[Serious mechanical complications associated with pulmonary artery catheters in cardiovascular and thoracic surgery]

OBJECTIVE

Although the use of pulmonary artery catheters (PACs) in managing critical patients is a subject of debate, they continue to be inserted in many cases and possible complications should be taken into account. Our objective was to review the serious or potentially serious complications associated with PACs in our hospital in the past 15 years.

PATIENTS AND METHODS

This was a retrospective study of seious mechanical complications of PAC use in patients who underwent vascular, cardiac, and thoracic surgery.

RESULTS

The study included the records 7540 patients; 9 cases of serious complications were detected. These complications included 5 cases of pulmonary artery rupture (3 of which resulted in death), 1 perforated internal mammary vein, 1 knotted catheter, 1 bent one, and 1 case of a PAC becoming trapped in the surgical suture.

CONCLUSIONS

The 0.12% incidence of complications is lower than rates found in the literature. Although these complications are rare, it is necessary to take precautions against their unexcepted appearance by carefully selecting the patients in whom PACs are placed and by paying special attention to the characteristic clinical and radiological signs of complications.

[Behaviour of near-infrared cerebral oximetry readings during percutaneous carotid angioplasty]

BACKGROUND

Transluminal percutaneous carotid angioplasty and stenting (CAS) carries a risk of cerebral ischemia, hemorrhage, or edema due to relative hyperemia and hemodynamic instability during and after the procedure. Noninvasive monitoring of near-infrared regional cerebral oxygen saturation (SrO2) offers an indirect way to estimate cerebral blood flow.

OBJECTIVE

To evaluate the behaviour of SrO2 during CAS and the usefulness of this variable for continuous monitoring of cerebral blood flow variation and neurological status.

MATERIAL AND METHODS

Prospective study of 25 patients scheduled for unilateral CAS under monitored anesthesia care. SrO, and other hemodynamic and clinical data were recorded. A change in SrO2 (deltaSrO2) of 15% or more in comparison with the baseline value and lasting more than 30 seconds was considered clinically significant. Neurological complications in the first 24 hours were also registered.

RESULTS

Baseline SrO, ranged from 51% to 75%. With administration of papaverine SrO2 values increased by a mean (SD) of 5.6% (6%) (P<.05 vs baseline). They decreased during angioplasty, -2.5% (5.7%) (P<.05 vs baseline), increased after 5 minutes, and fell again at 30 minutes to a level 3% (6.54%) above baseline. Two patients showed signs of elevated intracranial pressure after the procedures and also had ASrO2 readings exceeding 15%; measures to lower arterial hypertension reduced SrO2 in these patients.

CONCLUSION

High interindividual variability of absolute SrO2 values has been confirmed. SrO, fluctuates with maneuvers that change cerebral blood flow in the same way. Changes can precede the onset of other clinical signs.

Dobutamine restores intestinal mucosal blood flow in a porcine model of intra-abdominal hyperpressure

OBJECTIVE

To assess the effects of dopamine and dobutamine administration on the systemic and mesenteric (macro- and microvascular) circulatory disturbances induced by intra-abdominal hyperpressure.

DESIGN

Prospective, randomized study.

SETTING

Animal research laboratory in a university hospital.

SUBJECTS

Twenty-five pigs of either gender, weighing 30-35 kg.

INTERVENTIONS

Animals were anesthetized, and their lungs were mechanically ventilated. Pulmonary artery flotation and carotid artery catheters were inserted for hemodynamic monitoring and blood sampling. A perivascular flow probe was placed around the superior mesenteric artery, and a laser Doppler probe was positioned in the lumen of the ileum to measure arterial and intestinal mucosal blood flows, respectively. CO2 was insufflated into the peritoneal cavity to reach an intra-abdominal pressure of 15 mm Hg, and 60 mins later, animals received dopamine (5 microg/kg/min; n = 10), dobutamine (5 microg/kg/min; n = 10), or saline (n = 5) for 30 mins.

MEASUREMENTS AND MAIN RESULTS

Peritoneal CO2 insufflation induced significant increases in heart rate, arterial pressure, and systemic vascular resistance with concomitant decreases in cardiac output and superior mesenteric arterial and intestinal mucosal blood flows. Although dobutamine infusion reversed the decrease in cardiac output, it failed to restore superior mesenteric artery blood flow; however, intestinal mucosal blood flow returned to baseline levels. Dopamine also attenuated the decrease in cardiac output, but it had no beneficial effect on splanchnic hemodynamic variables.

CONCLUSIONS

Low-dose infusion of dobutamine, but not dopamine, corrects the intestinal mucosal perfusion impairment induced by moderate increases in intra-abdominal pressure.

Helium and carbon dioxide pneumoperitoneum in patients with pheochromocytoma undergoing laparoscopic adrenalectomy

Insufflation with helium is used to prevent respiratory acidosis, hypercapnia, and cardiovascular instability associated with carbon dioxide (CO2) pneumoperitoneum. The aim of this prospective study was to compare CO2 with helium pneumoperitoneum with special reference to respiratory and hemodynamic changes at different times during the operation. Altogether 22 pheochromocytoma patients undergoing laparoscopic adrenalectomy (LpA) were included using CO2 in 11 patients (CO2LpA) and helium in 11 patients (HeLpA). The insufflation pressure was 12 mmHg. The two groups were comparable with regard to demographic data and preoperative management. CO2 and helium insufflation were associated with similar catecholamine increase. The most striking significant increase compared with the baseline was observed during tumor isolation: The mean plasma epinephrine (EPI) and norepinephrine (NE) levels increased 32.86-fold and 25.92-fold, respectively, in the CO2LpA patients and 27.43-fold and 18.46-fold, respectively, in the HeLpA patients. HeLpA did not result in significant hypercarbia or acidosis at any measured intraoperative point; this was without any alteration in minute ventilation to maintain these normal PaCO2, excess base (EB), and pH values. Significant increases of mean arterial pressure, pulmonary arterial pressure, pulmonary vascular resistance index, PaCO2, EB, and acidosis were seen in the CO2LpA patients at the time of tumor isolation and tumor removal compared with those in HeLpA patients. No patient required conversion to open surgery. There were no significant differences between CO2LpA and HeLpA regarding mean operative time (117.50 +/- 93.68 vs. 106.87 +/- 16.60 minutes), mean blood loss (168.54 +/- 78.63 vs. 142.02 +/- 109.26 ml), hospital stay (4 days), the need for analgesics, or mean time required to return to normal activity (12 days). There was one wound infection in the HeLpA group and one wound hematoma and one case of atelectasis in the CO2LpA group. Helium may be the agent of choice for abdominal insufflation in patients undergoing LpA for pheochromocytoma, eliminating the adverse hemodynamic and respiratory changes associated with CO2 insufflation.

Effects of carbon dioxide vs helium pneumoperitoneum on hepatic blood flow

BACKGROUND

Elevated intraabdominal pressure due to gas insufflation for laparoscopic surgery may result in regional blood flow changes. Impairments of hepatic, splanchnic, and renal blood flow during peritoneal insufflation have been reported. Therefore we set out to investigate the effects of peritoneal insufflation with helium (He) and carbon dioxide (CO2) on hepatic blood flow in a porcine model.

METHODS

Twelve pigs were anesthetized and mechanically ventilated with a fixed tidal volume after the stabilization period. Peritoneal cavity was insufflated with CO2 (n = 6) or He (n = 6) to a maximum intraabdominal pressure of 15 mmHg. Hemodynamic parameters, gas exchange, and oxygen content were studied at baseline, 90 mm and 150 min after pneumoperitoneum, and 30 min after desufflation. Determination of hepatic blood flow with indocyanine green was made at all measured points by a one-compartment method using hepatic vein catheterization.

RESULTS

A similar decrease in cardiac output was observed during insufflation with both gases. Hepatic vein oxygen content decreased with respect to the baseline during He pneumoperitoneum (p < 0.05), but it did not change during CO2 insufflation. Hepatic blood flow was significantly reduced in both the He and CO2 pneumoperitoneums at 90 min following insufflation (63% and 24% decrease with respect to the baseline; p < 0.001 and p < 0.05, respectively) being this decrease marker in the He group (p = 0.02).

CONCLUSIONS

These findings suggest that helium intraperitoneal insufflation results in a greater impairment on hepatic blood flow than CO2 insufflation.

[Cardiopulmonary resuscitation in hospitalized patients in conventional units. Prospective study of 356 consecutive cases. Commission for Care of Cardiorespiratory Arrest]

BACKGROUND

Information regarding to the system functioning and to the outcome of patients in whom cardiopulmonary resuscitation (CPR) was performed during their in hospital period in non intensive care units are essentially lacking in Spain. The objectives of the present work were: 1) to define clinical and demographic characteristics of the patients who develop cardiopulmonary arrest in general hospitalization wards; 2) to analyze immediate and late (at discharge) survival rates as well as the frequency of severe sequelae in final survivors; 3) to identify prognostic factors in relationship to survival, and 4) to detect possible internal deficiencies in the organized system of CPR.

PATIENTS AND METHODS

All patients who develop cardiac and pulmonary arrest through their hospitalization in general wards during a three year period, were prospectively included. Clinical and demographic data from all the patients as well as data related to the internal functioning of the system were recorded.

RESULTS

From 356 included cases, 196 (55%) were initially recovered and 128 (36%) were discharged from the hospital. Among the latter group, 12.5% remained with severely disabling neurologic damage. Age under 80 years, resuscitation maneuvers for less than 20 minutes and respiratory arrest as the ultimate event leading to cardiopulmonary arrest were associated with better prognosis. The internal deficiencies most commonly recorded in the system were false calling to the emergency team, the wrong identification of the location in the hospitalization unit and several abnormalities in the content of CPR sets.

CONCLUSIONS

With the currently available organized system directed towards CPR for patients admitted in general hospitalization wards, our rates of success are good and similar to those achieved in some intensive care units. Thus, a similar policy may be encouraged in large hospitals. Since most of the detected deficiencies in internal functioning are easy to rectify, a close monitoring is warranted in order to optimize the results.