BMI can we squeeze them BMI can we squeeze them in?in?

ObjectivesObjectives

Increasing prevalence of obesityIncreasing prevalence of obesity Definition and types of obesityDefinition and types of obesity Pathophysiology of obesityPathophysiology of obesity Effects on drug distribution and handlingEffects on drug distribution and handling Physical challenges of the bariatric patientPhysical challenges of the bariatric patient

Size of the problem!Size of the problem!

Growing epidemic in developed countriesGrowing epidemic in developed countries Estimated 250 million obese people worldwideEstimated 250 million obese people worldwide In the USA 66% of the adult population are overweight and In the USA 66% of the adult population are overweight and

make up 30% of ICU admissions.make up 30% of ICU admissions. Obesity is a global epidemic Obesity is a global epidemic

WHO estimates in 2002 there were 2.5 million weight WHO estimates in 2002 there were 2.5 million weight related deathsrelated deaths

Problem of social and psychological dimension that affects Problem of social and psychological dimension that affects all ages and socioeconomic groupsall ages and socioeconomic groups

Australia by 2010 predicted prevalence of BMI >30 kg/m2Australia by 2010 predicted prevalence of BMI >30 kg/m2 27.4% of males27.4% of males 29.1% of females29.1% of females

Quetelet IndexQuetelet Index

Category BMI range -Category BMI range -kg/mkg/m22

Starvation less than 14.9Starvation less than 14.9 Underweight from 15 to 18.4Underweight from 15 to 18.4 Normal from 18.5 to 24.9Normal from 18.5 to 24.9 Overweight from 25 to 29.9Overweight from 25 to 29.9 Obese from 30 to 39.9Obese from 30 to 39.9 Morbidly Obese greater than 40Morbidly Obese greater than 40

BMI DefinitionsBMI DefinitionsBMI (kg/mBMI (kg/m22)) DescriptorDescriptor <20<20 UnderweightUnderweight 20-24.920-24.9 IdealIdeal 25-29.925-29.9 OverweightOverweight 30-39.930-39.9 ObeseObese 40-49.940-49.9 Morbidly obeseMorbidly obese 50-59.950-59.9 Super obeseSuper obese 60-69.960-69.9 Super Super obeseSuper Super obese >70>70 Hyper obeseHyper obese

ObesityObesity

Waist circumference >102cm in Waist circumference >102cm in Males and >88cm in females Males and >88cm in females indicates high risk of metabolic and indicates high risk of metabolic and cardiovascular complicationscardiovascular complications

Risks of obesityRisks of obesity

SmokingSmoking Duration of obesity Duration of obesity

“obese years”“obese years” Fat distrubution Fat distrubution

Android “apple Android “apple shaped’’ shaped’’

Increased airway fatIncreased airway fat CVSCVS RespiratoryRespiratory

Gynacoid “pear Gynacoid “pear shaped”shaped”

Outcomes from ICUOutcomes from ICU

APACHE and SAPS scoring do not take BMI APACHE and SAPS scoring do not take BMI into account.into account.

Several studies looking at obesity and risk of Several studies looking at obesity and risk of death with conflicting results.death with conflicting results.

Two recent meta-analyses demonstrated no Two recent meta-analyses demonstrated no difference in mortality between critically ill obese difference in mortality between critically ill obese and those with a normal BMI.and those with a normal BMI.

There may even be an improved survival There may even be an improved survival ““The Obesity Survival Paradox”The Obesity Survival Paradox”

Causes of obesityCauses of obesity Genetic Genetic EnvironmentalEnvironmental PsychologicalPsychological SocialSocial

Control of appetite and satietyControl of appetite and satiety Lectin, adiponectin, insulin, ghrelin, peptide YYLectin, adiponectin, insulin, ghrelin, peptide YY Leptin satiety, decreases appetiteLeptin satiety, decreases appetite

Obese Obese increased leptin (produced by adipose cells)increased leptin (produced by adipose cells) Decreased sensitivity to leptinDecreased sensitivity to leptin

Pathophysiology of obesityPathophysiology of obesity

Type II diabetesType II diabetes HypertensionHypertension Heart disease and strokeHeart disease and stroke OsteoarthritisOsteoarthritis DyslipidaemiaDyslipidaemia Cancer (endometrial breast and colon)Cancer (endometrial breast and colon) Liver diseaseLiver disease Obesity hypoventilation syndromeObesity hypoventilation syndrome

Drug administration and kineticsDrug administration and kinetics

Increased body massIncreased body mass Fat distribution in organsFat distribution in organs Increased blood volumeIncreased blood volume Increased muscle massIncreased muscle mass Increased clearanceIncreased clearance Decreased water to lipid ratioDecreased water to lipid ratio

PharmacokineticsPharmacokinetics

Lipophilic drugs Total body weightLipophilic drugs Total body weight BenzodiazepenesBenzodiazepenes PropofolPropofol Fentanyl – loading dose TBW then IBWFentanyl – loading dose TBW then IBW

Hydrophobic drugsHydrophobic drugs Neuromuscular blockers IBWNeuromuscular blockers IBW Vancomycin TBWVancomycin TBW Gentamicin / ciprofloxacin IBW + fractionGentamicin / ciprofloxacin IBW + fraction

Increased renal and hepatic clearance Increased renal and hepatic clearance (increased blood flow)(increased blood flow)

Ideal body weightIdeal body weight

Mathematical conceptMathematical concept Brocca (French surgeon 1871)Brocca (French surgeon 1871) Wt (kg) = ht (cm) – 100 = ideal body wt Wt (kg) = ht (cm) – 100 = ideal body wt

+/- 15% for women and 10% for men+/- 15% for women and 10% for men ““Corrected” body weight = IBW + 40% Corrected” body weight = IBW + 40%

excessexcess

NutritionNutrition

Prone to protein malnutrition as a result of Prone to protein malnutrition as a result of metabolic stressmetabolic stress

Elevated basal insulin, supresses lipolysis Elevated basal insulin, supresses lipolysis leading to accelerated conversion of protein to leading to accelerated conversion of protein to glucoseglucose

Start feeding within 24 hours of admissionStart feeding within 24 hours of admission Most calories should be carbs and fat to prevent Most calories should be carbs and fat to prevent

FFA deficiencyFFA deficiency Hypo caloric feeding maybe beneficial Hypo caloric feeding maybe beneficial

Dickerson RN, Boschert KJ,Kudsk KA, Brown RO. Hypocaloric enteral tube feeding in critically ill obese Dickerson RN, Boschert KJ,Kudsk KA, Brown RO. Hypocaloric enteral tube feeding in critically ill obese pateints. Nutrition 2002: 18; 241-6pateints. Nutrition 2002: 18; 241-6

AirwayAirway

PositionPosition TongueTongue EquipmentEquipment Mouth openingMouth opening Short neckShort neck Neck circumferenceNeck circumference: 5% : 5%

chance difficult intubation if chance difficult intubation if > 40cm > 40cm but but 35% chance if 35% chance if >60cm! >60cm!

Best indicator of potential Best indicator of potential difficult airwaydifficult airway

STOPBANG risk of OSASTOPBANG risk of OSA

TracheostomyTracheostomy

Respiratory systemRespiratory system

VentilationVentilation Position Reverse Position Reverse

Trendelenburg, Trendelenburg, FRC decreases with FRC decreases with

increasing BMI, increasing BMI, increased A-a increased A-a gradient, gradient,

Rapidly desaturateRapidly desaturate

Respiratory systemRespiratory system

Restrictive lung diseaseRestrictive lung disease Decreased chest wall complianceDecreased chest wall compliance Diaphragm forced cephaladDiaphragm forced cephalad Decreased lung volumesDecreased lung volumes Accentuated by supine and Trendelenberg Accentuated by supine and Trendelenberg

positionspositions FRC may fall below closing capacityFRC may fall below closing capacity

Alveolar collapseAlveolar collapse Ventilation / perfusion mismatchVentilation / perfusion mismatch

Cardiovascular PathophysiologyCardiovascular Pathophysiology

For every 13.5 kg of fat gained:For every 13.5 kg of fat gained: 25 miles of neovascularization occurs 25 miles of neovascularization occurs Increased blood volumeIncreased blood volume Increased CO of 0.1 L/min for each kg of fat.Increased CO of 0.1 L/min for each kg of fat.

The blood volume and CO of a person weighing 170 The blood volume and CO of a person weighing 170 kg are twice that of a 70 kg personkg are twice that of a 70 kg person

Regional blood flows are normal, except in the Regional blood flows are normal, except in the splanchnic bed where it is increased 20%splanchnic bed where it is increased 20%

CardiovascularCardiovascular

HypertensiveHypertensive Difficult to measure BPDifficult to measure BP Difficult to measure saturationsDifficult to measure saturations Cardiopulmonary resuscitationCardiopulmonary resuscitation Pulmonary hypertension right ventricular Pulmonary hypertension right ventricular

failurefailure Fatty infiltration of the myocardiumFatty infiltration of the myocardium

Nutrition and metabolismNutrition and metabolism Malnourished group of patientsMalnourished group of patients Metabolic syndromeMetabolic syndrome

ObesityObesity Insulin resistanceInsulin resistance DyslipidaemiaDyslipidaemia HyperglycaemiaHyperglycaemia Proteolytic rather than lipolyticProteolytic rather than lipolytic

Feed regimesFeed regimes 15-20kcal/kg/day IBW15-20kcal/kg/day IBW Protein 1.5-2g/kg/day IBWProtein 1.5-2g/kg/day IBW Essential fatty acidsEssential fatty acids

Beauty is in the eye of Beauty is in the eye of the beholder.the beholder.

Optimal PositioningOptimal Positioning

Least beneficialLeast beneficial Supine, Trendelenburg, lithotomy, proneSupine, Trendelenburg, lithotomy, prone

Promote dyspnea, atelectasis, hypoxemiaPromote dyspnea, atelectasis, hypoxemia

Most beneficialMost beneficial Lateral decubitusLateral decubitus

Displaces the abdomen and allows greater diaphragm Displaces the abdomen and allows greater diaphragm excursionexcursion

303000-45-450 0 semirecumbant position semirecumbant position After gastric surgeryAfter gastric surgery

Positioning and RehabilitationPositioning and Rehabilitation

Back injuries to staff is a real and constant threat Back injuries to staff is a real and constant threat Scheduled positioning imperative:Scheduled positioning imperative:

Takes 5 staff to move patient, 3 staff if using a Takes 5 staff to move patient, 3 staff if using a specialized moving mattressspecialized moving mattress

Physical Therapist provides education related to Physical Therapist provides education related to correct body mechanics to prevent injury to staff correct body mechanics to prevent injury to staff and patientand patient

Physical AssessmentPhysical Assessment

BPBP: use thigh cuff or regular cuff on forearm: use thigh cuff or regular cuff on forearm Breath soundsBreath sounds: displace skin folds: displace skin folds Bowel soundsBowel sounds: girth measurements accurately : girth measurements accurately

identify distentionidentify distention HeartHeart: auscultate over L lateral chest when pt is : auscultate over L lateral chest when pt is

turned toward L sideturned toward L side ABGs more reliable that pulse oximeter due to ABGs more reliable that pulse oximeter due to

poor peripheral perfusionpoor peripheral perfusionHurst S et al (2004)Hurst S et al (2004)

Procedures and Diagnostic Procedures and Diagnostic TestingTesting

Before ordering & transporting patientBefore ordering & transporting patient Assure the diagnostic site and equipment can Assure the diagnostic site and equipment can

accommodate pts sizeaccommodate pts size Consult with the techs beforehandConsult with the techs beforehand Many recommend transport in patient’s bedMany recommend transport in patient’s bed Be aware that some elevators may not accommodate Be aware that some elevators may not accommodate

weight of bed, patient, equipment and caregiversweight of bed, patient, equipment and caregivers

Prevention of VTEPrevention of VTE

Pulmonary EmbolismPulmonary Embolism Morbid obesity is an independent risk factorMorbid obesity is an independent risk factor Primary prevention is key (Mobilization)Primary prevention is key (Mobilization) Obese patient excluded from trials on effective Obese patient excluded from trials on effective

prophylactic regimenprophylactic regimen LMWH Study: nonrandomized prospective study of LMWH Study: nonrandomized prospective study of

481 bariatric surgery pts (BMI> 50 kg/m2)481 bariatric surgery pts (BMI> 50 kg/m2) 40 mg q 12 hrs was superior to 30 mg q 12 hrs40 mg q 12 hrs was superior to 30 mg q 12 hrs No difference in bleeding events reportedNo difference in bleeding events reported

Sholten DJ et al (2002)Sholten DJ et al (2002)

IV heparin: weight based dosing, need frequent aPPT IV heparin: weight based dosing, need frequent aPPT monitoringmonitoring

Venous AccessVenous Access

Central linesCentral lines Obese patients have double the use and lines are in Obese patients have double the use and lines are in

longer than non-obese ptslonger than non-obese pts One study suggests no difference in mechanical One study suggests no difference in mechanical

insertion complication rate insertion complication rate El-Solh A et al (2001)El-Solh A et al (2001)

Switch to PICC lines as soon as possibleSwitch to PICC lines as soon as possible

Impact of Obesity in Impact of Obesity in mechanically ventilated patients: mechanically ventilated patients:

a prospective studya prospective study Intensive care medicine 2008 34:1991-1998Intensive care medicine 2008 34:1991-1998 French studyFrench study Measurements Measurements

Tracheal intubationTracheal intubation Catheter placementCatheter placement Nosocomial infectionsNosocomial infections Development of pressure ulcersDevelopment of pressure ulcers ICU and hospital outcomeICU and hospital outcome

ResultsResults

82 severely obese patients (mean BMI 42+/- 6 82 severely obese patients (mean BMI 42+/- 6 kg/mkg/m22))

124 non-obese patients (mean BMI 24 +/- 4 kg/m124 non-obese patients (mean BMI 24 +/- 4 kg/m22)) ICU course the same exceptICU course the same except

Difficulties during tracheal intubation (15 vs 6%)Difficulties during tracheal intubation (15 vs 6%) Post extubation stridor (15 vs 3%)Post extubation stridor (15 vs 3%) P<0.05P<0.05

Mortality rates (24 and 25%)Mortality rates (24 and 25%) No difference in risk-adjusted hospital mortalityNo difference in risk-adjusted hospital mortality

Obesity is associated with increased Obesity is associated with increased morbidity but not mortality in critically ill morbidity but not mortality in critically ill

patientspatients Intensive care medicine 2008 34:1999-2009Intensive care medicine 2008 34:1999-2009 Data from the SOAP studyData from the SOAP study ResultsResults

198 ICUs in 24 European countries198 ICUs in 24 European countries BMI available in 2878 pts (91%) of the 3147 SOAP study ptsBMI available in 2878 pts (91%) of the 3147 SOAP study pts 120 patients 4.2% underweight120 patients 4.2% underweight 1206 patients 41.9% normal BMI1206 patients 41.9% normal BMI 1047 patients 36.4% overweight1047 patients 36.4% overweight 424 patients 14.7% obese424 patients 14.7% obese 81 patients 2.8% very obese81 patients 2.8% very obese

ResultsResults Obese and very obese BMI>30Obese and very obese BMI>30

More frequent ICU acquired infectionsMore frequent ICU acquired infections Very obese BMI>40Very obese BMI>40

Trend towards longer ICU and hospital lengths of stayTrend towards longer ICU and hospital lengths of stay 4.1 (1.8-12.1) vs 3.1 (1.7-7.2) p=0.0564.1 (1.8-12.1) vs 3.1 (1.7-7.2) p=0.056 14.3 (8.4-27.4) vs 12.3 (5.1-24.4) p=0.07714.3 (8.4-27.4) vs 12.3 (5.1-24.4) p=0.077

No significant differences in mortality ratesNo significant differences in mortality rates None of the BMI categories was associated with an None of the BMI categories was associated with an

increased risk of 60-day in hospital deathincreased risk of 60-day in hospital death

Increasing risk of death with BMIIncreasing risk of death with BMI

ConclusionConclusion

The only difference in morbidity of obese The only difference in morbidity of obese patients who were mechanically ventilated patients who were mechanically ventilated was increased difficulty with intubation and was increased difficulty with intubation and higher incidence of post extubation stridor.higher incidence of post extubation stridor.

BMI did not significantly impact on BMI did not significantly impact on mortality in this mixed population of ICU mortality in this mixed population of ICU patientspatients

SummarySummary

Increasing prevalence of obesityIncreasing prevalence of obesity Definition and types of obesityDefinition and types of obesity Pathophysiology of obesityPathophysiology of obesity Effects on drug distribution and handlingEffects on drug distribution and handling Physical challenges of the bariatric patientPhysical challenges of the bariatric patient There really is no increase in mortality!There really is no increase in mortality!