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Biomedical subjects

S C Choi

Publications and source records attributed to S C Choi.

At least 109 records · Page 6Linked to original sources
PubMed1981

Traumatic acute subdural hematoma: major mortality reduction in comatose patients treated within four hours.

To discover which factors contributed to recovery after surgical intracranial decompression, we reviewed the records of 82 consecutive comatose patients with traumatic acute subdural hematoma (ASDH) who were treated in a single center under a uniform protocol. The delay from injury to operation was the factor of greatest therapeutic importance. Patients who underwent surgery within the first four hours had a 30 per cent mortality rate, as compared with 90 percent in those who had surgery after four hours (P less than 0.0001). Other important prognostic variables included results of the initial neurologic examination, sex, multimodality-evoked potentials, and postoperative intracranial pressure (ICP). If all patients with traumatic ASDH were taken directly to hospitals equipped to diagnose and remove the hematoma within four hours of injury, mortality rates could be reduced considerably.

Accidents, Traffic↗
PubMed1981

Filtration pressure equilibrium: a statistical analysis.

Statistical analysis of data in published micropuncture studies was applied to determine: a) the number of rats and samples of glomerular capillary pressure (Pg), end-capillary oncotic pressure (COPE), and proximal tubule pressure (Pt), needed in a single study to state with 95% confidence that a measured mean net efferent effective filtration pressure (delta P*E) is within +/- mmHg of any true value, delta PE; b) the effect of intra-animal variation in Pg, COPE, and Pt values on the number of experiments needed; and c) the probability of obtaining a value for delta P*E that meets this criterion in multiple trials. Assuming no intra-animal variation in Pg, Pt, and COPE values and employing published interanimal variances, at least 42 rats should be studied in any series to show that -1 mmHg less than or equal to (delta P*E -- delta PE) less than or equal to 1 mmHg within 95% confidence limits. If intra-animal variances are 60% of the interanimal variances, 67 rats are needed to obtain that degree of confidence when a single measurement of Pt, Pg, and COPE is made in each rat, and 47 animals are required with five measurements per rat. A value for delta P*E within 2-3 mmHg of its true value is, however, attainable with confidence using a far smaller number of animals per series.

Animals↗
PubMed1981

Further experience in the management of severe head injury.

A prospective and consecutive series of 225 patients with severe head injuries who were managed in a uniform way was analyzed to relate outcome to several clinical variables. Good recovery or moderate disability were achieved by 56% of the patients, 10% remained severely disabled or vegetative, and 34% died. Factors important in predicting a poor outcome included the presence of intracranial hematoma, increasing age, abnormal motor responses, impaired or absent eye movements or pupil light reflexes, early hypotension, hypoxemia or hypercarbia, and elevation of intracranial pressure over 20 mm Hg despite artificial ventilation. Most of these predictive factors were assessed on admission, but a subset of 158 patients was identified in whom coma was present on admission and was known to have persisted at least until the following day. Although the mortality in this subset (40%) was higher than in the total series, it was lower than in several comparable reported series of patients with severe head injury. Predictive correlations were equally strong in the entire series and in the subset of 158 patients with coma. A plea is made for inclusion in the definition of "severe head injury" of all patients who do not obey commands or utter recognizable words on admission to the hospital after early resuscitation.

Adolescent↗
PubMed1981

Improved confidence of outcome prediction in severe head injury. A comparative analysis of the clinical examination, multimodality evoked potentials, CT scanning, and intracranial pressure.

An analysis of clinical signs, singly or in combination, multimodality evoked potentials (MEP's), computerized tomography scans, and intracranial pressure (ICP) data was undertaken prospectively in 133 severely head-injured patients to ascertain the accuracy, reliability, and relative value of these indicants individually, or in various combinations, in predicting one of two categories of outcome. Erroneous predictions, either falsely optimistic (FO) or falsely pessimistic (FP), were analyzed to gain pathophysiological insights into the disease process. Falsely optimistic predictions occurred because of unpredictable complications, whereas FP predictions were due to intrinsic weakness of the indicants as prognosticators. A combination of clinical data, including age, Glasgow Coma Scale (GCS) score, pupillary response, presence of surgical mass lesions, extraocular motility, and motor posturing predicted outcome with 82% accuracy, 43% with over 90% confidence. Nine percent of predictions were FO and 9% FP. The GCS score alone was accurate in 80% of predictions, but at a lower level of confidence (25% at the over-90% level), with 7% FO and 13% FP. Computerized tomography and ICP data in isolation proved to be poor prognostic indicants. When combined individually with clinical data, however, they increased the number of predictions made with over 90% confidence to 52% and 55%, respectively. Data from MEP's represented the most accurate single prognostic indicant, with 91% correct predictions, 25% at the over-90% confidence level. There were no FP errors associated with this indicant. Supplementation of the clinical examination with MEP data yielded optimal prognostic power, an 89% accuracy rate, with 64% over the 90% confidence level and only 4% FP errors. The clinical examination remains the strongest basis for prognosticating outcome in severe head injury, but additional studies enhance the reliability of such predictions.

Adult↗
PubMed1981

Reversible brain-stem dysfunction following acute traumatic subdural hematoma: a clinical and electrophysiological study.

Of 366 consecutive patients with severe head injury, treated and managed by a uniform protocol, 61 (17%) were admitted with signs of severe brain-stem dysfunction. Forty-three of the 61 patients (70%) had surgical mass lesions and 30% had diffuse brain damage. Twelve of the 61 patients (20%) survived, but only six patients made a good to moderately disabled recovery. All six of these patients had a traumatic acute subdural hematoma (SDH). The records of the 20 comatose patients with an acute SDH and severe brain-stem dysfunction were reviewed to discover which factors contributed to functional recovery. The average survivor was operated on within 2 1/2 hours after injury and the nonsurvivors within 4 1/2 hours. Prompt surgical intervention and prudent control of postoperative intracranial pressure were major factors in preventing permanent brain-stem damage, with a significance of p less than 0.05 and p less than 0.02, respectively. Measurement of multimodality evoked potentials in the early postoperative period correctly distinguished between reversible and irreversible brain-stem dysfunction in six of the seven patients.

Adult↗
PubMed1980

Statistical methods for determining prognosis in severe head injury.

Determining the prognostic significance of clinical factors for patients with severe head injury can lead to an improved understanding of the pathophysiology of head injury and to improvement in therapy. A technique known as the sequential Bayes method has been used previously for the purpose of prognosis. The application of this method assumes that prognostic factors are statistically independent. It is now known that they are not. Violation of the assumption of independence may produce errors in determining prognosis. As an alternative technique for predicting the outcome of patients with severe head injury, a logistic regression model is proposed. A preliminary evaluation of the method using data from 115 patients with head injury shows the feasibility of using early data to predict outcome accurately and of being able to rank input variables in order of their prognostc significance.

Blood Pressure↗
PubMed1975

The effect of surgery and pretreatment or posttreatment adjuvant chemotherapy on primary tumor growth in an animal model.

The Ca755 solid tumor in the C57B1 mouse has been used as a model to study the interrelationship of surgery and adjuvant chemotherapy on primary tumor growth. Surgery was performed on various days after tumor implantation. Surgical mortality increased with delay in surgery. The mean survival time (MST) was significantly increased by surgery. An increased cure rate in mice with late surgery may be due to immunological factors. Pretreatment cytoxan chemotherapy prior to a number of surgical days on the most effect schedule increased MST in the later surgical days primarily due to shrinkage of tumor and a diminished surgical mortality. Posttreatment chemotherapy significantly increased MST primarily on the basis of reducing tumor cell population after surgery and increasing both the cure rate and the time until death of those mice dying of regrowth of tumor. Optimal chemotherapy alone significantly increased MST compared to untreated controls. Optimal postsurgery chemotherapy increased survival longer than the additive increase of chemotherapy alone and surgery alone. This paper illustrates relationships between day of surgery dose and schedule of chemotherapy and effect on various measurable parameters. The results can best be understood in relationship to each other. It is suggested that adjuvant chemotherapy has specific definable benefits. It is apparent from human studies that carefully devised designs which consider these interrelationships are necessary if optimal therapeutic results are to be achieved.

Adenocarcinoma↗