RESUMEN
We investigated behavioral symptoms of neuropathic pain, and associated changes in dorsal horn neurons, in a rat model involving loose ligation of lumbar dorsal roots. The L4-L6 dorsal roots were exposed unilaterally and loosely constricted central to the respective ganglia with one (1-ligation) or two (2-ligation) silk 7-O ligatures. In control groups the dorsal roots were exposed but not ligated (sham-operated), or sutures were placed lengthwise between the dorsal roots (suture control). There was a significant reduction in mechanical withdrawal threshold on the operated side in both 1- and 2-ligation groups which began at 3 days, peaked at 2-5 week, and gradually recovered. A delayed threshold reduction was also seen on the non-operated side. Immediately post-surgery there was a significant increase (hypoalgesia) in thermal paw withdrawal latency (Hargreaves test) in 1- and 2-ligation groups on the operated (but not non-operated) side that recovered after 1 week. Significantly less weight was borne by the operated limb 1-5 weeks post-operatively in 1- and 2-ligation groups. The force of hind limb withdrawals elicited by graded noxious heat pulses (38-52 degrees C) was significantly lower 1 week post-surgery on the operated side (1-ligation group) followed by recovery. Withdrawal forces were higher 5-9 week post-surgery on the non-operated side in 1- and 2-ligation groups. We found no evidence of cold allodynia. Neither sham-operated nor suture controls showed any signs of allodynia or hyperalgesia. Following behavioral testing, rats were anesthetized with halothane for single-unit recordings from lumbar wide dynamic range-type (WDR) neurons. At 22 week post-surgery, the mean area of mechanosensitive receptive fields was significantly larger for units on the operated side in 1- and 2-ligation groups compared with those on the non-operated side or with those from sham-operated rats. Mean stimulus-response functions to graded noxious heat pulses (38-52 degrees C, 5 s) were not significantly different between operated and non-operated sides for 1- or 2-ligation groups, or compared with the 22-week sham-operated group. At 5 week post-surgery, the mean area of cutaneous receptive fields, and stimulus-response functions to graded noxious heat, were not significantly different between units recorded on operated versus non-operated sides, or compared with units from 5-week sham-operated rats. Spontaneous unit activity was significantly higher on the operated versus non-operated side in the 2-ligation (22-week) and sham (5-week) groups. Enlarged cutaneous receptive fields of dorsal horn neurons may contribute to mechanical allodynia associated with dorsal root constriction. However, the slow (>5 week) development of receptive field enlargement does not match the rapid development of allodynia. The lack of effect of dorsal root constriction on thermal sensitivity of dorsal horn units ipsilaterally corresponds to the lack of marked thermal hyperalgesia observed behaviorally.
Asunto(s)
Conducta Animal/efectos de los fármacos , Neuralgia/fisiopatología , Neuronas Aferentes/fisiología , Médula Espinal/fisiopatología , Raíces Nerviosas Espinales/fisiopatología , Animales , Electrofisiología , Marcha/fisiología , Miembro Posterior , Calor , Ligadura , Región Lumbosacra , Masculino , Síndromes de Compresión Nerviosa/complicaciones , Síndromes de Compresión Nerviosa/tratamiento farmacológico , Síndromes de Compresión Nerviosa/fisiopatología , Neuralgia/tratamiento farmacológico , Neuralgia/etiología , Neuronas Aferentes/efectos de los fármacos , Estimulación Física , Ratas , Ratas Sprague-Dawley , Reflejo/fisiología , Nervio Ciático/citología , Nervio Ciático/fisiopatología , Médula Espinal/citología , Raíces Nerviosas Espinales/citología , SuturasRESUMEN
Newborn plasma concentrations of maternally administered bupivacaine are often measured, but it is unclear how well they reflect tissue concentrations. Bupivacaine (0.25%) was administered epidurally (0. 12 ml/kg) 10 min prior to labor induction in 6 term-pregnant guinea pigs. Plasma, brain, heart and liver samples were obtained for bupivacaine analysis from newborns (n = 22) after spontaneous delivery. Liver bupivacaine concentrations were 2-3 times greater than those in the plasma, brain, and heart. A similar pattern of tissue concentrations was seen in a smaller number of newborns delivered by cesarean section. Liver bupivacaine concentration decreased with drug-delivery interval in littermates, while heart and brain concentrations showed no relationship with drug-delivery interval. Blood gases of newborns reflected acidosis, which may have influenced tissue drug concentrations. Under conditions of the study, bupivacaine concentrations in heart and brain, potential sites of bupivacaine action, were lower than those observed in a peripheral blood sample.
Asunto(s)
Anestésicos Locales , Animales Recién Nacidos/metabolismo , Bupivacaína/administración & dosificación , Bupivacaína/análisis , Inyecciones Epidurales , Trabajo de Parto , Animales , Química Encefálica , Bupivacaína/farmacocinética , Dióxido de Carbono/administración & dosificación , Cesárea , Parto Obstétrico , Femenino , Feto/metabolismo , Cobayas , Hígado/química , Miocardio/química , EmbarazoRESUMEN
We investigated if carrageenan-induced thermal hyperalgesia and mechanical allodynia are associated with a reduction in threshold and-or enhancement of suprathreshold nocifensive responses, using a method to measure the force of a hind limb wilhdrawal reflex elicited by graded noxious heat stimuli (36-52 degrees C, 5s) delivered by Peltier thermode tethered to the ventral hind paw of conscious rats. Withdrawal reflexes were recorded 2.5 h after intraplantar injection of carrageenan (1 or 0.1%) or saline vehicle in sessions >2 weeks apart: baseline reflexes were assessed the day before. Withdrawal reflex force increased linearly from 42-52 degrees C. Carrageenan 1% significantly enhanced withdrawal reflexes at 40-46 degrees C, reducing the slope and threshold of the stimulus-response function. This was associated with significant reductions in thermal paw withdrawal latency (Hargreaves test: by 50%), mechanical withdrawal threshold (by 82%) and weight bearing on the injected side (by 81%) measured with independent force plates. Smaller reductions in thermal paw withdrawal latency and mechanical withdrawal threshold, and smaller enhancement of withdrawal reflex force, were observed following 0.1% carrageenan. Intraplantar saline was ineffective. This method allows assessment of hyperalgesic changes in stimulus-response coding over a broad range of noxious stimulus intensities.
Asunto(s)
Conducta Animal/efectos de los fármacos , Conducta Animal/fisiología , Carragenina/farmacología , Miembro Posterior/fisiología , Calor/efectos adversos , Hiperalgesia/inducido químicamente , Dolor/inducido químicamente , Reflejo/efectos de los fármacos , Animales , Carragenina/administración & dosificación , Modelos Animales de Enfermedad , Esquema de Medicación , Inyecciones Subcutáneas , Masculino , Contracción Muscular/fisiología , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Reflejo/fisiología , Fenómenos Fisiológicos de la Piel/efectos de los fármacos , Estrés Mecánico , Soporte de Peso/fisiologíaRESUMEN
Behavioral and electrophysiological methods were used to investigate the hyperalgesia and allodynia, and functional changes in lumbar spinal dorsal horn neurons, in a model of neuropathic pain (Selzer et al. 1990) involving ligation of one-third to one-half of one sciatic nerve in rats. One and 5 weeks following ligation, there was a significant reduction in hind limb withdrawal latency to noxious radiant heat on the operated side and, to a lesser degree, on the unoperated side. By 16 weeks, heat withdrawal latencies were reduced about equally (approximately 40%) on both sides. Withdrawal threshold to mechanical pressure was markedly reduced within 1 week on the operated side, and decreased in a time-dependent manner on the unoperated side. Heat withdrawal latency and von Frey withdrawal thresholds were not significantly affected in sham-operated rats. The same rats were tested in a paradigm measuring the isometric force of hind limb withdrawals elicited by graded noxious contact heat stimuli (38-52 degrees C, 5 sec). Withdrawal force increased monotonically with stimulus temperature starting at a threshold of approximately 40 degrees C. Stimulus-response functions were not significantly different between a sham-operated group and groups tested 5 (acute) and 16 weeks (chronic) after partial sciatic nerve ligation. Following behavioral testing, the animals were deeply anesthetized with pentobarbital sodium to allow electrophysiological recording of responses of single lumbar dorsal horn wide-dynamic range-type neurons to mechanical and noxious thermal stimulation of the hind paw. Recordings were made from 6 sham-operated rats (26 neurons ipsilateral and 31 contralateral to the operated leg), from 7 rats receiving partial sciatic nerve ligation 5 weeks previously (29 ipsilateral and 29 contralateral to ligation), and from 7 rats receiving partial sciatic ligation 16 weeks previously (18 ipsilateral, 29 contralateral to ligation). In several ligated rats we were unable to find heat-responsive neurons with cutaneous receptive fields on the hind paw ipsilateral to the ligation. For the neurons that were sensitive to heat, responses increased monotonically from a threshold of 40-42 degrees C. Neuronal stimulus-response functions for heat were not significantly different between ipsi- and contralateral (to operated) sides in the sham, 5-week or 16-week post-ligation groups, or between sham and 5- or 16-week post-ligation groups. Mechanical receptive field areas were not significantly different between ipsi- and contralateral sides in the sham and 5-week post-ligation groups, or between sham and 5-week post-ligation groups. However, receptive field areas were significantly larger in the 16-week post-ligation group (both ipsi- and contralateral to ligation) compared to sham and 5-week post-ligation groups. The results suggest that allodynia may be associated with a chronic enhancement of neuronal mechanosensitivity, but that the thermal hyperalgesia is not associated with enhanced neuronal responsiveness or force of withdrawal.
Asunto(s)
Conducta Animal/fisiología , Hiperalgesia/fisiopatología , Nervio Ciático/lesiones , Médula Espinal/fisiología , Animales , Estimulación Eléctrica , Electrofisiología , Calor , Hiperalgesia/etiología , Contracción Isométrica/fisiología , Masculino , Mecanorreceptores/fisiología , Neuronas/fisiología , Dimensión del Dolor/efectos de los fármacos , Umbral del Dolor/fisiología , Estimulación Física , Ratas , Ratas Sprague-Dawley , TemperaturaRESUMEN
Airway obstruction from tongue edema following intraoral procedures is uncommon. However, the insidious nature of postoperative lingual edema and the gravity of acute airway obstruction requires diligent monitoring by the surgeon. The etiology of lingual edema is likely related to tissue ischemia, secondary to venous or arterial obstruction. This study shows that during normal usage the mouthgag can easily generate pressures which typically exceed venous pressure and often exceeds arterial pressure. Suspension of the mouthgag almost always exceeds arterial pressure. Whether that pressure is transferred to the respective arteries and veins is likely highly variable and relates to the patient's individual dentofacial anatomy. Avoidance of these high pressures should minimize the risk of postoperative lingual edema. The U.C. Davis Mouthgag Usage Protocol is presented.
Asunto(s)
Obstrucción de las Vías Aéreas/etiología , Edema/complicaciones , Complicaciones Posoperatorias , Enfermedades de la Lengua/complicaciones , Niño , Edema/etiología , Humanos , Intubación Intratraqueal/efectos adversos , Intubación Intratraqueal/instrumentación , Otolaringología/instrumentación , Presión , Instrumentos Quirúrgicos/efectos adversos , Enfermedades de la Lengua/etiologíaRESUMEN
The pregnant guinea pig may be a useful model for the study of drug effects in the newborn. A reliable technique for epidural catheterization in the guinea pig was developed to allow use of this model to evaluate the effects of epidural labor analgesics on neonates. Catheters were implanted in two open pilot animals and 19 time-dated pregnant animals on days 59 to 62 of gestation. After establishing a surgical plane of isoflurane-induced anesthesia, an incision was made over the dorsal lumbar part of the spine. The L3-4 intervertebral space was exposed to allow introduction of a caudally directed 27-gauge catheter into the epidural space. The catheter was capped and implanted subcutaneously, then the animal was allowed to recover from anesthesia. Catheter placement was evaluated, using a bupivacaine test dose in 17 animals and postmortem histologic examination in 20 animals. One animal died immediately after surgery. Epidural placement was confirmed histologically in 15 of 20 animals. Failed catheters were either subdural, with one catheter found to be penetrating the spinal cord (intraspinal), or intramuscular. Response to epidurally administered bupivacaine was variable but was typically characterized by normal alertness and ability to use the forelimbs; depression of the panniculus reflex in the dorsal lumbar region; and hind limb motor impairment, with ataxia, loss of the placing reflex, and a tendency to drag the hind limbs. Subdural placement was associated with CNS depression, recumbency, shallow breathing, and sensory block ascending to the level of the ears.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Analgesia Epidural/veterinaria , Analgesia Obstétrica/veterinaria , Cateterismo/veterinaria , Cobayas , Analgesia Epidural/métodos , Analgesia Obstétrica/métodos , Animales , Bupivacaína/administración & dosificación , Cateterismo/métodos , Femenino , EmbarazoRESUMEN
In monkeys, dogs and swine (six each) we tested the reduction of the isoflurane MAC (minimal alveolar concentration) produced by 2 mg.kg-1 morphine intravenously (i.v.) and the concurrent effect on PCO2 with spontaneous ventilation. MAC fell to a minimum of 55% of control at 53 min in monkeys, 50% at 38 min in dogs and 13% at 33 min in swine. PaCO2 rose at constant MAC with morphine to 55-60 mmHg, but did not fall over the next several hours despite the decline of plasma morphine concentration, and the resulting needed rise in isoflurane concentration to keep the anaesthesia depth at 1 MAC. After isoflurane concentration had returned to pre-morphine control levels, naloxone immediately reduced PaCO2 to or below control level. Morphine pharmacokinetics in the three species studied conformed to a two-compartment model.
Asunto(s)
Isoflurano/farmacología , Morfina/farmacología , Anestesia/veterinaria , Animales , Análisis de los Gases de la Sangre/veterinaria , Dióxido de Carbono/metabolismo , Perros , Interacciones Farmacológicas , Hemodinámica , Inyecciones Intravenosas/veterinaria , Macaca mulatta , Morfina/administración & dosificación , Morfina/farmacocinética , Presión Parcial , Alveolos Pulmonares/efectos de los fármacos , Radioinmunoensayo/veterinaria , Especificidad de la Especie , Porcinos , Porcinos EnanosRESUMEN
We determined the magnitude and duration of the effect of morphine (1.0 mg/kg intravenous bolus) on isoflurane and halothane minimum alveolar concentration (MAC) in six dogs anesthetized on two occasions in cross-over fashion. Plasma morphine concentration-time profiles and changes in PaCO2 were determined after morphine injection. After morphine injection, the end-tidal anesthetic dose was manipulated over the course of a 4-h observation period to account for the decline in plasma morphine concentration and to maintain an anesthetic level equivalent to 1.0 MAC isoflurane or halothane alone. Morphine decreased the MAC of halothane and isoflurane. The magnitude of MAC decrease was related to time after morphine injection and was similar for a given time with both halothane and isoflurane. For example, at 28.8 +/- 3.6 (mean +/- SE) and 34.8 +/- 6.3 min after morphine injection, the MAC for halothane and isoflurane were reduced by 35.7% +/- 4.5% and 39.3% +/- 3.4%, respectively. By 4 h after morphine injection, the MAC reduction for both anesthetics was less than 10% in most of the animals. Except for systemic clearance of morphine during halothane and isoflurane (40.1 +/- 6.1 and 53.7 +/- 5.6 mL.min-1.kg-1, respectively), there were no differences in disposition kinetics of free morphine associated with the two inhaled anesthetics. Morphine increased PaCO2 to a similar degree with both halothane (from 42.2 +/- 2.1 mm Hg to 55.6 +/- 2.3 mm Hg) and isoflurane (46.2 +/- 2.4 mm Hg to 55.3 +/- 2.1 mm Hg). Respiratory depression was abolished by noxious stimulation (tail clamp) and naloxone in all animals with both anesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Anestesia por Inhalación , Halotano/farmacocinética , Isoflurano/farmacocinética , Morfina/administración & dosificación , Alveolos Pulmonares/metabolismo , Animales , Dióxido de Carbono/sangre , Perros , Inyecciones Intravenosas , Masculino , Morfina/farmacocinética , Morfina/farmacologíaRESUMEN
The aim of this study was to examine the value of systematic preoperative pulmonary function tests (PFTs) in order to reliably predict prolonged stay in I.C.U., prolonged mechanical ventilation and mortality in elective cardiac surgical patients. 149 consecutive adult patients (valvular replacement or coronary bypass graft) were studied retrospectively. We examined the preoperative respiratory data: vital capacity (VC), first second forced expired volume (FEV1), PaCO2 and PO2. Length of stay in I.C.U. (LICU), duration of mechanical ventilation (DMV), incidence of reintubation and survival rate were used as indices of respiratory morbidity. The results of the present study clearly indicate that patients with impaired airway flow rates had a prolonged postoperative recovery following cardiac surgery. Mortality, ICV and DMV increased when FEV1 was less than 1.5 L, VC was less than 2.5 L, or PaO2 was less than 8.5 kPa. Reintubation was associated with impaired flow rates. Pulmonary function tests appeared effective in predicting postoperative complications and the need for prolonged ventilatory support.
Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Cuidados Preoperatorios , Pruebas de Función Respiratoria , Procedimientos Quirúrgicos Cardíacos/mortalidad , Femenino , Volumen Espiratorio Forzado , Humanos , Unidades de Cuidados Intensivos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Valor Predictivo de las Pruebas , Respiración Artificial , Estudios Retrospectivos , Tasa de Supervivencia , Capacidad VitalRESUMEN
Breathing was recorded via a pulsed ultrasonic flowmeter in 11 healthy subjects, at rest and during steady-state exercise (at 50% of their maximal O2 consumption) at both sea level (200 m) and simulated altitude (4,500 m in a hypobaric chamber). The pattern of breathing was quantified breath by breath in terms of classical respiratory variables (tidal volume and inspiratory and expiratory times), and the shape of the entire airflow profile was quantified by harmonic analysis. Statistical tests were used to compare the within-individual with the between-individual variations. In comparing the sea level vs. altitude rest (16% increase in ventilation) and sea level vs. altitude exercise (40% increase in ventilation) airflow profiles, we found a significantly greater resemblance within the individual than between individuals. Comparisons of sea level rest and exercise (295% increase in ventilation) and altitude rest and exercise (375% increase in ventilation) revealed no similarity within individuals. Despite airflow profile changes between rest and exercise, it is still possible to attest to a diversity of flow profile between individuals during exercise. Hypoxia at rest or during exercise does not alter the phenomenon of the individuality of breathing patterns.
Asunto(s)
Ejercicio Físico/fisiología , Hipoxia/fisiopatología , Mecánica Respiratoria/fisiología , Adulto , Altitud , Humanos , Masculino , Persona de Mediana Edad , Volumen de Ventilación PulmonarRESUMEN
We examined the specific effects of 7.5% hypertonic saline (HTS) on myocardial performance and regional blood flow and compared the efficacies of HTS and lactated Ringer's solution (LR) for hypovolemic resuscitation. Studies were performed in anesthetized dogs subjected to rapid hemorrhage to decrease mean arterial pressure by 50% over 60 min. The animals were resuscitated with either HTS (n = 8) at 5 ml/kg or LR (n = 7) at a dose required for equivalent restoration of cardiac output. Cardiac contractility was assessed using the slope Ees of the left ventricular end-systolic pressure-diameter relationship and regional blood flow was measured using radioactive microspheres. At 10 min after resuscitation, mean arterial pressure increased from 45.1 +/- 2.5 to 77.7 +/- 3.2 mmHg with HTS and 50.9 +/- 2.5 to 80.1 +/- 3.2 mmHg with LR. Resuscitation with either fluid caused significant increases in heart rate and similar decreases in vascular resistance. Cardiac contractility (Ees) did not change significantly with LR, whereas with HTS, Ees increased from 14.8 +/- 0.9 during hemorrhage to 19.4 +/- 1.6 as compared with a baseline value of 13.4 +/- 1.5 mmHg/mm. Hemorrhage decreased blood flow to various organs by 50% to 70% of baseline. Except for better improvement in splenic and hepatic perfusion with HTS, similar restoration of blood flow to the heart, muscle, skin, kidney, and jejunum was observed at 10 min after resuscitation with either fluid. In this animal model of rapid and severe hemorrhagic shock, HTS given at approximately one-sixth the volume of LR was equally effective in providing temporary restoration of hemodynamic function.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Hemodinámica , Contracción Miocárdica , Solución Salina Hipertónica/uso terapéutico , Choque/fisiopatología , Animales , Presión Sanguínea , Gasto Cardíaco , Perros , Femenino , Frecuencia Cardíaca , Masculino , Volumen Plasmático , Flujo Sanguíneo Regional , Choque/tratamiento farmacológico , Resistencia Vascular , VasodilataciónRESUMEN
To determine the suitability of the rhesus monkey as a model for investigation of opioids, we examined the analgesic, respiratory, and cardiovascular effects of fentanyl in six adult male rhesus monkeys. Fentanyl was administered in sequential bolus injections of 2, 4, 16, 64, and 128 micrograms/kg, with 10 min between each dose. Arterial plasma fentanyl concentrations and blood gas tensions were measured 3 and 9 min after each dose and 1, 2, 5, 20, 60, and 120 min after the final dose. At the same time periods, mean systemic arterial, pulmonary arterial, central venous, and pulmonary capillary wedge pressures, cardiac output, heart rate, and respiratory rate were measured. Analgesia was quantified as the time required for tail withdrawal from a standardized noxious stimulus. Tail latency response time increased significantly after the 4-microgram/kg dose (plasma fentanyl concentration = 2.7 +/- 0.9 ng/mL). Maximum tail latency response time was attained after the 64-micrograms/kg dose (43.4 +/- 26.0 ng/mL). Respiratory rate decreased significantly after the 2-microgram/kg dose, and PaCO2 increased significantly after the 4-microgram/kg dose. All animals became apneic, requiring tracheal intubation and controlled ventilation, after the 64-micrograms/kg dose. Also, mean arterial pressure and cardiac output decreased significantly after the 64-micrograms/kg dose. There were no other significant cardiovascular changes. Peak plasma fentanyl concentration after the 128-micrograms/kg dose was 117.0 +/- 49.6 ng/mL. It appears that plasma concentrations of approximately 40 ng/mL are sufficient to reach the full cardiovascular, respiratory, and analgesic effects of fentanyl in the rhesus monkey. Significant respiratory and analgesic effects are evident at concentrations as low as 3 ng/mL.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Analgesia , Sistema Cardiovascular/efectos de los fármacos , Fentanilo/farmacología , Sistema Respiratorio/efectos de los fármacos , Animales , Presión Sanguínea/efectos de los fármacos , Dióxido de Carbono/sangre , Gasto Cardíaco/efectos de los fármacos , Fentanilo/administración & dosificación , Fentanilo/sangre , Frecuencia Cardíaca/efectos de los fármacos , Hemodinámica/efectos de los fármacos , Macaca mulatta , Masculino , Modelos Biológicos , Narcóticos/toxicidad , Respiración/efectos de los fármacosRESUMEN
The endogenous opiate system is thought to play a unique role in the adaptive response to hypoxia during the fetal and neonatal period. Exogenous opiates used as analgesics during labor may also affect this adaptive response. Infant monkeys (Macaca mulatta) were exposed to oxygen deprivation (15-min period breathing 12% O2) on the day of birth. One half of the infants had been exposed to meperidine during parturition via treatment of the dam (2 mg/kg, i.v.). An additional control group received neither treatment. All infants were evaluated for growth, development and neurobehavioral performance over a subsequent 14-week period. Compared to controls, infants exposed to oxygen deprivation had somewhat slower weight gains during the early neonatal transition from weight loss to weight gain, were less responsive to sensory stimulation on the day of the oxygen deprivation episode, slept more on the first night after the episode, had fewer active and mature behaviors during a 3-week period of rapid motor development, and had impaired fine motor skills. Prior exposure to labor analgesia apparently prevented many of these effects. Use of opiate drugs during the perinatal period needs to take into account the unique properties and functions of the endogenous opiate system during this developmental period.
Asunto(s)
Animales Recién Nacidos/crecimiento & desarrollo , Conducta Animal/efectos de los fármacos , Hipoxia Fetal/etiología , Meperidina/farmacología , Animales , Femenino , Hipoxia Fetal/fisiopatología , Trabajo de Parto , Macaca mulatta , Embarazo , Reflejo/efectos de los fármacos , Factores de Tiempo , Aumento de Peso/efectos de los fármacosRESUMEN
Most patients receiving spinal narcotics can be monitored adequately by well-trained nurses on postoperative or postdelivery wards. Patients at high risk (e.g., those with preexisting lung disease or many elderly patients) do need monitoring in the intensive care unit. Also requiring special monitoring are patients for whom epidural narcotics alone will not cover their pain, such as young patients with multiple trauma. Patients without these restrictions, however, can be monitored successfully outside the intensive care unit, although the dose of epidural narcotic should be kept as low as possible.
Asunto(s)
Analgésicos Opioides/efectos adversos , Unidades de Cuidados Intensivos , Monitoreo Fisiológico/instrumentación , Dolor Postoperatorio/tratamiento farmacológico , Insuficiencia Respiratoria/inducido químicamente , Analgésicos Opioides/administración & dosificación , Humanos , Inyecciones Epidurales , Inyecciones Espinales , Factores de RiesgoRESUMEN
Peripheral plasma beta-endorphin (BEP) was measured in 10 pregnant monkeys during the third trimester (14-21 weeks gestation, term = 23.5 weeks). The study was intended to identify a late-pregnancy rise in BEP that has been reported in women. Levels rose in late pregnancy only in animals that delivered within a few days of the final sample. When both BEP and beta-lipoprotein (BLP) were measured in a further group of 10 animals, the late-pregnancy BEP rise was not accompanied by a rise in BLP. Multiple regression indicated that plasma BEP was correlated with plasma cortisol but that an independent influence of gestational age could be detected. We conclude that monkeys exhibit a rise in BEP just prior to parturition that is not accompanied by increases in cortisol and BLP that would indicate general maternal pituitary activation.
Asunto(s)
Endorfinas/sangre , Preñez/metabolismo , Animales , Femenino , Edad Gestacional , Hidrocortisona/sangre , Lipoproteínas/sangre , Macaca mulatta , Embarazo , Radioinmunoensayo , Factores de TiempoRESUMEN
Infant monkeys (Macaca mulatta) exposed to narcotic analgesics during labor after treatment of dams were evaluated for growth and development over a 14-week period. Ten infants exposed to meperidine (2 mg/kg maternal dose) or alfentanil (0.1 mg/kg maternal dose) were compared with seven controls whose dams received no analgesic. No group differences in weight gain or body growth were observed. Alfentanil-exposed infants appeared to have a higher incidence of infections requiring veterinary treatment. Measures of spontaneous activity showed a significantly higher incidence of immature rest pattern (laying) in the alfentanil group associated with lower overall locomotor activity relative to controls. Meperidine-exposed infants had a generally higher overall level of locomotor activity than controls that was statistically significant at 11 weeks of age. Alfentanil-exposed animals were impaired in performance of a simple cognitive task (object constancy) at 2 to 3 months of age and meperidine-exposed infants showed a similar nonsignificant trend. Gross and fine motor maturations were similar to those of controls. Thus, in this situation, the impact of obstetric analgesic treatment was demonstrable for several months after birth in some limited areas.
Asunto(s)
Analgesia , Animales Recién Nacidos/crecimiento & desarrollo , Parto Obstétrico , Fentanilo/análogos & derivados , Meperidina , Alfentanilo , Animales , Conducta Animal/fisiología , Cognición/fisiología , Femenino , Salud , Macaca mulatta , Actividad Motora/fisiología , EmbarazoRESUMEN
Maternal-fetal disposition and neonatal respiratory depressant effect of narcotic analgesics were studied by administration of meperidine (2 mg/kg, IV) or alfentanil (IV infusion, 0.1 mg/kg total dose) during labor in rhesus monkeys. Fetal/maternal plasma ratios were lower for alfentanil, the more highly protein-bound drug (fetal/maternal ratio 0.20 at birth versus 0.46 for meperidine). However, elimination of alfentanil was delayed in the neonate. Indeed, plasma concentrations of alfentanil increased during the first 2 postnatal hours, indicating a compartmental shift from tissues to circulation in the neonate. As regards respiratory depression, six of ten narcotic-treated monkeys had suboptimal (less than 60 breath/min) respiratory rates at birth. Respiratory rate was negatively correlated with cord vein normeperidine and meperidine levels; the strongest correlation was with normeperidine (r = -0.84, P less than 0.01). Neonatal normeperidine elimination in the postnatal period was prolonged, as has also been observed in humans. These studies serve as a basis for comparing the neonatal neurobehavioral effects of the two analgesics and support the use of the rhesus monkey as an animal model to further understanding of the effects of narcotic analgesics on neonatal respiration.
Asunto(s)
Anestesia Obstétrica , Fentanilo/análogos & derivados , Trabajo de Parto , Intercambio Materno-Fetal , Meperidina/farmacocinética , Alfentanilo , Anestesia Intravenosa , Animales , Femenino , Fentanilo/administración & dosificación , Fentanilo/sangre , Fentanilo/farmacocinética , Sangre Fetal/análisis , Macaca mulatta , Meperidina/administración & dosificación , Meperidina/sangre , Embarazo , Unión Proteica , Insuficiencia Respiratoria/inducido químicamenteRESUMEN
Neurobehavioral evaluations were conducted in neonatal monkeys (Macaca mulatta) exposed to narcotic analgesics during labor through their dams. Infants exposed to meperidine (2 mg/kg maternal dose) or alfentanil (0.1 mg/kg maternal dose) were compared with controls whose dams received no analgesic. Meperidine and alfentanil differ in pharmacologic properties related to maternal-fetal transfer and neonatal metabolism. Drug-exposed infants showed neurobehavioral effects over the first 3 days of life including depressed respiration (at birth), depressed environmental response to aversive stimuli (days 0, 1, and 2), more overnight sleep (day 1), and more quiet behavior patterns while awake (day 3). In addition, drug exposure was associated with increased elicited muscle tone early in the neonatal period and earlier maturation of sitting, standing, and walking. No effects on growth or health were noted, but drug-exposed infants had lower hematocrits and an earlier onset of a linear growth rate as reflected in body weight. No qualitative or quantitative differences were noted between the two drug treatments. Because behavioral effects were seen after the drug was eliminated, a direct pharmacologic action of the drug does not fully explain the findings.