Male:female ratio was 3:4. Average age was 64 years (range: 41-79). Tumor stage was known in 44 patients. Sixty-eight percent of patients presented to surgery at T3N1 stage (n=30), 16% were at T2Nx stage (n=8) and 14% at T1Nx (n=6).
Pre-and intra-operative data
The majority of patients were considered ASA II grade (67%; n=31) and ASA III (n=11; 25%) while a minority were considered as ASA I (n=8%; n=3). POSSUM mean score was 20. First and third quartiles were 16 and 22, consecutively. Patients were grouped into three arbitrary categories of POSSUM ranges: 11-15, considered low risk (n=10; 22%), 16-21, considered intermediate risk (n=20; 45%), and 22-30, considered high risk (n=15; 33%).
ILOS, PO complications, and OLV
The ILOS represented the total stay of immediate PO admission and any later readmission (excluding High Dependency Unit, HDU). Mean ILOS was 8.4 days (range: 2-62 days). The mean length of OLV was 150 minutes (range: 90-320 minutes). Patients discharge from the ICU was usually within 48 hours post-operatively provided they were vitally stable with satisfactory analgesia. The care was continued on surgical wards and occasionally on HDU. ILOS correlated positively with OLV (Spearsman's R=0.49, P=0.001). The linear regression model, in this case yielded a P value of 0.015 (F-ratio=6.58). The mean total duration of surgery (TOT) was 442 minutes (range: 240-600 minutes). The ILOS did not correlate with the TOT. All early deaths (within the first 3 month post-operatively) had a relatively more prolonged OLV compared to patients who died after the 3rd month (P=0.032, Pearson's Chi Square statistic: 8.813). The ratio OLV: TOT (mean=0.353; range: 0.25-0.75) more strongly correlated with the ILOS than OLV itself (P<0.001; Pearson's R statistic: 0.513; intercept: 0.345). Anastomosis leak seems also to be affected by this ratio (P=0.015; t statistic: −2.555; df: 37).
4.4% of patients (n=2) died within the first month of surgery, 2.2% within the first 3 months, and 6.7% (n=3) died after the 3rd month and within the 12 months post-operatively. All these deaths occurred in patients operated at stage tumor stage T3Nx and represented a mortality of 20% (n=6) in this group (n=30) and 13.3% of all patients (n=45). Respiratory complications such as chest infections, loss of space, pleural effusions, and retained secretions were observed in 54% of patients (n=24) with 18% (n=8) defined as “acute respiratory failure”. As a whole, respiratory complications did not correlate with the total ILOS (R=0.024; P=0.88), the duration of surgery (P=0.98) or the length of OLV period (P=0.94).
PO atrial fibrillation (AF) was observed in 27% of patients (n=12). The incidence of sepsis reached 20% (n=9). Anastomosis leak occurred in 9% of patients (n=4). Serious myocardial ischemic events were observed in 7% of patients (n=3). Variable mild gastrointestinal and central nervous system (CNS) symptoms were observed in 22% of patients (n=10).
Pre- and intra-operative status
POSSUM value [Tables and ] correlated with the ILOS (Spearsman's R=0.39, P=0.05). Regression analysis shows a relatively strong relationship between the two variables (P=0.03; F-ratio=5.33). ASA grade significantly correlated to the ILOS (Spearsman's R=0.39, P=0.007), linear regression model yields a significant P value at 0.017 (F-ratio=6.2). Age, on the opposite did not correlate with the actual ILOS (Spearsman's R=0.25, P=0.095).
Quality of PO analgesia
Depending on how often they required additional interventions to achieve satisfactory pain control, patients were grouped into three categories. In category “a”, 60% of patients (n=26), the TEA was adequate without requiring more than one “top-up bolus” dose as a rescue intervention, “b”, 16% of patients (n=7), up to three top-ups boluses were needed for adequate analgesia and “c”, 24% (n=10), more than three top-ups resiting the epidural catheter or complete change of mode of analgesia were required. Thus, “a” was considered as excellent, “b” very good to good and “c” poor analgesia. Patients who received an excellent to good epidural analgesia had shorter ILOS (P=0.023) but no statistical link could be made between the quality of analgesia and the incidence of PO adverse respiratory events (P=0.52).
Readmission to the ICU
As many as 25% of patients (n=11) had to be readmitted on the ICU for mechanical ventilation. However, this event itself did not lead to a longer overall ILOS of these patients (Mean 14.2; SD=12.8) versus those who did not require re-ventilation (Mean=6.5; SD=12.02). Despite clinical significance, statistical significance could not be confirmed (P=0.073). Moreover, the association between respiratory complications and re-ventilation requirement is found to be non-significant (P=0.063).
PO AF, respiratory events and avIOF
Although, as common as in 29% of patients (n=14), AF did not significantly increase the ILOS (Mean=11 vs 7.2 days; SD=13.3 vs 12.2; P=0.3). Nevertheless, the occurrence of respiratory complications was strongly associated with that of AF (P=0.011). The average rate of avIOF significantly affected the occurrence of respiratory complications (P=0.036) without an increase of the requirement for re-ventilation (P=0.07). No significant association was confirmed between avIOF (P=0.289) nor the ILOS (P=0.84). While the avIOFc, could have a significant effect on the ILOS. Thus, patients who received an avIOFc <0.6 l/hour were more likely to spend less than eight days ILOS (P=0.023; Pearson's Chi Square statistic=13.0).