Maurice Lippmann

Cardiovascular Effects of Anesthetic Induction with Ketamine

Anesthetic induction with ketamine has been reported to maintain or improve cardiovascular performance in severely ill patients. Using invasive cardiovascular monitoring, we studied physiologic responses to a single dose of ketamine in 12 critically ill patients. Six patients demonstrated decreases in ventricular contractility, and four had decreases in cardiac output. Mean arterial blood pressure decreased in four patients. Pulmonary venous admixture increased in four of six patients, while oxygen consumption decreased in eight of 11 patients. Thus, a single dose of ketamine produced decreases in cardiac and pulmonary performance and in peripheral oxygen transport in this group of patients. It is proposed that in severely ill patients, preoperative stress may alter the usual physiologic responses to ketamine administration, and adverse effects may predominate. Ketamine, therefore, should be used with caution for induction of anesthesia in critically ill and in acutely traumatized patients until additional studies and further information on cardiovascular responses to ketamine are available.

Stent-graft migration following endovascular repair of aneurysms with large proximal necks: anatomical risk factors and long-term sequelae.

Purpose: To evaluate the outcome of aortic endografts deployed in large infrarenal necks and to identify any association of preoperative aneurysm characteristics and postoperative morphological changes with the incidence of neck dilatation and device migration in this patient subset. Methods: The records of 47 patients (41 men; mean age 74, range 55–84) with large aortic neck diameters treated with Talent stent-grafts from 1998 to 2001 were reviewed. Patients with anatomical criteria that precluded aneurysm exclusion with currently available devices were preferentially selected. Mean baseline aneurysm morphology included 27.6-mm (range 18–33.4) suprarenal and 28.1-mm (range 24–34) infrarenal neck diameters; the infrarenal neck length was 26 ± 16 mm with angulation of 37° ± 18°. Computed tomographic (CT) angiograms up to 3 years were analyzed using specialized interactive software; migration was defined as >1-cm change in the distance from the lower renal artery to the top of the device. Pre- and postoperative morphological characteristics of the aneurysm were compared between patients with and without migration. Results: Of the 45 patients successfully treated, 40 had complete CT data for analysis. During a mean 17-month follow-up, 7 (17.5%) of the 40 devices exhibited distal migration. Six patients required secondary procedures; 5 were in the migration cohort. No preoperative anatomical characteristic or degree of neck dilatation over time was predictive of stent-graft migration. Aneurysm sac regression was significant at 1 (–0.09 ± 4.90 mm) and 2 (–1.48 ± 2.56 mm) years in endografts without migration (p<0.001). Distal endograft migration >1 cm predicted the need for secondary interventions (p<0.001), with 83% sensitivity and 94% specificity. Conclusions: Endovascular repair is successful in patients with large infrarenal necks and complex neck morphology. Changes in aneurysm remodeling over time were similar to reported observations in patients with more favorable neck criteria. Although no anatomical factor associated with migration could be identified from this analysis, distal displacement >1 cm correlated with the need for a secondary intervention.

Sequential cardiorespiratory patterns of anesthetic induction with ketamine in critically ill patients

Hemodynamic and O2 transport effects of ketamine anesthesia were evaluated in 22 critically ill patients. After placement of radial and pulmonary artery catheters, simultaneous measurements were made of cardiac output, intravascular pressures, arterial and mixed venous gases, saturations, pH, and Hct; cardiorespiratory values then were calculated for a preinduction control period and sequentially at frequent intervals over a 15-min observation period. In general, there was an early progressive increase in HR, cardiac index (CI), arterial and venous pressures, stroke work, and O2 delivery (Do2); O2 consumption (Vo2) and O2 extraction (O2 Ext) decreased. In general, ketamine produced an inotropic cardiac response, but these responses were not uniform; a relatively small percentage had reduced pressures, flow, and reduced myocardial performance that were related to hypovolemia and associated medical conditions.

Ventricular arrhythmias after epinephrine injection in enflurane and in halothane anesthesia.

&NA; The use of subcutaneous epinephrine during anesthesia is a common clinical practice for providing surgical hemostasis. In studies with 100 patients given either enflurane or halothane, with or without subcutaneous epinephrine, the incidence of ventricular ectopy in patients receiving halothane without epinephrine was 3 percent, while in those given epinephrine with halothane, the incidence was 7 percent. Those who received enflurane alone had no ectopic beats, while ventricular ectopy with enflurane and epinephrine resulted in an incidence of 1 percent. The authors conclude that enflurane anesthesia with concomitant administration of subcutaneous epinephrine is safe, provided the safeguards previously established for use of epinephrine with halothane are observed.

Multidose/Observational, Comparative Clinical Analgetic Evaluation of Buprenorphine

Abstract: Ninety‐eight patients completed a double‐blind, multidose, randomized parallel study in which buprenorphine (Temgesic) was compared to morphine. Drugs were administered at approximately equipotent intramuscular doses for a maximum of three days for the relief of moderate to severe postoperative pain. The two drugs exhibited similar profiles with pain relief evident at ½ hour, peaking at 1 hour, and decreasing to slight relief at 4–5 hours, with no significant differences for time to remedication. The most frequent side effect was somnolence. One patient suffered sudden chest pain shortly after an injection of morphine, and one patient had moderate hypoventilation after buprenorphine; both patients recovered uneventfully. Overall, both drugs provided good or excellent analgesia in 80 per cent of the patients in this unique multidose/observational study. Thus, these data and the reported lack of withdrawal symptoms and the absence of physical dependence liability suggest that buprenorphine may have a role in the management of chronic pain.

Anesthetic management of pulmonary lavage in adults.

A 6-year experience in the anesthetic management of 34 successful whole-lung lavages on 11 adult patients with pulmonary alveolar proteinosis is described. All patients were radio-graphically, physiologically, and symptomatically improved after the procedures.The anesthetic protocol for lung lavage includes: (1) unilateral whole-lung lavages 2 to 4 days apart; (2) general anesthesia with the placement of a Carlens tube; (3) isotonic saline as the lavage solution; (4) mechanical chest percussion during lavage; (5) serial arterial blood-gas determination and measurement of lung compliance in the intraoperative and immediate postlavage period.The authors conclude that whole-lung lavage is a safe and effective palliative procedure in pulmonary alveolar proteinosis and in the treatment of patients with pulmonary disease, such as cystic fibrosis or asthma, in which filling of the lung acini by liquid or solid material impairs oxygenation of the pulmonary capillary blood.

Neuromuscular Blocking Effects of Tobramycin, Gentamicin, and Cefazolin

Forty patients (A. S. A. class I or II), 18 to 75 years of age, who were undergoing elective surgery were studied to determine the clinical and subclinical neuromuscular blocking effects of two antibiotics, tobramycin and gentamicin and to compare these effects with those produced by cefazolin, an aminoglycoside not known to produce paralysis. Patients were prospectively and randomly assigned in approximately equal numbers to one of four groups: group A received 1 mg/kg of tobramycin; group B, 1 mg/kg of gentamicin; group C, 500 mg of cefazolin; or group D, control (no antibiotic). Antibiotics were administered intravenously 45 minutes immediately preceding the study. The ulnar nerve was stimulated supramaximally and neuromuscular function was measured electromyographically. Anesthesia was induced with thiopental, 4 mg/kg IV, and maintained with endotracheal enflurane 1.0% to 1.5% (inspired) and N2O-O2 (2 L: 1 L) after intubation. Succinylcholine (1 mg/kg) was administered after induction of anesthesia and the magnitude and duration of neuromuscular block monitored. d-Tubocurarine (0.1 mg/kg) was given 5 to 10 minutes after full recovery from succinylcholine and repeated as required. At the end of the operation, atropine, 0.02 mg/kg, and neostigmine, 0.4 mg/kg, were used to reverse the block. Base line neuromuscular data, duration of block of succinylcholine, and potency, duration of block, recovery rate, train-of-four fade, tetanic trend, response to double stimuli, post-tetanic effect, and reversibility of the subsequent d-tubocurarine-induced neuromuscular block were not significantly different (p < 0.01) between any two groups. Tobramycin gentamicin and cefazolin, in recommended single doses, lack clinical neuromuscular blocking and subclinical relaxant-potentiating effects.

Hemodynamics with propofol: is propofol dangerous in classes III-V patients?

rial oxygen saturation 100%). The surgical procedure was performed uneventfully. Postoperative Spo2 values ranged 82%–89%. Further investigation into the family tree revealed a 5-yr-old brother with a room air Spo2 value of 76%, a 27-yr-old father with room air Spo2 of 61%–62% and a paternal grandfather with room air Spo2 of 80%–82%. Results of hemoglobin electrophoresis showed an abnormal hemoglobin variant, known as hemoglobin Cheverly (Table 1). In summary, a pulse oximeter is not an accurate monitor for patients with unstable hemoglobin Cheverly and possibly other hemoglobinopathies (2,3).

Venous Air Embolism during Surgical Manipulation of a Femoral Bone Cyst

Venous air embolism has been reported as a complication of many types of surgery. We report here an unusual case of air embolism in a child, occuring as a result of surgical manipulations of a femoral bone cyst

Butorphanol and promethazine as pre-anaesthetic medication.

An open evaluation of a combination of butorphanol (1 or 2 mg), promethazine (25 or 50 mg) and atropine (0.5 mg) in 109 adult consenting patients was carried out to determine their safety and efficacy for pre-anaesthetic medication. All patients were kept under direct surveillance from before intramuscular medication until they were in satisfactory condition post-operatively for discharge from the recovery room. The medications employed did not disturb the blood pressure, pulse rate or respiration rate in any of the patients. None complained of nausea or dizziness while only one was slightly excited. Sedation was rated as satisfactory in 97 per cent, and 90 per cent were free of apprehension. In addition, global evaluation of the premedication by the investigator was rated good to excellent in 99 per cent of the patients. On the basis of these observations, the combination of butorphanol with promethazine and atropine appears safe and useful for pre-anaesthetic medication.