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Biomedical subjects

E J Quebbeman

Publications and source records attributed to E J Quebbeman.

67 records · Page 4Linked to original sources
PubMed1976

Influence of inflation and atelectasis on the hypoxic pressor response in isolated dog lung lobes.

Apnoeic left lower lobes of dog lungs were inflated by increasing alveolar pressure or decreasing pleural pressure, or the lobes were collapsed and exposed to decreasing pleural pressure with the bronchus occluded. Under each of these conditions the lobe could be made 'hypoxic' by perfusion with mixed venous blood or 'normoxic' by perfusion with systemic arterial blood. Inflation of the lobes diminished the hypoxic presor response. The relative influence of decreasing pleural pressure on inflated and collapsed lobes was such that at low pleural pressures resistance to flow through the hypoxic atelectatic lobe was no greater than that through the inflated normoxic lobe. The results indicated that the level of lung inflation can alter the effectiveness of the hypoxic pressor response in reducing perfusion to underventilated regions.

Air Pressure↗
PubMedDate not supplied

Pharmacokinetic evaluation of a new oral cyclosporine formulation.

STUDY OBJECTIVE: To compare the pharmacokinetics of a new oral cyclosporine preparation with those of cyclosporine solution diluted in Isocal and the intravenous formulation. DESIGN: Randomized, crossover trial. SETTING: Tertiary care referral center. PATIENTS: Seven pediatric liver transplant recipients who were receiving oral cyclosporine as part of their immunosuppressive regimen. All patients completed the study. INTERVENTIONS: Pharmacokinetic studies were performed with the intravenous and oral dosage forms. Patients received one dose of intravenous cyclosporine, and then were randomized to receive their usual oral cyclosporine dose incorporated into a chocolate wafer or mixed with Isocal. After a minimum of 3 days, the alternative preparation was administered. Serial cyclosporine blood samples were collected at predetermined intervals for 12 hours after the third dose for each regimen. Concentrations were determined by high-performance liquid chromatography. The data for the three dosage forms were fit simultaneously with a two-compartment model. MEASUREMENTS AND MAIN RESULTS: No difference was seen in F, ka, Cmax, and tmax between the two oral cyclosporine preparations (p > 0.05). No new rejection episodes occurred during the study period. CONCLUSIONS: We conclude there is no difference in the bioavailability of the oral solution and the chocolate formulation. We believe the new preparation may increase patient compliance and ensure administration of a complete dose compared with the currently marketed solution.

Administration, Oral↗
PubMedDate not supplied

Analysis of pain management in critically ill patients.

We analyzed the adequacy of pain control for 17 trauma patients during the initial part of their stay in the intensive care unit, and assessed reasons for inadequate analgesia, if it occurred. Patients, and physicians, and nurses were interviewed. A verbal pain intensity scale was used to determine whether patients received adequate analgesia. Patients were asked if the pain hindered their activities, and whether they requested pain medication from their caregivers. Caregivers were questioned whether patients received adequate analgesia. Prescribed morphine regimens and the amount of narcotic administered were analyzed. Twenty-seven percent of patients rated pain intensity as moderate and 47% as severe. Ninety-five percent of housestaff and 81% of nurses reported the patients received adequate pain control. Forty-seven percent of the patients who had moderate or severe pain asked their physician for more pain medication, and 65% asked the nurse. Thirteen residents did not order a larger dose of morphine due to concern about respiratory depression or hypotension. Morphine dosages ranged from 1-8 mg intravenously every 1-2 hours as necessary. Nurses administered less than the maximum amount ordered 58% of the time. The mean dosing interval was 2.3 hours. Barriers to adequate pain management were disparity in the perception of pain between patients and caregivers; patients not requesting more analgesia despite despite the presence of moderate to severe pain; and physician and nurse concerns about patients' adverse physiologic response to increased dosages.

Adult↗
PubMedDate not supplied

Ablation of liver metastasis: is preoperative imaging sufficiently accurate?

The recent introduction of cryotherapy and radiofrequency ablation of liver metastasis has expanded the indications for treatment. As technology has advanced, a percutaneous approach has been developed. Percutaneous treatment, however, requires accurate preoperative imaging. From 1993 to 1999, 179 patients underwent operative exploration for treatment of suspected hepatic metastases from colorectal carcinoma. One hundred seventy-seven patients were staged by preoperative CT, two patients were staged by MRI, and complete data were available in 176. Hepatic tumor count by preoperative imaging was compared to intraoperative tumor count obtained by inspection, palpation, ultrasonographic examination using a 3.5/7.5 MHz T probe, and careful gross sectioning of the resected specimen. Post hoc analysis was performed on 35 CT scans by two radiologists who specialize in abdominal CT. These radiologists were blinded to the intraoperative findings. Their interpretations were compared to the intraoperative counts and to each other. Thirty-four (19%) of 179 patients were deemed untreatable at operation because of unsuspected overwhelming liver involvement in 11 (6%) or extrahepatic metastases in 23 (13%). For the group, CT was accurate in 80 patients (45%), showed more lesions than were found in 16 (9%), and showed fewer metastases than were found in 80 (45%). When the preoperative scan predicted a solitary metastasis, it was correct in 45 (65%) of 69 patients and underestimated disease in 24 (35%). In the post hoc analysis, the mean numbers of lesions reported by the two radiologists did not differ from the mean number of tumors found; however, the radiologists' counts agreed on 16 (59%) and disagreed on 11 (41%) of the scans. The accuracy of CT decreased with increasing numbers of lesions. Regardless of the type of preoperative imaging, intraoperative findings altered the course of the operation in 96 (55%) of 176 patients. Preoperative imaging is not sufficiently accurate to permit adequate percutaneous treatment of hepatic metastases from colorectal carcinoma.

Bias↗
PubMedDate not supplied

The malfunctioning silastic catheter--radiologic assessment and treatment.

Occlusion of silastic catheters is attributed to several documented causes. One factor not yet adequately documented is fibrin sleeve formation. In this instance, the catheter functions for infusion purposes, but blood withdrawal is no longer feasible. This is a troublesome occurrence when encountered in the clinical setting. This report reviews the assessment of fibrin sleeve formation, the use of catheter phlebography and treatment with low-dose streptokinase. Seventeen instances of the inability to aspirate blood from silastic catheters are evaluated with restoration of full catheter function in all cases after streptokinase administration.

Aged↗
PubMedDate not supplied

Aminoglycoside serum concentration sampling via central venous catheters: a potential source of clinical error.

Two patients receiving aminoglycosides via central venous Silastic catheters were noted to have serum drug concentrations markedly divergent from expected results. Study of these patients, and of four additional patients prospectively selected for study, demonstrated that three of five patients had higher peak and/or trough aminoglycoside serum concentrations--when blood was obtained from the central venous catheter--than were contained in simultaneous samples from peripheral blood; these divergent results were noted after the catheter had been in use for more than 1 week; divergent results were not improved by additional catheter flushing prior to central venous blood sampling. These observations suggest that spurious aminoglycoside serum concentration results may sometimes be obtained when blood sampling is performed from central venous Silastic catheters, and can result in improper drug dosage alterations. It is necessary to access the timing, processing, and reliability of serum drug-monitoring practices on a routine basis to preclude such problems, and to reassess individual patient-monitoring studies which are inconsistent with anticipated results.

Adult↗
PubMedDate not supplied

Glucose response to abrupt initiation and discontinuation of total parenteral nutrition.

Plasma glucose was studied during the initiation of total parenteral nutrition (TPN) and the discontinuation of TPN without a tapering schedule. Blood was sampled every 5 minutes for 2 hours after the start of TPN and 1 week later as TPN was discontinued. A total of 14 initiations and 14 discontinuations were studied in 18 patients. Severity of illness in patients ranged from stable condition postoperatively to multiple-system failure; six patients had diabetes mellitus. The TPN solution was a 3:1 admixture that provided a caloric intake equal to 1.2 times the resting energy expenditure, with 40% fat and 60% carbohydrate calories. An average of 1963 kcal was provided per day (340 g of glucose, 79 g of fat). During the initiation phase, the mean increase in plasma glucose was 60 mg/dL. The increase for diabetic patients was 79 +/- 14 mg/dL compared with 52 +/- 23 mg/dL for the nondiabetics. During the discontinuation phase, the mean plasma glucose decreased 40 +/- 20 mg/dL; two patients with high concentrations of regular insulin (50 and 100 units) showed an increase in plasma glucose when the TPN was stopped. Plasma glucose returned to the preinfusion baseline after discontinuation. During both initiation and discontinuation, plasma glucose showed little change after the first 60 minutes. No clinical symptoms of hypoglycemia were observed. In conclusion, TPN as a 3:1 admixture can be safely started as full nutrition support and stopped abruptly without a tapering schedule. Plasma glucose response is rapid, predictable, and mostly complete within 60 minutes.

Adolescent↗
PubMedDate not supplied

Pinch-off syndrome: a rare etiology for central venous catheter occlusion.

BACKGROUND: Catheter pinch-off syndrome is a rare and often misdiagnosed complication of tunneled Silastic central venous catheters. Pinch-off syndrome occurs when the catheter is compressed between the first rib and the clavicle, causing an intermittent mechanical occlusion for both infusion and withdrawal. We report its incidence in a large series of catheter insertions and describe the clinical presentation, radiographic findings, and recommended treatment. METHODS: A total of 1457 tunneled Silastic central venous catheters that were inserted using the percutaneous subclavian approach were prospectively studied. Indications for catheter placement included bone marrow transplant, continuous or intermittent chemotherapy, long-term antibiotics, and parenteral nutrition. Catheters were evaluated for clinical presentation of an occlusion relieved by postural changes and radiographic findings of luminal narrowing. RESULTS: Pinch-off syndrome was identified in 16 (1.1%) catheters. Radiographic findings were present in all catheters; clinical findings were present in 15 catheters. Clinical symptoms presented within a median of 2 days after placement (range, 0 to 167 days). Partial or complete catheter transection, a serious sequela of catheter pinch-off syndrome, occurred in 19% of the identified catheters. CONCLUSIONS: (1) Catheter pinch-off syndrome presents clinically as a catheter occlusion related to postural changes; (2) clinical symptomatology should be confirmed radiographically; and (3) catheter removal with a more lateral replacement in the subclavian vein or in the internal jugular vein will avoid a recurrent complication.

Anti-Bacterial Agents↗
PubMedDate not supplied

Narcotic use in the hospital: reasonably safe?

OBJECTIVE: To determine the causes and frequency of overdoses associated with the administration of opioid analgesics in hospitalized patients. DESIGN: Case series. SETTING: Two acute care teaching hospitals. PATIENTS: Eighty-one hospitalized patients who received naloxone for a clinically suspected narcotic overdose. INTERVENTIONS: Three investigators reviewed each patient who received naloxone during a 12-month period. The patients were judged to have a narcotic overdose if caregivers documented an immediate improvement in mental status, respiratory rate, or blood pressure after naloxone administration. MAIN OUTCOME MEASURES: The number and causes of narcotic overdoses were determined. The frequency of morphine and meperidine overdoses was calculated. The number of incidents reported using incident or adverse drug reaction reports or the appropriate International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code. RESULTS: In the 22 overdoses that occurred, 14 (64 percent) were caused by medication prescribing, compounding, or administration errors and potentially were preventable. The remaining eight patients experienced an overdose despite receiving appropriate amounts of opioids. The frequency of overdoses was 0.4 and 0.2 percent of total patients receiving morphine or meperidine, respectively, at the two hospitals. Nonreporting of these narcotic overdoses was frequent. In one hospital, 1 incident report and 3 adverse drug reactions were reported for 17 overdoses. At the second hospital, 1 incident report and 1 adverse drug reaction were reported for 6 overdoses. None of the patient charts included an ICD-9-CM code that documented the problem. CONCLUSIONS: The causes of overdoses are not limited to prescribing and administration errors. Some patients, despite proper execution of appropriate orders, develop a narcotic overdose. Caregivers must be aware of this problem and monitor patients for a decrease in mental status and respiratory rate. In addition, we conclude that an important number of hospitalized patients develop an overdose even though the frequency is low related to the number of patients receiving narcotics.

Adverse Drug Reaction Reporting Systems↗
PubMedDate not supplied

Reconstruction of the incompetent abdominal stoma.

The occasional patient who has an incompetent stoma that does not respond to traditional methods of treatment by the general surgeon or the ET nurse might be aided by the use of a customized procedure designed by the plastic and reconstructive surgeon.

Aged↗
PubMedDate not supplied

Current patterns of prescribing and administering morphine in trauma patients.

We attempted to characterize the current prescribing practices and administration patterns for intravenous intermittent morphine in trauma patients in a multicenter, open prospective, observational study. The subjects were 141 patients admitted to the surgical intensive care units (ICU) of five United States trauma centers within 12 hours of injury who received intermittent intravenous morphine for pain relief. The study was conducted from April 15, 1992, to February 15, 1993. Data obtained during the first 32 hours of the ICU stay included morphine regimen, doses administered, and time between doses. One hundred sixty-one orders were prescribed by surgeons. The most frequently ordered dose was 2-4 mg and the most frequently ordered interval was every hour as necessary. There was no relationship between the severity of injury and the minimum dose ordered. During the 492 nursing shifts studied, 1257 doses were administered. Of these, 44% were at or below the minimum amount prescribed by the surgeons. Thirty-three percent of the patients received a dose at an interval of more than 3 hours. We concluded that small amounts of narcotic analgesics are given to severely injured patients, and amount ordered is not affected by the severity of injury.

Adolescent↗