2nd and 3rd Trimester Bleeding

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  • Placenta previa - when the placenta partially or totally covers the internal cervical os. Defined as edge of placenta <10 mm from internal cervical os 

    • Occurs approximately 4/1000 births, but varies world wide. Increased risk associated with history of previous placenta previa, previous C-section, and multiple gestation 

    • Approximately 90% of placenta previa identified on ultrasound <20 weeks → resolve before delivery 

    • Painless vaginal bleeding can occur up to 90% of persistent cases 

    • 10-20% of women present with uterine contractions, pain, and bleeding 

    • Why we care: can lead to catastrophic bleeding, need for transfusion, and delivery. Can lead to stillbirth  

  • Placenta accreta spectrum 

  • Vasa previa 

    • What it is: when fetal vessels run within the membranes over the internal os of the cervix 

    • Very rare. Has been quoted 1/2500 deliveries 

    • Painless bleeding usually 

    • Two types: 

      • Velamentous cord insertion and fetal vessels that run freely within the amniotic membranes overlying the cervix or in close proximity of it (2 cm from os); usually pregnancies with low lying placenta or resolved placenta previas are at risk 

      • Succenturiate lobe or multilobe placenta and fetal vessels connectin both lobes course over or in close proximity of cervix (2 cm from os)   

    • Other risks: IVF 

    • Why we care: increased risk of fetal hemorrhage, exsanguination, and death 

  • Placental abruption

    • What it is: Separation of the placenta from the inner wall of the uterus before birth 

    • Usually painful bleeding 

    • Incidence: 2-10/1000 births in the US 

    • Risk factors: hx of fabruption, cocaine use, tobacco use, hypertension, uterine abnormalities (ie. fibroids, bicornuate uterus) 

    • Why we care: can lead to catastrophic bleeding, need for transfusion, and delivery. Can lead to stillbirth. 

  • Uterine rupture 

    • What it is: significant uterine disruption. Usually will occur along a previous uterine scar 

    • Very painful bleeding (pain is usually more significant than bleeding) 

    • Risk factors: previous uterine rupture, previous uterine scar, especially if a fundal or vertical scar (ie. cesarean delivery, myomectomy), induction, labor 

    • Why we care: very high incidence of morbidity and mortality for both mom and baby 

  • Less dangerous causes:

    • Labor - “bloody show” with labor

    • Cervicitis 

      • Can be caused by infection (ie. BV, candida infection, trichomonas, chlamydia, gonorrhea) 

    • Cervical polyp 

    • Vaginal laceration 

Doing a Workup for Bleeding in the 2nd and 3rd Trimester

  • History 

    • How much bleeding? (soaking through clothes? Passing clots?)

      • Passing tissue? 

      • Remember: just because someone has light bleeding does not mean that they don’t have something life-threatening for them or their fetus   

    • Is there pain? 

    • How long has the bleeding been happening? 

  • Exam 

    • After your physical exam, do an abdominal and pelvic exam 

      • Lift the sheet: how fast is the patient bleeding? 

      • Abdominal exam: is there tenderness to palpation anywhere? Over the uterus? How pregnant does the patient appear to be (if no records?) 

        • Patients with rupture will be very tender to palpation 

        • Less likely to be tender to palpation with something like placenta or vasa previa 

      • Start with a speculum exam - if passing tissue, that should be sent to pathology 

        • Look for vaginal laceration, neoplasms, discharge, evidence of cervicitis, cervical polyps, fibroids, ectropion 

        • Send testing for cervicitis and vaginitis (ie. wet mount, as well as chlamydia/gonorrhea) 

      • Do not do a digital cervical exam without confirming where the placenta is located!

  • Labs and Imaging 

    • Pregnancy test if not confirmed (just a urine pregnancy test!) 

    • Type and screen, CBC, coagulation profile

    • Putting the baby on the monitor 

      • Consider doing so if the fetus is viable 

      • Sometimes, the only way to tell if someone is abrupting or rupturing their uterus (other than having abdominal pain) is seeing non-reassuring fetal heart tracing 

      • Watch contraction pattern - can discern if someone is contracting with bleeding or now. Also, there may be evidence of abruption on monitor (small amplitude, frequent contractions) 

    • Ultrasound 

      • Usually, transabdominal is enough, but if you think that there is a placenta previa, placenta accreta, or vasa previa, you should do a transvaginal ultrasound 

      • Color and pulsed Doppler should be used to help in diagnosis 

      • Remember that placental abruption is a clinical diagnosis: you may not always see a blood clot or an area that appears “abrupted” on the placenta

      • Usually, placenta previa, placenta accreta, and vasa previa are diagnosed at the mid-trimester ultrasound and will require clinical follow-up 

Management 

  • Depending on the amount of bleeding: 

    • Vital signs 

    • Two large bore IVs 

    • Resuscitation - fluids vs. blood products

  • If there is less bleeding and you think you have more time:

    • Blood type and Rh status - administer Rhogam if it is indicated 

    • Management otherwise depends on reason for bleeding - will discuss briefly some of the more dangerous things 

  • Placenta previa:

    • Usually will trigger an admission for monitoring 

    • If preterm, usually recommend steroids, and if <32 weeks, can discuss magnesium for CP prophylaxis 

    • Pending the stability of mom and fetus, may require emergent delivery via cesarean section 

    • Certain locations may have a “threshold” for prolonged admission - ie. three strikes = three bleeds and admission for the rest of pregnancy 

    • If otherwise stable, can usually be delivered between 36w0d - 37w6d via c-section

    • Usually can have vaginal delivery if >2 cm from os, but some institutions may discuss if >1 cm 

  • Placenta accreta spectrum:

    • Will usually also trigger an admission for monitoring, and can also lead to emergent delivery + hysterectomy pending stability 

    • Steroids and mag if indicated 

    • If stable, recommend delivery between 34w0d-35w6d, and usually this will be done at tertiary care center with multi-disciplinary team 

  • Vasa previa:

    • There is usually a lower threshold for bleeding and contraction in vasa previa because the bleeding could come from the fetus 

    • While an adult human has 5-6L of blood, a fetus has much less. A term fetus+placenta can have up to 500mL of blood (baby may have 250-300cc). Usually describe to patients in measurements of a soda can (355 mL). 

    • For this reason, many places will hospitalize vasa previa between 28-34w0d and monitor 

    • Recommend delivery between 34w0d-37w0d pending stability of mom and baby 

Tobacco Use in Pregnancy

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Tobacco remains the leading cause of preventable disease, disability, and death in the USA, despite overall decreasing rates of smoking!

  • 14% of US adults smoke cigarettes. This rate is lower in pregnancy, around 7.2%; however, young women are a high risk group for cigarette smoking compared to the general population.

  • Tobacco use in pregnancy specifically is linked to higher risk of:

    • Ectopic pregnancies

    • Cleft lip/palate

    • Fetal growth restriction and low birth weight (13-19% of term infants with tobacco exposures)

    • Placenta previa

    • Placental abruption

    • PPROM

    • Preterm delivery (5-8% attributable risk)

    • Increased perinatal mortality (5-7% attributable risk)

    • Increased risk of sudden infant death syndrome (22-34% attributable risk)

  • Tobacco use also has lifelong health implications!

    • Pregnancy can be a great motivator to quit smoking and make significant changes for lifelong health -- 54% of those who smoke during/pre-pregnancy will quit at least for pregnancy!

  • Data regarding e-cigarettes/vaping, cigars, and hookah are limited, though are also risky.

    • However, these may have somewhat different risks, though many (particularly hookah and vaping) are perceived to be safer -- they are not!

    • The CO 807 has a great table comparing amounts of nicotine in each varying method of consumption -- worth keeping handy when you’re looking to prescribe/suggest replacement therapy:

ACOG CO 807

How do I intervene as a clinician?

  • Ask!

    • Be sure to ask about alternative forms of nicotine consumption as well -- patients may not disclose vaping/hookah/etc. Use unless specifically asked. 

  • Use motivational interviewing techniques

    • Cognitive behavioral therapy and motivational interviewing are beneficial to initiate and sustain tobacco use cessation.

    • Even if not ready to quit, consistent motivational approaches may be beneficial over time.

  • You can use a tool, like the 5As:

    • Ask -- characterizing use at the same time

    • Advise -- if still using, provide advice about risks of continued use

    • Assess -- whether patient is willing to quit. This can be continued with motivational strategy at future visits if not ready at the first.

    • Assist -- if ready to quit, provide materials and options to help get the quit started. Suggest importance of having a tobacco-free space at home, seeking out a “quitting buddy,” and/or using a service like 1-800-QUIT-NOW to provide ongoing support.

    • Arrange -- continue follow up visits to track/encourage success 

  • 50-60% of those who quit smoking during pregnancy will resume within 1 year postpartum.

    • Keep up and continue to ask at future visits.

    • Encourage whole family to quit smoking as well to have family-motivated success.

Pharmacotherapy for tobacco cessation

  • If used during pregnancy, note data is limited for most methods. 

  • Nicotine replacement:

    • Provide a stable, controlled dose of nicotine in the form of gums, patches, or lozenges

      • Gums may provide some benefit psychologically due to oral fixation

    • Have not been demonstrated to be effective in pregnancy, unfortunately.

      • Any planned use should be with clear resolve of patient to quit in mind, as these methods still deliberately expose maternal-fetal dyad to nicotine and likely some continued form of risk.

  • Pharmacologic cessation agents

    • Varencicline (Chantix)

      • Dose pack to start therapy.

      • Partial agonist for nicotinic receptors in brain

      • Limited data in pregnancy, but that which exists does not demonstrate teratogenicity.

    • Bupropion (Wellbutrin)

      • Most studies have looked at a dose of 150mg BID for 7-12 weeks.

      • Antidepressant

      • Also limited data in pregnancy, but no known risk of fetal anomalies or adverse pregnancy outcomes.

Delayed Umbilical Cord Clamping

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Reading: CO 814 https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2020/12/delayed-umbilical-cord-clamping-after-birth 

Delayed Cord Clamping - An Overview

  • Small studies initially demonstrated 80-100cc of blood transferring from the placenta to the newborn within 3 minutes after birth, and

  • 90% of that blood volume transfer is achieved within just a few breaths in healthy term infants.

    • A 3kg infant (6lb 10oz) has a typical blood volume of around 250 cc… so the difference is potentially huge!

  • Modern studies of “delayed” cord clamping is usually defined as 30-60 seconds of delay after birth to clamp the cord, and shows benefits for both term and preterm infants.

  • For term babies:

    • Improved hemoglobin levels

    • Improved iron stores (lasting even to a few months of life) → potentially favorable neurodevelopmental outcomes

  • For preterm babies:

    • Reduced rates of IVH and NEC

    • Lower risk of transfusion

  • Basically for these reasons, most organizations across the world recommend 30-60 seconds of DCC for most term and preterm infants, though the range ca be up to 5 minutes (ACNM). 

    • ACOG specifically recommends 30-60 seconds of DCC for vigorous term and preterm infants. 

  • Are there concerns? Theoretically, yes:

    • Perhaps delayed cord clamping delays resuscitation for babies who need it?

      • Sick/preterm babies may actually benefit from placental transfusion as the placenta continues gas exchange after delivery while still attached!

    • Maybe delayed cord clamping causes polycythemia or jaundice?

      • No solid evidence of this in preterm infants

      • Perhaps some evidence in term infants, but slight.

What’s the evidence?

  • Studies of Doppler sonography during DCC have demonstrated marked increase of placental transfusion during those breaths.

    • The extra iron load provided by DCC here has been shown to reduce/prevent iron deficiency through 1 year of life.

    • Iron deficiency has been linked to cognitive, motor, and behavioral developmental delays that may be irreversible.

      • Iron deficiency is definitely prevalent in low-income countries, but also common in higher income countries too! (5-25%)

    • Additionally, that blood and plasma volume will transfuse over immunoglobulins and stem cells, which may be of particular benefit to preterm babies.

  • In preterm infants:

    • Systematic review of 15 trials of 738 infants demonstrates DCC over immediate clamping leads to:

      • Fewer transfusions for anemia (RR 0.61)

      • Lower risk of IVH (all grades, sonographic dx) (RR 0.59)

      • Lower risk of NEC (RR 0.62)

  • In term infants:

    • Systematic review of 15 trials involving 3911 women and their singleton infants:

      • DCC had higher immediate hemoglobin levels (2.17 g/dL difference) and to 24-48h after birth (1.49 g/dL)

      • At age 3-6 months, immediate clamping had a RR of 2.65 for iron deficiency!

      • NO difference in rates of polycythemia or jaundice, but jaundice requiring phototherapy was slightly higher risk for DCC (2.74% vs 4.36%, RR 0.62).

      • Neurodevelopmental outcomes limited, but no difference versus slight benefit to DCC over ICC. 

        • Overall, seems to be beneficial for babies, at least in the immediate term, with more definite benefit for preterm infants.

  • What about maternal risks?

    • Five trials of over 2200 women did not demonstrate any increased risk of PPH, estimated blood loss, difference in hemoglobin level, or risk of transfusion -- even at cesarean!

      • ACOG does caution though that with previa/abruption or other situations for high increased risk of hemorrhage, benefit versus risks of DCC should be weighed.

Can I screw it up?

In a word, yes. Here are some tips:

  • Newborn care should proceed as usual.

    • Dry and stimulate for the first breath/cry, maintain normothermia with skin-to-skin contact.

      • Positioning on the chest/abdomen (versus holding infant at level of introitus or lower) doesn’t seem to have an effect on the amount of blood transfused.

    • Clear secretions only if copious or obstructing the airway.

    • Even with meconium, DCC can continue as long as infant is vigorous.

  • Continue with active management of 3rd stage.

    • Use uterotonics (oxytocin at this point, typically) to minimize bleeding

  • Use common sense on when to not use DCC.

    • If maternal hemodynamic or neonatal stability is of concern, then DCC should not be continued.

  • If you need/plan to get umbilical cord gases:

    • Studies are mixed here. A definitive study would be nice, if you’ve got some funding opportunities around you!

  • Milking the cord -- don’t do it!

    • It seems to make some sense -- if we push blood faster through the cord, we get the transfusion benefit of DCC in less time -- perhaps some use for the infant in need of resuscitation or extreme prematurity?

      • A recent study of infants undergoing milking at extreme prematurity (23-27 weeks) was halted early due to higher risk of IVH in the milking group compared to DCC.

        • ACOG recommends not milking at under 28 weeks gestation.

      • Prior studies to this including infants of later gestational ages, that showed some potential benefit to hemoglobin levels, but were overall mixed. ACOG interprets this as no definitive evidence for milking at greater that 32 weeks -- but we’d recommend against it at this point, given the pretty definitive risk of harm for premature infants at least.

  • If patient desires cord blood banking… reconsider.

    • Cord blood banking success is significantly decreased when there is a 60 second delay in DCC.

    • Families considering banking should be aware of this risk… 

      • It’s arguable that DCC may have more benefits than cord blood banking. 

Anemia in Pregnancy

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Be sure to check out the new ACOG Practice Bulletin #233 on anemia — first time it’s been updated in a while! And while you’re at it, check out our old episode on sickle cell anemia.

Physiologic Changes in Pregnancy to Blood Volume 

  • Definitions

    • Remember that anemia in pregnancy is defined as: 

      • Hgb <11 g/dL in the first and third trimester 

      • Hgb <10.5 g/dL in the second trimester 

      • Previously, ACOG had discussed a lower threshold for certain people based on race, but one important study found that this lower threshold likely contributes to the perpetuation of racial disparities in medicine without a scientific reason for lower Hgb 

  • What happens in pregnancy? 

    • Physiologic

      • Plasma volume expands by 40-50%

      • Erythrocyte mass expands by 15-25% 

      • So even though there is increased red cell mass, it seems overall that HCT % goes down 

    • There is also increased iron requirement, so it is more likely for people to become iron deficient 

Causes of Anemia in Pregnancy 

  • Acquired 

    • Deficiency 

      • Iron deficiency - by far the most common 

      • B12 deficiency 

      • Folic acid deficiency 

    • Hemorrhagic 

    • Anemia of chronic disease 

    • Acquired hemolytic anemia 

    • Aplastic anemia 

  • Inherited 

    • Thalassemias 

    • Sickle cell 

    • Hemoglobinopathies 

    • Inherited hemolytic anemias 

Work-up of Anemia in Pregnancy 

  • Screening 

    • All pregnant people should be screened for anemia with CBC in the first trimester and again right before third trimester (usually 24-28 weeks) 

    • Also, should have discussion with everyone about screening for hemoglobinopathies if they have not been screened before 

  • Work up of asymptomatic with mild to moderate anemia: 

    • Anemia type: microcytic vs normocytic vs macrocytic 

      • Microcytic (MCV < 80 fl) 

        • Most commonly: iron deficiency 

        • But can also be caused by thalassemias, anemia of chronic disease, sideroblastic anemia, etc. 

      • Normocytic (MCV 80-100fL) 

        • Hemorrhagic or early iron deficiency = common 

        • Others: anemia of chronic disease, bone marrow suppression, chronic renal insufficiency, hemolytic anemia 

      • Macrocytic (MCV > 100 fL) 

        • Folic acid deficiency, B12 deficiency = most common 

        • Others: Reticulocytosis, liver disease, alcohol abuse, drug-induced hemolytic anemia 

  • Iron studies with measurement of red blood cell indices, serum iron levels, ferritin levels 

    • Some places also include a total iron-binding capacity 

    • In someone with iron deficiency, iron levels and ferritin will be low, while TIBC will be high 

  • Peripheral blood smear 

  • Can also look at vitamin B12 and folate levels if macrocytic 

  • Other work-up: 

    • If not responding to treatment with iron, folate, or B12, then further workup should be done 

    • Ie. is there a reason for malabsorption (gastric bypass?) 

    • Is there a reason for blood loss? 

Treatment of Anemia in Pregnancy 

  • Iron deficiency 

    • Can start with oral iron, unless there is a reason for malabsorption 

      • Usual requirements: 27 mg daily during pregnancy, and usual diet will live 15 mg of elemental iron/day 

      • Most oral forms of iron will exceed this 

      • If unable to tolerate oral iron or has reasons for malabsorption, can do IV iron, which can come in the form of iron dextran, ferric gluconate, or iron sucrose 

  • Folate or B12 deficiency

    •  MCV > 115 is almost exclusively seen in people with folate or B12 deficiency 

    • Give folate or B12! 

    • Folic acid: 400 mcg/day unless there are other indications for increased folate (ie. history of neural tube defect affecting child, on anti-epileptics) 

    • B12: usually only seen in people with gastric resection or Crohn disease 

      • Usually given IM every month, 1000 mcg/injection 

  • Other causes 

    • Depending on the cause, may need to work with colleagues from other specialties 

    • Or your friendly neighborhood MFM 

  • A word on transfusion 

    • Hgb <6 g/dL have been associated with abnormal fetal oxygenation 

    • Usually recommend transfusion if Hgb <7 or if symptomatic 

    • However, can consider higher threshold if other co-morbidites (ie. sickle cell anemia with known crises if Hgb <7) 

Laparoscopy IV: Pneumoperitoneum

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We’re back today with Dr. Ruhotina and the next piece in our laparoscopy series. Today we’re talking all about gas and pneumoperitoneum. As before, Dr. Ruhotina made some awesome notes — take a look below!

Pneumoperitoneum Physiology 

-        Laparoscopic surgery involves insufflation of a gas (usually carbon dioxide) into the peritoneal cavity producing a pneumoperitoneum

-        Causes an increase in intra-abdominal pressure (IAP)

-        Insufflated at a rate of 4-6 L/Min to a pressure of 10-20mmHg

-        The pressure is maintained by a constant gas flow of 200-400 ml/min

Cardiovascular effects

-        Increased IAP affects venous return, systemic vascular resistance and myocardial function 

-        Increases in IAP result in compression of the vena cava decrease venous return decrease cardiac output 

-        Systemic vascular resistance is increase because of direct effects of IAP (+ increased circulating catecholamines)

o   The SVR change is usually greater than the reduction in cardiac output results in maintaining or even increasing systemic blood pressure

-        Increase SVR, systolic and diastolic pressures and tachycardia increased myocardial work load 

-        If IAP increases further decrease cardiac output further  decrease blood pressure 

Respiratory 

-        Supine position and general anesthesia decrease functional residual capacity 

-        Pneumoperitoneum + Trendelenburg cephalad shift of diaphragm further decrease FRC 

o   Can lead to atelectasis, ventilation-perfusion mismatch, potential hypoxemia, and hypercarbia 

Renal  Increased IAP increased renal vascular resistance and reduction in GFR decreased function and urine output 

 

GI Increased IAP can potential lead to regurgitation of gastric content with increased risk of pulmonary aspiration 

 

Neurological Rise in IAP increased intracranial pressure may result in decreased cerebral perfusion pressure 

 

Effects of gas absorption

-        CO2 most frequently used gas for insufflation colourless, nontoxic, nonflammable and has the greatest margin of safety in the event of a venous embolus since it is rapidly absorbed from the peritoneal cavity, additionally the  metabolic end products easily exhaled through the pulmonary alveoli. 

-        Alternatives to CO2: NO, Air, Helium, Argon

o   NO: Benefits: less acid-base disturbance, may be better for severe cardiopul disease, less post op pain, Risks: supports combustion, not flammable itself only when combustible gas present hydrogen or methane seen with bowel perforation

o   Argon/Helium(inert gases): avoids complications of hypercarbia or acidosis, although decreased solubility in blood therefore increased risk of extraperitoneal gas extravasation such as gas embolus, more expensive 

-        CO2 gas can be administered cold or heated, with or without humidification.

o   Compared with cold gas, heated gas led to only a minimal, clinically insignificant rise in core body temperature of 0.31° Celsius (95% CI 0.09-0.53), without any meaningful improvement in patient outcomes or ease of surgery extra cost of heating and/or humidifying gas used in laparoscopy cannot be justified, according to a Cochrane review of 22 randomized trials

-        Absorbed readily from peritoneum causing increase in PaCO2  increasing cardiac contractility and reduction in diastolic filling which can result in decreased myocardial oxygen supply to demand ratio and greater risk of myocardial ischemia 

-        Arrythmias  nodal rhythm, sinus bradycardia and asystole attributed to vagal stimulation that can be initiated by stretching the peritoneum 

o   Can see this effect more pronounced at the beginning of insufflation 

-        Subcutaneous emphysema, pneumomediastinum and pneumothorax

o   May occur because of incorrect positioning of the gas insufflation needle or trocars or by gas dissecting across weak tissue planes attributed to increased abdominal pressure

-        Venous gas embolism

o   Rare but fatal complication

o   May occur if carbon dioxide is insufflated directly into a blood vessel or by gas being drawn into an open vessel 

o   The physiological effect caused by CO2 are less than that with air because of its greater solubility 

o   However you can see hypotension, desaturation, and mill wheel murmur 

o   Treatment rapid deflation of the abdomen and resuscitation, place in left lateral position and the air aspirated from the central line 

 

Indicators on insufflator machines: 

Important readings of insufflator.

  • Preset Insufflation pressure,

  • Actual Pressure

  • Gas flow rate and

  • Volume of gas consumed

 

Preset Pressure

-        Pressure adjusted by surgeon before starting insufflation

-        The preset pressure ideally should be 12 mmhg- 15mmhg

-        Fifteen mmHg is used as the standard insufflation pressure. 

o   multiple reasons for the use of a 15 mmHg threshold most importantly it is a function of basic cardiovascular physiology

o   Elevated IAP exerts its effects primarily on the cardiovascular system and secondarily on the pulmonary and renal systems. It is well known that the cardiopulmonary, renal and abdominal affects are minimal and still reversible at an insufflation pressure of less then or equal to 15mmHg

o   Animal studies have shown that an intra-abdominal pressures of 20 mmHg has the following effects:

§  markedly impairs renal function, reducing GFR and RBF to 21% and 23% of their baseline values

§  Adverse cardiac and pulmonary effects for prolonged intra-abdominal pressures of 20mmHg lasting over three hours

§  Brief increases to a pressure of 20mm are tolerable

-        Whenever intra abdominal pressure decreases due to leak of gas outside, insufflator eject some gas inside to maintain the pressure equal to preset pressure and if intra-abdominal pressure increases due to external pressure, insufflator sucks some gas from abdominal cavity to again maintain the pressure to preset pressure.

 

Actual Pressure

-        Actual intra-abdominal pressure sensed by insufflator

-        With veress needle is attached there is some error in actual pressure reading because of resistance of flow of gas through small caliber of veress needle. Many microprocessor controlled good quality insufflator deliver pulsatile flow of gas when veress needle is connected, in which the low reading of actual pressure measures the true intra-abdominal pressure.

-        If there is any major gas leak actual pressure will be less and insufflator will try to maintain the pressure by ejecting gas through its full capacity.

 

Flow rate

-        Rate of flow of CO2 though the tubing of insufflator

-        Some information suggests that when you attach the veress needle the flow rate should be adjusted for 1 liter per minute. 

o   Experiment were performed on animals where direct I.V. CO2 were administered and it was found that risk of air embolism is less if rate is within 1 liter/minute.

o   At the time of access using veress needle technique sometime veress needle may be inadvertently enter inside a vessel but if the flow rate is 1 liter/minute there is less chance of serious complication

-        When initial pneumoperitoneum is achieved and canulla is inside abdominal cavity the insufflators flow rate may be set at maximum

 

Total Gas used

-        Fourth indicator of insufflator

-        Normal size human abdominal cavity need 1.5 liter CO2 to achieve intra-abdominal actual pressure of 12 mm Hg. In some big size abdominal cavity and in multipara patients sometime we need 3 liter of CO2 (rarely 5 to 6 liters) to get desired pressure of 12mm Hg. Whenever there is less or more amount of gas is used to inflate a normal abdominal cavity, surgeon should suspect some error in pneumoperitoneum technique. These errors may be leak or may be pre-peritoneal space creation or extravasations of gas.

 

Prior to starting your case: 

-        Turn the insufflator on and check the carbon dioxide (CO2) cylinder to make sure it contains sufficient gas to complete the procedure

o   Have extra CO2 container in room if needed

-        Check the insufflator to assure it is functioning properly

o   After  connecting sterile insufflation tubing  Turn the insufflator to high flow the actual pressure indicator should register 0 

o   Kink the tubing to shut off the flow of gas The pressure indicator should rapidly rise to 30mmHg and flow indicator should go to zero (Fig. 2.2). The pressure/flow shutoff mechanism is essential to the performance of safe laparoscopy. These simple checks verify that it is operating properly. 

 

Closed entry abdominal technique opening abdominal pressure

-        several prospective studies have demonstrated that the initial intra- abdominal pressure (IAP) 8 mmHg provides a reliable confirmation of appropriate Veress needle tip placement through the umbilicus or Palmer’s point [48–50]. 

o   In obese women IAP may be higher than in non-obese women, and can be up to 10 mmHg when the Veress needle is correctly inserted. 

 

TROUBLESHOOTING 

  • Loss of working space → ACTUAL PRESSURE HIGHER THAN SET PRESSURE, FLOW RATE = 0

    • Check actual and set pressure of pneumoperitoneum

    • Check status of relaxation of the patient (look for intraabdominal muscle contractions or firmness of abdomen, this is different than anesthesia checking neuromuscular twitch as diaphragm relaxation is different than intraabdominal)

    • Check valve on for connection insufflator tubing

    • Check insufflator tubing along the entire path, make sure it is not kinked

    • Mechanical obstruction- kinking of tubing, someone standing on tubing, closed valve 

  • Loss of working space→ ACTUAL PRESSURE LOWER THAN SET PRESSURE, FLOW RATE= HIGH indicates a leak 

    • Check insufflator tubing to make sure tubing is connected to insufflator and port

    • Check all ports and make sure the valves are closed

    • Check all ports for leaking co2 

    • Check for distention of bowel and bladder catheter as CO2 can escape into hollow organ (bladder or bowel)

  • Loss of working space→ ACTUAL PRESSURE IS LOWER THAN SET PRESSURE, FLOW RATE=0 (no flow)

    • Ensure power is on 

    • Check tank gas level

  • If screen blank

    • Most likely = disconnected power cords, disconnected cables, blown light source, disconnected light cable