Ethan frome

Problem Based Learning Scenarios For
Obstetric Anaesthesia
Basic Scenarios 1 to 5
Scenario 1(basic) PRMH 2004 - tick box when completed
You are the duty anaesthetist in the labour suite and have been informed by a midwife
that “the lady in room 6 needs an epidural”. From the board you can see that the lady in
question is a p1+0 24 yr old at 5cm.
What further information are you looking to glean from casenotes/midwife/patient? You are satisfied that there are no contraindications. The lady is in obvious distress with
each contraction, and has had an epidural during her previous labour.
How do you consent this lady? What risks do you tell her about? What are your views on consent in this setting? You begin preparations for the epidural
Describe in detail your technique. Justify what you do as far as possible. You elect to use a low dose 0.1% bupivicaine/2mcg/ml fentanyl infusion regime
What are the theoretical advantages of this and what other techniques can be used to provide epidural analgesia. 20 minutes after the initial bolus the lady complains of slight dizziness
Your treatment is successful and you go away for coffee. 1 hour later you are asked to
go back in as “it’s not working on one side”.
How do you assess this- what manoeuvres can you perform to improve the block? Your actions again are successful and you are happy with the quality of block until some
3 hours later when the lady is beginning to complain of “pressure down below”
You manage to improve matters, but a short time afterwards, the obstetricians tell you
that they are not happy with the CTG trace and have decided to deliver by caesarean
section.
How do you provide the anaesthesia for this? You have decided to perform this under epidural, but midway through, the patient
complains of visceral discomfort
The baby is born and the lady is immensely grateful and you go away with a satisfied
feeling of a job well done.
It can be difficult gleaning information from a distressed labouring woman, and there can be pressures to “just get on with it”, but these should be resisted. A few minutes are usually all that is required to perform a history similar to any anaesthetic assessment (including airway assessment) using all sources of information: patient, notes, and the attending midwife. Additionally you would be interested in a history of back problems, and if an epidural had been used (successfully or otherwise during her previous pregnancy.
As well as describing what is going to happen, you are also obliged to give some risk assessment. I would always inform about risk of spinal headache and hypotension and say that there may be a risk of slowing labour and increased risk of instrumental delivery- although this is not certain. It is more common nowadays to mention the rare risks of nerve damage, approx. 1 in 5000 for minor/ temporary and 1 in 50 000 for major/permanent. Consent during labour is the method used in this hospital although it is obviously not ideal, however trying to consent people beforehand is equally invalid. The best compromise is to try and ensure good antenatal information with a concise and relevant explanation at the time of insertion.
Whatever technique is used IV access is required first. Otherwise if it’s safe and aseptic it’s acceptable. Justification is required for things like LOR to air.
Alternative techniques would include top ups with 0.1% bupivicaine, with fentanyl, infusions of various solutions and patient controlled techniques with discussion of potential advantages and disadvantages of each e.g. less motor block Dizziness is obviously a potential sign of hypotension, management being moving to a lateral position on a flat bed, iv fluids, oxygen, bp measurement and ephedrine as appropriate as well as ascertaining degree of block to exclude intrathecal injection.
Assessment of block is designed to establish 1. That some epidural blockade exists, and 2. To define whether there is too low a block height, unilateral block or missed segment. Treatment options include further top up with LA with patient on the effected side, withdrawing catheter, using fentanyl and resiting as appropriate.
Rectal pressure is a classic problem late in labour and is often partially relieved by fentanyl.
Emergency section in this case would most likely be performed under epidural, with lignocaine and adrenaline being recommended in our protocols for this. There should be some discussion about the differences between lignocaine and bupivicaine and of the toxic dose ranges involved.
Visceral discomfort during epidural section is not uncommon and depending on circumstances may be managed by reassurance, more LA, Fentanyl epidurally or IV, Alfentanil IV, supplemental Nitrous Oxide, and conversion to GA or any combination of the above. Importantly GA should be offered early when other supplementation is not fully effective, and all actions documented.
Scenario 2(basic) PRMH2004- tick box when completed
A 32 year old p0+1 has been booked for an elective caesarean section for breech lie at
38 weeks gestation. She has arrived from home this morning.
What preparation should this lady have received prior to admission? What are the potential problems and benefits of admitting such patients on the day of section. You go to assess the lady prior to going to theatre.
What assessment do you make? What anaesthetic advice do you give? How do you consent this lady? You are now in theatre. The lady is fit and healthy 5 foot 4 inches tall and 77 kg. You
have decided on a spinal anaesthetic
Describe your technique. What needle do you use and why? What other needles are there? How do you calculate your dose of anaesthetic? You have decided to add diamorphine to your spinal injection.
What are the potential advantages/ disadvantages of this? What alternative drugs could be added? The spinal injection is in without too much difficulty.
How do you manage the patient now? 4 minutes after injection the lady complains of a “terrible sick feeling”
The systolic BP is low (80 mmHg) despite your initial management.
At 10 minutes you are back in control
The surgery is under way. At delivery the patient complains of some visceral discomfort.
What drugs do you give at delivery? If the discomfort continues how can you improve this? Your management has been reasonably successful and the operation is now over. The
lady is pleased with the outcome.
What are the options for post-operative analgesia here? Suggested answers
1. The woman should have completed an anaesthetic assessment form at the antenatal clinic
the previous week. If any potential anaesthetic or obstetric problems had been identified, discussions should have taken place regarding feasibility of morning admission . She should have received advice about antacid prophylaxis and been given 2 X150mg doses ranitidine to take the night before and morning of surgery.
2. Benefits to the patient include a more restful night at home rather than at night in hospital.
However if there are problems which have not been identified, this may delay surgery. In addition women can forget to take antacid prophylaxis, may forget to fast and often are late, or are delayed at the admissions desk, all of which can delay surgery. Blood has to be sent for group and save or cross match on admission. 3. Usual anaesthetic, including airway, assessment should be made. Some information will
be available on the assessment form. Advice should be given regarding types of anaesthesia. Many women have heard of epidurals, and the difference with a spinal anaesthetic should be emphasised. Women who wish a general anaesthetic should have the pros and cons of spinal and general explained. Maternal refusal is a contraindication to spinal anaesthesia, but women should be making an informed choice. It is important they understand the risks to themselves and baby of GA.
4. It is essential to discuss certain complications related to spinal anaesthesia, and document
that you have done so, either on the anaesthetic form or in the case notes. At present we recommend you explain there is a 1% headache risk , a risk of hypotension and nausea, and a risk of feeling pushing/ pulling in the abdomen during section under spinal anaesthesia. While it is important to suggest that pain may be felt, this should be done tactfully e.g. ‘you will feel some pushing and pulling, but if you feel uncomfortable or sore let me know’.
5. 16-14 g IV cannula should be inserted, and Hartmann’s solution running. The benefits of
a fluid pre-load in preventing hypotension are controversial – but our patients usually
receive 1litre during spinal insertion. With the woman either sitting or in the right lateral
position the spinal is inserted. A 24g Sprotte or Whitacre needle used. Cutting edge
needles are never used – headache rates up to 20% with 26g needles.
There is a rough correlation with maternal height and height of sensory block. Usually
2.5ml 0.5% hyperbaric bupivacaine is used. This may be reduced if the mother is
unusually small, less than 5feet, or has a multiple pregnancy, or has severe poly-
hydramnios (CSE may be used in these circumstances). We may increase the dose if the
mother is > 5foot 8 inches, or has a pre-term baby and/or severe IUGR. (Again CSE may
be the best choice).
Diamorphine appears to improve the quality of spinal block and reduce the need for
adjuvants. (300 micrograms), and when compared to fentanyl provides much extended
post-op pain relief. Disadvantages include the need to draw up another drug, and the
ampoule is non-sterile and made of glass. Always use the filter needle, but flush after as
there is quite a big dead space in the needle. Some women experience itching, but this is
normally mild, and may be reversible with nalbuphine. There is potential for respiratory
depression, but we give a modest dose, other opioids are rarely given and the women are
young.
8. The woman should lie flat, and the table is tilted 20 degrees to the left. Ensure the lateral
support is in place or someone stands at the side of the mother to prevent her rolling off the table. BP should be assessed every minute. Maternal O2 therapy has been shown to reduce the severity of nausea, but is not essential if the mother dislikes it. Pulse oximetry and ECG should be used. Early use of ephedrine for modest falls in BP usually prevents severe hypotension.
9. Nausea is almost always associated with hypotension at this time. Incremental doses of
ephedrine can be used, though an infusion may be commenced if there is early/severe falls in pressure. 10. Resistant hypotension should be treated by turning the woman fully onto her side, and
ensuring surgical delivery is hastened. Further ephedrine should be given.
Block height for surgery is commonly assessed by loss of sensation to pin prick in
published studies. In practice however there remains debate over the optimum modality: light touch and temperature also being used. The ideal upper height is T4 – at nipple level. Complete loss of sensation to pinprick is often a few segments below the level at which the mother feels the pinprick sharp rather than blunt, which can be some segments below loss of cold sensation. Additionally complete motor block at the hips and some evidence of sympathetic blockade should be confirmed before starting surgery.Document upper and lower block height on chart.
Visceral discomfort can occur despite aduquate block height. The fastest way to resolve it is to give incremental doses (250mcg) of alfentanil. Other techniques include giving
epidural fentanyl (if using CSE), or other opioids, e.g.morphine, but these are slower
acting. N2O;O2 can be given , but is less effective. Conversion to GA is rarely required if
the block height has been at T4 at the start. However, if the mother is distressed and you
cannot relieve pain, a GA should be offered, and given. Rarely, if you really feel the
distress is caused by anxiety rather than pain, then midazolam increment can be given, If
the mother is sore, and midazolam is given, it is likely to worsen her distress.
13. Post-op analgesia is usually a combination of non-steroidals and opioids. PCA morphine
is recommended by NICE, but sc morphine or oral opiates are commonly used where intrathecal diamorphine has been given. Most women receive a diclofenac suppository at the end of surgery; these can be written up 8hourly post-op. Contraindications include severe asthma or aspirin/NSAID intolerance.
Scenario 3(basic)PRMH2004- tick box when completed
35-year-old primigravid comes into pre-natal for induction of labour. She has gone
to NCT classes during her pregnancy and is keen to have a low intervention labour. She
has agreed to be induced because she is now at term +10 days.
What non-pharmacological methods of pain relief are available? She has some prostin gel PV and uses her TENS machine and then asks for some
additional analgesia.
How does TENS work? What additional analgesia should she be offered? She is now suitable for ARM and syntocinon and reluctantly has an IV inserted and
asks for more analgesia. She is not keen to have an epidural.
Which opiates can be given and how can they be administered? Would you consider inhalational analgesia for this lady? Two hours after the syntocinon has started she asks for an epidural. You go through the
usual procedures and explanations.
What drugs do you give through the epidural and how do you give them? She is very happy with her epidural and progresses in labour with her partner for
support and relaxation tapes playing in the background. Unfortunately she is very slow
to progress and 12 hours after syntocinon started the decision is made that she requires
a caesarean section.
How would you top up this patient’s epidural for section? The section proceeds with no hitches and towards the end of the section she asks you
what you are going to give her for pain relief.
What do you tell her and what other methods could you use? She tells you at the end that it wasn’t what she had planned but she is very happy with
the outcome.
SCENARIO 3
1. A patient who has been to NCT classes will be armed with a great deal of information on this subject. The method we are most familiar with is the TENS machine which is useful in early labour and for induction of labour. For pain relief in labour the electrodes are taped to the back above the pain transmitting afferent nerves which enter the posterior column of the spinal cord : one pair above both sides of the spinal processes from T10 to L1 for the first stage in labour and one pair above the spinal processes S2-S4 for the second stage in labour. The best pain relief achieved is for backache. There is a contra indication to its use if the patient has a pace- maker. Other methods include hypnosis which needs several training sessions and a skilled hypnotist, acupuncture used by only a few dedicated people and never interestingly used in Chinese culture, and psychoprophylaxis and preparation or antenatal classes where an attempt is made to prepare the woman and partner for labour. “Common sense” measures such as mobilising and warm baths should not be forgotten.
2. The pain experienced after prostin is very variable. Most women would be given paracetomol or cocodamol orally and often if priming is taking place overnight they would be given some temazepam as well. They would then be offered some diamorphine, 7.5mg I.M. if they are a primigravid and 5mg if they are parous. Usually they would be examined before further analgesia would be given.
3. After ARM and syntocinon has commenced the woman could be given further diamorphine if required. Maternal side effects of opiods are respiratory depression which is very unlikely in this situation, delayed gastric emptying which is well recognised in this situation and obviously placental transfer of drug to the fetus. Other obstetric units use pethidine which midwives have been able to prescribe since the 1950s. Usually both these drugs are given I.M. but this can take up to 30 minutes to be effective. A small I.V. amount of the drug can be useful if the patient is very distressed. P.C.A.s have been used in labour where an epidural is contra indicated or not available. The drugs used recently for P.C.A.s are fentanyl and alfentanil but as with the other opiods there will be placental transfer of the drug. Entonox can be useful ,but success depends on the mother being properly instructed and the skill of the midwife encouraging the right technique. Nitrous oxide has a low solubility (1.4) and a low blood gas partition coefficient (0.47) so that there is rapid equilibration between inspired and brain concentrations. About 50% of labouring women derive some benefit from entonox.
4. 0.25% bupivacaine is commonly used to establish a block. The test dose is 3-5mls. This is followed by 10-12mls to extend the block for labour. This can then be topped up by a suitably trained midwife with 10mls 0.25% bupivacaine. Another method is to start an infusion with 0.1% bupivacaine and 2µg/ml of fentanyl to run at 6-12mls/hour. If the mother is keen to ambulate the epidural should be established with 15mls of 0.1% bupivacaine and 2µg/ml of fentanyl and that mixture should be given for the top ups. Fentanyl is useful if the mother complains of rectal pressure. 50µg in either 10mls 0.9% saline or 0.25% bupivacaine often relieves troublesome backache or rectal pressure. P.C.E.A. is another method which can be useful. The epidural is established with 0.25% bupivacaine and then the P.C.A. is filled with 0.25% bupivacaine with no background, bolus of 4mls and a lockout of 20 minutes.
Either 0.5% bupivacaine or 2% lignocaine with adrenaline 1:200000 can be used to top up an epidural for section. Diamorphine 2 to 3 mg can be given epidurally, provided the patient is not clinically “over-opiatised” as this can supplement the intra-op block and provide good post-op analgesia.
SC morphine as hospital protocol with voltarol is the method of choice at this hospital. P.C.A. morphine is used when axial opiates have not been given. Make sure that voltarol is definately contra indicated if the patient has asthma for example because it makes a substantial difference post operatively. I.M. analgesia is used in other units and again with voltarol P.R. at time of section and given regularly works reasonably well. Fentanyl in the epidural space reduces the amount of analgesia required post section for only the first 3-4 hours. It is possible to use L.A. top ups post operatively but this can confine the patient to bed when she would rather be up and about and obviously needs the same monitoring that any epidural requires.
Scenario 4(basic) PRMH2004- tick box when completed
A 23 yr old p 0+0 with no epidural has had an ARM in the labour suite, but
unfortunately sustains a cord prolapse as a result of the procedure
What immediate management are the midwifery/obstetric staff going to do, and what implication does this situation have for you as the anaesthetist? The lady is rushed to theatre. The obstetricians are requesting immediate delivery
What anaesthetic options do you have? You prepare this lady for a General anaesthetic
What assessment do you make of the patient bearing in mind time is short? How can the airway be assessed and how reliable is this assessment? What prophylactic manoeuvres do you employ and why? You begin your anaesthetic
Describe in detail your technique including drug doses and timing. In general terms, why are we more worried about a GA in this setting than a similar induction for a patient with an acute abdomen? What are the key safety features of your technique? Having initially at laryngoscopy identified the arytenoids only, you fail to intubate at
the first attempt and lose your view
The obstetricians are desperate to get on. You decide to try again, and think this
time you have succeeded
How do you proceed from here? Imagine you are unable to intubate at this point, how would you proceed? You are convinced intubation is satisfactory, and allow the obstetricians to start
What settings do you use on your anaesthetic machine and ventilator pre delivery and why? What do you do at delivery? The operation proceeds uneventfully, a healthy- though “sleepy” baby is delivered
Your own tachycardia has settled down, and you have time to reflect on events. You
have succeeded in your aims of providing rapid, safe anaesthesia.
What do you think is the single most important adverse event to avoid during a situation like this? Are you familiar with all the equipment on our airway trolleys? What other indications for GA section can you think off? Scenario 4- suggested answers
The significance of this situation is an immediate serious threat to the life of the fetus as a cord exposed to cold air will vasoconstrict. The midwifery staff have a number of manoeuvres to attempt to “buy time” which include manually preventing any further prolapsing and putting the patient in the Hands and knees position. This is one of the situations that require immediate delivery. General anaesthetic would normally be the only option.
Assessment is of necessity limited and will take the form of rapid questioning whilst you are preparing for the GA. Important considerations include previous GA history, PMH, drugs, allergies, fasting status, dentition, as well as an assessment of the airway. Although it should be used, Mallampati testing tends to provide you with little extra useful information as it lacks specificity and sensitivity.
Prophylactic measures are: 1.H2 antagonist-usually ranitidine 50mg im or diluted IV- but it is important to appreciate that this is not going to have any significant protective effect during induction within this sort of timescale, although may help at extubation. 2. Na Citrate 30ml of 0.3 M taken orally immediately before induction designed to immediately raise gastric pH. 3. Pre-oxygenation, 4. Cricoid pressure. In other centres NG tubes are used to reduce gastric volume, but we do not routinely practice this.
This is a standard Controlled rapid sequence induction with full monitoring, and the addition of left lateral tilt. It is important not to loose sight of the fact that this is almost exactly the same as a CRSI for something such as an appendicectomy that you have done many times before.
We tend to be more concerned because of the gravid uterus causing increased gastric pressure and decreased FRC, as well as reduced oesophageal sphincter tone. In addition gastric emptying may have been further reduced by opiates. However Gastric pH is probably no lower than normal.
The key safety features are 1.gastric acid prophylaxis, 2. Pre-oxygenation, 3. Cricoid pressure.
We use Thiopentone in an adequate does to ensure anaesthesia, historically limited doses were used but this is no longer acceptable. This means a dose of around 5mg per Kg. This is followed by Suxamethonium at 1mg per Kg. Cricoid pressure is applied at the time of loss of consciousness. Scenario 5(basic) PRMH 2004 – tick box when completed
A 32 year old para 1+0 has been admitted to labour ward in established labour
having had vaginal bleeding at home. Your first involvement is 1 hour later when
she requires an urgent Caesarean section because the CTG trace is not good.
How would you assess this lady? What information do you require to decide on the appropriate anaesthetic for her C/S? On the basis of your assessment you decide to insert a spinal anaesthetic for C/S.
Anaesthesia and surgery proceed uneventfully and a 10lb baby is delivered. The
lady returns to recovery, where 45 minutes later you are asked to review her. Her
BP is 80/40, heart rate 125/minute and she is not looking well!
What is your immediate course of action? What are the most likely diagnoses? A diagnosis of atonic uterus is made on clinical grounds.
What lines of conservative management may be used to treat this? What potential complications do these treatments have? None of the above manoeuvres are successful and the decision is made to take the
patient to theatre.
How are you going to manage and anaesthetise this lady? What surgical procedures may be performed? Unfortunately a hysterectomy is required to control this patient’s bleeding.
Estimated total blood loss is 4,500ml.
What further problems might you anticipate with this lady? Outline your plans for intra- operative management. What decisions are you going to have to make at the end of the operation, and what would your post-op management be? Scenario 5 – Suggested answers
1. In addition to your usual pre-op assessment you need to ascertain the significance of this lady’s earlier vaginal bleeding. How much blood did she lose? (this is often difficult to elucidate clearly), has it happened before? (it may have been investigated – check for US reports), has it continued since admission? Bleeding around the onset of labour may be “show”, which is due the dislodging of cervical mucus and will not pose an ongoing problem. There are many causes of significant ante-partum haemorrhage but the two commonest are placental abruption (which classically causes abdominal pain) and placenta praevia (which classically presents with painless vaginal bleeding). The latter can be confirmed by US scan. It is important to assess the patient clinically as visible bleeding may not reflect total loss and there may be considerable concealed loss, especially with a placental abruption (beware the patient with a tachycardia!). Coagulopathy is a potential problem with a major abruption and torrential bleeding may occur at Caesarean section with a placenta praevia. A patient who has significant active bleeding will require general anaesthesia for C/S. Patients with a diagnosis of placenta praevia or minor abruption who are stable and not bleeding may be anaesthetised with a regional technique, but this should be discussed with a senior anaesthetist. Fortunately this lady’s bleeding had stopped and was presumed to be due to show. She was haemodynamically stable thus the decision to proceed with spinal anaesthesia.
2. The patient’s vital signs suggest that she is bleeding and your immediate action should be to speed up the IVI, give oxygen by facemask and insert a second large bore IV cannula. A sample of blood should be sent away for FBC & coagulation screen and at least 6 units of cross-matched blood should be requested. At PRMH an “acute obstetric haemorrhage pack” can be ordered at any time without the need for blood results. As she was delivered by C/S bleeding may be related to surgery or to an atonic uterus. In the case of the latter examination will reveal either bleeding per vaginum or a high fundus (due to cervical clot) with a poorly contracted uterus. NB. After vaginal delivery cervical and vaginal lacerations may cause bleeding. Bleeding may also be due to a defect of coagulation rather than a structural lesion.
3. The first manoeuvre to be performed is usually uterine massage and /or bimanual compression. Syntocinon 5 iu by IV bolus may be used. Haemodynamic effects of this include reduced total peripheral resistance and mean arterial pressure, and increased heart rate and cardiac output. These rarely require intervention, but patients frequently become flushed and complain of a pounding headache after administration of syntocinon. Onset of action is about 3 minutes, but the duration of action is only about 15 – 20 minutes, so an IV infusion (20 iu / 500ml Hartmann’s solution titrated to effect) may be required.
Ergometrine is usually the next drug to be used. It is an ergot derivative and may be given IM or IV in doses of up to 500mcg. It is a potent arterial and venous vasoconstrictor causing increased peripheral resistance, increased arterial blood pressure and reduced venous capacitance. Its use should be avoided in those patients with hypertension (pregnancy related or essential) or heart disease and care should be taken as marked increases in blood pressure may occur if it is given with ephedrine or methoxamine.
Prostaglandin F2alpha may be given IM in a dose of 250mcg. It has also been used by direct intramyometrial injection but may be rapidly absorbed by this route.
It causes systemic vasodilatation, pulmonary arteriolar constriction and increased heart rate; cardiac output and arterial blood pressure may fall dramatically. It may also cause bronchospasm and should be used with care in asthmatics.
3. This lady is actively bleeding and will require a general anaesthetic for exploratory surgery. Vigorous fluid resuscitation should be given – the level 1 blood warmer can literally be a lifesaver in these and similar circumstances. It may be necessary to give group specific, uncross-matched blood or O Rh. negative blood before fully cross-matched blood is available. General anaesthesia should follow the standard guidelines for C/S; sodium citrate should be given pre-induction as the patient is still at risk of aspiration. If bleeding is torrential resuscitation and anaesthesia may have to go hand in hand, and a smaller dose of IV induction agent should be used. Don’t forget to call for senior help! Possible surgical procedures include:(a) Exploration of the uterus for retained placenta and uterine packing.
(b) Ligation of the internal iliac arteries.
(c) Gravid hysterectomy.
5. A central venous line will both aid fluid replacement and give further venous access, and should be sited when the patient is asleep. Consideration should be given to using an arterial line. A urinary catheter will almost certainly have already been inserted preoperatively. This patient is at risk of the problems of massive blood loss: (a) Hypothermia. Use a blood warmer, foil hat, and a warm air blanket if available (if not, wrap up as much of the patient as you can) and monitor their temperature. If not using the circle system, use an HME filter.
(b) Coagulopathy. Send for blood products as clinically indicated or on the basis of FBC and coag. screen results. The Acute obstetric haemorrhage pack contains: 8 units of red cells, 4 units of FFP, and 4 units of platelets. These will be type specific if blood bank have a group and save sample, and O rh. negative if not.
Post-op you have to decide whether the patient can be wakened up and managed in HDU or requires ITU transfer. This will be a clinical judgement taking into account the whole picture. Often discussing the case early with the ITU consultant can be helpful.

Source: http://www.wosoa.org.uk/Documents/basicscenarios.pdf