Download failed spinal algorithms / drills - Anaesthetics

19 April 2013
No. 13
FAILED OBSTETRIC SPINAL
ANAESTHESIA
GW Jones
Commentator: L Gqiba
Moderator: A Torborg
Discipline of Anaesthetics
CONTENTS
INTRODUCTION ................................................................................................... 3
BACKGROUND TO OBSTETRIC REGIONAL ANAESTHESIA........................... 3
PRACTICAL APPROACH TO SPINAL ANAESTHESIA ...................................... 4
Positioning ........................................................................................................ 4
Equipment ......................................................................................................... 4
Testing the level of the block .......................................................................... 5
CLASSIFICATION OF URGENCY OF CS ............................................................ 6
Decision-to-Delivery Interval (DDI) .................................................................. 7
FAILURE .............................................................................................................. 7
The lumbar puncture ........................................................................................ 8
Injection of solution ......................................................................................... 8
Dose and spread of medication in CSF ........................................................ 10
Drug action on nerve roots ............................................................................ 10
Patient management ...................................................................................... 11
PROPOSED BEST PRACTICE .......................................................................... 12
FAILED SPINAL ALGORITHMS / DRILLS ......................................................... 12
CONCLUSION .................................................................................................... 16
COMMENTARY .................................................................................................. 16
REFERENCES.................................................................................................... 17
Page 2 of 19
INTRODUCTION
On 24 August 1898, August Bier and his assistant Hildebrandt injected cocaine
into each other’s subarachnoid space. The lack of sensation to a burning cigar, a
strong blow to the shin with an iron hammer, and pressure and traction on the
testes was described for Hildebrandt. However, Bier’s LACK of loss of sensation
was omitted from the report. His “FAILED SPINAL” was due to “equipment/
operator failure” resulting in leakage of cocaine solution from the connection
between the needle and syringe.(1)
Although the cause of Bier’s failure was an obvious one, what is more puzzling
are the standard uncomplicated spinal anaesthetics which then fail to produce an
adequate sensory block.
BACKGROUND TO OBSTETRIC REGIONAL ANAESTHESIA
In 1900, two years after Bier’s experiment, an obstetrician named Oskar Kreis was
the first to achieve spinal anaesthesia for labour pain relief using cocaine. It was a
number of years before this practice gained general acceptance.(2) Now, spinal
anaesthesia has become the preferred choice of anaesthetic for caesarean
section (CS) due to rapid onset, predictable and reliable block and excellent
postoperative analgesia, as well as the avoidance of the risks of general
anaesthesia (GA) such as airway difficulties and drug toxicity to the babies.
Furthermore, most women now want to be awake for their CS to strengthen the
parental bonding with themselves and their partners.(3, 4)
Given the above advantages, the use of regional anaesthesia, and more
specifically spinal anaesthesia, for CS has increased dramatically over the last 10
– 20 years. Three other regional techniques are used, namely epidural
anaesthesia, ‘continuous’ spinal and combined spinal-epidural anaesthesia (CSE).
The main advantages of a spinal over an epidural are faster onset and a more
predictable and denser block with improved patient comfort. The disadvantages of
a single shot spinal anaesthetic include profound hypotension, inability to prolong
block and a small risk of post-dural puncture headache. The CSE combines the
advantages of both spinal and epidural techniques ie. rapid onset and dense block
as well as the ability to ‘top up’ the block using the epidural catheter.(5)
The CSE technique is being used more frequently as the globally increasing trend
in CS leads to more repeat surgeries with associated increased risk of placenta
praevia, increasing surgical complexity as well as prolonged operating time
(>90min) .(6) Postpartum sterilization has also been shown to be an independent
risk factor for partial failure often requiring the use of the CSE technique. (3)
Page 3 of 19
PRACTICAL APPROACH TO SPINAL ANAESTHESIA
Positioning
There has been much debate and numerous small studies performed over the
optimal position for induction of spinal anaesthesia for CS. Inglis et al (7) found that
there was no difference in the onset of the block to T4 between the lateral and
sitting positions even though the spread of block was faster in the lateral position.
The authors also claimed that the sitting position allowed for faster and easier
insertion with the result that total time to readiness for surgery was no different
between lateral and sitting insertion positions. This has contributed to the adoption
of the sitting position as a standard practice.
Russell I (8) has contested this routine and has highlighted that anaesthetists
trained in the use of the sitting position and who use it preferentially are not skilled
in the use of the lateral position. The opposite is true of those trained and skilled in
the lateral position ie. those using the lateral position preferentially are proficient in
both positions. He further states that the routine use of the sitting position creates
a partially trained workforce, unsuitable for delivery of spinal anaesthesia and that
routine use of sitting position for spinal anaesthesia should be avoided.(8)
Equipment
The development of needles for spinal anaesthesia has been geared towards the
reduction of post dural puncture headaches (PDPH). Needle sizes are much
smaller to reduce the hole made in the dura and it is now generally accepted that
spinal anaesthetics are not performed with needles larger than a 25 gauge unless
there are compelling reasons to the contrary.
Another design development to reduce PDPH is the introduction of pencil-point
needles. Sharp-edged ‘cutting’ needles such as the Quincke cut the fibres of the
dura thus increasing the risk of PDPH. Pencil-point needles such as Whitacre or
Sprotte ‘separate’ rather than cut dural fibres, and allow them to close once the
needle is withdrawn. However, as will be shown later in the booklet, the Sprotte
design does have its own drawbacks.
Page 4 of 19
The different types of needles used for spinal anaesthesia along with the type of point at
the end of each type of needle.
http://www.nysora.com/regional_anesthesia/neuraxial_techniques/3119-spinal_anesthesia.html
Testing the level of the block
Testing the level of the block is performed using three modalities: touch, sharp
pinprick and cold. In general loss of sensation to touch is several dermatomes
lower than pinprick which in turn is several dermatomes lower than cold. This is
important in not only dosing studies but also in clinical practice as the anaesthetist
needs to be aware of the implications of an assumed adequate level of block with
subsequent discomfort or pain for the patient. There is also great variability
between and within patients to the 3 different modalities.(9)
The level required for skin incision for CS is the T10 dermatome. However a
number of visceral organs send sympathetic afferent impulses to the thoracic
spinal cord and require a block level to T4. If this is not achieved a dull, cramping
visceral-type pain is often felt leading to a ‘failed’ spinal.(4) Russell has shown that
when the block to touch is lower than T5, patients often feel pain. Surprisingly, in
these patients the corresponding block to cold or pinprick was much higher than
T4 and often at the cervical level. Accordingly Russell states that if T5/6 is the
required block level to touch then a block level to pinprick and cold of 2 and 4
dermatomes higher respectively should be obtained. (10)
Page 5 of 19
The table below shows some of the methods that can be used to test the various modalities.
Sensory modality and method of application that may be used to test the level of neuraxial block
(10)
CLASSIFICATION OF URGENCY OF CS
The traditional classification of caesarean section (CS) into either elective or
emergency is now being superseded by one which grades the degree of urgency
of the CS. This four category classification of urgency of CS was developed in
2000 to improve audit data collection Not only does this new grading system
allow for more accurate audit of baby outcomes, but it also improves
communication and minimises misunderstanding between healthcare
professionals as to the urgency of delivery. A further modification is the application
of a colour scale which emphasises the need to acknowledge that a ‘continuum of
risk’ applies to caesarean section rather than discrete categories (11, 12)
A Classification relating to the degree of urgency to the presence or absence of maternal or
foetal compromise(12)
Grade 1: includes CS for acute severe bradycardia, cord prolapse, uterine
rupture, foetal blood sampling pH less than 7.2.
Grade 2: there is ‘urgency’ to deliver the baby in order to prevent further
deterioration of either the mother or baby’s condition (e.g. antepartum
haemorrhage, ‘failure to progress’ in labour with maternal or foetal
compromise).
Page 6 of 19
Grade 3: includes CS carried out where there is no maternal or foetal compromise
but early delivery is necessary (e.g. a woman booked for planned CS
who is admitted with pre-labour SROM or ‘failure to progress’ with no
maternal or foetal compromise).
Grade 4:includes all CS carried out ‘electively’ at a planned time to suit the mother
and clinicians.(11)
Categories 1 – 3 are regarded as ‘Emergency’ and category 4 as ‘Elective’.
Decision-to-Delivery Interval (DDI)
The DDI for unplanned CS (category 1 & 2) remains controversial. The DDI was
initially introduced as an audit standard for the performance of the delivery team
as a group and not as a guide for practice, particularly the 30 minute interval. The
latest NICE review in 2011has provided further clarification: (11, 12)
1. Perform category 1 & 2 CS as soon as possible after making the decision
2. Perform category 2 CS within 75 min in most instances
3. When decisions are made about expedited delivery, the condition of the
mother and unborn baby should be taken into account, bearing in mind that
rapid delivery may be harmful in certain circumstances.
4. The following DDIs should be used to measure the overall performance of
an obstetric unit:
i. Category 1 CS: 30 min
ii. Category 2 CS: 30 min and 75 min
FAILURE
Managing a spinal anaesthetic which is inadequate for surgery can be extremely
challenging and doctors need to be aware of all possible reasons for failure. The
anaesthetic technique must be performed in such a way as to maximise the
chance of success.
Failure of regional anaesthesia is defined in a number of ways:(13)
1. Pain during surgery
2. Conversion to GA (general anaesthesia)
3. Conversion to any other form of anaesthesia
4. Inability to achieve a defined degree of nerve block adequate for CS
(epidural top up)
Failed spinal anaesthesia may be partial or complete and may require
administration of various adjuvants or conversion to general anaesthesia which
may have medicolegal implications. In fact the most commonly cited cause of
litigation in obstetric anaesthesia is discomfort during spinal anaesthesia for CS.(3)
There are essentially 5 phases of a spinal anaesthetic which when they go awry
can result in an inadequate block:(14)
1. The lumbar puncture
2. Injection of solution
3. Spread of medication in CSF (cerebrospinal fluid)
Page 7 of 19
4. Drug action on spinal nerve roots and spinal cord
5. Subsequent patient management
The lumbar puncture
Absent CSF or ‘dry tap’ is the only cause of failure that is immediately obvious.
The two main factors contributing to this are positioning, the importance of which
has already been addressed and incorrect needle insertion. Both these factors are
worsened by abnormalities of the spine (scoliosis, kyphosis, calcification of
ligaments and osteoporosis), patient anxiety and obesity.
A study by Faitot et al showed that the factors associated with difficult epidural
placement in resident anaesthesiologists were body mass index >30 kg/m2, an
abdominal circumference >105 cm, inability to palpate spinous processes and
spinal abnormality.(15)
The usual approach for needle insertion is midline but lateral or para-median are
also used, especially when midline approach is unsuccessful. It is thus advisable
for the anaesthetist to understand the relevant anatomy and have a ‘mental
picture’ of the location of the advancing needle tip. This may become less
important as technology advances and ultrasound guided insertion becomes more
commonplace.
Injection of solution
A less common but well described and increasing cause of failure despite a
seemingly easy and routine insertion are the presence of extradural cysts such as
Tarlov’s, arachnoid and dermoid cysts, and cystic neuromas. Tarlov or perineural
cysts with an estimated incidence of 4.5 to 9% are formed within the nerve-root
sheath at the dorsal root ganglion in the lumbosacral region and arise de novo or
following trauma or surgery. Although they contain CSF, communication with the
intrathecal space may be absent, allowing free flow of CSF but not allowing
injected local anaesthetic to reach the cauda equina and thus preventing
anaesthesia. This would explain the not uncommon scenario of two seemingly
successful spinal injections with no anaesthetic effect followed by success with
local anaesthetic injected through an epidural catheter. (16)
Lacassie et al(17) described two case reports of failure of continuous spinal
anaesthesia to provide adequate surgical block in patients with Marfan’s
syndrome. These were thought most likely to be due to dural ectasia, both of
which were confirmed on CT scan.A further cause of apparent successful
intrathecal injection without anaesthetic effect is the excessive subcutaneous
injection of local anaesthetic which may distort the anatomy and mimic the feel of
a normal needle insertion with free flow of clear fluid.
More obvious causes of misplaced injectate are failure to secure the syringe into
the hub of the needle and allowing a small amount, but large percentage, of local
anaesthetic to be lost.
Page 8 of 19
The chances of this can be minimised by firmly securing the syringe to the hub.
This however can cause movement of the needle giving rise to another cause of
injectate loss. A more subtle cause of injectate loss can occur with the pencil-point
needle as depicted below. If the needle is positioned correctly, all the local
anaesthetic will be deposited in the subarachnoid space but if the opening lies
across the dura, part of the injectate will be lost in the epidural space.
Possible positions of the tip of a pencil-point needle (14)
The dura / arachnoid may also act as a ‘flap’ valve, allowing CSF to be aspirated
but on injection causing it to be displaced.
To show how the dura or arachnoid mater may act as a ‘flap’ valve across the opening of a
pencil point needle (14)
Page 9 of 19
Dose and spread of medication in CSF
The most important factor in determining the speed of onset, quality and duration
of the block is the dose of the local anaesthetic. However, the most important
factors in determining the spread and hence level of sensory block are the density
/ baricity of the solution, the CSF volume and the position of the patient.(14, 18).
Interestingly, Ruppen et al showed a six fold difference in CSF bupivacaine
concentrations in patients demonstrating the same level of block: 95.4 to 773.0
Ug/ml (median 242.4 Ug/ml) and from 25.9 to 781.0 Ug/ml (median 187.6
Ug/ml).(18)
Both Riley (4) and Ginosar et al (19) have found no advantage in administering
lower doses of bupivacaine and suggest a dose of 12mg bupivacaine. In a doubleblind, randomized, dose-ranging study of intrathecal bupivacaine together with
fentanyl 10Ug and morphine 200Ug Ginosar et al concluded that the ED50
(Effective Dose) for success(induction) and success(operation) were 6.7 and 7.6
mg, respectively, whereas the ED95 for success(induction) and
success(operation) were 11.0 and 11.2 mg. The study was unfortunately not
powered to detect a difference in side effects using lower doses. They also stated
that when lower doses of bupivacaine are used, a CSE technique should be
employed.
In our practice we use 9 mg of bupivacaine with 20Ug of fentanyl which is midway
between the ED50 and ED95. A study by Carvalho et al (20) found that parturients
who were breastfeeding were less likely to request analgesics due to possible
adverse effects on their babies. This reinforced the importance of good intra and
post operative analgesia in patients undergoing regional anaesthesia. They stated
that although the lowest possible dose of bupivacaine is recommended to
minimise side effects such as maternal hypotension, nausea, shivering and
prolonged stay in the PACU (post anaesthetic care unit), this reduced dose was
also associated with intraoperative pain and failure of block in prolonged surgery.
Drug action on nerve roots
A final cause of failure assuming the drug reaches the nerves but does not
produce the desired effect could have the following possible explanations:
a. The incorrect drug may have been administered. The risk of this is reduced
by using the same local anaesthetic for skin and soft tissue infiltration as for
the spinal itself
b. Chemical incompatibility due to mixing of 2 or more drugs in the syringe
causing either precipitation or lowering of the pH resulting in decreased unionised fraction and less movement into nerve root
c. Inactive local anaesthetics. Although the newer amide-linked local
anaesthetics are more stable than the older ester-linked ones and can be
heat sterilised in solution there have been a number of case reports and
case series challenging the efficacy of local anaesthetic solution – and not
only the generic but also the originator.(16, 21, 22)
Page 10 of 19
The United States Food and Drug Administration (USFDA) has stated that
bupivacaine is ‘heat intolerant’ and exposure to extreme heat may cause
loss of potency. The package insert also states that that storage
temperature should be 15-30.8C.
d. Very rarely and only a few case reports of suspected local anaesthetic
resistance possibly due to sodium channel mutation rendering the local
anaesthetic ineffective.(1)
The table below shows a number of strategies to reduce the risk of drug errors.
One of these is a current initiative by the National Patient Safety Agency (NPSA)
in the UK which aims to change the equipment used to access the nervous
system by requiring that connectors used for neuraxial anaesthesia are unable to
connect to the Luer connector used in other small bore equipment, particularly for
intravenous use.
Suggested steps to reduce the risk of drug errors (23)
Patient management
Even though a spinal anaesthetic may be adequate in terms of lower body
somatic and autonomic nerve block, there are other components of the nervous
system that need to be managed ie. the patient’s conscious awareness of the
clinical setting and transmissions of ‘sensations’ from intra-abdominal stimuli
through unblocked parasympathetic and phrenic nerve fibres. Patients
expectations play a major role and if their anxiety and concerns are not allayed,
they are more likely not to cope and claim that the anaesthetic has not worked
leading to increased litigation.(14)
Page 11 of 19
PROPOSED BEST PRACTICE (24)
The Royal College of Anaesthetists (RCOA) suggest that, in keeping with the best
practice, the conversion rate from spinal anaesthesia to general anaesthesia
should be less than 1% for elective caesarean section and less than 3% for nonelective caesarean section.
The table below gives an indication of what numbers each obstetric unit should be
aiming for in terms of failure of regional anaesthesia. The numbers relate to all
forms of RA and not only spinal anaesthesia. The definition of regional
anaesthesia in this publication is rather stringent as it includes labour regional
anaesthesia as a failure even when not used by choice for CS. The rationale is
that it should be possible to convert an effective labour epidural into an adequate
block for surgery.
They have determined three main options: % CS carried out with RA, % pain
during RA, % conversion from RA to GA and divided each into three categories
(Cat) based on the classification of urgency of CS: Cat 4, Cat 1- 3 and Cat 1.
Proposed standard or target for best practice(24)
Some of the common reasons for failure to meet these standards include:(24)
1. Lack of a dedicated obstetric anaesthetist. Staff inexperience.
2. Misunderstanding/misclassifying urgency. Poor selection of RA type in
complex cases.
3. Inappropriate assessment/recording of block.
FAILED SPINAL ALGORITHMS / DRILLS
The anaesthetist should perform a complete pre-anaesthetic evaluation (25),
including past medical and surgical history, previous complications with
anaesthesia, any problems during the pregnancy, a thorough airway and back
anatomy assessment as well as an assessment of the foetal condition. Informed
consent should also be obtained for both regional and general anaesthesia due to
the risk of a failed or inadequate block and subsequent conversion to a general
anaesthetic.
Resuscitation drugs and equipment as well as difficult airway equipment should
be readily available. Due to the often time-pressured nature of obstetric
anaesthesia, decisions and actions need to be made rapidly.
Page 12 of 19
Doctors administering the spinal anaesthetic should have a pathway to follow
when the block has failed or is incomplete. Accordingly it is proposed that a “failed
spinal” drill is as essential to learn and practice as a failed intubation drill.
The figure below is the first draft of the University of KwaZulu-Natal (UKZN) Failed
Spinal Algorithm.
UKZN FAILED SPINAL ALGORITHM
Airway assessment
1. Laryngoscopy
2. Mask Ventilation
3. Rescue: a. Supraglottic
b. Infraglottic
Airway Equipment
1. Supraglottic
LMA Proseal™/ Supreme™
2. Infraglottic
Cricothyrotomy
Impossible Spinal
GA: All 3 Difficult = Awake
Failed Spinal: Elective
Pre-incision: Repeat block
Post-incision
Extra-peritoneal: GA
Intra-peritoneal: 70 % N2O to delivery then
sedation / GA
Failed Spinal: Emergency
Pre-incision: GA / x1 Repeat
Post-incision: same as Elective (above)
Suggested UKZN FAILED SPINAL ALGORITHM (26)
A search of the literature revealed very few “failed spinal” algorithms.
City Hospitals Sunderland NHS Trust has one of the most comprehensive and
useful algorithms for inadequate regional anaesthesia during LSCS (Lower
Section Caesarean Section) (27)
Page 13 of 19
City Hospitals Sunderland NHS Trust: Inadequate Regional Anaesthesia during LSCS
In an audit by Kinsella (13) of over 5000 CSs under regional anaesthesia, pain
during the operation was split into mild or severe, based on a cut-off for mild pain
of up to 1 mg alfentanil or 100 Ug fentanyl, and the use of only one type of
analgesia. In the same audit by Kinsella the initial spinal dose was bupivacaine
12.5mg with diamorphine 300Ug. There was an inadequate block following spinal
anaesthesia in 15 patients and the use of bupivacaine 9mg as a repeat dose did
not cause any high blocks.
There is little data in the literature regarding what dose of bupivacaine to use in a
repeat spinal. Fettes et al(14) addresses this dilemma succinctly by saying that the
specific management will depend on the nature of the failure and the time at which
it becomes apparent. One should allow 15 - 20 minutes after insertion before
determining that the spinal anaesthetic has failed and the repeat dose should be
dependent on the degree of residual block. Some anaesthetists feel that ideally a
CSE should be used allowing a minidose spinal with the possibility of a top up if
needed.
Another ‘failed spinal’ algorithm has been created as a consensus view by the
anaesthetists at the Aberdeen Maternity Hospital.(28)
Page 14 of 19
The principles are essentially the same as at UKZN and City Hospitals
Sunderland but as with these, more specifics should be included as to the doses
of drugs used for supplemental analgesia as well as appropriate dosing for repeat
spinal injection.
Aberdeen Maternity Hospital Inadequate Spinal Anaesthesia algorithm
Page 15 of 19
(28)
CONCLUSION
The latest National Committee on Confidential Enquiry into Maternal Deaths
(NCCEMD) report (Triennium 2008 – 2010) has shown that maternal deaths from
spinal anaesthesia are gradually increasing. Spinal anaesthesia in inexperienced
hands is associated with significant maternal mortality. (29) The misconception that
spinal anaesthesia can be performed safely by a doctor lacking general
anaesthesia skills is seen in advertisements for medical officers in SA. For
example, one district hospital listed ‘perform spinal anaesthesia’ as a key
competency. A more appropriate competency would be ‘capable of providing
anaesthesia’ and include all forms of anaesthesia relevant to the procedures
required to be performed at a district hospital. (25)
The first part of the title of a recent article by Farina and Rout “But it’s just a
spinal” (25) aptly summarises the attitude of many doctors, but as shown here,
there are many factors involved in achieving and managing a satisfactory block –
and that is excluding all the complications of the spinal anaesthetic. A ‘failed
spinal’ algorithm should encompass all factors relating to an inadequate regional
block and should assist the physician in managing all forms of ‘failure’ and so
reducing maternal and foetal morbidity and mortality as well as pursuant litigation.
COMMENTARY
Review of the weight of evidence in articles used for production of booklet
Level
1a
Systematic Reviews & Metaanalyses
1b
Randomized
controlled
double blind studies
2
Cohort studies
3
Case Control Studies
Case Series
Case Reports
4
Editorials & Opinions
No. References
4
4; 11;14; 29
1
19
5
1
3
0
16
3; 7; 13;15; 20
5
16; 17; 18
1; 2; 6; 8 9; 10; 11; 12; 21; 22; 23;
24; 25; 26; 27; 28
Page 16 of 19
REFERENCES
1. Drasner K. Spinal anaesthesia: a century of refinement, and failure is still an
option. British journal of anaesthesia. 2009;102(6):729-30. Epub 2009/05/20.
2.
Schneider MC, Holzgreve W. [100 years ago: Oskar Kreis, a pioneer in spinal
obstetric analgesia at the University Women's Clinic of Basel]. Der
Anaesthesist. 2001;50(7):525-8. Epub 2001/08/11. Vor 100 Jahren: Oskar
Kreis, der Pionier der ruckenmarknahen geburtshilflichen Analgesie an der
Universitatsfrauenklinik Basel.
3.
Sng BL, Lim Y, Sia ATH. An observational prospective cohort study of
incidence and characteristics of failed spinal anaesthesia for caesarean
section. International Journal of Obstetric Anesthesia. 2009;18(3):237-41.
4.
Riley ET. Regional anesthesia for cesarean section. Techniques in Regional
Anesthesia and Pain Management. 2003;7(4):204-12.
5.
Riley ET, Cohen SE, Macario A, Desai JB, Ratner EF. Spinal versus epidural
anesthesia for cesarean section: a comparison of time efficiency, costs,
charges, and complications. Anesthesia and analgesia. 1995;80(4):709-12.
Epub 1995/04/01.
6.
Sia ATH, Fun WL, Tan TU. The ongoing challenges of regional and general
anaesthesia in obstetrics. Best Practice & Research Clinical Obstetrics &
Gynaecology. 2010;24(3):303-12.
7.
Inglis A, Daniel M, McGrady E. Maternal position during induction of spinal
anaesthesia for caesarean section. A comparison of right lateral and sitting
positions. Anaesthesia. 1995;50(4):363-5. Epub 1995/04/01.
8.
Russell IF. Routine use of the sitting position for spinal anaesthesia should be
abandoned in obstetric practice. International Journal of Obstetric Anesthesia.
2008;17(4):343-7.
9.
Russell IF. Editorial: Assessing the block for caesarean section. International
Journal of Obstetric Anesthesia. 2001;10(2):83-5.
10. Russell IF. At caesarean section under regional anaesthesia, it is essential to
test sensory block with light touch before allowing surgery to start.
International Journal of Obstetric Anesthesia. 2006;15(4):294-7.
11. NICE. Caesarian Section - NICE Clinical Guideline. wwwniceorguk. 2011.
2004.
12. Brennard JE MPea. CLASSIFICATION OF URGENCY OF CAESAREAN
SECTION – A CONTINUUM OF RISK. Joint Standing Committee of the
Royal College of Anaesthetists and the Royal College of Obstetricians and
Gynaecologists. April 2010;Good Practice No. 11.
13. Kinsella SM. A prospective audit of regional anaesthesia failure in 5080
Caesarean sections. Anaesthesia. 2008;63(8):822-32. Epub 2008/06/13.
Page 17 of 19
14. Fettes PD, Jansson JR, Wildsmith JA. Failed spinal anaesthesia:
mechanisms, management, and prevention. British journal of anaesthesia.
2009;102(6):739-48. Epub 2009/05/08.
15. Faitot V, Ourchane R, Dahmani S, Magheru M, Nebout S, Gomas F, et al. An
observational study of factors leading to difficulty in resident
anaesthesiologists identifying the epidural space in obstetric patients.
International Journal of Obstetric Anesthesia. 2011;20(2):124-7.
16. Hoppe J, Popham P. Complete failure of spinal anaesthesia in obstetrics.
International Journal of Obstetric Anesthesia. 2007;16(3):250-5.
17. CEMD. Saving Mothers’ Lives: Reviewing maternal deaths to make
motherhood safer: 2006–2008. BJOG: An International Journal of Obstetrics
& Gynaecology. 2011;118:1-203.
18. Ruppen W, Steiner LA, Drewe J, Hauenstein L, Brugger S, Seeberger MD.
Bupivacaine concentrations in the lumbar cerebrospinal fluid of patients
during spinal anaesthesia. British journal of anaesthesia. 2009;102(6):832-8.
Epub 2009/03/31.
19. Ginosar Y, Mirikatani E, Drover DR, Cohen SE, Riley ET. ED50 and ED95 of
intrathecal hyperbaric bupivacaine coadministered with opioids for cesarean
delivery. Anesthesiology. 2004;100(3):676-82. Epub 2004/04/28.
20. Carvalho B, Cohen SE, Lipman SS, Fuller A, Mathusamy AD, Macario A.
Patient preferences for anesthesia outcomes associated with cesarean
delivery. Anesthesia and analgesia. 2005;101(4):1182-7, table of contents.
Epub 2005/09/30.
21. Kuczkowski KM. Summer in San Diego, or failed spinal anesthesia: Chemical
versus technical phenomenon? Annales Françaises d'Anesthésie et de
Réanimation. 2008;27(1):113.
22. Smiley RM, Redai I. More failed spinal anesthetics with hyperbaric
bupivacaine. International Journal of Obstetric Anesthesia. 2004;13(2):132-4.
23. Kinsella SM. The shock of the ‘Nuer’: the UK experience with new non-Luer
neuraxial equipment and implications for obstetric anaesthesia. International
Journal of Obstetric Anesthesia. 2013;22(1):1-5.
24. Kinsella M ea. Royal College of Anaesthetists | Raising the Standard: a
compendium of audit recipes | 3rd Edition. 2012.
25. Farina Z, Rout C. 'But it's just a spinal': combating increasing rates of
maternal death related to spinal anaesthesia. South African medical journal =
Suid-Afrikaanse tydskrif vir geneeskunde. 2013;103(2):81-2. Epub
2013/02/05.
Page 18 of 19
26. Hodgson E SR, Jones G. UKZN Failed Spinal Algorithm. 2012.
27. Eason S MM. Guidelines for inadequate regional anaesthesia during LSCS.
2010.
28. Guidelines AMHA. Testing Spinal Anaesthesia Prior to Caesarean Section.
2009(Version 1.2 38).
29. Dyer RA, Reed AR, James MF. Obstetric anaesthesia in low-resource
settings. Best Practice & Research Clinical Obstetrics & Gynaecology.
2010;24(3):401-12.
Page 19 of 19