Efectos fetales de la anestesia espinal materna. Dr. Alberto López Bascope

2. 1. Anestesia Regional en Obstetricia: qué repercusión
existe en la dualidad Materno/Fetal?
2. Cómo afecta la hipotensión en la Anestesia Espinal?
3. Analizar brevemente la circulación fetal.
2. Revisar la fisiología de la Oxigenación fetal.
3. Qué implicaciones prácticas se pueden concluir?.

4. Haggard HW: 1929
Devils, Drugs, and Doctors: The Theory of the
Science of Healing from Medicine Man to Doctor

6. Porque oí un grito como de mujer de parto, angustia como de
primeriza; era el grito de la hija de Sion que se ahogaba, y
extendía sus manos, diciendo: ¡Ay ahora de mí, porque
desfallezco ante los asesinos!
Jeremías 4:31

7. 1. Parto o Cesárea?
2. Cuánto tiempo se dispone?
3. Cuál es el pronóstico del niño?
4. Condición anatómo/fisiológica de la madre?
5. Opciones Anestésicas:
• Anestesia General
• Anestesia Regional:
1. Espinal
2. Peridural
3. Mixta

8. Factores que afectan la
transferencia placentaria de
medicamentos (Materno/Fetal)
Drogas que cruzan la Placenta

9. A 1995 landmark study by Riley established the advantages of spi-
nal compared with epidural anesthesia for cesarean delivery.
1. Riley ET, Cohen SE, Macario A, Desai JB, Ratner EF. Spinal versus epidural
anesthesia for cesarean section: a comparison of time efficiency, costs,
charges, and complications. Anesth Analg 1995;80:709–12
2. Riley ET. Spinal anaesthesia for Caesarean delivery: keep the pressure
up and don’t spare the vasoconstrictors. Br J Anaesth,2004;92:459–61.
Neuraxial Anesthesia for Cesarean Delivery:
What Criteria Define the “Optimal” Technique?
Dan Benhamou, MD, Anesth & Analg,
Vol. 109, No. 5, Nov. 2009
The neonate may also be adversely affected by maternal
hypotension and reduced uteroplacental perfusion. In most
instances, however, maternal hypotension of short duration is
associated with transient fetal carbon dioxide retention and is
of limited clinical consequence.

11. Maternal haemodynamic changes during spinal
anaesthesia for caesarean section
Eldrid Langesæter, Current Op in Anesth, 2011, 24:242–248
Key points
1. The typical haemodynamic effects of spinal anaesthesia in
healthy pregnant women are a decrease in systemic vascular
resistance and a compensatory increase in cardiac output;
phenylephrine is, thus, the first-line vasopressor.
2. The rarer presentation of hypotension and bradycardia should
be treated with ephedrine and/or anticholinergics.

12. SUMMARY
 Spinal is commonly for caesarean. Advantages for the mother: remaining
awake for the birth, no risks of General and facilitating POP pain relief. The
commonest side-effect of spinal is hypotension, which is often
accompanied by nausea or vomiting, or both. Severe hypotension poses
serious risks to mother (loss of consciousness) and baby (lack of O2 and
brain damage).
 The review found that no single method completely prevents hypotension,
but the incidence is reduced by administering IV fluids, ephedrine or
phenylephrine, and by compressing the legs with bandages, stockings or
inflatable boots.

14. Conclusion:
There is not one accepted definition of hypotension in the scientific
literature. The incidence of hypotension varies depending on the chosen
definition. Even minor changes of the definition cause major differences in
the frequency of hypotension.

15. 1. Incidencia de hipotensión: 50% a 80%.
2. La simpatectomía causa vasodilatación y consecuente disminución
de RVS.
3. La presión baja disminuye el flujo sanguíneo en la art. uterina, lo
que indi-rectamente afecta al feto. Si persiste puede ocurrir acidosis
fetal. (10 min de Flujo - 65% = Acidosis).

16. Clin Chest Med
32 (2011) 15–19

18. Intrapartum Fetal Pulse Oximetry:
Clinical Application
Vol 55(3), March 2000, pp 173-183
The normal range of fetal arterial oxygen saturation
(FSpO2), 30 to 70%, lies in the middle of the O2
dissociation curve, so that small changes in pH or PO2
cause large changes in FSpO2

20. Curva de saturación de la oxihe-
moglobina para el feto (A) y adulto (B)
Patrón circulatorio en el útero

21. DETERMINANTS OF FETAL
OXYGENATION
The fetus has made four major adaptations to compensate for the low PO2.
1. The rate of perfusion of fetal organs in sheep preparations is 2.5-fold
greater than blood flow to the same organs in the adult.
2. Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin.
3. Third, fetal hemoglobin levels are increased over adult values.
4. A system of vascular shunts and streaming effects directs oxygenated
blood to high-priority tissue in the liver, heart, and brain and guides
deoxygenated blood back to the placenta.
Adkinson: Middleton's Allergy:
Principles and Practice, 7th ed.

23. Sir Joseph Barcroft first drew a close analogy between the low partial pressure
of oxygen of the fetus in utero and that which would be found in humans at an
altitude of 30,000 to 33,000 ft on Mt. Everest when he observed, ‘‘The fetus then
grows in an environment the oxygen concentration of which is falling all the
time—an uphill business you may say. True indeed, for is it not the problem of
Everest, the maintenance of the organism in the atmosphere becoming
progressively rarer?’’ He later neatly summarized this concept with the phrase,
‘‘Mt. Everest in utero.’’
1. Barcroft J. The conditions of foetal respiration. Lancet
1933;222(5749):1021–4.
2. Barcroft J. Researches in prenatal life. London: 1946.
Clin Perinatol, 36 (2009) 655–672

24. In conclusion, we found that labor CSE in patients with cervical
dilation >3 cm, ruptured membranes, and fetal descent, does not
significantly alter fetal oxygenation. The impact of labor CSE on
FSpO2 is minimal and appears similar to epidural analgesia.

25. Pathophysiology of Fetal
Growth Restriction: EXTRÍNSICAS
Implications for Diagnosis • Tabaquismo
and Surveillance • Alcoholismo
Ahmet Alexander Baschat, MD
• Drogadicción
• Infecciones virales
MATERNAS FAC. PLACENTARIOS
• Hipertensión DESÓRDENES EN EL • Mosaicismo
• Pre-eclampsia DESARROLLO • Implantación anormal
• Sx. antifosfolipidos FETAL • Útero anormal
• Trombofilia • Abruptio plac. crónico
FETAL
CAUSAS Y • Trisomías cromosómicas
CONDICIONES • Desórdenes Mendelianos
• Alt. Anatómicas congénitas
Vol 59, Number 8 • Otros Síndromes
OBSTETRICAL AND
GYNECOLOGICAL SURVEY

26. Metabolic adaptation at birth
Ward Platt M AUG-2005; 10(4): 341-50
Seminars in Fetal & Neonatal Medicine
Newcastle Neonatal Services, Royal Victoria Infirmary, Department of Child Health, Queen
Victoria Road, Newcastle upon Tyne NE1 4 LP, UK.
Abstract:
The neonate must make a transition from the assured continuous
transplacental supply of glucose to a variable fat-based fuel
economy. The normal infant born at term accomplishes this
transition through a series of well-coordinated metabolic and
hormonal adaptive changes.

27. The Internet Journal of Gyn anMd Obst, 2008 : Vol 9 Number 2
Intrapartum Fetal Resuscitation: A Review
Dushyant Maharaj MBBS
1. DISMINUCIÓN EN LA FRECUENCIA CARDÍACA.
2. REDUCCIÓN EN EL CONSUMO DE O2, SECUNDARIO
A CESE DE FUNCIONES NO ESCENCIALES.
3. REDISTRIBUCIÓN DEL GC A ÓRGANOS VITALES.
4. INCREMENTAR EL METABOLISMO CELULAR ANAEROBIO.

28. Bearing in mind that the intrauterine PO2 amounts to only 25–30mmHg in contrast
to the adult 90–100 mmHg, this would enable the fetus to maintain a similar
metabolic rate to the mother despite a much lower PO2 and, thus, would exactly
correspond to the metabolic adaptation of fetal mammals
Metabolic adaptation to hypoxia:
cost and benefit of being small
Dominique Singer
Respiratory Physiology & Neurobiology
141 (2004) 215–228

29. Foca de Weddell

30. Nutrientes y Alteración en Hipercapnea
Oxígeno Intercambio gas Fetal
Respuesta al Hipoxemia Acidosis
estrés Fetal Respiratoria
Disminución del
Crecimiento
Metabolismo
Anaeróbico
Bradicardia e
Hipotensión
Perfusión a Acidosis
Órganos vitales Láctica
Sufrimiento de Muerte Fetal
Órganos Intraútero

31. Perinatal asphyxia pathophysiology in pig and human:
A review
Animal Reproduction Science xxx (2005) xxx–xxx
María Alonso-Spilsbury, Daniel Mota-Rojas

32. Intrapartum Assessment of the Fetus: Historical
and Evidence-Based Practice
Gary A. Dildy III, M
Obstet Gynecol Clin N
Am
32 (2005) 255– 271

33. The Timing of Birth
A hormone unexpectedly found in the human placenta turns out to
influence the timing of delivery. This and related findings could
yield much needed ways to prevent premature labor
Scientific American March 1999

34. Endocrinology of Parturition
Victoria Snegovskikh, MD
Endocrinol Metab Clin N Am
35 (2006) 173–191

35. Endocrinology of Parturition
Victoria Snegovskikh, MD
Endocrinol Metab Clin N Am
35 (2006) 173–191

37. CVCI CA Resistencia Tono Hb
miometral:
Viscocidad
SO2
Hb
Vascular sanguínea
• tono
• contracciones
Hipotensión
Sistémica
Pr. Vena . Uterina Pr. Art . Uterina Resistencia
Intrínsica
Presión Resistencia
Perfusión Vascular
Uterina Uterina
Pr y Flujo Sanguíneo Uterino Contenido de O2
Aporte Uterino: Nutientes y O2

38. RESUCITACION CARDIOPULMONAR
EN LA EMBARAZADA
Dr. MAURICIO VASCO RAMÍREZ

39. MONITOREO:
• Tococardiografía, pH Fetal
• Lactato Fetal, Pulso Oximetría Fetal
OPTIMIZAR O2 MATERNO
• Administración de O2 a Pr. mormal
• O2 a Presión Positiva
OPTIMIZAR PERF. PLACENTARIA
• Adecuar / discontinuar Occitocina,
• Tocolíticos: disminuir hiperestimu-
lación

40. • Efedrina: cruza la placenta y al aumentar el metabolismo fetal
puede producir acidosis fetal y taquicardia materno/fetal
• Fenilefrina: no altera la perfusión, ni genera acidosis, pero
bradicardiza al feto y la madre.
COMBINACIÓN EFECTIVA: FENILEFRINA + EFEDRINA + CO-
HIDRATACIÓN + MANIOBRAS FÍSICAS

41. OPTIMIZAR PERFUSIÓN UTERINA:
• Lateralización materna
• Vasopresor + Carga de cristaloide
MEJORAR FLUJO UMBILICAL:
• Amnio-infusión
• Cambio posicional a la madre
PARTO:
• Evitar Prematurez, y trabajo de Parto
• Anestesia Regional para Cesárea

42. Posición y Circulación Uterina
Intrauterine Resuscitation: Active
management of Fetal Distress
JA Thurlow
Int. J of Obst Anesthesia
2002, 11, 105-116

43. Efficacy of intrauterine resuscitation techniques in
improving fetal oxygen status during labor
Simpson KR - Obstet Gynecol - 01-JUN-2005; 105(6)
Intrauterine Resuscitation: Active
management of Fetal Distress
JA Thurlow, Int. J of Obst Anesthesia
2002, 11, 105-116

44. Birth Asphyxia and Cerebral Palsy
Jeffrey P. Phelan, MD
Clin Perinatol
32 (2005) 61– 76

46. Do hyperoxaemia and hypocapnia add to the risk of
brain injury after intrapartum asphyxia?
G Klinger, J Beyene, P Shah, M Perlman
Arch Dis Child Fetal Neonatal Ed 2005;90
ORIGINAL ARTICLE
Conclusions:
Severe hyperoxaemia and severe
hypocapnia were associated with adverse
outcome in infants with post asphyxial HIE.
During the first hours of life, oxygen
supplementation and ventilation should be
rigorously controlled.
Current North American neonatal resuscitation guidelines recommend the use
of 100% inspired oxygen, whereas British guidelines suggest that ‘‘it may be
more appropriate to use an inspired oxygen concentration of 40% initially and
increase this if required’’.

47. Intrauterine resuscitation during labor: should maternal
oxygen administration be a first-line measure?
Simpson KR - Semin Fetal Neonatal Med, 01-DEC-2008; 13(6): 362-7
Recent evidence suggests potential risks to the mother and fetus or
newborn. Even small increases in maternal and fetal Po2 as a result
of maternal O2 administration can produce O2 free radical activity in
mothers and fetuses. The potential long-term effects are unknown.
Caution should be exercised when considering maternal O2
administration as a first-line intrauterine resuscitation measure

48. Optimal Oxygen Saturation for Preterm Babies
Do We Really Know?
The James Cook University Hospital, Middlesbrough, UK
Biol Neonate, Review, Win Tin, 2004;85:319-325
O2 is the most commonly used 'drug' in neonatal units as an
integral part of respiratory support.
History of Neonatal Resuscitation - Part 2: Oxygen and Other Drugs
Michael Obladen
Dept. of Neonatology, Charité Un. Medicine, Berlin, Germany
Neonatology 2009;95:91-96
O2 was used in neonatal resuscitation from 1780, within 5 years of
its detection. It rapidly gained general acceptance and infiltrated
delivery rooms and, a century later, neonatal special care units.
After 217 years without scientific evidence, the use of O2 for
neonatal resuscitation has recently been questioned.

49. The Indian Anaesthetists, October 2004(1), Dr. Sunanda Gupta MD
SUPPLEMENTARY OXYGEN ADMINISTRATION DURING REGIONAL
ANAESTHESIA FOR LSCS – IS IT JUSTIFIED?
1. There be no significant increase in the maternal – fetal O2 transfer rate
when O2 tension is raised on the maternal side, since with the increase
in O2 tension of the perfusing blood, there is probably a concomitant
vasoconstriction which negates any positive effects that might be
expected as a result of increasing the maternal-fetal O2 gradient.
2. Breathing high FiO2 modestly increased fetal
oxygenation, but caused a concomitant increase in O2
Free Radical activity in both mother and fetus.

50. Air versus oxygen for resuscitation of
infants at birth
Tan A, Schulze A, O'Donnell CPF, Davis PG. Last Update:
09/12/2006
NICHD Cochrane Neonatal Home Page
Introduction to Neonatal Systematic
Reviews
Conclusión
Por lo tanto, sobre la base de la evidencia actualmente
disponible, si se elige el aire ambiental como gas inicial
para la reanimación, se debe seguir garantizando la
disponibilidad de O2 complementario.

51. Resuscitation of Newborn Infants with 21% or
100% Oxygen: An Updated Systematic Review
and Meta-Analysis
Systematic Review and Meta-Analysis
Vol. 94, No. 3, 2008, Ola Didrik Saugstad, M. Vento
Conclusions:
Recent Advances in
Neonatal Medicine
There is a significant reduction in the risk of neonatal
mortality and a International Symposium the risk of
An trend towards a reduction in
Honoring Prof. Ola Didrik Saugstad
severe hypoxic ischemic encephalopathy in newborns
Würzburg, Oct 2–4, 2008
resuscitated with 21% O2.
…coining the term ‘the oxygen radical disease of the newborn’ in which
he speculated that retinopathy of prematurity, bronchopulmonary
dysplasia, necrotizing enterocolitis, patent ductus arteriosus and
periventricular leukomalacia are different facets of one disease…

52. The human fetus develops in a profoundly hypoxic environment.
Thus, the foundations of our physiology are built in the most
hypoxic conditions that we are ever likely to experience: the womb.
This magnitude of exposure to hypoxia in utero is rarely experienced in adult
life, with few exceptions, including severe pathophysiology in critical illness and
environmental hypobaric hypoxia at high altitude. Indeed, the lowest recorded
levels of arterial oxygen in adult humans are similar to those of a fetus and were
recorded just below the highest attainable elevation on the Earth’s surface: the
summit of Mount Everest. We propose that the hypoxic intrauterine environment
exerts a profound effect on human tolerance to hypoxia.
Cellular mechanisms that facilitate fetal well-being may be amenable to
manipulation in adults to promote survival advantage in severe hypoxemic
stress.

53. Concepts in hypoxia Therapy for hypoxemic
reborn critically ill adults:
Daniel S Martin, Critical Care, potential therapeutic
2010, 14:315 targets

54. Permissive Hypoxemia
Is It Time To Change Our Approach?
Mohamed Abdelsalam, MD, CHEST / 129 / 1 / JAN,, 2002
2006
Goal-Directed Therapy for Severely Hypoxic Patients
With ARDS: Permissive Hypoxemia
M. Abdelsalam MD, RESPIRATORY CARE, Nov, 2010 vol 55 No 11
Cuáles son los riesgos potenciales de la Hipoxemia Permisiva?,
Se tolera igual en todos los órganos y sistemas?
Órganos diferentes tienen tolerancia diferente a la hipoxemia. Por
ejemplo un cerebro sano, puede en general, tolerar mejor la
hipoxemia, a condición de que la perfusión cerebral se mantenga.
En general, la estrategia de hipoxemia permisiva
significa mantener el O2 entre 82 y 88% de SaO2