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J Sanchis

Publications and source records attributed to J Sanchis.

At least 19 recordsLinked to original sources
PubMed1995

Respiratory function deterioration is not time-linked with upper-limb onset in amyotrophic lateral sclerosis.

INTRODUCTION: In amyotrophic lateral sclerosis (ALS), symptoms apparently spread following regional rules, and depending on the site of onset. We examined if respiratory function deterioration appears earlier or is more severe in patients with upper-limb onset. MATERIAL & METHODS: We compared the results of various pulmonary function tests (PFT) obtained at diagnosis depending on the site of onset in 49 ALS patients. In a longitudinal study, we compared the deterioration of forced vital capacity (FVC) in relation to the site of onset, and analyzed the time elapsed to reach values below 80% of predicted according to site of onset, and we compared the survival depending on the site of onset. RESULTS: No significant differences in PFT were found in the upper-limb onset group in any of the analysis performed. No differences in survival were detected in any disease onset group. CONCLUSION: Pulmonary function deterioration does not appear to be time-linked to arm onset in ALS.

Adult↗
PubMed1992

Hemolytic-uremic syndrome associated with pancreatitis in an HIV-positive patient.

Hemolytic-uremic syndrome (HUS) is a newly recognized hematologic manifestation of HIV infection that may be triggered by local or systemic infections as well as by immunological disorders. We report the case of a 36-year-old HIV-positive man, an intravenous drug abuser who developed HUS during an episode of acute pancreatitis. Hematologic and clinical improvement occurred following 2 weeks of nonaggressive therapy including vitamin E and fresh-frozen plasma.

Acute Disease↗
PubMed1992

Inhibition by trains of subthreshold high-frequency stimuli: an experimental study in spatial limitation.

The aim of this study was to determine whether the spatial limitation of the inhibitory effect of subthreshold conditioning stimuli trains (TSc) could be overcome by their simultaneous emission through several electrodes surrounding the area where the suprathreshold extrastimuli (S2) are delivered. In seven anesthaetized open chest dogs the effective ventricular refractory period was determined before and after the introduction of unipolar cathodal TSc, using epicardial electrodes. TSc pulse frequencies tested were 100 Hz, 200 Hz, 400 Hz, 600 Hz and 800 Hz, and train intensity was 10% lower than the train diastolic threshold for every pulse frequency. S2 and TSc were delivered: (a) by the same electrode; (b) by two different electrodes 3 mm apart; and (c) TSc through six peripheral electrodes surrounding the central electrode that delivered S2 (heptapolar electrode). Trains of 400 Hz showed the highest diastolic threshold, permitting the use of the highest train intensities. When TSc and S2 were delivered through the same electrode the ventricle remained unexcitable during the entire cardiac cycle in six of the seven dogs. In turn, when TSc and S2 were delivered by two different electrodes, the effective ventricular refractory period (EVRP) could only be increased by greater than or equal to 10 ms in three of the seven dogs (18 ms, 62 ms and 10 ms). When TSc was delivered simultaneously through six peripheral electrodes the increments were higher (118 ms, 88 ms and 75 ms) in these three dogs, and there was one additional dog with 12 ms increments of of EVRP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The effects of selective stellate ganglion manipulation on ventricular refractoriness and excitability.

The effects of selective stellate ganglion stimulation or stellectomy on ventricular excitability were studied in 30 open chest mongrel dogs anesthetized with alpha-chloralose. The effective refractory period (ERP) and strength interval curves (stimulus intensity [S2] = twice the diastolic threshold [ERP], and 2, 3, 5, 7, and 14 mA) were determined using bipolar epicardial electrodes placed in the mid-anterior wall of the right ventricle (RV) and the mid-posterolateral wall of the left ventricle (LV) during left stellate ganglion stimulation (LSGSt, n = 8) or right stellate ganglion stimulation (RSGSt, n = 8), or after left stellectomy (LSGEx, n = 7) or right stellectomy (RSGEx, n = 7). LSGEx prolonged ERP-LV (172 +/- 9 vs 167 +/- 8 msec, P < 0.05) and ERP-RV (163 +/- 10 vs 158 +/- 14 msec, P < 0.05). RSGEx prolonged ERP-LV (168 +/- 17 vs 162 +/- 15 msec, P < 0.01) and ERP-RV (166 +/- 14 vs 160 +/- 13 msec, P < 0.01), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. LSGSt decreased ERP-LV (157 +/- 11 vs 163 +/- 12 msec, P < 0.01) and ERP-RV (147 +/- 18 vs 157 +/- 17 msec, P < 0.05), and the times of the strength interval curves obtained for each S2 intensity in both ventricles. RSGSt did not significantly decreased ERP-LV (152 +/- 11 vs 156 +/- 9 msec); however, it significantly shortened the times of the strength interval curves obtained for S2 intensities of 2 and 7 mA in the LV, and shortened ERP-RV (139 +/- 10 vs 145 +/- 7 msec, P < 0.01) and the times of the strength interval curve for S2 intensities of 2, 3, and 5 mA in the RV. A significant interaction (MANOVA test) was observed between the ventricle studied and the ganglion stimulated for S2 intensities of 2 and 3 mA, and between the effect of stimulation and the ganglion stimulated for S2 intensities of 3 and 14 mA. To conclude, selective stellectomy prolonged epicardial ventricular refractoriness in both the mid-anterior wall of the RV and the mid-posterolateral wall of the LV; the magnitude of the epicardial excitability variations in both areas was different during selective stellate ganglion stimulation.

Analysis of Variance↗
PubMed1991

Changes in canine ventricular refractoriness induced by trains of subthreshold high-frequency stimuli.

Epicardial electrodes were applied to 12 thoractomized dogs to determine the effects of trains of subthreshold conditioning stimuli (TSc) on ventricular refractoriness when delivered preceding a premature suprathreshold stimulus (S2). Several factors were analyzed: (1) the influence of TSc pulse frequency (100-900 Hz); (2) the delay between TSc and S2 (1 or 10 ms); (3) the distance between the electrodes for the emission of TSc and S2 (same electrodes or different electrodes at 3 mm); and (4) S2 current intensity (two- or fourfold diastolic threshold). The TSc (mean current intensity 0.33 mA, range 0.1-0.7) were found to significantly prolong the effective ventricular refractory period (EVRP) at all train pulse frequencies. The EVRP increment was progressively greater as pulse frequency was increased, the maximum EVRP increment being at 900 Hz (mean 50.8 +/- 32.3 ms; maximum increment 130 ms). On increasing S2 current intensity, the EVRP increment was less (maximum value 35 ms) and less consistent (in four of six dogs); in two cases the EVRP was shortened. The increase in delay between TSc and S2 attenuated the EVRP prolongation, which was present in only three of six dogs tested, and the EVRP was shortened in two dogs. There was no EVRP prolongation at any TSc pulse frequency when TSc and S2 were delivered at different electrodes. Thus TSc decreases myocardial ventricular excitability, prolonging EVRP in direct proportion to TSc pulse frequency. However, this property is limited by S2 current intensity as well as the time and distance between TSc and S2.

Animals↗
PubMed1991

Effects of atrial impulse timing on AV concealed conduction in the rabbit heart.

The influence of the timing of a nontransmitted or transmitted atrial impulse on the atrioventricular (AV) conduction time of the subsequent impulse was studied in nine isolated rabbit hearts. AV conduction curves were determined by applying the atrial extrastimulus test. The extrastimulus was delivered preceded or not by an interposed atrial impulse whose coupling interval with respect to the last atrial beat of a basic train was kept constant at 100, 120, 140, 160, 175, 200, 225, 250, and 300 msec. In all experiments, there was a "concealment interval," i.e., the AV effective refractory period was longer than the atrial functional refractory period, and in seven experiments was comprised between 100 and 160 msec. For any given extrastimulus coupling interval in the presence of an interposed nontransmitted atrial impulse, AV conduction time was significantly greater than in its absence; the increase was greater than the longer the nontransmitted atrial impulse coupling interval, i.e., the shorter the subsequent transmitted impulse coupling interval with respect to the previous interposed nontransmitted impulse. The AV conduction curves relating the extrastimulus AV conduction time to its coupling interval with respect to the last atrial impulse of the basic train fitted to a hyperbolic model both in the absence of the interposed atrial impulse and in its presence (mean square residual 31 +/- 23 msec2), and the interposed atrial impulse modified the constants of the functions; the slope of the linear transformations was progressively more negative as the interposed atrial impulse was delayed. Furthermore, the effects of the interposed atrial impulse--transmitted or not--on AV conduction time of the subsequent impulse were qualitatively similar, their magnitude depending on the time elapsed were qualitatively similar, their magnitude depending on the time elapsed between the two.

Animals↗
PubMed1991

Atrioventricular electrotonic interaction in complete atrioventricular block: an experimental model using radiofrequency energy in the rabbit heart.

UNLABELLED: Provided the conditions for electrotonic transmission exist, an automatic focus surrounded by a block zone may be externally modulated. The atrioventricular (AV) electrotonic interaction was studied in 16 perfused rabbit hearts with supra-Hisian complete AV block induced using low radiofrequency energy doses (2.5 watts; 10 seconds). In nine experiments the sinus node was preserved (group I), whereas in seven it was removed maintaining an AV nodal rhythm (group II). The V-V (ventricular cycle length) and V-A (coupling of the intervening atrial beat) in both groups, and also the A-A (atrial cycle length) and A-V (coupling of the intervening ventricular beat) intervals in group II, were measured beat by beat after current delivery. The phase response curves V-V versus V-A, and A-A versus A-V showed AV interaction in five experiments from group I, and in four from group II, as follows: (1) accelerating phase response curve, characterized by a pacemaker acceleration (V-V or A-A abbreviation) at a critical V-A or A-V coupling interval; maximum acceleration could be progressively (phase response curve without rapid cross-over) or briskly (phase response curve with rapid crossover) reached; from this point onwards acceleration decreased with a further increase in V-A or A-V coupling interval (acceleration slope). (2) Biphasic phase response curve, characterized by initial delaying and late accelerating phases. Maximum acceleration and the acceleration slope were both smaller in accelerating phase response curves without rapid cross-over. On reverting complete block in two experiments, a progressive increase in maximum acceleration and acceleration slope was observed. CONCLUSIONS: (1) AV interaction in complete AV block can be manifested as accelerating or biphasic phase response curves; (2) transition from electrotonic interaction to conduction seems to be a continuum.

Animals↗
PubMed1991

Measurement of maximal static respiratory pressures at the mouth with different air leaks.

The effect of two different circuit leaks on the measurement of maximal static inspiratory and expiratory pressures at the mouth (Pimax, Pemax) was assessed in 70 patients with respiratory disease. Patients were divided into three groups with similar anthropometric and spirometric characteristics. The first group (30 patients) had their Pmax measured with a leak of 2.0 mm internal diameter (ID) and 37 mm length (as proposed by T. Ringqvist) and repeated with a second leak of 1.0 mm ID and 15 mm length (as recommended by J. L. Clausen). The two measurements were done in random order. Measurements for the other two groups (20 patients each) were taken with one or another, the two leaks randomly alternated with no leak. Pimax measurements obtained with Ringqvist's leak were 17 percent (p less than 0.005) lower than those with Clausen's leak and 22 percent (p less than 0.005) lower than those with no leak. Pemax measurements performed with Ringqvist's leak in place were 11 percent (p less than 0.005) lower than those with Clausen's leak and 11 percent (p less than 0.005) lower than those obtained with no leak. The comparison between Clausen's leak and no leak showed no statistically significant difference. We conclude that whenever the effect of pressure generated in the mouth is to be avoided in the measurement of respiratory Pmax, a leak of the size proposed by Ringqvist is to be preferred.

Asthma↗
PubMed1991

Usefulness of carcinoembryonic antigen determination in bronchoalveolar lavage fluid. A comparative study among patients with peripheral lung cancer, pneumonia, and healthy individuals.

We compared carcinoembryonic antigen (CEA) levels in bronchoalveolar lavage (BAL) fluid and serum of patients with lung cancer, pneumonia, and healthy individuals to determine the usefulness of CEA in diagnosing lung cancer not visible endoscopically. Cancer patients had CEA lavage fluid levels (4,650 +/- 1,565 ng/mg of albumin) significantly higher than pneumonia patients (755 +/- 346 ng/mg) or healthy individuals, smokers (252 +/- 48 ng/ml), and non-smokers (175 +/- 6 ng/mg). In serum, CEA assay cannot discern between cancer (35 +/- 13 ng/ml) and pneumonia (4.6 +/- 1.4 ng/ml) (p = 0.06). Using 1,000 ng/mg of albumin as the cutting point in BAL fluid, sensitivity and specificity were 77 percent and 94 percent, respectively. In serum, 5 ng/ml provided a sensitivity of 55 percent and specificity of 91 percent. Positive and negative predictive values were 77 percent and 94 percent in BAL, respectively, and 62 percent and 89 percent in serum, respectively. Using a combination of serum and BAL fluid CEA levels, the sensitivity and specificity were 88 percent and positive and negative predictive values were 66 percent and 96 percent, respectively. When used in combination with serum levels of CEA or transbronchial biopsy, the diagnostic yield increased up to 88 percent. Thus, although CEA determination in BAL fluid improves diagnostic yield, it should not be used as the only diagnostic procedure.

Adult↗
PubMed1991

Active inspiratory impedance and neuromuscular respiratory output during halothane anaesthesia in humans.

The aim of this study was to measure, in 11 patients with healthy lungs, active inspiratory impedance during anaesthesia. In addition, we recorded changes in inspiratory occlusion pressure at 100 ms (P0.1) and ventilatory pattern while awake and during anaesthesia with a mean inspiratory fraction (FI) of 0.017 halothane in O2. The total active inspiratory resistance and elastance values were 5.4 +/- 3.3 hPa.l.1.s and 29.9 +/- 6.2 hPa.l.1, respectively. P0.1 and the ratio between P0.1 and mean inspiratory flow (P0.1/(VT/TI)) increased 124% (p less than 0.001) and 68% (p less than 0.001), respectively, during anaesthesia. Respiratory frequency rose significantly from 12.2 +/- 1.5 (mean +/- SD) to 24.6 +/- 4.6 cycles.min-1, while tidal volume and inspiratory duty cycle lowered significantly from 0.599 +/- 0.195 l and 0.44 +/- 0.04 to 0.372 +/- 0.088 l (p less than 0.001) and 0.40 +/- 0.04 (p less than 0.05), respectively. Minute ventilation (VE) and VT/TI did not change significantly. During halothane anaesthesia with an FI:0.017, the increase in neuromuscular respiratory output appears to compensate for the increased mechanical load, thus resulting in maintenance of VE at levels similar to those of an awake state.

Adult↗
PubMed1990

Transcatheter ablation of the sinus node in dogs using high-frequency current.

Sinus node ablation by high-frequency current (HFC) (0.7 MHz. 5-10 W), delivered through the distal electrode of a conventional endocavitary catheter, was induced in seven thoracotomized dogs under autonomic blockade. The HFC was delivered for variable periods of time under ECG monitoring, while sinus tachycardia was produced or after attaining sinus arrest. The procedure was repeated until a stable non-sinus rhythm was obtained. Sinus rhythm was abolished in all seven dogs after a variable number (7-20) of discharges. The escape rhythm obtained after the last discharge, characterized by means of epicardial electrodes and analysis of P-wave morphology, length of PR interval and the rate, showed an atrial activation pattern different from sinus rhythm in all cases. The P-wave was retrograde in two cases, and in one case no atrial activity was detected after the last discharge; however, atrial activity recovered after 35 min, the activation pattern being different from the controls. After 2 h, sinus rhythm had not returned in any case. In no case was there perforation of the atrial wall. Acute histological findings showed coagulation necrosis of the endocardium, extending to the muscle fibres and affecting the sinus cells.

Animals↗
PubMed1990

Closed chest radiofrequency ablation of the sinoatrial node in dogs.

UNLABELLED: Transcatheter ablation of the sinoatrial node with radiofrequency energy (0.6 MHZ, 2.5-5 watts) was performed in 10 dogs under fluoroscopic monitoring and autonomic blockade. Sinus function was previously studied in terms of cycle length, recovery time and atrial activation pattern by catheter mapping. Several discharges (8-22) were applied for variable periods of time (maximum 1 minute). Sinus tachycardia and/or sinus arrest during ablation confirmed correct catheter position. Sinus rhythm was abolished in eight dogs. The ectopic rhythm was atrial in six and AV nodal in two dogs. Ectopic atrial cycle length and recovery time were longer than the baseline sinus values: 724 +/- 321 versus 509 +/- 147, P less than 0.05; 1103 +/- 775 versus 618 +/- 151, P less than 0.05 (values in msec). The study was repeated 10-14 days later in six dogs; three maintained the same atrial rhythm, one persisted in sinus rhythm, and one dog changed from atrial to sinus rhythm, whereas another changed from sinus to atrial rhythm. Gross findings revealed transmural lesions in all dogs, without perforation. Histology in chronic dogs showed sinus cell necrosis and its replacement by granulation tissue. IN CONCLUSION: sinus function may be abolished by closed chest radiofrequency ablation.

Animals↗
PubMed1990

Respiratory input impedance in anesthetized paralyzed patients.

Respiratory impedance (Zrs) was measured between 0.25 and 32 Hz in seven anesthetized and paralyzed patients by applying forced oscillation of low amplitude at the inlet of the endotracheal tube. Effective respiratory resistance (Rrs; in cmH2O.l-1.s) fell sharply from 6.2 +/- 2.1 (SD) at 0.25 Hz to 2.3 +/- 0.6 at 2 Hz. From then on, Rrs decreased slightly with frequency down to 1.5 +/- 0.5 at 32 Hz. Respiratory reactance (Xrs; in cmH2O.l-1.s) was -22.2 +/- 5.9 at 0.25 Hz and reached zero at approximately 14 Hz and 2.3 +/- 0.8 at 32 Hz. Effective respiratory elastance (Ers = -2pi x frequency x Xrs; in cmH2O/1) was 34.8 +/- 9.2 at 0.25 Hz and increased markedly with frequency up to 44.2 +/- 8.6 at 2 Hz. We interpreted Zrs data in terms of a T network mechanical model. We represented the proximal branch by central airway resistance and inertance. The shunt pathway accounted for bronchial distensibility and alveolar gas compressibility. The distal branch included a Newtonian resistance component for tissues and peripheral airways and a viscoelastic component for tissues. When the viscoelastic component was represented by a Kelvin body as in the model of Bates et al. (J. Appl. Physiol. 61: 873-880, 1986), a good fit was obtained over the entire frequency range, and reasonable values of parameters were estimated. The strong frequency dependence of Rrs and Ers observed below 2 Hz in our anesthetized paralyzed patients could be mainly interpreted in terms of tissue viscoelasticity. Nevertheless, the high Ers we found with low volume excursions suggests that tissues also exhibit plasticlike properties.

Adult↗
PubMed1990

The pattern of resting breathing in patients with upper airway obstruction.

The flow-time curve of resting breathing was recorded in 14 patients (aged 36 +/- 16 yrs) with mild to moderate symptoms of upper airway obstruction (UawO) and compared to that of 28 matched, healthy controls (HC) in order to characterize the breathing pattern of such patients. The inspiratory time over total time (TI/Ttot) was higher in the patients (0.42; SD 0.04) than in HC (0.37; SD 0.04) (p less than 0.001), and tidal volume (VT) over TI was lower in patients (0.37; SD 0.07 l.s-1) than in HC (0.43; SD 0.09 l.s-1) (p less than 0.01). Inspiratory and expiratory peak flows at rest were also lower in the patients (p less than 0.001). In these, the mean to peak flow ratio of inspiration (0.74; SD 0.07) was higher than in HC (0.66; SD 0.04) (p less than 0.0005). This indicates a more rectangular wave of inspiration in the patients. All of these changes may be due to the increased inspiratory load. However, since the patients were breathing at rest with VT and flows far below their values on the maximal flow volume loop, the changes can also be interpreted as adaptive rather than imposed by absolute mechanical limitations.

Adult↗
PubMed1989

Induction of complete AV block in dogs by transcatheter ablation using high-frequency current: an alternative to direct-current high energy shock.

The utility of high-frequency current applied through the distal electrode of a conventional electrode-catheter for altering atrio-ventricular conduction was studied in 18 anaesthetized dogs. Following adequate unipolar His bundle recording, current was applied over periods of 20-30 s, with an output power of 30 W. Complete AV block was achieved in all dogs (four dogs on the third attempt, five on the second, and nine on the first). Ten of the dogs were killed after four hours of continuous ECG monitoring (Group I); examination revealed circumscribed spheroidal myocardial lesions at the base of the right atrium over the posterior tricuspid valve; no thrombus formation was encountered. The remaining eight dogs (Group II) were kept alive for three months during which complete block persisted in all cases. The histologic study showed partial replacement of AV nodal and His bundle tissues and myocardium by fibrous tissue. In conclusion, electro-catheter ablation using high-frequency energy is effective for producing complete AV block. The resulting lesions are circumscribed. This method may prove to be an alternative to the transcatheter DC shock for ablation of the AV conduction system.

Animals↗