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Arslan et al. Mini-invasive Surg 2018;2:4 I http://dx.doi.org/10.20517/2574-1225.2017.31 Page 5 of 10

and the gas should be evacuated immediately. Left lateral decubitus position must be applied to prevent the
gas from entering pulmonary artery. A central venous catheter should be placed for aspirating the gas and
100% O hyperventilation and proper cardiopulmonary resuscitation should be applied.
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Pulmonary complications
Possible pulmonary complications related to laparoscopy are hypoxemia, hypercarbia, barotrauma,
pneumomediastinum, pneumothorax, atelectasis and pulmonary edema [7,12,32] . As it is previously
mentioned increased IAP in pneumoperitoneum causes an increase in peak airway pressures, a decrease
in lung volumes and a decrease in pulmonary compliance. Trendelenburg position increases these
effects further. These changes cause a ventilation/perfusion (V/P) mismatch and atelectasis. Eventually
hypoxemia and hypercarbia may occur due to ineffective gas exchange. Hypercarbia and respiratory
acidosis may be avoided by hyperventilation, which means 15%-25% increase in minute ventilation should
be maintained [12,33] . But during hyperventilation it is suggested to increase the respiratory rate and not the
tidal volume; especially in patients with COPD, in patients with history of spontaneous pneumothorax
or bullous emphysema; because high peak airway pressures and reduced pulmonary compliance may
increase the risk of barotrauma and a spontaneous pneumothorax [33,34] . Increase in minute ventilation may
be provided by using both pressure-controlled ventilation and volume-controlled ventilation. Pressure-
controlled ventilation was reported to decrease peak airway pressure and increase dynamic compliance
[35]
[36]
and found superior to volume controlled ventilation by Assad et al. . But Balick-Weber et al. and
[37]
Choi et al. reported that these two ventilation techniques are not superior to each other regarding

respiratory mechanics and hemodynamics. Endo-tracheal intubation with either volume or pressure
controlled ventilation is the recommended technique, especially for longer operations, because it provides
a better control over CO and prevents gastric regurgitation. But for shorter operations which can be
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performed at lower IAP levels, using conventional laryngeal mask airway (LMA) or a ProSeal® LMA (ProSeal
LMA, San Diego, CA, USA) was found to be safe and effective in some laparoscopic gynecological operations
and laparoscopic cholecystectomies; therefore it may be valid for laparoscopic urological operations without
Trendelenburg position lasting < 2 h and performed at lower IAP levels [38-40] . Increased IAP during CO
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insufflation and Trendelenburg position may cause the distance between carina and endotracheal tube
tip to become shorter leading to inadvertent endobronchial intubation and hypoxemia (due to ineffective
[41]
ventilation) . Endotracheal tube’s position should be checked regularly through the surgery and it
should be checked if both sides are equally ventilated in order to avoid this complication. Patients without
pulmonary disease usually tolerate side effects of pneumoperitoneum and Trendelenburg position well with
[23]
proper anesthetic management and postoperative care . However, it may be more severe in patients with
pulmonary dysfunction; so these patients must be carefully assessed preoperatively with pulmonary function
tests and arterial blood gas analysis should be performed at preoperative evaluation and regularly during
surgery through an artery cannula. If hypoxemia and hypercarbia persist even after proper interventions,
pneumoperitoneum should be ceased and a slow re-insufflation should be applied or convertion to open
[12]
surgery should be considered if necessary .
Subcutaneous emphysema
Subcutaneous emphysema is the presence of gas in subcutaneous tissue passing through a disruption in
[42]
peritoneum or through an inadvertent placed trocar. In a study conducted by McAllister et al. showed,
up to 56 % of the patients after laparoscopic surgery had subcutaneous emphysema. However, this
situation is mostly benign and is not serious. The clinical detection rate is between 0.3%-3% in laparoscopic
[7]
surgeries . Subcutaneous emphysema may extend to mediastinum and pleura causing pneumothorax and
pneumomediastinum, or vice versa it may be the sign of an extended pneumothorax or pneumomediastinum
[7]
to subcutaneous tissue . Most of the cases with subcutaneous emphysema is clinically insignificant,
however its relevance with pneumothorax and pneumomediastinum must be remembered. Also, if the
neck is involved, obstruction of upper airways may be present. Risk factor for subcutaneous emphysema are
[43]
multiple trocars, end tidal CO levels higher than 50 mmHg, prolonged operative time and old patients .
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