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Biomedical subjects

M García-Guiral

Publications and source records attributed to M García-Guiral.

9 recordsLinked to original sources

[Relationship between laryngoscopy degree and intubation difficulty].

OBJECTIVES: To determine the relation between difficult intubation and grade of direct laryngoscopy, as well as the factors that influence them, and prognosis. PATIENTS AND METHOD: In 1,336 patients receiving general anesthesia, seven airway measurements were made to reflect degree of difficulty and predictive value of presurgical tests on direct laryngoscopy and intubation. RESULTS: The incidences of difficult laryngoscopic and intubation procedures were 1.4 and 3.0%, respectively. Difficult intubation was more frequent in women and in patients between 40 and 65 years of age (p < 0.05). In 105 intubations (64.8%) performed with moderate difficulty (use of a stylette, external laryngeal pressure or two tries) and 17 (41.5%) performed with difficulty (three or more tries), the laryngoscopic procedure was graded as easy (Cormack-Lehane grade I-II). In these cases (easy laryngoscopy with moderate/difficult intubation), the causes recorded were size of endotracheal tube in comparison with the laryngeal opening (n = 11); anterior glotis (n = 36); insufficient relaxation (n = 31); disease in or beyond the vocal cords (n = 29); or undetermined (n = 15). In the easy intubation cases, the laryngoscopic procedures were grade III in 2.9%. Intubation was difficult in 16.3% (n = 39) of patients presenting some type of abnormality upon examination of the airway (p < 0.05). The airway characteristic that best predicted laryngoscopic difficulty was extension of the lower neck to 90 degrees (relative risk of 4.46), mouth opening less than 3.5 cm (3.92), presence of two airway abnormalities (4.25) and presence of three or more abnormalities (5.39) (p < 0.01). CONCLUSION: The fact that cases of easy laryngoscopy coincide with difficult intubation suggests that, to the degree of intubation difficulty must be added extrinsic factors (individual skill, maneuvers performed, instrumentation, relaxation of the laryngeal musculature and others) that are hard to standardize and reflect when predicting an intubation by the grade of difficulty in laryngoscopy.

Adolescent↗

[Brachial plexus anesthesia: results of a modified perivascular supraclavicular technique].

OBJECTIVES: To compare a modified supraclavicular perivascular approach with the axillary perivascular technique for providing brachial plexus blockade. PATIENTS AND METHODS: We studied 100 ASA I/II patients undergoing surgery on upper extremities. Patients were divided into two groups: group 1 (axillary, n = 50) and group 2 (modified supraclavicular, n = 50 ). Patients needing shoulder surgery were excluded from group 1. In both groups 35 ml of 1.5% mepivacaine plus 0.05 mEq/ml of bicarbonate was used. The Winnie axillary perivascular technique was used in group 1. In group 2 we used a modification of the lateral perivascular supraclavicular technique described by Brown, with the needle directed cephalad, medial and posterior to provide paresis in the upper extremity. We recorded the degree of difficulty and time needed for each technique, time until start of paresis and time of motor paralysis in the extremity, area of nerve deficit, and quality of block. In group 2 we measured the depth of paresthesia. Perioperative complications were noted for each group. RESULTS: There were no significant differences in difficulty, time or quality of block. Time until start of paresis and time of motor paralysis were significantly shorter in group 2 (12.0 +/- 2.5 versus 4.9 +/- 0.2 min, and 15.2 +/- 6.9 min versus 35.3 +/- 5.2, in groups 2 and 1, respectively). Mean depth of paresthesia was 44.1 +/- 5.2 min. The most frequently recorded complications were Horner's syndrome in group 2 and vascular puncture in group 1. CONCLUSIONS: The modified perivascular lateral supraclavicular technique is a safe, effective method for providing brachial plexus block.

Adult↗

[Intraoperative arrhythmias in a patient with mitral valve prolapse].

We report a case of mitral valve prolapse in which the first manifestation was the occurrence of arrhythmias during anesthesia. A 28 years old female patient, ASA I, without previous medical or surgical history was programmed for surgical repair of an anal fistula. Preoperative physical and laboratory examination were normal. During anesthetic induction with propofol and droperidol and coinciding with orotracheal intubation the patient developed ventricular premature beats, bigeminy, and runs of ventricular tachycardia which were controlled with intravenous lidocaine. Anesthesia was maintained with 66% of O2/N2O, 0.5 to 1% of isoflurane, alfentanil, and atracurium. At the beginning of the intervention the patient presented an episode of supraventricular tachycardia at a rate of 140 to 160 beats/min which did not respond to a deeper anesthetic level nor to the administration of 5 mg of verapamil. This arrhythmia was finally interrupted with 3 mg of propranolol and it did not relapse during the surgical procedure. We discuss the physiopathology of the lesion, the possible arrhythmic effect of the anesthetic agents used in this case, and the effects of several pathologic situations (anemia, pain, anxiety, hypovolemia, etc) documented in patient with this abnormality.

Adult↗

[Use of high doses of aprotinin in cardiac surgery].

OBJECTIVES: To study the efficacy of aprotinin in reducing whole blood loss after cardiac surgery with extracorporeal circulation. PATIENTS AND METHODS: Two groups of patients undergoing cardiac surgery with extracorporeal circulation were studied. Group I (n = 51) received 2 x 10(6) KIU (kallikrein inhibiting units) of aprotinin upon anesthetic induction, a similar dose in the extracorporeal circulation priming pump, and a maintenance dose of 500,000 KIU/h until removal from the operating theater. Group II (n = 51) was the control group. Patients that had previously undergone surgery with extracorporeal circulation were excluded, as were those being treated with anti-coagulants or anti-aggregants. Data recorded were blood volume, transfusions needed in the first 24 h, and blood derivatives used throughout the hospital stay. Postoperative kidney function was also determined. The occurrence of acute myocardial infarction in patients undergoing myocardial revascularization was also noted. RESULTS: Group I required a mean of 2.40 U of concentrated red blood per patient during the first postoperative day, as opposed to a mean of 4.3 U in group II (p < 0.001). Blood loss through drains was also less in group I than in group II (431.82 vs 895.29 ml; p < 0.001). Total blood needed during the hospital stay was 3.50 units per patient in group I vs 5.40 U in group II (p < 0.001). Urea and creatinine were similar in the two groups before and after surgery (p = NS), and there were no significant differences in the number of cases of acute myocardial infarction in the two groups (3 in group I and 2 in group II). CONCLUSIONS: Administration of high doses of aprotinin is an effective technique for reducing the need for whole blood in patients requiring extracorporeal circulation during surgery. The technique does not compromise kidney function or increase the risk of perioperative acute myocardial infarction.

Adult↗

[Premedication with clonidine in the neurosurgical patient: sedation, anesthetic requirements and hemodynamic perfusion].

OBJECTIVES: To analyze the effect of premedication with clonidine on postoperative sedation, anesthetic requirements and hemodynamic repercussions in patients undergoing craniotomy due to supratentorial intracranial pathology. PATIENTS AND METHODS: Twenty ASA I/II patients in a double-blind prospective study were assigned randomly to receive lorazepam (0.03 mg/kg/po, n = 10) or clonidine (0.005 mg/kg/po, n = 10) the night before and 90 minutes before surgery. Arterial pressure and heart rate were monitored continuously during and immediately after surgery (first 24 hours). Anesthetic induction was achieved with thiopental (maximum 6 mg/kg) and maintained with O2/N2O and an infusion of alfentanyl (1 microgram/kg/min). Hemodynamic response to surgical stimulus was treated with additional boluses of alfentanyl up to a maximum dose of 0.1 mg/kg and with an increase in infusion dosage to 2 micrograms/kg/min. When these were ineffective, isoflurane was given. All patients were extubated in the operating room. RESULTS: No differences in level of sedation were found between the two groups. The infusion dose and total amount of alfentanyl given were smaller for patients treated with clonidine (0.8 +/- 0.04 vs 0.6 +/- 0.01 microgram/kg/min and 22.4 +/- 5.3 vs 17.5 +/- 4.9 mg, respectively) (p < 0.05). No differences were found in isoflurane requirements (5/5 vs 2/8). Mean arterial pressure and heart rate were lower with clonidine from 3 minutes after intubation until the patient's arrival in the recovery room (p < 0.05), with marked bradycardia (49 +/- 5 vs 73 +/- 7 bpm) (p < 0.05) upon intubation. CONCLUSIONS: Premedication of neurosurgical patients with clonidine offers no advantages over lorazepam with respect to sedation. Nevertheless, clonidine may offer advantages with respect to the amount of alfentanyl required and attenuation of perioperative adrenergic response.

Adult↗

[Oral premedication with clonidine in patients undergoing coronary revascularization surgery].

OBJECTIVES: To analyze the effect of premedication with clonidine on level of sedation, anesthetic requirements and hemodynamic repercussions in patients undergoing coronary revascularization. PATIENTS AND METHODS: Thirty patients were divided into two groups and randomly assigned for premedication with clonidine 0.005 mg/kg p.o. (C) or lorazepam 0.03 mg/kg p.o. (L), along with morphine 0.15 mg/kg i.m. and scopolamine 0.005 mg/kg i.m. in a prospective double-blind study. The level of sedation before surgery and anesthetic requirements in the two groups were compared, as were systolic and diastolic arterial pressure, heart rate and hemodynamics during and after surgery. Fentanyl was used for anesthetic induction in boluses of 0.15 mg every 10 seconds; maintenance boluses of 0.5 mg were used up to a maximum dose of 0.07 mg/kg. If hemodynamic variables analyzed (systolic and diastolic arterial pressure and heart rate) were not kept within 30% of baseline values with this regimen, isoflurane was added. RESULTS: No differences between the two groups were found for level of sedation. The total dose of fentanyl was lower in group C (0.052 +/- 0.002 mg/kg vs 0.058 +/- 0.002 mg/kg) (p < 0.05). The number of patients requiring isoflurane was similar (4/11 and 6/9) in both groups. The hemodynamic profile prior to extracorporeal circulation (ECC) revealed arterial pressures and heart rates to be lower in the group treated with clonidine (p < 0.05); after ECC systemic resistance in group C was lower (630 +/- 103 vs 795 +/- 106 din.s.cm-5) (p < 0.05) and this was not compensated for by a significant rise in cardiac index (2.62 +/- 0.09 vs 2.40 +/- 0.08 l/min/m2) at similar occlusion pressures. CONCLUSIONS: Use of clonidine in the type of patient studied does not improve the level of sedation over that achieved with lorazepam. Fentanyl requirements decreased with clonidine. With respect to hemodynamic profile, systemic vascular resistance fell in the clonidine group after removal of ECC, and thus this drug offers no advantages for routine premedication.

Administration, Oral↗