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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
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1996

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↗
PubMed1996

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↗
PubMed1995

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↗
PubMed1994

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↗
PubMed1992

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↗
PubMed1992

Modest doses of nitroglycerin do not interfere with beef lung heparin anticoagulation in patients taking nitrates.

The results of a prior clinical report suggested that nitroglycerin may interfere with the anticoagulant effect of heparin. Therefore, 30 adult patients undergoing cardiac surgery were studied in a controlled, prospective fashion. Thirteen patients on chronic nitrate therapy received an intraoperative nitroglycerin infusion at 1 micrograms/kg/min intravenously. Seventeen patients received no preoperative or intraoperative nitrates (control group). Heparin, 300 units/kg, was administered to all patients in three consecutive doses: 40 units/kg, 80 units/kg, and 180 units/kg. The activated coagulation time and activated partial thromboplastin time were measured prior to heparin, and 5 minutes after each heparin dose. There were no differences in automated activated coagulation times or in activated partial thromboplastin times between the groups at any measurement period. The study is limited in that only patients on chronic nitrates were included in the treatment group and that only a modest dose of nitroglycerin was used. However, it is concluded that a modest dose of intravenous nitroglycerin does not interfere with the anticoagulant effect of boluses of beef lung heparin in patients undergoing cardiac surgery.

Adult↗
PubMed1991

Desmopressin acetate is a mild vasodilator that does not reduce blood loss in uncomplicated cardiac surgical procedures.

Desmopressin acetate (DA) is a synthetic analog of vasopressin that may improve perioperative coagulation in cardiac surgical patients. Twenty-seven adult patients with good left ventricular function and normal preoperative coagulation profiles scheduled to undergo elective cardiac surgery participated in the double-blinded, placebo-controlled study. The 14 patients in the DA group received the drug over 10 minutes (starting 15 minutes after protamine administration). The 13 patients in the placebo group received an equal volume of saline. Preoperative template bleeding time was longer in the placebo group (P = 0.04). Otherwise, there were no statistically significant differences between the groups in demographics, coagulation variables, renal concentrating function, blood loss, or transfusion requirements at any study interval. The only significant hemodynamic differences detected were an increase in cardiac output in the DA group and a corresponding decrease in systemic vascular resistance. Five of 13 patients who received DA required treatment for hypotension, whereas none of 12 patients who received placebo required treatment during the infusion (P = 0.008). The authors conclude that DA causes mild vasodilation, but does not reduce blood loss or transfusion requirements in patients undergoing primary uncomplicated cardiac surgical procedures.

Anesthesia, Intravenous↗
PubMed1990

Nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction in patients with mitral valvular disease.

Using the rapid-response thermistor pulmonary artery catheter and transoesophageal echocardiography, this study examined the effects of 100 per cent oxygen, 70 per cent nitrous oxide/30 per cent oxygen, and 70 per cent nitrogen/30 per cent oxygen on the pulmonary circulation and ventricular function in ten patients with pulmonary hypertension. In comparison with baseline measurements, nitrous oxide administration resulted in small but statistically significant (P less than 0.05) changes in mean arterial pressure (76 +/- 14 to 67 +/- 12), mean pulmonary arterial pressure (37 +/- 14 to 33 +/- 13 mmHg), and cardiac output (3.7 +/- 1.4 to 3.2 +/- 1.1 L.min-1). Seventy per cent nitrogen resulted in no significant changes from baseline. The repeat 100 per cent oxygen measurements were nearly identical to the nitrous oxide measurements. It is concluded that nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction during high-dose fentanyl anaesthesia in patients with mitral valvular disease.

Adult↗
PubMed1990

Importance of atrial systole to ventricular filling predicted by transesophageal echocardiography.

This study documented mitral flow velocity patterns in anesthetized patients with ischemic heart disease and left ventricular dysfunction and investigated the relationship between transmitral flow velocity measurements and the hemodynamic response to ventricular pacing. Twenty-four patients in sinus rhythm without evidence of mitral valve disease undergoing elective myocardial revascularization were studied. Anesthesia consisted of a high-dose opioid-muscle relaxant-oxygen technique. After endotracheal intubation a 3.5-MHz phased-array transesophageal echocardiographic probe was inserted and positioned to obtain a long-axis view of the left atrium and left ventricle. The Doppler sample volume was placed at the mitral annulus with minimal cursor angulation, and the biphasic velocity tracing of transmitral blood flow was recorded. A hemodynamic profile was obtained, and cardiac output was measured in triplicate by thermodilution. Ventricular pacing was then instituted and the hemodynamic and thermodilution measurements were repeated. The peak early filling (E) velocity was 0.34 +/- 0.11 m/s, and the peak atrial (A) velocity was 0.38 +/- 0.09 m/s. The mean E:A ratio was 0.91 +/- 0.3, and the median value was 0.88. In sinus rhythm the cardiac index of those patients with an E:A greater than 0.88 (group 1) was 1.97 +/- 0.32 l/min and those with an E:A less than 0.88 (group 2) was 1.76 +/- 0.50 (NS). During ventricular pacing the patients in group 1 (1.56 +/- 0.32 l/min) had significantly higher cardiac indices than those in group 2 (1.21 +/- 0.31 l/min) (P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗