Brazilian Journal of Anesthesiology
https://app.periodikos.com.br/journal/rba/article/doi/10.1590/S0034-70942003000100004
Brazilian Journal of Anesthesiology
Scientific Article

Avaliação da anestesia com baixo fluxo de gases, comparando ventilação com pressão controlada à ventilação com tempo controlado - pressão limitada e fluxo constante de gases: modelo experimental em coelhos

Evaluation of low flow anesthesia, comparing pressure-controlled ventilation to time-cycled pressure-limited continuous flow ventilation: experimental model in rabbits

Eliana Bonetti; Denise Tabacchi Fantoni; José Otávio Costa Auler Júnior

http://dx.doi.org/10.1590/S0034-70942003000100004 Braz J Anesthesiol, vol.53, n1, p.25-38, 2003
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Resumo

JUSTIFICATIVA E OBJETIVOS: Embora sejam amplamente conhecidas as vantagens que envolvem sistemas de anestesia com reinalação e baixo fluxo, estes ainda são pouco empregados em animais de pequeno porte e em pediatria. O modelo experimental deste estudo foi delineado, procurando-se avaliar a viabilidade do sistema com reinalação e fluxo de gases entre 500 e 1.000 ml.min-1 em animais de pequeno porte, bem como comparar a ventilação nos modos tempo controlado - pressão limitada e fluxo constante de gases, com a pressão controlada (PCV), em um novo equipamento desenvolvido para anestesia. MÉTODO: Dezesseis coelhos (fêmeas) foram distribuídos aleatoriamente em dois grupos (GI e GII), anestesiados com halotano, e submetidos à ventilação controlada mecânica. Em GI, permitiam-se ajustes nos parâmetros ventilatórios do ventilador (pressão de pico inspiratório, freqüência respiratória e tempo inspiratório), de forma a manter normocapnia, volume corrente entre 6 e 8 ml.kg-1, e pH sangüíneo arterial entre 7,35 e 7,45. Em GII, os ajustes eram realizados somente no momento controle. RESULTADOS: Verificou-se reinalação de dióxido de carbono em ambos os grupos ao se avaliar o sistema com reinalação, independente do modo de ventilação. O pH sangüíneo arterial manteve-se dentro dos parâmetros fisiológicos no grupo GI, e no GII verificou-se acidose respiratória ao se avaliar o sistema com reinalação durante a ventilação com pressão controlada. CONCLUSÕES: Com os resultados obtidos conclui-se que este sistema circular, em fluxos entre 500 e 1.000 ml.min-1, é uma alternativa em anestesia em pacientes de baixo peso, desde que a monitorização necessária seja feita. A eficiência da ventilação dependeu primariamente dos parâmetros ventilatórios ajustados, da complacência e resistência das vias aéreas, e nem tanto do modo de ventilação escolhido.

Palavras-chave

ANIMAL, EQUIPAMENTOS, EQUIPAMENTOS, EQUIPAMENTOS, VENTILAÇÃO

Abstract

BACKGROUND AND OBJECTIVES: Despite the well-known advantages of rebreathing systems and low flow anesthesia, they are seldom used in small animals and pediatric anesthesia. The experimental model of this study was designed to evaluate a rebreathing system with flows between 500 to 1,000 ml.min-1 in small animals, in addition to comparing time-controlled pressure-limited and constant gas flow ventilation to pressure-controlled ventilation in a new anesthesia machine. METHODS: Sixteen female rabbits were randomly allocated in two groups (GI and GII), anesthetized with halothane and submitted to mechanically-controlled ventilation. Adjustments in ventilatory parameters were allowed in GI (peak inspiratory pressure, respiratory rate and inspiratory time) to maintain normocapnia, tidal volume between 6 and 8 ml.kg-1 and arterial pH between 7.35 and 7.45. Adjustments in GII were only allowed at control moment. RESULTS: Carbon dioxide rebreathing was observed in both groups when rebreathing systems were evaluated, regardless of the ventilation mode. Arterial pH was maintained within physiologic parameters in GI, and respiratory acidosis was observed in GII when the rebreathing system was evaluated during pressure-controlled ventilation. CONCLUSIONS: According to our results, a circle system with flows between 500 and 1,000 ml.min-1 may be an alternative for low weight patients anesthesia, provided necessary monitoring is performed. Ventilation efficiency was primarily a function of adjusted ventilatory parameters, of airways compliance and resistance and not so much of the ventilation mode.

Keywords

ANIMAL, EQUIPMENTS, EQUIPMENTS, EQUIPMENTS, VENTILATION

References

Frölich D, Schwall B, Funk W. Laryngeal mask airway and uncuffed tracheal tubes are equally effective for low flow or closed system anaesthesia in children. Br J Anaesth. 1997;79:289-292.

Henriksson BA, Sundling J, Hellman A. The effect of a heat and moisture exchanger on humidity in a low-flow anaesthesia system. Anaesthesia. 1997;52:144-149.

Perkins R, Meakin G. Economics of low-flow anaesthesia in children. Anaesthesia. 1996;51:1089-1092.

Baxter AD. Low flow and minimal flow inhalational anaesthesia. Can J Anaesth. 1997;44:643-653.

Baum JA. Low Flow Anaesthesia: The Theory and Practice of Low Flow, Minimal Flow and Closed System Anaesthesia. 1996:132-150.

Amato MBP, Barbas CSV, Medeiros DM. Effect of a protective - ventilation strategy on mortality in the acute respiratory distress syndrome. N Eng J Med. 1998;338:347-354.

Hooper J. Advances in mechanical ventilation. Can J Anaesth. 1998;45:R149-R154.

Slutsky AS. Mechanical ventilation (ACCP Consensus Conference). Chest. 1993;104:1833-1859.

Barbas CSV, Rothman A, Amato MBP. Técnicas de Assistência Ventilatória. Condutas no Paciente Grave. 1995:312-346.

Marik PE, Krikorian J. Pressure-controlled ventilation in ARDS: a practical approach. Chest. 1997;112:1102-1106.

Dreyfuss D, Saumon G. Role of tidal volume, FRC, and end-inspiratory volume in the development of pulmonary edema following mechanical ventilation. Am Rev Respir Dis. 1993;148:1194-1203.

Tobin MJ. Principles and Practice of Mechanical Ventilation. 1994;371:512-513.

Meade MO. An evidence-based approach to pressure-and volume-limited ventilation strategies. Crit Care Clin. 1998;14:373-385.

Auler Jr JOC, Pereira JCD. Efeitos Pulmonares da Ventilação Mecânica. Gomide do Amaral RV: Assistência Ventilatória Mecânica. 1995:121-128.

Davis K, Branson RD, Campbell RS. Comparison of volume control and pressure control ventilation: is flow waveform the difference?. J Trauma. 1996;41:808-814.

Adriani J, Griggs T. Rebreathing in pediatric anesthesia: recommendations and descriptions of improvements in apparatus. Anesthesiology. 1953;14:337-347.

Stephen CR, Slater HM. Agents and techniques employed in pediatric anesthesia. Anesth Analg. 1950;29:254-262.

Ver Steeg J, Stevens WC. A comparison of respiratory effort of infants anesthetized with several adult and pediatric systems. Anesthesiology. 1966;27:229.

Graff TD, Holzman RS, Benson DW. Acid-base balance in infants during halothane anesthesia with the use of an adult circle-absorption system. Anesth Analg. 1964;43:583-589.

Hughes DG. Paediatric Anaesthetic Apparatus. Handbook of Paediatric Anaesthesia. 1996:43-61.

Hodgson DS. The Case for Nonrebreathing Circuits for Very Small Animals. Opinions in Small Animal Anesthesia: The Veterinary Clinics of North America. 1992;22:397-399.

Dunlop CI. The Case for Rebreathing Circuits for Very Small Animals. Opinions in Small Animal Anesthesia: The Veterinary Clinics of North America. 1992;22:400-403.

Badgwell JM, Swan J, Foster AC. Volume-controlled ventilation is made possible in infants by using compliant breathing circuits with large compression volume. Ped Anesthesia. 1996;82:719-723.

Hernandez LA, Peevy KJ, Moise AA. Chest wall restriction limits high airway pressure-induced lung injury in young rabbits. J Appl Physiol. 1989;66:2364-2368.

Perez Fontán JJ, Heldt GP, Gregory GA. Dynamics of respiration during rapid rate mechanical ventilation in anesthetized and paralyzed rabbits. Ped Research. 1986;20:750-755.

Lachmann B, Grossmann G, Nilsson R. Lung mechanics during spontaneous ventilation in premature and fullterm rabbit neonates. Respir Physiol. 1979;38:283-302.

Crossfill ML, Widdicombe JG. Physical characteristics of the chest and lungs and the work of breathing in different mammalian species. Physiology. 1961;158:1-14.

Wyatt JD, Scott RAW, Richardson ME. The effects of prolonged ketamine - xylazine intravenous infusion on arterial blood pressure, heart and respiratory rates, rectal temperature and reflexes in the rabbits. Lab An Sci. 1989;39:411-416.

Baker AB. Low flow and closed circuits. Anaesth Intensive Care. 1994;22:341-142.

Lang SM, Eglen RM, Henry AC. Acetylpromazine administration: its effects on canine haematology. Vet Rec. 1979;105:397-398.

Shapiro BA, Harrison RA, Walton JR. Aplicações Clínicas dos Gases Sangüíneos. 1980:282.

Baum JA. Low-flow anaesthesia. Eur J Anaesth. 1996;13:432-435.

Silva ED, Quinto D. Controle da Hipotermia Acidental. Atualização em Anestesiologia. 1998:111-127.

Sessler DI. Conseqüências e Tratamento da Hipotermia Perioperatória. Clínicas de Anestesiologia da América do Norte: Regulação da Temperatura durante a Anestesia. 1994:417-449.

Motoyama EK, Davis PJ Smith's. Anestesia Pediátrica. 1991:217-256.

Miyoshi MH. Síndrome do Desconforto Respiratório do Recém-Nascido. Ventilação Pulmonar Mecânica em Pediatria. 1993:263-272.

Romand JA, Suter PM. Dynamic hyperinflation and intrinsic PEEP during mechanical ventilation. Eur J Anaesth. 1994;11:25-28.

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