POSTOPERATIVE PULMONARY COMPLICATIONS AND ACUTE RESPIRATORY DISTRESS SYNDROME -BETTER PREVENT THEN TREAT.

In parallel with increasing number, duration and extensiveness of surgical interventions, postoperative pulmonary complications (PPC) and acute respiratory distress syndrome (ARDS) remain the major challenges for anesthesiologists and surgical ICU physicians. PPC and ARDS have multiple risk factors that should be recognized early and modifed within the appropriate "time window ". Today we possess reliable models (ARISCAT LIPS, EALI etc.) to predict the risk of non-infectious (hypoxemia, atelectases, pleuritis) and infectious PPC (postoperative pneumonia). The bundle of primaty and secondary prevention strategies is available and can be implemented both in the perioperative settings and in the ICU in patients at risk of PPC and ARDS. The prophylactic approach is realized as a bundle of strategies presented in "Checklist for Lung Injury Prevention" (CLIP). The bundle of preventive protective ventilation comprises low tidal volume (6-8 ml/kg predicted body weight), control of respiratory plateau and driving pressures, moderate positive end- expiratory pressure (PEEPS cm H20), and minimal safe level of inspired oxygen fraction. Pharmacological prevention ofARDS has shown quite satisfactory experimental results and needs further clinicql investigations.

PREOXYGENATION: COULD SAFETY MEASURE BE MADE LESS DANGEROUS?.

While providing reserve time for dificult airway management, preoxygenation with pure oxygen increases the risk of pulmonary complications due to absorption atelectases. The authors explored when it could be appropriate to prevent atelectases by preoxygenation with decreased FiO2. ASA I-II elective gynecological surgery patients were randomized among five groups (n = 22 each) with preoxygenation using FiO2 100, 70, 60, 60% + PEEP 5 mbar and 50%. Even FiO2 70% led to decrease. in safe apnea time (i.e. time interval to Sp²O2 95%) by two, while FiO2 50% - by more than three times. Furthermore, in five similar additional groups of women with same techniques ofpreoxygenation (n = 10 each) it was shown that for FiO2 5 70% very fast pattern of SpO2 fall after the first change ofpulseoxymeter figure (100% by 99%) is typical: interval to SpO2 90% was less than 1 min, while for FiO2 100% it lasts for 200 s. Since critical problem is "Cannot intubate, cannot ventilate", the authors tried to focus on the difficultfacemask ventilation prognosis. In the group of 71 elective general surgery patients (31 males, 40 females, ASA I-III) original prognostic model based on seven simple bedside tests (removable dentures, beard, snoring, Mallampati class 2-4, age > 50 y.o., BM > 30 kg/m², sternomental distance < 12 cm) demonstrated the reliability of difficult facemask ventilation negative prognosis of 97,5%. The authors suggest that only in patients with reliable prognosis of easy facemask ventilation prevention ofpulmonary complications by preoxygenation with FiO2 50-60% could be safely recommended.