Pneumoperitoneum As the Presenting Sign of Pulmonary Barotrauma During Artificial Ventilation

Intensive Care Med (1986) 12:49-51 Intensive Care Medicine © Springer-Verlag1986

Pneumoperitoneum as the presenting sign of pulmonary barotrauma during artificial ventilation

B. Beilin, D. L. Shulman, A. T. Weiss and P. Mogle

Department of Anesthesia, Intensive Care Unit, and Department Radiology, Hasdassah University Hospital, Jerusalem, Israel Accepted: 17 June 1985

Abstract. Massive pneumoperitoneum developing im- another hospital. On admission he was unconscious mediately following initiation of artificial ventilation and cyanotic, with blood pressure 105/70, heart rate is an unusual sign of pulmonary barotrauma, and 120/min, and breathing frequency (f) 28/min. There must be distinguished from pneumoperitoneum fol- was marked jugular venous distention and expiratory lowing rupture of a hollow abdominal viscus. We pre- rhonchi were present over both lung fields. Ascites sent a case of massive pneumoperitoneum and scrotal was noted in the abdomen, and there was massive pneumatocele which we attributed to pulmonary edema in the legs extending up to the abdominal wall. barotrauma after excluding other causes. Awareness Arterial blood gas examination revealed severe of this entity will enable early diagnosis and avoid un- respiratory acidosis with pH 7.05, pO E 8.0 kPa, pCO2 necessary laparotomy. 14.1 kPa, HCO3 33 mmol/1. Chest X-ray showed pulmonary congestion and right-sided pleural effusion Key words: Pneumoperitoneum - Scrotal pneuma- superimposed on hyper-inflated lungs fields. tocele - Artificial ventilation - Pulmonary baro- Naso-tracheal intubation was performed without trauma difficulty and artificial ventilation (Bennett MA-1) with tidal volume (Vt) of 800 ml, and f of 16/min commenced. Peak inspiratory flow (PIF) was 25 l/ min and peak inspiratory pressure (PIP) 30-35 cm Extra-alveolar air is occasionally found as a complica- H20. The patient was treated with diuretics and anti- tion of pulmonary barotrauma during artificial venti- biotics and sedated. Blood gas values improved con- lation [4] or cardio-pulmonary resuscitation [1]. Sub- siderably, and heart rate decreased to 96/rain. cutaneous emphysema, pneumothorax, or pneumo- Over the subsequent 30min, the abdomen in- mediastinum are most commonly seen. Pneumoperi- creased in girth to a circumference of 129 cm, and was toneum (PP) is occasionally present, and may be the tympanitic with flank dullness. Concomitantly, the first clinical manifestation of extra-alveolar air. This scrotum became markedly distended. PII increased to presents the clinician with a diagnostic dilemma. We 45 - 50 cm H20. There were no other clinical signs of describe a case of massive pneumoperitoneum with extra-alveolar air and chest X-ray taken at this time scrotal pneumatocele which developed early after (Fig. 1) showed no change from admission. Approxi- starting artificial ventilation. mately 2 h later subcutaneous emphysema was noted on the chest wall. Lateral X-ray of the abdomen (Fig. Case report 2) showed extensive pneumoperitoneum. An abdominal tap confirmed that the swelling was due to air, and A 57-year-old man, weighing 90 kg, was seen in the the possibility of perforation of a hollow viscus was emergency room with respiratory failure and CO2 entertained. However, an upper gastro-intestinal narcosis. He was previously known to have chronic examination with gastrografin injected into the naso- obstructive pulmonary disease (COPD) and severe gastric tube showed a normal distal esophagus, right heart failure with hepatomegaly and anasarca. A stomach, and duodenum. A small bowel film taken at few days prior to admission a drain had been inserted 60 min showed good passage with no evidence of per- into the abdominal cavity for treatment of ascites at foration. 50 B. Beilin et al.: Pneumoperitoneum from pulmonary barotrauma

Discussion

Extra-alveolar air results from barotrauma to alveoli which rupture and leak air into the perivascular space [5]. This may occur at lower PIP in patients with COPD than in patients without previous lung disease [4]. The air then tracks back along perivascular sheaths to the hilum, and may continue to spread causing pneumothorax, pneumomediastinum, subcutaneous emphysema, or may gain access to the retro- peritoneal space via the hiatus [5]. From here, the air may dissect forward to the anterior abdominal wall and/or rupture into the peritoneal cavity. In our patient, the disruption of the peritoneum from the previous abdominal drainage may have facilitated access of the air into the peritoneal cavity. The scrotum may be distended from subcutaneous air or a sacrotal pneumatocele may develope from air which enters directly from the peritoneal cavity [3]. Fig. 1. Chest X-ray, supine, following intubation and onset of dis- The appearance of PP immediately after initiation tension of the abdomen of artificial ventilation and as the first sign of pulmonary barotrauma is exceedingly rare. Hillman [4] reported that only 2 of 28 cases of PP occurred immediately after initiation of controlled ventilation, and PP occurred in most of this patients more than 24 h later. He pointed out that high levels of PEEP and Drains were inserted into the peritoneal and PIP of more than 40 cm H20 were generally responsi- scrotal cavities and abdominal girth decreased mark- ble for development of PP. Pneumothorax was asso- edly. In order to achieve low airway pressure, high ciated with PP in most of his patients, although frequency ventilation was used [2]. The ventilator was pneumomediastinum and subcutaneous emphysema set to trigger at maximum sensitivity, PIF of 1001/s were also frequent accompaniments. Thus the patient and Vt of 150ml, and with these settings f was described here was unusual in that PP developed im- 100/min, and PIP 20-30 cm H20. During the next mediately after artificial ventilation commenced 24 h he improved considerably, returned to full con- without the use of high PIP or PEEP, and that, sciousness, and the drains were removed. However, initially, there was no other sign of extra-alveolar air. on the third hospital day cardiac arrest occurred The entity of PP caused by pulmonary baro- suddenly and resuscitation was unsuccessful. trauma is important since it may be confused with PP

Fig. 2. Lateral X-ray of the abdomen showing extensive pneumoperitoneum. The arrows indicate the anterior abdominal wall B. Beilin et al.: Pneumoperitoneum from pulmonary barotrauma 51

from rupture of a hollow intra-abdominal viscus. 3. Gordon HI, Walkup JL (1970) Scrotal pneumatocele as an Laparotomies have been performed on these patients, unusual sign of pneumoperitoneum: report of a case and review sometimes with disastrous results [4]. This unusual of the literature. J Urol 104:441 4. Hillman KM (1982) Pneumoperitoneum - a review. Crit Care clinical finding should be recognized and appropriate- Med 10:476 ly treated by physicians who care for artificially ven- 5. Maunder R J, Peirson D J, Hudson LD (1984) Subcutaneous and tilated patients. mediastinal emphysema pathophysiology, diagnosis, and management. Arch Intern Med 144:1447

References Dr. B. Berlin 1. Atcheson G, Peterson GV, Fred HL (1975) Effects of cardiac re- Department of Anesthesia suscitation: report of two cases. Chest 67:615 Hadassah University Hospital 2. Flatau E, Lewinsohn G, Konichezky S, Lev A, Barzilay E (1982) Mount Scopus Mechanical ventilation in fiberoptic-bronchoscopy: comparison P.O. Box 24035 between high frequency positive pressure ventilation and normal Jerusalem frequency positive pressure ventilation. Crit Care Med 10:733 Israel 91240

Book review

Critical Care in Internal Medicine. D. R. McCaffree (ed). Basel: the book is the one entitled Metabolism with covers such topics as Karger 1985. 15 figs., 54 tables, US $ 57.00 disorders of potassium, calcium, magnesium and phosphate, hypo- natraemia, acid base problems and thryoid and adrenal disorders. These chapters give a lucid summary of the physiology involved, an This book is one of a series based on experience gained at the Uni- understanding of which is, of course, the key to rational manage- versity of Oklahoma in presenting a postgraduate course in Critical ment of these disorders, and cover common presentations and their Care Medicine. It aims to be a "useful and frequently utilized pre- therapy. The three chapters devoted to infection in the setting of sentation of the problems encountered in critically ill patients by in- the Intensive Therapy Unit are also well written and adequately ternists, family practitioners and surgeons". Respiratory failure cover the relevant topics, including the important practical aspect and cardiac emergencies are excluded from the topics discussed; of prevention. The section devoted to disorders of the cardiovascu- these are to be the subject to future volumes. The book is well pre- lar system, perhaps again in anticipation of the next volume, does sented, easy to read and includes 15 figures and 54 tables. Each not cover cardiogenic shock, acute myocardial infarction, or the chapter has a comprehensive and up-to-date list of references, management and prevention of arrhythmias. The chapter on the which also refer the reader to reviews of topics that cannot be ade- pitfalls in the interpretation of haemodynamic data is excellent, quately covered within the text. The opening chapters of the book though the number of abbreviations used is at first a little daunting. are headed "Medicine and Humanity". The first deals with a physi- Other cardiovascular topics covered include hypertensive emergen- cian's personal experience of critical illness and is entitled "Life at cies, pulmonary thrombo-embolism, intravenous fluids for resusci- the Other End of the Endotracheal Tube". The second chapter is an tation (the colloid vs. crystalloid debate), drugs in the hypo- experienced physician's view of "Mechanical Ventilation and Hu- perfusion syndrome and blood and blood substitutes. This last man Ethics". Both these superb chapters present a timely reminder chapter is an excellent practical guide to the indications and contra- that no intensive care unit should be run without a consideration of indications for blood and blood component therapy, giving a well the humane and ethical issues involved and the book is worth read- presented discussion of the types of components available, their ing for these alone. Other sections include chapters covering the uses, the changes that take place in stored blood and their clinical central nervous system, the respiratory system, the cardiovascular significance, the current state of the research on blood substitutes system, the renal and digestive systems and excellent sections on and recognition and treatment of complications resulting from metabolism, infections and pharmacology and poisoning. The sec- transfusion. The only topic covered in the section on disorders of tion on the respiratory system is the weakest part of the book the central nervous system is the management of status epilepticus. (perhaps in anticipation of the next volume) being rather sparse Again a description of the clinical features, causes and management with the very details the readership would want to know. "Mechan- is given, and the pharmacology of the common used drugs is dis- isms of Acute Lung Injury" gives a brief state of the art summary cussed. A chapter dealing with the management of the acute head of the pathophysiology of ARDS with no comment on either pre- injury and the all too common problem of hypoxic cerebral damage vention or therapy. The chapter on mechanical ventilation gives a in the patient resuscitated from a cardiac arrest would have been short history of the subject, a description of the types of ventilator very valuable. This book is an excellent, practical guide to the available (volume or pressure cycled) advice on setting up a ventila- everyday management of critical illness, based on an understanding tor, on monitoring of the ventilated patient and a cursory descrip- and appreciation of the fundamental pathophysiology. Although it tion of the uses and functions of PEEP. The rather woolly section would be expensive for an individual there is more than enough on complications would benefit from a summary in table form. The sound advice to warrant a departmental purchase. If the first two significance of changes in the parameters being monitored is not chapters were compulsory reading for everyone involved in inten- well discussed and the crucial subject of weaning is not covered at sive care, then the investment in the book could be repaid hand- all. The question of maintaining patient comfort and sedation while somely. I look forward to the next volume. on the ventilator is not addressed. The most worthwhile section of R. J. Eltringham (Gloucester)