Respiratory Dysfunction

Naisan GarrawayNaisan Garraway

Najib AyasNajib Ayas

The Case

69 yr old male with a 3-day history of 69 yr old male with a 3-day history of worsening SOB and increase use of his worsening SOB and increase use of his puffers. He denies chest pain. He also puffers. He denies chest pain. He also describes a productive cough with green describes a productive cough with green sputum. He has a known history of COPD sputum. He has a known history of COPD and quit smoking 1 month ago but had a 40-and quit smoking 1 month ago but had a 40-pack year history. He has had multiple pack year history. He has had multiple admissions for COPD exacerbations but admissions for COPD exacerbations but never intubated.never intubated.

The case

His past history is His past history is significant for Type II significant for Type II DM diet controlled, DM diet controlled, HTN, anterior resection HTN, anterior resection 5 yrs ago for 5 yrs ago for diverticulitis and a large diverticulitis and a large incisional hernia, which incisional hernia, which he is booked for repair he is booked for repair in 2 monthsin 2 months

The case

His meds include: Atrovent 4 puffs QID, His meds include: Atrovent 4 puffs QID, Ventolin 2 puffs QID, Cipro (he bought in Ventolin 2 puffs QID, Cipro (he bought in Mexico) prn, ECASA 81 mg, Ramipril 5 Mexico) prn, ECASA 81 mg, Ramipril 5 mg OD, Cold-FX (during the winter mg OD, Cold-FX (during the winter months)months)

He is allergic to Penicillin (anaphylaxis)He is allergic to Penicillin (anaphylaxis)

The Case

He lives with his wife and has a son in He lives with his wife and has a son in Medical School in Scotland. He quit Medical School in Scotland. He quit smoking 1 month ago and drinks 1-2 beer a smoking 1 month ago and drinks 1-2 beer a week.week.

In the ER

He was seen by the ER doc and was noted He was seen by the ER doc and was noted to be alert, SOB with a RR of 20 but could to be alert, SOB with a RR of 20 but could speak 3-5 word sentences, audible wheezes speak 3-5 word sentences, audible wheezes bilaterally, no peripheral edema, unable to bilaterally, no peripheral edema, unable to see JVP, no abdominal pain, obvious see JVP, no abdominal pain, obvious reducible incisional hernia. BP 150/90, HR reducible incisional hernia. BP 150/90, HR 120, and temp 37.5120, and temp 37.5

In the ER

showed WBC 14.8, Hb 140, Plts 400 showed WBC 14.8, Hb 140, Plts 400 normal coags. Lytes were Na 138, K 3.5, normal coags. Lytes were Na 138, K 3.5, Cl 100, CO2 35, Creat 160, and BUN 12.Cl 100, CO2 35, Creat 160, and BUN 12.

An ECG showed sinus tachy with poor R An ECG showed sinus tachy with poor R wave progression in the lateral leads. A wave progression in the lateral leads. A CXR showed hyperinflation with possible CXR showed hyperinflation with possible “streaking” in the RLL“streaking” in the RLL

CXR

In ER

An IV was started and he was given nebs of An IV was started and he was given nebs of Atrovent and Ventolin. 100 mg Atrovent and Ventolin. 100 mg hydrocortisone was given IV. The CTU Snr hydrocortisone was given IV. The CTU Snr was consulted and said would be right there was consulted and said would be right there but was dealing with a septic patient on the but was dealing with a septic patient on the ward.ward.

Later that day

2 hours later the patient was assessed by CTU and 2 hours later the patient was assessed by CTU and was found to be obtunded but would rouse to a was found to be obtunded but would rouse to a loud voices. His BP was 140/81, HR 130 regular, loud voices. His BP was 140/81, HR 130 regular, RR 10, temp 37.8, and a sat of 88%RR 10, temp 37.8, and a sat of 88%

An ABG was done stat: 7.15/75/104.8/36. An ABG was done stat: 7.15/75/104.8/36. You get the call just having resuscitated a septic You get the call just having resuscitated a septic

CTU patient on the ward, to get down to the ER CTU patient on the ward, to get down to the ER ASAPASAP

Assessment

As you get there your keen Jr resident has As you get there your keen Jr resident has arrived first and tells you the story.arrived first and tells you the story.

1. What is the differential diagnosis?1. What is the differential diagnosis?

GordGord

Hypercapnic Respiratory Failure

Chronic obstructive pulmonary diseaseChronic obstructive pulmonary disease EmphysemaEmphysema Chronic bronchitisChronic bronchitis

Neuromuscular disordersNeuromuscular disorders Amyotrophic lateral sclerosisAmyotrophic lateral sclerosis Muscular dystrophyMuscular dystrophy Diaphragm paralysisDiaphragm paralysis Guillain-Barré syndromeGuillain-Barré syndrome Myasthenia gravisMyasthenia gravis

Hypercapnic Respiratory Failure

Chest wall deformitiesChest wall deformities KyphoscoliosisKyphoscoliosis FibrothoraxFibrothorax ThoracoplastyThoracoplasty

Central respiratory drive depressionCentral respiratory drive depression Drugs - Narcotics, benzodiazepines, barbituratesDrugs - Narcotics, benzodiazepines, barbiturates Neurologic disorders - Encephalitis, brainstem Neurologic disorders - Encephalitis, brainstem

disease, traumadisease, trauma Primary alveolar hypoventilationPrimary alveolar hypoventilation

Obesity hypoventilation syndromeObesity hypoventilation syndrome

MI/CHFMI/CHF PEPE

Pulmonary Embolism in Patients with Chronic Obstructive Pulmonary Disease

Ann Intern Med. 2006;144:390-396.

Showed a 25% prevalence of PE in patients with COPD hospitalized for severe exacerbation of unknown origin.

Clinical factors associated with PE were previous thromboembolic disease, malignancy, and decrease in PaCO2 of at least 5 mm Hg

BiPAP

You notice the RT is preparing the BiPAP You notice the RT is preparing the BiPAP ventilator.ventilator.

2. What is the role of BiPAP in COPD 2. What is the role of BiPAP in COPD exacerbation/acute respiratory failure?exacerbation/acute respiratory failure?

GordGord

NIPPV

Two meta-analysis found that patients randomized to receive NIPPV had a statistically significant decrease in the need for invasive mechanical ventilation and in the risk of death

Keenan SP, et al: Effect of noninvasive positive pressure ventilation on mortality in patients admitted with acute respiratory failure: a meta-analysis. Crit Care Med 1997.

Thys F, et al: Noninvasive ventilation for acute respiratory failure: a prospective randomized placebo-controlled trial. Eur Respir J 2002

NIPPV

Exacerbations of COPD with rapid clinical deterioration should be considered candidates for NIPPV

International consensus conferences in intensive care medicine: noninvasive positive pressure ventilation in acute respiratory failure. Am J Respir Crit Care Med 2001, 163:283–291.

NIPPV

Noninvasive ventilation in acute respiratory failure Nicholas S. Hill, et al; Crit Care Med 2007 Vol. 35,

Review of the literature supports that an initial trial with NIV is not deleterious, even in severely ill COPD patients ( eg pH <7.2)

(Conti et al 2002, Squadrone et al 2004) The “scant & conflicting data” suggests a

cautious trial of NIV in COPD pts with severe pneumonia is warranted.

Predict failure?

Sinuff et all Chest2003;123:2062-73

Review by Peñuelas et al. CMAJ 2007;177(10):1211-8

Obtunded Patient

3. Is there a role for NIPPV in the obtunded 3. Is there a role for NIPPV in the obtunded hypercarbic COPD patient?hypercarbic COPD patient?

GordGord

Noninvasive Positive-PressureVentilation To Treat Hypercapnic ComaSecondary to Respiratory FailureGumersindo Go´nzalez Dý´az,et al CHEST 2005; 127:952–960 The randomized studies excluded pts with The randomized studies excluded pts with

decreased LOCdecreased LOC Concern of aspiration riskConcern of aspiration risk International consensus

conference considered GCS <10 as contraindication

Never evaluated prospectively

Decreased LOC

Prospective, observational study between January 1, 1997, and May 31, 2002

Patients with GCS score <8 and CO2 retention formed one group, and those without coma served as a comparison group.

Excluded if another cause for LOC was found

Decreased LOC

Total of 958 pts started NIPPVTotal of 958 pts started NIPPV 95 (10.1%) had GCS scores on

admission <8 NIPPV success was similar in both

groups hospital mortality was not

significantly different

Outcomes

Conclusions for Coma

Coma should no longer be considered a contraindication to NPPV therapy.

NIPPV in Patients With Acute Exacerbations of COPD and Varying Levels of ConsciousnessScala, et al; CHEST 2005; 128:1657–1666 A 5-year case-control study with a

prospective data collection. Study confirms that NPPV may be

successfully applied to patients experiencing COPD exacerbations with milder ALCs, the rate of failure in patients with severely ALCs (ie, Kelly score > 3) is higher, though better than expected, so that an initial attempt with NPPV may be performed

Ventilation

You decide to intubate the patient instead and it You decide to intubate the patient instead and it goes ahead smoothly. Your medical student said goes ahead smoothly. Your medical student said he had heard these patients can get auto peep and he had heard these patients can get auto peep and that it can be BAD!that it can be BAD!

4. What would be your initial ventilator settings 4. What would be your initial ventilator settings including what measures can be done to minimize including what measures can be done to minimize auto peep in the ventilated COPD patient?auto peep in the ventilated COPD patient?

YoanYoan

Goals for COPD patients

Adequate patient monitoringAdequate patient monitoring Optimize ventilator settings to minimize Optimize ventilator settings to minimize

excessive work of breathingexcessive work of breathing Assure SynchronyAssure Synchrony Detect auto-PEEP and prevent barotraumaDetect auto-PEEP and prevent barotrauma Prevent further respiratory muscle atrophyPrevent further respiratory muscle atrophy Intubate using the widest diameter ET tube Intubate using the widest diameter ET tube

possible (R = 8nl / possible (R = 8nl / ππr r 44))

Mechanical Ventilation

Mode?Mode? Volumes/Pressures?Volumes/Pressures? Flow Rate?Flow Rate? RR?RR? pH?pH? I:E ratio?I:E ratio? PEEP?PEEP? FiO2FiO2

Auto-PEEP

When the expiratory time is not long enough to allow exhalation of all tidal volume auto-PEEP is generated.

Airway Pressures

PEEPi + PEEPe

Ranieri et al Eur Respir J, 1996, 9, 1283–1292

The Unit

The patient is brought up to “The Unit” and The patient is brought up to “The Unit” and your Jr has finished the admission orders your Jr has finished the admission orders and wants to review them with you.and wants to review them with you.

5. What treatments do you want to ensure 5. What treatments do you want to ensure the patient receives?the patient receives?

YoanYoan

Orders

Sedation?Sedation? Bronchodilators?Bronchodilators? Steroids?Steroids? Antibiotics?Antibiotics? Nutrition?Nutrition? Insulin?Insulin? Heliox?Heliox? Further investigations?Further investigations?

Weaning

After a few days, some improvement is seen. His After a few days, some improvement is seen. His FiO2 requirements are 30% and his lungs sound FiO2 requirements are 30% and his lungs sound much clearer. He has also been weaned down to much clearer. He has also been weaned down to pressure support. The RT mentioned the weaning pressure support. The RT mentioned the weaning indices for the day with a PO2/FiO2=300, RSBI of indices for the day with a PO2/FiO2=300, RSBI of 120. Your medical student looks confused and asks:120. Your medical student looks confused and asks:

6. What are weaning indices and what is the 6. What are weaning indices and what is the evidence for their use?evidence for their use?

YoanYoan

RSBI

This is f/VTThis is f/VT Yang, KL, Tobin, MJ (1991) A prospective Yang, KL, Tobin, MJ (1991) A prospective

study of indexes predicting the outcome of trials study of indexes predicting the outcome of trials of weaning from mechanical ventilation. of weaning from mechanical ventilation. N Engl N Engl J MedJ Med 324324,1445-1430,1445-1430

Shown to be predictive of extubation if Shown to be predictive of extubation if <<105105

RSBI

Frutos-Vivar, et al 2006;130;1664-1671 Chest

Risk Factors for Extubation Failure in

Patients Following a Successful

Spontaneous Breathing Trial

Spontaneous Breathing Trial

ELY et al; N Engl J Med 1996;335:1864-9.)

RCT of 300 vented pts in ICU&CSICURCT of 300 vented pts in ICU&CSICU All pts screened daily for PaO2/FiO2>200, All pts screened daily for PaO2/FiO2>200,

PEEPPEEP<<5, f/Vt <105, good cough, no 5, f/Vt <105, good cough, no pressorspressors

SBT

Intervention group then underwent SBT for Intervention group then underwent SBT for 2 hours that morning2 hours that morning

If passed a note was left on the chartIf passed a note was left on the chart Controls only had the daily assessmentControls only had the daily assessment

SBT results

Asynchrony

Five days later, your patient is still requiring a Five days later, your patient is still requiring a PSV of 10 and PEEP 5. The RT notes some PSV of 10 and PEEP 5. The RT notes some asynchrony as well. The bright Jr resident pipes asynchrony as well. The bright Jr resident pipes up and says he heard about a different form of up and says he heard about a different form of ventilation called PAV that might help with this.ventilation called PAV that might help with this.

7. What is PAV and how does it work?7. What is PAV and how does it work?

SteveSteve

PAV (Proportional Assist Ventilation)

ventilator amplifies the patient's

inspiratory effort without any preselected target volume or

pressure Aim is to allow the patient to attain

their own ventilation and breathing patternYounes M. Proportional assist ventilation, a new approach to

ventilatory support. Am Rev Respir Dis 1992;145:114–20

PSV vs PAV

Varelmann, et al; Crit Care Med 2005; 33:1968 –1975)

12 pts in randomized clinical crossover Increasing vent demand by adding

dead space Cardiorespiratory, ventilatory, and

work of breathing variables were assessed

Results No major differences in

cardiorespiratory function between dynamic and constant inspiratory pressure assistance.

PAV

8. Is there evidence it helps with patient 8. Is there evidence it helps with patient vent asynchrony?vent asynchrony?

SteveSteve

Giannouli, et al. Response of ventilator dependent patients to different levels of pressure support and proportional assist. Am J Respir Crit Care Med. 1999;159:1716 –1725.

found lower rates of ineffective triggering with PAV than with PSV, because tidal volume was smaller at high levels of assistance and because ventilator insufflation time was limited

Asynchrony

9. What other techniques can be used to 9. What other techniques can be used to decrease asynchrony?decrease asynchrony?

SteveSteve

Adjusting the Inspiratory Trigger Adjusting PEEP Adjusting the Pressure Support

Level Increasing the expiratory trigger (%

inspiratory flow) Neurally adjusted ventilatory assist

(NAVA)

VIDD

After 10 days in the unit the patient is still unable After 10 days in the unit the patient is still unable to fully wean off the ventilator. During rounds to fully wean off the ventilator. During rounds your great and mighty staff asks you:your great and mighty staff asks you:

10. What is ventilator induced diaphragm 10. What is ventilator induced diaphragm dysfunction-VIDD and how does it effect dysfunction-VIDD and how does it effect weaning?weaning?

ScottScott

VIDD

a loss of diaphragmatic force-generating capacity that is specifically related to the use of mechanical ventilation.

Inactivity of diaphragm during MV

VIDD

VIDD is a diagnosis of exclusion based on (1) an appropriate clinical history of

having undergone a period of controlled mechanical ventilation (CMV), and

(2) other possible causes of diaphragmatic weakness having been sought and ruled out

Atrophy, oxidative stress, myofibrillar disruption, and various remodeling responses within diaphragm muscle fibers

Animal studies suggest that the onset of VIDD during CMV is rapid

Minimize non-spont vent, steroids and maximize nutrition

antioxidants?

Tracheostomy

She then asks you if we should consult for a She then asks you if we should consult for a trach in this patient?trach in this patient?

11. When is the best timing for a 11. When is the best timing for a tracheostomy and does it reduce ICU length tracheostomy and does it reduce ICU length of stay?of stay?

ScottScott

Trach Timing

lack of adequately sized, randomized, prospective controlled studies

most recommendations are based on consensus opinions of clinical experts

Trach

Indications for tracheostomy include failure of extubation, upper airway obstruction, airway protection and airway

access for secretion removal, avoidance of serious

oropharyngeal and laryngeal injury from prolonged translaryngeal intubation

MacIntyre NR, Cook DJ, Ely EW Jr, et al.Chest 2001; 120 (6 Suppl):375S–395S.

ACCP guidelines suggest that tracheostomy should be considered after an initial period of stabilization on the ventilator (generally, within 3–7 days), when it becomes apparent that the patient will require prolonged ventilator assistance

Groves and Durbin Jr,Current Opinion in Critical Care 2007, 13:90–97

Review of literature on trachsReview of literature on trachs a number of retrospective studies

and a single prospective study have shed some light on timing of trach

Most reports favor the performance of tracheostomy within 10 days of respiratory failure

Summary of Trials

Sleep

The nurse also mentions the patient has The nurse also mentions the patient has been having difficulty sleeping most nights been having difficulty sleeping most nights (who doesn’t).(who doesn’t).

12. What is the impact of ventilator 12. What is the impact of ventilator settings on sleep patterns?settings on sleep patterns?

ScottScott

Parthasarathy; Am J Respir Crit Care Med Vol 166. pp 1423–1429, 2002

performed polysomnography on 11 criti- cally ill patients

examined whether the presence of backup rate on assist-control ventilation would decrease apnea-related arousals and improve sleep quality.

patients receiving mechanical ventilation have severely fragmented sleep

Sleep

the number of arousals and awakenings, was greater during pressure support than during assist-control ventilation: 79+7 versus 54+7 events per hour (p=0.02)

6 pts had central apneic episodes on PSV addition of dead space produced a mean

increase in end-tidal CO2 of 4.3 mm Hg, which resulted in a decrease in the frequency of central apneas

PAV vs PSVin Sleep

Bosma, et al; Crit Care Med 2007; 35:1048–1054

13 pts in crossover study13 pts in crossover study Overall sleep quality was significantly

improved on proportional assist ventilation (p < .05) due to the combined effect of fewer arousals and awakenings per hour

(3.5 vs. 5.5), and greater rapid eye movement (9% vs.

4%) and slow wave sleep(3% vs. 1% )

Patient-ventilator asynchronies per hour were lower with PAV than with PSV (24 vs. 53 ; p =.02) and correlated with the number of arousals per hour (RR =.65, p=.0001).

BiPAP and re-intubation

The next day the patient is on PSV 6 and PEEP of The next day the patient is on PSV 6 and PEEP of 5, is alert, afebrile, and has and passed his SBT. 5, is alert, afebrile, and has and passed his SBT. You feels it is time to pull the tube. 1 hour later, You feels it is time to pull the tube. 1 hour later, the patient becomes tachypneic and looks like he the patient becomes tachypneic and looks like he might fail extubation. Your very astute Jr said he might fail extubation. Your very astute Jr said he has read something about using BiPAP to prevent has read something about using BiPAP to prevent re-intubation.re-intubation.

13. What is the evidence to use BiPAP to 13. What is the evidence to use BiPAP to extubate/prevent re-intubation?extubate/prevent re-intubation?

DaveDave

NIPPV and Extubation

Keenan, et al; JAMA. 2002;287:3238-3244

RCT 81 patients who required ventilatory

support for more than 2 days and who developed respiratory distress within 48 hours of extubation.

Stnd therapy vs NIPPV+Stnd therapyStnd therapy vs NIPPV+Stnd therapy

Results

there was no difference in the rate of reintubation (72% vs 69%; relative risk, 1.04; 95% confidence interval, 0.78-1.38) or hospital mortality (31% for both groups; relative risk, 0.99; 95% confidence interval, 0.52-1.91).

Pts with COPD were excluded after 1 year because they thought it was unethical due to strong established literature supporting the use of NPPV for COPD exacerbations

NIPPV for Respiratory Failure after ExtubationEsteban, ET AL; N Engl J Med 2004;350:2452-60.

Multicenter, randomized trial Electively extubated after

mechanical ventilation and who had respiratory failure within 48 hours

There was no difference found (rate of reintubation, 48% in both groups; RR in the NIPPV group, 0.99; 95 percent CI, 0.76 to 1.30).

Rate of death in the intensive care unit was higher in the NIPPVgroup (25% vs. 14%; RR 1.78; 95 percent confidence interval, 1.03 to 3.20; P=0.048)

Likely due to increase time to re-intubation

Only 10% had COPD

Noninvasive positive-pressure ventilation in acuterespiratory failurePeñuelas et al, CMAJ 2007;177(10):1211-8

Review of literature the early use of NIPPV can prevent

respiratory failure after extubation and decrease the need for reintubation.

further studies that better define the population of patients at risk for respiratory failure after extubation may be necessary.

Prognosis

The patient does well and only requires The patient does well and only requires BiPAP for 12 hours. Your medical student BiPAP for 12 hours. Your medical student then asks:then asks:

14. What is the short and long-term 14. What is the short and long-term prognosis for a person with COPD who has prognosis for a person with COPD who has required mechanical ventilation?required mechanical ventilation?

DaveDave

Exacerbation of COPD: A Retrospective StudyIn-Hospital and 5-Year Mortality of Patients Treated in the ICU for Acute Chua Ai-Ping, et al; Chest 2005;128;518-524

Retrospective cohort study of 57 patients More than 90% of patients required

intubation The in-hospital mortality rate for the entire

cohort was 24.5%. mortality rates at 6 months and 1, 3, and 5

years were 39.0%, 42.7%, 61.2%, and 75.9%,

median survival time for all patients was 26 months.

Outcome

3-month mortality rate after ICU discharge was 11%.

only IBW predicted three-month survival rate

Vitacca, et al; CHEST 2005

Hospital mortality 15% (predicted 30%)Hospital mortality 15% (predicted 30%) Incidence of sepsis and number of organ failures Incidence of sepsis and number of organ failures

were higher in non-survivorswere higher in non-survivorsAfessa et al, Crit Care Med 2002Afessa et al, Crit Care Med 2002

Lung Reduction Surgery

The patient’s son arrives from Scotland and thanks The patient’s son arrives from Scotland and thanks you all for the wonderful care of his father. He you all for the wonderful care of his father. He then states that he has been reading on Lung then states that he has been reading on Lung Volume Reduction Surgery and wonders if it Volume Reduction Surgery and wonders if it would help his father.would help his father.

15. What is LVRS and is there evidence of 15. What is LVRS and is there evidence of benefit in COPD?benefit in COPD?

DaveDave

LVRS

•First introduced by Brantigan in 1957Brantigan, A surgical approach to pulmonary emphysema. Am Rev Respir Dis 1959; 80:194.

A randomized trial comparing lung-volume-reduction surgery with medical therapy for severe emphysema.Fishman et al, N Engl J Med 2003 May 22;348(21):2059-73

1218 pts with severe emphysema 1218 pts with severe emphysema underwent pulmonary rehab and were underwent pulmonary rehab and were randomly assigned to LVRS or to receive randomly assigned to LVRS or to receive continued medical treatmentcontinued medical treatment

Overall, surgery increases the chance of Overall, surgery increases the chance of improved exercise capacity but did not improved exercise capacity but did not confer a survival advantage over medical confer a survival advantage over medical therapytherapy

There was a survival advantage for There was a survival advantage for patients with both predominantly upper-patients with both predominantly upper-lobe emphysema and low base-line lobe emphysema and low base-line exercise capacity.exercise capacity.

The Effect of Lung Volume Reduction Surgery onChronic Obstructive Pulmonary Disease ExacerbationsWashko et al; Am J Respir Crit Care Med Vol 177. pp 164–169, 2008

To examine the effect, and mechanism of potential benefit, of LVRS on COPD exacerbations by comparing the medical and surgical cohorts of the National Emphysema Treatment Trial (NETT).

LVRS

no difference in exacerbation rate or time to first exacerbation between the medical and surgical cohorts during the year before study randomization

Post randomization, the surgical cohort experienced an approximate 30% reduction in exacerbation frequency(P=0.0005)

LVRS increased the time to first exacerbation in both subjects with and without a prior history of exacerbations (P=0.0002 and P=0.0001, respectively)

Effect of Bronchoscopic Lung Volume Reduction on Dynamic Hyperinflation and Exercise in EmphysemaNicholas, et al; Am J Respir Crit Care Med Vol 171

Endobronchial valve placement can improve lung volumes and gas transfer in patients with chronic obstructive pulmonary disease and prolong exercise time by reducing dynamic hyperinflation.

Bonus Time

Bonus questions: 1. Is there any evidence Bonus questions: 1. Is there any evidence that Cold-FX works?that Cold-FX works?

2. Should this patient have his large 2. Should this patient have his large ventral hernia repaired in the future and if ventral hernia repaired in the future and if so, using what technique?so, using what technique?

Hernia Repair

Factors to considerFactors to consider Size of hernia and risk of incarcerationSize of hernia and risk of incarceration Overall health of patientOverall health of patient Lap vs OpenLap vs Open