Post operative pulmonary complications- summarised

1. Post operative pulmonary
complications
DR.MALAKA MUNASINGHE
REGISTRAR IN
ANAESTHESIOLOGY
12.05.2017

3. Overview
 Definition/ incidence and impact of postoperative pulmonary
complications( PPC)
 Pathophysiology- intraoperative
- postoperative factors
 Preoperative risk stratification – patient related factors
- procedure related factors
- laboratory data
 conclusion

4. Definition
 Any complication affecting the respiratory system after anaesthesia and surgery
 European joint task force -2015
perioperative clinical outcome (EPCO) definitions
 Respiratory infection/ respiratory failure/pleural
effusion/atelectasis/pneumothorax/ bronchospasm/ aspiration pneumonitis
 Pneumonia/ acute respiratory distress syndrome (ARDS)/ pulmonary embolus

5. Incidence
 major surgery - pulmonary complications more common than cardiac
complications
 <1 to 23%
 postoperative respiratory failure - most common pulmonary complication

6. Impact
 One fifth with PPC -die within 30 days of a major surgery
(0.2–3% without a PPC)
 Increased length of stay
 Incraesed health care cost

7. Pathophysiology
 INTRA-OPERATIVE CHANGES IN RESPIRATORY SYSTEM
 Reduced FRC- 15–20%
• Altered regional distribution of ventilation with IPPV and reduced cardiac
output- V/Q mismatch

8. • Atelectasis ( 75% patients receiving muscle paralysis)
- Direct compression of lung tissue
- Airway closure ( FRC < closing volume)
- Rapid absorption of gases from alveoli where the airways are narrowed or closed
- Increased atelectasis with higher FIO2
( FIO2 of 1.0, 0.8, or 0.6 results in 5.6, 1.3, and 0.2% atelectasis in cross
sectional CT IMAGES)

9. Postoperative respiratory pathophysiology
 Hypoxia is common
 Causes
- Airway obstruction
- Residual anaesthetic and opioid effect
- Hypercapnia
- Residual effects of NMBDs

10. - Residual effects of NMBDs
- conventional monitoring indicate adequate recovery
- impaired activity of genioglossus- airway obstruction or increased resistance
- Abnormal co-ordination of pharyngeal and upper oesophageal muscles -increased
risk of aspiration

11. Respiratory system changes ctd….
 Sputum retention - impairment of mucociliary transport
 Atelectasis – persisting on post op day 3
 lowest FRC value - 1–2 days after upper abdominal surgery
normal values after 5–7 days
 Impairment of ventilatory responses to hypercapnia and hypoxia lasting for few
weeks after surgery

12. Preoperative risk stratification
 used to identify patients at high risk of complications
 prospective, multicentre trials
1. ARISCAT (assess respiratory risk in surgical patients in Catalonia)-2010
 SpO2 <96%
 respiratory infection in the last month
 age
 preoperative anaemia (<10 g dl−1
 intrathoracic/upper abdominal surgery
 duration of procedure (>2 h)
 emergency surgery
(low, intermediate and high risk)

13.  PERISCOPE (prospective evaluation of a risk score for postoperative pulmonary
complications in Europe) -2015
- predict risk of postoperative respiratory failure
Seven variables
- low preoperative SpO2
- at least one preoperative respiratory symptom
- chronic liver disease
- congestive heart failure
- intrathoracic/upper abdominal surgery
- procedure >2 h
- emergency surgery

14. Risk factors for development of PPC
 PATIENT RELATED FACTORS
Non-modifiable
Age
Male sex
ASA ≥II
Functional dependence (frailty)
Acute respiratory infection (within
1 month)
Impaired cognition
Impaired sensorium
Cerebrovascular accident
Malignancy
Weight loss >10% (within 6 months)
Long-term steroid use
Prolonged hospitalization

15.  Modifiable
Smoking
COPD
Asthma
CHF
OSA
BMI <18.5 or > 40 kg m−2
Hypertension
Chronic liver disease
Renal failure
Ascites
Diabetes mellitus
Alcohol
GORD
Preoperative sepsis

16.  PROCEDURE RELATED FACTORS
Non-modifiable
Type of surgery
 upper abdominal
 AAA
 Thoracic
 Neurosurgery
 head and neck
 vascular
Emergency (vs elective)

17. Procedure related factors ctd…..
Duration of procedure
Re-operation
Multiple GA during admission
Modifiable
Mechanical ventilation strategy
GA (vs regional)
Long-acting NMBDs and TOF ratio <0.7 in PACU
Residual neuromuscular block
Intermediate-acting NMBDs with surgical time <2 h (not antagonized)
Neostigmine
Sugammadex with supraglottic airway
Failure to use peripheral nerve stimulator
Open abdominal surgery (vs laparoscopic)
Perioperative nasogastric tube
Intraoperative blood transfusion

18.  LABORATORY TESTING
Urea >7.5 mmol litre−1
Increased creatinine
Abnormal liver function tests
Low preoperative oxygen saturation
‘Positive cough test
Abnormal preoperative CXR
Preoperative anaemia (<100 g litre−1)
Low albumin
Predicted maximal oxygen uptake
FEV1:FVC <0.7 and FEV1 <80% of
predicted

19.  Preop ABG and Spirometry- not found to be effective in predicting out
comes
 NICE- these performed with the request of a senior anaesthetist for ASA 3
or above patient with a suspected or confirmed respiratory disease
 Preop CXR- if abnormal – predictive of PPC
NICE- not routinely recommend

20.  Preoperative SPO2- <96-91% compared with >96%-twice the risk of PPC
- <90%- ten times the risk of PPC
 Highly validated/ simple tool

21.  Smoking cessation
-American College of Surgeons National Surgical Quality Improvement Program
(NSQIP) database
- postoperative complications in current, previous (cessation >1 yr), and never
smokers undergoing major surgery
- PPC incidence reduces drastically from current to non-smokers
- PPC incidence increases with number of PACK YEARS.

22.  NICE- 2013
- perioperative smoking cessation recommendations
- pharmacological and behavioural support
- Cessation for >4 weeks reduces PPCs by 23%
for >8 weeks by 47%

23. Preoperative anaemia
 Patients with Hb <10 g/dl undergoing any type of surgery -three-fold increase in
the risk of a PPC
 The risk independently associated with autologous blood transfusions
 Anaemia should be corrected with other measures

24. GA vs RA
 Cochrane systematic review -significant reduction in postoperative pneumonia
although there was no difference in 30 day mortality

25. Intraoperative ventilation strategies
 low VT
 Application of PEEP
 Recruitment measures

26. Recruitment maneuvers and application of PEEP
Study Technique
Severgnini and colleagues (2013)
Initial setting: 7 ml kg−1 IBW, RR 6 min−1, PEEP 10 cm H2O, I:E ratio 3:1
VT increased in steps of 4 ml kg−1 IBW until plateau pressure
30 cm H2O for three breaths
Settings returned to original, with PEEP maintained at 10 cm H2O
Futier and colleagues (2013) CPAP 30 cm H2O for 30 s
Treschan and colleagues (2012)
Three manual bag ventilations with a maximal pressure of
before extubation
Weingarten and colleagues (2010)
Three-step increase in PEEP:
4–10 cm H2O for three breaths
10–15 cm H2O for three breaths
15–20 cm H2O for 10 breaths
PEEP reduced and maintained at 12 cm H2O
Repeated 30 and 60 min after the first RM and hourly thereafter

27. Ideal body weight
 Men: 50+0.91(centimetres of height−152.4)
 Women: 45.5+0.91(centimetres of height−152.4)

28. Low Vs High VT
 significant reduction in PPCs between low (< 8 ml kg−1) and high (>8 ml kg−1) VT
ventilation

29. Effect of PEEP on PPC
 Severgnini and colleagues
 56 patients undergoing open abdominal surgery of >2 h duration
 9 ml kg−1VT, zero PEEP and no RMs (standard ventilation)
VS
 7 ml kg−1, 10 cm H2O PEEP and an RM after induction, disconnection, and before
extubation (protective ventilation)

30.  Improved Pulmonary function (FVC and FEV1) and arterial oxygenation in air
 Reduced atelectasis on CXR
 Reduced ‘Clinical Pulmonary Infection Score’
 No alteration in haemodynamics in the protective ventilation group

31. Low PEEP vs High PEEP( 10cmH2O)
 PROVHILO study
- a non-significant risk reduction towards a low PEEP level
- haemodynamic compromise more common in the high-PEEP group requiring
more fluid and vasopressors

32. Post operative CPAP and nasal high-flow oxygen
 A Cochrane review in 2014 – Insufficient evidence to confirm a benefit of
postoperative CPAP after major abdominal surgery
 Post-cardiac surgery prophylactic CPAP (10 cm H2O for 6 h) has been shown to
reduce PPCs
 Prophylactic nasal high-flow oxygen may benefit high-risk cardiac patients with
respiratory co-morbidity

33. Neuromuscular blocking drugs and their reversal
 use of long-duration NMBDs, such as pancuronium, with a TOF ratio <0.7 after
extubation is a risk factor for developing a PPC
 dose-dependent increase in PPC development with the use of intermediate-
duration NMBDs
 Neostigmine is independently associated with PPCs (When neostigmine is
administered without a NMBD- impairment of genioglossus function and
pharyngeal muscle coordination and decreases in TOF ratio in peripheral muscles)

34.  Use of peripheral nerve stimulation in conjunction with neostigmine can reduce
residual block and PPCs
 Sugammadex- reduced PPCs
 Laryngospasm and negative pressure pulmonary oedema with early administration
of sugammadex in the presence of a supraglottic airway

35. Nasogastric tube
 A meta-analysis has shown increased rates of atelectasis and pneumonia with
routine use of NGTs
 Their use should be reserved only for symptom relief or specific surgical reasons

36. Preoperative physiotherapy
 A systematic review of 12 controlled trials - preoperative aerobic exercise and
inspiratory muscle training (IMT) reduces PPCs and LOS in patients undergoing
cardiac and abdominal surgery

37. Postoperative physiotherapy and mobilization
 I COUGH
- postoperative respiratory care programme
- reduces rates of pneumonia and unplanned re-intubation in general and vascular
patients
- Incentive spirometry
- Deep breathe and cough every 2 h post op
- Head of the bed elevated >30°
- Mobilization three times a day
- Oral hygiene

38.  Epidural analgesia
- Reduced opioid consumption and better analgesia
- improves respiratory function
- reduces rates of pneumonia, postoperative ventilation, and unplanned re-intubation

39. Conclusion
 Postoperative pulmonary complications are common
 Many scoring systems to quantify PPC risk- clinically too complex
 Preoperative investigations( except SpO2 on air) - poor predictors of
development a PPC
 Preoperative cessation of smoking and correction of severe anaemia- improve
PPCs
 RA more favorable than GA
 GA- avoid NDMBs/ Lung protective ventilation with low VT/ low or moderate
PEEP/ Recruitment maneuvers
 Physiotherapy and oral hygiene- important in prevention of PPCs

40. THANK YOU!