Anaesthesia, 1992, Volume 46, pages 128-1 30 CASE R E P O R T
Fatal pulmonary embolism following spinal anaesthesia for Caesarean section
S. P. McHALE, M. D. V. TILAK
AND
P. N. ROBINSON
Summary Pulmonary embolism remains one of the commonest causes of maternal death. Regional blockade is reported to decrease the incidence of postoperative thrombo-embolic disease. We describe a case in which a fatal pulmonary embolism followed an emergency Caesarean section for which the patient was given a spinal anaesthetic. We believe it to be thejirst time this has been reported.
Key words Anaesthesia; obstetric. Anaesthetic technique, regional; spinal. Complications; pulmonary embolism.
The report on Confidential enquiries into maternal deaths in the United Kingdom 1985-87, shows that pulmonary embolism and hypertensive disorders of pregnancy remain the most common causes of maternal mortality [I]. Of the 13 postpartum deaths from pulmonary embolism, seven followed Caesarean section, suggesting that the risk after operative delivery is markedly increased compared with vaginal delivery.
Case history An unmarried 29-year-old primiparous woman presented in spontaneous labour at 41 weeks' gestation. Her antenatal course had been uneventful and did not include any periods of immobilisation. She weighed 97.4 kg, smoked 10 cigarettes a day and had been normotensive throughout her pregnancy. Labour initially progressed well, during which she required for analgesia one intramuscular injection of pethidine 100 mg and Entonox. After 9 h her labour failed to progress because of cephalopelvic disproportion and an emergency Caesarean section became necessary. There was no fetal distress. The pre-operative haemoglobin level was 12 g.dl-' and baseline readings of heart rate 100 beats.min-', blood pressure 130/85 mmHg and an oxygen saturation of 96%
when breathing air were obtained. After premedication with 30 ml of sodium citrate the patient's circulation was preloaded with 1500 ml compound sodium lactate solution. She was turned onto her right side and a 26 g spinal needle was inserted at the L2-3interspace. Clear cerebrospinal fluid was obtained and 2.5 ml of hyperbaric 0.5% bupivacaine was injected into the subarachnoid space. A bolus dose of 9 mg of ephedrine was given intravenously as prophylaxis against hypotension. Twelve minutes later the patient was delivered of a live female infant weighing 4.08 kg, with Apgar scores of 9 at 1 min and 10 at 5 min. The operation was complete 53 min after the spinal injection. There were no episodes of hypotension and the blood loss was estimated to be 400 ml. The patient recovered well, did not develop a headache and was sitting out of bed 20 h after the operation. She required three intramuscular injections of papaveretum 20 mg for analgesia in the first 24 h and nothing after that. On the second postoperative day her temperature was 37.9" C, but this settled spontaneously. It was noted that her calves were not tender. All observations remained normal, but owing to social circumstances she was not discharged until the eighth postoperative day. The following day she was found dead at home. A postmortem revealed thromboses in the deep veins of the left leg and massive bilateral pulmonary emboli totally
S.P. McHale, MB, BS, BSc, FCAnaes, Registrar, M.D.V. Tilak, MB, BS, MRCP, FFARCSI, Senior House Officer, P.N. Robinson, MB, ChB, FFARCS, Consultant, Department of Anaesthetics, Edgware General Hospital, Edgware, Middlesex HA8 OAD. Correspondence should be addressed to Dr P.N. Robinson please. Accepted 23 June 199I . 0003-2409/92/020128 + 03 %03.00/0
@ 1992 The Association of Anaesthetists of Gt Britain and Ireland
128
Fatal pulmonary embolism following spinal anaethesia for Caesarean section Table 1. Postpartum maternal deaths from pulmonary embolism, England and Wales 1970-87, compared with United Kingdom 1985-87. Adapted from the Report on conJidential enquiries into maternal deaths in the United Kingdom 1985-87, London, 1991 HMSO.
England and Wales
United Kingdom
1970-72 1973-75 1976-78 1979-81 1982-84 1985-87 1985-87
Deaths after vaginal delivery
Deaths after Caesarean section
22 13 20 4 4 5 6
15
6 9 7 12 3 7
Total 37 19 29 II 16 8 13
occluding both main trunks of the pulmonary artery, with extension into all the peripheral vessels on the right side. There were no signs of thrombosis elsewhere and all other organs were normal. The cause of death was given by the coroner as massive bilateral pulmonary emboli due to deep vein thrombosis as a result of Caesarean section.
Discussion Pregnancy is known to be a hypercoagulable state, with an increase in the clotting factors 1, 2, 7, 8, 9, 10 and 12 [2]. There is also a decrease in the level of antithrombin 111 [3] and of plasma fibrinolytic activity [4]. Although the hyperdynamic circulation of pregnancy means that the overall circulation time is reduced, venous return from the lower limbs is decreased as the pregnant uterus obstructs the inferior vena cava. Thus the risk of thrombo-embolic disease is increased sixfold compared with the nonpregnant state, and is further increased by previous thrombo-embolism, obesity, lupus anticoagulant, immobilisation and operative delivery [ 11. Over the last decade clinical studies have suggested that anaesthesia may influence the development of postoperative deep venous thrombosis. Compared with general anaesthesia, subarachnoid block is associated with a significant decrease in the frequency of deep venous thrombosis (DVT) and pulmonary embolism following hip surgery [5-81. There is similar evidence for extradural blockade and knee surgery [9]. This may be due to an increase in blood flow in the lower limbs [lo] consequent upon vasodilatation, a decrease in platelet aggregation [I 11, enhanced fibrinolysis [I21 and a decrease in blood viscosity [13]. The latter effect is a combination of the preload, the increased deformability of red cells and the vasodilation associated with subarachnoid blocks. The reports on confidential enquiries into maternal death show that the number of postpartum deaths from pulmonary embolism has decreased since the 1970-72 triennium (Table I). Since this time there has undoubtedly been an increase in the use of regional anaesthesia but no study has yet shown that either subarachnoid or extradural blockade is associated with a decrease in thrombo-embolic phenomena in obstetric practice. Part of the problem lies in the diagnosis of DVT which is notoriously difficult from clinical signs alone. Furthermore, as less than 10% of all pulmonary emboli are fatal [14], the report on maternal mortality will show only a small percentage of the total
129
number of pulmonary emboli occurring in the pregnant population. The methods commonly used for prophylaxis against DVT include low dose subcutaneous heparin, intermittent pneumatic compression of the calves, elasticated stockings, low dose aspirin and ankle supports. Only the first of these is of proven benefit in abdominal surgery [15]. In the case reported here the patient’s ankles were supported away from the operating table. Theoretically, subarachnoid anaesthesia may be of benefit as an additional prophylaxis against thromboembolism when used with subcutaneous heparin. Early mobility is desirable, and perhaps a smaller volume of local anaesthetic solution should be used, and thus give a less dense motor block. If a smaller volume is injected then it may be necessary to use a combination epidural/spinal technique so that an inadequate block could be improved upon. However, if this was necessary a dense motor block would probably be produced. An advantage of using a combined spinal and epidural technique would be in the provision of postoperative analgesia. In a recent study, it was shown that in a group of patients who received a continuous infusion of low dose bupivacaine for the 3 days following knee replacement, there was a decrease in the incidence of DVT [9]. These patients also wore elasticated stockings. Alternatively, the epidural injection of an opioid could be used for postoperative analgesia. Once analgesia is adequate, mobilisation should be actively encouraged. The routine continuation of intravenous infusions may not be necessary in the patient who has had an uncomplicated Caesarean section with a regional anaesthetic. She could be given adequate oral fluids and, relieved of the infusion and drip stand, be more able to mobilise. All pregnant women are at risk of developing a DVT and those that have an operation have an increased risk. Should we be taking prophylactic measures in all women undergoing Caesarean section? Should low dose heparin with elasticated stockings become routine practice for such women? In the case reported, the patient possessed three risk factors for the development of DVT: she was overweight, pregnant and underwent an operation. Although it is not supported by any studies, perhaps people in risk groups should be offered a regional anaesthetic with subcutaneous heparin, postoperative epidural analgesia and early oral fluids. However, as with this case and in the majority of postnatal women who die following pulmonary embolism, the in-hospital postdelivery course was unremarkable and contained no significant periods of immobilisation.
References [I] Report on ConJdential Enquiries into Maternal Deaths in lhe United Kingdom 1985-87. London: HMSO, 1991. [2] BONNAR J, MCNICOLGP, DOUGLASAS. The blood coagulation and fibrinolytic systems in the newborn and the mother at birth. Journal of Obstetrics and Gynaecology of the British Commonweath 1971; 78: 355-60. [3] ZUCKER ML, GOMPERTS ED, MARCUSRG. Prophylactic and therapeutic use of anticoagulants in inherited antithrombin I11 deficiency. South African Medical Journal 1976; 5 0 1743-8. [4] BONNARJ, MCNICOL GP, DOUGLAS AS. Fibrinolytic enzyme system and pregnancy. British Medical Journal 1969; 3: 387-9. [5] THORBURN J, LOUDEN JR, VALLANCER. Spinal and general anaesthesia in total hip replacement: frequency of deep vein thrombosis. British Journal of Anaesthesiu 1980; 52: 1 I 17-2 I .
I30
S.P. McHale. M.D.V. Tilak and P . N . Robinson
[6] DAVIS FM, QUINCEM, LAURENSON VG. Deep vein thrombosis and anaesthetic technique in emergency hip surgery. British Medical Journal 1980; 281: 1528-9. HY, GRAY1, SMITHG. Effects of [7] MCKENZIE PJ, WISHART anaesthetic technique on deep vein thrombosis. A comparison of subarachnoid and general anaesthesia. British Journal of Anaesthesia 1985; 57: 853-7. (81 MODIGJ. Influence of regional anesthesia, local anesthetics, and sympathicomimetics on the pathophysiology of deep vein thrombosis. Acta Chirurgica Scandinavica 1989; 5 5 0 I 19-27. LS, NIELSEN PT, LEFFERSA. 191 J0RCENSEN LN, RASMUSSEN ALBRECHT-BESTE E. Antithrombotic efficacy of continuous extradural analgesia after knee replacement. British Journal of Anaesrhesia I99 I ; 66: 8- 12. [lo] COUSINS MJ, WRIGHT CJ. Graft, muscle, skin blood flow after epidural block in vascular surgical procedures. Surgery, Gynecology and Obstetrics 1971; 133: 59-64.
[ I I] BORC T, MODIGJ. Potential antithrombotic effects of local anaesthetics due to their inhibition of platelet aggregation. Acta Anaesthesiologica Scandinavica 1985; 2 9 73942. SG, FORSTER SJ, COOPER GM, HUGHES [I21 SIMPSON PJ, RADFORD GO. The fibrinolytic effects of anaesthesia. Anaesthesiu 1982; 37: 3-8. [I31 DRUMMOND AR, DRUMMOND MM, MCKENZIEPJ, LOWE GDO, SMITHG, FORBESCD, WISHARTHY. The effects of general and spinal anaesthesia on red cell deformability and blood viscosity in patients undergoing surgery for fractured P. eds Haemorrheology neck of femur. In STOLZJF, DROUIN and diseases. Paris: Doin Editeurs, 1980: 44-50. [I41 MOSER KM. Pulmonary embolism. American Review o / Respiratory Disease 1977; 115: 829-52. [IS] International Multicentre Trial; Prevention of fatal postoperative pulmonary embolism by low doses of heparin. Lancet 1977; ii: 45-51.
Fatal pulmonary embolism following spinal anaesthesia for Caesarean section
S. P. McHALE, M. D. V. TILAK
AND
P. N. ROBINSON
Summary Pulmonary embolism remains one of the commonest causes of maternal death. Regional blockade is reported to decrease the incidence of postoperative thrombo-embolic disease. We describe a case in which a fatal pulmonary embolism followed an emergency Caesarean section for which the patient was given a spinal anaesthetic. We believe it to be thejirst time this has been reported.
Key words Anaesthesia; obstetric. Anaesthetic technique, regional; spinal. Complications; pulmonary embolism.
The report on Confidential enquiries into maternal deaths in the United Kingdom 1985-87, shows that pulmonary embolism and hypertensive disorders of pregnancy remain the most common causes of maternal mortality [I]. Of the 13 postpartum deaths from pulmonary embolism, seven followed Caesarean section, suggesting that the risk after operative delivery is markedly increased compared with vaginal delivery.
Case history An unmarried 29-year-old primiparous woman presented in spontaneous labour at 41 weeks' gestation. Her antenatal course had been uneventful and did not include any periods of immobilisation. She weighed 97.4 kg, smoked 10 cigarettes a day and had been normotensive throughout her pregnancy. Labour initially progressed well, during which she required for analgesia one intramuscular injection of pethidine 100 mg and Entonox. After 9 h her labour failed to progress because of cephalopelvic disproportion and an emergency Caesarean section became necessary. There was no fetal distress. The pre-operative haemoglobin level was 12 g.dl-' and baseline readings of heart rate 100 beats.min-', blood pressure 130/85 mmHg and an oxygen saturation of 96%
when breathing air were obtained. After premedication with 30 ml of sodium citrate the patient's circulation was preloaded with 1500 ml compound sodium lactate solution. She was turned onto her right side and a 26 g spinal needle was inserted at the L2-3interspace. Clear cerebrospinal fluid was obtained and 2.5 ml of hyperbaric 0.5% bupivacaine was injected into the subarachnoid space. A bolus dose of 9 mg of ephedrine was given intravenously as prophylaxis against hypotension. Twelve minutes later the patient was delivered of a live female infant weighing 4.08 kg, with Apgar scores of 9 at 1 min and 10 at 5 min. The operation was complete 53 min after the spinal injection. There were no episodes of hypotension and the blood loss was estimated to be 400 ml. The patient recovered well, did not develop a headache and was sitting out of bed 20 h after the operation. She required three intramuscular injections of papaveretum 20 mg for analgesia in the first 24 h and nothing after that. On the second postoperative day her temperature was 37.9" C, but this settled spontaneously. It was noted that her calves were not tender. All observations remained normal, but owing to social circumstances she was not discharged until the eighth postoperative day. The following day she was found dead at home. A postmortem revealed thromboses in the deep veins of the left leg and massive bilateral pulmonary emboli totally
S.P. McHale, MB, BS, BSc, FCAnaes, Registrar, M.D.V. Tilak, MB, BS, MRCP, FFARCSI, Senior House Officer, P.N. Robinson, MB, ChB, FFARCS, Consultant, Department of Anaesthetics, Edgware General Hospital, Edgware, Middlesex HA8 OAD. Correspondence should be addressed to Dr P.N. Robinson please. Accepted 23 June 199I . 0003-2409/92/020128 + 03 %03.00/0
@ 1992 The Association of Anaesthetists of Gt Britain and Ireland
128
Fatal pulmonary embolism following spinal anaethesia for Caesarean section Table 1. Postpartum maternal deaths from pulmonary embolism, England and Wales 1970-87, compared with United Kingdom 1985-87. Adapted from the Report on conJidential enquiries into maternal deaths in the United Kingdom 1985-87, London, 1991 HMSO.
England and Wales
United Kingdom
1970-72 1973-75 1976-78 1979-81 1982-84 1985-87 1985-87
Deaths after vaginal delivery
Deaths after Caesarean section
22 13 20 4 4 5 6
15
6 9 7 12 3 7
Total 37 19 29 II 16 8 13
occluding both main trunks of the pulmonary artery, with extension into all the peripheral vessels on the right side. There were no signs of thrombosis elsewhere and all other organs were normal. The cause of death was given by the coroner as massive bilateral pulmonary emboli due to deep vein thrombosis as a result of Caesarean section.
Discussion Pregnancy is known to be a hypercoagulable state, with an increase in the clotting factors 1, 2, 7, 8, 9, 10 and 12 [2]. There is also a decrease in the level of antithrombin 111 [3] and of plasma fibrinolytic activity [4]. Although the hyperdynamic circulation of pregnancy means that the overall circulation time is reduced, venous return from the lower limbs is decreased as the pregnant uterus obstructs the inferior vena cava. Thus the risk of thrombo-embolic disease is increased sixfold compared with the nonpregnant state, and is further increased by previous thrombo-embolism, obesity, lupus anticoagulant, immobilisation and operative delivery [ 11. Over the last decade clinical studies have suggested that anaesthesia may influence the development of postoperative deep venous thrombosis. Compared with general anaesthesia, subarachnoid block is associated with a significant decrease in the frequency of deep venous thrombosis (DVT) and pulmonary embolism following hip surgery [5-81. There is similar evidence for extradural blockade and knee surgery [9]. This may be due to an increase in blood flow in the lower limbs [lo] consequent upon vasodilatation, a decrease in platelet aggregation [I 11, enhanced fibrinolysis [I21 and a decrease in blood viscosity [13]. The latter effect is a combination of the preload, the increased deformability of red cells and the vasodilation associated with subarachnoid blocks. The reports on confidential enquiries into maternal death show that the number of postpartum deaths from pulmonary embolism has decreased since the 1970-72 triennium (Table I). Since this time there has undoubtedly been an increase in the use of regional anaesthesia but no study has yet shown that either subarachnoid or extradural blockade is associated with a decrease in thrombo-embolic phenomena in obstetric practice. Part of the problem lies in the diagnosis of DVT which is notoriously difficult from clinical signs alone. Furthermore, as less than 10% of all pulmonary emboli are fatal [14], the report on maternal mortality will show only a small percentage of the total
129
number of pulmonary emboli occurring in the pregnant population. The methods commonly used for prophylaxis against DVT include low dose subcutaneous heparin, intermittent pneumatic compression of the calves, elasticated stockings, low dose aspirin and ankle supports. Only the first of these is of proven benefit in abdominal surgery [15]. In the case reported here the patient’s ankles were supported away from the operating table. Theoretically, subarachnoid anaesthesia may be of benefit as an additional prophylaxis against thromboembolism when used with subcutaneous heparin. Early mobility is desirable, and perhaps a smaller volume of local anaesthetic solution should be used, and thus give a less dense motor block. If a smaller volume is injected then it may be necessary to use a combination epidural/spinal technique so that an inadequate block could be improved upon. However, if this was necessary a dense motor block would probably be produced. An advantage of using a combined spinal and epidural technique would be in the provision of postoperative analgesia. In a recent study, it was shown that in a group of patients who received a continuous infusion of low dose bupivacaine for the 3 days following knee replacement, there was a decrease in the incidence of DVT [9]. These patients also wore elasticated stockings. Alternatively, the epidural injection of an opioid could be used for postoperative analgesia. Once analgesia is adequate, mobilisation should be actively encouraged. The routine continuation of intravenous infusions may not be necessary in the patient who has had an uncomplicated Caesarean section with a regional anaesthetic. She could be given adequate oral fluids and, relieved of the infusion and drip stand, be more able to mobilise. All pregnant women are at risk of developing a DVT and those that have an operation have an increased risk. Should we be taking prophylactic measures in all women undergoing Caesarean section? Should low dose heparin with elasticated stockings become routine practice for such women? In the case reported, the patient possessed three risk factors for the development of DVT: she was overweight, pregnant and underwent an operation. Although it is not supported by any studies, perhaps people in risk groups should be offered a regional anaesthetic with subcutaneous heparin, postoperative epidural analgesia and early oral fluids. However, as with this case and in the majority of postnatal women who die following pulmonary embolism, the in-hospital postdelivery course was unremarkable and contained no significant periods of immobilisation.
References [I] Report on ConJdential Enquiries into Maternal Deaths in lhe United Kingdom 1985-87. London: HMSO, 1991. [2] BONNAR J, MCNICOLGP, DOUGLASAS. The blood coagulation and fibrinolytic systems in the newborn and the mother at birth. Journal of Obstetrics and Gynaecology of the British Commonweath 1971; 78: 355-60. [3] ZUCKER ML, GOMPERTS ED, MARCUSRG. Prophylactic and therapeutic use of anticoagulants in inherited antithrombin I11 deficiency. South African Medical Journal 1976; 5 0 1743-8. [4] BONNARJ, MCNICOL GP, DOUGLAS AS. Fibrinolytic enzyme system and pregnancy. British Medical Journal 1969; 3: 387-9. [5] THORBURN J, LOUDEN JR, VALLANCER. Spinal and general anaesthesia in total hip replacement: frequency of deep vein thrombosis. British Journal of Anaesthesiu 1980; 52: 1 I 17-2 I .
I30
S.P. McHale. M.D.V. Tilak and P . N . Robinson
[6] DAVIS FM, QUINCEM, LAURENSON VG. Deep vein thrombosis and anaesthetic technique in emergency hip surgery. British Medical Journal 1980; 281: 1528-9. HY, GRAY1, SMITHG. Effects of [7] MCKENZIE PJ, WISHART anaesthetic technique on deep vein thrombosis. A comparison of subarachnoid and general anaesthesia. British Journal of Anaesthesia 1985; 57: 853-7. (81 MODIGJ. Influence of regional anesthesia, local anesthetics, and sympathicomimetics on the pathophysiology of deep vein thrombosis. Acta Chirurgica Scandinavica 1989; 5 5 0 I 19-27. LS, NIELSEN PT, LEFFERSA. 191 J0RCENSEN LN, RASMUSSEN ALBRECHT-BESTE E. Antithrombotic efficacy of continuous extradural analgesia after knee replacement. British Journal of Anaesrhesia I99 I ; 66: 8- 12. [lo] COUSINS MJ, WRIGHT CJ. Graft, muscle, skin blood flow after epidural block in vascular surgical procedures. Surgery, Gynecology and Obstetrics 1971; 133: 59-64.
[ I I] BORC T, MODIGJ. Potential antithrombotic effects of local anaesthetics due to their inhibition of platelet aggregation. Acta Anaesthesiologica Scandinavica 1985; 2 9 73942. SG, FORSTER SJ, COOPER GM, HUGHES [I21 SIMPSON PJ, RADFORD GO. The fibrinolytic effects of anaesthesia. Anaesthesiu 1982; 37: 3-8. [I31 DRUMMOND AR, DRUMMOND MM, MCKENZIEPJ, LOWE GDO, SMITHG, FORBESCD, WISHARTHY. The effects of general and spinal anaesthesia on red cell deformability and blood viscosity in patients undergoing surgery for fractured P. eds Haemorrheology neck of femur. In STOLZJF, DROUIN and diseases. Paris: Doin Editeurs, 1980: 44-50. [I41 MOSER KM. Pulmonary embolism. American Review o / Respiratory Disease 1977; 115: 829-52. [IS] International Multicentre Trial; Prevention of fatal postoperative pulmonary embolism by low doses of heparin. Lancet 1977; ii: 45-51.
