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Biomedical subjects

J P Gardaz

Publications and source records attributed to J P Gardaz.

At least 19 recordsLinked to original sources
PubMed2002

Combining transcutaneous blood gas measurement and pulse oximetry.

We are describing the preliminary results of tests performed in adult volunteers and in adult patients during and after general anesthesia with a miniaturized single sensor combining the continuous and non-invasive measurement of oxygen saturaiton by pulse oximetry (SpO2) and transcutaneous PCO2 (OxiCarbo sensor). The sensor is heated to 42 degrees C to arterialize the cutaneous tissue and is applied at the ear lobe with a special low-pressure clip. The results indicate a good agreement between ear lobe PCO2 and arterial PCO2 in the range 35 to 70 mmHg (10 patients, number of measurements 104, regression line TcPCO2 = 1.01 PaCO2 + 0.59 mmHg, bias 1.22 mmHg, SD 3.69 mmHg) and between ear lobe SpO2 and SaO2 (bias 0.44% with SD 0.77% in the range 80% to 100%, bias 1.39% with SD 1.43% in the range 60% to 80%). The ear lobe OxiCarbog sensor detects the SpO2 change 5 to 37 sec faster than a finger sensor and the PCO2 change 9 to 48 sec faster than a transcutaneous sensor fixed at the upper arm. Further improvements versus single sensors are a higher stability of the SpO2 signal and the possibility of performing long term SpO2 and PCO2 measurement at the ear lobe.

Adult↗
PubMed2001

[Twelve years of liver transplantation in Lausanne].

From 1988 to June 2000 138 transplantations were performed in 129 adult patients. Actuarial patient and graft survivals have been 80.7% and 75.4% at one year and 67.8% and 63.5% at 10 years. This compares favourably with the statistics of the European Liver Transplant Registry that collected data from more than 30,000 grafts. Over the twelve years of activity, the indications have become more liberal and the techniques have been simplified. The waiting list has therefore grown and some patients are now unfortunately dying before a graft can be found because the number of brain dead donors remains stable. In order to palliate this shortage, older donors are now being accepted even with co-morbidities and/or moderate alterations of the liver function tests. The use of live donors and the split of the best cadaveric grafts for two recipients will also reduce the gap between the demand and the offer.

Actuarial Analysis↗
PubMed2000

Blood profile during and after hemoglobin substitute administration.

The in vivo effects of Diaspirin Crosslinked Hemoglobin (DCLHb, Baxter Healthcare Corp.) on hematology and biochemistry are unknown. This study includes 6 calves (71.2+/-1.3 kg). In each animal a total of 2 litres of blood was exchanged for the same amount of hydroxylethyl starch (Haes, Fresenius) (n=3) or DCLHb (n=3), which is equivalent to 28cc/kg of blood substitute, over a period of 5 hours. The animals were allowed to survive 7 days. Blood samples were taken hourly during the perfusion protocol, at postoperative day (POD) 1, 2 and 7. ANOVA test was used for repeated measurements. Blood cell profiles were similar in both groups. Peak methemoglobinemia was 4.2% in the DCLHb group. Osmolarity was significantly higher in the DCLHb group with the greatest difference at POD 1 and 2. Postmortem analysis of the major organs did not show any sign of hemoglobin deposit in the DCLHb group. In the given setup DCLHb can be administered in a large quantity with good hematological tolerance and without any deposits in major organs. A prolonged plasma expander effect was observed.

Analysis of Variance↗
PubMed1998

[Assessment of intubation time and conditions under the influence of rocuronium].

PURPOSE: To evaluate the tracheal intubating conditions when intubation time is determined by the onset time of the neuromuscular block either of the adductor pollicis (AP) or of the orbicularis oculi muscle (OO). METHODS: In this prospective, double blind, randomised study, 40 adults ASA I-II undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the reference muscle (AP or OO) used to determine the appropriate intubation time. Induction of anaesthesia was achieved with 5-7 mg.kg-1 thiopentone, 1.5-2.5 micrograms.kg-1 fentanyl and 0.9 mg.kg-1 rocuronium (3 x ED95) for muscular relaxation. Supramaximal train of four stimulation of the ulnar and facial nerve every 10 sec was used to monitor the neuromuscular block. After visual loss of AP or OO contraction, tracheal intubation and quality of intubation assessment were performed by two independent anaesthetists. Data are expressed as mean and standard error of the mean (X +/- SEM). RESULTS: Curarisation time of the OO was shorter (110 +/- 4.9 sec) than that of the AP (144 +/- 5.5 sec; P < 0.0001). Intubation conditions were excellent in 95% and good in 5% of the patients in the AP group whereas in the OO group only 65% of the patients had excellent and 20% good intubation conditions (P < 0.05). Coughing was observed in 15% of patients in the OO group during tracheal intubation. CONCLUSION: Monitoring neuro-muscular activity of the AP using TOF to determine the appropriate tracheal intubation time and conditions in patients paralysed with rocurorium is more clinically relevant than monitoring the OO muscle.

Adult↗
PubMed1997

[Efficacy of ketanserin on postanesthetic shivering].

OBJECTIVE: To evaluate the clinical and electromyographic (EMG) effects of ketanserin (K), a serotoninergic receptor antagonist (5-HT2), on postoperative shivering (POS). STUDY DESIGN: Prospective, randomised, double-blind study. PATIENTS: Fifty ASA class 1 and 2 patients with major clinical postoperative tremor were studied. METHODS: POS was assessed clinically (0 = nil, 1 = moderate, 2 = severe). Inclusion criterion was a POS of 2 at admission in the recovery room. The mean arterial blood pressure, rectal temperature, SpO2 were recorded at admission (T0) and subsequently at T5, T10, T15, T30 and T60 minutes. Either 10 mg of K (n = 25) or a corresponding volume of a placebo (P) (n = 25) were intravenously injected. The EMG activity of the deltoid and quadriceps muscles was recorded continuously. Blood lactic acid concentration was measured at the end of POS. Results are expressed as mean +/- SEM. Parametric values were analysed with unpaired Student's t-test, and nonparametric values with chi 2 analysis. P < 0.05 was accepted. RESULTS: Demographic data, duration of anaesthesia, postoperative temperature, oxygen saturation, blood pressure and blood lactate concentration were similar between groups. The POS duration in the K group was significantly shorter than in the P group: 8.8 +/- 1.5 min and 15.5 +/- 1.5 min respectively (P < 0.01). The number of patients in the K group experiencing POS at T5 and T10 was significantly lower, when compared with those who had received the P (P < 0.05). CONCLUSION: At a dose of 10 mg, K administered in patients with POS during recovery, reduced significantly the duration and intensity of the shivering without noticeable side effects. This study suggests that this 5-HT2 antagonist is an efficient therapeutic tool for POS in adults.

Adult↗
PubMed1996

[Intubation conditions: importance of the rate of repetition of the train-of-four].

OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium.

Humans↗
PubMed1995

Effect of epinephrine on oxygen consumption and delivery during progressive hemorrhage.

OBJECTIVE: To determine whether, during hemorrhagic shock, the effect of epinephrine on energy metabolism could be deleterious, by enhancing the oxygen requirement at a given level of oxygen delivery (DO2). DESIGN: Prospective, randomized, control trial. SETTING: Experimental laboratory. SUBJECTS: Two groups of seven mongrel dogs were studied. The epinephrine group received a continuous infusion of epinephrine (1 microgram/min/kg) while the control group received saline. INTERVENTION: Dogs were anesthetized with pentobarbital, and shock was produced by stepwise hemorrhage. MEASUREMENTS AND MAIN RESULTS: Oxygen consumption (VO2) was continuously measured by the gas exchange technique, while DO2 was independently calculated from cardiac output (measured by thermodilution) and blood oxygen content. A dual-lines regression fit was applied to the DO2 vs. VO2 plot. The intersection of the two regression lines defined the critical value of DO2. Values above critical DO2 belonged to phase 1, while phase 2 occurred below critical DO2. In the control group, VO2 was independent of DO2 during phase 1; VO2 was dependent on DO2 during phase 2. In the epinephrine group, the expected increase in VO2 (+19%) and DO2 (+50%) occurred under normovolemic conditions. During hemorrhage, VO2 immediately decreased, and the slope of phase 1 was significantly (p < .01) different from zero, and was significantly (p < .05) steeper than in the control group (0.025 +/- 0.005 vs. 0.005 +/- 0.010). However, the critical DO2 (8.7 +/- 1.7 vs. 9.7 +/- 2.4 mL/min/kg), the critical VO2 (5.6 +/- 0.5 vs. 5.5 +/- 0.9 mL/min/kg), and the slope of phase 2 (0.487 +/- 0.080 vs. 0.441 +/- 0.130) were not different from control values. CONCLUSIONS: The administration of pharmacologic doses of epinephrine significantly increased VO2 under normovolemic conditions due to the epinephrine-induced thermogenic effect. This effect progressively decreased during hemorrhage. The critical DO2 and the relationship between DO2 and VO2 in the supply-dependent phase of shock were unaffected by epinephrine infusion. These results suggest that during hemorrhagic shock, epinephrine administration did not exert a detrimental effect on the relationship between DO2 and VO2.

Animals↗
PubMed1995

Effect of clonidine on ICP and on the hemodynamic responses to nociceptive stimuli in patients with brain tumors.

The effect of clonidine on intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), heart rate (HR), and drug requirements was studied in 24 patients scheduled for elective cerebral tumor resection (ICP < or = 20 mm Hg). The patients were randomly assigned to one of two groups: Group P (placebo), 12 patients; Group C (clonidine 3 micrograms/kg 10 min before induction), 12 patients. In all patients, anesthesia was induced with a propofol infusion (500 micrograms/kg/min) combined with fentanyl 2 micrograms/kg, lidocaine 1.5 mg/kg, and vecuronium 0.1 mg/kg. Propofol was also used for maintenance. During the preinduction period, clonidine had no effect on ICP or HR, but in clonidine-treated patients, MAP and CPP decreased significantly in comparison to those of the placebo group. During induction, ICP and HR were stable and similar in both groups. MAP and CPP remained significantly lower in Group C. At intubation and Mayfield clamp application, ICP increased in both groups, with similar values at all times. MAP increased in both groups at intubation, Mayfield clamp application, and incision, staying lower, however, in Group C. CPP followed a pattern similar to that of MAP. Propofol requirements up to the 20th min were lower in Group C than in Group P (2.08 +/- 0.83 vs. 3.3 +/- 0.7 mg/kg, p < 0.05). Finally, throughout the study, eight patients in Group C versus two in Group P had a CPP value < 60 mm Hg for > or = 1 min (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Agonists↗
PubMed1989

A randomized comparison of total extracorporeal CO2 removal with conventional mechanical ventilation in experimental hyaline membrane disease.

Apnoeic oxygenation (AO) combined with extracorporeal CO2 removal (ECCO2R), using venovenous perfusion across a membrane area of 0.1 m2 has been shown to be feasible in six healthy anaesthetized rabbits. In a further twelve rabbits, ECCO2R has been randomly compared with conventional mechanical ventilation (CMV) following saline lavage to induce respiratory failure. Blood gases were maintained for up to 6 h within the same range (PaO2 = 8-20 kPa, PaCO2 = 4-6 kPa) in two groups of six by varying airway pressures and the oxygen fraction delivered either to the membrane lung (ECCO2R group) or to the ventilator (CMV group). The influence of single hourly sustained inflations (SI) on oxygenation was studied. ECCO2R subjects remained stable and survived. CMV subjects deteriorated and had 80% mortality. Hyaline membranes were absent from ECCO2R subjects and present in all CMV subjects. The response to SI suggests that a lung volume recruitment is maintained during AO for up to 1 h but is ineffective during CMV.

Animals↗