Biomedical subjects

W M Ho

Publications and source records attributed to W M Ho.

36 records · Page 2Linked to original sources

PubMed1997

Monitoring of blood catecholamines by microdialysis and microbore LC with a dual amperometric detector.

The accuracy of in vivo microdialysis for monitoring blood catecholamines and their metabolites in Lan-Yu mini-pigs was evaluated. To prevent blood clots and irritation, a microdialysis probe was secured in a Y-shaped tube. The tube was connected to an arterio-venous shunt, in a mini-pig, for in vivo experiments. Perfusates were injected onto a microbore LC equipped with a dual electrochemical detector (the upstream electrode was set at an oxidizing potential and the downstream electrode was set at a reducing potential. The typical large offscale peak or interfering peaks on the anodic chromatograms were mostly eliminated on the cathodic chromatograms, thereby providing reliable measurements of early eluters. Early eluates, such as norepinephrine and epinephrine, with reversible redox behaviour could be detected at the downstream reducing electrode. A comparison of the present method and a conventional blood-drawing method showed good correlation (r = 0.775-0.983 for all analytes).

3,4-Dihydroxyphenylacetic Acid↗

PubMed1997

Unilateral pulmonary edema during general anesthesia--report of two cases.

Unilateral presentation of pulmonary edema, though well known to occur, is an uncommon entity. Previous reviews of this subject have discussed the different etiologies, which include rapid reexpansion of collapsed lung, down lung syndrome (gravitational edema), systemic-to-pulmonary arterial shunts, heart failure, compression or occlusion of pulmonary vasculatures, obstruction of a bronchus and an acute manifestation of neuropulmonary reaction (neurogenic pulmonary edema). Occurrence of this complication during surgery, however, is even rarer. We report 2 cases of unilateral pulmonary edema occurring during general anesthesia for elective surgery.

Adult↗

PubMed1997

Hypovolemic shock induced by laparoscopic cholecystectomy--a case report.

Since its introduction and development in the 1960s, laparoscopic cholecystectomy has become widely accepted by the medical community and the public as the treatment of choice for various gallbladder disorders. We present a 46-year-old male who underwent laparoscopic cholecystectomy, during which inadvertent penetration of the first trocar resulted in injury of the abdominal aorta and then hypovolemic shock ensured. The time from notification of shock by the anesthesiologist to switch of procedure to exploratory laparotomy for stanching hemorrhage was twenty minutes. During the intervention, blood loss was over 3,000 ml and despite rapid infusion of plasma expander, blood pressure could only be maintained between 40/18 to 60/20 mmHg. After the patient became stabilized and blood pressure was elevated to acceptable levels, conventional cholecystectomy was performed instead. Perioperative blood loss of 7,300 ml was estimated. In total, the patient received 24 units of packed red blood cells, 12 units of fresh frozen plasma, and 12 units of platelets. After the operation, the patient was transferred to the surgical ICU for further observation. For 24 h at the ICU, blood pressure remained unstable, urine output decreased gradually, and scrotal and leg edema developed. Forty-four h after admission to the surgical ICU, arrhythmia and profound hypotension were noted and cardiac arrest ensued. After resuscitation for 2 h, the patient could not be revived and succumbed to cardiovascular decompensation secondary to acute renal shutdown and continuous retroperitoneal hemorrhage.

Cholecystectomy, Laparoscopic↗

PubMed1995

Ipratropium bromide and intraoperative bronchospasm.

BACKGROUND: Ipratropium bromide (IB) is a synthetic anticholinergic bronchodilator which is effective when administered by inhalation. Therefore, IB may be effective for the management of intraoperative bronchospasm. This study was designed to evaluate the effects of inhaled IB in the management of intraoperative bronchospasm induced by endotracheal intubation. METHODS: Nine asthmatics who were asymptomatic preoperatively were investigated. They developed bronchospasm after endotracheal intubation. IB 120 micrograms was aerosolized through the endotracheal tube. Heart rate, peak inspiratory pressure (PIP), airway resistance (Raw) and pulmonary resistance (Rpul) before and after IB administration were recorded and calculated. RESULTS: IB 120 micrograms relieved wheezing in 11 +/- 4 min (mean +/- SD), and significantly decreased PIP in 5 min and reached peak effects at 120 minutes after administration. Raw and Rpul also decreased during similar time intervals. Heart rates had no significant change after IB administration. CONCLUSIONS: The present study indicated that IB 120 micrograms could abate the intraoperative bronchospasm caused by airway hyperreactivity induced by endotracheal intubation in preoperatively asymptomatic asthmatic patients, and may have a role in the management of intraoperative bronchospasm.

Aged↗

PubMed1994

Observation of coagulation change during induced hypotensive anesthesia and autologous plasma transfusion.

Coagulation change was studied in 16 adult female patients undergoing radical hysterectomy with BPLND surgery. None had preoperative alterations in coagulation or liver function and was receiving anticoagulant or antiplatelet medication. Sixteen ASA class I-II were divided into 2 groups randomly with eight patients in each group. One group accepted autologous plasma transfusion near the end of surgery, the other group did not. Autologous plasma was retrieved by plasma saver post induction of anesthesia. Every patient received induced hypotensive anesthesia during the operation. Whole blood coagulation status was quantitated by using thromboelastography (TEG). Blood samples for TEG were obtained before induction of anesthesia, after closure of peritoneum, and 2 hours post autologous plasma transfusion or 2 hours post peritoneum closure. Most parameters measured by TEG showed improved coagulation status in autologous plasma transfusion group. We concluded that coagulation change was minimal during induced hypotension, and improved coagulation was obtained 2 hours post autologous plasma transfusion during radical hysterectomy with BPLND surgery.

Adult↗

PubMed1994

Pulmonary edema and rapid transfusion: the comparison between rapid intravenous and intraarterial infusion in the severely hemorrhagic anesthesized pigs.

BACKGROUND: Patients with shock often develop pulmonary edema (PE) after rapid and massive fluid supplement and intravenous infusion. Rapid intraarterial infusion (RIA) is often used for fluid supplement in cardiac surgery, but has not yet been applied to treatment of hemorrhagic shock. However, by perfusing the ischemic peripheral organs through RIA, the fluid should flow first through the venous system to the heart and lung in less volume at lower speed. Therefore, the probability of developing PE should be less than that in rapid intravenous infusion (RIV) to the heart and lung in the same condition regarding volume and speed. Accordingly, we compared RIV and RIA in the treatment of hemorrhagic shock (HS) to determine if RIA provides any beneficial effect in reducing the development of PE. METHODS: Eleven male mini-pigs weighing 17.5-32 kg were randomly divided into two groups to have RIV and RIA. Under general anesthesia, HS was induced by shedding blood (about 35 ml/kg) through the femoral artery until the mean arterial blood pressure (MAP) fell to 50 mm Hg. This condition was maintained for three hours. Then, lactated Ringer's solution (LRS) was infused thrice by force through a femoral artery (RIA) or an external jugular vein (RIV) at a speed of 25 ml/kg/min for 3 min. Data include hemodynamics, arterial blood gases, urine output, total extravascular lung water index (ETVI), and total amount of infused LRS used to induce gross PE (endotracheal release of pinkish foamy sputum). Serum concentrations of catecholamines, platelet activating factor (PAF) and thromboxane B2 (TxB2) were measured. RESULTS: The total amount of LRS needed to induce gross PE was significantly greater in RIA than in RIV group. ETVI after rapid transfusion with a total of 225 ml/kg LRS was significantly less in RIA than in RIV group. Also, TxB2 concentrations in serum were less in RIA group. However, there was no difference in changes of hemodynamics, blood gases, acid-base, pulmonary shunting, urine output, serum concentrations of PAF or catecholamines between these two groups. CONCLUSIONS: RIA may be a better choice for fluid replacement in HS in terms of decreasing the development of PE and lessening the release of ETVI and TxB2 in severely hemorrhagic anesthetized pigs. Further human investigation is warranted.

Animals↗

PubMed1991

Abnormal thyroid hormone levels in critical nonthyroidal illness.

Low levels of thyroid hormone in the absence of clinical hypothyroidism often happen to patients with critical non-thyroidal illnesses (NTI). Low thyroid hormone concentrations in serum do not necessarily mean hypofunction of the thyroid gland; rather it is a helpful adaptation of the human body to the underlying diseases. We collected 133 hospitalized cases of critical NTI and analyzed the incidence of this phenomenon. Fifty-three per cent of the patients had T3 level lower than 60 ng/dl (normal:85-165 ng/dl) and 60% had T4 level lower than 6 ug/dl (normal:6-12 ug/dl). The lowest levels were observed in patients who had sepsis, were aged over 70 or died in this admission. Free T4 and TSH levels were within normal range in most cases. There is a strong negative correlation between the prognosis and the level of T4 in these patients. Those patients with markedly low levels of T3 and T4 should be treated more sophisticatedly.

Humans↗

PubMed1990

Cardiovascular effects of large doses of pentamorphone in the dog.

The cardiovascular effects of large doses of pentamorphone were evaluated in nine mongrel dogs basally anesthetized with sodium thiopental, 25 to 30 mg/kg, intravenously. All dogs were mechanically ventilated with 100% oxygen, and the PaCO2 was maintained between 35 and 40 mm Hg. Mean arterial pressure (MAP), central venous pressure, heart rate (HR), cardiac output (CO), pulmonary artery pressure, and pulmonary artery occluded pressure were measured, and stroke volume and systemic and pulmonary vascular resistances were calculated. Baseline measurements were obtained, then pentamorphone, 10 micrograms/mL, was given as an intravenous infusion at 2.5 micrograms/kg/min. Additional data were obtained after infusion of 25, 50, 75, 100, 125, 150, 200, 250, 300, and 350 micrograms/kg of pentamorphone. The inspired gases were then changed to 50% nitrous oxide in oxygen, and after a 20-minute equilibration period, an additional set of data was collected. Pentamorphone, 25 micrograms/kg, decreased HR 50%, MAP 65%, and CO 54%. No further changes in any measured or calculated variables were observed with additional doses of pentamorphone. The addition of 50% nitrous oxide to the inspired gas mixture had no effect on any measured or calculated hemodynamic variable. The minimal hemodynamic effects of pentamorphone in the dog suggest that further investigation into its use as an anesthetic is warranted.

Analysis of Variance↗

PubMed1989

Thyroid function during isoflurane anesthesia and valvular heart surgery.

Proper thyroid function is essential for maintaining cardiovascular integrity during normal and stressful situations. In this study, the effects of isoflurane-O2 anesthesia and surgical stress on serum TSH, T4, free T4, T3, rT3, and cortisol were investigated in nine patients before, during, and after valve surgery. Compared with preoperative control values, serum TSH decreased in the postoperative period. Both T4 and free T4 had similar decreases after cardiopulmonary bypass (CPB) and remained depressed postoperatively. Both T3 and rT3 decreased at the start of cardiopulmonary bypass; T3 remained low in the postoperative period, while rT3 increased. Cortisol decreased during anesthesia and surgery in the prebypass period, but increased during cardiopulmonary bypass and in the postoperative period. The results suggest that isoflurane-O2 anesthesia during valve surgery produces a rapid decrease in T3, resulting in the low T3 syndrome postoperatively. Isoflurane, in the dose studied, similar to fentanyl, can suppress the cortisol response to anesthesia and surgery in the prebypass period, but not during and after CPB.

Adult↗

PubMed1988