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Biomedical subjects

N Rosencher

Publications and source records attributed to N Rosencher.

27 records · Page 2Linked to original sources
PubMed1995

Shivering threshold during spinal anesthesia is reduced in elderly patients.

BACKGROUND: Both accidental and perioperative hypothermia are common in the elderly. The elderly are at risk because their responses to hypothermia may be delayed or less efficient than in those of younger subjects. For example, the vasoconstriction threshold during isoflurane anesthesia is approximately 1 degree C less in elderly than younger patients. However, the extent to which other cold defenses are impaired in the elderly remains unclear, especially in those older than 80 yr. Operations suitable for spinal anesthesia provided an opportunity to quantify shivering thresholds in patients of varying ages. Accordingly, the hypothesis that the shivering threshold is reduced as a function of age during spinal anesthesia was tested. METHODS: Twenty-eight ASA Physical Status 1-3 patients undergoing lower extremity orthopedic procedures were studied. Spinal anesthesia was induced without preanesthetic medication, using bupivacaine sufficient to produce a dermatomal level near T9. Electrocardiogram signals were recorded at 10-min intervals. Subsequently, an observer masked to patient age and core temperature identified the onset of sustained electromyographic artifact consistent with shivering. The tympanic membrane temperature triggering shivering identified the threshold. RESULTS: Three patients did not shiver at minimum core temperatures exceeding 36.2 degrees C. Fifteen patients aged < 80 yr (58 +/- 10 yr) shivered at 36.1 +/- 0.6 degrees C; in contrast, ten patients aged > or = 80 yr (89 +/- 7 yr) shivered at a significantly lower mean temperature, 35.2 +/- 0.7 degrees C (P = 0.002). The shivering thresholds in seven of the ten patients older than 80 yr was less than 35.5 degrees C, whereas the threshold equaled or exceeded this value in all younger patients (P = 0.0002). CONCLUSIONS: Age-dependent inhibition of autonomic thermoregulatory control in the elderly might be expected to result in hypothermia. That it usually does not suggests that behavioral regulation (e.g., increasing ambient temperature, dressing warmly) compensates for impaired autonomic control. Elderly patients undergoing spinal anesthesia, however, may be especially at risk of hypothermia because low core temperatures may not trigger protective autonomic responses. Furthermore, hypothermia in the elderly given regional anesthesia may not be perceived by the patient (who typically feels less cold after induction of the block), or by the anesthesiologist (who does not observe shivering). Consequently, temperature monitoring and management usually is indicated in these patients.

Adult↗
PubMed1994

[Comparison of Orth-Evac and Solcotrans Plus devices for the autotransfusion of blood drained after total knee joint arthroplasty].

Surgical wound blood which is ched through drains after total knee replacement surgery with a tourniquet may be returned to the patient using special collecting devices. This study aimed to compare two systems, Orth-Evac and Solcotrans Plus an to assess the safety of the reinfusion of non washed blood cells. It included 30 patients scheduled for total knee replacement surgery, free from tumoral or coagulation disease and allocated randomly in three groups of 10 each: the Orth-Evac group (OGr), the Solcotrans Plus group (SGr) and the Control group (CGr). The devices, not containing an anticoagulant, were connected to the deep suction drains in the operating room, after skin closure and before the tourniquet removal. The salvaged blood was reinfused in the subsequent six hours via a 40 microns filter. The volume of collected blood was measured and homologous blood was added as required, to maintain a hematocrit of 30%. A blood sample was obtained the day before surgery (D - 1), before reinfusion (D0), two hours later (D + 2h), one day later (D + 1), and from the collecting device before reinfusion. The statistical analysis used the Kruskal-Wallis test and Steel-Dwass procedure to confirm the difference between two groups. The three groups did not differ in age, weight, height and gender. The volume of salvaged and autotransfused blood was 925 +/- 156 mL in OGr and 605 +/- 178 mL in SGr respectively, transfusion of homologous blood was required in two patients of OGr, four of SGr and six of CGr. At D + 1, the hematocrit was comparable in all groups (OGr = 28%, SGr = 28.2% and CGr = 28.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Nifedipine and intraoperative core body temperature in humans.

BACKGROUND: Initial anesthetic-induced hypothermia results largely from core-to-peripheral redistribution of heat. Nifedipine administration may minimize hypothermia by inducing vasodilation well before induction of anesthesia. Although vasodilation would redistribute heat to peripheral tissues, thermoregulatory responses would maintain core temperature. After equilibration, the patient would be left vasodilated, with a small core-to-peripheral temperature gradient. Minimal redistribution hypothermia may accompany subsequent induction of anesthesia, because heat flow requires a temperature gradient. In contrast, similar vasodilation concurrent with anesthetic-induced vasodilation may augment redistribution hypothermia. Accordingly, the authors tested the hypothesis that nifedipine treatment for 12 h before surgery would minimize intraoperative redistribution hypothermia, whereas nifedipine treatment immediately before induction of anesthesia would aggravate hypothermia. METHODS: Patients undergoing hip arthroplasty were randomly assigned to: (1) 20 mg long-acting nifedipine orally 12 h before surgery, and 10 mg sublingually 1.5 h before surgery (n = 10); (2) nifedipine 10 mg sublingually just before induction of anesthesia (n = 10); and (3) no nifedipine (control, n = 10). Anesthesia was maintained with isoflurane and 60% nitrous oxide. Administered intravenous fluids were heated, but the patients were not otherwise actively warmed. RESULTS: Core temperature decreased 0.8 degree C in the first hour of surgery in the patients given nifedipine the night before and the morning of surgery, which was significantly less than in the control group (1.7 degree C in the first hour). In contrast, core temperature decreased 2.0 degrees C in the first hour of surgery in the patients given nifedipine immediately before induction of anesthesia. During the subsequent 70-130 min of anesthesia, core temperature decreased at roughly comparable rates in each group. After 130 min of anesthesia, core temperature in the two nifedipine-treated groups differed by 1.6 degrees C, and the temperatures in all three groups differed significantly. CONCLUSIONS: Vasodilation induced by nifedipine well before induction of anesthesia minimized redistribution hypothermia, presumably by decreasing the core-to-peripheral tissue temperature gradient. In contrast, redistribution hypothermia was aggravated by administration of the same drug immediately before induction of anesthesia. Drug-induced modulation of vascular tone thus produces clinically important alterations in intraoperative core temperature.

Administration, Oral↗
PubMed1992

[Effects of nifedipine premedication on peroperative hypothermia].

The intraoperative time-course of core temperature in patients premedicated with nifedipine (n = 30) was compared to that of control patients (n = 30). Distal oesophageal temperature (TCORE) was recorded every five minutes during total hip replacement in 60 adults ranked ASA 1 to 2. Patients in the control group were only premedicated with 100 mg of oral hydroxyzine. The treatment group consisted of 30 patients taking nifedipine for blood pressure control or coronary insufficiency. They were given 10 mg sublingual nifedipine as well as the hydroxyzine premedication. Anaesthesia was induced with thiopentone, fentanyl and vecuronium, and maintained with nitrous oxide in oxygen and halothane in a semi-closed circuit. The slopes of the time-course for TCORE were established for each patient, using two linear regressions, between 0 and 0.5 h and from 1 to 2 h. The two groups did not differ in age, weight, ambient temperature, blood pressure, heart rate, and volume of unwarmed blood transfused. TCORE differed significantly from the 25th minute on until the end of the study period. Contrary to all expectation the TCORE at 2 h was higher in the nifedipine group (34.85 +/- 0.09 degrees C) than in the control group (34.01 +/- 0.14 degrees C, p < 0.001). TCORE decreased more rapidly in the control group during the first study interval (0 to 0.5 h), -1.50 +/- 0.60 degrees C.h-1 vs -2.34 +/- 1.02 degrees C.h-1 (p < 0.001). The second slopes did not differ particularly (-0.96 +/- 1.32 degrees C.h-1 vs -0.90 +/- 0.42 degrees C.h-1 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Comparison of effects of Elohes and albumin on hemostasis in orthopedic surgery].

A prospective study was carried out to determine the effects of Elohes, a low molecular weight hydroxyethylstarch, on haemostasis. Sixteen patients due to undergo total hip replacement were randomly assigned to one of two groups: group A, who were to receive up to 21 of 4% albumin to replace blood loss, and group E, 1.51 of Elohes. Patients were then given concentrated red cell packs (RCP) and lactated Ringer's solution so as to have a haematocrit value of 30%, up to the fifth postoperative day. The amount of blood lost intraoperatively was calculated by weighing the swabs and measuring the volume aspirated. Haemostasis was investigated on the eve of surgery, 3 hours afterwards, and then every second day (days 1, 3 and 5). Total blood loss and the number of RCP transfused were similar in both groups: 1,517 +/- 425 ml and 3.5 RCP, and 1,428 +/- 250 ml and 3.25 RCP in groups A and E respectively. Blood albumin concentrations fell in group E as expected, the starch diluting blood proteins. Bleeding time (Simplate), activated partial thromboplastin time, prothrombin time changed in the same way in both groups throughout the study period after infusion of either Elohes or albumin. The concentrations in factors II, V, VII and X fell by 30% three hours after surgery. Values returned to normal between days 1 and 3, the concentrations of some factors rising to values greater than preoperative values because of the postoperative inflammatory process (fibrinogen, factor VIII von Willebrand). However, there were no significant differences between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1985

[Blood loss and nausea during legal abortion].

The efficiency of oxytocic drugs in therapeutic abortion was studied in 113 women who were randomly assigned to either a control group (n = 44) receiving no oxytocic drugs, a group (n = 36) receiving 0.2 mg ergometrine by slow intravenous injection, or a group (n = 33) given 5 units oxytocin in a intravenous infusion throughout the procedure. The three groups were comparable with regard to the age of patients, the age of pregnancies and parity. The surgical procedure was the same in all three groups and carried out by the same surgeon. General anaesthesia was obtained with an infusion of 500 mg methohexitone and 500 micrograms fentanyl in 500 ml isotonic dextrose solution at a rate of 3 ml X min-1. The anaesthetic requirements were 2.94 +/- 0.80 micrograms X kg-1 fentanyl and 2.94 +/- 0,80 mg X kg-1 methohexitone. The criteria studied were the blood loss as measured by the volume aspired, the presence or absence of nausea and vomiting after the procedure, the age of pregnancy and the total amount of anaesthetic drugs given. No correlation was found between the amount of anaesthetic drugs given and the frequency of nausea and vomiting, and between the amount of blood lost (r = 0.287; ddl = 111; alpha = 17.322). The study did not, therefore, confirm the reputation of oxytocic drugs in reducing the bleeding. It seemed that, in therapeutic abortion, spontaneous uterine contraction was sufficient to control the bleeding. But a significant correlation was found between the amount of blood lost and the age of the pregnancy (r = 0.399; ddl = 111; alpha less than 1%).

Abortion, Legal↗