discuss a patient presenting with impending carotid blow out with emphasize on management implications

1. Mawaddah Azman

2. Summary of history
 74/Chinese gentleman
 Radical Neck Dissection 8th
June 2011
 Now presents with persistent
bloody discharge from
operative wound
 He underwent Total
thyroidectomy and
functional neck dissection in
Feb 02 for Papillary Thyroid
Carcinoma
 Subsequently presented with
recurrent neck swelling in
2009, Selective Neck
Dissection performed Oct 09

3. Examination
 Wound
dehiscence
over
vertical
limb of
incision
measuring
2x1.5cm
with slow
ooze from
anterior
aspect of
the wound
 No
exposed
carotid

4. Preoperative radiological findings
 Matted, necrotic nodes at right side, encasing the
carotid artery and medially invading mucosa of the
oropharynx
 Laterally the SCM is displaced and infiltrated
 Posteriorly prevertebral muscles are involved

5. Patient progress

6. Introduction
 An emergency, pose
risk of
 Exsanguinating
haemorrhage and
potential bleeding
diathesis Threatened Impending
Acute CBS
 Compression to CBS CBS
airway
 Neurological
complications
 ClinicalCM, Citardi MJ, Ross DA, Sasaki CT. Endovascular therapy of the carotid blowout syndrome in
Chaloupka JC, Putman spectrum
head and neck surgical patients: diagnostic and managerial considerations. AJNR Am J Neuroradiol 1996;17:843–852

7. Incidence
 First recognized in 1962; with a high
mortality rate – 40%; neurologic morbidity -
60%
 occur in 3-4% of all patients who have
underwent Head and Neck Surgery 1,2.
 In advanced disease this can account for 11.6%
of head and neck cancer deaths 3,4.
1. Morrissey, D.D., Andersen, P.E. Nesbit, G.M. Barnwell, S.L. Events, E.C. Cohen, J.I. (1997) Endovascular management of
haemorrhage in patients with head and neck cancer. Archives of otolaryngology, head and neck surgery; 123:15-19
2. Koch, W.M. (1993) Complications of surgery to the neck. In complications of head and neck surgery. Edited by Eisele D. St Louis:
Mosby; 393-413
3. Shedd, D.P. Shedd, C. (1980) Problems of terminal head and neck cancer patients, Head and Neck Surgery, 2:476-482
4. Smith, A. M. (1992) Emergencies in Palliative Care, Annals Academy of Medicine, vol 23, no2, 186-190

8. Type 1: Threatened CBS
 Visibly exposed carotid artery segment that
will inevitably rupture if not covered with
a viable tissue or
 Evidence on diagnostic angiograms of
neoplastic invasion of the carotid artery or
nonhemorrhagic pseudoaneurysm
 Grading system:
 Grade 0: No evidence of vascular disruption as
seen in imaging
 Grade 1: There is focal weakening /
irregularity of the vascular wall
1. Citardi MJ, Chaloupka JC, Son YH, Sasaki CT. Management of carotid artery rupture by monitored endovascular
therapeutic occlusion (1988–1994). Laryngoscope 1995;1086-1092
 Grade 2: There is pseudoaneurysm
2. Chaloupka JC, Roth TC, Putman CM, et al. Recurrent carotid blowout syndrome: diagnostic and therapeutic
challenges in a newly recognized subgroup of patients. AJNR Am J Neuroradiol 1999;20:1069–1077
 Grade 3: There is evidence of extravasation
From The Interventional Neuroradiology Service Yale University School of Medicine 1995

9. Type 2: Impending CBS
 Presents as sentinel bleeding from the neck
which may precede ultimate blow out.
 Typically resolves spontaneously or with
surgical packing
 The period is highly variable and can range
from moments to months.
1. Citardi MJ, Chaloupka JC, Son YH, Sasaki CT. Management of carotid artery rupture by monitored endovascular
therapeutic occlusion (1988–1994). Laryngoscope 1995;1086-1092
2. Chaloupka JC, Roth TC, Putman CM, et al. Recurrent carotid blowout syndrome: diagnostic and therapeutic
challenges in a newly recognized subgroup of patients. AJNR Am J Neuroradiol 1999;20:1069–1077
From The Interventional Neuroradiology Service Yale University School of Medicine 1995

10. Type 3: Acute CBS
 Acute, profuse hemorrhage that is not self-
limiting and is not well-controlled with
surgical packing, invariably owing to
complete rupture of the affected artery.
 Torrential bleeding due to rupture of
carotid artery. This type carries the
maximum mortality since the death is
nearly instantaneous.
1. Citardi MJ, Chaloupka JC, Son YH, Sasaki CT. Management of carotid artery rupture by monitored endovascular
therapeutic occlusion (1988–1994). Laryngoscope 1995;1086-1092
2. Chaloupka JC, Roth TC, Putman CM, et al. Recurrent carotid blowout syndrome: diagnostic and therapeutic
challenges in a newly recognized subgroup of patients. AJNR Am J Neuroradiol 1999;20:1069–1077
From The Interventional Neuroradiology Service Yale University School of Medicine 1995

11. Risk factors
 Surgery to sites local to the carotid artery
 Radical Neck Dissection
 Generally 4%
 Mainly due to 3
 Removal of soft tissues protecting the carotid
 Iatrogenic or machanical injury to adventitia of the
carotids
 Decreased healing d2 removal of lymphatics and
increased venous stasis
 Risk increases
 Salvage surgery
 Flap necrosis
 Wound infection 2
1. Cohen, J. Rad, Previous irradiation 1
 I. (2004) Contemporary management of carotid blowout, Current opinion in otolaryngology & Head and Neck Surgery, 12: 110-115
2. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck oncology, Clinical
 Recurrent tumour involving the carotid artery
Otolaryngology, 5, 403-417
3. Rodriguez, F. Carmeci, C. Dalman, R.L. Lee, A. (2001) Spontaneous Late Carotid-Cutaneous Fistula following radical neck dissection- a case
report. Vascular surgery, vol 35, (5)

12. Risk factors
 Radiotherapy
 Most common factor leading to CBS 2,3,4,5
 Almost 100% of CBS occurs within an irradiated field
 Moreso if delivered within 2 months of surgery 2
 Associated with a 7.6fold increase in the risk of CBS in
patients with head and neck cancer 1.
 Aetiology
 Reduced flow in the vaso vasorum
 blood flow to the carotid wall is reduced by 50 % after a
course of 30 Gy radiotherapy course6.
 Adventitial fibrosis
 Premature atherosclerosis
 Weakening of the arterial wall, sub endothelial vacuolization and
1. Cohen, J. Rad, I. (2004) Contemporary management of carotid blowout, Current opinion in otolaryngology & Head and Neck Surgery, 12:fibres .
oedema, and fragmentation of the tunica media elastic 110-115 7
2. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck oncology, Clinical Otolaryngology, 5, 403-
417
3. Rodriguez, F. Carmeci, C. Dalman, R.L. Lee, A. (2001) Spontaneous Late Carotid-Cutaneous Fistula following radical neck dissection- a case report. Vascular surgery,
vol 35, (5)
4. Shumrick, D.A. (1973) ‘Carotid artery rupture,’ Laryngoscope, 83(7): 1051-61
5. Swain, R. E. et al (1974) An experimental Analysis of causative factors and protective methods in Carotid Artery Rupture. Arch Otolaryngology vol 99, April, 235-241
6. Smith, A. M. (1992) Emergencies in Palliative Care, Annals Academy of Medicine, vol 23, no2, 186-190
7. Huvos, A.G. Leaming, R.H. Moore, O.S. (1973) Clinicopathologic study of resected carotid artery: analysis of 64 cases. American journal of surgery, 126:570-574 Lesarge,
C. (1986)

13. Risk factors
 Postoperative impaired healing
 due to previous radiotherapy, infection and
excision of the lymphatic chains
 The carotid artery can be exposed, flap
necrosis can occur, which allows the invasion
of bacteria and further desiccation of the
adventitia 1-5.
 Improper incision: vertical limb or three
1. Cohen, J. Rad, I. (2004) Contemporary management of carotid blowout, Current opinion in otolaryngology & Head and Neck
point junction6
Surgery, 12: 110-115
2. Lesarge, C. (1986) ‘Carotid artery rupture’. Prediction, prevention and preparation. Cancer Nursing, 9 (1) 1-7
3. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck
oncology, Clinical Otolaryngology, 5, 403-417
4. Shumrick, D.A. (1973) ‘Carotid artery rupture,’ Laryngoscope, 83(7): 1051-61
5. Swain, R. E. et al (1974) An experimental Analysis of causative factors and protective methods in Carotid Artery Rupture. Arch
Otolaryngology vol 99, April, 235-241
6. Maran, A.G.D. Amin M.A. Wilson, J.A. (1989) Radical neck dissection: a 19 year experience. The Journal of Laryngology and
Otology, August, vol.103 pp 760-764

14. Risk factors
 Pharyngocutaneous fistula
 important causative factor in CBS.
 adventitia being bathed in saliva, which is
bacteria laden and damaging to the outer
lining of the arterial wall 1,3
 Fungating tumour invading the carotid
artery
 Direct infiltration destructing the arterial
wall
1. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck
oncology, Tumour necrosis increasing vulnerability of
 Clinical Otolaryngology, 5, 403-417
2. Shumrick, D.A. (1973) ‘Carotid artery rupture,’ Laryngoscope, 83(7): 1051-61
3. Swain, R. the arterial Analysis of causative factors and protective methods in Carotid Artery Rupture. Arch
E. et al (1974) An experimental wall
Otolaryngology vol 99, April, 235-241

15. Risk factors
 General systemic
 Over 50 years of age
 10-15% loss of body weight
 Diabetes mellitus and immune deficiencies
 Generalised atherosclerosis
 Malnourishment
1. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck
oncology, Clinical Otolaryngology, 5, 403-417
2. Lesarge, C. (1986) ‘Carotid artery rupture’. Prediction, prevention and preparation. Cancer Nursing, 9 (1) 1-7
3. Schiech, L. (2000) Carotid artery rupture. Clinical Journal of Oncology Nursing, vol 4, pp93-94
4. Shumrick, D.A. (1973) ‘Carotid artery rupture,’ Laryngoscope, 83(7): 1051-61
5. Swain, R. E. et al (1974) An experimental Analysis of causative factors and protective methods in Carotid Artery Rupture. Arch
Otolaryngology vol 99, April, 235-241

16. Clinical feature
 Attempt to predict patients most likely to
be at risk as sometimes there may be no
warning at all
 ‘Sentinel bleeds’ or ‘herald bleeds’
 minor bleeding from wound, flap site,
tracheostomy or mouth 2,3
 process of erosion is gradual 4
 this is caused by a small rupture of the intima
oncology, at the site 5, 403-417
Clinical Otolaryngology, of the defect of the tunica which
1. Nieto, C.S. Solano, J.M.E, Martinez, C.B. Martin, E.F. Colunga, J.C.M. Garcia, A.A. (1980) The carotid artery in head and neck
seals temporarily. 1
2. Lovel, T. (2000) Palliative care and head and neck cancer. Editorial, British Journal of Oral and Maxillofaxillofacial Surgery, 38,
253-254 Schiech, L. (2000)
3. Forbes, K. (1997) Palliative care in head and neck cancer. Clinical Otolaryngology 22:117-22
4. Macmillan, K. Stuthers, C. (1987) Algorithm for the Emergency Nursing Management of spontaneous Carotid Artery Rupture.
Canadian Critical Care Nursing Journal- March/April, 20-21

17. Clinical feature
 ‘Pulsations’ from artery or tracheostomy or
flapsite 1,2.
 ‘Ballooning’ of an artery 2,4,5.
 Haemorrhage
 externally from the neck
 internally from within the oropharynx,
 directly into the airway or tracheostomy
 Death due to:
 Hypovolaemic shock is often the cause of death.
 Asphyxiation of blood may also be a contributory
factor.
14-18  Cerebral hypoxia
1. Kane, K. K. (1983) ‘Carotid artery rupture on Advanced Head and Neck Cancer Patients’, Oncology Nursing Forum Vol 10, No.1,
2. Casey, D. (1988) ‘Carotid “Blow-out”’. Nursing Standard 2 (47): 30
3. Parsons, R. (1995) Practice Guidelines, carotid Artery rupture, Fall, vol 13, no.4, 30-31
4. Luo, C.B. Chang, F.C. Mu-Huo Teng, M. Chi-Chang Chen, C. Feng Lirng, J. Cheng, Y. (2003) Endovascular treatment of the
carotid artery rupture with massive haemorrhage, Journal of Chinese medical Association, 66, 140-147
5. Schiech, L. (2000) Carotid artery rupture. Clinical Journal of Oncology Nursing, vol 4, pp93-94

18. Patophysiology
 Adventitial layer protects the artery,
nourished by vasovasorum.
 Interrupted blood supply due to various
reasons causes destruction of arterial wall
occuring over 6-10 days 1,2
 Damage and loss of adventitia forming
eschar and slough
 Exposure of tunica media
 Sloughing of tunica media
1.  Exposureartery rupture’. Prediction,intimapreparation. Cancer Nursing, 9 (1) 1
Lesarge, C. (1986) ‘Carotid of tunica prevention and with subsequent
2. Kane, K. K. (1983) ‘Carotid artery rupture on Advanced Head and Neck Cancer Patients’, Oncology Nursing Forum Vol 10,
thinning
No.1, 14-18

19.  First case in late 18th century
 Dr John Abernathy
 Traumatic laceration of the ICA after being gored in the neck by bull’s horn
 Treated with ligation of the vessel, well tolerated by the patient

20. Management
 What has changed?
 Historically CBS was associated with 60%
neurologic morbidity and 40% mortality
 Open surgical ligation
 Outcomes substantially improved with the
advent of various endovascular surgical
techniques
 Permanent balloon occlusion (15-20% neurologic
morbidity)
in a newly  Endovascular Reconstruction of Carotid Artery
1. Chaloupka JC, Roth TC, Putman CM, et al. Recurrent carotid blowout syndrome: diagnostic and therapeutic challenges
recognized subgroup of patients. AJNR Am J Neuroradiol 1999;20:1069–1077
2. Chaloupka JC, Putmanneurologic morbidity)
(8% CM, Citardi MJ, Ross DA, Sasaki CT. Endovascular therapy of the carotid blowout syndrome in
head and neck surgical patients: diagnostic and managerial considerations. AJNR Am J Neuroradiol 1996;17:843–852
3.
 Debate over indication and selection of patients
Citardi MJ, Chaloupka JC, Son YH, Ariyan S, Sasaki CT. Management of carotid artery rupture by monitored
endovascular therapeutic occlusion (1988 –1994). Laryngoscope 1995;105:1086–1092

21. Yale
1995:
simple clinical
classification
scheme with
interdisciplinary
treatment
algorithm

22. Imaging modalities
 CT/MR
 Gold standard DSA
 Selective catheterization of each common
carotid, external carotid and or internal
carotid artery
 Active extravasation
 Pseudoaneurysm
 Tumour bleeding (nodal or primary)
 Assess intracranial circulation prior to
intervention (surgery or endovascular)
 Selective carotid and vertebral injection
 Incomplete circle of Willis

23. Management
Patient
and
family
Intent
of care
Severity of
bleeding

24. Management of non terminal
bleeding
 Resuscitation
 Airway
 Breathing
 Circulation
 Large bore branullas
 Volume replacement, preferably with blood
 Measurement of volume status
 Specific measures
 Compression
 Packing
 Hemostatic material
 Endovascular techniques
 Operative ligation

25. Endovascular treatment of CBS
 Evolved since 1980’s
 Divided into
 Deconstructive techniques: permanently occluding
 Reconstructive techniques: preserving flow
 Percutaneous Balloon Occlusion
 Using a detachable balloon (latex or silicone)
 Rapid occlusion of a large vessel can be achieved,
hence more suitable for emergent conditions
 Multiple balloons can be used in the same setting
 Achieve success rate of 95% in Type 2 &3 CBS
 Embolization with coils (platinum based),
polyvinyl alcohol or cyanoacrylate.

26. Reconstructive techniques
 Using overlapping or covered stents to diminish
‚porosity‛ between the stent struts.
 Promote sluggish flow and subsequent
thrombosis around the stent
 Allows blood flow through stent and strengthen
integrity of vessel
 Confirmed by second look angiography
 Technically more demanding and time consuming
 Indicated in patients at high risk for carotid
occlusion:
 Angiographic documentation of incomplete circle
of willis
American Contralateral carotid artery occlusion
Chaloupka, J.C. Lesley W.S.Weigele J.B. (2003) Endovascular reconstruction for the management of carotid blow-out syndrome.
journal of neuroradiology; 24: 975-981

29. Long term outcomes
 Although deployment of stent-grafts can
achieve immediate and initial hemostasis in
patients with head-and-neck cancer and CBS,
the long-term safety, stent patency, and
permanency of hemostasis appear
unfavorable.
 Complications:
 Rebleeding : periprocedure patients need to
be on antiplatelet therapy
 Thrombosis
 Persistent infection : reported brain abscess

30. Emergent endovascular techniques
 Direct carotid puncture
 Technically feasible for rapid arrest of
haemorrhage in unstable patients

31. Open technique
 Principles:
 Often done in emergency setting hence less
time for planning
 Ligate more proximally
 Ligation is preferable if there is multi level
rupture or multiple pseudoaneurysm
 Site of ligature must always be covered with
a thick viable muscle flap and is not infected
 Preferable in clinically unstable patients
 Provides rapid securing of bleeding
 Technically less demanding compared to
endovascular technique

32. Ligation of Common Carotid Artery
 Carries significant neurologic morbidity and
mortality due to variable intracranial cross
circulation
 Ideally preceded with balloon occlusion test
or angiography of collateral circulation
 Above the omohyoid
 Transverse incision middle portion of SCM
 Fascia at anterior border of SCM longitudinally
incised
 SCM retracted posteriorly
 Omohyoid tendon retracted downwards
 Carotid sheath opened
 IJV retracted laterally
 Mobilize the CCA, free from the vagus and ligate
CCA

33.  Below the omohyoid
 Transverse incision at lower portion of SCM
 Anterior jugular vein ligated
 Fascia at anterior border of SCM
longitudinally incised, omohyoid transected
 Inferiorly, carotid sheath is covered by
omoclavicular fascia
 Omoclavicular fascia exposed
 Carotid sheath opened
 IJV retracted laterally
 Mobilize the CCA, free from the vagus and

36.  The branches of the
external carotid
anastomose across
the median line.
 Superior
thyroid
 Facial
 The internal
carotids
communicate by
means of the circle
of Willis. From the
subclavian the
vertebral artery
communicates by
means of the
basilar with the
circle of Willis.
 The thyroid axis by
its inferior thyroid
branch
communicates with
the thyroid
arteries of the
opposite side.
 Finally the
superior
intercostal, which,
like the vertebral

37.  Options:
 Ligation
 End-to-end anastomosis if the rupture is small
and one level
 Interpositional grafts for reconstruction:
 Autologous graft: Saphenous vein
 Synthetic grafts:
 PTFE (Polytetrafluoroethylene)
 Dacron
 Theoretical as usually ligation is life saving
in emergency situations and rarely
anastomosis or graft reconstruction is
attempted

38. Muscular flaps
 Levator Scapulae
flap; is an option
during radical
neck dissection
 Inferior border
of muscle
divided, taking
care not to
damage the
brachial plexus
 Posterior
border of the
muscle flipped

39. Preparation for the event
 The Consultant in charge of the patient,
accompanied will break the news of the likely
occurrence of a CBS and its implications. The
information should ensure that
patients/relatives have a clear plan of care and
are aware that NO resuscitation will take
place; this must then be documented.
 In cases where herald bleeding occurs, patients
and their families will undoubtedly have been
extremely frightened and distressed by this
experience. This may have been an event which
had been unpredicted and which they were not
prepared for, in which case it may be possible
to explain how the experience may be helped in
the future with better preparation. They may be
comforted by the knowledge that sedation will

40.  Open and honest approach 1,2,4.
 Contemplating the truth, knowing what to
expect, what to do, and how distress can be
relieved can be helpful to the patient and
family 4. It may also help the patient and
family to know that, in the event of a
massive carotid rupture there should be
little pain and that death is usually very
quick 3,5.
1. Feber, T. (2000) Head and Neck Oncology Nursing. Whurr Publishers Ltd, London Chapter 2.8, 245 – 252
2. Forbes, K. (1997) Palliative care in head and neck cancer. Clinical Otolaryngology 22:117-22
When?
3.Cohen, J. Rad, I. (2004) Contemporary management of carotid blowout, Current opinion in otolaryngology & Head and Neck
Surgery, 12: 110-115
4. Kane, K. K. (1983) ‘Carotid artery rupture on Advanced Head and Neck Cancer Patients’, Oncology Nursing Forum Vol 10,
No.1, 14-18
5. Smith, A. M. (1992) Emergencies in Palliative Care, Annals Academy of Medicine, vol 23, no2, 186-190

41. The Event
 Equipments to be made available:
 Call bell
 Suction
 Syringes (10ml) for cuff inflation on a
tracheostomy tube (if appropriate)
 Bowl
 Gloves, Plastic apron, eye protector/face shield
 Dark coloured towels
 Bedside locker with attached individual drug
cabinet
 Midazolam ampoules, syringes, needles and
alcohol wipes
 Patent IV access
 Patients should be nursed in a side ward to
avoid shock and distress to other patients and

42. The Event
 Stay with the patient, hold their hand and call
for assistance calmly 1.
 Be aware of family presence and needs. Decide
beforehand with the family if they wish to stay
with the patient. Draw curtains and maintain the
privacy of the patient as much as possible 1.
 Apply towels around the bleeding site to
absorb the blood loss. If a cuffed
tracheostomy tube is insitu, inflate the cuff 2.
 Apply gentle suctioning to mouth and
tracheostomy site as necessary 2.
 Administer Midazolam intravenously 2.
 In the event of a massive, terminal bleed the
patient may be unconscious within minutes and
1. Kane, K. K. (1983) ‘Carotid artery rupture on Advanced Head and Neck Cancer Patients’, Oncology Nursing Forum Vol 10,
2. Smith, A. M. (1992) Emergencies in Palliative Care, Annals Academybefore 23, no2, 186-190
may die very quickly, even of Medicine, vol the sedation
No.1, 14-18

43. Use of Benzodiazepines
 Administration: Rapid bolus intravenous
injection
 For anxiolysis and sedation where a
catastrophic bleed occurs, give 5mg as a fast
bolus. (If no IV access is available give 5 – 10
mg as a Subcutaneous or Intramuscular
injection. Further doses may be given until
the patient is fully sedated.
 Morphine is not indicated unless:
 Patient complains of pain and or
breathlessness

44. Caring for the patient at home
 Many patients may wish to go home and may
not wish to stay in hospital, ‘waiting to
bleed’. The approach of death can evoke
feelings of loss in a dying patient.
 Loss of control may be the most
overwhelming and distressing feeling, which
is often further intensified by
hospitalization.
 Being at home may give the patient and
family privacy, control over their
surroundings, and may help the patient to
retain their own identity.
Bourne, V. Frogge, M.H. (1999) Grief, in Yarbro CH, Frogge MH, Goodman (eds) Cancer symptom management (ed 2).
 The team should discuss a management plan
Sudbury, MA Jones and Bartlett, 618-626

45. Than
k you
Questions?

46.  Sometimes, it may be necessary to block off a blood
vessel as the primary means of treating a problem. If
that blood vessel supplies the brain, doing so might
result in a stroke. However, at the base of the brain,
there can be connecting vessels which can take over the
blood supply. Because we are not certain, in some
patients, that these connections are sufficient, we do a
test beforehand. This testing involves temporarily
blocking off the blood flow in the vessel we are
interested in permanently blocking.
 We do this with a small, soft balloon placed in the
artery. With the balloon in place and inflated, we can
then perform a neurological examination on the patient
to make sure there is no problem. If the blood flow is
insufficient, the patient will start to develop
neurological impairment, such as weakness, loss of
sensation, speech problems, etc. When this happens, the
balloon is deflated to restore the normal blood flow.
Depending upon these results, we can then decide on the