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Biomedical subjects

D M Thys

Publications and source records attributed to D M Thys.

At least 19 recordsLinked to original sources

Povidone iodine and skin disinfection before initiation of epidural anesthesia.

BACKGROUND: Povidone iodine (PI) solution is used commonly for skin disinfection before epidural and spinal anesthesia. Although there have been reports indicating the presence of microbial contaminants in PI solution, none have evaluated the prevalence of PI contamination. The aims of this study were to assess the frequency of bacterial contamination of previously opened bottles of PI solution and to compare the effectiveness of new and previously opened bottles of PI solution for skin disinfection. METHODS: Twenty previously opened and ten previously unopened multiple-use bottles of PI solution were evaluated for microbial contamination. In addition, final swabs and PI solution used for skin disinfection in 80 patients undergoing elective epidural analgesia were evaluated. RESULTS: The inside of the bottle cap or the PI solution from 40% of the multiple-use PI bottles in use were contaminated. There was no growth from any previously unused PI bottles. Povidone iodine from newly opened bottles provided more effective skin decontamination than did solution from previously opened bottles. CONCLUSIONS: Multiple-use PI bottles in normal use may become contaminated by bacteria. In addition, PI solution from previously opened bottles was less effective than PI from previously unopened bottles. Based on these findings, if PI solution is chosen for skin antisepsis before initiation of epidural and spinal anesthesia, only single-use containers should be used.

Anesthesia, Epidural

A comparison of left ventricular performance indices measured by transesophageal echocardiography with automated border detection.

BACKGROUND: Automated border detection (ABD) allows semiautomated measurement of left ventricular (LV) areas. They can be combined with left ventricular pressure signals to generate pressure-area loops and pressure-dimension indices of contractility. This study compared conventional indices of ventricular performance (fractional area change [FAC] and circumferential fiber shortening [Vcfc]) with pressure-dimension indices of contractility. A secondary aim was to compare the effects of volatile anesthetics on the indices. METHODS: Using transesophageal echocardiography with automated border detection, FAC and Vcfc were obtained in 23 patients after cardiopulmonary bypass. Left ventricular pressures were obtained with a left ventricular catheter. Preload reduction by inferior vena caval occlusion was used to obtain end-systolic elastance (Ees), preload recruitable stroke force (PRSF), and dP/dtmax x EDA(-1) (EDA = end-diastolic area). In 11 patients, the measurements were repeated at 1 end-tidal minimum alveolar concentration of halothane or isoflurane. The results are expressed as mean +/- SD. RESULTS: After cardiopulmonary bypass, FAC was 31.1+/-7.9%, Vcfc was 0.6+/-0.2 circ x s(-1), Ees was 25.8+/-11.6 mmHg x cm(-2), PRSF was 60.8+/-26.6 mmHg, and dP/dtmax x EDA(-1) was 245+/-123.4 mmHg x s(-1) x cm(-2). At 1 minimum alveolar concentration of a volatile anesthetic agent, FAC, Vcfc, and dP/dtmax x EDA(-1) remained unchanged. Significant decreases in Ees (19%) and PRSF (28%) were observed. CONCLUSIONS: The association between pressure-dimension indices and Vcfc or FAC was weak or nonexistent. A reduction in myocardial contractility induced by the administration of volatile anesthetic agents was detected by Ees and PRSF, but not by FAC, Vcfc, or dP/dtmax x EDA(-1). After myocardial revascularization, Ees and PRSF appear more sensitive than FAC or Vcfc for measuring changes in contractility.

Anesthetics, Inhalation

Combined popliteal and posterior cutaneous nerve of the thigh blocks for short saphenous vein stripping in outpatients: an alternative to spinal anesthesia.

STUDY OBJECTIVE: To compare a combination of peripheral nerve blocks with spinal anesthesia in ambulatory patients undergoing short saphenous vein stripping. DESIGN: Prospective, randomized study. SETTING: University hospital. PATIENTS: 28 ASA physical status l and II ambulatory surgery patients undergoing short saphenous vein stripping. INTERVENTIONS: 14 patients received a popliteal block (sciatic nerve block at the popliteal fossa) using 30 ml of alkalinized 3% chloroprocaine and a posterior cutaneous nerve of the thigh block with 10 ml of 1% lidocaine. The 14 patients who were randomized to the spinal anesthesia group received 65 mg of 5% hyperbaric lidocaine. MEASUREMENTS AND MAIN RESULTS: There were no significant differences in age and gender between the two groups (mean age 53 +/- 13 years, 8 men and 20 women). Patients in the peripheral nerve block group recovered significantly faster in phase 1 of the postanesthesia care unit (PACU) (67 +/- 10 min vs. 122 +/- 50 min, p < 0.01) and were discharged home sooner (222 +/- 53 min vs. 294 +/- 69 min, p < 0.01) than the patients in the spinal anesthesia group. CONCLUSIONS: The combination of popliteal and posterior cutaneous nerve of the thigh blocks provided adequate anesthesia and a faster recovery profile with a similar subjective acceptance of both anesthetic techniques in ambulatory patients undergoing short saphenous vein stripping in the prone position.

Ambulatory Surgical Procedures

Cocaine screening of parturients without prenatal care: an evaluation of a rapid screening assay.

Illicit drugs are used widely by inner city patients in our society. Because cocaine ingestion can produce life-threatening arrhythmias and interact with anesthetic drugs, it is potentially useful for the anesthesiologist to know a high-risk patient's cocaine status before administering anesthesia. The commonly used methods to detect cocaine abuse, however, often require 1-3 days for laboratory processing. With these tests, anesthesiologists are unable to test for recent cocaine use in an emergency setting. A new rapid latex agglutination assay for urinary metabolites of cocaine (OnTrak Abuscreen; Roche Diagnostic Systems Inc., Branchburg, NJ) was compared with an assay used by many hospital laboratories. The prevalence of cocaine abuse in the group of unregistered parturients was found to be 68%, with the latex agglutination results exactly matching the hospital laboratory results (kappa = 1.0). A sensitive and specific method now exists that allows anesthesiologists to assess cocaine use rapidly, so that they can use this information when planning a patient's anesthetic.

Adult

Acupressure versus intravenous metoclopramide to prevent nausea and vomiting during spinal anesthesia for cesarean section.

Nausea and vomiting occur frequently during cesarean section under spinal anesthesia. Metoclopramide reduces intraoperative nausea and vomiting, but not without potential side effects. Acupressure, a noninvasive variation of acupuncture that involves constant pressure on the wrist, has been suggested as an alternative method to prevent nausea and vomiting. The aim of this study was to compare acupressure and intravenous (IV) metoclopramide for the prevention of nausea and vomiting during elective cesarean section under spinal anesthesia. Seventy-five patients were studied in a randomized, prospective, double-blind comparative trial. Group I patients received acupressure bands + 2 mLIV saline, Group II patients received placebo wrist bands + 10 mg IV metoclopramide, and Group III patients received placebo wrist bands + 2 mL IV saline. Patients who received either acupressure or metoclopramide prior to initiation of spinal anesthesia for cesarean section had much less nausea than patients in the placebo group. Acupressure is an effective, non-pharmacologic method to reduce intraoperative nausea during elective cesarean section in the awake patient.

Acupressure

A common epineural sheath for the nerves in the popliteal fossa and its possible implications for sciatic nerve block.

Sciatic nerve block in the popliteal fossa is associated with a highly variable success rate. Frequently, anesthesia is profound in the distribution of both the tibial (TN) and common peroneal nerves (CPN), although the response to nerve stimulation or paresthesia is obtained in the distribution of one division of the nerve. However, anesthesia in the distribution of only one division of the nerve is also a common occurrence under apparently identical clinical circumstances. Looking for a possible role of a common epineural sheath in these phenomena, we injected dye into the epineural sheath of the tibial nerve in 10 cadaver legs and observed its spread within the sheath. Injections of 15 mL and 30 mL of the dye resulted in a proximal spread of 147 +/- 34 mm and 172 +/- 50 mm, respectively, from the injection point 10 cm below the popliteal fossa crease. In a majority of the legs, the dye reached the division of the sciatic nerve in the popliteal fossa, bathing both the TN and CPN. Gross inspection and histologic examination of the sciatic nerve specimens revealed a common epineural sheath enveloping the TN and CPN. The presence of the common epineural sheath and its characteristics may have important clinical implications for sciatic nerve blockade in the popliteal fossa.

Humans

The association between Doppler transmitral flow variables measured by transesophageal echocardiography and pulmonary capillary wedge pressure.

The association between Doppler transmitral flow variables, measured by transesophageal echocardiography (TEE), and pulmonary capillary wedge pressure (PCWP) was studied in 88 patients undergoing coronary artery surgery. The Doppler flow variables and PCWP were measured after sternotomy by blinded investigators. In the first part of the study, patients were divided into two groups according to left ventricular (LV) ejection fraction (EF): Group A, EF > 35% (n = 38) and Group B, EF < or = 35% (n = 34). In Group B, significant correlations were found between deceleration time of early filling (DCT-E) and PCWP (r2 = 0.899) and deceleration slope of early filling and PCWP (r2 = 0.692), (P < 0.001 for both). When the relationship between DCT-E and PCWP was tested prospectively in a third group of patients [Group C; EF < or = 35% (n = 16)], a close agreement between the calculated and measured PCWP (bias = -0.55 +/- 3.87 mm Hg) was noted. The sensitivity, specificity, and positive predictive value of DCT-E > or = 150 ms for PCWP < 10 mm Hg were 93.3%, 100%, and 100%, respectively. In summary, patients with decreased left ventricular systolic function undergoing coronary artery surgery demonstrated high, statistically significant, correlations between PCWP and the deceleration time or deceleration slope of early diastolic filling as measured by transesophageal Doppler echocardiography.

Age Factors

Femoral and genitofemoral nerve blocks versus spinal anesthesia for outpatients undergoing long saphenous vein stripping surgery.

Long saphenous vein stripping (LSVS) surgery is often used to treat varicose veins. We tested the hypothesis that femoral nerve block (FNB) with genitofemoral nerve infiltration provides sufficient analgesia and superior recovery characteristics to spinal anesthesia for LSVS procedures in the ambulatory setting. Thirty-six patients were randomized to receive FNB with 30 mL of 3% alkalinized chloroprocaine, and 32 patients received spinal anesthesia with 65 mg of 5% hyperbaric lidocaine. Data collected included patient demographics, time required for induction of and recovery from anesthesia, postoperative anesthesia complications, and patient report of pain severity after the operation. During a follow-up call, a blinded observer noted the onset of any complications, the requirement for analgesics, and the patients' satisfaction with the anesthetic technique. Patients in the FNB group had significantly faster recovery (P < 0.01) and lower incidences of pain (P < 0.05) and complications (P < 0.05) than the patients in the spinal group. All patients who received FNB indicated that they would choose this type of anesthesia in the future, whereas five (15%) patients in the spinal group would refuse spinal anesthesia in the future (P < 0.01). We conclude that FNB is an excellent anesthetic choice for LSVS.

Adult

Anesthesia for the parturient with sickle cell disease.

A brief overview of the genetics, transmission, pathophysiology, and clinical manifestations of sickle cell disease is presented. Issues and management dilemmas specific to the parturient with sickle cell disease are discussed, along with recommendations regarding preoperative, operative, and postoperative care. Three case reports from our institution are used to illustrate problems that may occur in these patients.

Adult

Detection of intraoperative incidents by electronic scanning of computerized anesthesia records. Comparison with voluntary reporting.

BACKGROUND: The use of a computerized anesthesia information management system provides an opportunity to scan case records electronically for deviations from specific limits for physiologic variables. Anesthesia department policy may define such deviations as intraoperative incidents and may require anesthesiologists to report their occurrence. The actual incidence of such events is not known. Neither is the level of compliance with voluntary reporting. METHODS: Using automated anesthesia record-keeping with long-term storage, physiologic data were recorded every 15 s from 5,454 patients undergoing noncardiothoracic surgery. Recorded measurements of blood pressure, heart rate, arterial oxygen saturation, and temperature were electronically analyzed for deviations from defined limits. The computer system also was used by anesthesiologists to report voluntarily those deviations as intraoperative incidents. For each electronically detected incident: 1) the complete automated anesthesia record was examined by two senior anesthesiologists who, by consensus, eliminated case records with artifact or in which context suggested that the incident was not clinically relevant, and 2) the anesthesia information management system database was checked for voluntary reporting. RESULTS: In 473 automated anesthesia records, 494 incidents were found by electronic scanning of 5,454 automated anesthesia records. Sixty intraoperative incidents were eliminated, 25 due to artifact and 35 due to context. When the remaining 434 intraoperative incidents were checked for voluntary reporting, 18 (4.1%) matching voluntary reports were found. All intraoperative incidents that were reported voluntarily also were detected by electronic scanning. Based on a 10% sample, the sensitivity rate of electronic scanning was 97.2% (35/36), and the specificity rate was 98.4% (427/434). Among 413 cases with electronically detected intraoperative incidents, there were 29 deaths (7.0%), whereas there were only 79 deaths (1.6%) among 5,041 cases without incidents (chi 2 = 58.5, P < 0.001). CONCLUSIONS: The use of an anesthesia information management system facilitated analysis of intraoperative physiologic data and identified certain intraoperative incidents with high sensitivity and specificity. A low level of compliance with voluntary reporting of defined intraoperative incidents was found for all anesthesiologists studied. Finally, there was a strong association between intraoperative incidents and in-hospital mortality.

Anesthesiology

Anaesthetic management of caesarean section in a patient with active recurrent genital herpes and AIDS-related dementia.

We report the anaesthetic management of a pregnant patient with multiple manifestations of HIV infection who underwent Caesarean section. A 30-yr-old, HIV-positive, Haitian woman presented with acute psychosis at 28 weeks' gestation. A diagnosis of HIV dementia complex was made and haloperidol therapy was started. Five days after admission the patient was found to be in labour and tocolytic therapy with terbutaline was commenced. A vaginal lesion compatible with herpes simplex virus was observed which was treated with acyclovir. After 3 days of tocolytic therapy there were no further signs of preterm labour. Two weeks later, at 30 weeks' gestation, the patient's membranes ruptured spontaneously. The herpes labialis lesion was still present and urgent Caesarean section was begun using subarachnoid 0.75% bupivacaine 1.5 ml. The patient had no intraoperative problems and a 1700-g healthy male child was delivered.

AIDS Dementia Complex

Esmolol and intraoperative myocardial ischemia: a double-blind study.

Forty patients scheduled to undergo elective myocardial revascularization were included in a randomized, double-blind, placebo-controlled study to evaluate any influence of esmolol on the incidence of myocardial ischemia. Calibrated recordings of ECG leads II and V5 were continuously monitored with the QMED Monitor One TC (Qmed Inc, Clark, NJ) from the time of arrival in the operating room holding area through the induction of anesthesia, using a high-dose opioid technique, and until the initiation of cardiopulmonary bypass. One group received a bolus of esmolol, 1.0 mg/kg, followed by a continuous infusion of 100 micrograms/kg/min. The other group received a bolus and infusion of saline placebo of equal volume. The incidence of myocardial ischemia was not significantly different between the groups on arrival in the holding area, or at any study point. Heart rate, mean arterial pressure, and the number of patients developing myocardial ischemia during the course of the study also did not differ significantly between the groups. There were significant decreases in heart rate and mean arterial pressure compared with the awake baseline values in both groups during multiple study points. It is concluded that esmolol was ineffective at treating preexisting or new-onset myocardial ischemia at this dosage in this clinical setting.

Adrenergic beta-Antagonists

An evaluation of two activated clotting time monitors during cardiac surgery.

The activated clotting time (ACT) is a commonly used method for assessing the degree of anticoagulation during cardiac surgery. Two automated ACT monitors were evaluated in 29 adult patients undergoing cardiac surgery. The HemoTec ACT monitor (HTC; HemoTec, Inc., Englewood, CO) was evaluated using 0.8 ml of whole blood in dual-chamber, high range kaolin cartridges. The Hemochron ACT monitor (HCH; International Technidyne, Inc, Edison, NJ) was evaluated using 2.0 ml of whole blood in glass tubes with diatomaceous earth activator. Following sternotomy, a coagulation profile consisting of HTC, HCH, and a partial thromboplastin time (PTT) was obtained (T0). Beef lung heparin was administered in 3 consecutive doses: 40 units/kg (T1), 80 units/kg (T2), and 180 units/kg (T3). Coagulation profiles were drawn 5 minutes after each dose. Following cardiopulmonary bypass (CPB), coagulation profiles were drawn 15 minutes (T4), 2 hours (T5), and 24 hours (T6) after the protamine dose. HTC and HCH ACT values differed significantly at T1, T2, and T4 (p less than 0.001). In the pre-CPB period, the HCH ACT correlation with PTT divided by its control value (PTT/CTL) (r = 0.73) was significantly better (p = 0.02) than the correlation of HTC ACT with PTT/CTL (r = 0.41). In the post-CPB period, both HCH ACT (r = 0.45) and HTC ACT (r = 0.30) correlated weakly with PTT/CTL. In the bias analysis, the limits of agreement (of all HCH and HTC ACT values) showed that HTC ACT is between 61% and 133% of the HCH ACT value in 95% of determinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult