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P Alfonsi

Publications and source records attributed to P Alfonsi.

At least 19 recordsLinked to original sources
PubMed2003

Postanaesthetic shivering. Epidemiology, pathophysiology and approaches to prevention and management.

Postanaesthetic shivering is one of the leading causes of discomfort for patients recovering from general anesthesia. During EMG records, the distinguishing factor from shivering in fully awake patients is the existence of clonus similar to that recorded in patients with spinal cord transection. They coexist with the classic waxing and waning signals associated with cutaneous vasoconstriction (thermoregulatory shivering). The causes responsible for their appearance primarily include hypothermia, which sets in due to thermoregulation inhibition by anesthetics. However, we also note the existence of shivering associated with cutaneous vasodilatation (non-thermoregulatory shivering) one of the origins of which is postoperative pain. Apart from the discomfort and aggravated pain, postanaesthetic shivering raises metabolic demand proportionally to the solicited muscle mass and the patient's cardiac capacities. No link has been demonstrated between their occurrence and an increase in cardiac morbidity but it is preferable to avoid postanaesthetic shivering since it is oxygen draining. Prevention mainly entails preventing hypothermia by actively rewarming the patient. Postoperative skin surface rewarming is a way of obtaining the threshold shivering temperature while raising the skin temperature and improving the patient's comfort. However, it is less efficient than certain drugs such as meperidine, nefopam or tramadol, which act by reducing the shivering threshold temperature.

Anesthesia↗
PubMed2001

Postanaesthetic shivering: epidemiology, pathophysiology, and approaches to prevention and management.

Along with nausea and vomiting, postanaesthetic shivering is one of the leading causes of discomfort for patients recovering from general anaesthesia. The distinguishing factor during electromyogram recordings between patients with postanaesthetic shivering and shivering in fully awake patients is the existence of clonus similar to that recorded in patients with spinal cord transection. Clonus coexists with the classic waxing and waning signals associated with cutaneous vasoconstriction (thermoregulatory shivering). The primary cause of postanaesthetic shivering is peroperative hypothermia, which sets in because of anaesthetic-induced inhibition of thermoregulation. However, shivering associated with cutaneous vasodilatation (non-thermoregulatory shivering) also occurs, one of the origins of which is postoperative pain. Apart from causing discomfort and aggravation of pain, postanaesthetic shivering increases metabolic demand proportionally to the solicited muscle mass and the cardiac capacity of the patient. No link has been demonstrated between the occurrence of shivering and an increase in cardiac morbidity, but it is preferable to avoid postanaesthetic shivering because it is oxygen draining. Prevention mainly entails preventing peroperative hypothermia by actively rewarming the patient. Postoperative skin surface rewarming is a rapid way of obtaining the threshold shivering temperature while raising the skin temperature and improving the comfort of the patient. However, it is less efficient than certain drugs such as meperidine, clonidine or tramadol, which act by reducing the shivering threshold temperature.

Adrenergic alpha-Agonists↗
PubMed2000

Acute opioid tolerance: intraoperative remifentanil increases postoperative pain and morphine requirement.

BACKGROUND: Rapid development of acute opioid tolerance is well established in animals and is more likely to occur with large doses of short-acting drugs. The authors therefore tested the hypothesis that intraoperative remifentanil administration results in acute opioid tolerance that is manifested by increased postoperative pain and opioid requirement. METHODS: Fifty adult patients undergoing major abdominal surgery were randomly assigned to two anesthetic regimens: (1) desflurane was kept constant at 0.5 minimum alveolar concentrations and a remifentanil infusion was titrated to autonomic responses (remifentanil group); or (2) remifentanil at 0.1 microg. kg-1. min-1 and desflurane titrated to autonomic responses (desflurane group). All patients were given a bolus of 0.15 mg/kg morphine 40 min before the end of surgery. Morphine was initially titrated to need by postanesthesia care nurses blinded to group assignment. Subsequently, patients-who were also blinded to group assignment-controlled their own morphine administration. Pain scores and morphine consumption were recorded for 24 postoperative h. RESULTS: The mean remifentanil infusion rate was 0.3 +/- 0.2 microg. kg-1. min-1 in the remifentanil group, which was significantly greater than in the desflurane group. Intraoperative hemodynamic responses were similar in each group. Postoperative pain scores were significantly greater in the remifentanil group. These patients required morphine significantly earlier than those in the desflurane group and needed nearly twice as much morphine in the first 24 postoperative h: 59 mg (25-75% interquartile range, 43-71) versus 32 mg (25-75% interquartile range, 19-59; P < 0.01). CONCLUSIONS: Relatively large-dose intraoperative remifentanil increased postoperative pain and morphine consumption. These data suggest that remifentanil causes acute opioid tolerance and hyperalgesia.

Analgesia, Patient-Controlled↗
PubMed1998

The effects of meperidine and sufentanil on the shivering threshold in postoperative patients. pascal.alfonsi@apr.ap-hop-paris.fr.

UNLABELLED: BACKGROUND. Meperidine (pethidine) reportedly treats postoperative shivering better than equianalgesic doses of other mu-receptor agonists. The authors' first goal was to develop a method to accurately determine postoperative shivering thresholds, and then to determine the extent to which meperidine and sufentanil inhibit postoperative shivering. METHODS: A computer-controlled infusion was started before operation in 30 patients, with target plasma concentrations of 0.15, 0.30, or 0.60 microg/ml meperidine or 0.1, 0.15, or 0.2 ng/ ml sufentanil targeted; patients were randomly assigned to each drug and concentration. The infusion was continued throughout surgery and recovery. Anesthesia was maintained with nitrous oxide and isoflurane. Core temperatures were approximately 34 degrees C by the end of surgery. The compensated core temperature at which visible shivering and a 20% decrease in steady-state oxygen consumption was recorded identified the shivering threshold. A blood sample for opioid concentration was obtained from each patient at this time. The ability of each opioid to reduce the shivering threshold was evaluated using linear regression. RESULTS: End-tidal isoflurane concentrations were <0.2% in each group at the time of extubation, and shivering occurred approximately 1 h later. Meperidine linearly decreased the shivering threshold: threshold (degrees C) = -2.8 x [meperidine (microg/ml)] + 36.2; r2 = 0.64, P = 0.0005. Sufentanil also linearly decreased the shivering threshold: threshold (degrees C) = -7.8 x [sufentanil (ng/ ml)] + 36.9; r2 = 0.46, P = 0.02. CONCLUSIONS: At a given dose, sufentanil inhibited shivering 2,800 times better than meperidine. However, the equianalgesic ratio of these drugs is approximately 4,900. That is, meperidine inhibited shivering better than would be expected based on the equianalgesic potency ratio. These data are thus consistent with clinical observations suggesting that meperidine indeed possesses special antishivering activity.

Adult↗
PubMed1995

The effects of pethidine, fentanyl and lignocaine on postanaesthetic shivering.

Pethidine is reported to be more effective than equi-analgesic doses of other opioids as an inhibitor of postanaesthetic shivering. The aim of this study was to verify whether this action resulted from a local anaesthetic effect of pethidine or from inadequate fentanyl dosage in previous studies. We studied 52 ASA 1 or 2 patients. They were randomly allocated, in a double-blind fashion, to one of four groups to receive either pethidine (0.85 mg.kg-1) or fentanyl (1.7 micrograms.kg-1) or lignocaine (1 mg.kg-1) or 0.9% saline. All the patients were shivering and had a core temperature below 36 degrees C during recovery from non-septic abdominal or orthopaedic surgery. After 15 min, all the patients given saline were still shivering, as were 92% in the lignocaine group. In contrast, only 23% of the patients who were given fentanyl still shivered (p < 0.01 versus saline) and 8% in the pethidine group (p < 0.001 versus saline). The mean (SD) core temperature in the pethidine group was slightly lower than that in the fentanyl group (35.1 (0.6) and 35.9 (0.5)) when the patients stopped shivering. Furthermore, shivering restarted in 6/10 patients in the fentanyl group after 15 min compared with 1/12 in the pethidine group. Our results show that fentanyl (1.7 micrograms.kg-1) can inhibit postanaesthetic shivering but this effect is less pronounced and of shorter duration than with pethidine (0.85 mg.kg-1).

Adult↗
PubMed1993

Equivalence of postoperative analgesia with patient-controlled intravenous or epidural alfentanil.

The analgesia and the frequency and severity of oxyhemoglobin desaturation related to alfentanil administration were compared in 32 patients randomly selected to receive patient-controlled analgesia (PCA) by either the epidural (EPI) or intravenous (i.v.) route for a mean period of 16 h after major abdominal surgery. Bolus increments of 250 micrograms of alfentanil with a lockout interval of 5 min for i.v. and of 10 min for EPI route were administered by a programmable pump. Oxygen saturation (SpO2) was monitored for 16 h, using a pulse oximeter; data were collected continuously and stored every 30 s via an interface connected to a computer. For the purpose of analysis, SpO2 was divided into six categories: 95%-100%, 90%-94%, 85%-89%, 80%-84%, 75%-79%, and 70%-74%. Both routes provided similar degrees of analgesia at rest and on coughing. Maximum pain relief was obtained earlier in the i.v. group (P < 0.01). The total consumption of alfentanil was 13,141 +/- 3471 micrograms (mean +/- SD) in the i.v. group and 8000 +/- 4213 micrograms in the EPI group (P < 0.001). The effects on SpO2 were not statistically different between the two groups. Cumulative time spent in each saturation category was similar for the EPI and i.v. groups. Severe desaturation episodes, defined as SpO2 < or = 85% for at least 60 s, occurred in 69% of patients in the EPI group and 56% in the i.v. group.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1991

[Spinal anesthesia with bupivacaine without glucose in the elderly: effect of concentration and volume on the hemodynamic profile].

This study aimed to compare the haemodynamic effects of two different glucose-free bupivacaine solutions is thirty patients aged more than 70 years (mean age 82 years) undergoing hip surgery under spinal anaesthesia. They were randomly assigned to two groups, group A to receive 2.5 ml of a 0.5% bupivacaine solution, and group B 10 ml of a 0.125% solution in normal saline. All the patients were therefore given the same dose of bupivacaine, 12.5 mg. Lorazepam (1 mg orally) was administered to all for premedication two hours beforehand. Those patients taking antihypertensive agents were given their last dose on the eve of surgery. Lactated Ringer's solution (500 ml) was infused to all before the spinal puncture. Systolic (Pasys), mean and diastolic arterial pressures, and heart rate, were recorded every minute before volume loading, and for 30 minutes after the start of the spinal anaesthesia. Ephedrine (3 mg every two minutes if required) was given whenever Pasys decreased by more than 30% of the pre-induction value. The upper level of sensory blockade was assessed by the pin-prick test, and the quality of motor blockade with the Bromage scale. The cephalad spread of the solutions was similar, as well as the haemodynamic profile in each group. The total dose of ephedrine required in each group was not significantly different. It may therefore be concluded that, in the elderly, the upper level of, and the haemodynamic changes due to, spinal anaesthesia do not depend on the concentration or the volume of glucose-free bupivacaine solution.

Age Factors↗
PubMed1989

[Use of halothane in a semi-closed circuit].

Halothane was administered to 10 ASA or 11 patients undergoing elective peripheral surgery. The vaporizer was included in the delivery gas line of the semiclosed system. Löwe's square root of time model of uptake was used to calculate the required doses of halothane. In order to reach an alveolar concentration corresponding to 1.3 MAC, 0.5 vol % of halothane (1.3 MAC) combined with 60 vol % of nitrous oxide (0.6 MAC) were administered at a fresh of 20 ml.kg-1. The ventilation controlled in order to maintain end-tidal CO2 partial pressure at a 5 vol %. Inspiratory halothane concentration was measured during the inspiratory plateau. The alveolar fraction was defined as being the mean end expiratory concentration. The latter was well above the theoretical values during the first 9 min of anaesthesia (0.85% at the 4 th min). This concentration then decreased progressively, becoming less than the expected value after 15 min (0.4% at the 30 th min). Löwe's model would therefore seem to lead to a gross overestimation of the amount of anaesthetic vapour to be delivered to a patient at the beginning of anaesthesia, and an underestimation thereafter.

Anesthesia, Inhalation↗
PubMed1985

Functional evaluation of velar insufficiency by means of the rhinomanometric method.

25 subjects aged between 5 and 17 years, 15 females and 10 males, underwent anterior rhinomanometry. 10 of them were normal and 15 affected by velar insufficiency following adenotonsillectomy in 11 case and palatosynthesis in 4. The rhinomanometric tracing was obtained while the patient repeatedly pronounced oral vowels such as a, e, i, c, u and CVs such as ka, ga. In normal subjects intranasal pressure modifications were represented by a series of dyphasic waves with a positive-negative polarity. In the subjects with velar insufficiency the waves were almost monophasic with positive polarity. During and after the phoniatric rehabilitation, waves returned to be dyphasic together with a progressive reduction of hypernasality. While morphology of the rhinomanometric tracing can be considered a reliable index of velar function, wave's amplitude is influenced by the anatomical conditions of the nasal cavity and by the intensity with which the subject pronounces the vowels and the CVs. Rhinomanometry represents therefore an atraumatic, rapid and reliable technique, easy to perform, in order to evaluate velopharyngeal function and to monitor the increase of velar function during and after treatment.

Adolescent↗