anesthetist's hands, as no mandibular support is needed. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have risk of gastric regurgitation. Our preliminary study revealed that a clear and clinical satisfactory airway was obtained in 98.2% of patients. According to the intraoperative respiratory minute volume and arterial blood gases, the patency of the airway did not deteriorate during the course of the anesthesia. Blood pressure and heart rate were compared on induction in group I and II. Succinylcholine 1 mg/kg, thiopentone 4-6 mg/kg and fentanyl 2 micrograms/kg were used in group I while using the same dosage of succinylcholine and thiopentone without fentanyl for group II. We found no significant differences in vital signs between the two groups.

Anesthesia, General

[Changes in arterial pressure and heart rate during laryngeal mask insertion in hypertensive patients: comparison with endotracheal intubation].

The pressor response associated with laryngoscopy and endotracheal intubation may be harmful to patients with ischemic heart disease, hypertension or cerebrovascular disease. The Brain laryngeal mask airway can be inserted blindly and avoid the need for laryngoscopy. Our preliminary study compared the pressor response of tracheal intubation (T group) with that of laryngeal mask insertion (L group) in 19 and 33 hypertensive patients respectively. We also divided the patients of L group into sub-groups I (n = 16) and II (n = 17). All patients in T group and sub-group I were induced with fentanyl, thiopentone and succinylcholine while in subgroup II patients were induced with the same dosage of thiopentone and succinylcholine without fentanyl. The changes of blood pressure and heart rate exhibited a similar but attenuated pattern of response with laryngeal mask insertion in comparison with tracheal intubation. We also found no significant difference in pressor response between sub-group I and sub-group II in L group. In sum, laryngeal mask insertion may therefore offer some advantages over tracheal intubation in the anesthetic management of hypertensive patients in whom less pressor response is of particular concern.

Adult