Biomedical subjects

S O Koh

Publications and source records attributed to S O Koh.

10 recordsLinked to original sources

PubMed2000

Effects of general and locoregional anesthesia on reproductive outcome for in vitro fertilization: a meta-analysis.

The objective of this meta-analysis was to evaluate prospective trials of general or locoregional anesthesia on reproductive outcomes (cleavage and pregnancy rate) for in vitro fertilization (IVF). Of 115 published studies retrieved from a search of articles indexed on MEDLINE from 1966 to February 1999, four studies with distinct general and locoregional anesthesia were deemed eligible for meta- analysis. The pooled relative risk and odds ratios were calculated. A test for homogeneity was also performed. The pooled log odds ratio was 1.03 (95% CI 0.90-1.18) in cleavage rate and 0.71 (95% CI 0.47-1.08) in pregnancy rate. Heterogeneity was negative. Cleavage and pregnancy rates were not significantly different in both the general anesthesia and locoregional anesthesia groups. Both anesthetic techniques were favorable to IVF procedure by available published evidence when anesthesia was needed.

Anesthesia, Conduction↗

PubMed1995

Incidence and predictors of postextubation laryngeal edema in pediatric patients with congenital heart disease.

Laryngeal edema developed in 10.1% of studied patients with congenital heart disease after cardiac surgery. The 181 patients were divided into two groups; those with laryngeal edema (group 1) and those without laryngeal edema (group 2). The mean ages in group 1 and 2 were 10 and 22.9 months. Group 1 patients were younger on average than those of group 2 (p < 0.05). The differences in the cardiopulmonary bypass time and anesthesia time between the two groups were not statistically significant. The duration of intubations and ventilatory support before and after the onset of laryngeal edema and the period of the ICU stay were longer in group 1 than in group 2 (P < 0.05). A predictor of postextubation laryngeal edema was not found in our patients from above mentioned parameters. We conclude that the higher incidence of laryngeal edema may be due to young age (most were under 1 year of age), and duration of intubation and ventilatory support.

Adolescent↗

PubMed1995

Effects of dexamethasone on laryngeal edema following short-term intubation.

Following short-term intubation for general anesthesia, respiratory difficulty may result from laryngeal or subglottic edema after extubation. We have hypothesized that this problem could be pretreated by administering a high-dose of dexamethasone intravenously before extubation. After glottic injuries were made under direct laryngoscopic view, intubation was performed and maintained for 1 hour in 33 rabbits. The rabbits were divided into 3 groups; dexamethasone (1 mg/kg) was administered to group 1(n=12) immediately after intubation and group 2(n=10) just before extubation; group 3(n=11) received normal saline, just before extubation. After extubation, subglottic excursion pressure was measured for 4 hours. 15 injured rabbit larynges and 3 normal ones were extracted for histologic section. 2 of 12 rabbits in group 1; 3 of 10 in group 2; and 5 of 11 in group 3, showed mild stridor after extubation(p>0.05). All rabbits developed maximum increase in subglottic pressure within 2 hours after extubation. Group 1 and 2 showed less increase in pressure compared to group 3(P<0.05), but here was no statistical difference between group 1 and 2(P>0.05). Histologic sections of the larynges showed less submucosal edema, including other changes in group 1 and 2, than in group 3(P<0.05). In conclusion, administering a high-dose of dexamethasone before extubation, is effective in prophylaxis and treatment of laryngeal injuries following short-term intubation in rabbits. This is especially true in edema.

Animals↗

PubMed1994

Complications during ventilatory support in patients with acute respiratory failure.

When ventilatory support becomes necessary in patients with acute respiratory failure, there is an associated increase in complications. We reviewed the charts of acute respiratory failure patients with the ventilatory support retrospectively who were admitted to the General Intensive Care Unit, Yonsei University College of Medicine, Seoul, Korea for the 6 months period, from March through August, 1990. The data included incidence of complications, morbidity and mortality, and reasons for and the duration of the ventilatory support. Of 269 patients receiving the ventilatory support, 107 patients (39.8%) developed 159 complications including alveolar hyperventilation (56 times), premature extubation (20 times) and right bronchial intubation (16 times). A single complication was associated with mortality rate of 19.5%, while with two or more complications, mortality rate was 60%, giving an average mortality rate of 29% when the complications were identified. The highest incidence of complications was in patients with multiple organ failure (80%). The highest mortality rate (50%) occurred in patients with heart failure. Patients with the ventilatory support less than one day had 23% incidence of complications and 2.7% mortality, while those with support for more than one month, these figures were 90.0% and 40.0% respectively (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1991

Epidural morphine on ventilatory function in chest trauma and thoracotomy patients.

Epidural morphine injection was done in nineteen patients who had been admitted from March to August 1990 to the Intensive Care Unit, Severance Hospital, Yonsei Medical Center for respiratory care including ventilator care. Morphine suplphate, 2.67 +/- 0.27 mg was injected one to three times to four patients after chest trauma, and to fifteen patients after thoracotomy. Tidal volume and vital capacity were increased from 4.45 +/- 0.48 and 8.31 +/- 0.50 to 6.91 +/- 0.41 and 12.81 +/- 0.73 mg/kg. However, respiratory rates decreased from 26.07 +/- 1.41 to 20.07 +/- 1.16/min. Inspiratory force increased from -13.40 +/- 1.31 to -26.53 +/- 1.82 cmH2O. Pain score decreased from 9.22 +/- 0.57 to 3.56 +/- 0.83 during this period. PaCO2 did not differ significantly (39.33 +/- 1.13 and 39.48 +/- 1.42 mmHg). Side effects such as pruritus and urinary retention were treated with naloxone 7 approximately 10 ng/kg/min. Mean arterial pressure and pulse rates stayed stable during the study periods. Ventilator hours and ICU stays differed from the control group. However, the duration was not statistically significant. The control group consisted of patients who were admitted during the six months from September 1989 to February 1990 to the ICU for respiratory care, without epidural morphine injection.

Adult↗

PubMed1990

Effect of anemia on pulse oximeter accuracy at low saturation.

A retrospective evaluation of simultaneous tests of oximeters of various manufacturers in volunteer subjects disclosed greater errors at low saturations in subjects with low hemoglobin (Hb) concentrations. Forty-three pulse oximeters of 12 manufacturers studied over a period of 10 months showed that, at a mean arterial oxygen saturation (SaO2) level of 54.5%, as Hb concentration fell, average pulse oximeter (SpO2) bias increased approximately linearly from 0 at Hb greater than 14 g/dl to about -14% at 8 less than Hb less than 9 g/dl. At SaO2 = 53.6%, the mean bias (SaO2--SpO2) of 13 oximeters of 5 manufacturers averaged -15.0% (n = 43) in a subject with Hb = 8 g/dl, but -6.4% (n = 390) in nonanemic subjects. The additional bias in the anemic subject increased with desaturation. It was 0.13% at SaO2 = 98.5% (n = 13), -1.31% at 87.5% (n = 38), -2.71% at 75.1% (n = 38), -5.18% at 61.3% (n = 26), and -9.95% at 53.6% (n = 41); n is the product of the number of oximeters and number of tests in each saturation range. The instruments that showed the greatest errors at low saturations in nonanemic subjects also showed the greatest additional errors associated with anemia (the range between manufacturers of anemic incremental error at about 53% being from -3.2 to -14.5%) and conformed well to the relationship bias (anemic) = 1.35 x bias (normal) -8.18% (r = 0.94; Sy.x = 3.3%). The error due to anemia was zero at 97% SaO2 and became evident when SaO2 fell below 75%.

Anemia↗

PubMed1990

Effect of halothane on hypoxic and hypercapnic ventilatory responses of goats.

We have measured the ventilatory responses to increased inspired carbon dioxide and to hypoxia in four goats awake and at 0.5%, 1.0% and 1.25% end-tidal halothane concentration. While maintaining PE'CO2 constant at each of three values (means 5.86, 6.45 and 7.2 kPa), PE'O2 was reduced rapidly from more than 25 kPa to 5.3-6 kPa for 3 min to record the increase in ventilation. Eleven sets of these 24 steady state points were obtained (2 PO2 x 3 PCO2 x 4 anaes. = 24). The mean isocapnic hypoxic ventilatory response (HVR) was 6.52 (SD 2.58) litre min-1 (n = 33) when awake, 5.62 (3.48) litre min-1 at 0.5% end-tidal halothane (ns), 3.05 (2.02) litre min-1 at 1% and 2.91 (2.12) litre min-1 at 1.25%, the last two being reduced significantly from awake and 0.5% halothane (P less than 0.05). With 1.25% halothane, HVR was reduced to 44.5 (18.6)% of the awake HVR. However, when HVR was expressed as % increase in ventilation produced by isocapnic hypoxia, it was 71 (19)% awake but 124 (65)% with 1.25% halothane, a significant increase with halothane (P less than 0.05). With 1.25% halothane, the carbon dioxide response slope decreased to 36.4 (26.4)% of control; hypoxia did not increase the slope significantly. Whereas previous studies in man have shown that halothane preferentially depresses hypoxic chemosensitivity and has a significant effect at 0.1 MAC, in the goat the hypoxic and carbon dioxide chemosensitivities were depressed equally. At 0.5% end-tidal concentration (about 0.5 MAC), halothane did not significantly depress hypoxic response.

Anesthesia, Inhalation↗

PubMed1990

Clinical experiences of fiberoptic bronchoscopy in patients with respiratory failure in the intensive care unit.

Seventy-nine fiberoptic bronchoscopies were performed in 46 Patients during 2 years in the Intensive Care Unit of Severance Hospital, Yonsei Medical Center. Bronchoscopies were done more than twice in 13 patients. Forty-three bronchoscopies were done through the orotracheal tube in 27 patients, and narcotics and sedatives such as morphine sulfate, diazepam and lorazepam were added with pancuronium bromide during 52 bronchoscopy procedures in 21 patients. Ventilatory support was accomplished by control mode ventilation for 63 bronchoscopies in 37 patients. Twenty-four patients were from the surgical department, and 37 bronchoscopies were performed in 18 patients in a post-thoracotomy state. Twenty-two patients were nonsurgical patients. We performed 48 bronchoscopies in 26 patients to treat lung haziness, 14 bronchoscopies in 3 patients to confirm the operative anastomosis after pneumonectomy or tracheoplasty, and 11 bronchoscopies to confirm the airway patency and vocal cord movement. We obtained good results from 41 bronchoscopies performed for therapeutic purposes and 28 bronchoscopies done for diagnostic purposes. But in 4 patients with pleural effusion and pneumonia, we could not get any improvement in chest X-ray taken after bronchoscopy. We suggested other procedures in 6 patients for diagnosis or treatment, such as suspension laryngoscopy, thoracentesis, ultrasonogram and laser surgery.

Airway Obstruction↗

PubMed1989

Errors in 14 pulse oximeters during profound hypoxia.

The accuracy of pulse oximeters from fourteen manufacturers was tested during profound brief hypoxic plateaus in 125 subject sets using 50 normal adult volunteers, of whom 29 were studied two to nine times. A data set usually consisted of 10 subjects, and 13 sets were collected between August 1987 and July 1988. In the first 6 sets, six 30-second hypoxic plateaus were obtained per subject at 55 +/- 6% oxyhemoglobin (O2Hb) (range, 40 to 70%). In the last 7 sets, three hypoxic plateaus were obtained at each of four levels, approximately 86, 74, 62, and 50% O2Hb, for the purpose of linear regression analysis. Inspired oxygen was adjusted manually breath by breath in response to arterial oxygen saturation computed on-line from end-tidal oxygen and carbon dioxide tensions. End-plateau arterial blood O2Hb was analyzed by a Radiometer OSM-3 oximeter, and plateau pulse oximeter saturation (SpO2) was read by cursor from a computer record of the analog output. Three to 13 instruments were tested simultaneously by using 1 to 3 duplicate instruments from each of one to seven manufacturers. Variations introduced by manufacturers were tested on subsequent sets in several instruments. An index of error, "ambiguity" (alpha) of oxygen saturation, was defined as the absolute sum of bias and precision (mean and SD of SpO2 - O2Hb) at O2Hb = 55.8 +/- 4.5%, preserving the sign when bias was significant at P less than 0.05. Ambiguity values for finger probes (unless specified) with latest data were: Physio-Control, 3.9 (ear, 3.3); Puritan-Bennett, -4.4; Criticare, 5.8 (forehead, 4.7); Kontron, 5.9 (infant probe) and 6.1 (ear, 5.8; forehead, 7.1); Biochem, -6.0; Datex 6.4 (ear, 6.9; forehead, 6.8); Critikon, 8.4; SiMed, 8.6; Marquest, 9.0; Novametrix, 10.2; Invivo, -12.2 (ear, -14.3); Nellcor, -15.1; Ohmeda, -21.2; and Radiometer, -21.2 (ear, -9.6). Linear regression slopes of 36 instruments from twelve manufacturers generally deviated from 1 in proportion to alpha. The data showed substantial differences in bias and precision between pulse oximeters at low saturations, the most common problems being underestimation of saturation and failing precision.

Adult↗

PubMed1989

Effects of hypoxia and hypocapnia on brain redox balance in ducks.

Low arterial CO2 tension (PaCO2) experienced by birds during high-altitude flight may result in cerebral vasoconstriction with reduced cerebral O2 delivery. To test this, brain redox balance and blood volume were studied during severe hypocapnia (PaCO2 11-20 mmHg) in ducks. Cerebrocortical redox balance, measured as relative [NADH], and blood volume were measured simultaneously with a fiber-optic fluorometer-reflectometer. Cerebrocortical blood volume (an index of blood flow) fell nearly linearly with PaCO2 during severe hypocapnia, even during severe hypoxemia. Cerebrocortical redox balance was shifted toward reduction of NADH ([NADH] increased) by both hypoxemia and hypocapnia. If hypocapnia causes similar changes in brain blood flow during high-altitude flight, tissue hypoxia will be exacerbated. Tolerance of brain tissue hypoxia during flight may be an important adaptation in high-flying birds.

Animals↗