Physiology of the abdominal pressure volume relation in

Physiology of the abdominal pressure volume relation in morbid obese patients. Impact on the treatment of morbid obese patients at the intensive care? J P Mulier, MD Physiology APVR and impact on ITE? 12 jan 2010 Sint Jan Brugge-Oostende www. publicationslist. org/jan. mulier

Why was this research needed? n Surgical complaints n n n Patient presses. Insufficient workspace in morbid obese patients. Request for extra dose, although full relaxation is given. High dose muscle relaxants does not work. Need to show the active impact of anesthesiology. n n Improving total outcome by helping to improve the surgical results. Transdisciplinary work Physiology APVR and impact on ITE? 12 jan 2010

Volume inflated at 15 mm. Hg with or without muscle relaxation. Large variation in abdominal volume n Muscle relaxation has variable effect! n Physiology APVR and impact on ITE? 12 jan 2010 JPMulier, B Dillemans ESA 2007

Description? n n n Measure the pressure volume relation Angle is compliance or elastance Section with Y axis is PV 0: pressure at zero volume P = 3, 30 V + 8, 40 mm. Hg Squared R = 0, 96 E : 3, 3 mm. Hg/L PV 0 : 8, 4 mm. Hg On the abdominal pressure volume relationship Physiology APVR and impact on ITE? 12 jan 2010 Mulier JP ISPUB 2009; 21: 1

Why linear ? n n n exceptional lineair ? Physical (not physiologic) explanation A balloon is never linear No organ has a linear relation Half balloon radius diminishes instead of rises with increasing volume Physiology APVR and impact on ITE? 12 jan 2010 JPMulier, ESA 2007, 3 AP 1

CT scan • Mulier J. P. , Coenegrachts CT analysis of the elastic deformation and elongation of the abdom wall during colon inflation for virtual coloscopy Eur J Anesthesia 2008 Suppl Physiology APVR and impact on ITE? 12 jan 2010

Muscle relaxation effect on PV 0 n E or Compliance no change n. E n is by fascia, size en shape determined PV 0 lower n Relaxants identical to 2 MAC Sevo or Desflu Physiology APVR and impact on ITE? 12 jan 2010 J Mulier IFSO Obes Surg 2008

P V loops JPMulier ASA 2008 Physiology APVR and impact on ITE? 12 jan 2010 JPMulier, ESA 2009

Effect of deep muscle relaxation on abdominal PV loop n n n TOF > 90% TOF = ¼ TOF 0/4 and PTC < 5 Physiology APVR and impact on ITE? 12 jan 2010

Patient with no effect of muscle relaxants No muscles in abd wall, diaphragm ? n Fully relaxed by other factors ? n § TOF > 90% § TOF = ¼ § TOF 0/4 and PTC < 5 Physiology APVR and impact on ITE? 12 jan 2010

Why sometimes no effect ? n Already total relaxed before n n Muscle and fascia in parallel: fascia takes all tension, further muscle relaxation no length increase. n n Diaphragm, rectus tension in length Muscle thin, in relaxation fascia not longer. n n Inhalation 2 MAC Rectus cross tension Expansion abdominal wall or shape change? Physiology APVR and impact on ITE? 12 jan 2010

Effect deep muscle relaxation on IAP with constant IAV n n n Gradueel druk daling tot vlakke lijn Max effect bij bereiken. TOF 0/4 Aan PTC 0 geen extra drukdaling TOF 4/4 Physiology APVR and impact on ITE? 12 jan 2010 TOF ¼ PTC 10 PTC 5 PTC 0

n Contraction shortens abdominal wall in two directions n Muscle direction n Perpendicular on muscle n No change in fascia elasticity n Curve n keeps same angle Shortening fascia has same effect as increase in intra abd volume Contraction Rest Relaxation n PV 0 increases Physiology APVR and impact on ITE? 12 jan 2010

Moderate, deep or very deep? TOF needed to measure n Diaphragm and vocal cords are most resistant to MR n No active contraction m sufficient passive relaxation n Diaphragm is never 100% blocked n n At PTC count zero ventilator can still be triggered! Physiology APVR and impact on ITE? 12 jan 2010

PSV prevent breathing against ventilator, is more physiologic n n n PSV is possible during deep muscle relaxation! Diaphragm is never total relaxed. Morfine stops PSV! PROFOUND MUSCLE RELAXATION DOES NOT DISTURB PRESSURE SUPPORT VENTILATION. Physiology APVR and impact on ITE? 12 jan 2010 Mulier J, Blacoe D PGA 2009

Is muscle relaxation needed ? n Gynecologic laparoscopy without curare is possible. n n Chassard D. Ann Fr Anesth Reanim. 1996; 15(7): 1013 -7 Only when compliance is very high Physiology APVR and impact on ITE? 12 jan 2010

Effect of valsalva: tegenademen n n Valsalva is an active muscle contraction different from breathing to increase the abdominal pressure Happens when patient reacts on Controlled Ventilation Physiology APVR and impact on ITE? 12 jan 2010

E and PV 0 determined by ? Factor: PV 0 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 Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier ESA 2007

BMI effect on abdominal P/V relation n J Mulier ISPUB 2009 n n Pressure volume relation is linear PV 0 and E define each patient Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier IFSO 2007

Waist to Hip ratio (WHR) Man normal WHR: 0, 9 n Woman normal WHR: 0, 7 n n Android fat distribution n WHR n > 0, 8 Gynoid fat distribution n WHR Physiology APVR and impact on ITE? 12 jan 2010 < 0, 8

Attractiveness in WHR from 4000 BC until 2000 AC 1, 5 1, 1 1, 5 Physiology APVR and impact on ITE? 12 jan 2010 0, 5 0, 7

WHR vs BMI Physiology APVR and impact on ITE? 12 jan 2010

Obesity type n Android Physiology APVR and impact on ITE? 12 jan 2010 vs Gynoid

Android versus Gynoid fat distribution has a different Elastance Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier 2009

Two types of android obesity Subcutaneus Fat Visceral fat Intra visceral adiposity Subcutaneus fat is scant and intra abdominal fat is thick and Physiology APVR and impact on ITE? 12 jan 2010 Extra visceral adiposity Subcutaneus fat is thick and intra abdominal fat is scant.

Large intra visceral fat volume, or liver steatosis makes the relation non linear ! n If the abdominal fascia is already circular instead of elliptic n n No deformation possible No radius decrease with increasing volume Physiology APVR and impact on ITE? 12 jan 2010

Metabolic syndrome: 3 of the 4 Diabetus Hypertension Dyslipidemia Visceral obesity Physiology APVR and impact on ITE? 12 jan 2010

What can we do to improve the abdominal physiology? Improve surgical workspace n Facilitate ventilation n Reduce mortality n n Methods available ? Physiology APVR and impact on ITE? 12 jan 2010

Table inclination changes PVO Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier IFSO 2009

Leg flexion lowers E Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier IFSO 2009

Lapararoscopy lowers E n n Mean IAP: 15, 4 +/- 1, 5 mm. Hg Mean pneumoperitoneum time: 59 +/- 19 minutes n J Mulier PGA 2009 Begin lap End lap IAV at 15 2. 85 +/0. 46 4. 83 +/0. 78 * Elastance 3. 32 +/0. 48 2. 17 +/0. 5 * PV 0 4. 89 +/1. 0 5. 7 +/0. 88 Physiology APVR and impact on ITE? 12 jan 2010 J P Mulier PGA 2009

The obese patient is a challenge for anaesthesia, if patient has an android shape with intra visceral fat. Physiology APVR and impact on ITE? 12 jan 2010

Impact on ICU? n Ventilation optimalisation n Who is at risk for abd compartment syndrome? n n n Beach chair position if difficult to breath, if higher intra abd pressures. Curarisation useful if higher intra abdominal pressure History of previous laparoscopy, laparatomy, multipara lowers risk on IACS CT abd circle versus ellips Post operative pain is stretching dependent n First laparoscopy is more painful Physiology APVR and impact on ITE? 12 jan 2010

n Ventilation improvement only in difficult to ventilate patients Physiology APVR and impact on ITE? 12 jan 2010

Who is at risk ? n Patients with large E n Never pregnant, never laparatomy, never laparoscopy, sport n Android obese person n Patients with high PV 0 n Intra abdominal fat, hepatomegaly n Android obese person Physiology APVR and impact on ITE? 12 jan 2010

How to measure E on ICU: Vol change is needed n Urine bladder compliance n n Stomach volume change n n Not accurate enough! Echo abd n n Leak – balloon insertion? Ventilatory measured abdominal compliance n n Bladder has its own compliance Hepatomegalie? CT abdomen n n ellips or circle! Android central fat in obesity. Physiology APVR and impact on ITE? 12 jan 2010

Physiology APVR and impact on ITE? 12 jan 2010

Physiology APVR and impact on ITE? 12 jan 2010

Become member of ESPCOP today Everyone has obese patients in the future Physiology APVR and impact on ITE? 12 jan 2010