Is management of anesthesia in achondroplastic dwarfs really a challenge?

STUDY OBJECTIVE: To review our eight-year anesthetic experience with achondroplastic patients. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS: 15 achondroplastic patients who underwent 53 surgical procedures of orthopedic surgery between 1987 and 1994. INTERVENTIONS: Anesthetic technique, drugs, number of incidents, and complications in the intraoperative and postoperative period were recorded. MEASUREMENTS AND MAIN RESULTS: Adequate premedication before the transfer to the operating room was very useful to reduce anxiety and increase cooperation. Inhalation induction was well tolerated and allowed easy peripheral venous cannulation. Only one patient presented difficulties during intubation (on two occasions). In the other patients, we found small difficulties only during ventilation with a face mask, which was easily corrected by modifying the position of the patient and/or inserting an oropharyngeal airway. No adverse effect was identified for any particular anesthetic drug or technique used. CONCLUSIONS: Although the characteristic deformities of achondroplastic patients can impede the management of anesthesia, in our study we found no special difficulties. Airway complications did not occur. Thus, no specific optimal anesthetic regimen can be recommended.

Combination of ondansetron and droperidol in the prophylaxis of postoperative nausea and vomiting.

The aim of this study was to compare the efficacy and safety of ondansetron plus droperidol with each drug alone or placebo in the prevention of postoperative nausea and vomiting (PONV). One hundred females, aged 18-65 yr, ASA physical status I-II, undergoing general anesthesia for elective abdominal surgery were included in a prospective, double-blind, placebo-controlled, randomized study. A standardized anesthetic technique and postoperative analgesia (ketorolac plus patient-controlled analgesia [PCA] with morphine) were used in all patients. Patients were randomly assigned to receive placebo (Group 1, n = 25), droperidol 2.5 mg with induction of anesthesia and 1.25 mg 12 h later (Group 2, n = 25), ondansetron 4 mg with induction (Group 3, n = 25), and ondansetron plus droperidol at the same doses as Groups 3 and 2, respectively (Group 4, n = 25). A complete response, defined as no PONV in 48 h, occurred in 28% of patients in Group 1, 60% in Group 2 (P < 0.05 vs Group 1), 56% in Group 3 (P < 0.05 vs Group 1), and 92% in Group 4 (P < 0.01 vs Groups 1, 2, and 3). Sedation was significantly greater with droperidol (Groups 2 and 4) for 12 h postoperatively. In conclusion, the combination of ondansetron plus droperidol was more effective than each antiemetic alone or placebo in the prevention of PONV in women undergoing elective abdominal surgery.

[Reduction of the need for blood derivatives in liver transplantation using aprotinin]. / Reducción de los requerimientos de hemoderivados en el trasplante hepático con aprotinina.

OBJECTIVES: To evaluate the efficacy of aprotinin in reducing the need for blood products in orthotopic liver transplantation. PATIENTS AND METHODS: Blood product needs and coagulation test results were studied in 42 adults with cirrhosis of the liver who received orthotopic liver transplants. The first 16 liver transplants carried out without aprotinin (control group) were compared with the next 26 consecutive transplant patients who received aprotinin. Each of the first 9 received a loading dose of 2 million units that was followed by the infusion of half a million units per hour until the end of surgery. The next 17 received the same infusion dose at the same rate but no loading dose. RESULTS: Patients who received aprotinin required fewer transfusions of blood products (5.3 units of packed red blood cells as opposed to 13 units; 9 units of fresh frozen plasma versus 14.6 units; 1.7 units of platelets versus 4.2 units; and 3.8 units of cryoprecipitates versus 8.8 units). We observed a marked reduction of fibrinolysis (less increase in D dimers after removal of the liver when aprotinin was used. CONCLUSIONS: Prophylactic use of aprotinin during surgery has a beneficial effect on hemostatic mechanisms, reducing the need for blood products. A reduction in fibrinolysis seems to contribute to this effect.

[Does propofol have advantages over midazolam and isoflurane? Comparative study of 2 total intravenous anesthesia techniques using midazolam and propofol, versus balanced anesthesia with isoflurane]. / Tiene ventajas propofol sobre midazolam e isoflurano? Estudio comparativo de dos técnicas de anestesia total intravenosa con midazolam y propofol, y anestesia balanceada con isoflurano.

OBJECTIVES: To compare two techniques for total intravenous anesthesia (TIVA): midazolam-alfentanil-flumazenil and propofol-alfentanil, contrasting them with combined anesthesia (thiopental-isoflurane-alfentanil) and assessing the efficacy of flumazenil in continuous perfusion for preventing resedation in TIVA with midazolam. PATIENTS AND METHODS: The efficacy and clinical tolerance of the 3 anesthetic techniques with propofol, midazolam or isoflurane were studied in 63 patients undergoing elective breast, lumbar or gynecological surgery. Anesthetic induction was achieved with midazolam 0.3 mg/kg-1 (group M), propofol 2.5 mg/kg-1 (group P) or thiopental 3 mg/kg-1 (group I); all patients also received 50 micrograms/kg-1 alfentanil and vecuronium bromide 0.12 mg/kg-1/h-1. Maintenance was achieved with midazolam in perfusion at 0.12 mg/kg-1/h-1 (group M); propofol in perfusion at 7 mg/kg-1/h-1 and a pre-incision dose of 1.5 mg/kg-1 (group P); and isoflurane at 1.15% (group I). The 3 groups also received one pre-incision dose of alfentanil 25 micrograms/kg-1 and post-incision perfusion at 60 micrograms/kg-1/h-1. The infusion of alfentanil was changed by amounts of 20 micrograms/kg-1/h-1 in accordance with the patient's response to surgery. After surgery patients in group M received flumazenil 0.5 mg i.v. over 30 sec and a perfusion of flumazenil 0.5 mg over 60 min. Parameters indicating efficacy were: 1) total dose and timing of alfentanil; 2) number of instances of inadequate anesthesia; 3) peri-operative amnesia; 4) times of awakening and extubation after surgery, and 5) the number of patients in each group who required naloxone. Parameters indicating tolerance were: 1) hemodynamic variables; 2) the number of postoperative desaturations; 3) level of sedation, comprehension and motor coordination and orientation; 4) the "G/g detection" test and the memory recall test; 5) adverse side effects; 6) need for postoperative analgesia, and 7) evaluation of the anesthetic technique. RESULTS: The 3 techniques afforded effective control of hemodynamic response to intubation and surgical incision. Anesthetic maintenance was easy and safe with isoflurane and propofol. Higher doses of alfentanil, however, were needed with midazolam and we found a higher incidence of signs of superficial anesthesia. Reversion of midazolam with flumazenil 0.5 mg i.v. produced earlier awakening, although this was followed later by relapse into hypno-sedation that could not be prevented with a perfusion of flumazenil. Although recovery from anesthesia was slower with propofol than with isoflurane, we observed no differences in level of sedation, motor coordination and postoperative comprehension. Maintenance with isoflurane produced a higher incidence of adverse side effects such as tremors and nausea after surgery. CONCLUSIONS: None of the TIVA techniques proved superior in all the parameters studied during anesthetic maintenance when compared with balanced isoflurane-alfentanil, although the propofol-alfentanil combination was found to be superior to that of midazolam-alfentanil. After anesthesia, however, recovery was better with the association of propofol-alfentanil and adverse side effects were fewer. Flumazenil at the doses used was ineffective for preventing resedation due to midazolam.

[Ambulatory pediatric anesthesia: preanesthetic evaluation, anesthetic techniques, and immediate postoperative care]. / La anestesia pediátrica ambulatoria: evaluación preanestésica, técnicas anestésicas y postoperatorio inmediato.

The advantages of pediatric out-patient surgery are: 1) greater psychological ease; 2) lower rate of infection; 3) less impact on patient habits, and 4) lower cost. Surgery must not involve organs, must have a low rate of complications, and be short. The preanesthetic interview should include clinical history and complementary examinations, information on anesthetic technique, perioperative recommendations and psychological preparation of parents and child. Detailed information reassures parents and improves collaboration; their presence during induction may be useful. At this time complete fasting is not recommended; although solids are not permitted, clear liquids should be taken up to 2-3 hours before anesthesia. In this way the child is less irritable and hypoglycemia and hypotension during inhalational induction are prevented. Low doses of midazolam and ketamine have been used for premedication, which though possibly useful, is not recommended because recovery may be prolonged. Halogenated anesthetics are very useful, with nitrous oxide providing an excellent complement. The potentially toxic effect of halothane on the liver does not keep this agent from being the most popular. Recovery is fast with any of the usual hypnotics (etomidate, propofol, thiopentone). Although thiopentone continues to be the hypnotic drug of reference, propofol's versatility is causing it to gain wider acceptance. The use of atracurium or vecuronium is justified if the dose is adjusted in keeping with type of surgery and duration. Intraoperative analgesics include meperidine, fentanyl and alfentanyl; morphine is not recommended. Should tracheal intubation be necessary, laryngeal edema may be avoided by gentle, cautious laryngoscopy, the use of a tube without a balloon, and 3 h of postanesthetic observation. A laryngeal mask may serve as an alternative to tracheal intubation. Local-regional anesthesia, excepting epidural and spinal anesthesia, offers a number of advantages: blockade of nociceptive stimuli, avoidance of opioid drugs, rapid and pleasant awakening (excellent for postoperative analgesia), and less need for postoperative analgesics. The postoperative complications seen most often are related to respiration or hypertension, making routine postanesthetic pulse oximetry a recommendation. The most frequently used analgesics are paracetamol, magnesium dipyrone, diclofenac, ketorolac, or codeine compounds. Although the incidence of nausea and vomiting is low in children, they are frequently a cause of hospitalization. Inappropriate postoperative care can increase the rate of admissions and medico-legal problems.(ABSTRACT TRUNCATED AT 400 WORDS)

[Comparative study between thiopental and propofol in short-duration anesthesia]. / Estudio comparativo entre tiopental y propofol en anestesias de corta duración.

In a randomized study, 80 healthy unpremedicated female patients were included. For short gynaecological procedures (curettage) they were anaesthetized with either propofol 2 mg/kg (n = 40) or thiopentone 5 mg/kg (n = 40) in combination with nitrous oxide/oxygen (1/1). Supplementary doses of propofol (25 mg) or thiopentone (50 mg) were given when necessary during the procedure. Propofol caused a significant fall in arterial blood pressure (greater than thiopentone in diastolic pressure) and a decrease in heart rate (thiopentone did not change heart rate). Discomfort on injection was similar in both groups. Recovery times were shorter in propofol group: Patients opened their eyes at 1.3 minutes, were awake at 2.2 minutes and could seat with no help at 5.2 minutes. In the thiopentone group, there was a greater incidence of nausea. Propofol was associated with euphoria, "clear-headedness" and pleasant dreams more than thiopentone. We conclude that propofol is a good alternative to thiopentone in short operative procedures.

[Midazolam in anesthesiology]. / Midazolam en anestesiología.

Midazolam (MDZ) (8-chloro-6(2-fluoropheny 1)-1-methyl-4H-imidazol-[1,5a] [1,4]benzodiazepine) is an "annelated" benzodiazepine (BZDs) synthetized in 1976, characterized differently with the "classical" BZDs by a five-membered heterocycle fused on position 1,2 of the diazepine nucleus. This fused imidazol ring modifies the properties inherent in the "classical" BZDs in at the least three aspects: solubility, metabolisation and the stability in aqueous solution. MDZ, having similar properties with the "classical" benzodiazepines, has better local tolerance, faster onset of action, greater plasmatic clearance, shorter half-life elimination (1.7-2.4 hr) with no active metabolites. With a bioavailability of 92% (IV), 82-91% (IM) and 50-52% "per os", the CNS effects of MDZ are similar in all three ways. In anesthesiology we can administer MDZ as an anesthetic premedication ("per os", IM or IV), anesthetic induction and maintenance and IV sedation in locorregional anesthetic procedures or diagnostic and therapeutic explorations. MDZ has a great safety margin, moderate respiratory and cardiovascular effects and lacks of teratogenic or embryotoxic effects.