scholarly journals Effects of Standard and Sustained-release Buprenorphine on the Minimum Alveolar Concentration of Isoflurane in C57BL/6 Mice

2020 ◽  
Vol 59 (3) ◽  
pp. 298-304
Author(s):  
Philip C LaTourette ◽  
Emily M David ◽  
Cholawat Pacharinsak ◽  
Katechan Jampachaisri ◽  
Jennifer C Smith ◽  
...  
Keyword(s):  
Sustained Release ◽  
Minimum Alveolar Concentration ◽  
Noxious Stimulus ◽  
Male And Female ◽  
Isoflurane Concentration ◽  
Crystalloid Fluid ◽  
Fluid Control ◽  
Control Injection

Both standard and sustained-release injectable formulations of buprenorphine (Bup and BupSR, respectively) are used as preemptive analgesics, potentially affecting gas anesthetic requirements. This study tested the effects of Bup and BupSR on isoflurane requirements and confirmed that buprenorphine could reduce isoflurane requirements during a laparotomy in mice. We hypothesized that both Bup and BupSR would significantly decrease the required minimum alveolar concentration (MAC) of isoflurane. C57BL/6 mice received either isotonic crystalloid fluid (control), Bup (0.1 mg/kg), or BupSR (1.2 mg/kg) subcutaneously 10 min prior to the induction of anesthesia. Each anesthetized mouse was tested at 2 isoflurane concentrations. A 300-g noxious stimulus was applied at each isoflurane concentration, alternating between hindfeet. In addition, a subset of mice underwent terminal laparotomy or 60 min of anesthesia after injection with Bup, BupSR, or saline to ensure an appropriate surgical plane of anesthesia. Mice were maintained at the lowest isoflurane concentration that resulted in 100% of mice at a surgical plane from the aforementioned MAC experiments (control, 2.0%; Bup and BupSR, 1.7%). Analysis showed that both Bup and BupSR significantly decreased isoflurane requirements by 25.5% and 14.4%, respectively. The isoflurane MAC for the control injection was 1.80% ± 0.09%; whereas Bup and BupSR decreased MAC to 1.34% ± 0.08% and 1.54% ± 0.09%, respectively. Sex was not a significantly different between the injection groups during MAC determination. All of the mice that underwent surgery achieved a surgical plane of anesthesia on the prescribed regimen and recovered normally after discontinuation of isoflurane. Lastly, heart and respiratory rates did not differ between mice that underwent surgery and those that were anesthetized only. Bup and BupSR are MAC-sparing in male and female C57BL/6 mice and can be used for effective multimodal anesthesia.

Increasing Isoflurane from 0.9 to 1.1 Minimum Alveolar Concentration Minimally Affects Dorsal Horn Cell Responses to Noxious Stimulation 

1999 ◽  
Vol 90 (1) ◽  
pp. 208-214 ◽  
Author(s):  
Joseph F. Antognini ◽  
Earl Carstens
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Minimum Alveolar Concentration ◽  
Neuronal Response ◽  
Spinal Cord Dorsal Horn ◽  
Noxious Stimulus ◽  
Lumbar Spinal Cord ◽  
Noxious Stimulation ◽  
Neuronal Responses ◽  
Cell Responses

Background The spinal cord appears to be the site at which isoflurane suppresses movement that occurs in response to a noxious stimulus. In an attempt to localize its site of suppressant action, the authors determined the effect of isoflurane on dorsal horn neuronal responses to supramaximal noxious stimulation at end-tidal concentrations that just permitted and just prevented movement. Methods Rats (n = 14) were anesthetized with isoflurane, and after lumbar laminectomy, the minimum alveolar concentration (MAC) for each rat was determined using a supramaximal mechanical stimulus. In these same rats, after extracellular microelectrode placement in the lumbar spinal cord, dorsal horn neuronal responses to the supramaximal stimulus were determined at the concentrations of isoflurane that bracketed each rat's MAC (0.1% higher and lower than MAC). The MAC of isoflurane was then re-determined. Results Dorsal horn neuronal response was 1,757+/-892 impulses/min at 0.9 MAC and 1,508+/-988 impulses/min at 1.1 MAC, a 14% decrease (P < 0.05). Cell responses varied, with some cells increasing their response at the higher concentration of isoflurane. The MAC of isoflurane was 1.38+/-0.2% before and 1.34+/-0.2% after determination of dorsal horn neuronal responses. Conclusions Isoflurane, at concentrations that bracket MAC, has a variable and minimal depressant effect on dorsal horn cell responses to noxious mechanical stimulation. These data suggest that the major action of isoflurane to suppress movement evoked by a noxious stimulus might occur primarily at a site other than the dorsal horn.

The Effect of Hypothermia on Isoflurane MAC in Children

2001 ◽  
Vol 94 (3) ◽  
pp. 429-432 ◽  
Author(s):  
Mingzheng Liu ◽  
Xiaoqin Hu ◽  
Jin Liu
Keyword(s):  
Minimum Alveolar Concentration ◽  
Heart Diseases ◽  
Skin Incision ◽  
Open Heart ◽  
Isoflurane Concentration ◽  
Inhaled Anesthetics ◽  
End Tidal

Background Hypothermia has been shown to decrease the requirement for inhaled anesthetics in animals, but information in humans is limited. Methods Thirty-three unpremedicated children with congenital left-to-right shunt heart diseases undergoing open heart surgeries were assigned to one of three groups, with nasopharyngeal temperatures at the time of skin incision of 37, 34, or 31 degrees C. Anesthesia was induced and maintained with isoflurane in oxygen. End-tidal isoflurane concentration and nasopharyngeal temperature were kept at stable levels for at least 15 min before the skin incision. Isoflurane minimum alveolar concentration was determined by using the Dixon up-and-down approach. Results Isoflurane minimum alveolar concentration values were 1.69 +/- 0.14%, 1.47 +/- 0.10%, and 1.22 +/- 0.15% (mean +/- SD) at 37, 34, and 31 degrees C, respectively. Conclusions Hypothermia decreases the isoflurane requirement in children by 5.1 degrees C.

Comparison of Minimum Alveolar Concentration between Intravenous Isoflurane Lipid Emulsion and Inhaled Isoflurane in Dogs

2006 ◽  
Vol 104 (3) ◽  
pp. 482-487 ◽  
Author(s):  
Xiao-Lin Yang ◽  
Han-Xiang Ma ◽  
Zong-Bin Yang ◽  
Ai-Jie Liu ◽  
Nan-Fu Luo ◽  
...  
Keyword(s):  
Intravenous Injection ◽  
Lipid Emulsion ◽  
Time Course ◽  
Minimum Alveolar Concentration ◽  
Intravenous Anesthesia ◽  
Inhalation Anesthesia ◽  
Isoflurane Concentration ◽  
Arterial Blood ◽  
Anesthesia Group ◽  
End Tidal

Background As in inhaled isoflurane anesthesia, when isoflurane lipid emulsion (ILE; 8%, vol/vol) is intravenously administered, the primary elimination route is through the lungs. This study was designed to determine the minimum alveolar concentration (MAC) and the time course of washout of isoflurane for intravenously infused ILE by monitoring end-tidal isoflurane concentration. Methods Twelve healthy adult mongrel dogs were assigned randomly to an intravenous anesthesia group with 8% ILE or to an inhalation anesthesia group with isoflurane vapor. An up-and-down method and stimulation of tail clamping were used to determine MAC of 8% ILE by intravenous injection in the intravenous anesthesia group and MAC by the inhaled approach in the inhalation anesthesia group, respectively. Isoflurane concentration and partial pressure in end-tidal gas, femoral arterial blood, and jugular venous blood were measured simultaneously just before each tail clamping and during washout. Results The induction time in the intravenous anesthesia group (105 +/- 24 s) was shorter than that in the inhalation anesthesia group (378 +/- 102 s; P < 0.01). MAC of 8% ILE by intravenous injection (1.12 +/- 0.18%) was significantly less than MAC by the inhaled approach (1.38 +/- 0.16%; P < 0.05). No significant difference was found between the two groups in the time course of washout of isoflurane. Conclusion The MAC of intravenous anesthesia with 8% ILE was less than that of inhalation anesthesia with isoflurane vapor in dogs.

Reduction of isoflurane MAC with buprenorphine and morphine in rats

2000 ◽  
Vol 34 (3) ◽  
pp. 252-259 ◽  
Author(s):  
A. B. Criado ◽  
I. A. Gómez de Segura ◽  
F. J. Tendillo ◽  
F. Marsico
Keyword(s):  
Respiratory Depression ◽  
Postoperative Period ◽  
Wistar Rats ◽  
Minimum Alveolar Concentration ◽  
Noxious Stimulus ◽  
Before And After ◽  
Dose Dependent Fashion ◽  
Male Wistar Rats ◽  
Sparing Effect ◽  
Dose Dependent

Preoperative analgesics are being increasingly used to provide analgesia in the intraoperative and postoperative period. Opioids reduce anaesthetic requirements, although the effect varies with the different drug and species. The aim of this work was to determine whether buprenorphine reduces the minimum alveolar concentration (MAC) of isoflurane in a dose-related fashion, and whether this effect is similar to morphine when clinical doses of both drugs are used in the rat. Thirty-six male Wistar rats were anaesthetized with isoflurane, and MAC was determined before and after the administration of either buprenorphine or morphine. MAC of isoflurane was determined from alveolar gas samples when a standard noxious stimulus, in the form of a tail clamp, was applied. The duration and degree of reduction of the MAC of isoflurane were recorded. Basic cardiovascular and respiratory measurements were also recorded. Buprenorphine (10, 30 and 100 μg/kg) and morphine (1, 3 and 10 mg/kg) reduced in a dose-dependent fashion the MAC of isoflurane by 15%, 30% and 50%, respectively. Buprenorphine resulted in less cardiovascular and respiratory depression and had a longer-lasting action than morphine. In conclusion, buprenorphine has a dose-related isoflurane sparing effect in the rat similar to that caused by morphine at clinical doses of both drugs.

scholarly journals Minimum alveolar concentration of isoflurane in dogs administered two morphine doses

2017 ◽  
Vol 47 (11) ◽  
Author(s):  
Karina Coelho ◽  
Eduardo Raposo Monteiro ◽  
Thais Feres Bressan ◽  
Betânia Souza Monteiro ◽  
Daniela Campagnol ◽  
...  
Keyword(s):  
Minimum Alveolar Concentration ◽  
Subcutaneous Tissue ◽  
Skin Incision ◽  
Noxious Stimulus ◽  
Tissue Dissection

ABSTRACT: This study aimed to evaluate the effects of intramuscular 0.5mg kg-1 (MOR0.5) and 1.0mg kg-1 (MOR1.0) morphine premedication on the minimum alveolar concentration of isoflurane (ISOMAC) in dogs. Eighteen client-owned female dogs were scheduled for elective ovariohysterectomy. Dogs received intramuscular MOR0.5 or MOR1.0 as premedication and propofol IV for induction of anesthesia. Isoflurane was delivered for maintenance of anesthesia and dogs were maintained under normocapnia and normothermia. Determinations of the ISOMAC were conducted by use of the “up-and-down” method. Noxious stimulus (placement of Backhaus towel clamps, a midline skin incision and subcutaneous tissue dissection) was delivered approximately 50 minutes after premedication with MOR0.5 or MOR1.0. The calculated ISOMAC was 0.98±0.15% in MOR0.5 and 0.80±0.08% in MOR1.0. The ISOMAC was significantly lower in MOR1.0 compared with MOR0.5 (P=0.010). Results of this study suggested that intramuscular premedication with morphine 0.5 and 1.0mg kg-1 decreases the ISOMAC in a dose-related manner in dogs.

Inhaled Furosemide Inhibits Behavioral Response to Airway Occlusion in Anesthetized Cats

2001 ◽  
Vol 95 (5) ◽  
pp. 1234-1237 ◽  
Author(s):  
Shino Nehashi ◽  
Takashi Nishino ◽  
Tohru Ide
Keyword(s):  
Behavioral Response ◽  
Motor Response ◽  
Positive Response ◽  
Minimum Alveolar Concentration ◽  
Escape Behavior ◽  
Noxious Stimulus ◽  
Airway Occlusion ◽  
Anesthetic Concentration ◽  
End Tidal ◽  
Spontaneously Breathing

Background A recent study showed that inhaled furosemide greatly improves experimentally induced dyspnea in humans. The objective of the current study is to test the hypothesis that inhaled furosemide suppresses the behavioral response to airway occlusion without changing the behavioral response to a somatic noxious stimulus in anesthetized animals. Methods In 10 spontaneously breathing cats anesthetized with isoflurane, anesthetic ED(50) was determined by measuring an end-tidal anesthetic concentration while observing escape behavior. The monitored behavior consisted of purposeful movement of the head and forearm after endotracheal tube occlusion. The duration from the start of airway occlusion to the onset of the positive response (DOCCL) was measured at the highest concentration of isoflurane permitting the positive motor response to airway occlusion before pretreatment. ED(50) values (minimum alveolar concentration) for the suppression of a somatic motor response to a noxious stimulus induced by toe pinch (toe-pinch ED(50)) were also determined. Then, the effects of inhaled furosemide or vehicle on the ED(50) for the suppression of the behavioral response to airway occlusion, DOCCL, and toe-pinch ED(50) were evaluated in a randomized, cross-over design. Results The ED(50) for the suppression of the behavioral response to airway occlusion significantly decreased (P < 0.01) and DOCCL was significantly prolonged (P < 0.01) after furosemide inhalation, whereas vehicle inhalation did not change these measurements. The decrease in ED(50) for the suppression of the behavioral response to airway occlusion after furosemide inhalation lasted 3 h. Furosemide inhalation did not affect the toe-pinch ED(50). Conclusion Inhaled furosemide suppressed the behavioral response to airway occlusion in anesthetized animals without affecting the response to somatic noxious stimulus. The authors' animal model of respiratory distress may be applicable to the study of dyspnea in regard to its mechanism and treatment.

scholarly journals Minimum alveolar concentration of isoflurane in dogs administered a single intramuscular injection of racemic or S (+)-ketamine after premedication with acepromazine-morphine

2017 ◽  
Vol 47 (1) ◽  
Author(s):  
Thais Feres Bressan ◽  
Eduardo Raposo Monteiro ◽  
Karina Coelho ◽  
Betânia Souza Monteiro ◽  
Daniela Campagnol
Keyword(s):  
Single Dose ◽  
Intramuscular Injection ◽  
Minimum Alveolar Concentration ◽  
Noxious Stimulus ◽  
Anesthetic Induction ◽  
Single Intramuscular Injection ◽  
Sparing Effect

ABSTRACT: The present study evaluated the minimum alveolar concentration of isoflurane (ISOMAC) in twenty three dogs premedicated with acepromazine (0.02mgkg-1) and morphine (0.5mgkg-1) and administered racemic (RK) or S(+)-ketamine (SK). Dogs randomly received a single dose (3mgkg-1, IM) of either RK or SK 15minutes after anesthetic induction with propofol. The ISOMAC was determined by the up-and-down method. Approximately 20 minutes after administration of RK or SK, a surgical noxious stimulus was applied and the response evaluated. The ISOMAC was 0.50±0.01% in the RK group (n=10) and 0.31±0.04% in the SK group (n=13). The ISOMAC was 38% lower in the SK group compared to the RK group. Results of the present study revealed that in dogs premedicated with acepromazine and morphine, IM administration of 3mgkg-1 ketamine approximately 20 minutes before the noxious stimulus produced clinically important reduction in the ISOMAC and the MAC-sparing effect was significantly greater with SK compared to RK.

Organ index of immunological and anti-tumor effect of intratumor injection of penicillin sodium combined with chemotherapy drug for tumor-bearing mice.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e16134-e16134
Author(s):  
Qiang Fu ◽  
Yan Han ◽  
Bian Li ◽  
Jian Zhang ◽  
Dong Chen ◽  
...  
Keyword(s):  
Sustained Release ◽  
Tumor Growth ◽  
Survival Time ◽  
Skin Test ◽  
Intratumoral Injection ◽  
Tumor Formation ◽  
Inhibition Rate ◽  
Male And Female ◽  
Tumor Bearing ◽  
Organ Index

e16134 Background: To observe the antitumor mechanism of penicillin combined with chemotherapy drugs in tumor-bearing mice. Methods: The H22 experimental tumors were randomly divided into groups when the longest diameter of the tumor reached about 4 to 7 mm. First and the second administration was performed every 7 days. Perform a skin test and observe the local response. There were 22 mice in each group, male and female. The No. 1 to No. 3 of each group of male and female are used for pharmacodynamic experiments and executed by cervical dislocation on the 13th day. The tumor tissue is removed, weighed, and the tumor growth inhibition rate is calculated. Thymus and spleen, calculate the thymus and spleen coefficients. The male and female Nos. 4 to 8 of each group was used for survival experiments. The death time of the mice was observed and recorded. And 9 to 11 mice from the male and female mice in each dose group of penicillin were taken for skin test, and the skin test response was recorded; the 4th day after the second administration (the 12th day of the experiment) the 9th to 11th of each group No. is used for the tumor formation time experiment of the contralateral tumor. The tumor formation time of the mice is observed and recorded. Results: (1) Comparison with body weight. Sustained-release chemotherapeutic agents of penicillin sustained-release medicines by hydrogen peroxide can cause less damage to mice. (2) Compared with tumor volume and tumor inhibition rate, the compound group (I-Ⅵ) could significantly inhibit tumor growth in mice after intratumoral injection, but penicillin and DNP had no obvious tumor inhibition after intratumoral injection. (3) The comparison of thymus coefficients shows that the adjuvant can obviously prevent the damage to the thymus caused by the drug and has a certain protective effect on the thymus which is very important organ for immune systems. Comparison of survival time, the survival rate and average survival time of the compound Ⅱ group were higher than those of other compound groups. Conclusions: Based on the efficacy and survival results, this intratumoral injection with penicillin could increase organ index for spleen and thymus and indicated it could increase immunological response to against whole body cancer cell.

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