Anesthesia case of the month. Inadvertent endobronchial intubation resulted in hypoxemia.
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Biomedical subjects
Publications and source records attributed to C J McGrath.
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Basal-cell naevus syndrome is characterized by multiple odontogenic keratocysts as well as skeletal, ophthalmologic and neurologic features. It is important that the dental practitioner be aware of this syndrome as it has important ramifications for the developing dentition. A case of Basal-cell naevus syndrome is presented along with a review of the literature regarding the management of this disorder. An argument for conservative surgical management of this syndrome is made.
Condylar fractures are sustained commonly by children and are readily diagnosed in the main. Three case histories serve to illustrate the intricate anatomy of the area and how damage to it can produce unusual signs and symptoms which can mislead the unwary. Supplemental images, in particular coronal CTs, can be instrumental in arriving at the correct diagnosis and treatment.
A method of placing two endosteal implants with simultaneous bone grafting to the anterior mandible is described. This technique is simple to use, has minimal morbidity, and has produced good preliminary results. Retrospectively, 18 patients with a total of 36 implants were reviewed. An implant success rate of 91.6% was seen at a mean follow-up time of 17 months after loading with an implant-supported, soft-tissue-borne overdenture.
We evaluated combinations of telazol, ketamine, and xylazine (TKX), telazol and xylazine (TX), telazol, xylazine, and xylazine (T2X), and ketamine and xylazine (KX) for chemical restraint and anesthesia induction in swine. Forty healthy mixed-breed pigs were randomly assigned to the four treatment groups with 10 pigs in each group. For TKX, TX, and T2X combinations, anesthetics were premixed by adding xylazine and ketamine, sterile water and xylazine, or xylazine alone directly into the telazol vial. For KX, anesthetic agents were drawn up separately, then mixed in the same syringe immediately before injection. All anesthetics were given as a single intramuscular injection. All four anesthetic combinations induced a rapid onset of sternal recumbency within 1.55 +/- 0.5 min and lateral recumbency within 2.27 +/- 0.6 min in pigs after intramuscular injection. There was no significant difference among treatments in these regards. The T2X combination induced a significantly longer duration of analgesia than did either TKX, TX, or KX. The T2X combination also induced a significantly longer duration of tolerance for endotracheal intubation and duration of lateral recumbency. Heart and respiratory rates were not significantly different among the four treatment groups. Vomiting was not observed in any of the treated pigs throughout the procedure. Recovery quality and duration from time of drug administration to recovery of pig walking unassisted were similar in three treatment groups but was shorter in KX-treated pigs. We concluded that all four anesthetic combinations were suitable for chemical restraint but that only TKX, TX, and T2X were suitable for anesthesia induction in pigs.(ABSTRACT TRUNCATED AT 250 WORDS)
We compared the ability of 2 alpha 2-adrenergic receptor antagonists, atipamezole and yohimbine, to reverse medetomidine-induced CNS depression and cardiorespiratory changes in lambs. Twenty lambs (7.8 +/- 2.6 kg) were randomly allotted to 4 treatment groups (n = 5). Each lamb was given medetomidine (30 micrograms/kg of body weight, i.v.), followed in 15 minutes by i.v. administration of atipamezole (30 or 60 micrograms/kg), yohimbine (1 mg/kg), or 0.9% NaCl (saline) solution. Medetomidine caused lateral recumbency in 1 to 2 minutes in all treated lambs. Medetomidine significantly (P < 0.05) decreased heart rate at 5 and 10 minutes after its administration. Heart rate remained above 120 beats/min, and severe bradycardia (< or = 70 beats/min) and other arrhythmias did not occur throughout the study. Medetomidine also induced tachypnea in all treated lambs. The tachypnea was abolished by atipamezole and yohimbine, but not by saline solution administration. The medetomidine-induced tachypnea did not significantly affect arterial pH and PaCO2. Arterial oxygen tension was within acceptable range (PaO2 = 71 to 62 mm of Hg), but was lower than expected. Administration of atipamezole, yohimbine, or saline solution did not change PaO2 significantly. Lambs treated with 30 or 60 micrograms of atipamezole/kg were able to walk unassisted in 2.4 +/- 0.4 and 2.3 +/- 0.7 minutes, respectively, whereas yohimbine- and saline-treated lambs did not walk unassisted until 15.6 +/- 2.7 and 73.0 +/- 6.8 minutes later, respectively. Results of this study indicated that medetomidine is a potent CNS depressant in lambs.(ABSTRACT TRUNCATED AT 250 WORDS)
Pediatric neuro-AIDS may be the first clinical manifestation of HIV infection in children born to HIV-infected mothers. As part of the neurodevelopmental examination of children, the Clinical Adaptive Test/Clinical Linguistic and Auditory Milestone Scale (CAT/CLAMS) was investigated as a tool for pediatricians to use to monitor the development of children at risk for HIV infection. The CAT/CLAMS was found to detect neurodevelopmental differences between HIV-infected and uninfected children at 12 and 18 months of age. Good correlations were found between the CAT/CLAMS and concurrently administered Bayley Scales of Infant Development. These findings suggest that the CAT/CLAMS should be considered as a part of the neurodevelopmental examination of children at risk for pediatric neuro-AIDS.
Cardiopulmonary consequences of IV administered glycopyrrolate (0.01 mg/kg of body weight), followed in 11 +/- 2 minutes by butorphanol (0.2 mg/kg) and xylazine (0.5 mg/kg), were evaluated in 6 dogs, with and without nasal administration of oxygen (100 ml/kg/min). Glycopyrrolate caused significant (P < 0.05) increases in heart rate and cardiac index and significant (P < 0.05) decreases in stroke index. Subsequent administration of butorphanol and xylazine was associated with significant (P < 0.05) increases in systemic vascular resistance, mean arterial blood pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, PaCO2, venous admixture, oxygen extraction ratio, and hemoglobin concentration. It caused significant (P < 0.05) decreases in cardiac index, stroke index, breathing rate, minute volume index, oxygen delivery, and oxygen consumption. Mean arterial blood pressure, pulmonary vascular resistance, tidal volume index, and minute volume index were significantly (P < 0.05) higher when dogs were breathing room air. The arterial and venous PO2 and PCO2, and venous oxygen content were significantly (P < 0.05) higher, and the arterial and venous pH, and oxygen consumption were significantly (P < 0.05) lower when oxygen was administered. Pulsus alternans and S-T segment depression were observed in dogs of both groups. Ventricular premature contractions were observed in 1 dog breathing room air. All dogs were intubated briefly 15 minutes after administration of butorphanol and xylazine. Time to first spontaneous movement was 45 minutes. All dogs remained in lateral recumbency without physical restraint for 60 minutes.
Cardiorespiratory effects of an IV administered bolus of ketamine (7.5 mg/kg of body weight) and midazolam (0.375 mg/kg) followed by IV infusion of ketamine (200 micrograms/kg/min) and midazolam (10 micrograms/kg/min) for 60 minutes was determined in 6 dogs. Ketamine-midazolam combination was administered to dogs on 3 occasions to determine effects of prior administration of IV administered saline solution (1 ml), butorphanol (0.2 mg/kg), or oxymorphone (0.1 mg/kg). The infusion rate of ketamine and midazolam was decreased by 25% for anesthetic maintenance after opioid administration. There were no significant differences in cardiorespiratory variables after saline solution or butorphanol administration; however, oxymorphone caused significant (P < 0.05) increases in mean arterial blood pressure, systemic vascular resistance, and breathing rate. Bolus administration of ketamine-midazolam combination after saline solution caused significant (P < 0.05) increases in heart rate, mean arterial blood pressure, cardiac index, mean pulmonary blood pressure, venous admixture, and significant decreases in stroke index, pulmonary capillary wedge pressure, arterial and mixed venous oxygen tension, arterial oxygen content, and alveolar-arterial oxygen gradient. Opioid administration was associated with significantly (P < 0.05) lower values than was saline administration for heart rate, mean arterial blood pressure, and arterial and mixed venous pH and with higher values for stroke index, pulmonary capillary wedge pressure, and arterial and mixed venous carbon dioxide tension. Prior oxymorphone administration resulted in the highest (P < 0.05) values for mean pulmonary blood pressure, venous admixture, and arterial and mixed venous carbon dioxide tension, and the lowest values for arterial oxygen tension, and arterial and mixed venous pH. Each treatment provided otherwise uncomplicated anesthetic induction, maintenance, and recovery.(ABSTRACT TRUNCATED AT 250 WORDS)
The use of Telazol (T, tiletamine and zolazepam, 4.4 mg T/kg) alone, Telazol-ketamine (TK, 4.4 mg T/kg and 2.2 mg K/kg), Telazol-xylazine (TX, 4.4 mg T/kg, 2.2 mg X/kg), and Telazol-ketamine-xylazine (TKX, 4.4 mg T/kg, 2.2 mg K/kg, and 2.2 mg X/kg) as chemical restraint and anesthetic induction combination was compared in pigs. Forty mixed-breed healthy pigs (24.4 +/- 5.6 kg, mean +/- SD) were randomly assigned to the four treatment groups (T, TK, TX, TKX) with 10 pigs in each group. All the anesthetics were premixed by adding sterile water, ketamine, xylazine, or xylazine and ketamine directly into the Telazol vial and given as a single intramuscular injection. All four anesthetic combinations induced a rapid onset of sternal recumbency within 1.76 +/- 1.0 minutes and lateral recumbency within 3.02 +/- 2.2 minutes in pigs after intramuscular injection; there was no significant difference among treatments. The combinations TX and TKX induced analgesia (as evident by a lack of response to needle prick in the middle portion of the pinna and flank regions) duration of 29.0 +/- 11.0 and 36.0 +/- 12.2 minutes, respectively, and ability to tolerate tracheal intubation (as evident by lack of coughing and chewing response to a laryngoscope) for a period of 34.0 +/- 8.4 and 39.0 +/- 9.9 minutes, respectively. The combinations T and TK did not induce analgesia nor conditions suitable for intubation. Duration of lateral recumbency was 29.9 +/- 10, 33.1 +/- 6.9, 52.2 +/- 6.9, and 61.5 +/- 10.7 minutes in T-, TK-, TX-, and TKX-treated pigs, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven atopic dogs underwent intradermal allergy testing with 46 inhalant antigens before and after administration of a tiletamine/zolazepam solution (4 mg/kg of body weight, IV). This anesthetic protocol had no significant effect on the intradermal response caused by histamine, whole flea extract, or various inhalant allergens. Short-acting chemical restraint induced by the drug combination facilitated the intradermal testing procedure.
The purpose of these experiments was to determine if the Ca2+ agonist BAY K 8644 and the Ca2+ antagonist nifedipine alter the mechanical responses of malignant hyperthermia-susceptible (MHS) skeletal muscle to halothane and caffeine. Muscle fiber bundles were dissected from MHS porcine skeletal muscle and exposed to BAY K 8644 (10 microM), nifedipine (1 microM), low-Ca2+ media [Ca2+ replaced by 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid], or diltiazem (30 microM) administered alone and with halothane (3%) or caffeine (0.5-0.8 mM). When administered alone, both halothane and BAY K 8644 evoked a significant change in resting tension (i.e., contracture) of 193.7 +/- 61.0 and 51.9 +/- 21.5 mN/cm2, respectively. When administered in combination, BAY K 8644 had no effect on the magnitude of the halothane contracture (195.2 +/- 58.6 mN/cm2) but reduced its onset time from 306.7 +/- 36.3 to 105.9 +/- 8.9 s. Nifedipine, low Ca2+, and diltiazem significantly reduced the halothane contracture (103.1 +/- 30.3, 123.1 +/- 20.6, and 112.6 +/- 16.2 mN/cm2, respectively) but had no effect on its onset time. In addition, low Ca2+ reduced the magnitude of the BAY K 8644 contracture (8.2 +/- 2.1 mN/cm2). BAY K 8644 also increased contractures induced by low caffeine concentrations (0.5-2.0 mM) but did not alter contractures induced by 4.0 and 8.0 mM caffeine, whereas nifedipine, low Ca2+, and diltiazem had no effect on these contractures. These results suggest that extracellular Ca2+ influx may have some influence on halothane but not on caffeine contractures of MHS skeletal muscle.
Two digital oscillometric human blood pressure measuring devices were modified and evaluated as blood pressure monitors in 12 healthy anesthetized dogs. Direct arterial pressures were measured via cannulation of the dorsal pedal artery and were correlated with indirect measurements through an inflatable cuff placed over the dorsal pedal artery below the hock joint of the contralateral limb. Direct and indirect measurements were compared for systolic, diastolic, and calculated mean arterial pressures. Blood pressure ranges between 215/145 mm of Hg and 65/30 mm of Hg were obtained, using combinations of halothane, phenylephrine, calcium, and IV administered fluids. Machine A was found to be insufficient for clinical application, on the basis of correlation coefficients between direct and indirect pressures of 0.78, 0.65, and 0.74 for systolic, diastolic, and mean arterial pressures, respectively. Higher correlation coefficients between direct and indirect pressures (0.77, 0.87, and 0.87, respectively) were obtained with machine B. The results of the study reported here suggest machine B may be an effective blood pressure monitoring device in anesthetized dogs.
The median effective dose for capture (ED50) and the median lethal dose (LD50) of alpha-chloralose given orally to domestic chickens (Gallus domesticus) were determined by probit analysis to be 45 mg/kg and 300 mg/kg, respectively. The therapeutic index (TI = LD50/ED50) was 6.7. This indicates that alpha-chloralose is only a marginally safe capture agent in domestic species and particularly in field applications involving other wild avian species in which the amount of the drug ingested by an individual bird is not controlled.
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Anesthesia may be required in various species of poultry to facilitate surgery, diagnostics, and research. Preanesthetic evaluation, careful anesthetic management, and proper supportive methods should be employed. Injectable regimens may be useful for some procedures, but inhalation methods are more appropriate for long periods of anesthesia. Intubation of the trachea and maintenance of ventilation are of particular importance in avian species. Monitoring and support should continue until recovery is complete.
The effects of verapamil on the chronotropic response to vagal stimulation in young pigs anesthetized with sodium pentobarbital (30 mg/kg of body weight, intraperitoneally) was evaluated. After bilateral vagotomy, the administration of verapamil (loading dose of 100 micrograms/kg, followed by 2 micrograms/kg/min infusion) resulted in a significant (P less than 0.05) reduction in heart rate (HR) and mean arterial blood pressure. Cardiac frequency responses to vagal stimulation were obtained by stimulating the distal end of the right vagus nerve at selected frequencies (5, 10, 15, and 20 Hz) with supramaximal voltage (10 to 15 V) and constant duration (2 ms). The HR was measured after 15 s at each level of stimulation. The slopes of decrease in HR to the frequency of vagal stimulation were significantly (P less than 0.05) reduced after verapamil as compared with its controls. After atropine (0.5 mg/kg), the vagally induced tachycardia was partially attenuated by verapamil, but was completely eliminated by beta blockade with propranolol (1 mg/kg). These findings indicated that verapamil may influence the parasympathetic control of the heart in young pigs.