Across the Lifespan Flashcards
how does pregnancy affect minute ventilation?
Progesterone is a respiratory stimulant. It increases minute ventilation up to 50%
- Vt increased by 40%
- RR increased by 10%
how does pregnancy affect the mother’s arterial blood gas?
Progesterone is a respiratory stimulant. It increases minute ventilation up to 50%. As a consequence, mom’s PaCO2 falls, and she develops respiratory alkalosis. Renal compensation eliminates bicarbonate to normalize blood pH. A small reduction in physiologic shunt explains the mild increase in PaO2. This increases the driving pressure of oxygen across the fetoplacental interface and improves fetal gas exchange.
- Arterial pH= no change
- PaO2 = increased (104-108 mmHg)
- PaCO2= Decreased (28-32 mmHg)
- HCO3= decreased ( 20mmol/L)
How does pregnancy affect the oxyhemoglobin dissociation curve?
Right shift (increase P50)-> facilitates O2 offloading to the fetus
How does pregnancy affect the lung volumes and capacities?
Functional residual capacity is reduced as a function of a decrease in expiratory reserve volume and residual volume (ERV decreases more than RV)
An increased oxygen consumption paired with a decreased FRC hastens the onset of hypoxemia. Failure to reverse hypoxemia results in brain death of the mother and the fetus
how does cardiac output change during pregnancy and delivery
How do blood pressure and systemic vascular resistance change during pregnancy?
Who is at risk for aortocaval compression, and how do you treat it?
In the supine position, the gravid uterus compresses both the vena cava and the aorta. This decreases venous return to the heart as well as arterial flow to the uterus and lower extremities. Decreased CO compromises fetal perfusion and can also cause the mother to lose consciousness.
By displacing the uterus away from the vena cava and aorta, we can reduce its compressive effects. We can accomplish this by elevating the mother’s right torso 15 degrees. It should be used for anyone in their 2nd (14-26 weeks) or 3rd trimester
How does the intravascular fluid volume change during pregnancy?
Intravascular fluid increases 35%
* plasma volume increases 45%
* erythrocyte volume increases 20%
What hematologic changes accompany pregnancy
- Clotting factors 1, 7, 8, 9, 10, 12 increase
- anticoagulants: Proteins S decreases and no change in protein C
- fibrin breakdown increases
- anti-fibrinolytic system: 11 & 13 decrease
How does MAC change during pregnancy?
MAC is decreased by 30-40%. This is probably due to increased progesterone.
How does pregnancy affect gastric pH and volume?
Pregnancy increases gastric volume and decreases gastric pH. This is due to increased gastrin.
How does pregnancy affect gastric emptying?
Before onset of labor = No change
After onset of labor = Slowed
How does pregnancy affect uterine blood flow?
Non-pregnant state = 100mL/min
Pregnancy at term = up to 700mL/min or 10% of the cardiac output (some texts say up to 800 or 900mL/min)
What conditions can reduce uterine blood flow?
uterine blood flow does NOT autoregulate- therefore, it is dependent on MAP, CO, and uterine vascular resistance (UVR).
Causes of reduced uterine blood flow:
* decreased perfusion: Maternal HoTN (sympathectomy, hemorrhage, aortocaval compression)
* increased resistance: Uterine contraction, HTN conditions that increase UVR
Uterine blood flow= (uterine artery pressure- uterine venous pressure)/ Uterine vascular resistance
Discuss the use of phenylephrine and ephedrine in the laboring pt.
Classic teaching states that phenylephrine increases uterine vascular resistance and reduces placental perfusion.
More recent evidence suggest that phenylephrine is as efficacious as ephedrine in maintaining placental perfusion and fetal pH in healthy mothers. In fact, mothers that received phenylephrine had higher fetal pH values (less fetal acidosis)
Which law determines which drugs will pass through the placenta?
The Fick principle determines which drugs can pass across the placenta.
Rate of diffusion (Diffusion coefficient x surface area x concentration gradient (between mom and fetus)/ membrane thickness
Drug characteristics that favor placental transfer:
* Low molecular weight < 500 Daltons (most anesthetic drugs and smaller than 500 Daltons)
* High lipid solubility
* nonionized
* nonpolar
Define the 3 stages of labor.
stage 1: beginning of regular contraction to full cervical dilation (10cm)
Stage 2: full cervical dilation to delivery of the fetus (pain in the perineum begins during stage 2)
Stage 3: Delivery of the placenta
How does uncontrolled labor pain affect the mother and the fetus?
May result in:
* increased maternal catecholamines -> HTN -> reduced uterine blood flow to the fetus
* maternal hyperventilation -> leftward shift of oxyhgb curve-> reduced delivery of O2 to the fetus
Compare and contrast the pain that results from the first and second stages of labor.
First stage:
* pain begins in the lower uterine segment and the cervix
* origin: T10-L1 posterior nerve roots
Second stage:
* Adds in pain impulses from the vagina, peritoneum, and pelvic floor.
* origins: S2-S4 posterior nerve roots
Compare and contrast the regional anesthetic technique that can be used for first and second stage labor pain.
Neuraxial techniques that provide analgesia to T10-L1 during the first stage of labor must be extended to cover S2-S4 during the second stage of labor
compare and contrast bupivicaine and ropivicaine for labor
discuss the use of 2-chloroprocaine for labor
- Useful for emergency C/S when epidural is already in place (very fast onset)
- metabolized by pseudocholinesterase in the plasma- minimal placental transfer
- antagonized opioid receptor (mu & kappa) and reduces the efficacy of epidural morphine
- risk of arachnoiditis when used for spinal anesthesia due to preservatives
- solutions without methylparaben and metabisulfite do not cause neurotoxicity
discuss the consequences of an epidural that is placed in the subdural space.
Although a rare and unpreventable event, It is possible to position the tip of the epidural catheter in the subdural space - between the dura and the arachnoid. Neither catheter aspiration nor a test dose will rule out subdural placement.
Within 10-25 minutes after the epidural is dosed, the patient will experience symptoms of an excessive cephalad spread of local anesthetic. Because the subdural space is a potential space, it holds a very low volume. For this reason, the block height for a given amount of local anesthetic will be much higher than if the same volume was administered in the epidural space.
What is the treatment for a total spinal?
A total spinal may result from:
* an epidural dose injected into the subarachnoid space
* an epidural dose injected into the subdural space
* a single shot spinal after a failed epidural block
Initial tx includes: vasopressors, IVF, left uterine displacement, elevation of the legs, and intubation if LOC
Discuss the fetal heart rate
The fetal heart rate is a surrogate measure of overall fetal wellbeing. it provides an indirect method to assess fetal hypoxia and acidosis. The use of this modality guides clinical decision-making so that we can minimize risk of fetal injury and demise
Fetal oxygenation is a function of uterine and placental blood flow. The fetus responds to stress with peripheral vasoconstriction, HTN, and a baroreceptor- mediated reduction in heart rate
Which fetal decelerations are unremarkable? which ones are cause for concern?
early decels do not present a risk of fetal hypoxemia, while late and variable decels require urgent assessment of fetal status
* variable decels: cord compression
* early decels: head compression
* Accelerations: OK or give O2
* Late Decels: placental insufficiency
VEAL CHOP
Define premature delivery, and list the potential complications from its occurance.
defined as delivery before 37 weeks gestation or less than 259 days from the last menstrual cycle. It is the leading cause of perinatal morbidity and mortality, and this risk is even higher for newborns weighing less than 1500g. This incidence of prematurity rises with multiple gestations and premature rupture of membranes.
Complications of premature delivery include:
* respiratory distress syndrome
* intraventricular hemorrhage
* NEC
* hypoglycemia
* hypocalcemia
* Hyperbilirubinemia
Discuss the use of steroids and tocolytic agents in the prevention of premature delivery.
Corticosteroids: (betamethasone) hasten fetal lung maturity. These drugs begin to take effect within 18 hours, with a peak benefit at 48hrs
Tocolytic agents: stop labor around 24-48 hours. They provide a bridge that allows the corticosteroids time to work. Antibiotic prophylaxis for chorioamnionitis is also given at this time. Tocolytic agents or corticosteroids are seldom given after 33 weeks gestation
What are the side effects of beta-2 agonists when used for tocolysis?
Beta-2 agonists: Terbutaline, Ritodrine
Side effects:
* hypokalemia results from intracellular potassium shift.
* Beta-2 agonists cross the placenta and may increase FHR
* Hyperglycemia results from glycogenolysis in the liver
* the newborn of hyperglycemia mother is at risk of post-delivery hypoglycemia. The mother’s glucose supply is gone, but the insulin in the neonatal circulation remains
What are the effects of hypermagnesemia?
Side effects:
* Apnea
* HoTN
* Skeletal muscle weakness (synergism with nondepolarizers)
* CNS depression
* Reduced responsiveness to ephedrine and phenylephrine
What is the tx for hypermagnesemia?
- supportive measures
- Diuretics (to facilitate excretion of Mg)
- IV calcium (to antagonize Mg)
How can oxytocin be administered? What are potential side effects?
Oxytocin is synthesized in the supraoptic and paraventricular (primary) nuclei of the hypothalamus. It is released from the posterior pituitary gland.
You can give it IV (diluted in IVF), or the OB can inject it directly into the uterus.
Side effects:
* Water retention
* Hyponatremia
* reflex tachycardia
* Coronary vasoconstriction
how can methergine be administered?
Methergine is a ergot alkaloid. It can be given 0.2 mg IM (not IV)
IV administration can cause significant vasoconstriction, HTN, and cerebral hemorrhage
What are the pros and cons of general anesthesia for cesarean section?
Mortality is 17x higher with a general anesthetic
Failure to successfully manage the airway is the most common cause of maternal death
Benefits: Speed of onset, secured airway, greater hemodynamic stability
Drawbacks: Risk of difficult mask ventilation/laryngoscopy/intubation, risk of aspiration, Potential MH, absence of maternal awareness, Neonatal respiratory and CNS depression
Describe aspiration prophylaxis for the pt scheduled for cesarean section.
Triple prophylaxis against aspiration
* Sodium citrate to neutralize gastric acid
*H2 receptor antagonist (ranitidine) to reduce gastric acid secretion
*Gastrokinetic agent (metoclopramide) to hasten gastric emptying and increase LES tone
When is the pregnant pt who presents for non-obstetric surgery at risk for aspiration?
At app. 18-20 weeks gestation, pregnant pts are considered “full stomachs”. Therefore, they require RSI with aspiration prophylaxis (this may be needed earlier if the pt has symptoms of GERD). These recommendations also apply to the immediate postpartum period. (note: one text says to consider a “full stomach” at 12 weeks; consensus is 18-20)
secure the airway with a 6.0 -7.0 ETT
Aspiration precautions:
* non-particulate antacid (sodium citrate) 15-30 mL within 15-30 min of induction
* H2 antagonist (ranitidine) 1hr before induction
* Gastric prokinetic agent (reglan) 1hr before induction
Use left uterine displacement in the second and third trimester
What is the risk of NSAIDs when used in pregnant pts?
Avoid NSAIDs after the first trimester, as they may close the ductus arteriosus
Compare and contrast the diagnostic criteria for gestational HTN, preeclampsia, and eclampsia.
The classic triad of preeclampsia consists of HTN that develops after 20 wks gestation, proteinuria. Generalized edema is no longer a diagnostic requirement.
Discuss the balance of prostacyclin and thromboxane in the pt with preeclampsia
The healthy placenta produces thromboxane and prostacyclin in equal amts. However, the pt with preeclampsia produces up to 7x more thromboxane than prostacyclin.
Increased thromboxane favors vasoconstriction, platelet aggregation, and a reduced placental blood flow
compare and contrast mild and sever preeclampsia
Discuss the use of magnesium for preeclampsia
The presence of seizures differentiates between preeclampsia and eclampsia
Seizure prophylaxis with magnesium sulfate:
* load: 4g loading dose over 10 minutes
* infusion: 1-2 g/hr
* Tx for mg toxicity: 10mL of 10% calcium gluconate IV
Detail anesthetic management for the patient with preeclampsia.
Anesthetic management for preeclampsia:
* fluid management is balanced between a volume contracted patient and a “leaky” vasculature from endothelial dysfunction.
* Neuraxial anesthesia assists with blood pressure control and also provides better uteroplacental perfusion
* be sure to rule out thrombocytopenia (<100,000) before performing a neuraxial block
* due to airway swelling, these pts have a higher incidence of difficult intubation’
* These pts have an exaggerated response to sympathomimetics and methergine.
* if they are receiving magnesium therapy, they will exhibit an increased sensitivity to neuromuscular blockers
* Magnesium relaxes the uterus and increases the risk of postpartum hemorrhage
what is HELLP syndrome? what is the definitive tx?
HELLP syndrome stands for: hemolysis, elevated liver enzymes, and low platelet count. It develops in 5-10% of those with preeclampsia. The pts experience epigastric pain and upper abdominal tenderness.
Like preeclampsia, the definitive tx for HELLP syndrome is delivery of the fetus
discuss the anesthetic considerations for maternal cocaine abuse.
Cocaine is an ester-type local anesthetic that inhibits NE reuptake in the presynaptic SNS neuron. Flooding the synaptic cleft with NE increases SNS tone
- CV risks include tachycardia, dysrhythmias, and myocardial ischemia.
- Acute intoxication increases MAC
- Chronic use decreases MAC
- OB risks include spontaneous abortion, premature labor, placental abruption and low APGAR scores
- HTN is probably best treated with vasodilators
- Beta-blockers can cause heart failure if the SVR is significantly elevated
- HoTN May not respond to ephedrine in chronic cocaine abusers ( D/t catecholamine depletion). Phenylephrine is best option.
- Chronic cocaine abuse is associated with thrombocytopenia (check platelet count before neuraxial anesthesia)
What is the difference between placenta accreta, increta, and percreta? What is the major risk that these complications present?
The placenta normally implants into the decidua of the endometrium. There are three types of abnormal placental implantations:
* Accreta: Attaches to the surface of the myometrium
* Increta: Invades the myometrium
* Percreta: Extends beyond the uterus
Uterine contractility is impaired, and there is potential for tremendous blood loss. Though neuraxial anesthesia is safe, GA is preferred
what is placenta previa? how does it present?
Placenta previa occurs when the placenta attaches to the lower uterine segment.
- It partially or completely covers the cervical OS
- Associated with PAINLESS vaginal bleeding
- Potential for hemorrhage
What conditions increase the risk of placenta previa?
The risk of placenta previa is associated with previous cesarean sections and a history of multiple births
what are the risk factors for placental abruption? how does it present?
Partial or complete separation of the placenta from the uterine wall prior to delivery. It results in hemorrhage and fetal hypoxia.
Risk factors include:
* PIH (pregnancy induced HTN)
* Preeclampsia
* Chronic HTN
* Cocaine use
* Smoking
* Excessive alcohol use
it presents with painful vaginal bleeding. Pain may be so severe as to cause breakthrough when epidural is in place.
What is the most common cause of postpartum hemorrhage? what are the risk factors?
Uterine atony is the most common cause. The risk of uterine atony is increased by:
* Multiparity
* multiple gestations
* Polyhydramnios (too much amniotic fluid)
* Prolonged oxytocin infusion prior to surgery
A pt suffers from retained placental fragments. What IV medication can you give to help with the extraction?
IV nitroglycerine provides uterine relaxation for placental extraction
What are the tx options for uterine atony?
- uterine massage
- oxytocin
- Ergot Alkaloids
- Intrauterine Balloon
What does Apgar score mean?
Used to assess the newborn and guide resuscitative efforts. Five parameters are evaluated at 1 and 5 minutes after delivery. The score at 1 minute correlates with fetal acid-base status, while the 5 minute score may be predictive of neurologic outcome.
* Normal: 8-10
* Moderate distress: 4-7
* impending demise: 0-3
know how to calculate apgar score
what is the best indicator of ventilation during neonatal resuscitation?
resolution of bradycardia is the best indicator of adequate ventilation
How do you dose epi and fluids during neonatal resuscitation?
Epi: 1:10,000 , 10-30 mcg/kg IV or 0.05-0.1mg/kg intrathecal
Volume expander: PRBCs, NS, LR 10mL/kg over 5-10 minutes
what are the normal vital signs for a newborn? how do they trend as the child ages?
Why is the neonate’s minute ventilation higher than the adult?
Oxygen consumption and carbon monoxide production are twice those of adults. Therefore, the neonate must increase alveolar ventilation accordingly.
It is metabolically more efficient to increase respiratory rate than it is to increase tidal volume. This explains why newborns have a higher RR, yet tidal volume is the same as the adult on a per weight basis (6mL/kg)
What is the primary determinant of BP in the neonate?
Heart rate is the primary determinant of cardiac output and systolic BP
BP= HR x SV x SVR
The neonatal myocardium lacks the contractile elements to significantly adjust contractility or stroke volume; the ventricle is noncompliant. Furthermore, the Frank-starling relationship is underdeveloped (but not entirely absent) in the newborn. Therefore, the heart rate must be maintained to ensure adequate tissue perfusion and oxygen delivery
Describe the autonomic influence on the newborns heart
Autonomic regulation of the heart is immature at birth, with the SNS being less mature than the PNS. Stressful situations, such as laryngoscopy or suctioning of the airway may cause bradycardia. Atropine may be administered prior to induction to mitigate this response.
Additionally, the baroreceptor reflex is poorly developed, so the reflex fails to increase heart rate in the setting of hypovolemia
Contrast the breathing pattern in adults and infants
Adult= mouth or nose
infant= preferential nose breather up to 5 months of age
- most infants convert to oral breathing if the nasal passages are obstructed
- B/L choanal atresia may require emergency airway management if the infant is unable to mouth breathe
Contrast the relative size of the tongue in adults and infants
adult= small relative to oral volume
Infant= large relative to oral volume
- the tongue is closer to the soft palate, which makes it more likely to obstruct the upper airway
- More difficult to displace during laryngoscopy
contrast the relative neck length in adults and infants
adult= longer
infant=shorter
* more acute angle required to visualize the glottis
contrast the epiglottis shape in the adults and infants
adults= leaf (C shape), floppier, short
Infant= U (omega shape), stiffer, longer
* A stiff epiglottis makes it more difficult to displace during laryngoscopy
Contrast the vocal cord position in adults and infants
Adult= perpendicular to trachea
Infant= anterior slant
* Visualization and passage of the ETT may be more difficult
* ETT may get stuck in the anterior commissure
Contrast the laryngeal position in the adults and infants
Adult= C5-C6
Infant= C3-C4
* Larynx more superior/cephalad/rostral but NOT anterior. The only time the infant’s airway is more “anterior” is during neck flexion
* Same position as the adult in age 5-6 yrs
Contrast the narrowest point of the airway in adults and infants
Adult= glottis (vocal cords)
Infant= cricoid or glottis
* resistance to ett insertion beyond the vocal cords is likely at the cricoid ring.
* cricoid tissue is prone to inflammation and edema formation -> stridor or obstruction
* Poiseuille’s law- small changes in radius can significantly increase resistance to airflow (radius to the 4th power of laminar flow)
Contrast the orientation of the right mainstem bronchus in adults and infants
Adult: more vertical
Infant: less vertical
* up to age 3 year, both bronchi take off at 55 degrees.
* In the adult the right bronchus takes off at 25 degrees and the left at 45 degrees
Contrast the oxygen consumption, Alveolar ventilation, respiratory rate, tidal volume in the neonates and adults
Because the neonatal alveolar surface area is only 1/3 of the adult and oxygen consumption is twice that of the adult, the neonate must increase alveolar ventilation in order to sustain normal arterial gas tensions.
It is metabolically more efficient for the neonate to increase respiratory rate than it is to increase tidal volume.
Why do neonates desaturate faster than adults?
Neonates have a/an:
* Increased oxygen consumption to support metabolic demand
* Increase alveolar ventilation to increase oxygen supply.
* Slightly decreased FRC reflects a reduced oxygen reserve.
The net result is that the neonate has an increased ratio of alveolar ventilation relative to the size of its FRC. A faster gas turnover means that the 02 supply in the FRC is quickly exhausted during apnea.
Why is inhalation induction faster with neonates than with adults?
The increase ratio of alveolar ventilation relative to the size of the FRC explains a quicker inhalation induction for neonates.
A faster turn over of the FRC (fewer alveoli need to achieve steady state) allow a speedier development of anesthetic partial pressure inside the alveoli and consequently a more rapid change in the anesthetic partial pressure inside the brain and spinal cord.
What is the difference between fast and slow twitch muscle fibers? how does this relate to new natal pulmonary mechanics?
The diaphragm in intercostal muscles are composed of two types of muscle fiber:
* Type1= Slow-twitch muscle fibers are built for endurance-they are resistant to fatigue.
* Type2- fast-twitch Muscle fibers that are built for short bursts of heavy work-they tire easily.
A smaller number of type one, slow twitch and Durant’s muscle fibers within the diaphragm increases the neonates risk for respiratory fatigue and developing respiratory failure.
Compare and contrast neonates to adults in terms of FRC, VC, TLC, RV, CC, and VT.
How does the newborn’s ABG change from delivery to the 1st 24 hours of life?
How does hypoximia affect ventilation in the newborn?
Respiratory control doesn’t mature until 42-44 week.
* before maturation: hypoxemia depresses ventilation
* after maturation: hypoxemia stimulates ventilation
What is the P50 for fetal hemoglobin? Why is it important?
Fetal hemoglobin HGB F has a P50 of 19mmHg.
* hgb F shifts the curve to the left (latch)
* It benefits the fetus by creating an oxygen partial pressure gradient across the uteroplacental membrane that facilitates the passage of 02 from the mother to the fetus.
Why does Hgb F have a higher affinity for oxygen?
Adult hemoglobin hgb A consists of two alpha and two beta chains, While fetal hemoglobin has 2 alpha and 2 gamma chains.
We know that 2,3-DPG causes a right shift in the oxyhemaglobin dissociation curve, but you may not know that the binding site for 2,3-DPG is only on the Beta chain. Since hemaglobin F has 2 gamma instead of to Beta chains it does not bind 2,3-DPG. This shifts the curve to the left and explains why hemoglobin F has a higher affinity for oxygen.
What are indications for ffp transfusion in the new neonates?
The indications for transfusion of FFP mirror the recommendations set forth by the ASA guidelines. These include.
* Emergency reversal of warfarin
* Correction of coagulopathic bleeding with increased PT > 1.5 or increased PTT.
* Correction of coagulopathic bleeding if > 1 blood volume has been replaced and coagulation studies are not easily obtained.
FFP is NOT indicated for expansion of intravascular volume.
What is the dose for FFP transfusion in neonates?
Dose=10 - 20 ml/kilogram.
When is platelet transfusion indicated in the neonate? What is the dose?
Platelet transfusion is recommended for invasive procedures to maintain a platelet count above 50,000.
* dose if obtained from apheresis=5mL/kg
*Dose if pooled platelet concenteation = 1pack/10kg
Describe the physiologic changes that occur as a result of massive transfusion.
A massive transfusion is associated with:
* alkalosus-> Due to citrate metabolism to bicarbonate in the liver.
* hypothermia-> Due to transfusion of cold blood
* Hyperglycemia -> Due to dextrose additive to stored blood.
* hypocalcemia-> Due to the binding of calcium by citrate.
* hyperkalemia-> Due to the administration of older blood.
When RBC’s are stored, the cell membrane becomes dysfunctional, which allows potassium to leak into the supernatant. Administration of PRBC’s to neonates can lead to hyperkalemia and cardiac arrest. The risk is reduced by administering washed or fresh cells that are less than 7 days old.
What is the estimated blood volume in the premature neonate, term neonate, infant, child> one year?
A 3 kg term neonate requires emergency exploratory laparotomy for necrotizing enterocolitis. Her preoperative hematocrit is 50% .What is the maximum allowable blood loss to maintain a hematocrit of 40%?
Maximum ABL= EBV x (HCT starting- HCT Target)/ HCT starting
- EBV= 3kg x 80 to 100mL/kg (Premature vs neonate) = 240mL
- HCT-starting - HCT target = 50-40=10
- Mabl= 240 to 300mL x (50-40)/50= 48- 50mL
When do GFR And renal tubular function achieve full maturation?
Normal GFR is reached at 8 to 24 months of age.
* Before maturation, neonates do a poor job conserving water, so they are intolerant of fluid restriction. On the flip side, they are unable to excrete large volumes of water, so they do not do well with fluid overload either.
Normal tubular function is reached at 2 years of age.
In the 1st days of life, the neonate is an obligate sodium loser. After that, she is better able to retain sodium than excrete it. She also has a tendency to lose glucose to the urine.
Compare contrast the distribution of body water in the premature neonate, neonate, child and adult.
What signs suggest dehydration in the neonate?
Signs of dehydration:
Sunken anterior fontanel
Weight loss a 10% reduction in the 1st week is normal.
Irritability and lethargy.
Dry mucus membranes.
Absence of tears
Decrease skin turgor
Increased hematocrit in the absence of transfusion.
Describe the 4:2:1 rule of fluid management.
Step 1: 0-10kg-> begin with 4mL/kg/hr
Step2: 10-20kg-> add 2mL/kg/hr to previous total
Step3: >20kg -> add 1 mL/kg/hr to the previous total
If the pt is > 20kg, then you can uae the shortcut -> pts weight in kg+40
How should the NPO fluid deficit be replaced?
Multiply the patients hourly fluid maintenance rate by the number of hours of NPO time period replace this deficit over 3 hours.
1st hr: 50%
2nd hr: 25%
3rd hr: 25%
How should 3rd space losses be replaced in the neonates?
Replace fluid loss to third spacing and evaporation.
Minimal surgical trauma = 3-4 mL/kg/hr
Moderate surgical trauma = 5-6 mL/kg/hr
Major= 7-10mL/kg/hr
As a general rule, 3rd space loss is not included in the 1st hour of anesthesia.
Describe the 5 types of tracheoesophageal atresia. which is the most common?
Esophageal atresia is the most common congenital defect of the esophagus, and most of these children also have a tracheoesophageal fistula.
Type C accounts for around 90% of all TEFs
In this configuration, the upper esophagus ends in a blind pouch, and the lower esophagus communicates with the distal trachea.
The patient has a hernia at the foramen of Bochdalek. Which congenital condition does this patient have?
Congenital diaphragmatic hernia is a diaphragmatic defect that allows the abdominal contents to enter the thoracic cavity.
*The foramen a Bochdalek is the most common sight of herniation (usually on the left side).
* Other sites herniation include the foramen of Morgagni and around the esophagus.
Compare and contrast omphalocele and gastroschisis
what conditions affect PVR and SVR? how?
successful management of shunt lesions necessitates a solid understanding of the factors that affect PVR and SVR. know this table!
What are the hemodyanmic goals for tetralogy of Fallot?
Discuss the typical ages affected and speed of onset for epiglottitis (Supraglottits) and croup (laryngotracheobronchitis) .
A pt with a respiratory infection presents for a tonsillectomy. Which signs and symptoms favor postponing procedure?
Which syndromes are associated with difficult airway management?
why does residual volume increase in the elderly? what are the consequences of this?
The aged lung has a reduced elastic recoil, which causes it to become overfilled with gas. This process increases residual volume, which explains why the FRC increases as we age.
- closing capacity surpasses FRC at around 45 years old in the supine position and around 65 years old when standing.
*when CC> FRC, the small airways collapse during tidal breathing. This contributes to V/Q mismatch, increased anatomic dead space, and a reduction in PaO2
