A total of 341 patients undergoing, either single or double, lung transplantation during the study period (between July 2007 and August 2017): 146 (43%) female and 195 (57%) male, with a mean (SD) age of 49.4 (14) years. Sequential T was the preferred surgical access performed in 148 (43%), patients followed by S in 98 (29%) and C in 95 (28%) patients (Table 1).
Clinical outcomes related to surgical access after lung transplantation
Postoperative pain. As first option in ICU pain management, systemic opioid (morphine) was the most popular analgesic regime in 249 (73%) patients, and epidural analgesia without morphine was used in 92 (27%) patients.
In 76 (31%) out of 249 patients in whom systemic opioids were not sufficient, were converted to epidural analgesia. Therefore, in 173 (51%) out of 341 patients systemic opioids was the sole analgesic regimen.
Analysing the impact of surgical technique on pain intensity, we found that T was associated with higher pain scores than S (OR: 1.66, 95%CI: 1.01; 2.74, p-value: 0.045) and there seemed to be no differences between C and S incision. Thoracotomy was associated with more acute pain than rest of two other incisions. Two independent protective factors for high pain scores (considerable pain and very severe pain) were found: age (OR 0.98, 95%CI: 0.97; 1,00, p-value: 0.025), and single lung transplantation (OR 0.49, 95%CI: 0.28; 0.85 p-value: 0.010).
In the epidural analgesia group (n=92), T was also the most frequent access: 54 patients (59%); followed by C in 34 (37%) and S in 4 (4%). Indications for lung transplantation revealed no differences in frequency of epidural analgesia: 29 COPD patients (21%), 23 cystic fibrosis (31.5%), 18 pulmonary fibrosis (28.1%), 17 Interstitial lung disease (37.7%) and 5 in pulmonary hypertension (23.8%). Median [IQR] of number of pain score measurements per patient treated with epidural block was 50.5 [31; 92].
Blood loss. Postoperative blood loss data in the first 24 h was available for 327 patients. Amongst all groups the median of blood loss was 800 [IQR: 500; 1238] mL/24 h. T group had statistically significant lower blood loss during the first 24 h than the other 2 surgical incisions (p-value: <0.001) (Table 2). Single lung transplantation patients had a median blood loss of 480 [IQR: 291; 928] mL while double lung patients had a bleeding of 875 [IQR: 600; 1350] mL/24 h, p-value<0.001.
Mechanical ventilation. Duration of mechanical ventilation was available for 327 patients (Table 2). The duration of mechanical ventilation for the Thoracotomy group was significantly lower (median [IQR] of 19 [11; 37] hours) than the C group 34 [IQR 16; 57.5] hours (p-value: 0.012)) and in the S group 27 [IQR 15; 50.5] hours (p-value: 0.012). Figure 1 shows the impact of the type of surgical incision on the duration of mechanical ventilation.
In the linear regression analysis, the analgesic technique (only systemic opioid or systemic opioid and epidural analgesia) was not associated with differences on duration of mechanical ventilation. In order to further analyze this relationship a Cox model was performed. In the univariate analysis T (HR: 1.41, 95%CI: 1.08;1.83), single lung transplantation (HR 1,43, 95%CI: 1.09;1.86) and absence of cardiopulmonary by-pass (HR 1.32 , 95%CI: 1.06; 1.65) were associated with earlier extubation. In the multivariate model similar relations were gathered with T showing a HR: 1,40 (95%CI: 1.08; 1.8) for extubation, Single lung transplantation HR:1.58 (95%CI: 1.18; 2.1) for extubation and absence of cardiopulmonary by-pass HR: 1.29 (95%CI: 0.99; 1.7) for extubation.
Length of ICU stay. Intensive Care Unit length of stay was not documented in 21 patients. The duration for different groups was as follows: T group spent a median [IQR] of 72 [48; 120] hours, C group 72 [48; 180] hours and 96 [72; 204] in S group. Survival curves showed that T group were discharged earlier from ICU (p value: <0.001) than S group and C group (Figure 2). Analgesic technique did not influence in the length of stay in ICU in univariate Cox model (HR 1.16 [0.91;1.48] p-value: 0.223). In the multivariate analysis single lung transplantation was associated with a shorter admission in ICU (HR 1.337 [1.014;1.8] p-value: 0.039).
Safety
During the study period no epidural hematoma or abscess were diagnosed. There were 2 recorded complications of epidural analgesia: One dural tap, which did not require further treatment as there was very mild headache. One epidural was placed too low not providing optimal analgesia and it had to be repositioned within the first 24 hours.