do#we#need#neuromuscular#blockers#...

Dr. J. P. Mulier, MD PhD

Geneeskundige dagen Antwerpen

September 16 th 2010

Antwerpen, Italy

Do we need Neuromuscular blockers (NMB) in morbid obese pa8ents

undergoing laparoscopy?

1 16 sept 2010 Geneesk dagen Antwerpen

Introduction Obesity is a growing general health problem


Bariatric surgery is more effec7ve in reducing weight


Bariatric surgery reduces morbidity ORIGINAL ARTICLE

Surgery Decreases Long-term Mortality, Morbidity, andHealth Care Use in Morbidly Obese Patients

Nicolas V. Christou, MD, PhD, John S. Sampalis, PhD, Moishe Liberman, MD, Didier Look, MD,Stephane Auger, BSc, Alexander P.H. McLean, MD, and Lloyd D. MacLean MD, PhD

Objective: This study tested the hypothesis that weight-reduction(bariatric) surgery reduces long-term mortality in morbidly obesepatients.Background: Obesity is a significant cause of morbidity andmortality. The impact of surgically induced, long-term weight losson this mortality is unknown.Methods: We used an observational 2-cohort study. The treatmentcohort (n ! 1035) included patients having undergone bariatricsurgery at the McGill University Health Centre between 1986 and2002. The control group (n ! 5746) included age- and gender-matched severely obese patients who had not undergone weight-reduction surgery identified from the Quebec provincial health insur-ance database. Subjects with medical conditions (other then morbidobesity) at cohort-inception into the study were excluded. The cohortswere followed for a maximum of 5 years from inception.Results: The cohorts were well matched for age, gender, andduration of follow-up. Bariatric surgery resulted in significant re-duction in mean percent excess weight loss (67.1%, P " 0.001).Bariatric surgery patients had significant risk reductions for devel-oping cardiovascular, cancer, endocrine, infectious, psychiatric, andmental disorders compared with controls, with the exception ofhematologic (no difference) and digestive diseases (increased ratesin the bariatric cohort). The mortality rate in the bariatric surgerycohort was 0.68% compared with 6.17% in controls (relative risk0.11, 95% confidence interval 0.04–0.27), which translates to areduction in the relative risk of death by 89%.Conclusions: This study shows that weight-loss surgery signifi-cantly decreases overall mortality as well as the development of newhealth-related conditions in morbidly obese patients.

(Ann Surg 2004;240: 416–424)

In recent years, morbid obesity has emerged as a seriouspublic health threat. After smoking, it is the second leading

cause of preventable, premature death in the United States. Itis estimated that there are 400,000 deaths attributable toobesity in the United States each year.1 The World HealthOrganization has recognized an epidemic of obesity through-out most of the developed and developing world.2 Canadianadult obesity trends have grown during a 13-year period from5.6% in 1985 to 14.8% in 1998.

Obesity is associated with multiple complications andrelated comorbidities that lead to both physical and psycho-logic problems.3–6 Bariatric surgery has been shown to be aneffective method for producing weight loss in obese patientsin both the short and long term7–11 and to be more effectivethan dieting in producing sustained weight loss.12 To date,there has not been a population-based study demonstrating asignificant impact of surgically induced permanent weightloss on mortality and the prevention of comorbidity in severeobesity. The current study addresses these issues by compar-ing the outcomes in 2 cohorts of morbidly obese patients.

METHODS

Study DesignThis was an observational 2-cohort study that compared

the morbidity and mortality of a cohort of morbidly obesepatients treated with bariatric surgery at the McGill Univer-sity Health Centre (MUHC) to that of matched morbidlyobese controls who had not been treated surgically. Theinception time of the bariatric cohort was the time of admis-sion for surgery. The inception time for the control group wasthe date of surgery of their matched bariatric patients. Amaximum of 6 controls were identified for each bariatricsubject. The 2 cohorts were followed for a maximum of 5years. The MUHC Research Institute ethics board approvedthe study.

Identification of Study CohortsA total of 1118 patients underwent bariatric surgery for

the treatment of morbid obesity at the MUHC betweenJanuary 7, 1986, and June 8, 2002. The unique health insur-

From the Section of Bariatric Surgery, Division of General Surgery, Depart-ment of Surgery, McGill University, Montreal, Quebec, Canada.

Reprints: Nicolas V. Christou, MD, PhD, Room s9.30, 687 Pine Ave. W., Montreal,Quebec, Canada H3A1A1. E-mail: [email protected].

Copyright © 2004 by Lippincott Williams & WilkinsISSN: 0003-4932/04/24003-0416DOI: 10.1097/01.sla.0000137343.63376.19

Annals of Surgery • Volume 240, Number 3, September 2004416

morbidity indicators, ie, excluding those with a history of theoutcomes, and matching the controls with respect to theduration of disease and age are key elements of the study’sdesign. These elements make the current study an excellentsimulation of a prospective cohort study and a valid repre-sentation of a “real-life” situation.

The results of the current study show that for up to 16years after bariatric surgery, patients experience significantand sustained weight loss. This result is expected and com-patible with those reported in other studies. The resultsshowing reduced mortality, reduction in the development of

new comorbid conditions, and reduced health care use aftersurgery in combination with the demonstrated effectivenessin weight loss are unique findings of the current study.

The effects of morbid obesity on the risk for hyperten-sion, coronary artery disease, and vascular disorders23,24;diabetes25,26; cancer27; and respiratory conditions28,29 havebeen well documented. In the current study, patients havingundergone bariatric surgery had significantly reduced risk ofdeveloping cancer, cardiovascular disease, endocrinologicaldisorders, infectious diseases, musculoskeletal disorders, andrespiratory conditions.

The increased risk for gastrointestinal disorders in thesurgery cohort was expected, and one that we feel serves asan internal consistency check of the analysis. After surgery,some patients experience stenosis of the vertical bandedoutlet, stenosis of the gastrojejunostomy, stomal ulcers, gas-tro-gastric fistula, small bowel obstructions, incisional her-nias, dumping syndrome, and diarrhea.30 Thus, one expects tosee increased physician visits and hospitalizations for treat-ment of these conditions.

Morbid obesity increases the risk for mortality.31,32 Thecurrent study demonstrates that in patients being treated withbariatric surgery, the risk of 5-year mortality is reduced by89%. This is a significant observation because it not onlysuggests the role of morbidity as a risk factor for earlymortality but also provides evidence that surgical treatment ofobesity produces a significant reduction in mortality. We feelthat the improved weight loss due to the efficacy of the RYgastric bypass and the conversion of the failed verticalbanded gastroplasty patients to RY gastric bypass, which

TABLE 4. Five-Year Morbidity and Mortality

Condition/disease

Cohort

Relative Risk Reduction

P Value

BariatricSurgery Controls

n % n % Estimate 95% CI

Blood and blood-forming organs 4 0.39 41 0.72 0.54 0.19 1.50 0.230Cancer 21 2.03 487 8.49 0.24 0.17 0.39 0.001Cardiovascular and circulatory 49 4.73 1530 26.69 0.18 0.12 0.22 0.001Digestive 377 36.43 1414 24.66 1.48 1.42 1.78 0.001Endocrinological 98 9.47 1566 27.25 0.35 0.32 0.38 0.001Genitourinary 77 7.44 551 9.61 0.77 0.63 0.97 0.027Infectious diseases 90 8.70 2140 37.33 0.23 0.17 0.25 0.001Musculoskeletal 50 4.83 682 11.90 0.41 0.32 0.55 0.001Nervous system 25 2.42 228 3.98 0.61 0.44 0.93 0.010Psychiatric and mental 45 4.35 470 8.20 0.53 0.41 0.73 0.001Respiratory 28 2.71 651 11.36 0.24 0.17 0.36 0.001Skin 38 3.67 305 5.32 0.69 0.48 0.96 0.027Mortality 7 0.68 354 6.17 0.11 0.04 0.27 0.001

FIGURE 2. Survival by group (Kaplan Meier survival analysis).

Christou et al Annals of Surgery • Volume 240, Number 3, September 2004

© 2004 Lippincott Williams & Wilkins420

ORIGINAL ARTICLE

Surgery Decreases Long-term Mortality, Morbidity, andHealth Care Use in Morbidly Obese Patients

Nicolas V. Christou, MD, PhD, John S. Sampalis, PhD, Moishe Liberman, MD, Didier Look, MD,Stephane Auger, BSc, Alexander P.H. McLean, MD, and Lloyd D. MacLean MD, PhD

Objective: This study tested the hypothesis that weight-reduction(bariatric) surgery reduces long-term mortality in morbidly obesepatients.Background: Obesity is a significant cause of morbidity andmortality. The impact of surgically induced, long-term weight losson this mortality is unknown.Methods: We used an observational 2-cohort study. The treatmentcohort (n ! 1035) included patients having undergone bariatricsurgery at the McGill University Health Centre between 1986 and2002. The control group (n ! 5746) included age- and gender-matched severely obese patients who had not undergone weight-reduction surgery identified from the Quebec provincial health insur-ance database. Subjects with medical conditions (other then morbidobesity) at cohort-inception into the study were excluded. The cohortswere followed for a maximum of 5 years from inception.Results: The cohorts were well matched for age, gender, andduration of follow-up. Bariatric surgery resulted in significant re-duction in mean percent excess weight loss (67.1%, P " 0.001).Bariatric surgery patients had significant risk reductions for devel-oping cardiovascular, cancer, endocrine, infectious, psychiatric, andmental disorders compared with controls, with the exception ofhematologic (no difference) and digestive diseases (increased ratesin the bariatric cohort). The mortality rate in the bariatric surgerycohort was 0.68% compared with 6.17% in controls (relative risk0.11, 95% confidence interval 0.04–0.27), which translates to areduction in the relative risk of death by 89%.Conclusions: This study shows that weight-loss surgery signifi-cantly decreases overall mortality as well as the development of newhealth-related conditions in morbidly obese patients.

(Ann Surg 2004;240: 416–424)

In recent years, morbid obesity has emerged as a seriouspublic health threat. After smoking, it is the second leading

cause of preventable, premature death in the United States. Itis estimated that there are 400,000 deaths attributable toobesity in the United States each year.1 The World HealthOrganization has recognized an epidemic of obesity through-out most of the developed and developing world.2 Canadianadult obesity trends have grown during a 13-year period from5.6% in 1985 to 14.8% in 1998.

Obesity is associated with multiple complications andrelated comorbidities that lead to both physical and psycho-logic problems.3–6 Bariatric surgery has been shown to be aneffective method for producing weight loss in obese patientsin both the short and long term7–11 and to be more effectivethan dieting in producing sustained weight loss.12 To date,there has not been a population-based study demonstrating asignificant impact of surgically induced permanent weightloss on mortality and the prevention of comorbidity in severeobesity. The current study addresses these issues by compar-ing the outcomes in 2 cohorts of morbidly obese patients.

METHODS

Study DesignThis was an observational 2-cohort study that compared

the morbidity and mortality of a cohort of morbidly obesepatients treated with bariatric surgery at the McGill Univer-sity Health Centre (MUHC) to that of matched morbidlyobese controls who had not been treated surgically. Theinception time of the bariatric cohort was the time of admis-sion for surgery. The inception time for the control group wasthe date of surgery of their matched bariatric patients. Amaximum of 6 controls were identified for each bariatricsubject. The 2 cohorts were followed for a maximum of 5years. The MUHC Research Institute ethics board approvedthe study.

Identification of Study CohortsA total of 1118 patients underwent bariatric surgery for

the treatment of morbid obesity at the MUHC betweenJanuary 7, 1986, and June 8, 2002. The unique health insur-

From the Section of Bariatric Surgery, Division of General Surgery, Depart-ment of Surgery, McGill University, Montreal, Quebec, Canada.

Reprints: Nicolas V. Christou, MD, PhD, Room s9.30, 687 Pine Ave. W., Montreal,Quebec, Canada H3A1A1. E-mail: [email protected].

Copyright © 2004 by Lippincott Williams & WilkinsISSN: 0003-4932/04/24003-0416DOI: 10.1097/01.sla.0000137343.63376.19

Annals of Surgery • Volume 240, Number 3, September 2004416


Bariatric surgery reduces mortality


Bariatric surgery reduces health costs

AFer 2 years cost for society of lap surgery is lower than no surgery


Stop nega8ve aKtude!

•  Self inflicted -‐> no cure ?

•  1. Preven8ve measures in children remains very important.

•  2. Bariatric surgery is more than weight reduc8on. –  Prevents cardiovascular diseases –  Prevents cancer –  Treats diabetes –  Treats hypertension

•  3. Bariatric surgery -‐> Metabolic surgery! 7 16 sept 2010 Geneesk dagen Antwerpen

Laparoscopy in morbid obesity.

•  1/3 of pa8ents requiring laparoscopy are obese.

•  Bariatric surgery is now preferen8al laparoscopic.

•  Why is morbid obese laparoscopy difficult for the

– Anesthesiologist ? – Surgeon ?


16 sept 2010 Geneesk dagen Antwerpen 9

Surgical comments

•  S8ll a lot of complaints –  Pa8ent presses en s8ll the anesthe8st tell that the pa8ent is relaxed. (TOF 0) !

–  Some anesthe8sts can give be^er relaxa8on than others. Why?

–  I have no surgical workspace and the anesthe8st is not willing to do anything!

–  Other surgeon can work at lower pressures while I am not able to do this?

–  Pa8ent is breathing at end opera8on although recovery s8ll takes a long 8me!

Anesthesiologische vragen

•  Ik kan pa8ent onvoldoende beademen wegens hoge luchtwegdrukken.

•  Chirurg wil intra abdominale druk niet doen dalen.

•  Et CO2 loopt te hoog op. TV, freq reeds maximaal.

•  Sommige chirurgen klagen nooit, hebben geen spierrelaxa8e nodig, werken veel sneller,…

•  Locoregionale niet mogelijk


On the abdominal pressure volume rela8on

0 2 4 6 8

10 12 14 16 18

0 1 2 3

intr

a ab

dom

inal

pre

ssur

e m

mHg

!

intra abdominal volume Liter!

J Mulier, B Dillemans, M Crombach, C Missant, A Sels (2009) On the abdominal pressure volume rela7onship. The Internet Journal of Anesthesiology. 2009; 21: 1.

PV0 = 5

E = 4 mmHg/l

Higher insuffla8on pressures needed

Insufficient intra abdominal volume


Abdominal E and PV0

•  Measure the abdominal pressure volume rela8on in the op8mal posi8on. –  Inflate the abdomen to reach a volume of 3 L. Keep this

pressure constant. –  Measure three points (vol-‐pressure) and calculate E and

PV0.

•  Calculate the pressure to reach 3 L •  Set the inflator to this pressure.

  Simplified: Set at the pressure when a volume of 3 L is reached.


16 sept 2010 Geneesk dagen Antwerpen Mulier JP 2008

13


BMI effect on abdominal P/V rela8on

•  J Mulier ISPUB 2009 –  Pressure volume rela8on is linear

–  PV0 and E define each pa8ent

•  J Mulier IFSO 2007

16 sept 2010 Geneesk dagen Antwerpen

Waist to Hip ra8o (WHR)

•  Man normal WHR: 0,9 •  Woman normal WHR: 0,7

•  Android fat distribu8on – WHR > 0,8

•  Gynoid fat distribu8on – WHR < 0,8

15


Android versus Gynoid fat distribu8on has a different Elastance


Two types of android obesity

Intra visceral adiposity Extra visceral adiposity Subcutaneus fat is scant and Subcutaneus fat is thick and intra abdominal fat is thick and intra abdominal fat is scant.


Large intra visceral fat volume, or liver steatosis makes the rela8on non linear !

•  If the abdominal fascia is already circular instead of ellip8c –  No deforma8on possible

–  No radius decrease with increasing volume

18


Pig: High dose desfl sevo •  Zelfde spier relaxa8e effect sevo en desfl

•  data JPMulier 2009


20

E en PV0 determined by ?

factors PV0 PVO sig E E sig

Age Neg 0.828 Pos 0.003*

Length Neg 0.356 Neg 0.245

Body weigth Pos 0.012* Pos 0.294

Bmi neg 0.054 Neg 0.272

Sex Neg 0.596 Neg 0.536

Gravidity Neg 0.305 Neg 0.049*

Prev abd operation Neg 0.191 Neg 0.009*

Muscle relaxation Neg 0.001* Neg 0.376

* Sig p<0.05

•  Mulier Dillemans ESA 2007


NMB effect on E -‐ PV0

•  E or Compliance unchanged by NMB – E determined by fascia, size and shape

•  PV0 drops by NMB – = extra volume at same pressure


Is deep relaxa8on needed and possible?

•  Time between end pneumoperitoneum and end opera8on is very short: –  in 5 min from TOF 0/4 -‐¼ 8ll 90% –  is not possible with neos8gmine.

•  Sugammadex – TOF 0/4 8ll end pneumoperitoneum – Very deep NMB PTC < 5 is possible 8ll the end


23

Effect of deep muscle relaxa8on on IAP with constant IAV

•  Gradual pressure drop un8l flat line •  Max effect at TOF = 0/4 •  No need to drop un8l PTC = 0


24

Effect of deep muscle relaxa8on on abdominal PV loop

•  TOF > 90%

•  TOF = 0/4

•  TOF 0/4 and PTC < 5

Only leg flexion affects E in mmHg/L

E: 3,6 > E: 2,6 vol increase: 1100ml

J P Mulier, B Dillemans Impact of trunk posi8oning and leg flexion on the abdominal elastance during bariatric surgery. :Eur J Anesth 2008; 25, S44:234

Only table inclination affects PV0 in mmHg

PV0: 4,8 > 4,1 > 3,8 vol increase: 200ml 900 ml



How to change E : hip flexion

•  Mulier JP, Dillemans B Obes Surg 2009

Worst Best

airway pres in cmH20:

27,6 > 27,3 > 25,4 > 25 > 24,4

Effect of posi8on on airway pressure cmH2O

P decreases with an8 trendelenburg and leg flexion

J P Mulier, B Dillemans Impact of leg flexion and reverse trendelenburg on airway pressure during laparoscopic bariatric surgery. Obes Surg 2008; 18:444 27 16 sept 2010 Geneesk dagen Antwerpen

Volume instead of pressure controlled abdominal insufflation in morbid obese patients.

J P Mulier, B Dillemans Volume instead of pressure controlled abdominal insuffla8on in morbid obese pa8ents. Obes Surg 2007; 17:1000 28 16 sept 2010 Geneesk dagen Antwerpen


Why giving insufficient NMB? •  Rest relaxa8on is very anxious •  To prevent bad respira8on post op, low satura8on, high et CO2

•  Relaxa8on sufficient ended to allow neos8gmine to work –  TOF minimum one count

•  Be^er no neos8gmine as –  Bradycardia -‐ total AV block risico –  Bronchospasm (asthma8c pa8ents?) –  Vomi8ng and nausea post op

No reason now with Sugammadex (brideon)


Are surgeons right to be difficult?

•  Even with max NMB, abdomen can be under tension with insufficient space.

•  Other techniques are needed Abd infla8on volume at 15mmHg


Laparoscopy without muscle relaxants ?

•  Laparoscopy is possible without NMB if –  Abdominal compliance > 0,5 L/mmHg –  IAV > 4 L at 15 mmHg at start laparoscopy

•  Gravidity > 3 •  Previous mul8ple laparoscopies/laparotomies •  > 10 kg weight reduc8on •  No man with android fat distribu8on

–  AFer several hours abdominal compliance rises and

–  Sufficient deep sleep •  As pa8ent should not breath against ven8lator.

–  Pressure support ven8la8on •  Easier to prevent breathing against ven8lator


32

Begin – End of first laparoscopy

•  Abdominal compliance changes during pneumoperitoneum

•  Infla8on volume rises more than 1 liter!

•  No NMB needed at end of opera8on ?

One Hour Laparoscopy at 15 mmHg Elongates the Abdominal Wall Mulier IFSO 2009

Impact of laparoscopy depends on


33

0

0.5

1

1.5

2

2.5

3

•  J P Mulier, I Casier, K Verbeke, B Vanacker 2010 ESA

Vol increase at end lap


But if pa8ent breaths against ven8lator: Valsalva effect

•  Valsalva is an ac8ve muscle contrac8on different from breathing –  It increases the abdominal pressure to block inspira8on

•  Preventable by support ven8la8on

Peri opera8ve pain medica8on depends on Gravidity or previous laparoscopy

•  ASA 2010 JPMulier

0

10

20

30

40

50

60

BMI Piritramide Sufentanyl

G:0 lap:0

G>0 lap>0


Piritramide mg Sufentanyl ug Total peri opera8ve dose

Perfusalgan 2 gr/4 hours


Con8nuous NMB needed ?

•  Yes –  Larger surgical work-‐volume at lower pressures – Workspace some8mes remains insufficient making surgeons angry : try to do everything.

–  Prevent breathing against ven8lator –  At low pressures less structural damage and less post op pain?

•  No –  Abdominal compliance some8mes large enough – Work at higher intra abdominal pressure?

–  2 MAC inhala8on has same effect? –  Effect of posi8on and of 8me?


If Yes -‐> decurarisa8on needed

•  Only Bridion is able to do allow full muscle relaxa8on 8ll the end.

•  Use con8nuous infusion of Rocuronium (Esmeron) adapted to TOF measurements. –  Induc8on dose of 0,6 -‐ 1,2 mg/kg IBW – Con8nuous infusion of 50 mg/h -‐> …

Sugammadex Dose adapta8on? •  Sorgenfrei 2006 78 sec •  Vanacker 94 sec •  P Van Lancker T Bogaert J P Mulier •  BMI 44,5 2mg/kg sugammadex at T1 – T2 •  All pa8ent were full decurarised above 90% in max 6 minutes


0

50

100

150

200

250

300

350

IBW IBW + 20% IBW + 40%

7me to T4>0.9

8me to T4>0.9


Measure Depth of Blockade

•  Intense block: 16 mg/kg •  Deep block: 4 mg/kg •  Moderate block: 2 mg/kg •  Superficial block: 1 mg/kg + Neos8gmine? •  No block: 0 mg/kg

PTC 0 PTC ≥1

Intense block Deep block Moderate block

TOF count 0 TOF count 0 TOF count 1-3

Level of block

Response to TOF

Response to PTC

PTC, posttetanic count; TOF, train-of-four. Fuchs-Buder T et al. Acta Anaesthesiol Scand. 2007;51:789-808.

Posttetanic count

Twitch response

Twitch percentage

Superficial block TOF count 4

T1/T4 %


Immediate effects in morbid obese pa8ents of Bridion

•  Deep breaths possible –  Less lung collaps

•  Aurosal effect –  Like Amfetamine awakening –  Sudden muscle fiber s8mula8on gives aurosal

•  Pa8ent transfers him/her self in bed –  50 % of cases instead of only10%

•  Spontaneous movements easier –  Deep venous trombosis preven8on

•  No non invasive assist since introduc8on of sugammadex

Old method: rolling mat


Self in bed aFer Bridion?


JPM 9 9 2010 Anesthesie voor bariatrische heelk 43

Second ESPCOP Scien8fic mee8ng

Mul8disciplinarity

Pordenone, Italy 18 sept 2010

do#we#need#neuromuscular#blockers#...

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